ArticlePDF Available

Kawamori T, Lubet R, Steele VE, Kellof GJ, Kaskey RB, Rao CV, Reddy BSChemopreventive effect of curcumin, a naturally occurring anti-inflammatory agent, during the promotion/progression stages of cancer. Cancer Res 59: 597-601

Authors:

Abstract

Curcumin, derived from the rhizome of Curcuma longa L. and having both antioxidant and anti-inflammatory properties, inhibits chemically induced carcinogenesis in the skin, forestomach, and colon when it is administered during initiation and/or postinitiation stages. This study was designed to investigate the chemopreventive action of curcumin when it is administered (late in the premalignant stage) during the promotion/progression stage of colon carcinogenesis in male F344 rats. We also studied the modulating effect of this agent on apoptosis in the tumors. At 5 weeks of age, groups of male F344 rats were fed a control diet containing no curcumin and an experimental AIN-76A diet with 0.2% synthetically derived curcumin (purity, 99.9%). At 7 and 8 weeks of age, rats intended for carcinogen treatment were given s.c. injections of azoxymethane (AOM) at a dose rate of 15 mg/kg body weight per week. Animals destined for the promotion/progression study received the AIN-76A control diet for 14 weeks after the second AOM treatment and were then switched to diets containing 0.2 and 0.6% curcumin. Premalignant lesions in the colon would have developed by week 14 following AOM treatment. They continued to receive their respective diets until 52 weeks after carcinogen treatment and were then sacrificed. The results confirmed our earlier study in that administration of 0.2% curcumin during both the initiation and postinitiation periods significantly inhibited colon tumorigenesis. In addition, administration of 0.2% and of 0.6% of the synthetic curcumin in the diet during the promotion/progression stage significantly suppressed the incidence and multiplicity of noninvasive adenocarcinomas and also strongly inhibited the multiplicity of invasive adenocarcinomas of the colon. The inhibition of adenocarcinomas of the colon was, in fact, dose dependent. Administration of curcumin to the rats during the initiation and postinitiation stages and throughout the promotion/progression stage increased apoptosis in the colon tumors as compared to colon tumors in the groups receiving AOM and the control diet. Thus, chemopreventive activity of curcumin is observed when it is administered prior to, during, and after carcinogen treatment as well as when it is given only during the promotion/progression phase (starting late in premalignant stage) of colon carcinogenesis.
1999;59:597-601. Cancer Res
Toshihiko Kawamori, Ronald Lubet, Vernon E. Steele, et al.
Stages of Colon Cancer
Anti-Inflammatory Agent, during the Promotion/Progression
Chemopreventive Effect of Curcumin, a Naturally Occurring
Updated version
http://cancerres.aacrjournals.org/content/59/3/597
Access the most recent version of this article at:
Cited Articles
http://cancerres.aacrjournals.org/content/59/3/597.full.html#ref-list-1
This article cites by 39 articles, 20 of which you can access for free at:
Citing articles
http://cancerres.aacrjournals.org/content/59/3/597.full.html#related-urls
This article has been cited by 48 HighWire-hosted articles. Access the articles at:
E-mail alerts
related to this article or journal.Sign up to receive free email-alerts
Subscriptions
Reprints and
.pubs@aacr.orgDepartment at
To order reprints of this article or to subscribe to the journal, contact the AACR Publications
Permissions
.permissions@aacr.orgDepartment at
To request permission to re-use all or part of this article, contact the AACR Publications
on June 4, 2013. © 1999 American Association for Cancer Research. cancerres.aacrjournals.org Downloaded from
[CANCER RESEARCH 59, 597–601, February 1, 1999]
Chemopreventive Effect of Curcumin, a Naturally Occurring Anti-Inflammatory
Agent, during the Promotion/Progression Stages of Colon Cancer
1
Toshihiko Kawamori, Ronald Lubet, Vernon E. Steele, Gary J. Kelloff, Robert B. Kaskey, Chinthalapally V. Rao,
and Bandaru S. Reddy
2
Division of Nutritional Carcinogenesis, American Health Foundation, Valhalla, New York 10595 [T. K., C. V. R., B. S. R.]; Chemoprevention Branch, National Cancer Institute,
Bethesda, Maryland 20892 [R. L., V. E. S., G. J. K.]; and Gene Print, Inc., Bala Cynwyd, Pennsylvania [R. B. K.]
ABSTRACT
Curcumin, derived from the rhizome of Curcuma longa L. and having
both antioxidant and anti-inflammatory properties, inhibits chemically
induced carcinogenesis in the skin, forestomach, and colon when it is
administered during initiation and/or postinitiation stages. This study was
designed to investigate the chemopreventive action of curcumin when it is
administered (late in the premalignant stage) during the promotion/pro-
gression stage of colon carcinogenesis in male F344 rats. We also studied
the modulating effect of this agent on apoptosis in the tumors. At 5 weeks
of age, groups of male F344 rats were fed a control diet containing no
curcumin and an experimental AIN-76A diet with 0.2% synthetically
derived curcumin (purity, 99.9%). At 7 and 8 weeks of age, rats intended
for carcinogen treatment were given s.c. injections of azoxymethane
(AOM) at a dose rate of 15 mg/kg body weight per week. Animals destined
for the promotion/progression study received the AIN-76A control diet for
14 weeks after the second AOM treatment and were then switched to diets
containing 0.2 and 0.6% curcumin. Premalignant lesions in the colon
would have developed by week 14 following AOM treatment. They con-
tinued to receive their respective diets until 52 weeks after carcinogen
treatment and were then sacrificed. The results confirmed our earlier
study in that administration of 0.2% curcumin during both the initiation
and postinitiation periods significantly inhibited colon tumorigenesis. In
addition, administration of 0.2% and of 0.6% of the synthetic curcumin in
the diet during the promotion/progression stage significantly suppressed
the incidence and multiplicity of noninvasive adenocarcinomas and also
strongly inhibited the multiplicity of invasive adenocarcinomas of the
colon. The inhibition of adenocarcinomas of the colon was, in fact, dose
dependent. Administration of curcumin to the rats during the initiation
and postinitiation stages and throughout the promotion/progression stage
increased apoptosis in the colon tumors as compared to colon tumors in
the groups receiving AOM and the control diet. Thus, chemopreventive
activity of curcumin is observed when it is administered prior to, during,
and after carcinogen treatment as well as when it is given only during the
promotion/progression phase (starting late in premalignant stage) of colon
carcinogenesis.
INTRODUCTION
Colorectal cancer, one of the leading causes of cancer deaths in
both men and women in the United States, accounts for ;56,000
deaths annually (1). Although several epidemiological and laboratory
studies suggest a relationship between large bowel cancer risk and
dietary factors (2–4), there is increasing evidence that a high con-
sumption of fruits and vegetables and intake of certain nonnutrients
that are present in foods reduce the risk of colon carcinogenesis (5).
Although risk reduction by nutritional intervention may not be suffi-
cient to protect high-risk individuals against colon cancer develop-
ment, an alternative or complementary effective approach for second-
ary prevention has been to identify the agents with chemopreventive
potency and to evaluate them in high-risk individuals in combination
with nutritional intervention (68).
It is noteworthy that the use of medicinal plants or their crude
extracts in the prevention and/or treatment of several chronic diseases
has been traditionally practiced in various different ethnic societies
worldwide. Turmeric, the powdered rhizome of Curcuma longa L.,
has been used to treat a variety of inflammatory conditions and
chronic diseases (9, 10); it is also used as coloring and flavoring
additive to foods. Curcumin [Fig. 1; diferuloylmethane; 1,7-bis-(4-
hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione], which has
been identified as the major pigment in turmeric, possesses both
anti-inflammatory (11–13) and antioxidant properties (14, 15). It has
been demonstrated that topical application of curcumin inhibits ben-
zo(a)pyrene-induced DNA adduct formation, and development of skin
tumors as well as TPA
3
-induced epidermal DNA synthesis and tumor
promotion in mouse skin (16–18). Curcumin has a strong inhibitory
effect on cell proliferation in the HT-29 and HCT-15 human colon
cancer cell lines (19). Importantly, dietary administration of curcumin
during initiation and/or postinitiation periods significantly suppresses
development of chemically induced forestomach, duodenal, and colon
tumors in CF-1 mice (20); it also reduces formation of focal areas of
dysplasia and aberrant crypt foci in the colon that are early preneo-
plastic lesions in rodents (21, 22). Pereira et al. (23) have reported that
administration of 0.8 and 1.6% curcumin continuously during the
initiation and postinitiation phases significantly inhibited develop-
ment of AOM-induced colonic adenomas in rats. We have shown that
continuous dietary administration of 0.2% curcumin during the initi-
ation and postinitiation stages significantly inhibited the incidence and
multiplicity of AOM-induced colon adenocarcinomas and the tumor
burden in F344 rats (24). Although all of the above studies clearly
demonstrate the potential chemopreventive activity of curcumin dur-
ing the initiation and postinitiation periods of colon carcinogenesis,
there were no studies on the efficacy of this agent during the promo-
tion/progression stage when the premalignant lesions would have
developed. We deemed it important to show that curcumin treatment
can be delayed after the carcinogen administration in experimental
carcinogenesis and still be effective, so as to provide baseline knowl-
edge for possible clinical use of this agent in secondary prevention of
colon cancer in high-risk individuals, such as patients with colonic
polyps.
Curcumin was shown to inhibit colon carcinogenesis during the
postinitiation stage through the modulation of COX activity in the
tumor tissue (24). COXs are involved in the synthesis of PGs, which
have been shown to affect tumor growth (24), suggesting that effects
on the arachidonic acid cascade by curcumin may play a role in its
tumor-inhibitory activity. We and others have shown previously that
several inhibitors of PG synthesis, such as aspirin, ibuprofen, sulin-
dac, and piroxicam suppress colon carcinogenesis in laboratory ani-
mal model assays (25–28). Inhibition of colon carcinogenesis was
consistently associated with a decrease in the activity of COX in colon
Received 8/24/98; accepted 12/3/98.
The costs of publication of this article were defrayed in part by the payment of page
charges. This article must therefore be hereby marked advertisement in accordance with
18 U.S.C. Section 1734 solely to indicate this fact.
1
Supported in part by United States Public Health Service Grant CA17613 and
NO1-CN-55150 from the National Cancer Institute.
2
To whom requests for reprints should be addressed, at the American Health Foun-
dation, Valhalla, NY 10595.
3
The abbreviations used are: TPA, 12-O-tetradecanoylphorbol-13-acetate; AOM,
azoxymethane; COX, cyclooxygenase; PG, prostaglandin; NSAID, nonsteroidal anti-
inflammatory drug; LOX, lipoxygenase; HETE, hydroxyeicosatetraenoic acid.
597
on June 4, 2013. © 1999 American Association for Cancer Research. cancerres.aacrjournals.org Downloaded from
tumors (25, 26, 28). Evidence also suggests that curcumin acts on
pathways that may inhibit cell proliferation (19) and enhance apop-
tosis (29). In vitro studies by Hanif et al. (19) suggest that curcumin
inhibits colon cancer cell proliferation, independent of its ability to
inhibit PG synthesis. Furthermore, transformation of colorectal epi-
thelium into adenomas and adenocarcinomas has been shown to be
associated with progressive inhibition of apoptosis, suggesting that
inhibition of apoptosis in colon carcinogenesis may contribute to
tumor growth and promote neoplastic progression (30).
This study was designed to specifically investigate the chemopre-
ventive efficacy and dose-response effect of curcumin when it is
administered late in the premalignant stage, representing the promo-
tion/progression phase of colon carcinogenesis in F344 rats. In addi-
tion, the effect of dietary curcumin on apoptosis in colon tumors was
determined.
MATERIALS AND METHODS
Animals, Diets, and Carcinogen. Weanling male F344 rats were received
from Charles River Breeding Laboratories (Kingston, NY). AOM was pur-
chased from Ash Stevens (Detroit, MI). Synthetically derived curcumin (purity
.99.9% diferuloylmethane) was kindly provided by Gene Print, Inc. Bala
Cynwyd, PA as part of the National Cancer Institute’s project for investiga-
tional studies of this compound. All ingredients for the semipurified diet were
purchased from Dyets, Inc (Bethlehem, PA). The experimental diets were
prepared weekly in our laboratory by adding curcumin at 0.2 and 0.6% levels
instead of cornstarch (Table 1). The experimental and control diets were stored
in a cold room.
Efficacy Study. The experimental protocols followed those detailed in our
previous publications (27). Briefly, weanling male F344 rats were quarantined
for 7 days and had access to modified AIN-76A control diet (Table 1).
Following quarantine, at 5 weeks of age, all animals were randomly distributed
by weight into the various experimental groups. As shown in Fig. 2, the points
at which the animals received the test diets from 2 weeks before, during, and
after carcinogen treatment to termination of the study were designated initia-
tion and postinitiation stages, whereas promotion/progression stages represent
the point at which the animals received test diets from 14 weeks after carcin-
ogen treatment until the end of the study. Beginning at 5 weeks of age, groups
of animals in the initiation and postinitiation study had access to either control
diet or experimental diet containing 0.2% curcumin, whereas the rats for the
assays testing efficacy during the promotion/progression stage received the
control diet. At 7 weeks of age, all rats except those intended for vehicle
treatment received s.c. injections of AOM at a dose rate of 15 mg/kg body
weight, once weekly for 2 weeks. Rats in vehicle-treated control groups were
injected with an equal volume of normal saline. The rats designated for the
intervention during the promotion/progression stage and maintained on the
control diet were then transferred to experimental diets containing 0.2 or 0.6%
curcumin beginning 14 weeks after the second dose of AOM (Fig. 2). Our past
experience on AOM-induced colon carcinogenesis suggests that the premalig-
nant lesions in the colon would have developed by week 14 following carcin-
ogen administration (26). This dietary regimen was continued until termination
of the experiment 52 weeks after the last carcinogen treatment. Body weights
were recorded every 2 weeks for the first 10 weeks and then every 4 weeks. At
the scheduled termination, all animals were killed by CO
2
euthanasia. After
laparotomy, the entire gastrointestinal tract was resected and opened longitu-
dinally, and the contents were flushed with normal saline. Colon tumors were
recorded by gross observation using a dissection microscope. All other organs,
including kidney, liver, and lungs were grossly examined under the dissection
microscope for any abnormalities. For histopathological evaluation, colon
tumors were fixed in 10% neutral buffered formalin, embedded in paraffin
blocks, cut into multiple sections, and processed. The slides were stained with
H&E and examined. The histological criteria used for classification of intes-
tinal tumors were as described previously (24, 26). Upon termination of this
study, more than 90% of the colon tumors had developed into adenocarcino-
mas that were classified as invasive or noninvasive. The invasive adenocarci-
nomas were mostly signet-ring mucinous types, invading the muscularis mu-
cosa deep into the intestinal wall and beyond. The noninvasive
adenocarcinomas were those growing outward toward the intestinal lumen
without invasion of the muscularis mucosa. They were usually well-differen-
tiated adenocarcinomas.
Fig. 1. Chemical structure of curcumin [1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-
heptadiene-3,5-dione].
Fig. 2. Experimental design for evaluation of the chemopre-
ventive activity of curcumin against colon carcinogenesis.
Groups of male F344 rats were fed the experimental diets
containing 0 or 0.2% curcumin beginning 2 weeks prior to
exposure to AOM, during treatment, and until termination (ini-
tiation and postinitiation stages). Additional groups of animals
who were on control diet (0% curcumin) 2 weeks prior to
exposure of AOM, during treatment, and until 14 weeks after
AOM treatment were transferred to experimental diets contain-
ing 0.2 and 0.6% curcumin and were on this regimen until
termination (promotion/progression stage). AOM was given to
the animals s.c. at the beginning of 7 and 8 weeks of age at 15
mg/kg body weight.
Table 1 Percentage composition of experimental semipurified diets
Ingredients
% composition
Control diet
a
Experimental diets
Casein 2.0 20.0
DL-Methionine 0.3 0.3
Cornstarch 52.0 51.8 or 51.4
Dextrose 13.0 13.0
Corn oil 5.0 5.0
Alphacel 5.0 5.0
Mineral mix, AIN 3.5 3.5
Vitamin mix, AIN revised 1.0 1.0
Choline bitartrate 0.2 0.2
Curcumin
b
0 0.2 or 0.6
a
Adopted from the AIN reference diet (AIN-76A), with modification of the source of
carbohydrate.
b
Curcumin was added to the diets instead of cornstarch.
598
CHEMOPREVENTIVE EFFECT OF CURCUMIN
on June 4, 2013. © 1999 American Association for Cancer Research. cancerres.aacrjournals.org Downloaded from
Detection of Apoptosis. Although apoptosis is characterized by DNA
fragmentation, and the appearance of a “ladder” of nucleosomal-sized frag-
ments on agarose gel electrophoresis has been used as a hallmark of apoptosis,
DNA cleavage is not universally found in apoptosis (31). A ladder of DNA
fragments has also been associated with necrosis in certain types of cells (32,
33). The gold standard for determination of apoptosis has been set through
observation of characteristic morphological changes by electron microscopy
(32, 34) or alternatively, by light microscopy (29, 35, 36). In this study, we
examined the modulation of apoptosis by curcumin by quantifying the number
of apoptotic cells in H&E-stained histological sections of colon tumors using
light microscopy (29, 36). Apoptotic cells were identified by cell shrinkage,
nuclear condensation, and formation of apoptotic bodies (29, 36). The light
microscopic appearance of apoptotic bodies are quite diverse; most are round
or roughly oval in shape. Apoptotic bodies vary in size, but they are a little
smaller than the parent cells. Some apoptotic cells contain pyknotic chromatin,
and some are devoid of a nuclear component (29, 36). The apoptotic index,
which represents the percentage of cells exhibiting apoptosis, was determined
by counting at least 300 cells in randomly chosen fields. All slides were scored
by one person who was blinded to the experimental listing by means of code
numbers.
Statistical Analysis. Data on body weights were compared among the
levels of test agent using Student’s t test. The comparative colon tumor
incidence (total number of colon tumor-bearing rats with respect to the total
number of rats at risk) in the animals fed the control diet and those given
experimental diets was analyzed using Armitage’s
x
2
method. Tumor multi-
plicities (total number of colon tumors per animal) were calculated for each
dietary group; the significance of the differences between results in groups on
the control diet and experimental diets containing curcumin was analyzed
using the unpaired Student’s t test, accounting for unequal variance. The
apoptotic index, which is expressed as the percentage of cells exhibiting
apoptosis was analyzed by unpaired Student’s t test. Differences were consid-
ered statistically significant at P , 0.05.
RESULTS
General Observations. The body weights of rats who received the
experimental diets containing 0.2% of curcumin starting from 2 weeks
before, during, and after carcinogen treatment to termination of the
study (initiation and postinitiation stages) and containing 0.2 or 0.6%
curcumin beginning from 14 weeks after carcinogen treatment until
the end of the study (promotion/progression stage) were comparable
to weights of those fed the control diet only (Table 2). As expected,
vehicle-treated animals in all groups weighed slightly more than those
treated with AOM during the course of the study. In vehicle-treated
rats, experimental diets containing curcumin did not produce any
gross changes in any organs and, thus, showed no toxicity.
Tumor Data. There were no tumors among rats given vehicle only
and maintained on control or experimental diets containing curcumin.
The results, summarized in Table 3, indicate that administration of
AOM induced adenomas and adenocarcinomas of the colon in ;9%
and 82% of rats, respectively, who were fed the control diet. Because
of long-term nature of this study (52 weeks), most of the colon tumors
had become adenocarcinomas. Administration of 0.2% curcumin dur-
ing the initiation and postinitiation stages (before, during and after
carcinogen treatment) significantly inhibited the incidence of nonin-
vasive adenocarcinomas (59% inhibition; P , 0.05), multiplicities of
noninvasive adenocarcinomas (71% inhibition; P , 0.01), and total
(noninvasive plus invasive) adenocarcinomas of the colon (34% in-
hibition; P , 0.05). The incidences of adenomas could not be com-
pared among different groups because of low yield of this lesion.
Administration of 0.2% curcumin during the promotion/progression
stages (14 weeks after carcinogen treatment) also significantly inhib-
ited the incidence of invasive adenocarcinomas of the colon (54%
inhibition; P , 0.05). Although the inhibition of the incidences and
multiplicities of noninvasive adenocarcinomas had reached 54 and
44%, respectively, in the rats given 0.2% curcumin during the pro-
motion/progression stage, the differences were not statistically signif-
icantly (P . 0.05). It is noteworthy that administration of 0.2%
curcumin during the promotion/progression stage significantly sup-
pressed total colon tumor incidence and multiplicity (adenomas plus
adenocarcinomas) as compared to results with the control diet
Table 2 Effect of dietary curcumin on body weights of male F344 rats
Experimental
group
No. of
animals/group
Body weights (g) of animals on experimental diets
Week 0 Week 1 Week 4 Week 12 Week 24 Week 36 Week 44 Week 52
AOM-treated
Control diet 36 115 6 10
a
150 6 12 224 6 14 323 6 22 395 6 25 422 6 27 437 6 38 430 6 40
0.2% curcumin
b
36 115 6 8 139 6 11 219 6 17 318 6 20 384 6 24 417 6 40 428 6 55 433 6 54
0.2% curcumin
c
36 115 6 8 148 6 10 221 6 13 322 6 19 392 6 27 433 6 32 444 6 42 437 6 49
0.6% curcumin
c
36 112 6 9 145 6 12 213 6 16 314 6 22 379 6 32 414 6 30 423 6 40 419 6 40
Vehicle-treated
Control diet 6 113 6 9 147 6 11 231 6 8 340 6 13 419 6 15 463 6 12 481 6 12 484 6 14
0.6% curcumin
c
6 111 6 10 152 6 12 235 6 13 337 6 20 405 6 30 436 6 29 456 6 37 461 6 37
a
Mean 6 SD.
b
Curcumin was administered 2 weeks before, during, and after carcinogen treatment.
c
Curcumin was administered starting 14 weeks after the second dose of carcinogen treatment.
Table 3 Effect of dietary curcumin on AOM-induced colon carcinogenesis in male F344 rats
Experimental
groups
Tumor incidence (% animals with tumors) Tumor multiplicity (tumors/animal)
Adenomas
Adenocarcinomas
Total Adenomas
Adenocarcinomas
TotalNoninvasive Invasive Total Noninvasive Invasive Total
Control diet 9 41 76 82 85 0.09 6 0.28
a
0.59 6 0.73 1.35 6 1.08 1.94 6 1.37 2.03 6 1.42
0.2% curcumin
b
3 (67)
c
17 (59)
d
57 (25) 71 (13) 71 (16) 0.03 6 0.17 0.17 6 0.38 (71)
e
1.11 6 1.14 (17) 1.29 6 1.08 (34)
f
1.31 6 1.12 (35)
f
0.2% curcumin
g
3 (67) 19 (54) 50 (54)
d
64 (22) 64 (25)
d
0.03 6 0.16 0.33 6 0.78 (44) 1.00 6 1.18 (30) 1.33 6 1.25 (31) 1.36 6 1.27 (33)
f
0.6% curcumin
g
6 (33) 9 (78)
h
54 (29) 64 (22) 64 (25)
d
0.06 6 0.23 0.09 6 0.28 (85)
i
0.74 6 0.87 (45)
f
0.83 6 0.84 (57)
i
0.89 6 0.85 (56)
i
a
Mean 6 SD.
b
Animals were administered curcumin beginning 2 weeks before, during, and after carcinogen treatment until termination of the study (initiation and postinitiation period).
c
% inhibition from control diet groups is shown in parenthesis.
d
Significantly different from control diet group by
x
2
-test, P , 0.05.
e
Significantly different from control diet group by Student’s t test, P , 0.01.
f
Significantly different from control diet group by Student’s t test, P , 0.05.
g
Animals were administered curcumin beginning 14 weeks after carcinogen treatment until termination of the study (promotion/progression period).
h
Significantly different from control diet group by
x
2
test, P , 0.01.
i
Significantly different from control diet group by Student’s t test, P , 0.001.
599
CHEMOPREVENTIVE EFFECT OF CURCUMIN
on June 4, 2013. © 1999 American Association for Cancer Research. cancerres.aacrjournals.org Downloaded from
(P , 0.05). As expected, administration of 0.6% curcumin during the
promotion/progression stage also significantly inhibited the incidence
of noninvasive adenocarcinomas (78% inhibition; P , 0.01) and
multiplicities of noninvasive (85% inhibition; P , 0.001) and inva-
sive (45% inhibition; P , 0.05) adenocarcinomas of the colon. In
addition, the incidences and multiplicities of total colon tumors (ad-
enomas plus adenocarcinomas) were reduced when rats were given
0.6% curcumin (25 and 56% inhibition; P , 0.05 and P , 0.01).
These results were analyzed using the linear correlation method for a
dose-response effect. This analysis yielded the correlation coefficients
(r) for multiplicity of adenocarcinomas with increasing levels of
curcumin in the diet from 0 to 0.6%, suggesting a dose-dependent
inhibition of colon tumors (P , 0.05): noninvasive adenocarcinomas,
20.97; invasive adenocarcinomas, 20.95; total adenocarcinomas,
20.97; and total tumors, 20.96.
Apoptosis. Having established the inhibition of colon carcinogen-
esis by dietary administration of 0.2% curcumin during the initiation
and postinitiation stages and the effects by 0.2 and 0.6% curcumin
given during the promotion/progression period, we investigated
whether the inhibition of colon tumorigenesis by curcumin is associ-
ated with the modulation of apoptosis in the colon tumors. Results
summarized in Table 4 indicate that continual administration of 0.2%
curcumin during the initiation and postinitiation stages and feeding
0.2 and 0.6% curcumin during the promotion/progression period
significantly increased the apoptotic index in the colon tumors as
compared to that in tumors of rats given control diet (P , 0.05–
P , 0.002).
DISCUSSION
This study is part of a large-scale evaluation of phytochemicals that
have anti-inflammatory and antioxidant properties for their potential
chemopreventive activities against colon carcinogenesis. The primary
mission of these studies is to identify effective and safe chemopre-
ventive agents that will facilitate the development of cancer-preven-
tive strategies and their application in a clinical setting. Curcumin, a
naturally occurring anti-inflammatory agent and antioxidant, has been
shown to inhibit tumors in several organs, including 7,12-dimethyl-
benz[a]anthracene-induced and TPA-promoted skin tumors, benzo-
(a)pyrene-induced forestomach tumors, and AOM-induced intestinal
tumors in mice (16, 17, 20), to cite a few. Recent studies from our
laboratory and elsewhere that demonstrated an inhibitory effect of
dietary curcumin when administered continuously during the initia-
tion and postinitiation phases (20–24) provided a rationale for eluci-
dating the efficacy of this agent against premalignant lesions during
the promotion/progression stage of colon carcinogenesis.
The results of this study are in agreement with earlier investigations
showing that dietary curcumin inhibits colon carcinogenesis when
administered during the initiation and postinitiation periods (20, 23,
24). Our results also demonstrate for the first time that curcumin, a
naturally occurring anti-inflammatory agent and antioxidant, given as
a dietary supplement during promotion/progression period still inhib-
its tumorigenesis in the colon, suggesting that administration of cur-
cumin may retard growth and/or development of existing neoplastic
lesions in the colon. This also suggests the potential usefulness of this
agent as a chemopreventive agent for individuals at high risk for colon
cancer development, such as patients with polyps. This study further
extends our earlier observations that synthetic NSAIDs, such as pi-
roxicam and sulindac, given during the promotion/progression period
protect against colon tumorigenesis in F344 rats (26, 37). Importantly,
unlike synthetic NSAIDs curcumin does not produce any gastrointes-
tinal toxicity, even at very high doses, which may provide advantage
over synthetic agents.
With regard to the mode of chemopreventive action, curcumin
exhibits a diverse array of metabolic, cellular, and molecular activities
including inhibition of arachidonic acid formation and its further
metabolism to eicosanoids. Studies from our laboratory have demon-
strated that dietary curcumin significantly inhibits phospholipase A
2
in colonic mucosa and tumors leading to the release of arachidonic
acid from phospholipids, alters COX and LOX activities, and modi-
fies PGE
2
levels (24). Several lines of evidence also indicate that the
mechanism of action of curcumin is not limited to PG inhibition. We
had observed earlier that dietary curcumin inhibits LOX activity, and
the production of the LOX metabolites, 5(S)-, 8(S)-, 12(S)-, and
15(S)-HETEs, in the colonic mucosa and in tumors (24). Importantly,
LOX metabolites such as 12(S)-HETE have been shown to promote
tumor cell adhesion, stimulate the spreading of tumor cells, and
augment metastatic potential (3840). Also, a positive correlation
was observed between the levels of 8(S)-HETE and hyperproliferation
and tumor development induced by TPA (41). Moreover, curcumin
inhibits several mediators and enzymes involved in cell mitogenic
signal transduction pathways (42) and activator protein-1 and nuclear
factor
k
B activation (43). Hanif et al. (19) provided evidence that
curcumin inhibits cell proliferation and induces cell cycle changes in
the colonic adenocarcinoma cell lines, HT-29 and HCT-15, and that
this effect is independent of its ability to inhibit PG synthesis. Here,
the inhibitory effects of curcumin administered during the promotion/
progression stage of chemically induced carcinogenesis is associated
with increased apoptosis, suggesting that increased cell death through
apoptosis may be one of the mechanisms by which dietary curcumin
affects this inhibition. The results of this and other studies support the
concept that the capacity to induce apoptosis may be common to many
chemopreventive agents (28, 44, 45). This had certainly been docu-
mented for NSAIDs and other agents that inhibit colon carcinogene-
sis, suggesting that cellular responses to these agents may contribute
to chemopreventive effects (29, 35). The effects of curcumin demon-
strated here resemble those of NSAIDs and thus seem to act strongly
via inhibition of arachidonate metabolism and through reducing cell
proliferation and inducing apoptosis.
In conclusion, the study described here demonstrates for the first
time that dietary administration of curcumin during the promotion/
progression stage of AOM induced colon carcinogenesis significantly
inhibits tumor development in a dose-dependent manner and increases
apoptosis in the colonic tumors. Similar levels of inhibition of colon
tumorigenesis were achieved when 0.2% curcumin was administered
either during initiation and postinitiation periods or promotion/pro-
gression stage, suggesting indirectly that most of chemopreventive
efficacy of this agent is achieved during the promotion/progression
phase in this model. Although the exact mechanisms of its chemo-
preventive action of curcumin remain to be elucidated, it would
appear that modulation of tumorigenesis by this agent is associated
Table 4 Modulating effects of dietary curcumin on apoptosis in colon
adenocarcinomas
Experimental
group
Apoptotic
index
a
(%)
Control diet 5.33 6 0.61
b
0.2% curcumin
c
9.17 6 1.04
d
0.2% curcumin
e
7.56 6 0.82
f
0.6% curcumin
e
8.40 6 0.61
d
a
Apoptotic index represents percentage of cells exhibiting apoptosis.
b
Mean 6 SE; number of adenocarcinomas examined in each group: 10.
c
Animals were administered curcumin beginning 2 weeks before, during, and after
carcinogen treatment until termination of the study (initiation and postinitiation period).
d
Significantly different from the control diet group, P , 0.01.
e
Animals were administered curcumin beginning 14 weeks after carcinogen treatment
until termination of the study (promotion/progression period).
f
Significantly different from the control diet group, P , 0.05.
600
CHEMOPREVENTIVE EFFECT OF CURCUMIN
on June 4, 2013. © 1999 American Association for Cancer Research. cancerres.aacrjournals.org Downloaded from
not only with the alteration of arachidonic acid metabolism through
LOX and COX pathways (24) but also through mechanisms that are
independent of eicosanoid metabolism, such as cell proliferation and
apoptosis in the colon tumors.
ACKNOWLEDGMENTS
We thank Laura Nast for preparation of the manuscript, Ilse Hoffmann for
editing the manuscript, and staff of the Research Animal Facility and Histopa-
thology Facility for expert technical assistance. We thank Bob Kaskey of Gene
Print (Bala Cnwyd, PA) for kindly providing curcumin.
REFERENCES
1. American Cancer Society. Cancer Statistics 1998. CA Cancer J. Clin., 48: 11–42,
1998.
2. Wynder, E. L., Kajitani, T., Ishidawa, S., Dodo, H., and Takano, A. Environmental
factors in cancer of colon and rectum. Cancer (Phila.), 23: 1210–1220, 1969.
3. Willett, W. C., Stampfer, M. J., Colditz, G. A., Rosner, B. A., and Speizer, F. E.
Relation of meat, fat and fiber intake to the risk of colon cancer in a prospective study
among women. N. Engl. J. Med., 323: 1664–1672, 1990.
4. Reddy, B. S. Nutritional factors and colon cancer. Crit. Rev. Food Sci. Nutr., 35:
175–190, 1995.
5. Potter, J. D., and Steinmatz, K. Vegetables, fruits and phytoestrogens as preventive
agents. IARC Sci. Publ., 139: 61–90, 1996.
6. Wattenberg, L. W. Chemoprevention of cancer by naturally occurring and synthetic
compounds. In: M. Wattenberg, C. W. Lipkin, C. W. Boone, and G. J. Kelloff (eds.),
Cancer Chemoprevention, pp. 19–39. Boca Raton, FL: CRC Press, 1992.
7. Kelloff, G. J., Boone, C. W., Malone, W. E., and Steele, V. E. Recent results in
preclinical and clinical drug development of chemopreventive agents at the National
Cancer Institute. In: L. W. Wattenberg, M. Lipkin, C. W. Boone, and G. J. Kelloff
(eds.), Cancer Chemoprevention, pp. 41–56. Boca Raton, FL: CRC Press, 1992.
8. Greenwald, P., Kelloff, G. J., Boone, C. W., and McDonald, S. N. Genetic and
cellular changes in colorectal cancer: proposed targets of chemopreventive agents.
Cancer Epidemiol. Biomark. Prev., 4: 691–702, 1995.
9. Ammon, H. P. T., and Wahl, M. A. Pharmacology of Curcuma longa. Planta Med.,
57: 1–7, 1991.
10. Nadkarani, K. M. Curcuma longa. In: K. M. Nadkarani (ed.), India Materia Medica,
pp. 414416. Bombay: Popular Prakashan Publishing Co., 1976.
11. Tonnesen, H. H. Chemistry of curcumin and curcuminoids. In: C-T. Ho, C. Y. Lee,
and M-T. Haung (eds.), Phenolic Compounds in Food and their Effect of Health, Vol.
1: Analysis, Occurrence and Chemistry, ACS Symposium Series No. 506, pp.
143–153. Washington, DC: American Chemical Society, 1992.
12. Srimal, R. C., and Dhawan, B. N. Pharmacology of diferuloylmethane (curcumin), a
non-steroidal anti-inflammatory agent. J. Pharm. Pharmacol., 25: 447–452, 1973.
13. Satoskar, R. R., Shah, S. J., and Shenoy, S. G. Evaluation of antiinflammatory
property of curcumin (diferuloylmethane) in patients with postoperative inflamma-
tion. Int. J. Clin. Pharmacol. Ther. Toxicol., 24: 651–654, 1986.
14. Sharma, O. P. Antioxidant activity of curcumin and related compounds. Biochem.
Pharmacol., 25: 1811–1812, 1976.
15. Toda, S., Miyase, T., Arichi, H., Tanizawa, H., and Takino, Y. Natural antioxidant III.
Antioxidative components isolated from rhizome of Curcuma longa L. Chem. Pharm.
Bull. (Tokyo), 33: 1725–1728, 1985.
16. Huang, M-T., Smart, R. C., Wong, G-Q., and Conney, A. H. Inhibitory effect of
curcumin, chlorogenic acid, caffeic acid, and ferulic acid on tumor promotion in
mouse skin by 12-O-tetradecanoylphorbol-13-acetate. Cancer Res., 48: 5941–5946,
1988.
17. Huang, M-T., Wang, Z. Y., Georgiadis, C. A., Laskin, J. D., and Conney, A. H.
Inhibitory effect of curcumin on tumor initiation by benzo[a]pyrene and 7,12-
dimethylbenz[a]anthracene. Carcinogenesis (Lond.), 13: 2183–2186, 1992.
18. Huang, M. T., Ma, W., Yen, P., Xie, J. G., Han, J., Frenkel, K., Grunberger, D., and
Conney, A. H. Inhibitory effects of topical application of low doses of curcumin on
12-O-tetradecanoylphorbol-13-acetate-induced tumor promotion and oxidized DNA
bases in mouse epidermis. Carcinogenesis (Lond.), 18: 83–88, 1997.
19. Hanif, R., Qiao, L., Shiff, S. J., and Rigas, B. Curcumin, a natural plant phenolic food
additive, inhibits cell proliferation and induces cell cycle changes in colon adenocar-
cinoma cell lines by a prostaglandin-independent pathways. J. Lab. Clin. Med., 130:
576–584, 1997.
20. Huang, M-T., Lou, Y-R., Ma, W., Newmark, H., Reuhl, K., and Conney, A. H.
Inhibitory effect of dietary curcumin on forestomach, duodenal and colon carcino-
genesis in mice. Cancer Res., 54: 5841–5847, 1994.
21. Huang, M. T., Deschner, E. E., Newmark, H. L., Wang, Z-Y., Ferraro, T. A., and
Conney, A. H. Effect of dietary curcumin and ascorbyl palmitate on azoxymethane-
induced colonic epithelial cell proliferation and focal areas of dysplasia. Cancer Lett.,
64: 117–121, 1992.
22. Rao, C. V., Simi, B., and Reddy, B. S. Inhibition by dietary curcumin of azoxymeth-
ane-induced ornithine decarboxylase, tyrosine protein kinase, arachidonic acid me-
tabolism and aberrant crypt foci formation in the rat colon. Carcinogenesis (Lond.),
14: 2219–2225, 1993.
23. Pereira, M. A. Grubbs, D. J., Barnes, L. H., Li, H., Olson, G. R., Eto, I., Juliana, M.,
Whitaker, L. M., Kelloff, G. J., Steele, V. E., and Lubet, R. A. Effects of the
phytochemicals, curcumin and quercetin, upon azoxymethane-induced colon cancer
and 7,12-dimethylbenz[a]anthracene-induced mammary cancer in rats. Carcinogene-
sis (Lond.), 17: 1305–1311, 1996.
24. Rao, C. V., Rivenson, A., Simi, B., and Reddy, B. S. Chemoprevention of colon
carcinogenesis by dietary curcumin, a naturally occurring plant phenolic compound.
Cancer Res., 55: 259–266, 1995.
25. Reddy, B. S., Rao, C. V., Rivenson, A., and Kelloff, G. Inhibitory effect of aspirin on
azoxymethane-induced colon carcinogenesis in F344 rats. Carcinogenesis (Lond.),
14: 1493–1497, 1993.
26. Rao, C. V., Rivenson, A., Simi, B., Zang, E., Kelloff, G., Steele, V., and Reddy, B. S.
Chemoprevention of colon carcinogenesis by sulindac, a nonsteroidal anti-inflamma-
tory agent. Cancer Res., 55: 1464–1472, 1995.
27. Rao, C. V., Tokumo, K., Rigotty, J., Zang, E., Kelloff, G., and Reddy, B. S.
Chemoprevention of colon carcinogenesis by dietary administration of piroxicam,
a
-difluoromethylornithine, 16
a
-fluoro-5-androsten-17-one, and ellagic acid individ-
ually and in combination. Cancer Res., 51: 45284534, 1991.
28. Boolbol, S. K., Dannenberg, A. J., Chadburn, A., Martucci, C., Guo, X., Ramonettti,
J. T., Abreu-Goris, M., Newmark, H. L., Lipkin, M. L., DeCosse, J. J., and Bertag-
nolli, M. M. Cyclooxygenase-2 overexpression and tumor formation are blocked by
sulindac in a murine model of familial adenomatous polyposis. Cancer Res., 56:
2556–2560, 1996.
29. Samaha, H. S., Hamid, R., El-Bayoumy, K., Rao, C. V., and Reddy, B. S. The role
of apoptosis in the modulation of colon carcinogenesis by dietary fat and by the
organoselenium compound 1,4-phenylenebis(methylene)selenocyanate. Cancer Epi-
demiol. Biomark. Prev., 6: 699–704, 1997.
30. Bedi, A., Pasricha, P. J., Akhtar, A. J., Barber, J. P., Bedi, G. C, Giardiello, G. M.,
Zehnbauer, B. A., Hamilton, S. R., and Jones, R. J. Inhibition of apoptosis during
development of colorectal cancer. Cancer Res., 55: 1811–1816, 1995.
31. Schultz-Osthoff, K., Wakzcak, H., Droge, W., and Krammer, P. H. Cell nucleus and
DNA fragmentation are not required for apoptosis. J. Cell Biol., 127: 15–20, 1994.
32. Collins, R. J., Harmon, B. V., Gobi, G. C., and Kerr, J. F. R. Internucleosomal DNA
cleavage should not be the sole criterion for identifying apoptosis. Int. J. Radiat. Biol.,
61: 451–453, 1992.
33. Schulte-Herman, R., Buisch, W., and Grasl-Krupp, B. Active cell death (apoptosis) in
liver biology and disease. In: J. L. Boyer and R. D. Ockner (eds.), Progress in Liver
Diseases, Vol. 13, pp. 1–35. Philadelphia: W. B. Saunders, 1995.
34. Kerr, J. F. R., Wyllie, A. H., and Currie, A. R. Apoptosis: basic biological phenom-
enon with wide-ranging implication in tissue kinetics. Br. J. Cancer, 26: 239–257,
1972.
35. Hall, P., Coates, P. J., Ansari, B, and Hopwood, D. Regulation of cell number in the
mammalian gastrointestinal tract: the importance of apoptosis. J. Cell Sci., 107:
3569–3577, 1994.
36. Samaha, H. S., Kelloff, G. J., Steele, V., Rao, C. V., and Reddy, B. S. Modulation of
apoptosis by sulindac, curcumin, phenylethyl-3-methylcaffeate, and 6-phenylhexyl
isothiocyanate: apoptotic index as a biomarker in colon cancer chemoprevention and
promotion. Cancer Res., 57: 1301–1305, 1997.
37. Reddy, B. S., Maruyama, H., and Kelloff, G. Dose-related inhibition of colon
carcinogenesis by dietary piroxicam, a nonsteroidal anti-inflammatory drug, during
different stages of rat colon tumor development. Cancer Res., 47: 5340–5346, 1987.
38. Honn, K. V., Grossi, I. M., Steinert, B. W., Chopra, H., Onoda, J., Nelson, K. K., and
Taylor, J. D. Lipoxygenase regulation of membrane expression of tumor cell glyco-
proteins and subsequent metastasis. Adv. Prostaglandin Thromboxane Leukotriene
Res., 19: 439443, 1989.
39. Timar, J., Chen, Y. Q., Liu, B., Basaz, R., Taylor, J. D., and Honn, K. V. The
lipoxygenase metabolite 12(S)-HETE promotes
a
IIb
b
3 integrin-mediated tumor-cell
spreading on fibronectin. Int. J. Cancer, 52: 594603, 1992.
40. Honn, K. V., and Tang, D. G. Adhesion molecules and cancer cell interaction with
endothelium and subendothelial matrix. Cancer Metastasis Rev., 11: 353–375, 1992.
41. Furstenberger, G., Schurich, B., Kaina, B., Petrusevska, R. T., Fusenig, N. E., and
Marks, F. Tumor induction in initiated mouse skin by phorbol esters and methyl-
methanesulfonate: correlation between chromosomal damage and conversion (“stage
I of tumor promotion”) in vivo. Carcinogenesis (Lond.). 10: 749–752, 1989.
42. Jiang, M. C., Yang-Yen, H. F. J., Yen, J. J., and Lin, J. K. Curcumin induces apoptosis
in immortalized NIH 3T3 and malignant cancer cell lines. Nutr. Cancer, 26: 111–120,
1996.
43. Xu, Y. X., Pindolia, K. R., Janakiraman, N., Chapman, N., and Gautam S. C.
Curcumin inhibits IL-1
a
and TNF-
a
induction of AP-1 and NF-
k
B DNA-binding
activity in bone marrow stromal cells. Hematopathol. Mol. Hematol., 11: 4962,
1997–1998.
44. Piantadosi, S., Hamilton, S. R., and Giardiello, F. M. The effects of sulindac on
colorectal proliferation and apoptosis in familial adenomatous polyposis. Gastroen-
terology, 109: 994–998, 1995.
45. Elder, D. J. E., Hague, A., Hicks, D. J., and Paraskeva, C. Differential growth
inhibition by the aspirin metabolite salicylate in human colorectal tumor cell lines:
enhanced apoptosis in carcinoma and in vitro-transformed adenoma relative to ade-
noma cell lines. Cancer Res., 56: 2273–2276, 1996.
601
CHEMOPREVENTIVE EFFECT OF CURCUMIN
on June 4, 2013. © 1999 American Association for Cancer Research. cancerres.aacrjournals.org Downloaded from
... One of the nutritional compounds associated with tumor inhibition and regression is curcumin, the main active ingredient of Curcuma longa plant extract [10][11][12]. These effects are believed to occur through tumor protein p53 (p53 or TP53), serine/threonine kinases (AKT), rat sarcoma virus (Ras), Wnt-β catenin, mammalian target of rapamycin (mTOR), and phosphatidylinositol 3-kinases (PI3K) signal pathways [13]. ...
Article
Full-text available
Background We investigated the apoptotic effects of curcumin in the colon carcinoma cell line SW480.Methods and resultsCells were treated with 40–200 μM curcumin for 24, 48, and 72 h, and the IC50 values were determined for each time interval. BrdU, caspase-3, and TUNEL staining results and the gene expression of FADD, CASP8, and CASP3 were evaluated. Curcumin treatments significantly inhibited cell proliferation and significantly induced apoptosis for 24, 48, and 72 h. The proportion of BrdU-stained cells in the control groups were 58%, 57% and 61% and 28%, 27%, and 30% in the curcumin treatment groups at 24, 48, and 72 h, respectively. The proportion of apoptotic cells was 28%, 29%, and 28% in the control groups and 59%, 61%, and 60% in the curcumin treatment groups at 24, 48, and 72 h, respectively. As expected, caspase-3 staining also revealed a higher number of apoptotic cells in curcumin treatment groups at 24, 48, and 72 h compared to controls. The proportion of Caspase-3-stained cells in the control groups were 23%, 25%, and 24% and 59%, 60%, and 62% in the curcumin treatment groups at 24, 48, and 72 h, respectively. To prove caspase-3 staining results, FADD, CASP8, and CASP3 gene expressions were evaluated by real-time qPCR. Unlike the immunohistochemical results, no statistically significant upregulation was found at 24 and 48 h, while relative gene expressions of FADD, CASP8, and CASP3 was significantly upregulated at 72 h. The expression level increase was 0.88-, 1.19-, and 2.11-fold for FADD, 1.25-, 1.29-, and 1.59-fold for CASP8, and 1.33-, 1.46-, and 3.00-fold for CASP3 at 24, 48, and 72 h, respectively. Conclusions These results suggest that curcumin may be a potential protective or treatment agent against colon cancer; however, further studies on curcumin-rich diets and curcumin bioavailability are required.Graphical abstract
... It is a yellow pigment from Curcuma longa. Its anticancer activity was reported in various types of cancers such as ovarian, lung, breast, and melanoma [22][23][24][25][26][27]. However, the mechanism of anticancer action of CUR is not fully understood; some studies showed it kills cancer cells by induction of apoptosis [26,27]. ...
Article
Full-text available
Curcumin (CUR) has interesting properties to cure cancer. Cold atmospheric plasma (CAP) is also an emerging biomedical technique that has great potential for cancer treatment. Therefore, the combined effect of CAP and CUR on inducing cytotoxicity and apoptosis of melanoma cancer cells might be promising. Here, we investigated the combined effects of CAP and CUR on cytotoxicity and apoptosis in B16-F10 melanoma cancer cells compared to L929 normal cells using MTT method, acridine orange/ethidium bromide fluorescence microscopic assay, and Annexin V/PI flow cytometry. In addition, the activation of apoptosis pathways was evaluated using BCL2, BAX, and Caspase-3 (CASP3) gene expression and ratio of BAX to BCL2 (BAX/BCL2). Finally, in silico study was performed to suggest the molecular mechanism of this combination therapy on melanoma cancer. Results showed that although combination therapy with CUR and CAP has cytotoxic and apoptotic effects on cancer cells, it did not improve apoptosis rate in melanoma B16-F10 cancer cells compared to monotherapy with CAP or CUR. In addition, evaluation of gene expression in cancer cell line confirmed that CUR and CAP concomitant treatment did not enhance the expression of apoptotic genes. In silico analysis of docked model suggested that CUR blocks aquaporin- (AQP-) 1 channel and prevents penetration of CAP-induced ROS into the cells. In conclusion, combination therapy with CAP and CUR does not improve the anticancer effect of each alone.
... In recent years, curcumin has been increasingly recognized for its anti-tumor and chemopreventive properties, especially in gastrointestinal tumors (Huminiecki, Horbanczuk & Atanasov, 2017). For example, curcumin has shown chemopreventive effects in animal models of colon cancer (Kawamori et al., 1999), stomach cancer (Huang et al., 1994), and HCC (Chuang et al., 2000). Curcumin has been reported to decrease cell growth and induce apoptosis mainly through the inhibition of nuclear factor kappa-B (NFκB) (Ghasemi et al., 2019). ...
Article
Full-text available
Background The anti-tumor properties of curcumin have been demonstrated for many types of cancer. However, a systematic functional and biological analysis of its target proteins has yet to be fully documented. The aim of this study was to explore the underlying mechanisms of curcumin and broaden the perspective of targeted therapies. Methods Direct protein targets (DPTs) of curcumin were searched in the DrugBank database. Using the STRING database, the interactions between curcumin and DPTs and indirect protein targets (IPTs) weres documented. The protein–protein interaction (PPI) network of curcumin-mediated proteins was visualized using Cytoscape. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was performed for all curcumin-mediated proteins. Furthermore, the cancer targets were searched in the Comparative Toxicogenomics Database (CTD). The overlapping targets were studied using Kaplan–Meier analysis to evaluate cancer survival. Further genomic analysis of overlapping genes was conducted using the cBioPortal database. Lastly, MTT, quantitative polymerase chain reaction (qPCR), and western blot (WB) analysis were used to validate the predicted results on hepatocellular carcinoma (HCC) cells. Results A total of five DPTs and 199 IPTs were found. These protein targets were found in 121 molecular pathways analyzed via KEGG enrichment. Based on the anti-tumor properties of curcumin, two pathways were selected, including pathways in cancer (36 genes) and HCC (22 genes). Overlapping with 505 HCC-related gene sets identified in CTD, five genes (TP53, RB1, TGFB1, GSTP1, and GSTM1) were finally identified. High mRNA levels of TP53, RB1, and GSTM1 indicated a prolonged overall survival (OS) in HCC, whereas elevated mRNA levels of TGFB1 were correlated with poor prognosis. The viability of both HepG2 cells and Hep3B cells was significantly reduced by curcumin at concentrations of 20 or 30 μM after 48 or 72 h of culture. At a concentration of 20 μM curcumin cultured for 48 h, the expression of TGFB1 and GSTP1 in Hep3B cells was reduced significantly in qPCR analysis, and reduced TGFB1 protein expression was also found in Hep3B cells.
... Otherwise, oral curcumin has been shown to also inhibit xenograftinduced skin tumors [18,19] and chemically-induced tumors in other organs such as colon in rodents [20,21] . In addition to oral or topical administration, curcumin can be administered subcutaneously, intravenously, intraperitoneally with more or less satisfactory results [22] . ...
Article
Turmeric is a yellow powder from the rhizomes of a herbaceous plant, Curcuma longa. Curcumin, a major component of turmeric, is a polyphenol that has anti-oxidant, anti-inflammatory and antiproliferative properties that give it an antitumor effect. Administration of oral curcumin appears few effective because of its low bioavailability but adjuvants such as piperine present in black pepper may improve this bioavailability. The aim of the present study is the evaluation the effect of curcumin and piperine-based regimen on the development and growth of chemo-induced cutaneous tumors in Swiss albino mice. A single topical application of 400 nmol of DMBA (7,12-dimethylbenz (a) anthracene) is followed one week later by the application twice a week of 5 nmol of TPA (12-O-tetradecanoylphorbol-13-acetate) during 10 weeks. DMBA/TPA-induced papillomas are evaluated in mice fed a standard diet or curcumin (0.5%) and piperine (0.005%) diet. Curcumin significantly inhibited the tumorigenic effect of DMBA and TPA by decreasing tumor incidence by 50%, tumor multiplicity by 38% and tumor volume by 90%. In addition, the histological study showed that the curcumin and piperine diet attenuated epidermal changes caused by DMBA/TPA treatment such as hyperplasia, cellular atypia and hyperkeratosis. Our study demonstrated that oral co-administration of curcumin and piperine has a significant inhibitory effect on DMBA/TPA-induced cutaneous tumorigenesis. Piperine, by increasing the bioavailability of curcumin, improves its chemoprotective and chemo-preventive efficacy against tumor development.
... Efforts have also been made in preventing chemical carcinogenesis: e.g., in a rat model of mammary carcinogenesis by dimethylbenz[a]anthracene, post treatment with a NSAID ibuprofen or celecoxib could not only delay the occurrence of the tumor but also reduce the tumor incidence by half or more (Harris et al. 2000). In another rat model of colon carcinogenesis by azoxymethane (AOM), curcumin (Kawamori et al. 1999), or a NSAID piroxicum (Reddy et al. 1987), sulindac (Rao et al. 1995), celecoxib (Reddy et al. 2000(Reddy et al. , 2005, or naproxen in combination with atorvastatin (Suh et al. 2011) were able to reduce the tumor incidence when they were administered 1 day to more than 10 weeks after the AOM treatment. More recently, in a mouse model of tumor therapy, it was reported that a pre-operative administration of NSAID and/ or resolvins could attenuate surgery-or chemotherapyinduced dormancy escape and increases the survival time of the animals (Panigrahy et al. 2019;Fishbein, Hammock, et al. 2020, Fishbein, Wang, et al. 2020. ...
Article
Full-text available
[Purpose] Ionizing radiation is a well-known carcinogen, and epidemiologic efforts have been made to evaluate cancer risks following a radiation exposure. The basic approach has been to estimate increased levels of cancer mortality resulting from exposures to radiation, which is consistent with the somatic mutation theory of cancer. However, the possibility that an irradiation might cause an earlier onset of cancer has also been raised since the earliest days of animal studies. Recently, the mutation induction model has been challenged because it is unable to explain the observed dose-related parallel shift of entire mouse survival curves toward younger ages following an irradiation. This is because if it is assumed that only a fraction of the irradiated individuals are affected, the irradiated population would consist of two subpopulations with different mean lifespans, which makes the overall distribution of individual lifespans broader, and hence the slope of the survival curves shallower. To explain this parallel shift, it is necessary to assume that all individuals of a population are affected. As a result of these observations, possible mechanisms which could account for the parallel shift of mouse survival curves were sought by examining the radiation induction of various types of tissue damage which could facilitate an earlier onset of spontaneously arising cancers. [Conclusion] A proposed mechanism postulates that a radiation exposure leads to tissue inflammation which subsequently stimulates spontaneously arising cancers and allows them to appear earlier than usual. This notion is not unprecedented, and because the background incidence of cancer increases exponentially with an increase in age, a slight shift of the onset age toward younger ages may make it appear as if the risk is increased. In this scenario, a radiation exposure induces DNA damage, cell death, chromosome aberrations etc., which leads to the multi-pathway responses including activation of stromal fibroblasts, macrophages and various inflammatory factors. Such an inflamed microenvironment favors the growth of spontaneously arising tumor cells although currently, the sequential order or relative importance of the individual factors remains to be known. Biographical Note Nori Nakamura PhD, is a radiation biologist and geneticist working at the Radiation Effects Research Foundation in Hiroshima, Japan, for more than 35 years. He is also interested in biodosimetry methods which include cytogenetic methods and the electron-spin (paramagnetic)-resonance method used to examine tooth enamel.
Article
Full-text available
RESUMO: Este estudo objetivou ampliar um novo modelo de controle e monitoramento microbiológico e de boas práticas no pé e pós-cultivo da planta medicinal, Curcuma longa nos estágios da matéria prima até o produto final. Foram avaliadas microbiologicamente 144 amostras de três agricultores de Vargem Grande, Pau da Fome e Queimados no Estado do Rio de Janeiro. As pesquisas realizadas foram a verificação da capacidade inibitória, a determinação do número total de bactérias aeróbicas, bolores e leveduras; bactérias Gram-negativas bile tolerantes e os micro-organismos patogênicos. Após o estabelecimento de pontos críticos e orientações das boas práticas em todas as fases do processo, foram tomadas medidas preventivas e corretivas. Das amostras analisadas 86% estavam insatisfatórias em todas as fases. Após o estabelecimento de pontos críticos e tomadas medidas preventivas e corretivas em todas as fases do processo, conforme as boas práticas, os resultados demonstraram que houve melhoria da qualidade dos produtos segundo os limites microbiológicos estabelecidos pela OMS e Farmacopeia Brasileira Palavras-chave: plantas medicinais; fitoterápico; qualidade microbiológica; Vigilância Sanitária. ABSTRACT: Microbiological quality determination of the curcuma longa from raw material until o final product: monitoring model. This study aimed to expand a new model of control and microbiological monitoring and good practices in pre and post cultivation of the medicinal plant Curcuma longa in stages from the raw material to the finished product. One hundred forty four samples of five farmers from Vargem Grande, Pau da Fome e Queimados in the state of Rio de Janeiro-Brazil. The researches performed were: inhibitory capacity verification, determination of the total number of aerobic bacteria, yeasts and molds; bile-tolerant Gram-negative bacteria and pathogenic microorganisms. After the establishment of critical points and good practice guidance at all stages of the process, preventive and corrective measures were taken. From the samples 86% were unsatisfactory in all phases. After the preventive and corrective measures taken to remedy the critical points, the results were satisfactory in most of the samples. After the establishment of critical points and implementation of preventive and corrective measures at all stages of the process, according to good practice, our results showed an improvement of product quality, according to the microbiological limits established by WHO and the Brazilian Pharmacopoeia.
Article
Full-text available
Reactive oxygen species (ROS) play an important role in cellular metabolism. Many chemotherapeutic drugs are known to promote apoptosis through the production of ROS. In the present study, the novel curcumin derivative, 1g, was found to inhibit tumor growth in colon cancer cells both in vitro and in vivo. Bioinformatics was used to analyze the differentially expressed mRNAs. The mechanism of this effect was a change in mitochondrial membrane potential caused by 1g that increased its pro-apoptotic activity. In addition, 1g produced ROS, induced G1 checkpoint blockade, and enhanced endoplasmic reticulum (ER)-stress in colon cancer cells. Conversely, pretreatment with the ROS scavenging agent N-acetyl-l-cysteine (NAC) inhibited the mitochondrial dysfunction caused by 1g and reversed ER-stress, cell cycle stagnation, and apoptosis. Additionally, pretreatment with the p-PERK inhibitor GSK2606414 significantly reduced ER-stress and reversed the apoptosis induced by colon cancer cells. In summary, the production of ROS plays an important role in the destruction of colon cancer cells by 1g and demonstrates that targeted strategies based on ROS represent a promising approach to inhibit colon cancer proliferation. These findings reveal that the novel curcumin derivative 1g represents a potential candidate therapeutics for the treatment of colon cancer cells, via apoptosis caused by mitochondrial dysfunction and endoplasmic reticulum stress.
Article
Full-text available
Dietary compounds play an important role in the prevention and treatment of many cancers, although their specific molecular mechanism is not yet known. In the present study, thirty dietary agents were analyzed on nine drug targets through in silico studies. However, nine dietary scaffolds, such as silibinin, flavopiridol, oleandrin, ursolic acid, α-boswellic acid, β-boswellic acid, triterpenoid, guggulsterone, and oleanolic acid potentially bound to the cavity of PI3K-α, PKC-η, H-Ras, and Ras with the highest binding energy. Particularly, the compounds silibinin and flavopiridol have been shown to have broad spectrum anticancer activity. Interestingly, flavopiridol was embedded in the pockets of PI3K-α and PKC-η as bound crystal inhibitors in two different conformations and showed significant interactions with ATP binding pocket residues. However, complex-based pharmacophore modeling achieved two vital pharmacophoric features namely, two H-bond acceptors for PI3K-α, while three are hydrophobic, one cat-donor and one H-bond donor and acceptor for PKC-η, respectively. The database screening with the ChemBridge core library explored potential hits on a valid pharmacophore query. Therefore, to optimize perspective lead compounds from the hits, which were subjected to various constraints such as docking, MM/GBVI, Lipinski rule of five, ADMET and toxicity properties. Henceforth, the top ligands were sorted out and examined for vital interactions with key residues, arguably the top three promising lead compounds for PI3K-α, while seven for PKC-η, exhibiting binding energy from − 11.5 to − 8.5 kcal mol ⁻¹ . Therefore, these scaffolds could be helpful in the development of novel class of effective anticancer agents.
Article
Ion channels are ubiquitously expressed in almost all living cells, and are the third-largest category of drug targets, following enzymes and receptors. The transient receptor potential melastatin (TRPM) subfamily of ion channels are important to cell function and survival. Studies have shown upregulation of the TRPM family of ion channels in various brain tumours. Gliomas are the most prevalent form of primary malignant brain tumours with no effective treatment; thus, drug development is eagerly needed. TRPM2 is an essential ion channel for cell function and has important roles in oxidative stress and inflammation. In response to oxidative stress, ADP-ribose (ADPR) is produced, and in turn activates TRPM2 by binding to the NUDT9-H domain on the C-terminal. TRPM2 has been implicated in various cancers and is significantly upregulated in brain tumours. This article reviews the current understanding of TRPM2 in the context of brain tumours and overviews the effects of potential drug therapies targeting TRPM2 including hydrogen peroxide (H2O2), curcumin, docetaxel and selenium, paclitaxel and resveratrol, and botulinum toxin. It is long withstanding knowledge that gliomas are difficult to treat effectively, therefore investigating TRPM2 as a potential therapeutic target for brain tumours may be of considerable interest in the fields of ion channels and pharmacology.
Article
The effects of topical applications of very low doses of curcumin (the major yellow pigment in turmeric and the Indian food curry) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced oxidation of DNA bases in the epidermis and on tumor promotion in mouse skin were investigated. CD-1 mice were treated topically with 200 nmol of 7,12-dimethylbenz[a]anthracene followed one week later by 5 nmol of TPA alone or together with 1, 10, 100 or 3000 nmol of curcumin twice a week for 20 weeks. Curcumin-mediated effects on TPA-induced formation of the oxidized DNA base 5-hydroxymethyl-2'-deoxyuridine (HMdU) and tumor formation were determined. All dose levels of curcumin inhibited the mean values of TPA-induced HMdU formation in epidermal DNA (62-77% inhibition), but only the two highest doses of curcumin strongly inhibited TPA-induced tumor promotion (62-79% inhibition of tumors per mouse and tumor volume per mouse). In a second experiment, topical application of 20 or 100 nmol (but not 10 nmol) of curcumin together with 5 nmol TPA twice a week for 18 weeks markedly inhibited TPA-induced tumor promotion. Curcumin had a strong inhibitory effect on DNA and RNA synthesis (IC 50 ) = 0.5-1 μM) in cultured HeLa cells, but there was little or no effect on protein synthesis.
Article
This is an epidemiological study of 107 patients with large bowel cancer and 307 control patients interviewed in Japan. Colon cancer is significantly less common in Japan, but rectal cancer is as common in Japan as it is in the United States. Japanese patients with cancer of the colon have a higher socioeconomic status than rectal cancer patients. Associated with the higher status is a more Western style diet. It is suggested that perhaps dietary fat influences the make-up of the bacterial flora and thus affects the pathogenesis of cancer of the colon. No significant relationship was found to medical and surgical diseases nor to the cholesterol and weight levels.
Article
Apoptosis is the predominant form of cell death and occurs under a variety of physiological and pathological conditions. Cells undergoing apoptotic cell death reveal a characteristic sequence of cytological alterations including membrane blebbing and nuclear and cytoplasmic condensation. Activation of an endonuclease which cleaves genomic DNA into internucleosomal DNA fragments is considered to be the hallmark of apoptosis. However, no clear evidence exists that DNA degradation plays a primary and causative role in apoptotic cell death. Here we show that cells enucleated with cytochalasin B still undergo apoptosis induced either by treatment with menadione, an oxidant quinone compound, or by triggering APO-1/Fas, a cell surface molecule involved in physiological cell death. Incubation of enucleated cells with the agonistic monoclonal anti-APO-1 antibody revealed the key morphological features of apoptosis. Moreover, in non-enucleated cells inhibitors of endonuclease blocked DNA fragmentation, but not cell death induced by anti-APO-1. These data suggest that DNA degradation and nuclear signaling are not required for induction of apoptotic cell death.
Article
Tumor-cell interaction with the vessel wall during metastasis involves adhesion, induction of endothelial-cell retraction and spreading on the exposed sub-endothelial matrix. The signals for initiation of tumor-cell spreading and the receptors involved are unknown. A protocol was developed to distinguish between initial tumor-cell (B16 amelanotic melanoma; B16a) adhesion to and spreading on fibronectin. The time for maximum spreading was 50 min. Treatment with a lipoxygenase metabolite of arachidonic acid [12(S)-HETE] resulted in maximum spreading in 15 min (max. effect approx. O.1 μM). Other lipoxygenase metabolites were ineffective. 12(S)-HETE treatment induced a rearrangement of F-actin, vinculin, vimentin intermediate filaments and integrin α11bβ3, but not integrin α5β1. Antibodies to α11bβ3 but not α5β1 blocked the 12(S)-HETE effect on B16a spreading. B16a-cell attachment to fibronectin resulted in increased metabolism of arachidonic acid to 12(S)-HETE, which was inhibited by lipoxygenase but not by cyclo-oxygenase inhibitors. Accordingly, lipoxygenase inhibitors but not cyclo-oxygenase inhibitors blocked spontaneous B16a-cell spreading. The protein-kinase-C inhibitors calphostin C, H7 and staurosporine also inhibited spreading, while the protein-kinase-A inhibitor H8 was ineffective. These data suggest that B16a-cell spreading on fibronectin is initiated by a lipoxygenase metabolite [12(S)-HETE] of arachidonic acid and is mediated by protein kinase C. © 1992 Wiley-Liss, Inc.
Article
Evidence is presented that questions the validity of using DNA electrophoresis in isolation for identifying apoptosis.
Article
Tumor-cell interaction with the vessel wall during metastasis involves adhesion, induction of endothelial-cell retraction and spreading on the exposed sub-endothelial matrix. The signals for initiation of tumor-cell spreading and the receptors involved are unknown. A protocol was developed to distinguish between initial tumor-cell (B16 amelanotic melanoma; B16a) adhesion to and spreading on fibronectin. The time for maximum spreading was 50 min. Treatment with a lipoxygenase metabolite of arachidonic acid [12(S)-HETE] resulted in maximum spreading in 15 min (max. effect approx. 0.1 microM). Other lipoxygenase metabolites were ineffective. 12(S)-HETE treatment induced a rearrangement of F-actin, vinculin, vimentin intermediate filaments and integrin alpha IIb beta 3, but not integrin alpha 5 beta 1. Antibodies to alpha IIb beta 3 but not alpha 5 beta 1 blocked the 12(S)-HETE effect on B16a spreading. B16a-cell attachment to fibronectin resulted in increased metabolism of arachidonic acid to 12(S)-HETE, which was inhibited by lipoxygenase but not by cyclo-oxygenase inhibitors. Accordingly, lipoxygenase inhibitors but not cyclo-oxygenase inhibitors blocked spontaneous B16a-cell spreading. The protein-kinase-C inhibitors calphostin C, H7 and staurosporine also inhibited spreading, while the protein-kinase-A inhibitor H8 was ineffective. These data suggest that B16a-cell spreading on fibronectin is initiated by a lipoxygenase metabolite [12(S)-HETE] of arachidonic acid and is mediated by protein kinase C.
Article
The effects of topical administration of curcumin on the formation of benzo[a]pyrene (B[a]P)–DNA adducts and the tumorigenic activities of B[a]P and 7,12-dimethyl-benz[a]anthracene (DMBA) in epidermis were evaluated in female CD-1 mice. Topical application of 3 or 10 μmol curcumin 5 min prior to the application of 20 nmol [3H]B[a]P inhibited the formation of [3H]B[a]P—DNA adducts in epidermis by 39 or 61% respectively. In a two-stage skin tumorigenesis model, topical application of 20 nmol B[a]P to the backs of mice once weekly for 10 weeks followed a week later by promotion with 15 nmol 12-O-tetradecanoylpborbol-13-acetate (TPA) twice weekly for 21 weeks resulted in the formation of 7.1 skin tumors per mouse, and 100% of the mice had tumors. In a parallel group of mice, in which the animals were treated with 3 or 10 μmol curcumin 5 min prior to each application of B[a]P, the number of tumors per mouse was decreased by 58 or 62% respectively. The percentage of tumor-bearing mice was decreased by 18–25%. In an additional study, topical application of 3 or 10 μmol curcumin 5 min prior to each application of 2 nmol DMBA once weekly for 10 weeks followed a week later by promotion with 15 nmol TPA twice weekly for 15 weeks decreased the number of tumors per mouse by 37 or 41% respectively.
Article
Cancer metastasis poses the greatest challenge to the eradication of malignancy. The majority of clinical and experimental evidence indicates that metastasis is a non-random, organ-specific process. Tumor cell interaction with endothelium and subendothelial matrix constitutes the most crucial factor in determining the organ preference of metastasis. A plethora of cell surface adhesion molecules, which encompass four major families (i.e., integrins, cadherins, immunoglobulins and selectins) and many other unclassified molecules, mediate tumor-host interactions. Adhesion molecules and adhesion processes are involved in most, if not all, of the intermediate steps of the metastatic cascade. Decreased E-cadherin expression and increased CD44 expression are clearly correlated with the acquisition of the invasive capacity of primary tumor cells. Similarly, altered expression pattern of many other adhesion molecules such as upregulated expression of the laminin receptors and depressed expression of fibronectin receptors (alpha 5 beta 1) appears to be involved in tumor cell invasion into the subendothelial matrix. Tumor cell-endothelium interactions involve several well-defined sequential steps that can be analyzed by the 'Docking and Locking' hypothesis at the molecular level. Tumor cell-matrix interactions are determined by the repertoire of adhesion receptors of tumor cells and the unique composition of organ-specific matrices. Our experimental data, together with others', suggest that the integrin alpha IIb beta 3 is one of the major players in these tumor-host interactions. Tumor-host interaction is a dynamic process which is constantly modulated by a host of factors including various cytokines, growth factors and arachidonate metabolites such as 12(S)-HETE. Delineation of the molecular mechanisms of tumor-host interactions may provide additional means to intervene in the metastatic process.