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DOX-loaded pH-sensitive mesoporous silica nanoparticles coated with PDA and PEG induce pro-death autophagy in breast cancer


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The development of multifunctional nano drug delivery carriers has been one of the most effective and prevailing approaches to overcome drug non-selectivity, low cell uptake efficiency and various side effects of traditional chemotherapy drugs. Herein, we report a novel doxorubicin (DOX)-loaded mesoporous silica nanoparticle (MSN) coated with polydopamine (PDA) and polyethylene glycol (PEG) (MSNs-DOX@PDA-PEG) for the treatment of breast cancer. In this system, PDA functions as a pH-sensitive gatekeeper to control the release of DOX from MSNs in response to pH-stimulus and PEG was further grafted on the surface of PDA to increase the stability and biocompatibility under physiological conditions. The in vitro release results suggested that MSNs-DOX@PDA-PEG exhibits a high sensitivity to low pH. A cellular uptake assay showed a high cellular uptake efficiency of MSNs-DOX@PDA-PEG compared to free DOX. Furthermore, MSNs-DOX@PDA-PEG also demonstrated an improved anti-cancer efficacy compared to free DOX both in vivo and vitro breast cancer experiments. Mechanistic studies revealed that MSNs-DOX@PDA-PEG causes a stronger pro-death autophagy compared to free DOX via inhibition of the AKT-mTOR-p70S6K signaling pathway. Taken in concert, our results suggest that the novel material MSNs-DOX@PDA-PEG may represent a promising nanoformulation for breast cancer treatment.
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DOX-loaded pH-sensitive mesoporous silica
nanoparticles coated with PDA and PEG induce
pro-death autophagy in breast cancer
Yanhong Duo,
Yang Li,
Changke Chen,
Baiyun Liu,
Xinyu Wang,*
Xiaowei Zeng *
and Hongbo Chen*
The development of multifunctional nano drug delivery carriers has been one of the most eective and
prevailing approaches to overcome drug non-selectivity, low cell uptake eciency and various side
eects of traditional chemotherapy drugs. Herein, we report a novel doxorubicin (DOX)-loaded
mesoporous silica nanoparticle (MSN) coated with polydopamine (PDA) and polyethylene glycol (PEG)
(MSNs-DOX@PDA-PEG) for the treatment of breast cancer. In this system, PDA functions as a pH-
sensitive gatekeeper to control the release of DOX from MSNs in response to pH-stimulus and PEG was
further grafted on the surface of PDA to increase the stability and biocompatibility under physiological
conditions. The in vitro release results suggested that MSNs-DOX@PDA-PEG exhibits a high sensitivity to
low pH. A cellular uptake assay showed a high cellular uptake eciency of MSNs-DOX@PDA-PEG
compared to free DOX. Furthermore, MSNs-DOX@PDA-PEG also demonstrated an improved anti-
cancer ecacy compared to free DOX both in vivo and vitro breast cancer experiments. Mechanistic
studies revealed that MSNs-DOX@PDA-PEG causes a stronger pro-death autophagy compared to free
DOX via inhibition of the AKT-mTOR-p70S6K signaling pathway. Taken in concert, our results suggest
that the novel material MSNs-DOX@PDA-PEG may represent a promising nanoformulation for breast
cancer treatment.
Breast cancer represents a leading cause of death among
Presently, chemotherapy is one of the main available
treatment options for breast cancer. However, traditional
chemotherapeutic treatments oen result in drug resistance
and frequently cause harmful side eects to non-cancerous
tissues due to the lack of selective tumor targeting.
Doxorubicin (DOX) is one of the most ecient anticancer
drugs that is widely used for the treatment of multiple cancer
types including breast, bladder, lung, hematological malig-
nancies, and others.
As an anthracycline antibiotic, DOX can
interfere with DNA synthesis, induce DNA damages, produce
reactive oxygen species, and destroy membrane structures.
Recently, the development of a safe and ecient drug delivery
system to deliver DOX to the tumor site attracted a signicant
amount of attention in the scientic community. With the
development of nanotechnology, nanoformulations have been
widely employed for the delivery of anticancer drugs. However,
drug release from polymer-based nanoparticles takes place
mainly through diusion and/or polymer degradation.
latter represents a slow process and the therapeutic drug levels
may therefore not promptly reach an eective drug concentra-
tion. Recently, mesoporous silica nanoparticles (MSNs) have
attracted enormous attention in the eld of drug delivery due to
their unique physiochemical properties, including large surface
area and pore volume, tunable particle/pore size, high drug
loading eciency, easy surface modication and remarkable
stability and biocompatibility.
By modifying the outer surface
of MSNs with various functional groups such as polymers,
quantum dots,
or/and by using
a combination with other nanomaterials,
and active targeting nanosystems can be designed for the tar-
geted delivery of anticancer drugs.
In this study, we developed DOX-loaded mesoporous silica
nanoparticles (MSN) and the nanoparticle surface was further
coated with polydopamine (PDA) and polyethylene glycol (PEG).
Key Laboratory of Plant Cell Activities and Stress Adaptation, Ministry of Education,
School of Life Sciences, Lanzhou University, Lanzhou 730000, P. R. China. E-mail:
School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Guangzhou
510275, P. R. China. E-mail:
The Shenzhen Key Lab of Gene and Antibody Therapy, Division of Life and Health
Sciences, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, P.
R. China. E-mail:
Department of Hepatobiliary and Pancreas Surgery, Second Clinical Medical College
of Jinan University, Shenzhen People's Hospital, Shenzhen 518000, P. R. China
Electronic supplementary information (ESI) available. See DOI:
These authors contribute equally to this work.
Cite this: RSC Adv.,2017,7, 39641
Received 7th May 2017
Accepted 1st August 2017
DOI: 10.1039/c7ra05135b
This journal is © The Royal Society of Chemistry 2017 RSC Adv.,2017,7, 3964139650 | 39641
RSC Advances
In this system, PDA coating not only protects DOX leakage
under physiological conditions (pH 7.4) but also allows for the
sustained-release of the drugs in an acidic environment
(pH 5.0).
PEG on the surface of MSNs ensures water solu-
bility and further prevents nonspecic interactions with bio-
Previous reports published in the literature
show that the polymer-based nanoparticles may be taken up by
cells through the endocytosis-lysosome pathway.
Thus, we
anticipated that DOX may be rapidly released when MSNs-
DOX@PDA-PEG enters to lysosomes where the pH value is
about 5.020. Furthermore, our results suggested that MSNs-
DOX@PDA-PEG exhibits improved anti-cancer abilities
compared to free DOX both in vitro and in vivo. Furthermore,
mechanistic studies revealed that MSNs-DOX@PDA-PEG may
cause a stronger pro-death autophagy compared to free DOX via
the AKT-mTOR-p70s6K signaling pathway.
Results and discussion
Synthesis and physicochemical characterization of MSNs-
MSNs-DOX@PDA-PEG was synthesized as described below in
the section Materials and methods.Theparticlesizeand
surface properties of the nanoparticlesplayimportantrolesin
drug release, cellular uptake and pharmacokinetics.
Fig. 1A
shows a schematic representation of the MSNs-DOX@PDA-
PEG synthesis. In order to access the morphology of MSNs,
was performed. Fig. 1B, C and D show representative images
respectively. As shown in Fig. 1B, the MSNs exhibit a nearly
spherical shape and porous surfaces. Compared with MSNs
(cf. Fig. 1B), MSNs-DOX@PDA (cf. Fig. 1C) and MSNs-
DOX@PDA-PEG (cf. Fig. 1D) show the PDA and PEG coating
on the MSNs surface, with a clear layer found on the periphery
of the particles.
The sizes of MSNs, MSNs-DOX, MSNs-DOX@PDA and MSNs-
DOX@PDA-PEG were determined using dynamic light scattering
(DLS). As shown in Table 1, the diameters of the MSNs, MSNs-
DOX, MSNs-DOX@PDA and MSNs-DOX@PDA-PEG were 125.34
4.42, 130.21 3.37, 170.32 2.49 and 198.75 2.56 nm,
respectively. Although the sizes of MSNs-DOX@PDA and MSNs-
DOX@PDA-PEG were slightly larger than MSNs, they were also
found to be smaller than the cut-osize of tumor neovasculature
falling within the range of easy accumulation of the
enhanced permeation and retention (EPR) eect.
The zeta potentials were also determined as shown in Table
1. The zeta potentials of MSNs, MSNs-DOX, MSNs-DOX@PDA
and MSNs-DOX@PDA-PEG were 19.43 5.21, 8.56 2.19,
12.44 3.29 and 2.11 0.97 mV, respectively. Since most
cellular membranes are negatively charged, the zeta potential
can aect the tendency of the nanoparticles to permeate
membranes, with cationic particles exhibiting a higher toxicity
with cell membrane disruption. In general, nanoparticles with
a zeta potential between 10 and +10 mV are considered
neutral. The specic surface area, pore volume and the most
probable pore size of MSNs, MSNs-DOX, MSNs-DOX@PDA and
MSNs-DOX@PDA-PEG are also shown in Table 1. Compared to
MSNs and MSNs-DOX, all pore parameters of MSNs-DOX@PDA
and MSNs-DOX@PDA-PEG were found to be signicantly
decreased. The BET surface area was 264.72 m
, the pore
volume was 0.62 cm
and, as evaluated by the BJH method,
the most probable pore size was about 2.89 nm. Moreover, the
pore size distribution of MSNs was rather narrow. With loading
of DOX, the BET surface area and the most probable pore size
decreased to 121.32 m
and 2.31 nm, respectively. The BET
surface area of MSNs-DOX@PDA and MSNs-DOX@PDA-PEG
was 46.73 and 49.78 m
, respectively. However, the pore
Fig. 1 (A) Schematic representation of MSNs-DOX@PDA-PEG synthesis. (B) TEM image of MSNs. (C) TEM image of MSNs-DOX@PDA. (D) TEM
image of MSNs-DOX@PDA-PEG.
39642 |RSC Adv.,2017,7, 3964139650 This journal is © The Royal Society of Chemistry 2017
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Table 1 Characterization parameters of MSNs, MSNs-DOX, MSNs-DOX@PDA and MSNs-DOX@PDA-PEG
Polymer Size
(nm) ZP (mV)
BET surface
area (m
Pore volume
Pore size
MSNs 125.34 4.42 19.43 5.21 264.72 0.62 2.89
MSNs-DOX 130.21 3.37 8.56 2.19 121.32 0.43 2.31
MSNs-DOX@PDA 170.32 4.49 12.44 3.29 46.73 0.15
MSNs-DOX@PDA-PEG 198.75 2.56 2.11 0.97 49.78 0.11
NPs size was measured by dynamic light scattering.
BJH cumulative pore volume for pores between 1.7 and 300 nm in width.
Most probable
pore size.
Fig. 2 (A) In vitro release prole of MSNs-DOX (B) in vitro release prole of MSNs-DOX@PDA-PEG.
Fig. 3 (A) Uptake of free DOX and MSNs-DOX@PDA-PEG detected by confocal microscopy in MCF10A cells (red: DOX; blue: DAPI, scale bar ¼
10 mm). (B) Same treatment as (A) but using MCF7 cells. (C) Flow cytometry (a) free DOX in MCF10A, (b) free DOX in MCF7, (c) MSNs-DOX@PDA-
PEG in MCF10A and (d) MSNs-DOX@PDA-PEG in MCF7 (a black, b blue, c rose red, d red).
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volumes were 0.15 and 0.11 cm
due to the coating of PDA
and PEG onto the surface of DOX-loaded MSNs. Overall, the
structural parameters of MSNs, MSNs-DOX, MSNs-DOX@PDA
and MSNs-DOX@PDA-PEG suggested that DOX occupied the
pore space of MSNs and DOX loaded MSNs were coated with
PDA and PEG. The encapsulation eciency of DOX in MSNs was
about 95.63 2.32.
In addition, as a result of the slightly negative charge of MSNs-
DOX@PDA-PEG, the overall clearance by the reticuloendothelial
system (RES) such as liver was found to be reduced.
data suggested that MSNs-DOX could be successfully synthesized
and modied by introduction of PDA and PEG lms.
A pH-sensitive drug release prole in vitro
Previously published research data shows that the polymer-
based nanoparticles are taken up by cells through the
endocytosis-lysosome pathway.
The pH value of lysosomes is
about 5.0, which is maintained by proton pumps on the lyso-
some membrane.
In addition, low pH conditions are also
considered a hallmark of malignant solid tumor tissues. In
order to verify the drug blocking potency and pH sensitivity of
PDA and PEG coating, we performed a drug release experiment
at pH 5.0 and pH 7.4 at dierent time intervals. As shown in
Fig. 2A, without PDA and PEG coating, DOX was quickly
released at all tested pH values, freely diusing from the pores
Fig. 4 (A, B) Viability of MCF7 and MDA-MB-231 cells cultured with MSNs@PDA-PEG, free DOX, MSNs-DOX@PDA and MSNs-DOX@PDA-PEG,
respectively, with dierent NPs concentrations after 24 h. Data were expressed as mean SD (*p< 0.05, **p< 0.01). (C, D) Cell proliferation
evaluation of MSNs@PDA-PEG, free DOX, MSNs-DOX@PDA and MSNs-DOX@PDA-PEG by MTT assay after treatments for 12, 24 and 48 h in
MCF7 and MDA-MB-231 cells, respectively. Data were expressed as mean SD (*p< 0.05, **p< 0.01). (E) MTT assay of normal breast cell line
MCF10A, similar treatment as C and D. (F) BrdU incorporation assay by confocal microscopy (green: BrdU; blue: DAPI, scale bar ¼10 mm). (G)
Clone formation evaluation of MSNs@PDA-PEG, free DOX, MSNs-DOX@PDA and MSNs-DOX@PDA-PEG.
39644 |RSC Adv.,2017,7, 3964139650 This journal is © The Royal Society of Chemistry 2017
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of MSNs into solution. However, compared to the rapid release
of MSNs-DOX at pH 7.4, MSNs-DOX@PDA-PEG exhibited
a sustained DOX release rate at pH 7.4, suggesting that PDA-
PEG coating eectively protects DOX leakage from the MSNs
(cf. Fig. 2B). In particular, MSNs-DOX@PDA-PEG exhibited
a signicantly more rapid release rate at pH 5.0 compared to the
slower release rate at pH 7.4 (cf. Fig. 2B), a nding that could be
attributed to the pH sensitivity of PDA under acidic
Eective internalization of MSNs-DOX@PDA-PEG by cells
To determine the specic recognition and uptake capacity of
MSNs-DOX@PDA-PEG towards target cells, we carried out
Fig. 5 (A) MCF7 cells were treated with PBS, MSNs@PDA-PEG, free DOX, MSNs-DOX@PDA and MSNs-DOX@PDA-PEG for 12 h and autophagic
vehicles were observed. The cells were imaged under a confocal microscope (blue: DAPI, red: DOX, green: LC3, scale bar ¼10 mm). (B) MCF7
cells were treated similarly to (A) and Western blotting was performed with LC3, beclin 1, p62 and b-actin antibodies. (C) MCF7 cells were treated
similarly to (A) and Western blotting was performed with the indicated antibodies.
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confocal microscopy analysis to compare the cellular uptake
eciencies of free DOX and MSNs-DOX@PDA-PEG (Fig. 3A and
B). The results suggested that cellular uptake of MSNs-
DOX@PDA-PEG in MCF7 cells was signicantly higher than
that of free DOX. Furthermore, cellular uptake of MSNs-
DOX@PDA-PEG in MCF7 cells was remarkably higher than in
MCF10A cells. Flow cytometry analysis also conrmed the
enhanced cellular uptake of MSNs-DOX@PDA-PEG in MCF7
cells (Fig. 3C). Most likely, the increase of cellular uptake was
caused by PDA and PEG. Previous studies have reported similar
results in terms of PDA and PEG being able to increase the
cellular uptake of nanoparticles.
Inhibition of cell growth and proliferation by MSNs-
MCF7 and MDA-MB-231 cells (2.6 10
) were used to study the
in vitro cytotoxicity of MSNs-DOX@PDA-PEG. Fig. 4A and B
show the in vitro cell viability of the drug formulated in MSNs-
DOX@PDA-PEG and DOX at equivalent concentrations of 1, 5,
10, 25 and 35 mgmL
, respectively. The percentage of viable
cells was quantitatively assessed by an MTT method. MSNs or
MSNs@PDA-PEG did not exhibit a signicant cytotoxicity
against MCF7 and MDA-MB-231 cells in vitro. As reported
previously, extremely high concentrations of MSNs (about
25 mg mL
) at some sizes exhibit cytotoxicity.
the required maximum concentration of MSNs herein was
500 mgmL
, a concentration at which nearly no cytotoxicity
could be observed. Similarly to our result, PDA and PEG coating
was found to be nontoxic in various cell models and in various
in vivo studies.
MCF7 and MDA-MB-231 cells (2.6 10
) treated with
10 mgmL
MSNs-DOX@PDA-PEG for 12, 24 and 48 h, respectively. As
shown in Fig. 4C and D, MSNs@PDA-PEG exhibited no signi-
cant eect on the cell viability compared with the PBS control,
providing further evidence that MSNs@PDA-PEG represents
a safe and biocompatible nanocarrier. Both free DOX and
MSNs-DOX@PDA exhibited a signicant cell growth inhibition
while the MSNs-DOX@PDA-PEG demonstrated a stronger
inhibition ability to MCF7 and MDA-MB-231 compared to free
DOX and MSNs-DOX@PDA. However, for the normal breast cell
line MCF10A, both free DOX and MSNs-DOX@PDA exhibited
almost no cell growth inhibition as shown in Fig. 4E.
5-Fluorouridine (BrdU), a thymidine analogue, has been
crucial in the identication of DNA synthesis and the assess-
ment of cell proliferation. In the present research, a BrdU assay
Fig. 6 (A) Tumor growth curves of MCF7 xenografts treated with saline, free DOX, MSNs-DOX@PDA and MSNs-DOX@PDA-PEG, respectively. (B)
Xenograft tumors were removed and (C) weighted. Values are provided as mean standard error (*p< 0.05, **p< 0.01). (D) Representative H&E
staining of xenograft tumors.
39646 |RSC Adv.,2017,7, 3964139650 This journal is © The Royal Society of Chemistry 2017
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was performed. The MCF7 cells (6 10
) were treated with
10 mgmL
MSNs-DOX@PDA-PEG for 6 h and the BrdU incorporation was
detected by confocal microscopy. As shown in Fig. 4F, MSNs-
DOX@PDA-PEG exhibited the best inhibition eect on BrdU
A colony formation assay was also performed as described
MCF7 cells (1 10
) were treated with 10 mgmL
DOX@PDA-PEG for 7 days and the obtained colonies were
stained with 0.1% crystal violet. As shown in Fig. 4G, similar to
the MTT assay, MSNs-DOX@PDA-PEG exhibited a stronger
inhibition eect on the colony formation of MCF7 cells
compared to other treatments.
Induction of pro-death autophagy through suppression of
AKT-mTOR-p70S6K pathway by MSNs-DOX@PDA-PEG
Previously conducted research studies have shown that DOX can
induce pro-death autophagy.
Autophagy primarily represents
a degradation pathway that clears malfunctioning cellular
components, including intracellular pathogens, in response to
various types of stress. LC3 proteins play a critical role in auto-
phagy. Beclin 1 is considered to be related to the initiation and
progression of autophagy, albeit the underlying mechanism
remains unknown. The autophagy receptor and substrate
SQSTM1/p62 inhibits the E3 ligase ubiquitination of histone in
response to DNA double-strand breaks. Dysregulation of this
process leads to a reduced ability to repair DNA. Some studies
have shown evidence for the accumulation of beclin 1 and LC3B-
II, but degradation of p62. Meanwhile, the percentage of cells
with characteristic LC3B-GFP puncta structure, a characteristic
marker of autophagy, was increased following some autophagy
induced drug treatments.
In the present study, we investigated
the eects of MSNs@PDA-PEG, free DOX, MSNs-DOX@PDA and
MSNs-DOX@PDA-PEG on autophagy in MCF7 cells. As shown in
Fig. 5A, the number of autophagic vesicles (referred to LC3 dotted
green uorescence) was signicantly higher in MSNs-DOX@PDA-
PEG-treated cells compared to the other groups. Consistently,
MSNs-DOX@PDA-PEG treatment induced an increase in LC3-II
and p62 levels, however, a decrease in beclin 1 level in MCF7
cells was also observed (cf. Fig. 5B).
The AKT/mammalian target of rapamycin (mTOR)/p70 ribo-
somal protein S6 kinase (p70S6K) signaling pathway is known to
regulate autophagy.
To investigate whether MSNs-DOX@PDA-
PEG-induced autophagy is involved in the AKT-mTOR-p70S6K
signaling pathway, the phosphorylation levels of the associated
proteins were studied by Western blotting. As shown in Fig. 5C,
all of the treatments with free DOX, MSNs-DOX@PDA and MSNs-
DOX@PDA-PEG signicantly inhibited the phosphorylation
levels of AKT, mTOR, and p70S6K, however, MSNs-DOX@PDA-
PEG exhibited the best inhibition eect.
Signicant inhibition of the MCF7 subcutaneous xenogra
tumor growth by MSNs-DOX@PDA-PEG
The anti-tumor ecacy of MSNs-DOX@PDA-PEG was further
investigated in nude mice bearing subcutaneous MCF7 tumors.
The administration of free DOX, MSNs-DOX@PDA and MSNs-
DOX@PDA-PEG resulted in signicant growth suppression of
MCF7 xenogras compared to the PBS control group. As shown
in Fig. 6A, tumor growth in the treatment groups was
Fig. 7 (A) Body weight changes of mice treated with saline, free DOX, MSNs-DOX@PDA and MSNs-DOX@PDA-PEG. Data is expressed as mean
value standard error. (B) Representative H&E staining of heart, liver, spleen, lung, kidney.
This journal is © The Royal Society of Chemistry 2017 RSC Adv.,2017,7, 3964139650 | 39647
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signicantly slower than that in the PBS-control group. MSNs-
DOX@PDA-PEG demonstrated the best inhibition ability on
the xenogragrowth. At the end of the experiment, the average
tumor weight in the treatment groups was signicantly lower
than that in the PBS-control group and the MSNs-DOX@PDA-
PEG group featured the lowest tumor weight (cf. Fig. 6B and
C). Furthermore, an immunohistochemical study showed that
the tumor tissues from the treatment of MSNs-DOX@PDA-PEG
exhibited the fewest tumor cells and the highest level of tumor
necrosis compared to the other treatments (cf. Fig. 6D), indi-
cating a higher anti-tumor activity of MSNs-DOX@PDA-PEG.
The latter nding is presumably due to the EPR eect and the
controlled release at tumor sites.
The systematic toxicity of MSNs-DOX@PDA-PEG in vivo was
evaluated by body weight monitoring and H&E tissue section
staining of major organs including heart, liver, spleen, lung,
and kidney. No statistically signicant dierences in body
weight could be observed between the MSNs-DOX@PDA-PEG-
treated group and other groups (p> 0.05, data not shown) (cf.
Fig. 7A) and no noticeable histopathological abnormalities (cf.
Fig. 7B) could be observed in MSNs-DOX@PDA-PEG groups
suggesting that MSNs-DOX@PDA-PEG featured a good
biocompatibility and a low general toxicity in vivo.
In summary, a pH-sensitive drug delivery system involving
mesoporous silica nanoparticles coated with PDA and PEG was
successfully designed for the controlled release of cationic
amphiphilic drug DOX. Furthermore, MSNs-DOX@PDA-PEG
exhibited a good anti-cancer ecacy through the induction of
pro-death autophagy. The obtained results demonstrate that
the DOX-loaded MSNs-DOX@PDA-PEG featured competitive
advantages, including an excellent pH-sensitivity, suitable
cellular uptake and therapeutic ecacy with low side eects (cf.
Fig. 8).
Materials and methods
3-Mercaptopropyltrimethoxysilane (MPTMS, 95%), cetyl-
trimethyl ammonium bromide (CTAB), tetraethylorthosilicate
(TEOS), amino-terminated poly(ethylene glycol) (H
¼2000), hydrochloride dopamine and doxorubicin (DOX)
were purchased from J&K Scientic Ltd (Beijing, China).
Ammonium uoride (NH
F) was obtained from Aladdin
Industrial Co., Ltd. (Shanghai, China). Acetonitrile was
purchased from EM Science (HPLC grade, Mallinckrodt Baker,
USA). Dulbecco's modied eagle medium (DMEM), trypsin
EDTA solution (0.25%), fetal bovine serum (FBS) and penicillin-
streptomycin were obtained from GIBCO, Invitrogen Co.
(Carlsbad, NM, USA). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl
tetrazolium bromide (MTT) and bovine serum albumin (BSA)
were purchased from Amresco (Solon, OH, USA). 5-Fluorour-
idine (BrdU) was obtained from Sigma-Aldrich (St. Louis, MO,
USA). 6-Diamidino-2-phenylindole (DAPI) was obtained from
Biyuntian Co., Ltd (Nanjing, China). BrdU mouse monoclonal
antibodies were purchased from Abcam (Cambridge, MA, USA).
LC3 antibody (rabbit source) was purchased from Cell Signaling
Technology (Beverly, MA, USA). P62 antibody was purchased
from Abmart Inc. (Shanghai, China). Beclin 1 was purchased
from Cell Signaling Technology (Beverly, MA, USA) AKT, p-AKT,
mTOR, p-mTOR, p70s6k, p-p70s6k antibodies were purchased
from Santa Cruz (Santa Cruz, CA, USA). Human breast carci-
noma cell line MCF7, MDA-MB-231 and the normal breast cell
line MCF10A were purchased from American Type Culture
Collection (ATCC). Water used throughout the studies was ob-
tained from an ultrapure MilliQ water purication system
(resistance > 18 MUcm). All other chemicals of the highest
available quality were commercially obtained and used as
Synthesis of MSNs
MSNs were synthesized according to our previously reported
procedure with slight modication.
Briey, 1.82 g CTAB
(5 mM) and 3 g NH
F (81 mM) were dissolved in 500 mL of water
and heated to 80 C in a 1000 mL ask. Under vigorous stirring,
9 mL (8.41 g) TEOS was added dropwise to the mixture and the
temperature was then kept at 80 C for 6 h. The solid product
was centrifuged (12 000 rpm, 10 min), washed with water and
ethanol three times and dried at 40 Cin vacuo. To remove the
surfactant template (CTAB), the product was dispersed in 400
mL of ethanol containing 8 mL of hydrochloric acid (37%) and
reuxed at 80 C for 24 h. This procedure was repeated twice to
ensure that the surfactant was completely removed. The ob-
tained MSNs were centrifuged and washed with deionized
Preparation of MSNs-DOX@PDA-PEG
For DOX loading, 50 mg MSNs were added to a water solution
containing doxorubicin hydrochloride (2.5 mL, 10 mg mL
and the mixture was stirred for 24 h. The solution was centri-
fuged and washed with water to move the remaining DOX from
Fig. 8 Schematic illustration of the pH-sensitive release of DOX from
MSNs-DOX@PDA-PEG triggering pro-death cell autophagy.
39648 |RSC Adv.,2017,7, 3964139650 This journal is © The Royal Society of Chemistry 2017
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the surface of MSNs. DOX-loaded MSNs (MSNs-DOX) were dried
at 40 Cin vacuo. Polydopamine-coated NPs (MSNs-DOX@PDA)
were synthesized by incubating 50 mg of MSNs-DOX in
0.5 mg mL
dopamine hydrochloride in Tris buer (10 mM,
pH 8.5) for 6 h at room temperature with shaking. Then, MSNs-
DOX@PDA was centrifuged (12 000 rpm, 10 min) and washed
with water to remove any unpolymerized dopamine. The
mixture was then added to 2.5 mg NH
-PEG and the resulting
material was stirred for 3 h in the dark at room temperature.
PEG was employed to coat MSNs in order to ensure high
physiological stability.
Finally, PEG and PDA-coated MSNs-
DOX (MSNs-DOX@PDA-PEG) were centrifuged, washed three
times with water and dried at 40 Cin vacuo.
The sample was dropped onto a copper grid coated with
a carbon membrane and allowed to dry. Then, the surface
morphology of MSNs-DOX@PDA-PEG was observed by trans-
mission electron microscopy (TEM, Tecnai G2 20, FEI
Company, USA). Drug release from MSNs-DOX@PDA-PEG was
determined as described previously.
Cell uptake of MSNs-DOX@PDA-PEG
MCF7 cells were cultured in DMEM supplemented with 10% (v/v)
FBS and antibiotics (100 U mL
penicillin and 100 mgmL
streptomycin) in a humidied 5% CO
atmosphere at 37 C.
MCF7 cells were incubated with free DOX and MSNs-DOX@PDA-
PEG (equal quantity of DOX) at 37 C for 0.5 h, washed with cold
PBS three times, and then xed by 4% paraformaldehyde for
20 min. Then, the cells were washed with PBS, stained with 4,6-
diamidino-2-phenylindole (DAPI) for 15 min and observed by
confocal laser scanning microscopy (CLSM, Olympus Fluoview
FV-1000, Japan) with imaging soware. The images of the cells
were determined with dierential interference contrast channel,
blue channel (DAPI) excitation at 358 nm and red channel (DOX)
excitation at 543 nm.
Immunouorescence observations
MCF7 cells seeded on coverslips were treated with MSNs@PDA-
respectively. Cells were xed with 4% formaldehyde in PBS for
15 min and then permeabilized in PBS containing 0.1% Triton
X100 for another 7 min. The cells were blocked with 3% BSA for
2 h at RT and probed with an appropriate primary antibody
overnight at 4 C. The coverslips were then incubated with
rhodamine- and uorescein-conjugated secondary antibodies
for 2 h at RT. Aer staining with 0.5 mgmL
of DAPI for 10 min,
the cells were observed and imaged using an Olympus FV1000
confocal microscope.
MTT cell proliferation assay
Briey, 1 10
MCF7 cells per well seeded in triplicate into a 96-
well plate were treated with certain concentrations of free DOX,
MSNs-DOX@PDA and MSNs-DOX@PDA-PEG. At the appro-
priate time-points, 20 mL MTT (5 mg mL
) was added for 4 h at
37 C and all liquid was carefully removed. Optical density (OD)
values were measured with a spectrophotometer at 490 nm
following continuous agitation for 20 min with 130 mL DMSO.
Colony formation assay
MCF7 cells were seeded into a six-well plate (1 10
cells per
well) and cultured in DMEM with 10% bovine serum albumin.
MCF7 cells were treated with MSNs@PDA-PEG, free DOX,
MSNs-DOX@PDA and MSNs-DOX@PDA-PEG, respectively.
Aer 7 days, the resulting colonies were stained with 0.01% of
crystal violet and images were captured.
BrdU cell proliferation assay
MCF7 cells seeded in 12-well plates were treated with
DOX@PDA-PEG for 6 h, respectively. Cells were incubated
with 200 mM 5-uorouridine for 30 min. The medium was
removed and the cells were xed with 4% formaldehyde in PBS
for 15 min and permeabilized in PBS containing 0.1% Triton
X100 for 7 min. The cells were probed with a BrdU antibody
aer blocking with 3% BSA and assessed for BrdU incorpora-
tion by confocal microscopy.
Western blotting
The cells were lysed with lysis buer and equal amounts of
proteins were separated by 10% SDS-PAGE and transferred onto
a PVDF membrane. The membrane was blocked with 5% non-
fat milk in Tris-buered saline containing Tween 20 for 2 h at
room temperature and incubated overnight at 4 C with specic
primary antibodies. Aer washing for a total of three times with
TBST, the membrane was incubated with appropriate HRP-
linked secondary antibodies for 2 h at room temperature and
then detected with ECL reagent.
Xenogratumor growth assay
This study was performed in strict accordance with the NIH
guidelines for the care and use of laboratory animals (NIH
Publication no. 85-23 Rev. 1985) and was approved by the
Institutional Animal Care and Use Committee of Tsinghua
University. 45 week old female nude mice were purchased from
the Medical Experimental Animal Centre of Guangdong Prov-
ince. All animal experiments were approved by the Institutional
Animal Care and Use Committee of Tsinghua University. The
mice were housed in a specic-pathogen-free environment
maintained at 25 1C with 55% relative humidity and food as
well as water were provided. The mice were randomly allocated
into 4 groups with 4 animals per group. MCF7 cells (5 10
150 mL PBS) in sub-conuent condition were subcutaneously
injected into the mice. Six days aer tumor inoculation, the
mice were administered a daily intraperitoneal injection of DOX
(0.5 mg kg
). Tumor volumes were measured every three
days with a caliper and calculated according to the formula: V¼
), where Land Wrepresent the length and width,
respectively. All mice were sacriced 2030 days aer tumor
inoculation and the tumors were excised and weighed.
Statistical analysis
Values are expressed as the mean standard deviation of three
independent experiments. Comparisons were performed using
This journal is © The Royal Society of Chemistry 2017 RSC Adv.,2017,7, 3964139650 | 39649
Paper RSC Advances
a two-tailed paired Student's t-test. Dierences with p< 0.05
were considered signicant.
Conicts of interest
The authors declare no competing nancial interest.
This research was supported by the National Natural Science
Foundation of China (No. 81670141), Guangdong Natural
Science Foundation (No. 2014A030313758) and Science, Tech-
nology & Innovation Commission of Shenzhen Municipality
(No. JCYJ20160422170206664).
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RSC Advances Paper
... Autophagy is being investigated as a potential beneficial focus despite its association with pathologic diseases like cancer [56]. Multiple studies have demonstrated that autophagy is a reaction of many cancer cells to various anticancer treatments and functions as a cellular death process. ...
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Clinical chemotherapy is hindered due to its poor therapeutic impact and severe adverse effects. To work within the challenges of poor circulation stability and unexpected drug leakage in blood circulation, we developed pH-responsive nanoplatforms based on silk sericin-coated zeolitic imidazolate framework-8 to deliver the chemotherapeutic cabazitaxel (designated ZIF-8@CTX@SS, ZCS). ZIF-8's improved stability and biocompatibility can be attributed to the shielding of the naturally occurring and non-toxic sericin protein. ZIF-8's coordinating action triggers the release of CTX drugs in a low pH environment, like that observed in the microenvironment of tumor cells. Newly fabricated nanoparticles showed improved anticancer potential in liver cancer cells (HepG2 and Bel7402). According to the fluorescence-based mechanism of anticancer activity, ZIF-8@CTX@SS enhanced reactive oxygen species (ROS) levels and caused DNA fragmentation, which resulted in apoptosis. The study's findings indicate that ZIF-8@CTX@SS is a potentially biocompatible nanomaterial for drug delivery systems for treating liver cancer applications. Taken together with all the advantages in this investigation, this silk sericin-based nanoframework represents a promising approach for developing stimuli-responsive by employing natural polymers to enhance the chemotherapy effects.
... For instance, the use of DOX-loaded mesoporous silica nanoparticle (MSN) in breast cancer treatment has shown an increased level of apoptosis, in comparison with DOX treatment alone in both in vitro and in vivo experiments. The intracellular mechanisms also confirmed the induction of the prodeath autophagy signaling pathway through inhibition of the AKT-mTOR-p70S6K signaling pathway (130). Another study has shown the cytotoxic effects of silica-based NPs (SiNPs) in breast cancer cell lines through the mitochondrial apoptotic pathway. ...
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Autophagy regenerates cellular nutrients, recycles metabolites, and maintains hemostasis through multistep signaling pathways, in conjunction with lysosomal degradation mechanisms. In tumor cells, autophagy has been shown to play a dual role as both tumor suppressor and tumor promoter, leading to the discovery of new therapeutic strategies for cancer. Therefore, regulation of autophagy is essential during cancer progression. In this regard, the use of nanoparticles (NPs) is a promising technique in the clinic to modulate autophagy pathways. Here, we summarized the importance of breast cancer worldwide, and we discussed its classification, current treatment strategies, and the strengths and weaknesses of available treatments. We have also described the application of NPs and nanocarriers (NCs) in breast cancer treatment and their capability to modulate autophagy. Then the advantages and disadvantaged of NPs in cancer therapy along with future applications will be disscussed. The purpose of this review is to provide up-to-date information on NPs used in breast cancer treatment and their impacts on autophagy pathways for researchers.
... To incorporate DOX in the hydrophobic interior and gold nanomaterials in the hydrophilic envelope for computed tomography imaging and regulated drug delivery, with an encapsulation effectiveness of 48.4 %, pHsensitive micelles were produced using a redox biodegradable polymer during research conducted by Xiong and colleagues [88]. Similar effectiveness has been seen in breast cancer treatment with polydopamine (PDA) and polyethylene glycol (PEG)-coated pH-sensitive mesoporous silica nanomaterials and PVP-Ag-TiO 2 in terms of DOX encapsulation [89]. Hematite (α-Fe 2 O 3 ) nanomaterials influence on DOX's loading and entrapment effectiveness was explored by Emami Gerami et al. [90].According to the authors, drug loading and encapsulation effectiveness were increased by the addition of hematite (α-Fe 2 O 3 ) nanomaterials into chitosan-PVP nanocarrier. ...
Cancer, as one of the most challenging diseases of the last century, has a significant number of patients and deaths every year. Various strategies have been explored for the treatment of cancer. Chemotherapy is one of the methods of treating cancer. Doxorubicin is one of the compounds used in chemotherapy to kill cancer cells. Due to their unique properties and low toxicity, metal oxide nanoparticles are effective in combination therapy and increase the effectiveness of anti-cancer compounds. The limited in vivo circulatory period, poor solubility, and inadequate penetration of doxorubicin (DOX) restrict its use in cancer treatment, notwithstanding its attractive characteristics. It is possible to circumvent some of the difficulties in cancer therapy by using green synthesized pH-responsive nanocomposite consisting of polyvinylpyrrolidone (PVP), titanium dioxide (TiO2) modified with agarose (Ag) macromolecules. TiO2 incorporation into the PVP-Ag nanocomposite resulted in limited increased loading and encapsulation efficiencies from 41 % to 47 % and 84 % to 88.5 %, respectively. DOX diffusion among normal cells is prevented by the PVP-Ag-TiO2 nanocarrier at pH = 7.4, though the acidic intracellular microenvironments activate the PVP-Ag-TiO2 nanocarrier at pH = 5.4. Characterization of the nanocarrier was performed using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrophotometry, field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), and zeta potential. The average particle size and the zeta potential of the particles showed values of 349.8 nm and +57 mV, respectively. In vitro release after 96 h showed a release rate of 92 % at pH 7.4 and a release rate of 96 % at pH 5.4. Meanwhile, the initial release after 24 h was 42 % for pH 7.4 and 76 % for pH 5.4. As shown by an MTT analysis on MCF-7 cells, the toxicity of DOX-loaded PVP-Ag-TiO2 nanocomposite was substantially greater than that of unbound DOX and PVP-Ag-TiO2. After integrating TiO2 nanomaterials into the PVP-Ag-DOX nanocarrier, flow cytometry data showed a greater stimulation of cell death. These data indicate that the DOX-loaded nanocomposite is a suitable alternative for drug delivery systems.
... Moreover, quinone moieties in polydopamine structure allow the easy immobilization of different biomacromolecules containing amino or thiol groups, such as peptides and protein and growth factors [271]. As a result, PDA had been extensively investigated to develop controlled-release formulations of anticancer drugs [161,276,277]. ...
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... The observations were replicated in the nude mice harboring subcutaneous MCF-7 tumors, with MSNPs-DOX-PDA-PEG exhibiting the maximum inhibition in terms of maximum tumor weight decrements. Furthermore, no significant distinctions in the body weight and histopathological abnormalities (heart, liver, spleen, kidney and lungs) for all the carrier configurations imply the biocompatibility of MSNP-DOX-PDA-PEG [169]. This study, therefore, optimized the pH-specific DOX release kinetics via PDA and PEG-MSNP functionalization, conferring high tolerability with enhanced tumor cell uptake. ...
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Breast cancer (BC) currently occupies the second rank in cancer-related global female deaths. Although consistent awareness and improved diagnosis have reduced mortality in recent years, late diagnosis and resistant response still limit the therapeutic efficacy of chemotherapeutic drugs (CDs), leading to relapse with consequent invasion and metastasis. Treatment with CDs is indeed well-versed but it is badly curtailed with accompanying side effects and inadequacies of site-specific drug delivery. As a result, drug carriers ensuring stealth delivery and sustained drug release with improved pharmacokinetics and biodistribution are urgently needed. Core–shell mesoporous silica nanoparticles (MSNPs) have recently been a cornerstone in this context, attributed to their high surface area, low density, robust functionalization, high drug loading capacity, size–shape-controlled functioning, and homogeneous shell architecture, enabling stealth drug delivery. Recent interest in using MSNPs as drug delivery vehicles has been due to their functionalization and size–shape-driven versatilities. With such insights, this article focuses on the preparation methods and drug delivery mechanisms of MSNPs, before discussing their emerging utility in BC treatment. The information compiled herein could consolidate the database for using inorganic nanoparticles (NPs) as BC drug delivery vehicles in terms of design, application and resolving post-therapy complications.
... No obvious difference was observed between different shape groups. Due to the physical barriers formed by RBCM coating, DOX release was slowed down substantially [51]. Moreover, DOX release from FRMSN-D was slower than from both FRMSN-S and FRMSN-R. ...
How to enhance active targeting efficiency remains a challenge. Multivalent interactions play a crucial role in improving the binding ability between ligands and receptors. It is hypothesized that nanoparticles bearing a flat conformation attain simultaneous formation of multiple ligand-receptor bindings, which could be vividly met-aphorized by the "Hook&Loop" rationale. In this study, spherical, rod-shaped and disk-shaped folic acid-modified red blood cell membrane-coated biomimetic mesoporous silica nanoparticles (FRMSNs) were prepared to verify the shape-based multivalent interactions. The fundamental concepts of multivalent interactions have been proved by a series of both in vitro and in vivo evaluations. Physical characterization confirmed the morphology, shape and surface features of FRMSNs. Strengthened binding and internalization of disk-shaped FRMSNs by K562 cells stresses the merits of multivalent interactions. Whereas Bio-TEM visually demonstrates the proposed "plane" contact of disk-shaped particles with cells, quantification further confirmed strengthened "plane" binding affinity with folate binding proteins owing to multivalent interactions. In K562 xenograft mice, doxorubicin-loaded disk-shaped FRMSNs effectively slowed down chronic myeloid leukemia progression. It is concluded that disks favor multivalent interactions which leads to enhanced active targeting efficiency.
Efficient and highly controllable antibacterial effects, as well as good biocompatibility, are required for antibacterial materials to overcome multi-drug resistance in bacteria. Herein, mesoporous silica nanomaterials (MSNs) carriers with a particle mean size of 60 nm and pore size of 7.9 nm were prepared, which was followed by loading with D-cysteine (D-Cys) and modified with Polyethyleneimine (PEI) molecules on the outer surface (named as D@MSNs-P). The prepared D@MSNs-P showed a good pH response in the range of 5-7, and the rate of antibacterial agent D-Cys released from nanocarriers was much faster at lower pH (pH 5) than that at higher pH (pH 6-7), which favors the rapid control of the pathogenic bacteria. In a working pH (pH 5), D@MSNs-P exhibited broad-spectrum antibacterial activities against Escherichia coli, Staphylococcus aureus, Salmonella enteritidis, and Listeria monocytogenes with the highest antibacterial efficiency of 99.9%, 99.8%, 98.1%, and 96.2%, respectively, which is much higher than that of pure D-Cys, pure MSNs, D@MSNs, and PEI group. The outstanding antibacterial activity of D@MSNs-P was attributed to the synergistic effect of the unique structure of MSNs and chiral D-Cys molecules. In addition, the prepared D@MSNs-P has no cytotoxicity to HepG2 cells (Human hepatoma cells) at the concentration of 0.4-12.8 mg/mL and even can promote cell proliferation at high concentrations. Our results open a new door for designing the most promising nanomaterials for pH response release and controllable antimicrobial.
In this study, we report doxorubicin preparation with bioactive glass‐ceramic as a novel hybrid nanoparticle formulation. Synthesis was carried out through a bio‐inspired route where different precursors of bioactive glass are added to a Tris(hydroxymethyl)aminomethane buffer adjusted to slightly alkaline pH containing doxorubicin. With increasing concentration of doxorubicin, loading increased in quantity with comparatively higher drug release in acidic pH than neutral pH. Without synthetic surfactant or high temperature calcination, bioactive glass‐ceramic nanoparticles demonstrated significantly superior cytotoxic behavior towards osteosarcoma cell line when compared to equivalent free drug or its action towards non‐cancerous cell line. The particles exhibited hydroxyapatite deposition when immersed in simulated body fluid for 7 days. The bio‐inspired route for synthesis of doxorubicin‐bioactive glass‐ceramic hybrid nanoparticles is an efficient cost ‐effective synthesis mechanismwhich is environmentally friendly without hampering the stability or activity of the drug. We report one‐pot synthesis of doxorubicin‐bioactive glass ceramic nanoparticles (DOX‐BG) through the bio‐inspired route.In this study, doxorubicin servesas a template for facilitating formation of bioactive glass in presence of Tris(hydroxymethyl)aminomethane buffer (pH 8.5) and is also the chosen cargo for delivery. The obtained DOX‐BG nanoparticles are bioactive in nature and exhibit effective anti‐cancer activity against bone cancer cell line.
Nanoscale metal-organic frameworks (nMOFs) based nano drug delivery systems show great potential in biomedical field. In this work, a drug delivery system combined with chemotherapy and phototherapy (DOX/ICG@UiO-66-TK-PEG-F3 or simplified...
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Statement of significance: Proactive screening of high risk elderly patients now enables early detection of abdominal aortic aneurysms (AAAs). There are no established drug-based therapeutic alternatives to surgery for AAAs, which is unsuitable for many elderly patients, and none which can achieve restore disrupted and lost elastic matrix in the AAA wall, which is essential to achieve growth arrest or regression. We have developed a first generation design of polymer nanoparticles (NPs) for AAA tissue localized delivery of doxycycline, a modified tetracycline drug at low micromolar doses at which it provides both pro-elastogenic and anti-proteolytic benefits that can augment elastic matrix regenerative repair. The nanocarriers themselves are also uniquely chemically functionalized on their surface to also provide them pro-elastin-regenerative & anti-matrix degradative properties. To provide an active driving force for efficient uptake of intra-lumenally infused NPs to the AAA wall, in this work, we have rendered our polymer NPs mobile in an applied magnetic field via co-incorporation of super-paramagnetic iron oxide NPs. We demonstrate that such modifications significantly improve wall uptake of the NPs with no significant changes to their physical properties and regenerative benefits. Such NPs can potentially stimulate structural repair in the AAA wall following one time infusion to delay or prevent AAA growth to rupture. The therapy can provide a non-surgical treatment option for high risk AAA patients.
Full-text available
PICT-1 was originally identified as a tumor suppressor. Here, we found that PICT-1 overexpression triggered pro-death autophagy without nucleolar disruption or p53 accumulation in U251 and MCF7 cells. Truncated PICT-1 fragments 181-346 and 1-346, which partly or totally lack nucleolar localization, showed weaker autophagy-inducing effects than full-length PICT-1 and a well-defined nucleolar mutant (181-479). Furthermore, PICT-1 partly localizes to the nucleolar fibrillar center (FC) and directly binds to ribosomal DNA (rDNA) gene loci, where it interacts with upstream binding factor (UBF). Overexpression of PICT-1 or the 181-479 mutant, but not the 1-346 or 181-346 mutants, markedly inhibited the phosphorylation of UBF and the recruitment of rRNA polymerase I (Pol I) to the rDNA promoter in response to serum stimulation, thereby suppressing rRNA transcription, suggesting that rRNA transcription inhibition might be an important contributor to PICT-1-induced autophagy. This is supported by the finding that CX-5461, a specific Pol I inhibitor, also induced autophagy. In addition, both CX-5461 and PICT-1, but not the 1-346 or 181-346 mutants, significantly suppressed the activation of the Akt/mTOR/p70S6K signaling pathway. Our data show that PICT-1 triggers pro-death autophagy through inhibition of rRNA transcription and the inactivation of AKT/mTOR/p70S6K pathway, independent of nucleolar disruption and p53 activation.
Full-text available
The blood-brain barrier (BBB) is the major clinical obstacle in the chemotherapeutic management of brain glioma. Here we synthesized a pH-sensitive dual-targeting doxorubicin (DOX) carrier to compromise tumor endothelial cells, enhance BBB transportation, and improve drug accumulation in glioma cells. The drug delivery system was constructed with polydopamine (PDA)-coated mesoporous silica nanoparticles (NPs, MSNs) and the PDA coating was functionalized with Asn-Gly-Arg (NGR), a ligand with specific affinity for cluster of differentiation 13 (CD13). MSN-DOX-PDA-NGR showed a higher intracellular accumulation in primary brain capillary endothelial cells (BCECs) and C6 cells and greater BBB permeability than the non-targeting NPs (MSN-DOX-PDA) did in vitro. Ex vivo and in vivo tests showed that MSN-DOX-PDA-NGR had a higher accumulation in intracranial tumorous tissue than the undecorated NPs did. Furthermore, the antiangiogenesis and antitumor efficacy of MSN-DOX-PDA-NGR were stronger than that of MSN-DOX-PDA. Therefore, these results indicate that the dual-targeting vehicles are potentially useful in brain glioma therapy.
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In this study, we reported a simple polydopamine (pD)-based surface modification method to prepare novel nanoparticle-aptamer bioconjugates (Apt-pD-DTX/NPs) for in vivo tumor targeting and enhanced therapeutic effects of breast cancer. With simple preparation procedures, the new functionalized Apt-pD-DTX/NPs could maximumly increase the local effective drug concentration on tumor sites, achieving enhanced treatment effectiveness and minimizing side effects. The dopamine polymerization and aptamer conjugation barely changed the characters of NPs. Both in vitro cell experiments (i.e. endocytosis of fluorescent NPs, in vitro cellular targeting and cytotoxicity assays) and in vivo animal studies (i.e. in vivo imaging, biodistribution and antitumor effects of NPs) demonstrated that the Apt-pD-DTX/NPs could achieve significantly high targeting efficiency and enhanced therapeutic effects compared with clinical Taxotere® and NPs without functional modification. Above all, the Apt-pD-DTX/NPs showed great potential as a promising nanoformulation for in vivo breast cancer therapy and the construction of pD-modified NP-aptamer bioconjugates could be of great value in medical use.
Colorectal cancer (CRC) is one of the most common malignancies in the United States. Every 3 years, the American Cancer Society provides an update of CRC incidence, survival, and mortality rates and trends. Incidence data through 2013 were provided by the Surveillance, Epidemiology, and End Results program, the National Program of Cancer Registries, and the North American Association of Central Cancer Registries. Mortality data through 2014 were provided by the National Center for Health Statistics. CRC incidence rates are highest in Alaska Natives and blacks and lowest in Asian/Pacific Islanders, and they are 30% to 40% higher in men than in women. Recent temporal patterns are generally similar by race and sex, but differ by age. Between 2000 and 2013, incidence rates in adults aged ≥50 years declined by 32%, with the drop largest for distal tumors in people aged ≥65 years (incidence rate ratio [IRR], 0.50; 95% confidence interval [95% CI], 0.48-0.52) and smallest for rectal tumors in ages 50 to 64 years (male IRR, 0.91; 95% CI, 0.85-0.96; female IRR, 1.00; 95% CI, 0.93-1.08). Overall CRC incidence in individuals ages ≥50 years declined from 2009 to 2013 in every state except Arkansas, with the decrease exceeding 5% annually in 7 states; however, rectal tumor incidence in those ages 50 to 64 years was stable in most states. Among adults aged <50 years, CRC incidence rates increased by 22% from 2000 to 2013, driven solely by tumors in the distal colon (IRR, 1.24; 95% CI, 1.13-1.35) and rectum (IRR, 1.22; 95% CI, 1.13-1.31). Similar to incidence patterns, CRC death rates decreased by 34% in among individuals aged ≥50 years during 2000 through 2014, but increased by 13% in those aged <50 years. Progress against CRC can be accelerated by increasing initiation of screening at age 50 years (average risk) or earlier (eg, family history of CRC/advanced adenomas) and eliminating disparities in high-quality treatment. In addition, research is needed to elucidate causes for increasing CRC in young adults. CA Cancer J Clin 2017.
In this work, dextran, a polysaccharide with excellent biocompatibility, is applied as the "gatekeeper" to fabricate the pH-sensitive dextran/mesoporous silica nanoparticles (MSNs) based drug delivery systems for controlled intercellular drug release. Dextran encapsulating on the surface of MSNs is oxidized by NaIO4 to obtain three kinds of dextran dialdehydes (PADs), which are then coupled with MSNs via pH-sensitive hydrazone bond to fabricate three kinds of drug carriers. At pH 7.4, PADs block the pores to prevent premature release of anti-cancer drug doxorubicin hydrochloride (DOX). However, in the weakly acidic intercellular environment (pH ∼ 5.5) the hydrazone can be ruptured; and the drug can be released from the carriers. The drug loading capacity, entrapment efficiency and release rates of the drug carriers can be adjusted by the amount of NaIO4 applied in the oxidation reaction. And from which DOX@MSN-NH-N=C-PAD10 is chosen as the most satisfactory one for the further in vitro cytotoxicity studies and cellular uptake studies. The results demonstrate that DOX@MSN-NH-N=C-PAD10 with an excellent pH-sensitivity can enter HeLa cells to release DOX intracellular due to the weakly acidic pH intercellular and kill the cells. In our opinion, the ingenious pH-sensitive drug delivery systems have application potentials for cancer therapy.
Single-walled carbon nanotubes (SWNTs) are often the subject of investigation as an effective photothermal therapy (PTT) agent owing to unique strong optical absorption. Doxorubicin (Dox)-loaded SWNTs (SWNTs-Dox) can be used as an efficient therapeutic agent for combined near infrared (NIR) cancer photothermal and chemotherapy. However, SWNTs-Dox-mediated induction of cancer cell death was not fully investigated especially the reaction of Dox inside cancer cells by PTT. In this study, we examined how SWNTs-Dox promoted effective MDA-MB-231 cell death compared to Dox and PTT alone. We successfully synthesized Dox-loaded SWNTs (SWNTs-Dox). SWNTs-Dox exhibited a slow Dox release, which was accelerated by NIR irradiation. Furthermore, Dox released from SWNTs-Dox accumulated inside the cells at high concentration and effectively localized into the MDA-MB-231 cell nucleus. A combination of SWNTs-Dox and PPT promoted an effective MDA-MB-231 cell death by mitochondrial disruption and ROS generation. Thus, SWNTs-Dox can be utilized as an excellent anticancer agent for early breast cancer treatment.
Anticancer drug doxorubicin hydrochloride (DOX) loaded photothermal nanocomposite MnFe2O4@mSiO2 with magnetic targeting and T1/T2-weighted dual modes magnetic resonance imaging of MnFe2O4 core and NIR/pH-coupling sensitive mesoporous silica shell nanocarriers were designed and synthesized successfully. The anticancer drug DOX can be absorbed into mesoporous layer of MnFe2O4@mSiO2 nanocomposite, which shows obvious photothermal/chemo dual-modal synergistic therapies triggered by NIR/pH. Under 808 nm irradiation, MnFe2O4 can transform light into thermo, which can not only ablate tumor cells directly, but promote chemotherapy drugs releasing from mesoporous layer to kill tumor cells. The lower pH can also promote DOX releasing from mesoporous layer to enhance tumor inhibitory effect. It is confirmed that biocompatible DOX-MnFe2O4@mSiO2 nanocomposites can act as a potential multifunctional platform for effective magnetic targeting photothermal/chemo dual-modal synergistic therapies with enhanced anti-tumor efficacy and T1/T2-weighted dual modes magnetic resonance imaging (MRI) applications in vivo.
Molecule-targeted therapy has become the research focus for hepatocellular carcinoma (HCC). Persistent PI3K-AKT activation is often detected in HCC, representing a valuable oncotarget for treatment. Here, we tested the anti-HCC activity by a potent AKT inhibitor: AKT inhibitor 1/2 (AKTi-1/2). In both established (HepG2 and Huh-7) and primary human HCC cells, treatment with AKTi-1/2 inhibited cell survival and proliferation, but induced cell apoptosis. AKTi-1/2 blocked AKT-mTOR activation, yet simultaneously provoked cytoprotective autophagy in HCC cells. The latter was evidenced by ATG-5 and Beclin-1 upregulation, p62 downregulation as well as LC3B-GFP puncta formation. Autophagy inhibition, via pharmacological inhibitors (3-methyladenine, ammonium chloride, and bafilomycin A1) or Beclin-1 siRNA knockdown, significantly potentiated AKTi-1/2-induced HepG2 cell death and apoptosis. In nude mice, AKTi-1/2 intraperitoneal injection inhibited HepG2 tumor growth. Significantly, its anti-tumor activity in vivo was further sensitized when combined with Beclin-1 shRNA knockdown in HepG2 tumors. Together, these results demonstrate that autophagy activation serves as a main resistance factor of AKTi-1/2 in HCC cells. Autophagy prevention therefore sensitizes AKTi-1/2-induced anti-HCC activity in vitro and in vivo.
An appropriate co-delivery system for chemotherapeutic agents and nucleic acid drugs will provide a more efficacious approach for the treatment of cancer. Combining gene therapy with chemotherapeutics in a single delivery system is more effective than individual delivery systems carrying either gene or drug. In this work, we developed folate (FA) receptor targeted magnetic-mesoporous silica nanoparticles for the co-delivery of VEGF shRNA and doxorubicin (DOX) (denoted as M-MSN(DOX)/PEI-FA/VEGF shRNA). Our data showed that M-MSN(DOX)/PEI-FA could strongly condense VEGF shRNA at weight ratios of 30:1, and possesses higher stability against DNase I digestion and sodium heparin. In vitro antitumor activity assays revealed that HeLa cell growth was significantly inhibited. The intracellular accumulation of DOX by confocal microscopy and fluorescence spectrophotometry showed that M-MSN(DOX)/PEI-FA were more easily taken up than non-targeted M-MSN(DOX). Quantitative PCR and ELISA data revealed that M-MSN/PEI-FA/VEGF shRNA induced a significant decrease in VEGF expression as compared to cells treated with either the control or other complexes. The invasion and migration phenotypes of the HUVECS were significantly decrease after co-culture with MSN/PEI-FA/VEGF shRNA nanocomplexes-treated HeLa cells. The approach provides a potential strategy to treat cancer by a singular nanoparticle delivery system.