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ABSTRACT: We have previously demonstrated that pterostilbene, a compound in blueberries, exerts antiproliferative effects against pancreatic adenocarcinoma. However, little is known about the anti-inflammatory effects of pterostilbene in pancreatitis. Therefore, the aim of this study was to evaluate the effect of pterostilbene on inflammatory markers in an in vitro pancreatitis model. We hypothesized that pterostilbene would ameliorate the immediate inflammatory response in tumor necrosis factor alpha (TNF-α)-induced pancreatitis through downregulation of signal transducer and activator of transcription 3 (STAT3) and inhibition of TNF-α-induced secretion of lipase and proinflammatory cytokines interleukins (ILs) 1β and 6.
AR42J acinar cells were pretreated with TNF-α to induce pancreatitis followed by 25 and 50μM pterostilbene for 15 and 30min. Secretion of lipase was quantified using a lipase assay and used as a marker of TNF-α-induced pancreatitis. Detection of STAT3, IL-1β, and IL-6 was performed using enzyme-linked immunosorbent assay. Analysis of variance and Tukey post hoc analysis were used for statistical analysis.
TNF-α increased the secretion of lipase, IL-1β, and IL-6. Pterostilbene treatment inhibited TNF-α-induced secretion of lipase (P<0.01 and P<0.001), IL-1β (P<0.05), and IL-6 (P<0.05 and P<0.01). Inhibition of STAT3 by pterostilbene occurred with treatment doses of 25 and 50μM (P<0.001 and P<0.01).
The dietary compound pterostilbene exerts an anti-inflammatory effect in pancreatitis through downregulation of STAT3 and decreased the secretion of lipase, IL-1β, and IL-6. Pterostilbene's amelioration of pancreatitis in vitro makes it an advantageous anti-inflammatory agent. Further studies are necessary to determine pterostilbene's role as a protective or therapeutic agent in pancreatitis.
Journal of Surgical Research 08/2012; 178(1):28-32. · 2.25 Impact Factor
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ABSTRACT: BACKGROUND: The ability of a breast cancer cell to evade apoptosis has a key role in tumor progression and sensitivity to treatment. High levels of Bcl-2-associated X protein (Bax) in tumor cells have been found to promote apoptosis and sensitize cells to anti-cancer therapies. Bcl-2-associated X protein redistribution to the mitochondrial membrane results in the release of proapoptotic factors including cytochrome C, second-mitochondrial-derived activator of caspase/direct inhibitor of apoptosis-binding protein with low PI (Smac/DIABLO), and Ca(2+). We aimed to explore this pathway in cancerous breast cell lines treated with the naturally occurring antioxidant 3,5-dimethoxy-4-hydroxystilbene (pterostilbene). METHODS: We used whole cell lysates +/- Bax SiRNA from the cell lines MCF-7 and MDA-MB-231 in an enzyme-linked immunosorbent assay to quantify Bax, cytochrome C, Smac/DIABLO expression, and manganese superoxide dismutase (MnSOD) activity after treatment with pterostilbene. We quantified cell death using histone-related DNA complexes from cytosolic and mitochondrial fractions and used methylthiazol tetrazolium assay to analyze cell proliferation, in the presence of Bax-silencing or scrambled RNA. We measured changes in cytosolic calcium using the ratiometric calcium-sensitive dye fura-2-AM using an inverted ratiometric monochromator microscope. RESULTS: Treatment of MCF-7 and MDA-MB-231 (MDA) cells with pterostilbene caused concentration-dependent increases in intracellular Bax at all doses tested. RNA silencing of Bax resulted in reduced rates of apoptosis in both cells types and increased cell survival when treated with pterostilbene. We observed an increase in cytochrome C in MDA cells after treatment with pterostilbene. The MCF-7 cells showed a net increase in cytosolic cytochrome C, with a corresponding reduction in mitochondrial cytochrome C after treatment with 50 and 75 μmol/L pterostilbene. We observed this again in Smac/DIABLO expression in both cell types. In MCF-7 cells, pterostilbene treatment caused an increase in cytosolic but a decrease in mitochondrial Smac/DIABLO protein concentrations. Pterostilbene significantly increase MnSOD activity in MDA-MB-231 cells. Finally, pterostilbene resulted in significant increases in cytosolic calcium concentrations. CONCLUSIONS: The natural dietary compound pterostilbene has an anti-proliferative effect and induces apoptosis in breast cancer cells in vitro via Bax activation and overexpression, resulting in increased MnSOD, Smac/DIABLO, and cytochrome C activity and cytosolic Ca(2+) overload.
Journal of Surgical Research 04/2012; · 2.25 Impact Factor
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ABSTRACT: To investigate the inhibitory role of pterostilbene in pancreatic cancer, we conducted a genomic analysis of pterostilbene-treated pancreatic cancer cells. We also investigated the effect of pterostilbene upon the carcinogenic markers, manganese superoxide dismutase, cytochrome C, Smac/DIABLO, and STAT3 phosphorylation in vitro. The antiproliferative effects of pterostilbene were further evaluated in an in vivo model.
Pancreatic cancer cells were treated with pterostilbene and evaluated with DNA microarray analysis. Pterostilbene-treated cells were analyzed for cytochrome C, Smac/DIABLO, manganese superoxide dismutase (MnSOD)/antioxidant activity, and STAT3 phosphorylation using ELISA. Data were statistically analyzed using ANOVA. Pterostilbene was then administered to nude mice for 8 weeks, and tumor growth rates were recorded and statistically analyzed.
Microarray analysis of pterostilbene-treated cells revealed upregulation of pro-apoptosis genes. In vitro, pterostilbene treatment altered levels of phosphorylated STAT3, MnSOD/antioxidant activity, cytochrome C, and Smac/DIABLO. In nude mice, oral pterostilbene inhibited tumor growth rates.
Pterostilbene alters gene expression in pancreatic cancer and increases the antiproliferative markers cytochrome C, Smac/DIABLO, and MnSOD/antioxidant activity. It was also shown to inhibit phosphorylated STAT3, a marker of accelerated tumorigenesis, and decrease pancreatic tumor growth in vivo. Further studies are warranted to elucidate the effects of pterostilbene in humans.
Journal of Gastrointestinal Surgery 03/2012; 16(6):1136-43. · 2.83 Impact Factor
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ABSTRACT: Pterostilbene (trans-3,5-dimethoxy-4-hydroxystilbene) is an antioxidant that is primarily found in blueberries. Studies suggest that pterostilbene exhibits the hallmark characteristics of an effective anticancer agent based on its antineoplastic properties in several common malignancies. In vitro models have shown that pterostilbene inhibits cancer growth through alteration of the cell cycle, induction of apoptosis, and inhibition of metastasis. In vivo, pterostilbene inhibits tumorigenesis and metastasis with negligible toxicity. Pterostilbene has also been shown to be effective as an inducer of antioxidant capacity in multiple cancer cell lines that may facilitate its function as an anticarcinogenic compound. Additionally, preliminary studies show that pterostilbene exhibits much greater bioavailability compared with other stilbene compounds; however the exact pharmacologic mechanism of pterostilbene and its effects in humans are still under investigation. In this review, we present a comprehensive summary of the antineoplastic mechanisms of pterostilbene based on the results of preclinical studies and highlight recent advances in the study of this dietary compound.
Journal of Surgical Research 10/2011; 173(2):e53-61. · 2.25 Impact Factor
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ABSTRACT: The hormone leptin is implicated in breast carcinogenesis in obese women. One mechanism is through its activation of Janus kinase/signal transducer and activator of transcription (JAK/STAT3) and apoptosis dysregulation. We have shown that the antioxidant pterostilbene inhibits proliferation and induces apoptosis in breast cancer. Therefore, the goal of this study was to evaluate the effect of pterostilbene on cell proliferation and JAK/STAT3 signaling in leptin-stimulated breast cancer.
Breast cancer cells were treated with leptin alone or in combination with pterostilbene. Detection of cell proliferation and JAK/STAT3 signaling were performed using enzyme-linked immunosorbent assay protocols. Statistical analysis was performed with analysis of variance and Tukey post hoc analysis.
Pterostilbene suppresses constitutive as well as leptin-induced JAK/STAT3 activation. Pterostilbene treatment also inhibited leptin-induced cell proliferation.
Pterostilbene has an inhibitory effect on leptin-stimulated breast cancer in vitro through reduction of cell proliferation and JAK/STAT3 signaling, a critical regulatory component of tumorigenesis in obesity-related breast cancer.
American journal of surgery 09/2011; 202(5):541-4. · 2.36 Impact Factor
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ABSTRACT: Tamoxifen is widely used for the treatment of breast cancer. Pterostilbene, a bioavailable stilbenoid found in blueberries, has been found to inhibit breast cancer growth in vitro. It was hypothesized that combining pterostilbene with tamoxifen would produce additive effects on estrogen receptor-positive breast cancer cells.
Two estrogen receptor-positive breast cancer cell lines, MCF7 and ZR-751, were pretreated with graduated doses of pterostilbene for 24 hours, followed by 5 μmol/L tamoxifen. MTT proliferation assays and Cell Death Detection ELISA(PLUS) tests evaluated cell viability and apoptosis.
MCF7 cells showed inhibition (10 and 20 μmol/L, P < .001; 30 μmol/L, P < .05) at all time points when combined with tamoxifen. ZR-751 cells showed additive reductions in cell viability (P < .001). Cell Death Detection ELISA(PLUS) indicated increased apoptosis (P < .01).
Pterostilbene shows an additive inhibitory effect on breast cancer cells when combined with tamoxifen, most likely from augmented cancer cell apoptosis.
American journal of surgery 11/2010; 200(5):577-80. · 2.36 Impact Factor
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ABSTRACT: STAT1 and STAT3, members of the cytoplasmic family of signal transducers and activators of transcription factors (STAT), have been associated with numerous inflammatory pathologies, including inflammatory bowel disease, hepatitis, and acute lung injury. But little is known about their role in the pancreas. Peptide YY (PYY), an inhibitory gastrointestinal hormone, ameliorates pancreatitis in vivo and in vitro. In addition, we have shown that PYY attenuates transcription factors, such as nuclear transcription factor (NF)-kappaB and Smad3/4, which mediate inflammation. We hypothesized that tumor necrosis factor (TNF)-alpha would induce STAT1 and STAT3, and PYY would attenuate their transcription factor binding.
Rat pancreatic acinar cells were treated with recombinant TNF-alpha (200 ng/mL); PYY (3-36; 500 pM) was added 30 minutes post-TNF-alpha treatment. Cells were harvested at 2 hours, and nuclear protein and conditioned media were extracted. Levels of amylase secretion and cytokine production were measured using commercially available kits. STAT transcription factor binding was determined by protein/DNA array analysis and densitometry; results were verified again by electrophoretic mobility shift assay (EMSA) and ELISA-based assay.
Amylase production was considerably increased (p < 0.05) as early as 5 minutes after addition of exogenous TNF-alpha and remained elevated for 24 hours. PYY decreased amylase production to control levels. A notable increase (p < 0.05) in the production of cytokines interleukin (IL)-1beta, IL-4, IL-6, IL-10, and TNF-alpha was observed with TNF-alpha treatment; production was reduced with PYY. TNF-alpha substantially upregulated STAT1 and STAT3 (two-fold or greater); PYY downregulated their binding activity to control levels. Results from both the electrophoretic mobility shift assay- and the ELISA-based assays verified STAT1 and STAT3 responses to TNF-alpha and PYY.
In pancreatic acinar cells, TNF-alpha activated STAT1 and STAT3, known mediators of inflammatory cytokines. Interestingly, PYY attenuated their protein/DNA binding, which may have an impact on development of the disease. Additional investigation of STAT proteins and PYY could provide new therapeutic strategies for pancreatitis.
Journal of the American College of Surgeons 05/2006; 202(5):788-96. · 4.55 Impact Factor
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ABSTRACT: Acute pancreatitis (AP) is a disease characterized by inflammation. Nuclear factor (NF)-kappaB, Smad proteins, and the steroid hormone family peroxisome proliferator-activated receptors (PPARs) are involved in regulation of gene transcription during the disease process. Peptide YY (PYY), a gastrointestinal hormone, inhibits NF-kappaB translocation to acinar nuclei in tumor necrosis factor (TNF)-alpha-induced AP. We investigated TNF-alpha induction of Smad proteins, PPARalpha/gamma, and NF-kappaB by TNF-alpha, and hypothesized that PYY would attenuate this effect.
Rat acinar cells were treated with recombinant TNF-alpha (200 ng/mL). PYY (3 to 36) was added at 500 pM at 30 minutes after TNF-alpha treatment until cell harvest at 2 hours. Western blot analysis and intracellular staining of the p65 subunit of NF-kappaB were performed. NF-kappaB, Smad3/4, and PPARalpha/gamma binding activities were determined by protein/DNA array analysis and verified by electrophoretic-mobility shift assay and densitometry.
Cellular localization of NF-kappaB p65 showed nuclear staining within 2 hours, with controls stained in the cytoplasm. With PYY, p65 stained in the cytoplasm. Nuclear p65 was increased significantly (p < 0.05) by TNF-alpha at 2 hours and PYY reduced it. Array analysis revealed upregulation of NF-kappaB, PPARalpha/gamma, and Smad3/4 with TNF-alpha. TNF-alpha stimulated NF-kappaB activation sevenfold, and binding was enhanced (p < 0.05). PYY reduced NF-kappaB binding to control levels. PPAR binding increased 51% after TNF-alpha treatment and was reduced to 33% with PYY. Smad3/4 binding was increased (p < 0.05) above controls with TNF-alpha and PYY reduced it by 40%.
TNF-alpha increases early nuclear translocation of the p65 subunit of NF-kappaB in acinar cells. Exposure to TNF-alpha activates transcription factors NF-kappaB, Smad3/4, and PPARalpha/gamma. PYY reduces this activation. Treatment with PYY may have therapeutic potential in improving AP.
Journal of the American College of Surgeons 07/2004; 199(1):87-95. · 4.55 Impact Factor
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ABSTRACT: Keyhole limpet hemocyanin (KLH) is a recently described immune stimulant and hapten carrier derived from a circulating glycoprotein of the marine mollusk Megathura crenulata. It has been reported to be a potent form of intravesical immunotherapy for the treatment of transitional cell carcinoma of the bladder and has been used in a variety of genitourinary tumors. We hypothesized that KLH would be effective against other cancer cells in vitro.
Multiple cancer cell lines were tested, including estrogen-dependent breast (MCF-7), estrogen-independent breast (ZR75-1), pancreas (PANC-1, MIA-PaCa), and prostate (DU145). Serial twofold dilutions of KLH were prepared in sterile 96-well plates. Dose-response curves were performed beginning with a concentration of 100 microg of KLH/well and ending at a concentration of 0.8 ng/well. Cells were added at concentrations of 5 x 10(4) cells per well. Cell viability was evaluated at 24 and 72 h by MTT assay at an absorbance of 570 nm.
Significant (P < 0.05) cancer cell growth inhibition was observed in four of the five cell lines tested at both time treatment intervals. The breast cancer line ZR75-1 exhibited a mean growth inhibition of 43 +/- 1.1% (range 37 to 59%) at 72 h, whereas treated MCF-7 cells had an average of 39 +/- 9.1% growth inhibition (range 35 to 44%) at these same concentrations. Treated PANC-1 cells had a mean growth inhibition of 19 +/- 0.8% (range 4 to 46%) at 72 h. The DU145 prostate cancer cell line averaged a 6 +/- 1.3% growth inhibition (range -19 to 55%) over the concentrations tested.
The direct growth inhibition of multiple tumor cell-lines exhibited by KLH is significant and warrants further in vitro mechanistic studies and in vivo experiments. Investigation into the efficacy and mechanism of response could directly lead to more effective treatment regimens for patients suffering from these diseases.
Journal of Surgical Research 12/2002; 108(2):279-84. · 2.25 Impact Factor
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ABSTRACT: During the past two decades, there has been a remarkable increase in the availability and utility of tumor markers and tumor genetics in the diagnosis, and management of the various GI malignancies. Still, there is considerable variability among physicians in the use of followup studies following potentially curative resection of any of the GI cancers. Multiple surveillance strategies have been published at cost ranging from a few hundred to several thousand dollars per patient. Therefore, the literature on the currently available GI tumor markers, will be reviewed. Those tumor markers can be tested and detected basically in one of two clinical settings: (a) serum-based; in serum specimens, and (b) tissue-based; in endoscopic and surgical specimens.
The West Virginia medical journal 104(4):17-21.
