• International Journal of Oral Biology
• /
• 제44권2호
• /
• pp.43-49
• /
• 2019

Tannic acid (TA) is a water-soluble polyphenol compound found in various herbal plants. We investigated the chemopreventive effects of TA on FaDu hypopharyngeal squamous carcinoma cells. In an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, TA showed dose-dependent cytotoxicity with a half maximal inhibitory concentration (IC50) of 50 ?M. Cell cycle analysis and immunofluorescence imaging demonstrated that under low-dose ($25{\mu}M$) treatment, FaDu cells were arrested in G2/M phase, and as the dose of TA was increased, apoptosis was induced with the increase of cell population at sub-G1 phase. The expressions of various cyclins, including cyclin D1 and cyclin-dependent kinases (CDK-1 and CDK-2), were down-regulated at low doses of TA, whereas apoptotic effectors such as cleaved caspase 3, cleaved caspase 7, and poly (ADP-ribose) polymerase (PARP) were expressed in a dose-dependent manner in Western blotting. In addition, TA-induced apoptosis of FaDu cells might be mediated by the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase pathway, with the upregulation of p-AKT/p-PKB (phosphorylated protein kinase B) and p-ERK. Overall, our data support the hypothesis that TA is a potential candidate agent for the treatment of hypopharyngeal cancer.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권12호
• /
• pp.7473-7482
• /
• 2013

The G-protein coupled receptor 87 (GPR87) is a recently discovered orphan GPCR which means that the search of their endogenous ligands has been a novel challenge. GPR87 has been shown to be overexpressed in squamous cell carcinomas (SCCs) or adenocarcinomas in lungs and bladder. The 3D structure of GPR87 was here modeled using two templates (2VT4 and 2ZIY) by a threading method. Functional assignment of GPR87 by SVM revealed that along with transporter activity, various novel functions were predicted. The 3D structure was further validated by comparison with structural features of the templates through Verify-3D, ProSA and ERRAT for determining correct stereochemical parameters. The resulting model was evaluated by Ramachandran plot and good 3D structure compatibility was evidenced by DOPE score. Molecular dynamics simulation and solvation of protein were studied through explicit spherical boundaries with a harmonic restraint membrane water system. A DRY-motif (Asp-Arg-Tyr sequence) was found at the end of transmembrane helix3, where GPCR binds and thus activation of signals is transduced. In a search for better inhibitors of GPR87, in silico modification of some substrate ligands was carried out to form polar interactions with Arg115 and Lys296. Thus, this study provides early insights into the structure of a major drug target for SCCs.

• International Journal of Oral Biology
• /
• 제36권2호
• /
• pp.59-64
• /
• 2011

Anthocyanins are naturally occuring phytochemicals and the main components of the coloring of plants, flowers and fruits. They are known to elicit antioxidative, anti-inflammatory and cancer preventive activity. In this study, we investigated anthocyanins in black / yellow soybean seedcoats using different methods of detection - thin layer chromatography (TLC), capillary zone electrophoresis (CZE) and HPLC analysis. The anthocyanins in soybean seedcoats were extracted by five independent methods of extraction and the aglycons (anthocyanidins) of the corresponding anthocyanins were prepared by acid mediated hydrolysis. The anthocyanin / anthocyanidin in black soybean seedcoat showed characteristic TLC mobility, CZE electrophoretic retention and HPLC migration time while little of anthocyanins were detected from yellow soybean seedcoat. The extracted anthocyanins showed pH dependent retention time in CZE and spectral change in UV-Vis spectrum. HPLC analysis of the hydrolyzed extract of black soybean seedcoat identified the presence of four anthocyanidins. The major anthocyanin in black soybean seedcoat was cyanin (cyanidin-3-O-glucoside), with the relative order of anthocyanidin in cyanidin > delphinidin > petunidin > pelargonidin.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권5호
• /
• pp.2527-2533
• /
• 2016

Sensitising cancer cells and at the same time desensitizing normal cells is a double task in cancer management. Agents which can combat the debilitating side effects of cancer therapeutics and simultaneously synergize with anticancer agents in specifically targeting cancer cells are needed. Selenium, a proven anticarcinogen, gains due importance in terms of its efficacy to combat the side effects of cancer therapy. This study is a comparative analysis of the chemoprotective effects of selenium compounds, methyl selenol (generated from organic selenomethionine (5mmol/L ; METase 40U/L)) and sodium selenite (inorganic form)($30{\mu}M$) in peripheral blood human lymphocytes exposed to cisplatin and mitomycin. Biochemical alterations occurring in many cells during apoptosis include loss of plasma membrane phospholipid asymmetry, DNA fragmentation, and activation of caspase-3. The present study demonstrated that the selenium metabolite and selenite are efficient in protecting lymphocytes undergoing DNA damage and exerted their activity by reducing caspase 3 expression. Interestingly organic methylselenol (MeSe) was found to offer more protective effects compared to inorganic selenite (SeL), by reducing the induction of apoptosis by the cytotoxic agents. This suggests that MeSe and to a lesser extent selenite might have potential for assessment in clinical trials and could be considered as strong candidates in pharmacogenomics or in the nutriprotective arena.

• Biomolecules & Therapeutics
• /
• 제13권2호
• /
• pp.113-117
• /
• 2005

Organosulfur compounds have been shown to exert an anti-cancer activity. In an attempt to develop novel chemopreventive and anti-cancer agents for liver cancer, we synthesized allylthiopyridazine derivatives. We have previously shown that allylthiopyridazine derivatives exert inhibitory effects on proliferation, invasion and migration of SK-Hep-1 hepatocarcinoma cells in vitro. The in vivo anti-tumor effect of 3-methvl-6-allylthiopy-ridazine, named as K6, was also reported. In this study, we further investigated the preclinical anti-cancer efficacy of K6 for hepatocarcinoma using nude mice xenografted with Hep-G2 hepatocellular carcinoma cells. K6(20-100 mg/kg, orally administered everyday for 30 days) markedly decreased the tumor volume of Hep-G2 cell-transplanted nude mice as evidenced by ultrasonographic and plethysmogranhic analyses. The inhibitory effect on tumor volume was lower than that exerted by doxorubicin (2 mg/kg), intravenously injected) which was used as a positive control. This study shows that K6 efficiently suppresses xenograft tumor growth, revealing K6 as apotential anti-cancer agent for suppressing in vivo progression of liver cancer. Given that hepatocarcinoma is among the most prevalent and lethal malignancies and there is no effective treatment to date, our study may contribute to the potential drug development for liver cancer.

• Biomolecules & Therapeutics
• /
• 제24권4호
• /
• pp.380-386
• /
• 2016

Silymarin from milk thistle (Silybum marianum) has been reported to show an anti-cancer activity. In previous study, we reported that silymarin induces cyclin D1 proteasomal degradation through NF-${\kappa}B$-mediated threonine-286 phosphorylation. However, mechanism for the inhibition of Wnt signaling by silymarin still remains unanswered. Thus, we investigated whether silymarin affects Wnt signaling in human colorectal cancer cells to elucidate the additional anti-cancer mechanism of silymarin. Transient transfection with a TOP and FOP FLASH luciferase construct indicated that silymarin suppressed the transcriptional activity of ${\beta}$-catenin/TCF. Silymarin treatment resulted in a decrease of intracellular ${\beta}$-catenin protein but not mRNA. The inhibition of proteasome by MG132 and $GSK3{\beta}$ inhibition by SB216763 blocked silymarin-mediated downregulation of ${\beta}$-catenin. In addition, silymarin increased phosphorylation of ${\beta}$-catenin and a point mutation of S33Y attenuated silymarin-mediated ${\beta}$-catenin downregulation. In addition, silymarin decreased TCF4 and increased Axin expression in both protein and mRNA level. From these results, we suggest that silymarin-mediated downregulation of ${\beta}$-catenin and TCF4 may result in the inhibition of Wnt signaling in human colorectal cancer cells.

• Biomolecules & Therapeutics
• /
• 제18권4호
• /
• pp.402-410
• /
• 2010

Although the overproduction of prostaglandin $E_2$ ($PGE_2$) in intestinal epithelial cells has been considered to be highly correlated with the colorectal carcinogenesis, the precise mechanism of action remains poorly elucidated. Accumulating evidence suggests that the PGE receptor (EP)-mediated signal transduction pathway might play an important role in this process. In the present study, we investigated the mechanism of action underlying $PGE_2$-mediated cell proliferation and the effect of resveratrol on the proliferation of human colon cancer cells in terms of the modulating $PGE_2$-mediated signaling pathway. $PGE_2$ stimulated the proliferation of several human colon cancer cells and activated growth-stimulatory signal transduction, including Akt and ERK. $PGE_2$ also increased the phosphorylation of GSK-$3{\beta}$, the translocation of ${\beta}$-catenin into the nucleus, and the expressions of c-myc and cyclin D1. Resveratrol, a cancer chemopreventive phytochemical, however, inhibited $PGE_2$-induced growth stimulation and also suppressed $PGE_2$-mediated signal transduction, as well as ${\beta}$-catenin/T cell factor-mediated transcription in human colon cancer cells. These findings present an additional mechanism through which resveratrol affects the regulation of human colon cancer cell growth.

• Biomolecules & Therapeutics
• /
• 제22권5호
• /
• pp.384-389
• /
• 2014

Adiponectin, an adipokine predominantly secreted from adipose tissue, exhibits diverse biological responses, including metabolism of glucose and lipid, and apoptosis in cancer cells. Recently, adiponectin has been shown to modulate autophagy as well. While emerging evidence has demonstrated that autophagy plays a role in the modulation of proliferation and apoptosis of cancer cells, the role of autophagy in apoptosis of cancer cell caused by adiponectin has not been explored. In the present study, we demonstrated that globular adiponectin (gAcrp) induces both apoptosis and autophagy in human hepatoma cell line (HepG2 cells) and breast cancer cells (MCF-7), as evidenced by increase in caspase-3 activity, Bax, microtubule-associated protein light chain 3-II (LC3 II) protein levels, and autophagosome formation. Interestingly, gene silencing of LC3B, an autophagy marker, significantly enhanced gAcrp-induced apoptosis in both HepG2 and MCF-7 cell lines, whereas induction of autophagy by rapamycin, an mTOR inhibitor, significantly prevented gAcrp-induced apoptosis in hepatoma cells HepG2. Furthermore, modulation of autophagy produced similar effects on gAcrp-induced Bax expression in HepG2 cells. These results implicate that induction of autophagy plays a regulatory role in adiponectin-induced apoptosis of cancer cells, and thus inhibition of autophagy would be a novel promising target to enhance the efficiency of cancer cell apoptosis by adiponectin.

• IMMUNE NETWORK
• /
• 제14권6호
• /
• pp.265-276
• /
• 2014

The interactions between B7 molecules and CD28-family receptors are crucial in the regulation of adaptive cellular immunity. In cancer, the aberrant expression of co-inhibitory B7 molecules has been attributed to reduced anti-tumor immunity and cancer immune evasion, prompting the development of cancer therapeutics that can restore T cell function. Murine tumor models have provided significant support for the targeting of multiple immune checkpoints involving CTLA-4, PD-1, ICOS, B7-H3 and B7-H4 during tumor growth, and clinical studies investigating the therapeutic effects of CTLA-4 and PD-1 blockade have shown exceptionally promising results in patients with advanced melanoma and other cancers. The expression pattern of co-inhibitory B7 ligands in the tumor microenvironment has also been largely correlated with poor patient prognosis, and recent evidence suggests that the presence of several B7 molecules may predict the responsiveness of immunotherapies that rely on pre-existing tumor-associated immune responses. While monotherapies blocking T cell co-inhibition have beneficial effects in reducing tumor burden, combinatorial immunotherapy targeting multiple immune checkpoints involved in various stages of the anti-tumor response has led to the most substantial impact on tumor reduction. In this review, we will examine the contributions of B7- and CD28-family members in the context of cancer development, and discuss the implications of current human findings in cancer immunotherapy.

• Biomolecules & Therapeutics
• /
• 제25권3호
• /
• pp.337-343
• /
• 2017

Kahweol as a coffee-specific diterpene has been reported to induce apoptosis in human cancer cells. Although some molecular targets for kahweol-mediated apoptosis have been elucidated, the further mechanism for apoptotic effect of kahweol is not known. Activating transcription factor 3 (ATF3) has been reported to be associated with apoptosis in colorectal cancer. The present study was performed to investigate the molecular mechanism by which kahweol stimulates ATF3 expression and apoptosis in human colorectal cancer cells. Kahweol increased apoptosis in human colorectal cancer cells. It also increased ATF3 expression through the transcriptional activity. The responsible cis-element for ATF3 transcriptional activation by kahweol was CREB located between -147 to -85 of ATF3 promoter. ATF3 overexpression increased kahweol-mediated cleaved PARP, while ATF3 knockdown attenuated the cleavage of PARP by kahweol. Inhibition of ERK1/2 and $GSK3{\beta}$ blocked kahweol-mediated ATF3 expression. The results suggest that kahweol induces apoptosis through ATF3-mediated pathway in human colorectal cancer cells.