• Development and Reproduction
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• v.18 no.4
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• pp.225-231
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• 2014

Autophagy is a homeostatic degradation process that is involved in tumor development and normal development. Autophagy is induced in cancer cells in response to chemotherapeutic agents, and inhibition of autophagy results in enhanced cancer cell death or survival. Chloroquine (CQ), an anti-malarial drug, is a lysosomotropic agent and is currently used as a potential anticancer agent as well as an autophagy inhibitor. Here, we evaluate the characteristics of these dual activities of CQ using human colorectal cancer cell line HCT15. The results show that CQ inhibited cell viability in dose- and time-dependent manner in the range between 20 to 80 uM, while CQ did not show any antiproliferative activity at 5 and 10 uM. Cotreatment of CQ with antitumor agent NVP-BEZ235, a dual inhibitor of PI3K/mTOR, rescued the cell viability at low concentrations meaning that CQ acted as an autophagy inhibitor, but CQ induced the lethal effect at high concentrations. Acridine orange staining revealed that CQ at high doses induced lysosomal membrane permeabilization (LMP). High doses of CQ produced cellular reactive oxygen species (ROS) and cotreatment of antioxidants, such as NAC and trolox, with high doses of CQ rescued the cell viability. These results suggest that CQ may exert its dual activities, as autophagy inhibitor or LMP inducer, in concentration-dependent manner.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4651-4657
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• 2014

The development of chemopreventive approaches using a concoction of phytochemicals is potentially viable for combating many types of cancer including colon carcinogenesis. This study evaluated the anti-proliferative effects of ginger and Gelam honey and its efficacy in enhancing the anti-cancer effects of 5-FU (5-fluorouracil) against a colorectal cancer cell line, HCT 116. Cell viability was measured via MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulphenyl)-2H-tetrazolium) assay showing ginger inhibiting the growth of HCT 116 cells more potently ($IC_{50}$ of 3mg/mL) in comparison to Gelam honey ($IC_{50}$ of 75mg/mL). Combined treatment of the two compounds (3mg/mL ginger+75mg/mL Gelam honey) synergistically lowered the $IC_{50}$ of Gelam honey to 22mg/mL. Combination with 35 mg/mL Gelam honey markedly enhanced 5-FU inhibiting effects on the growth of HCT 116 cells. Subsequent analysis on the induction of cellular apoptosis suggested that individual treatment of ginger and Gelam honey produced higher apoptosis than 5-FU alone. In addition, treatment with the combination of two natural compounds increased the apoptotic rate of HCT 116 cells dose-dependently while treatment of either ginger or Gelam honey combined with 5-FU only showed modest changes. Combination index analysis showed the combination effect of both natural compounds to be synergistic in their inhibitory action against HCT 116 colon cancer cells (CI 0.96 < 1). In conclusion, combined treatment of Gelam honey and ginger extract could potentially enhance the chemotherapeutic effect of 5-FU against colorectal cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.10015-10020
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• 2014

Background: Fentanyl is used as an analgesic to treat pain in a variety of patients with cancer and recently it has become considered to also act as an antitumor agent. The study present was designed to investigate the effects of fentanyl on colorectal cancer cell growth and plausible mechanisms. Materials and Methods: The human colorectal carcinoma cell line HCT116 was subcutaneously injected into nude mice. The viability of HCT116 was tested by MTT assay, and apoptosis by flow cytometry and caspase-3 activity. The expression of Sirt1 and NF-${\kappa}B$ were evaluated by Western blotting and the levels of Sirt1 and NF-${\kappa}B$ by fluorescence method. SiRNA was used to silence and Ad-Sirt1 to overexpress Sirt1. Results: Our data showed that fentanyl could inhibit tumor growth, with increased expression of Sirt1 and down-regulation of Ac-p65 in tumors. Compared with control cells without treatment, HCT116 cells that were incubated with fentanyl had a higher apoptotic rate. Moreover, fentanyl could increase expression and activity of Sirt1 and inhibitor expression and activity of NF-${\kappa}B$, which might be mechanisms of fentanyl action. Conclusions: Fentanyl increased colorectal carcinoma cell apoptosis by inhibition of NF-${\kappa}B$ activation in a Sirt1-dependent manner.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2911-2916
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• 2014

Oxaliplatin is a first-line therapy for colorectal cancer, but cancer cell resistance to the drug compromises its efficacy. To explore mechanisms of drug resistance, we treated colorectal cancer cells (HCT116 and SW620) long-term with oxaliplatin and established stable oxaliplatin-resistant lines (HCT116-OX and SW620-OX). Compared with parental cell lines, $IC_{50}$s for various chemotherapeutic agents (oxaliplatin, cisplatin and doxorubicin) were increased in oxaliplatin-resistant cell lines and this was accompanied by activation of nuclear factor erythroid-2 p45-related factor 2 (Nrf2) and NADPH quinone oxidoreductase 1 (NQO1). Furthermore, luteolin inhibited the Nrf2 pathway in oxaliplatin-resistant cell lines in a dose-dependent manner. Luteolin also inhibited Nrf2 target gene [NQO1, heme oxygenase-1 (HO-1) and $GST{\alpha}1/2$] expression and decreased reduced glutathione in wild type mouse small intestinal cells. There was no apparent effect in Nrf2-/- mice. Luteolin combined with other chemotherapeutics had greater anti-cancer activity in resistant cell lines (combined index values below 1), indicating a synergistic effect. Therefore, adaptive activation of Nrf2 may contribute to the development of acquired drug-resistance and luteolin could restore sensitivity of oxaliplatin-resistant cell lines to chemotherapeutic drugs. Inhibition of the Nrf2 pathway may be the mechanism for this restored therapeutic response.

• Development and Reproduction
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• v.20 no.1
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• pp.1-10
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• 2016

Molecular targeting for the altered signaling pathways has been proven to be effective for the treatment of many types of human cancer, including colorectal cancer (CRC). The dual phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitor BEZ235 has shown to exhibit potent antitumor activity against solid tumors. Autophagy is a cellular lysosomal catabolic process to maintain metabolic homeostasis, which has been known to be induced in response to many therapeutic agents in cancer cells. This process is negatively regulated by mTOR and often acts as prosurvival or prodeath mechanism following cancer therapeutics. The current study was designed to investigate the antiproliferation activity of BEZ235 and to evaluate the role of autophagy induced by BEZ235 using HCT15 CRC cells bearing ras oncogene mutation. We found that BEZ235 decreases cell viability, which was mostly dependent on $G_1$ arrest of cell cycle via suppression of cyclin A expression. BEZ235 affects PI3K/Akt/mTOR signaling pathway by increasing the phosphorylation of AKT at $Ser^{473}$ and RAS/RAF/MEK/ERK pathway by decreasing the phosphorylation of ERK at $Tyr^{204}$. BEZ235 also stimulated autophagy induction as evidenced by the increased expression of LC3-II and abundant acidic vesicular organelles (AVOs) in the cytoplasm. In addition, the combination of BEZ235 with autophagy inhibitor chloroquine, a known antagonist of autophagy, counteracted the antiproliferation effect of BEZ235. Thus, our study indicates that autophagy induced in response to BEZ235 treatment appears to act as cell death mechanism in HCT15 CRC cells.

• IMMUNE NETWORK
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• v.12 no.2
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• pp.66-69
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• 2012

The immunological death induction by EY-6 on the human tumor cell lines was screened. Human colon carcinoma (HCT15, HCT116), gastric carcinoma (MKN74, SNU668), and myeloma (KMS20, KMS26, KMS34) cells were died by EY-6 treatment with dose-dependent manner. CRT expression, a typical marker for the immunological death, was increased on the EY-6-treated colorectal and gastric cancer cells. Interestingly, the effects on the myeloma cell lines were complicated showing cell line dependent differential modulation. Cytokine secretion from the EY-6 treated tumor cells were dose and cell-dependent. IFN-${\gamma}$ and IL-12 secretion was increased in the treated cells (200% to over 1000% of non-treated control), except HCT116, SNU668 and KMS26 cells which their secretion was declined by EY-6. Data suggest the potential of EY-6 as a new type of immuno-chemotherapeutics inducing tumor-specific cell death. Further studies are planned to confirm the efficacy of EY-6 including in vivo study.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.8
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• pp.4019-4023
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• 2016

Background: Colorectal cancer (CRC) or bowel cancer is one of the most important cancer diseases, needing serious attention. The cell surface receptor gene human epidermal growth factor receptor (EGFR) may have an important role in provoking CRC. In this pharmaceutical era, it is always attempted to identify plant-based drugs for cancer, which will have less side effects for human body, unlike the chemically synthesized marketed drugs having serious side effects. So, in this study the authors tried to assess the activity of two important plant compounds, ferulic acid (FA) and p-coumaric acid (pCA), on CRC. Materials and Methods: FA and pCA were tested for their cytotoxic effects on the human CRC cell line HCT 15 and also checked for the level of gene expression of EGFR by real time PCR analysis. Positive results were confirmed by in silico molecular docking studies using Discovery Studio (DS) 4.0. The drug parallel features of the same compounds were also assessed in silico. Results: Cytotoxicity experiments revealed that both the compounds were efficient in killing CRC cells on a controlled concentration basis. In addition, EGFR expression was down-regulated in the presence of the compounds. Docking studies unveiled that both the compounds were able to inhibit EGFR at its active site. Pharmacokinetic analysis of these compounds opened up their drug like behaviour. Conclusions: The findings of this study emphasize the importance of plant compounds for targeting diseases like CRC.