Novel inhibitor of OCT1 enhances the sensitivity of human esophageal squamous cell carcinoma cells to antitumor agents.

Esophageal squamous cell carcinoma (ESCC) is one of the most fatal malignancies of the digestive system, and shows an especially high incidence in some regions of China. Octamer transcription factors are a family of transcription factors whose DNA-binding domain is a POU domain. OCT transcription factors (OCT-TFs) mediate maintenance of the pluripotency of embryonic stem cells. We measured expression of OCT-TFs in ESCC clinical specimens. Among the OCTs tested, OCT1 showed the highest expression in ESCC tissues. Using molecular docking, we discovered a small-molecule inhibitor, which we named "novel inhibitor of OCT1" (NIO-1), for OCT1. Treatment with NIO-1 inhibited recruitment of OCT1 to the promoter region of its downstream genes and, consequently, repressed OCT1 activation. Treatment with NIO-1 enhanced the susceptibility of ESCC cells to chemotherapeutic agents. Therefore, OCT1 may be a valuable target for ESCC treatment, and NIO-1 could be a promising therapeutic agent.

Novel mTOR Inhibitor Enhances the Sensitivity of Hepatocellular Carcinoma Cells to Molecular Targeting Agents.

BACKGROUND: Although molecular-targeted agents are still the first choice for advanced hepatocellular carcinoma (HCC) treatment, the therapeutic efficacy of these agents is not satisfactory. Recently, the mammalian target of rapamycin (mTOR) is considered to be a promising molecular target that can enhance the sensitivity of HCC cells to antitumor therapy. However, the reported mTOR inhibitors have some shortcomings, and novel mTOR inhibitors need to be developed to enhance the antitumor effect of molecularly targeted agents on advanced HCC. METHODS: In this study, five small-molecular compounds that could serve as potential mTOR-specific inhibitors were identified by virtual screening. The activity of tert-butyl (4-(9-(2-(1,3-dioxolan-2-yl)ethyl)-6-morpholino-9H-purin-2-yl)phenyl)carbamate (compound 4) was measured by enzyme test and Western blot, and its antitumor effect on HCC was examined in nude mice subcutaneous tumor model. RESULTS: The results showed that 4 is the most effective one in inhibiting the activation of mTOR kinase (mTOR IC50 = 17.52±3.67 nmol/L) among the five lead compounds. Further research in this study indicated that treatment with 4 enhanced the sensitivity of HCC cells to the molecular-targeted agents, such as sorafenib, regorafenib, lenvatinib, anlotinib, and apatinib. In addition, this research indicated that mTOR was correlated with the poor prognosis in patients with advanced HCC who received sorafenib. CONCLUSION: Our study identified a new type of small-molecular inhibitors of mTOR and confirmed their ability to enhance the antitumor effect of molecular-targeted agents on advanced HCC.

Virtual Screening and Optimization of Novel mTOR Inhibitors for Radiosensitization of Hepatocellular Carcinoma.

BACKGROUND: Radiotherapy has an ameliorative effect on a wide variety of tumors, but hepatocellular carcinoma (HCC) is insensitive to this treatment. Overactivated mammalian target of rapamycin (mTOR) plays an important part in the resistance of HCC to radiotherapy; thus, mTOR inhibitors have potential as novel radiosensitizers to enhance the efficacy of radiotherapy for HCC. METHODS: A lead compound was found based on pharmacophore modeling and molecular docking, and optimized according to the differences between the ATP-binding pockets of mTOR and PI3K. The radiosensitizing effect of the optimized compound (2a) was confirmed by colony formation assays and DNA double-strand break assays in vitro. The discovery and preclinical characteristics of this compound are described. RESULTS: The key amino acid residues in mTOR were identified, and a precise virtual screening model was constructed. Compound 2a, with a 4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine scaffold, exhibited promising potency against mTOR (mTOR IC50=7.1 nmol/L (nM)) with 126-fold selectivity over PI3Kα. Moreover, 2a significantly enhanced the sensitivity of HCC to radiotherapy in vitro in a dose-dependent manner. CONCLUSION: A new class of selective mTOR inhibitors was developed and their radiosensitization effects were confirmed. This study also provides a basis for developing mTOR-specific inhibitors for use as radiosensitizers for HCC radiotherapy.

Correlation between expression of matrix metalloproteinase-2 and angiogenesis in esophageal carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study expression of MMP-2 in relation to microvessel density (MVD) in esophageal carcinoma.</p><p><b>METHODS</b>Forty-eight specimens of esophageal carcinoma (Ec) and 17 specimens of grade II + III epithelial dysplasia (Dy) close to the tumor and 12 specimens of normal tissue (Nt) along the incisional margin were examined by S-P immunohistochemical staining with anti-MMP-2 monoclonal antibody. An anti-CD34 monoclonal antibody was used to show MVD.</p><p><b>RESULTS</b>MMP-2 expression in Ec was remarkably higher than that in Dy, which was higher than that in Nt. MMP-2 expression in Ec and Dy was significantly correlated with MVD in the tumor and nearby tissue. MMP-2 expression and MVD in Ec significantly associated with lymph node metastasis.</p><p><b>CONCLUSION</b>Expression of MMP-2 plays an important role in angiogenesis and lymph node metastasis of esophageal cancer.</p>

Effects of ginsenoside Rh2(GS-Rh2) on cell cycle of Eca-109 esophageal carcinoma cell line / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the effects of ginsenoside Rh2 (GS-Rh2) on growth inhibition and cell cycle of Eca-109 esophageal carcinoma cell line in culture.</p><p><b>METHOD</b>The effects of GS-Rh2 on cell growth inhibition was detected by MTT assay. Cell cycle was analyzed by flow cytometry (FCM). Cell morphology was observed by a light microscope after HE staining. The protein expression of cell cycle components (cyclinE, CDK2, p21WAF1) were examined by immunocytochemistry and Western blot. The mRNA expression were examined by semiquantitative RT-PCR.</p><p><b>RESULT</b>GS-Rh2 inhibited the proliferation of Eca-109 cells in dose and time-dependent manners. The inhibition rate was about 50% after 1-day treatment with 20 microg x mL(-1) GS-Rh2 x 20 microg x mL(-1) GS-Rh2 induced the mature differentiation and morphological reversion. With increasing dose of GS-Rh2 treatment, the cell number of G0/G1 phase was increased, whereas it decreased at S and G2/M phase. There was significant difference between 10, 20 microg x mL(-1) GS-Rh2 groups and the corresponding group without GS-Rh2 treatement. After treating cells by 20 microg x mL(-1) GS-Rh2 for 1, 2, 3 days individually, the protein and mRNA expression of both cyclinE and CDK2 reduced, while the expression of p21WAF1 enhanced gradually.</p><p><b>CONCLUSION</b>GS-Rh2 could arrest Eca-109 cells at G0/G1 phase and induce cell differentiation tending to normal. Furthermore, GS-Rh2 had an effect on expression of cell cycle components (cyclinE, CDK2 and p21WAF1) to inhibit Eca-109 cell proliferation.</p>