Jinfeng Xiao

SIRT1 promotes tumorigenesis of hepatocellular carcinoma through PI3K/PTEN/AKT signaling

SIRT1 is the human orthologue of SIR2, a conserved NAD-dependent protein deacetylase that regulates longevity in yeast and in Caenorhabditis elegans. Overexpression of SIRT1 in cancer tissue, compared with normal tissue, has been demonstrated, suggesting that SIRT1 may act as a tumor promoter. The function of SIRT1 in liver cancer has not been elucidated. In the present study, SIRT1 re-expression or knockdown was induced in hepatoma cell lines and liver normal cell lines. Our study demonstrated that overexpression of SIRT1 promoted mitotic entry of liver cells, cell growth and proliferation and inhibited apoptosis. The apoptosis involved caspase-3 and caspase-7, and was related to the PTEN/PI3K/AKT signaling pathway. The results demonstrate that SIRT1 promotes tumorigenesis of hepatocellular carcinoma (HCC) through the PTEN/PI3K/AKT signaling pathway. SIRT1 may serve as a novel target for selective killing of cancer versus normal liver cells.

Increased survival in hepatocellular carcinoma with iodine-125 implantation plus radiofrequency ablation: A prospective randomized controlled trial

BACKGROUND & AIMS The purpose of this study was to evaluate whether use of combined radiofrequency ablation (RFA) and percutaneous iodine-125 ((125)I) seed implantation results in better progression-free survival compared with the use of RFA alone in patients with hepatocellular carcinoma. METHODS 136 patients were randomly assigned to undergo HCC treatment with RFA and percutaneous iodine-125 seed implantation (RFA-(125)I, n=68) or RFA-only (n=68). A total of 91 patients had hepatitis B viral infection in both groups. Rates of tumour recurrence and overall survival were evaluated. RESULTS The probabilities of recurrence at 1-, 3-, and 5-years were 4.5%, 22.1%, and 39.8% in the RFA-(125)I group; and 14.8%, 35.3%, and 57.4% in the RFA-only group, respectively. The recurrence rate in the RFA-(125)I group was significantly lower than in the RFA-only group (HR, 0.508; 95% CI, 0.317-0.815; p=0.004 by log-rank test). Local and intrahepatic recurrence was significantly lower in the RFA-(125)I group than in the RFA-only group (7.3% vs. 22.0%, p=0.012 by log-rank test; 17.6% vs. 32.3%, p=0.041 by log-rank test). The probabilities of survival at 1-, 3-, and 5-years were 100%, 86.7%, and 66.1% in the RFA-(125)I group and 95.6%, 75.0%, and 47.0% in the RFA-only group, respectively. The survival rate in the RFA-(125)I group was significantly better than in the RFA-only group (HR, 0.502; 95% CI, 0.313-0.806; p=0.003 by log-rank test). Cox regression model indicated that the treatment group and tumour size were both recurrence-related and overall survival-related prognostic factors. CONCLUSIONS There were significant differences in overall survival and cumulative recurrence between RFA-(125)I and RFA-only for patients with small HCCs (⩽3 cm). Treatment with RFA-(125)I facilitated better local and intrahepatic tumour control and long-term survival compared with treatment of RFA alone. ClinicalTrials.gov Identifier: NCT01717729.

Crocetin induces apoptosis of BGC-823 human gastric cancer cells.

Gastric cancer (GC) is one of the most common types of gastrointestinal tumors worldwide, and the side effects of chemotherapeutic drugs and the resistance to chemotherapy remain problematic in its clinical treatment. Therefore, safe and effective novel agents are urgently required. The purpose of the present study was to investigate the crocetin‑sensitive treatment of GC and its possible mechanisms. BGC‑823 human GC cells were treated with crocetin. The effects of crocetin on the viability of the cells were determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Hoechst 33258 dyeing and Rh123 staining were used to detect cell apoptosis. The BGC‑823 cells were subjected to western blotting analysis for detection of cytochrome c and cleaved caspase‑3 protein expression. Crocetin inhibited the proliferation of the GC cell line in a dose‑ and time‑dependent manner. Apoptotic BGC‑823 cells induced by crocetin were stained by Hoechst 33258 and observed under a light microscope for cell membrane staining of dense nuclei, nuclear pyknosis, fragmentation, chromatin condensation and highlighted nuclear membrane staining. This revealed a decline in the mitochondrial membrane potential of the BGC‑823 cells. Crocetin also induced caspase‑3 activation and cytochrome c translocation into the cytosol from the mitochondria. The results of this study indicate that crocetin induces the apoptosis of BGC‑823 cells, and may be used as an effective agent in the treatment of GC.

Highly expressed MT-ND3 positively associated with histological severity of hepatic steatosis

Hepatic steatosis is the accumulation of an excess amount of triglycerides and other fats inside liver cells resulting from abnormal hepatic lipid metabolism. Mitochondrial structural and molecular defects are involved in the progression of hepatic steatosis pathogenesis. Hepatic methylation and transcriptional activity of the mitochondrial‐encoded NADH dehydrogenase (MT‐ND) play a critical role in the progression of non‐alcoholic fatty liver disease (NAFLD). However, the expression of MT‐ND3 in hepatic steatosis has not been extensively studied. In this study, liver specimens were collected from different patients, and were subjected to immunohistochemistry. Primary hepatocytes were treated with oxidative stress, hypoxia, and lipotoxicity to investigate the respective roles of these factors on MT‐ND3 expression and cell apoptosis by western blotting and flow cytometry, respectively. We found that increased MT‐ND3 expression in human hepatic steatosis was positively associated with histological severity of hepatic steatosis. Hypoxia, H2O2, and saturated fatty acid treatment induced cell apoptosis mediated by mitochondria. These three factors all had effects on MT‐ND3 expression in cultured hepatocytes. Taken together, MT‐ND3 may play important roles in hepatic steatosis progress. Hypoxia, oxidative stress, and lipotoxicity could all influence expression of MT‐ND3 and thus may play a role in the progression of hepatic steatosis.

Histone deacetylase inhibitor screening identifies HC toxin as the most effective in intrahepatic cholangiocarcinoma cells

Histone deacetylases (HDACs) are highly expressed in intrahepatic cholangiocarcinoma (ICC) and are associated with poor prognosis of these patients. The aim of the present study was to explore the inhibitory effects of HDAC inhibitors on ICC cells and identify effective and sensitive drugs for ICC. Effects of 34 HDAC inhibitors were screened through two rounds of cell viability assays, and HC toxin, a cyclic tetrapeptide first isolated from the secondary metabolite of Helminthosporium carbonum, exhibited an antitumor activity superior to that of the other HDAC inhibitors and gemcitabine. The mechanisms involved in the inhibitory effects of HC toxin on CCLP-1 cells were investigated by cell counting, colony formation assay, cell morphological observation, real-time PCR, western blotting and flow cytometry. It was demonstrated that HC toxin inhibited the cell proliferation and clone formation ability of the CCLP-1 cells. HC toxin increased the acetyl-histone H4 level and this was associated with the inhibitory effect of HC toxin on the CCLP-1 cells. We also found that HC toxin reduced the level of HDAC1 protein in a post-transcriptional manner. Morphological observation showed multiple morphological changes and indicated the possibility of cell differentiation owing to HC toxin. With increasing concentration of HC toxin, the cell cycle was gradually arrested at the G0/G1 stage and the percentage of apoptotic cells increased which was not mainly through the caspase-3-dependent ways. These results indicated that HC toxin was the most effective among the various HDAC inhibitors with multiple functions in the suppression of ICC in vitro. Thus, HC may be a potential chemotherapeutic for ICC.

Proapoptotic Role of Potassium Ions in Liver Cells

Potassium channels are transmembrane proteins that selectively promote the infiltration of potassium ions. The significance of these channels for tumor biology has become obvious. However, the effects of potassium ions on the tumor or normal cells have seldom been studied. To address this problem, we studied the biological effects of L02 and HepG2 cells with ectogenous potassium ions. Cell proliferation, cell cycle, and apoptosis rate were analyzed. Our results indicated that potassium ions inhibited proliferation of L02 and HepG2 cells and promoted their apoptosis. Potassium ions induced apoptosis through regulating Bcl-2 family members and depolarized the mitochondrial membrane, especially for HepG2 cell. These biological effects were associated with channel protein HERG. By facilitating expression of channel protein HERG, potassium ions may prevent it from being shunted to procancerous pathways by inducing apoptosis. These results demonstrated that potassium ions may be a key regulator of liver cell function. Thus, our findings suggest that potassium ions could inhibit tumorigenesis through inducing apoptosis of hepatoma cells by upregulating potassium ions transport channel proteins HERG and VDAC1.