S-Adenosylmethionine suppresses the expression of Smad3/4 in activated human hepatic stellate cells via Rac1 promoter methylation.

The aim of the present study was to investigate whether S-adenosylmethionine (SAM) was able to suppress activated human hepatic stellate cells (HSCs). Human LX-2 HSCs were cultured with SAM or NSC23766, and were transfected with plasmids encoding ras-related C3 botulinum toxin substrate 1 (Rac1) protein or an empty expression vector. Cell proliferation was detected by Cell Counting Kit-8. Cell migration and invasion were determined using the Transwell assay. The expression levels of Rac1 and Smad3/4 were detected by reverse transcription­quantitative polymerase chain reaction (PCR) or western blotting. The methylation status of Rac1 promoters was measured by methylation­specific PCR. The results demonstrated that SAM and NSC23766 suppressed the expression of Smad3/4 in LX­2 cells. The overexpression of Rac1 enhanced the proliferation, migration and invasion of LX­2 cells. In addition, compared with the control groups, a marked increase was observed in the protein expression levels of Smad3/4 in the LX­2 cells transfected with Rac1 plasmids. The methylation-specific PCR findings showed that SAM increased the methylation of Rac1 promoters. The results of the present study suggested that Rac1 enhanced the expression of Smad3/4 in activated HSCs; however, this increase may be suppressed by SAM-induced methylation of Rac1 promoters.

Green tea and liver cancer risk: A meta-analysis of prospective cohort studies in Asian populations.

OBJECTIVES: The aim of this meta-analysis was to investigate whether an association existed between green tea consumption and the risk for liver cancer in prospective cohort studies in Asian populations. METHODS: Relevant studies were identified by searching PubMed, EMBASE, ISI Web of Science, and the Chinese Bio-medicine Database published before April 2015. Study-specific risk estimates for the highest versus non- or lowest and increment of daily cup of green tea consumption levels were combined based on fixed- or random-effects models. STATA 11.0 (Stata Corporation, College Station, TX, USA) software was used for statistical analysis. RESULTS: Nine prospective cohort articles involving 465,274 participants and 3694 cases of liver cancer from China, Japan, and Singapore were included. The summary relative risk (RR) indicated a significant association between the highest green tea consumption and reduced risk for liver cancer (summary RR, 0.88; 95% confidence interval [CI], 0.81-0.97). However, no statistically significant association was observed when analyzing daily consumption of one cup (summary RR, 0.97; 95% CI, 0.95-1.00). When stratified by sex, the protective effect of green tea consumption on risk for liver cancer was observed only in the group of women (summary RR, 0.78; 95% CI, 0.64-0.96), but not in men (summary RR, 0.89; 95% CI, 0.79-1.00). CONCLUSIONS: The present analysis indicated the preventive effects of green tea intake on the risk for liver cancer in female Asian populations. However, additional studies are needed to make a convincing case for this association.

Metformin inhibits gastric cancer via the inhibition of HIF1α/PKM2 signaling.

Recent evidence suggests that anti-diabetic drug metformin prevents cancer progression, but the mechanism by which metformin inhibits tumor growth remains elusive. In this study, we investigated the anticancer role of metformin in gastric cancer and explored the underlying mechanism. The expression of hypoxia inducible factor 1α (HIF1α) and pyruvate kinase M2 (PKM2) in different stages of gastric cancer tissues was detected by immunohistochemistry. Gastric cancer cell viability was evaluated by CCK-8 assay; apoptosis and cell cycle were analyzed by flow cytometry. The expression of PI3K, Akt, HIF1α, PARP, PKM2 and COX in gastric cancer cells was detected by immunofluorescence and Western blot analysis. We found that HIF1α and PKM2 protein expression levels were higher in advanced gastric cancer tissues than in gastritis tissues. Metformin reduced gastric cancer cell viability, invasion and migration. Metformin induced apoptosis and cell cycle arrest in part through inhibiting PARP expression. Metformin downregulated PI3K, Akt, HIF1α, PARP, PKM2 and COX expression. Moreover, overexpression of HIF1α increased gastric cancer cell viability, invasion and migration. In summary, metformin has profound antitumor effect for gastric cancer by inducing intrinsic apoptosis via the inhibition of HIF1α/PKM2 signaling pathway.

Report of China's innovation increase and research growth in radiation oncology.

AIMS: To investigate the research status of radiation oncology in China through survey of literature in international radiation oncology journals and retrospectively compare the outputs of radiation oncology articles of the three major regions of China-Mainland (ML), Taiwan (TW) and Hong Kong (HK). METHODS: Radiation oncology journals were selected from "oncology" and "radiology, nuclear & medical image" category from Science Citation Index Expand (SCIE). Articles from the ML, TW and HK were retrieved from MEDLINE. The number of total articles, clinical trials, case reports, impact factors (IF), institutions and articles published in each journals were conducted for quantity and quality comparisons. RESULTS: A total 818 articles from 13 radiation oncology journals were searched, of which 427 are from ML, 259 from TW, and 132 from HK. Ninety-seven clinical trials and 5 case reports are reported in China. Accumulated IF of articles from ML (1,417.11) was much higher than that of TW (1,003.093) and HK (544.711), while the average IF of articles from ML is the lowest. CONCLUSIONS: The total number of articles from China especially ML increased significantly in the last decade. The number of articles published from the ML has exceeded those from TW and HK. However, the quality of articles from TW and HK is better than that from ML.