Interference of suppressor of cytokine signaling 3 promotes epithelial-mesenchymal transition in MHCC97H cells

Gallic acid against hepatocellular carcinoma: An integrated scheme of the potential mechanisms of action from in vivo study

The global burden of hepatocellular carcinoma is increasing; actually, it is estimated as 750,000 new cases annually. This study was initiated to emphasize the possibility that gallic acid could alleviate hepatocarcinogenesis in vivo. In this study, 40 rats were enrolled and distributed as follows; group 1 was set as negative control, while all of groups 2, 3, and 4 were orally received N-nitrosodiethylamine for hepatocellular carcinoma induction. Group 2 was left untreated, whereas groups 3 and 4 were orally treated with gallic acid and doxorubicin, respectively. The current data indicated that gallic acid administration in hepatocellular carcinoma bearing rats yielded significant decline in serum levels of alpha-fetoprotein, glypican-3, and signal transducer and activator of transcription 3 along with significant enhancement in serum suppressors of cytokine signaling 3 level. Also, gallic acid-treated group displayed significant downregulation in the gene expression levels of hepatic gamma glutamyl transferase and heat shock protein gp96. Intriguingly, treatment with gallic acid remarkably ameliorated the destabilization of liver tissue architecture caused by N-nitrosodiethylamine intoxication as evidenced by histopathological investigation. In conclusion, this study demonstrates that the hepatocarcinogenic effect of N-nitrosodiethylamine can be abrogated by gallic acid supplementation owing to its affinity to regulate signal transducer and activator of transcription 3 signaling pathway through its outstanding bioactivities including antioxidant, anti-inflammatory, apoptotic, and antitumor effects.

STAT3 and epithelial-mesenchymal transitions in carcinomas

Cellular programs coupled to cycles of epithelial–mesenchymal transitions (EMTs) play critical roles during embryogenesis, as well as during tissue development, remodeling, and repair. Research over the last decade has established the importance of an ever-expanding list of master EMT transcription factors, whose activity is regulated by STAT3 and function to stimulate the rapid transition of cells between epithelial and mesenchymal phenotypes. Importantly, inappropriate reactivation of embryonic EMT programs in carcinoma cells underlies their metastasis to distant organ sites, as well as their acquisition of stem cell-like and chemoresistant phenotypes operant in eliciting disease recurrence. Thus, targeted inactivation of master EMT transcription factors may offer new inroads to alleviate metastatic disease. Here we review the molecular, cellular, and microenvironmental factors that contribute to the pathophysiological activities of STAT3 during its regulation of EMT programs in human carcinomas.