In this study, we found that Transglutaminase 2 (TG2) may be involved in mediating CAFs-induced EMT in HCC cells. The signaling pathways involved in regulation of TG2 expression, as well as those underlying its tumour-promoting effect in HCC were analyzed.

Methods: HCC cells were induced to EMT by separately co-cultured with CAFs (isolated from HCC) in a transwell system. EMT markers and protein expression level were assessed by western blot. TG2 were either overexpressed or silenced by lentivirus transfection in HCC cells, and in vitro cell behavior assay and in vivo metastasis assay were performed. HGF Selleckchem EPZ 6438 and IL-6 signaling pathways were analyzed to determine whether they were involved in regulation of TG2 expression. Additionally, to explore whether TG2 could be an important factor in determining clinical outcomes of HCC, an immunohistochemical examination of TG2 expression and a clinicopathological analysis were performed in 108 consecutive HCC patients. Results: TG2 were significantly elevated Estrogen antagonist expression in HCC cells with EMT phenotype. Overexpression of TG2 promoted EMT and metastasis of HCC cells in vitro and in vivo. Knockdown of TG2 in HCC cells remarkably attenuated its EMT which induced by CAFs, as well as the migratory and invasive ability. Signaling

pathway assay showed that expression of TG2 was affected by IL-6/STAT3 activation, but not HGF/Met. Further, inhibition of the phos-phorylation of STAT3 decreased the expression of TG2 in HCC cells. These results suggest that CAFs facilitates HCC metastasis by promoting EMT via IL-6/STAT3/TG2-dependent pathway. Consistently, as disclosed by immunohistochemistry

results, high TG2 expression was significantly correlated to tumor size (P=0.027), clinical stage (P=0.018) and vascular invasion (P=0.022). Moreover, Kaplan-Meier analysis and multivariate analysis indicated that high TG2 expression associated with unfavorable overall survival (P<0.001), it was an independent poor prognostic marker for overall survival (P=0.043) of HCC patients. Conclusions: TG2 plays an important role in HCC invasion and metastasis and may serve as a novel prognostic biomarkerand much therapeutic target. Keywords: TG2; EMT; HCC; CAFs; IL-6/STAT3 signaling Disclosures: The following people have nothing to disclose: Wei Liu, Guan-zhong Chen, Kun-hua Hu, Guo-Ying Wang, Bin-sheng Fu, Qi Zhang, Gui-Hua Chen Background: Therapeutic selectivity is highly desired property for anticancer medicines. The ideal agent should be toxic to malignant cells with minimum harm to normal cells. To date, most chemotherapeutics indiscriminately damage both cancer and healthy cells resulting in severe adverse effects.