Background/Aims: TGF-β plays a key role in the progression of various tumors. The main objective of our study was to investigate whether TGF-β is able to regulate N-nitrosodiethylamine (DEN)-induced hepatocellular carcinoma (HCC) progression in a mouse model by inducing Treg cell polarization. Methods: HCC progression, TGF-β and Foxp3 expression levels, serum TGF-β, IL10 and GP73 levels as well as percentage of Treg cells were analyzed in healthy, HCC and HCC+SM-16 mouse groups. The effect of TGF-β on Treg cell polarization in vitro was measured by flow cytometric analysis. The expression of TGF-β and IL10 was identified by IHC in HCC patients and the correlation between TGF-β and IL10 was also assessed. Results: TGF-β expression is up-regulated in a DEN-induced HCC mouse model. TGF-β can promote the differentiation of Foxp3⁺CD4⁺ T cells (Treg cells) in vitro. However, blocking the TGF-β pathway with a specific TGF-β receptor inhibitor, SM-16, reduced HCC progression and the percentage of Treg cells in liver tissue. The correlation between TGF-β and Treg cells was also confirmed in HCC patients and the expression of both TGF-β and IL-10 was shown to be associated with HCC progression. Conclusion: TGF-β is necessary for HCC progression, acting by inducing Treg cell polarization.

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Systemic chemotherapy plays an important role in the treatment of patients with advanced liver cancer. However, chemoresistance to cisplatin is a major limitation of cisplatin-based chemotherapy in the clinic, and the underlying mechanism of such resistance is not fully understood. In this study, we found that nuclear accumulation of β-catenin was higher in cisplatin-resistant Huh7 cells than in Huh7 cells, indicating that Wnt signaling was activated in cisplatin-resistant cells. Wnt signaling inhibition increased cisplatin-induced growth inhibition in hepatoma cell. We further demonstrated that sorafenib could inhibit Wnt signaling in Huh7 cells and cisplatin-resistant Huh7 cells. Co-treatment with cisplatin and sorafenib was more effective in inhibiting cancer cell proliferation than cisplatin alone in vitro and in vivo, whereas Wnt3a (Wnt activator) treatment abrogated sorafenib-induced growth inhibition. These data demonstrated that sorafenib sensitizes human HCC cell to cisplatin via suppression of Wnt/β-catenin signaling, thus offering a new target for chemotherapy of HCC.