PTEN enhances the sensitivity of human hepatocellular carcinoma cells to sorafenib

Hepatocellular carcinoma (HCC) is a complex and heterogeneous tumor with several genomic alterations and ranks as the third highest cause of cancer-related death globally. The unresectable or metastatic HCC has very poor prognosis. Although multikinase inhibitor sorafenib can increase the survival of patients with advanced HCC, it is becoming apparent that combination therapies are critical to overcome the complex genomic aberrations in HCC. PTEN, as one of the most commonly inactivated genes in HCC, exerts a wide range of antitumor effects. In this study, we found that PTEN was downregulated in HCC tissues, especially in those tissues with extrahepatic metastasis. And negative PTEN expression cases showed increased proliferation activity. Overexpression of PTEN significantly reduced the proliferation of tumor cells HepG2. In addition, HepG2 cells transfected with PTEN were more sensitive to sorafenib in terms of its ability to inhibit proliferation and to induce apoptosis. Moreover, overexpression of PTEN decreased phosphorylation of MEK, a key downstream effector of RAF/MEK/ERK cascade, and levels of cyclin D1, antiapoptotic Bcl-2, and VEGF. These observations indicated that combination therapies with sorafenib and PTEN overexpression have potential to further improve therapeutic options for HCC.