Prolonged inhibition of hepatocellular carcinoma cell proliferation by combinatorial expression of defined transcription factors

Hepatocellular carcinoma (HCC) accounts for a large proportion of liver cancer cases and has an extremely poor prognosis. Therefore, novel innovative therapies for HCC are strongly desired. As gene therapy tools for HCC, 2 hepatic transcription factors (TF), HNF4A and HNF1A, have been used to suppress proliferation and to extinguish cancer‐specific characteristics of target cells. However, our present data demonstrated that single transduction of HNF4A or HNF1A had only a limited effect on suppression of HCC cell proliferation. Thus, in this study, we examined whether combinations of TF could show more effective antitumor activity, and found that combinatorial transduction of 3 hepatic TF, HNF4A, HNF1A and FOXA3, suppressed HCC cell proliferation more stably than single transduction of these TF. The combinatorial transduction also suppressed cancer‐specific phenotypes, such as anchorage‐independent growth in culture and tumorigenicity after transplantation into mice. HCC cell lines transduced with the 3 TF did not recover their proliferative property after withdrawal of anticancer drugs, indicating that combinatorial expression of the 3 TF suppressed the growth of all cell subtypes within the HCC cell lines, including cancer stem‐like cells. Transcriptome analyses revealed that the expression levels of a specific gene set involved in cell proliferation were only decreased in HCC cells overexpressing all 3 TF. Moreover, combined transduction of the 3 TF could facilitate hepatic differentiation of HCC cell lines. Our strategy for inducing stable inhibition and functional differentiation of tumor cells using a defined set of TF will become an effective therapeutic strategy for various types of cancers.