Highly efficient conversion of mouse fibroblasts into functional hepatic cells under chemical induction.

Previous studies have shown that hepatocyte-like cells can be generated from fibroblasts using either lineage-specific transcription factors or chemical induction methods. However, these methods have their own deficiencies that restrict the therapeutic applications of such induced hepatocytes. In this study, we present a transgene-free, highly efficient chemical-induced direct reprogramming approach to generate hepatocyte-like cells from mouse embryonic fibroblasts (MEFs). Using a small molecule cocktail (SMC) as an inducer, MEFs can be directly reprogrammed into hepatocyte-like cells, bypassing pluripotent and immature hepatoblast intermediate stages. These chemical-induced hepatocyte-like cells (ciHeps) closely resemble mature primary hepatocytes in terms of morphology, biological behavior, gene expression patterns, marker expression levels, and hepatic functions. Furthermore, transplanted ciHeps can integrate into the liver, promote liver regeneration, and improve survival rates in mice with acute liver damage. ciHeps can also ameliorate liver fibrosis caused by chronic injuries and enhance liver function. Notably, ciHeps exhibit no tumorigenic potential either in vitro or in vivo. Mechanistically, SMC-induced mesenchymal-to-epithelial transition and suppression of SNAI1 contribute to the fate conversion of fibroblasts into ciHeps. These results indicate that this transgene-free, chemical-induced direct reprogramming technique has the potential to serve as a valuable means of producing alternative hepatocytes for both research and therapeutic purposes. Additionally, this method also sheds light on the direct reprogramming of other cell types under chemical induction.

Small Molecule-Induced Differentiation As a Potential Therapy for Liver Cancer.

Despite the efficacy demonstrated by immunotherapy recently, liver cancer still remains one of the deadliest cancers, mainly due to heterogeneity of this disease. Continuous exploration of new therapeutics is therefore necessary. Chemical-induced cell differentiation can serve as a promising approach, with its ability to consistently remodel gene expression profile and alter cell fate. Inspired by advances in stem cell and reprogramming field, here it is reported that a small molecule cocktail (SMC) consisted of: SB431542 (TGFß inhibitor), CHIR99021 (GSK3ß inhibitor), BIX01294 (H3K9 methyltransferase/G9a inhibitor), and all-trans retinoic acid (ATRA), can induce differentiation of liver cancer cells including cell lines, primary cancer cells, cancer stem cells, and drug resistant cells. Treated cells lose malignant characteristics and regain hepatocyte phenotype instead. When applied in vivo, SMC induces wide range of tissue necrosis or fibrosis within the tumors, while remaining tissues begin to express hepatic nuclear factor 4α (HNF4α), the hepatic nuclear marker. SMC also leads to tumor abrogation in orthotopic xenograft models and life span extension of animals. The powerful differentiation induction of SMC is exerted through modulation of Akt/mTOR/HIF1α signaling and metabolic reprogramming, as well as suppressing Snail and enhancing HNF4α expression. Together, these results highlight that chemical-induced differentiation has the potential to effectively treat liver cancer disregard of heterogeneity.