New Experimental Mouse Models to Evaluate the Role of Transforming Growth Factor-Beta in Liver Tumorigenesis.

[BACKGROUND AND AIMS] Hepatocellular carcinoma (HCC) has a poor prognosis and limited treatment options. TGF-β is a promising therapeutic target, but its dual role, as both a tumour suppressor and promoter, complicates its clinical application. While its effects on tumour cells are increasingly understood, its impact on the tumour stroma remains unclear. This study developed novel in vitro and in vivo mouse models to investigate the role of TGF-β in tumour-stroma interactions under immunocompetent conditions, aiming to evaluate its therapeutic potential in liver cancer.

[METHODS] Mouse liver tumour cell lines were established by hydrodynamic tail vein injection of two different combinations of transposon vector constructions: MYC-LucOS;CTNNB1;SB13 (AL1099 cells) and MYC-Luc;CTNNB1;SB13 (AL1184 cells) to be used in in vitro and in vivo studies.

[RESULTS] These cell lines exhibited contrasting phenotypes and responses to TGF-β. We selected AL1099 cells, which displayed an epithelial phenotype and responded to TGF-β with growth inhibition, apoptosis, and induction of Epithelial-Mesenchymal Transition (EMT), and AL1184 cells, which exhibited a mesenchymal-like phenotype and showed enhanced proliferation in response to TGF-β. Both cell lines demonstrated robust growth in 2D and 3D cultures and were co-cultured with RAW 264.7 macrophages, GRX hepatic stellate cells, or both, to explore tumour-stroma interactions. Importantly, AL1099 and AL1184 cells were able to grow in vivo, forming tumours in syngeneic orthotopic models suitable for pharmacological studies.

[CONCLUSIONS] Together, these findings highlight the value of these models for advancing therapeutic strategies targeting TGF-β, either alone or in combination with immunotherapy, in liver cancer.