Poorly Differentiated Hepatocellular Carcinoma Cells Avoid Apoptosis by Interacting with T Cells via CD40–CD40L Linkage

Hepatocellular carcinoma (HCC) is associated with elevated soluble CD40 levels in our previous study. Here we aimed to investigate CD40's role in liver tumor progression. We examined CD40 levels in HCC patient tissues and various HCC cell lines, studying their interaction with CD4+T cells. RNA sequencing analysis was performed to explore the mechanisms of CD40 induction. Poorly differentiated HCC tumour tissues exhibited high membrane-bound CD40 (mCD40) expression, in contrast to non-tumour areas. Poorly differentiated HCC cell lines showed high expression of mCD40 with low CD40 promoter methylation which were opposite of well-differentiated ones. Solely modulating CD40 expression in HCC cells exerted no direct consequences on cell growth or appearance. Interestingly, HLFs co-cultured with activated (CD40L+) CD4+ T cells elevated CD40 levels and showed a modest 3.2% of dead cells, then increased to 10.9% underwent pre-neutralizing CD40 condition, while pre-blocking both CD40 and Integrin α5β1 concomitantly caused only 1.9% of cell death. RNA sequencing of co-cultured HLFs with activated CD4+ T cells revealed the upregulation of interferon (IFN) and immune response pathways. Elevated IFN-γ levels in the activated T cell media stimulated the JAK1/STAT3 pathway, resulting in increased CD40 expression in HLF. Collectively, CD40 expression in poorly differentiated HCC cells prevents cell death by interacting with CD40L in activated T cells. Targeting CD40 may represent a promising anticancer therapy.