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

Abstract

Hepatocellular carcinoma (HCC) was associated with increased soluble CD40 levels in a previous study. This study aimed to investigate CD40's role in liver tumor progression. CD40 levels were examined in HCC patient tissues and various HCC cell lines, and their interaction with CD4⁺T cells was studied. RNA sequencing analysis was performed to explore the mechanisms of CD40 induction. Poorly differentiated HCC tumor tissues exhibited high membrane-bound CD40 expression, in contrast to nontumor areas. Poorly differentiated HCC cell lines showed high expression of membrane-bound CD40 with low CD40 promoter methylation, which was 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 (CD40 ligand⁺) CD4⁺ T cells increased CD40 levels and showed a modest 3.2% dead cells, then increased to 10.9% underwent preneutralizing CD40 condition, whereas preblocking both CD40 and integrin α5β1 concomitantly caused only 1.9% cell death. RNA sequencing of co-cultured HLFs with activated CD4⁺ T cells revealed the up-regulation of interferon and immune-response pathways. Increased interferon-γ levels in the activated T-cell media stimulated the Janus kinase/signal transducer and activator of transcription 3 pathway, resulting in increased CD40 expression in HLF. Collectively, CD40 expression in poorly differentiated HCC cells prevents cell death by interacting with CD40 ligand in activated T cells. Targeting CD40 may represent a promising anticancer therapy.