TM4SF5-mediated liver malignancy involves NK cell exhaustion-like phenotypes.

Area of Science:

• Hepatology
• Cancer Biology
• Immunology

Background:

• Aberrant extracellular matrix and immune cell changes in the tumor microenvironment drive liver carcinogenesis.
• Transmembrane 4 L six family member 5 (TM4SF5) is implicated in liver fibrosis and cancer, but its role in immune evasion during carcinogenesis is unclear.

Purpose of the Study:

• To investigate the mechanism by which TM4SF5-mediated signaling contributes to immune evasion during liver carcinogenesis.
• To explore the therapeutic potential of targeting TM4SF5 to restore anti-tumor immunity.

Main Methods:

• Utilized in vitro primary cells and in vivo genetic (TM4SF5-transgenic) and chemical (diethylnitrosamine-induced) mouse models of liver cancer.
• Assessed TM4SF5, pY705STAT3, extracellular matrix components (collagen I, laminin γ2), and natural killer (NK) cell phenotypes.
• Employed the TM4SF5 inhibitor 4'-(p-toluenesulfonylamido)-4-hydroxychalcone (TSAHC) to evaluate its effects.

Main Results:

• TM4SF5 overexpression in mouse models correlated with liver fibrosis, cancer, and elevated pY705STAT3, collagen I, and laminin γ2.
• TM4SF5 inhibition by TSAHC reversed these effects, including blocking NK cell exhaustion phenotypes (reduced number/function).
• TM4SF5 suppressed NK cell cytotoxicity by downregulating stimulatory ligands/receptors (SLAMF6, SLAMF7, MICA/B) and reducing STAT3 signaling.

Conclusions:

• TM4SF5-mediated STAT3 activation contributes to extracellular matrix remodeling and immune suppression, promoting liver disease progression to hepatocellular carcinoma (HCC).
• Targeting TM4SF5 restores NK cell surveillance, reduces tumor burden, and improves survival in preclinical models of liver carcinogenesis.