Cancer-associated fibroblast-mediated cellular crosstalk supports hepatocellular carcinoma progression.

BACKGROUND & AIMS Carcinoma-associated fibroblasts (CAFs) are key players in multicellular, stromal-dependent alterations leading to HCC pathogenesis. However, the intricate crosstalk between CAFs and other components in the tumor microenvironment (TME) remains unclear. This study aimed to investigate the novel cellular crosstalk among CAFs, tumor cells, and tumor-associated neutrophils (TANs) during different stages of HCC pathogenesis. APPROACH & RESULTS In the HCC-TME, CAF-derived cardiotrophin-like cytokine factor 1 (CLCF1) increased CXCL6 and TGF-β secretion in tumor cells, which subsequently promoted tumor cell stemness in an autocrine manner and TAN infiltration and polarization in a paracrine manner. Moreover, CXCL6 and TGF-β secreted by HCC cells activated ERK1/2 signaling of CAFs to produce more CLCF1, thus forming a positive feedback loop to accelerate HCC progression. Inhibition of ERK1/2 or CLCF1/ciliary neurotrophic factor receptor (CNTFR) signaling efficiently impaired CLCF1-mediated crosstalk among CAFs, tumor cells, and TANs both in vitro and in vivo. In clinical samples, upregulation of the CLCF1-CXCL6/TGF-β axis exhibited a marked correlation with increased cancer stem cells, "N2"-polarized TANs, tumor stage, and poor prognosis. CONCLUSIONS This study reveals a novel cytokine-mediated cellular crosstalk and clinical network involving the CLCF1-CXCL6/TGF-β axis, which regulates the positive feedback loop among CAFs, tumor stemness, and TANs, HCC progression, and patient prognosis. These results may support the CLCF1 cascade as a potential prognostic biomarker and suggest that selective blockade of CLCF1/CNTFR or ERK1/2 signaling could provide an effective therapeutic target for HCC patients.