The miR-561-5p/CXCL1 Signaling Axis Regulates Pulmonary Metastasis in Hepatocellular Carcinoma Involving CXCR1 Natural Killer Cells Infiltration.

Natural killer (NK) cell can inhibit tumor initiation and regulates metastatic dissemination, acting as key mediators of the innate immune response. Intrinsic factors modulating NK cells infiltration and its anticancer activity remain poorly characterized. We investigated the roles of dysregulation of micro(mi)RNAs and NK cells in progression of hepatocellular carcinoma (HCC). : Small RNA sequencing were used to detect the miRNA profiles of tumor tissues from HCC patients with (n=14) or without (n=13) pulmonary metastasis and HCC cell lines with different pulmonary metastatic potentials. Chemokine expression profiling and bioinformatics were used to detect the downstream target of candidate target. In gain- and loss-of-function assays were used to investigate the role of miRNA in HCC progression. Different subsets of NK cells were isolated and used for chemotaxis and functional assays and . In situ hybridization and immunohistochemical analyses were performed to detect the expression of miRNA in tumor tissues from 242 HCC patients undergoing curative resection from 2010. : Three miRNAs (miR-137, miR-149-5p, and miR-561-5p) were identified to be associated with pulmonary metastasis in patients with HCC. miR-561-5p was most highly overexpressed in metastatic HCC tissues and high-metastatic-potential HCC cell lines. In gain- and loss-of-function assays in a murine model, miR-561-5p promoted tumor growth and spread to the lungs. Yet, miR-561-5p did not appear to affect cellular proliferation and migration . Bioinformatics and chemokine expression profiling identified chemokine (C-X-C motif) ligand 1 (CXCL1) as a potential target of miR-561-5p. Furthermore, miR-561-5p promoted tumorigenesis and metastasis via CXCL1-dependent regulation of CXCR1 NK cell infiltration and function. CXCR1 NK cells demonstrated stronger anti-metastatic activity relative to CXCR1 NK cells. CXCL1 stimulated chemotactic migration and cytotoxicity in CXCR1 NK cells via STAT3 signaling. Blockade of CXCL1, CXCR1, or of pSTAT3 signaling pathways attenuated the antitumor responses. Clinical samples exhibited a negative correlation between miR-561-5p expression and levels of CXCL1 and CXCR1 NK cells. High miR-561-5p abundance, low CXCL1 levels, and low numbers of CXCR1 NK cells were associated with adverse prognosis. : We delineated a miR-561-5p/CX3CL1/NK cell axis that drives HCC metastasis and demonstrated that CXCR1 NK cells serve as potent antitumor therapeutic effectors.