IntroductionHepatocellular carcinoma (HCC) represents the third leading cause of cancer mortality worldwide with approximately 40% of patients diagnosed at advanced stages. Immunotherapy and tyrosine-kinase inhibitors sorafenib and lenvatinib represent the first-line treatments in HCC. Despite immunotherapy has revolutionized HCC management, advanced stages are characterized by limited response and early onset of drug-resistance. The identification of biomarkers of treatment response or tumor escape is still an unmet clinical need.AimsThe aims of this study are to investigate miR-22 contribution to HCC tumorigenesis and sorafenib response, and to analyze its role as a biomarker of drug response.Materials and MethodsSerum and tissue miR-22 levels were analyzed by qPCR in HCC patients and DEN-HCC rats. Proliferation and apoptosis assays and live imaging analysis evaluated miR-22 influence on HCC phenotype in vitro. A xenograft mouse model was used to determine the role of miR-22 on HCC tumorigenesis. Functional analysis elucidated the regulation of HIF-1A pathway following miR-22 modulation in different settings.ResultsMiR-22 was downregulated in human and rat HCCs and associated with microvascular invasion, tumor grade, and a worse overall survival. In vitro assays revealed that miR-22 inhibits cell growth in normoxic and hypoxic conditions and blocked HIF-1A pathway in HCC cells. Regarding in vivo tumorigenesis, miR-22 silencing gave rise to bigger and more vascularized tumor masses in xenograft mice. Lower miR-22 tissue levels associated with sorafenib resistance and correlated with apoptotic markers in the rat model while serum levels showed the opposite. In sorafenib-treated patients, a positive correlation between circulating miR-22 levels and days of treatment was observed. In line, lower miR-22 basal levels were detected in non-responder HCCs.ConclusionLow miR-22 levels favor HCC tumorigenesis and associate with a poor prognosis. MiR-22 influences sorafenib sensitivity and deserves attention as a possible biomarker of treatment response.

IntroductionPossible curative options for hepatocellular carcinoma (HCC) are limited to a minority of patients who are diagnosed at an early stage. Immunotherapy and TKIs (sorafenib and lenvatinib) represent the first-line treatments in HCC. Despite immunotherapy has revolutionized HCC treatment, only a minority of patients respond to systemic treatments. The identification of biomarkers of drug response or tumor escape is still an unmet clinical need. MicroRNAs and chemokines play pivotal roles in tumor progression and drug resistance of HCC. We previously reported miR-30e-3p as a candidate for tumor escape in patients undergoing sorafenib treatment.AimsThe aims of this study are to investigate CXCL3 regulation by miR-30e-3p, and to analyze its role in sorafenib resistance, and as a biomarker of tumor escape.Materials and MethodsSerum and tissue miR-30e-3p and CXCL3 levels were analyzed by microarray and qPCR analysis in HCC patients and DEN-HCC rats. Functional analysis was used to assess CXCL3 targeting by miR-30e-3p in HCC cell lines. The contribution of CXLC3 to sorafenib response was evaluated in the DEN-HCC rat model. ELISA assay evaluated serum CXCL3 levels in sorafenib-treated HCC patients.ResultsCXCL3 was upregulated in human and rat HCCs and showed a direct correlation with CXCR2 and a negative one with miR-30e-3p. Functional analyses demonstrated CXCL3 targeting by miR-30e-3p in HCC cell lines, as confirmed by a luciferase reporter assay. Higher CXCL3 tissue levels associated with sorafenib resistance in the HCC rat model. In line, a negative correlation was detected between CXCL3 and apoptotic markers and positive one with tumor size in sorafenib-treated rats. Higher CXCL3 serum levels were observed in non-responder patients at the two-month follow-up.ConclusionCXCL3 is a novel target of miR-30e-3p in HCC and is involved in sorafenib resistance. CXCL3 is a promising circulating biomarker of early tumor escape in sorafenib-treated HCCs.