Myofibroblast-derived extracellular vesicles facilitate cancer stemness of hepatocellular carcinoma via transferring ITGA5 to tumor cells

Myofibroblasts constitute a significant component of the tumor microenvironment (TME) and play a pivotal role in the progression of hepatocellular carcinoma (HCC). Integrin α5 (ITGA5) is a crucial regulator in myofibroblasts of malignant tumors. Therefore, the potential of ITGA5 as a novel target for the therapeutic strategy of HCC should be investigated. Digital scanning and analysis of the HCC tissue microarray were performed to locate the distribution of ITGA5 and conduct the prognosis analysis. CRISPR Cas9-mediated ITGA5 knockout was performed to establish the ITGA5-KO myofibroblast cell line. Extracellular vesicles (EVs) derived from LX2 were extracted for the treatment of HCC cells. Subsequently, the sphere-forming ability and the stemness markers expression of the treated HCC cells were examined. An orthotopic HCC mouse model with fibrotic injury was constructed to test the outcomes of ITGA5-targeting therapy and its efficacy in the programmed death-ligand 1 (PD-L1) treatment. Co-immunoprecipitation/mass spectrometry and transcriptome data were integrated to delve into the mechanism. The tissue microarray results revealed that ITGA5 was highly enriched in the stromal myofibroblasts of HCC tissues and contributed to enhanced tumor progression and poor prognosis. Notably, ITGA5 transmission via extracellular vesicles (EVs) from myofibroblasts to HCC cells induced the acquisition of cancer stem cell-like properties. Mechanistically, ITGA5 directly bind to YES1, facilitating the activation of YES1 and its downstream pathways, thereby enhancing the stemness of HCC cells. Furthermore, the blockade of ITGA5 impeded tumor progression driven by ITGA5+ myofibroblasts and enhanced the efficacy of treatment with PD-L1 in a mouse model of HCC. Our findings elucidated a novel mechanism by which the EV-mediated transfer of ITGA5 from myofibroblasts to tumor cells augmented HCC stemness. ITGA5-targeting therapy helped prevent the progression of HCC and improved the efficacy of PD-L1 treatment.