p62 promotes progression of HCC by inducing M2 macrophage polarization associated with suppression of the TRAF6/NF-κB/NLRP3 signaling pathway

Hepatocellular carcinoma (HCC) ranks as the second leading cause of cancer-related mortality globally. Emerging evidence suggests that the autophagy adaptor protein p62 plays a critical role in promoting HCC progression and modulating macrophage infiltration. However, the relationship between p62 and macrophage polarization, as well as the underlying mechanisms, remains to be elucidated. In this study, we demonstrated that p62 was highly expressed in HCC tissues and correlated with poor overall survival of patients, while a trend toward shorter recurrence-free survival was observed but did not reach statistical significance. Further analysis revealed a positive correlation between high p62 expression and macrophage infiltration, particularly M2-type macrophages. Notably, among patients with elevated p62 levels, individuals with high levels of M2-type macrophage infiltration had the shortest survival. In vitro and in vivo experiments further demonstrated that overexpression of p62 significantly enhanced the proliferation, migration, and invasion of HepG2 cells, as well as promoted the growth of HCC xenografts in nude mice. Mechanistically, overexpression of p62 markedly suppressed the expression of THP-1-derived macrophages M1 type markers CD86 and iNOS, while upregulating the expression of M2 markers CD206 and Arg-1. It was further validated in vivo that overexpression of p62 significantly inhibited the expression of CD86 and M1-associated cytokines IL-6, IL-1β, TNF-α, IFN-γ, CCL5, and CCL9. Conversely, the expression of CD206 and M2-associated cytokines IL-4, IL-10, IL-13, Arg-1, CCL17, and CCL22 was increased. Additionally, overexpression of p62 significantly downregulated the levels of TRAF6, p65, p50, and NLRP3. Collectively, our findings indicate that p62 promotes progression of HCC by inducing M2 macrophage polarization potentially via suppression of the TRAF6/NF-κB/NLRP3 signaling pathway. The p62 protein may serve as an auxiliary diagnostic indicator for the prognosis of HCC patients and represents a potential therapeutic target to reverse M2-type macrophage polarization.