EZH2 regulates tumor-associated macrophages by the KDM6A-mediated inflammatory response in HPV16-positive cervical cancer

Abstract

High-risk HPV subtypes impact the immune response in cervical cancer. Tumor-associated macrophages (TAMs) are well known to contribute to tumor development by regulating the immune response. This study aimed to analyze the mechanism of TAMs by the enhancer of zeste homolog 2 (EZH2) in HPV16⁺ cervical cancer. The HPV16⁺ cervical cancer cells, SiHa and CaSki, were treated with increasing concentrations of EZH2 inhibitor EPZ6438 (5, 10, 20, 40, 80 μM) for 24 h. The KDM6A expression is suppressed in a concentration-dependent manner when EZH2 activity is inhibited. Then, the cancer cells were transfected with pcDNA-control or pcDNA-KDM6A, and treated with the IC₅₀ of EPZ6438. The cell viability, levels of IL-6 and CXCL1, and p-Akt(s473)/Akt proteins were measured. The PMA-treated THP-1 cells were induced into M2 macrophages by IL-4 and IL-13. The M2 macrophages were cocultured with the conditioned cancer cells to observe the M2 polarization. In vivo experiments, the effects of EZH2 inhibition on tumor growth were investigated in nude mice. EZH2 inhibition suppressed the cell viability and inflammatory response by suppressing KDM6A in HPV16⁺ cervical cancer cells. KDM6A overexpression suppressed the effects of EZH2 inhibition on cell viability and inflammatory response. EZH2 inhibition in cancer cells suppressed the M2 macrophages, and its mechanism was related to the KDM6A-mediated inflammatory response. In nude mice models, EZH2 inhibition effectively reduced tumor growth by regulating KDM6A. EZH2 regulated the KDM6A-mediated inflammatory response, thus affecting the polarization of M2 macrophages, leading to tumor growth in HPV16⁺ cervical cancer. This study provided an insight into the immune modulation of EZH2 in HPV16⁺ cervical cancer.

Keywords: Cervical cancer; KDM6A; Tumor-associated macrophages.