DNMT3b promotes proliferation and invasion by mediating HOPX DNA methylation in lung cancer

DNMT3B is an important DNA methyltransferase related with unfavorable outcomes for cancer patients. DNMT3B can promote the progression of multifarious malignant tumors. Nevertheless, the functional mechanisms through which DNMT3B promotes the malignant progression of lung cancer remain incompletely understood and require further investigation. In this study, we demonstrated that DNMT3B promoted proliferation, migration, and invasion of lung cancer cells <i>in vitro</i> and facilitated tumor growth <i>in vivo</i> in xenograft models. Mechanistically, DNMT3B could downregulate HOPX expression through DNA methylation. Consistently, the DNMT inhibitor (SGI-1027) could significantly upregulate HOPX expression level. High HOPX expression effectively suppressed the proliferation, migration, and invasion of lung cancer cells. In contrast, HOPX knockdown partially recovered the malignant phenotypes of lung cancer cells treated with SGI-1027 or si-DNMT3B. In conclusion, these findings provide a rationale for targeting DNMT3B-mediated HOPX DNA methylation and identify crucial molecular targets for lung cancer therapy.