DNMT3A triggers tumorigenesis of non-small cell lung cancer through regulation of SLIT2 methylation and SLIT2-mediated macrophage M1/M2 polarization

Increased DNA methylation is prevalent in human cancers and is one of the important characteristics of tumors. This research aims to investigate the molecular mechanisms that involve DNMT3A and DNA methylation modification of SLIT2 in non-small cell lung cancer (NSCLC). Gene expression was examined using Western blot assay, immunohistochemistry and RT-qPCR. Cell viability and motility were measured by CCK-8, colony formation, Transwell and wound healing assays. Macrophage M1/M2 polarization was assessed through a flow cytometry assay. Using ELISA, the secretion levels of inflammatory factors by macrophage M1/M2 polarization were determined. ChIP, qMSP and dual-luciferase reporter assays confirmed the relationship between DNMT3A and SLIT2. High expression of DNMT3A was observed in NSCLC patients, enhancing NSCLC cell viability and metastasis. Mechanically, DNMT3A was identified to target SLIT2. DNMT3A inhibited SLIT2 expression through DNA methylation modification in NSCLC. Further, overexpression of SLIT2 impeded M2 polarization of macrophages in NSCLC. And SLIT2 overexpression hindered NSCLC tumor growth in vivo by affecting macrophage M2 polarization. Finally, DNMT3A was found to promote the progression of NSCLC by downregulating SLIT2. DNMT3A promotes the progression of NSCLC via regulating methylation modification of SLIT2 and SLIT2-mediated macrophage M1/M2 polarization.