Exosomal circ-ADRM1 promotes lung adenocarcinoma progression and induces macrophage M2 polarization through regulating MMP14 mRNA and protein.

OBJECTIVE: Lung adenocarcinoma (LUAD) is one of the frequent subtypes of lung cancer, featuring high rates of incidence and mortality. Matrix metalloproteinase 14 (MMP14) is known as a regulator in multiple cancers, whereas its upstream molecular mechanism remains to be investigated. This study aims to reveal the upstream molecular mechanism of MMP14 in LUSC progression. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were conducted to examine the levels of MMP14 mRNA and protein in LUAD cells, respectively. Cell counting kit-8 (CCK-8), transwell assay and wound healing assay were implemented to unveil LUAD cell proliferation, migration and invasion after indicated transfections. Flow cytometry analysis was applied to evaluate macrophage polarization. Mechanism experiments such as western blot, co-immunoprecipitation (Co-IP), RNA pulldown assay, luciferase reporter assay and RNA-binding protein immunoprecipitation (RIP) assay were used to explore relevant molecular mechanisms. RESULTS: MMP14 facilitated LUAD cell proliferation, invasion and migration. MMP14 is the target gene of miR-1287-5p. Circ-ADRM1 upregulates MMP14 expression through sponging miR-1287-5p. Circ-ADRM1 recruits USP12 to impede the ubiquitination of MMP14 protein, thereby enhancing the stability of MMP14 protein. LUAD-derived exosomes induced macrophage M2 polarization by delivering circ-ADRM1. CONCLUSIONS: Circ-ADRM1 promotes LUAD cell proliferation, invasion and migration through upregulating MMP14. Additionally, circ-ADRM1 induces macrophage M2 polarization in an exosome-dependent manner.