DLC1 inhibits lung adenocarcinoma cell proliferation, migration and invasion via regulating MAPK signaling pathway

Lung adenocarcinoma (LUAD), one of the most common cancers, is a major threat to people's health due to its high mortality, and the survival of most patients suffering LUAD remains poor. This study aimed to explore the mechanism of Deleted in Liver Cancer 1 (DLC1) as a tumor suppressor underlying the occurrence and progression of LUAD. As revealed by bioinformatics analysis and qRT-PCR, DLC1 was significantly down-regulated in LUAD tumor tissue and cells. A series of cellular experiments including CCK-8, wound healing and Transwell assays were performed to detect the effect of DLC1 on the biological function of LUAD cells. It was found that overexpressing DLC1 significantly inhibited LUAD cell proliferative, migratory and invasive abilities, while knockdown of DLC1 promoted these abilities. Gene Set Enrichment Analysis (GSEA) and dual-luciferase assay were used to explore the downstream signaling pathway of DLC1, finding that DLC1 could remarkably inhibit the activity of mitogen-activated protein kinase (MAPK) signaling pathway. Western blot implemented for MAPK signaling pathway-related proteins further identified that DLC1 restrained the activation of MAPK/ERK signaling pathway. Furthermore, rescue experiments suggested that DLC1 inhibited LUAD cell proliferation and invasion by suppressing the MAPK/ERK signaling pathway. Overall, our study discussed the DLC1-dependent mechanism involved in LUAD. We found that the up-regulation of DLC1 may inhibit the malignant progression of LUAD by suppressing MAPK signaling pathway, which supports the view that DLC1 may serve as a molecular target for the targeted therapy of LUAD patients.