The Mechanism That USP14 Regulates C-Met To Promote Invasion And Metastasis In NSCLC

Background: Metastasis is a major cause of cancer-related death in non-small cell lung cancer(NSCLC).Studies have shown that gene amplification(high protein expression)or mutations of multiple oncogenes are involved in the regulation of invasion and metastasis of NSCLC,including c-Met,EGFR and KRAS.This study found that c-Met was highly expressed in NSCLC cells with potent invasion and metastasis ability,but the mechanism of c-Met upregulation was unknown.We found that the deubiquitination enzyme USP14 silence significantly downregulated c-Met protein expression by sh RNA library screening,suggesting that USP14 may be an important regulatory molecule for the c-Met protein and promote invasion and metastasis of NSCLC.Methods: Western blot was used to detect USP14 and c-Met expression in NSCLC cell lines.We constructed USP14 knockdown stable cell lines by lentivirus infection in non-small cell lung cancer cells A549 and H1299(A549 sh USP14,H1299 sh USP14).Western Blot was used to detect the expression of USP14 and c-Met protein in A549 sh USP14 and H1299 sh USP14 stable cells.USP14 si RNA transfection was performed to examine the protein expression levels of USP14 and c-Met in A549 and H1299.The regulatory mechanism between USP14 and c-Met was investigated by Co-immunoprecipitation(Co-IP)assay.We performed in vitro transwell invasion assay,cell scratch assay,and USP14 inhibitor treatment to determine the function of USP14 and c-Met in the invasion and metastasis of NSCLC.The in vivo metastasis assay was performed to further verify that USP14 silence suppressed the invasion and metastasis of NSCLC cells.Results:(1)USP14 and c-Met were overexpressed in highly metastatic NSCLC cell lines;(2)USP14 regulated c-Met via its deubiquitination activity;(3)USP14 silence suppressed the invasion and metastasis of NSCLC;(4)USP14 silence inhibited the metastasis of A549 cells in vivo.Conclusion: The deubiquitination enzyme USP14 promotes invasion and metastasis of NSCLC by regulating c-Met,and USP14 could be a potential therapeutic target to suppress invasion and metastasis of NSCLC.