Deubiquitinating enzyme JOSD2 affects susceptibility of NSCLC cells to anti-cancer drugs through DNA damage repair.

Abstract

To investigate the effects of deubiquitinating enzyme Josephin domain containing 2 (JOSD2) on susceptibility of non-small cell lung carcinoma (NSCLC) to anti-cancer drugs and its mechanism. The transcriptome expression matrix and clinical data of NSCLC were downloaded from the Gene Expression Omnibus database. Principal component analysis and limma analysis were used to investigate the deubiquitinating enzymes up-regulated in NSCLC tissues. Kaplan-Meier analysis was used to investigate the relationship between the expression of deubiquitinating enzymes and overall survival of NSCLC patients. Gene ontology enrichment and gene set enrichment analysis (GSEA) were used to analyze the activation of signaling pathways in NSCLC patients with high expression of JOSD2. Gene set variation analysis and Pearson correlation analysis were used to investigate the correlation between JOSD2 expression levels and DNA damage response (DDR) pathway. Western blotting was performed to examine the expression levels of JOSD2 and proteins associated with the DDR pathway. Immunofluorescence and quantitative analysis were used to detect the sub-localization of JOSD2. Sulforhodamine B staining was used to examine the sensitivity of JOSD2-knock-down NSCLC cells to DNA damaging drugs. Compared with adjacent tissues, the expression level of JOSD2 was significantly up-regulated in NSCLC tissues (P<0.05); and the expression of JOSD2 was significantly correlated with poor prognosis in NSCLC patients (P<0.05). Compared to tissues with low expression of JOSD2, the DDR-related pathways were significantly activated in NSCLC tissues with high expression of JOSD2 (P<0.05). In addition, the expression of JOSD2 was positively correlated with the activation of DDR-related pathways (P<0.01). Compared with control group, overexpression of JOSD2 significantly promoted the DDR in NSCLC cells. In addition, DNA damage agent significantly increase the nuclear localization of JOSD2, whereas depletion of JOSD2 significantly enhanced the sensitivity of NSCLC cells to DNA damaging agents (P<0.05). Deubiquitinating enzyme JOSD2 regulates the malignant progression of NSCLC by promoting DNA damage repair pathway, and depletion of JOSD2 significantly enhances the sensitivity of NSCLC cells to DNA damage agents.