Expression of CDCA7 Is a Prognostic Biomarker and Potential Therapeutic Target in Non-small Cell Lung Cancer 

Abstract BackgroundCell Division Cycle Associated 7 (CDCA7) was first identified as a direct target gene of c-Myc and dysregulated in various types of human cancer. However, it has limited implication in non-small Cell Lung Cancer (NSCLC). We aimed to explore the critical role of CDCA7 in NSCLC.Methods In this study, we identified CDCA7 upregulation and association with the prognosis of NSCLC by integrating analysis of 3 Gene Expression Omnibus (GEO) databases. Real-time PCR and immunohistochemistry (IHC) were used to determine collected clinical NSCLC samples. Chi-square test was used to examine possible correlations between CDCA7 expression and clinicopathological factors. Univariate and multivariate Cox proportional hazards regression analysis were performed to determine whether CDCA7 is an independent risk factor for overall survival (OS). The effect of CDCA7 expression on proliferation, cell cycle and apoptosis ability of NSCLC cells was detected by cell counting kit-8 (CCK-8) and flow cytometry. CDCA7 stably knocking down cell line was established and Western blotting assay was applied to measure relevant protein expression. Xenograft models were used to examine the role of CDCA7 on tumorigenicity of NSCLC cells.Results Analysis of clinical samples confirmed the CDCA7 high expression in tumor tissues compared with adjacent non-tumor tissues and predicted shorter OS time. COX proportional risk model analysis showed that the expression levels of CDCA7 was independent prognostic factors. We observed that CDCA7 silencing efficiently affect the proliferation, apoptosis and cycle distribution of NSCLC cells in vitro. Further results demonstrated that the expression of CDCA7 in A549/DDP cells was significantly higher than that in A549 cells, CDCA7 silencing efficiently down regulation cisplatin sensitivity in A549/DDP cells. Importantly, the depletion of CDCA7 strongly reduced the tumorigenicity of NSCLC cells in vivo. Furthermore, depletion of CDCA7 expression markedly affected the expression of cell division protein kinase 6 (CDK6) and caspase7 both in vitro and in vivo. In vitro study, we showed that CDCA7 silencing promotes A549 apoptosis via extracellular regulated protein kinases (ERK) pathway.ConclusionHighly expressed CDCA7 plays a crucial role in the pathogenesis of NSCLC and might be a potential prognostic factor and therapeutic target in NSCLC.