Background The role of dysfunction of expression is downregulated in lung cancer tissues and that overexpression inhibits the proliferation of non-small-cell lung cancer cells. suppressor gene and a novel candidate therapeutic target in lung cancer. result in primary autosomal recessive microcephaly characterized by a significant reduction in brain size, clinical cortical dysplasia, and mental retardation.7,8 encodes a centrosomal protein containing three BRCA1 carboxy-terminal (BRCT) domains. BRCA1 belongs to the BRCT family of proteins that are involved in DNA repair.9,10 In addition, MCPH1 is associated with the cell damage response, apoptosis, and cell-cycle regulation. MCPH1 acts as a tumor suppressor in a variety of cancer cells.11 In humans, is located on chromosome 8p23.1, where loss of chromosomal region is very common in several malignancies such as for example breast and prostate cancer. In fact, previous research demonstrated that MCPH1 is downregulated in a variety of cancer cells, including cervical cancer, breast cancer, and prostate cancer.8,12 Moreover, overexpression of MCPH1 can inhibit the epithelialCmesenchymal transition (EMT) of cervical cancer cells.13 In addition, our previous studies revealed that MCPH1 is downregulated in lung cancer tissues, and it is also involved in the pathogenesis of lung cancer.14,15 Therefore, we hypothesized that the absence or low-level expression of MCPH1 may play an important role in the initiation and progression of lung cancer. In this study, we first evaluated relapse-free survival of patients with lung cancer and found that patients with high-level MCPH1 expression had significantly longer relapse-free survival than those Odanacatib inhibitor with low-level MCPH1 expression. Next, we studied the biological effects of MCPH1 in a lung cancer cell line and its possible mechanism. Our findings revealed that MCPH1 overexpression inhibits lung cancer cell migration and invasion by blocking Mdm2-mediated ubiquitination of p53. Materials and methods Survival analysis Odanacatib inhibitor Expression profiling microarray data for human lung cancer clinical specimens were collected from the National Center for Biotechnology Information Gene Expression Omnibus (GEO, http://www.ncbi.nlm.nih.gov/geo/). Relative expression for two microarray datasets, namely, “type”:”entrez-geo”,”attrs”:”text”:”GSE8894″,”term_id”:”8894″GSE8894 and “type”:”entrez-geo”,”attrs”:”text”:”GSE31210″,”term_id”:”31210″GSE31210, was assessed with the GEO2R interface (http://www.ncbi.nlm.nih.gov/geo/geo2r/). Survival analysis for non-small-cell lung cancer (NSCLC) patients with different MCPH1 expression levels was performed using the KM plotter database. The prognostic value of MCPH1 was assessed by splitting the patient samples into two groups according to median expression. The survival rate was analyzed with SPSS 17.0 software (IBM Corp., Armonk, NY, USA). Ultimately, 138 patients (in “type”:”entrez-geo”,”attrs”:”text”:”GSE8894″,”term_id”:”8894″GSE8894) and 204 patients (in “type”:”entrez-geo”,”attrs”:”text”:”GSE31210″,”term_id”:”31210″GSE31210) were analyzed. This study was approved by the Ethics Committee of Chongqing Medical University. Written informed consent was waived by the Ethics Committee due to data being de-identified and anonymous. Cell culture and transfection The A549 cell lines were purchased from Cell Bank, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai. A549 human NSCLC cells were Odanacatib inhibitor cultured in DMEM (Thermo Fisher Scientific, Waltham, MA, USA) supplemented with 10% heat-inactivated FBS (Thermo Fisher Scientific), penicillin (50 U/mL), and streptomycin (50 g/mL; Thermo Fisher Scientific). Cells were maintained MAP2K2 at 37C in 5% CO2 moist air. The constructed pcDNA3.1(C) MCPH1 plasmid was used for cell transfection.15 The same number of cells was plated in 24-well and 6-well plates and grown to 80% confluency. Cells in the 24-well plates were transfected with 0.5 g pcDNA3.1(C)MCPH1 or empty vector. Cells in the 6-well plates were transfected with 1.0 g pcDNA3.1(C)MCPH1 or empty vector. The specified Odanacatib inhibitor amounts of vectors were combined in Opti-MEM? medium (Thermo Fisher Scientific) with Lipofectamine 2000. The solution was incubated for 30 min at room temperature and then added to the cultured cells. The medium was changed to DMEM with 10% FBS after 4.