Research On The Expression Of TMEM48 In Human Non-small Cell Lung Cancer And Its Promotive Role In Tumor Progression

Lung cancer is one of the most frequently diagnosed lethal malignancy with the highest morbidity and mortality around the world,and non-small cell lung cancer(NSCLC)account for 85% of its pathological types.Though the increasingly improvement of diagnostic and therapeutic techniques and equipments,the therapeutic efficacy of NSCLC proves to be poor and its 5-year overall survival is still 15%~20%.Transmembrane protein 48(TMEM48)as the most conserved membrane nucleoporin(Nup)is a crucial part of Nuclear pore complex(NPC)and play a connecting role of anchoring the NPC to nuclear envelope.Some research have been reported the close relationship between carcinogenesis and dysfunction of NPC result from mutation and abnormal expression of Nups family members,while the correlation of TMEM48 and cancer have never been reported before.Our research would be divided into five parts to explore the TMEM48 gene expression in NSCLC and its promoting role in tumor progression,which could provide a new prognostic and predictive index for NSCLC and provide the development of new personalized targeted therapy drugs based on TMEM48 gene with some theoretical basis.Our project group found the high mRNA expression of TMEM48 in 10 pairs of NSCLCL tissues against corresponding adjacent tissues through high-throughput sequencing technique,and the following analysis with TCGA database further observed that the high mRNA expression of TMEM48 has a strong negative correlation with overall survival of NSCLC patient.Then in the first part we enlarged the number of samples to sixty pairs of NSCLCL tissues and corresponding adjacent tissues to demonstrated the accuracy and authenticity of the results above,and the outcomes suggested patients with higher TMEM48 expression frequently have bigger size of tumor and incidence of lymph nodes metastasis,more advanced pathological stage,shorter disease-free survival and overall survival(P<0.05).In the second part,we successfully constructed and packaged three kinds of TMEM48-shRNA-lentivirus plasmids to produce a stable knock-down effect on TMEM48 for subsequent researches.In the third part,after TMEM48 was silenced through lentivirus-mediated RNA interference(RNAi)in A549 and H1299 NSCLC cells,we found the obviously increased apoptosis and significantly decreased proliferation,adhesion,migration and invasion ability against the valid plasmid virus as controlled group(P<0.01).In forth part,A549 cells treated with lentivirus-mediated TMEM48 RNAi were injected into BALB/c nude mouse for 60 days,then we observed both the volume and weight of tumor were remarkably less than that of controlled group(P<0.01).In the fifth part,we continue to elucidate the potential mechanism of cell phenotype and function in third part,and detect the change of downstream relevant molecule through Real-time PCR and Western blot analysis.Finally,we observed down-regulated expression of cell cycle genes CyclinB1?CDK1 and CDC6,DNA replication genes PCNA and RFC,anti-apoptotic genes Bcl-2,XIAP,and Survivin,and invasion relevant genes MMP-2 and MMP-9,and up-regulated expression of pro-apoptotic gene Bax by TMEM48 knockdown in A549 and H1299 cells.Consequently,our research indicating that TMEM48 probably a early-micrometastasis diagnosis and poor prognostic biomarker for NSCLC patients and it could inhibit cell apoptosis as well as promote proliferation,adhesion,migration and invasion ability of NSCLC cells through interacting with relevant critical genes.