Desmoglein 2 And Pyrroline-5-Carboxylate Reductase 1 Regulate The Proliferation And Apoptosis In Non-Small Cell Lung Cancer

IntroductionLung cancer is the leading cause of cancer deaths worldwide and non-small cell lung cancer accounts for 85%of all lung cancer cases.Therefore,further researches into the molecular mechanisms underlying tumorigenesis are needed for early diagnosis and more efficient treatment of NSCLC.With the continuous development of bioinformatics,patterns of cancer research have changed dramatically.The development of DNA microarray technology led to an explosion of oncogenomic analysis information.However,the majority of such data are not easily accessible or comparable.In recent years,several important analytic approaches have been applied to microarray analysis,such as the Cancer Genome Atlas(TCGA)and Cancer Genomics Hub(CGHub).Oncomine is a cancer microarray database and web-based data-mining platform,which consists of multiple analysis methods including differential expression analysis,co-expression analysis,meta-analysis,cancer outlier profile analysis(COPA)and so on.After screening the differential-expressed genes in NSCLC with Oncomine database which have not been reported,we chose two genes desmoglein 2(Dsg2)and pyrroline5-carboxylate reductase 1(PYCR1)to further investigate their expression pattern in NSCLC tissues and their effects on NSCLC cell proliferation and apoptosis.This study may further our understanding of tumorigenesis of NSCLC and provide a promising target for diagnosis and treatment.Part ? Desmoglein 2 Regulates Cell Proliferation in Non-Small Cell Lung Cancer Aim:Desmogleins belong to the cadherin superfamily and play a very important role in tumorigenesis by mediating adhesion as well as regulating pathways of proliferation and differentiation.Dsg2 is one of their members and it has been reported to be overexpressed in some malignant skin carcinomas and promote cell proliferation in human colon cancer cells.The objective of this study is to investigate the correlation between Dsg2 expression and NSCLC as well as explore the effects on cell proliferation of Dsg2 and underlying molecular mechanisms both in vivo and in vitro.Methods and materials:1.The expression of Dsg2 was detected by western blot and qPCR in fresh frozen normal and tumor tissues as well as immunohistochemical staining of pathological specimens of NSCLC patients.And then the association between the Dsg2 expression and clinicopathological features together with prognosis of NSCLC were analyzed.2.After knockdown of Dsg2,cell proliferation assays,EdU incorporation assay,clone formation assay,flow cytometry analysis for cell cycle and apoptosis were performed.Western blot assays were used to investigate the underlying targets of Dsg2 in NSCLC.3.Nude mouse model were performed for tumor formation assay.Weight and size of the subcutaneous tumors were recorded,and Dsg2 and Ki-67 expression were evaluated by IHC staining.Results:1.Dsg2 was overexpressed in tumor tissues of NSCLC compared to adjacent normal tissues.Dsg2 expression level was related to tumor size in NSCLC.2.After knockdown of Dsg2 by siRNA,cell proliferation was significantly inhibited and cell cycle was arrested,while apoptosis was not affected in NSCLC cells.3.The silence of Dsg2 down-regulated the expression of cell cycle control regulator p27 and CDK2.4.Dsg2 knockdown suppressed NSCLC tumor growth in vivo.Conclusion:Our findings indicated the important role of Dsg2 in the proliferation of NSCLC,which may be a potential target for treatment in NSCLC.Part ? Pyrroline-5-Carboxylate Reductase 1(PYCR1)Promotes Proliferation and Inhibits Apoptosis in Non-Small Cell Lung CancerAim:Disordered tumor cell metabolism plays a key role in the process of tumorigenesis.Proline metabolism is critically important for tumor cells and Pyrroline-5-carboxylate reductase 1(PYCR1),a key enzyme of proline biosynthesis,was reported to be overexpressed in prostate cancer and promote tumor cell growth in breast cancer.In the current study,we investigated the relationship between PYCR1 and non-small cell lung cancer(NSCLC).Methods and materials:1.The expression of PYCR1 was detected by western blot and qPCR in fresh frozen normal and tumor tissues as well as immunohistochemical staining of pathological specimens of NSCLC patients.And then the association between the PYCR1 expression and clinicopathological features together with prognosis of NSCLC were analyzed.2.After knockdown of PYCR1,cell proliferation assays,EdU incorporation assay,clone formation assay,flow cytometry analysis for cell cycle and apoptosis were performed.Western blot assays were used to investigate the underlying targets of PYCR1 in NSCLC.Results:1.PYCR1 was overexpressed in tumor tissues of NSCLC compared to adjacent normal tissues.High PYCR1 expression was related to poor prognosis of NSCLC patients.2.After knockdown of PYCR1 by siRNA,cell proliferation was significantly inhibited and cell cycle was arrested,while apoptosis was increased in SPC-A1 and H1703 cells.3.The silence of PYCR1 down-regulated the expression of cell cycle control regulator cyclin D1,regulator of the mitochondrial apoptotic pathway B-cell lymphoma-2(Bcl2)and Bcl-xl.Conclusion:Our findings indicate the important role of PYCR1 in the proliferation and apoptosis of NSCLC and identified PYCR1 as a poor prognostic biomarker in NSCLC.