Ccny, Zfx Tumor Related Gene Function And Mechanism Of Regulating The Proliferation Of Lung Cancer Research

Background:Cyclin Y was a recently identified cell cycle regulatory protein that played animportant role in the regulation of cell cycle and transcription.Thus, Cyclin Y mightplay a critical role in tumor initiation and progression. Recently, studies discovered ahomologous isomer Cyclin X, also known as a new member of cyclin protein family.Researches had demonstrated that Cyclin Y was localized in plasma membrane, whileCyclin X was differently distributed in cytoplasm becase of losing the N-terminalmyristoylation site. However, relations between the two proteins and their effects oncell proliferation are unclear. Hence, the aim of this study was to explore the differentrole of CCNY and CCNX in lung cancer by overexpressing the two proteins innormal cell line and lung cancer cell lines.Methods:Immunoflurescent staining was used to detect the endogenous expression of Cyclin Yand Cyclin X in lung cancer cell lines and HEK293cell line. Eukaryotic expressionvectors including pEGFP-N1/CCNY, pEGFP-N1/CCNX and pEGFP-N1/CCNY(G2A) were constructed and transfected into lung cancer cell lines (H1299, H446)and HEK293cells. The expression and subcellular localization of Cyclin Y andCyclin X were detected by fluorescence microscope, immunoflurescent staining andWestern Blot. The functional role of CCNY and CCNX in lung cancer cells and HEK293cells was evaluated by analysis of cell proliferation.Results:1. Cyclin Y and Cyclin X were abundantly expressed in lung cancer cell lines whileno fluorescence signal was detected in HEK293cells. The expression level of CyclinY and Cyclin X was different in lung cancer cells: both Cyclin Y and Cyclin X wereexpressed in A549cell line, but in H446cell line, Cyclin Y was mainly expressed; In contrast, Cyclin X is major distributed in H1299,95C and95D cell lines. However,Cyclin Y and Cyclin X are co-localizated with PFTK1in all the detected lung cancercells.2. In this study, the eukaryotic expression plasmid pEGFP-N1/CCNY,pEGFP-N1/CCNX and pEGFP-N1/CCNY(G2A) had been successfully constructedand transfected into the HEK239,H1299and H446cell lines. We verified that ectopicexpressed Cyclin Y was distributed in plasma membrane, while Cyclin X and CyclinY (G2A) were differently localizated in cytoplasm and nucleus because of losing theN-terminal myristoylation site.3. Functionally, Cyclin X and Cyclin Y (G2A) which were distributed in cytoplasmand nucleus, instead of Cyclin Y, significantly promoted cell viability.Conclusion:1. Cyclin Y and Cyclin X were highly expressed in lung cancer cells. But theexpression of Cyclin Y and Cyclin X was not detected in HEK293cells. AlthoughCyclin Y and Cyclin X had different distribution in lung cancer cell lines, both ofthem were co-localizated with PFTK1. We speculated that Cyclin Y and Cyclin Xmay play a different role in the development of lung cancer.2. Cyclin X and Cyclin Y(G2A), which losed the plasma membrane localization,played a critical role in cell growth control.Thus, it is possible that Cyclin Y may notinvolved in the regulation of cell cycle, Cyclin X might be the functional form ofCyclin Y.3. Further researches on Cyclin Y, Cyclin X and PFTK1are necessary. It could notonly help elucidate the mechanism of tumorgenesis but also provide a newperspective on the control of cancer. Background:Zinc finger protein, X-linked (ZFX) is a transcription factor encoded by its gene onthe mammalian X chromosome, and functions to control survival and activity of stemcells and lymphocytes. However, little is known about the role of ZFX in thetumorigenesis.Patients and Methods:The function of ZFX in cell proliferation was investigated by the lentivirus-mediatedshort hairpin RNA interference (shRNA) approach in NSCLC cell culture lines. Theexpression profiles of ZFX in49pairs of tumors and corresponding matched adjacentnormal tissues from non-small cell lung cancer (NSCLC) patients were examined byReal-time PCR.Results:The specific knockdown of ZFX by shRNA significantly inhibited cell viability andreduced colony formation of95D cells. And ZFX silencing resulted in cell cyclearrest in G0/G1phase. In addition, ZFX was overexpressed and correlated withlymph node metastasis in samples from49NSCLC patients.Conclusions:We reported for the first time that ZFX may play an important role in cell growthcontrol and cell cycle progression of95D cells.Furthermore, ZFX was overexpressedin samples of NSCLC and ZFX mRNA expression associated with lymph nodemetastasis. Therefore, our findings suggest that ZFX would be a potential target todevelopment of therapies for NSCLC.