Expression Of CCNE1 And Preliminary Study On Its Function And Molecular Mechanisms In Nasopharyngeal Carcinoma

Background:Nasopharyngeal carcinoma(NPC)is an especially prevalent malignant tumor in southern China and Southeast Asia.The pathogenesis underlying NPC is related to heredity(genetic susceptibility),Epstein-Barr virus(EBV)infection,environmental factors,dietary habits,and various tumorigenic factors.Most NPC patients present with more advanced disease,including local invasion and early distant metastases,thus leading to a poor prognosis.Therefore,there is an urgent need to investigate the molecular events associated with NPC initiation,progression,and prognosis,which may facilitate an earlier diagnosis and prognostication,as well as implementing novel therapeutic strategies.CCNE1 is expressed in theGl-S phase of the cell cycle by combining and activating cyclin-dependent kinase 2(CDK2)to adjust mammalian cell division during the G1-S phase transition.Substrate phosphorylation of the CCNE1-CDK2 complex plays an important role in triggering the synchronization of DNA replication,centrosome replication and regulation,chromosome refactoring,and biosynthesis of histones.Increased expression of CCNE1 is associated with disease progression in various malignancies and is associated clinically with worse outcomes and a poor prognosis in patients with breast,ovarian,bladder,endometrial,and colorectal cancers.Some reports identified that CCNE1 triggers drug resistance transition in breast cancer and promotes epithelial-mesenchymal transition in gastric cancer.Some people verified CCNE1 increases cell proliferation in esophageal carcinoma.Here we first explore the role of CCNE1 in nasopharyngeal carcinoma.Objection:1.To analyze the expression and influence of CCNE1 on clinical features of NPC patients.2.To study the biological function of CCNE1 in NPC.3.To figure out the specific mechanism which CCNE1 modulates in NPC.Methods:1.To analyze the expression and influence of CCNE1 on clinical features of NPC patients..(1)By ISH and IHC,we tested expression of CCNE1 in NPC tissues.(2)Analyze prognostic value of CCNE1 expression for NPC.(3)Analyze the other clinical features of CCNE1.2.To study the biological function of CCNE1 in NPC.(1)To test the biolagical functions of CCNE1 in vitro,we infected nasopharyngeal carcinoma cell lines HONE1 and SUNE1 with shRNA lentivirus containing CCNE1 sequence,establised HONE1-shCCNE1 and SUNE1-shCCNE1 stable cell lines.Quantitative real-time PCR(RT qPCR)and Western blot confirmed the expression of CCNE1 in these lines.(2)By MTT,Colony formation,Edu,Transwell and Boyden assays,we explore the influence of CCNE1 on cell proliferation,invasion and migration.(3)To investigate whether the effects of CCNE1 translated in vivo,we subcutaneously injected cells into nude nuce and proceeded intrahepatics assay.(4)To further validated the function of CCNE1 we transfected HONEl and SUNE1 with lentiviral vector overexpressing CCNE1 to finish such similar experiments.3.To figure out the specific mechanism which CCNE1 modulates in NPC.Using Western Blot,we examined levels of cell cycle and EMT related proteins,furkher figured out the specific signaling.Results:1.In NPC,CCNE1 has a higher nuclear expression and the patients with NPC exhibiting high expression of nuclear CCNE1 had a poorer total survival.2.CCNE1 promotes proliferation,invasion,migration,and intrahepatic metastasis of NPC cells in vitro and in vivo.3.CCNE1 activates PI3K/AKT pathway and its downstream cell cycle and EMT related factors.Conclusions:Acting as a potential tumor-promoting marker,CCNE1 activates the PI3K/AKT axis to promote proliferation,invasion and migration of nasopharyngeal carcinoma cell lines.