Preliminary Study On The Role Of DEPDC1Gene In Nasopharyngeal Carcinoma

Objective:DEPDC1gene is a novel neoplastic related gene, located in1p31.2,with a whole sequence of23Kb, coding two kinds of proteins with93kD and61kD. There were researches showing that DEPDC1gene overexpressed inthe bladder carcinoma, breast carcinoma, adenocarcinoma of lung.Otherwise, DEPDC1expression was hardly detectable in any of24normalhuman tissues except the testis. Through the current several reports, weconsider this gene to be a novel oncogene, related with the cell proliferation,apoptosis, cell cycle, differentiation and so on. However, up to now, theeffect of this gene in the nasopharyngeal carcinoma has not been reported. Inour previous study, we found that DEPDC1gene expressed higher in thenasopharyngeal carcinoma tissues than in the normal nasopharyngeal tissues.On this basis, this article is just to explore the role of DEPDC1gene in thenasopharyngeal carcinoma in order to offer the experimental and theoreticalbasis for the clinical therapy of nasopharyngeal carcinoma.Methods:The effect of DEPDC1depletion on cell proliferation, apoptosis, cellcycle in nasopharyngeal carcinoma cell lines HNE-1and CNE-1:On the basis of principles of siRNA, DEPDC1siRNA was designed and transfectedinto the cell lines HNE-1and CNE-1. The expression of DEPDC1gene wasdetermined in the mRNA and protein levels. Cell morphological changeswere observed by inverted microscope. Cell apoptosis and cell cycle weretested by FCM, while cell proliferation was determined by MTS and tabletcloning.The mechanism of DEPDC1depletion on cell proliferation, apoptosisand celll cycle of HNE-1: The changes of molecules in NF-κB pathway wasdetermined by PCR in cell lines HNE-1. In the same time, the expression ofCCNB1was tested by PCR and Western Blot in HNE-1cells.Results:siRNA of DEPDC1gene could silence the expression of DEPDC1effectively by PCR and Western Blot. Both HNE-1and CNE-1cell linesoccurred significant cell morphological changes. The cell proliferation wassuppressed and cell apoptosis was increased, while cell cycle was retarded inG2/M phase.Several cancer-related genes in the NF-κB pathway were changed inHNE-1cells by PCR. A20gene, an inhibitor of NF-κB activation, wasupregulated and the other several NF-κB target genes such as C-MYC,MMP9，ICAM-1and BCL-2were downregulated. CCNB1related with thecell cycle showed no significant changes in mRNA level, while it showedupregulation in protein level. In summary, our study has found that DEPDC1depletion couldsuppress the cell proliferation, increase apoptosis, retard cell cycle, whichcould be related with the inhibition of NF-κB pathway and the delay ordecrease of CCNB1degeneration. All of these indicates that DEPDC1maypaly a significant role in the development of nasopharyngeal carcinoma andit may be a potential target in the clinical treatment of nasopharyngealcarcinoma.