KIF15 Accelerated The Progression Of Nasopharyngeal Carcinoma And Predict Poor Prognosis

Background Nasopharyngeal carcinoma(NPC)is a common tumor in head and neck and is prevailing in China.Although treatment methods continue to improve,the prognosis of advanced patients is still unsatisfactory.Kinesin family member 15(KIF15)is a kind of protein,which regulates the process of cell mitosis and plays an important role in several types of human cancers.Currently,KIF15 has been less studied in nasopharyngeal carcinoma,and its biological function and mechanism of action are still unclear.This study aimed to clarify the expression and clinical significance of KIF15 in nasopharyngeal carcinoma tissues and to explore its role in the biological effects of nasopharyngeal carcinoma.Methods Using bioinformatics technology and immunohistochemical detection of nasopharyngeal carcinoma tissue microarray,we evaluated the differences of KIF15 expression in nasopharyngeal mucosa,nasopharyngeal carcinoma tissues and paraneoplastic tissues at the mRNA and protein levels.We analyzed the relationship between its expression level and clinical stage and prognosis of nasopharyngeal carcinoma patients.BR-V108 lentiviral vector was used to transfect 5-8F and CNE-2Z cells.q-PCR and western blot assays were employed to verify the transfection efficiency and establish stable transfected cell lines.CCK-8 and Clone formation assays were utilized to examine the effect of KIF15 expression levels on the proliferative capacity of nasopharyngeal carcinoma cells.Flow cytometry was performed to detect the effect of KIF15 on apoptosis and cycle distribution of nasopharyngeal carcinoma cells.Scratch assay,Transwell migration assay and invasion assay were applied to detect the effect of KIF15 expression on the migration and invasion ability of nasopharyngeal carcinoma cells in vitro.Western blot assay was used to examine the effect of KIF15 on the expression of epithelial-mesenchymal-transition(EMT)associated protein and matrix metalloproteinase protein(MMP)in nasopharyngeal carcinoma cells in vivo.By a tail vein injection metastasis model in nude mice,we further assessed the effect of KIF15 expression on the metastatic ability of nasopharyngeal carcinoma in vivo.We explored the signaling pathways that KIF15 may impact and the potential mechanisms of action by protein blotting analysis.Finally,we validated the rescue effect of specific pathway inhibitors by cell phenotyping experiments.Results At the level of mRNA and protein expression,KIF15 was expressed at such a higher level in nasopharyngeal carcinoma tissues than in paraneoplastic and nasopharyngeal mucosal tissues.KIF15 protein expression was mainly localized in the cytoplasm,and the expression level of KIF15 was closely related to the clinical stage and tumor recurrence of nasopharyngeal carcinoma patients,and high expression of KIF15 protein was found to be an independent risk factor affecting the prognosis of nasopharyngeal carcinoma patients.KIF15 was relatively highly expressed in nasopharyngeal carcinoma 5-8F and CNE-2Z cells,and both were selected to construct stable transfected cell lines.Knockdown of KIF15 expression inhibited cell proliferation,led to cell cycle G2 phase arrest and promoted apoptosis,and western blot assays also revealed changes in the expression levels of various proteins related to cell cycle and apoptosis.Subcutaneous tumorigenic assays showed that downregulation of KIF15 inhibited the growth of NPC in vivo.Knockdown of KIF15 significantly inhibited the migration and invasive ability of nasopharyngeal carcinoma cells in vitro,and inhibited lung and liver metastasis of cancer cells in nude mice.KIF15 expression levels were also closely related to EMT-related markers and MMP9 expression.After KIF15 knockdown,nasopharyngeal carcinoma cells were found to inhibit invasion and metastasis by upregulating E-cadherin expression and downregulating N-cadherin,Vimentin and MMP9 expression.Similarly,the expression of P38,p-P38,and p-P53 was significantly upregulated after KIF15 knockdown,while the expression of PI3K,AKT,p-AKT,ERK,and P53 did not show significant changes or the expression changes of the two cells were inconsistent,suggesting that KIF15 may achieve its biological effects by inhibiting the MAPK pathway and reducing the phosphorylation of P53.In the final inhibitor response assay,we also observed enhanced proliferation of nasopharyngeal carcinoma cells,a decrease in the proportion of apoptotic cells and a significant inhibition of p53 phosphorylation levels after the addition of the P53 inhibitor Pifithrin-α.This biological effect may be achieved by eliminating P53-mediated cytotoxic apoptosis.Conclusions KIF15 was highly expressed in nasopharyngeal carcinoma tissues,closely correlated with TNM stage and recurrence,and was a risk factor for patient prognosis.kIF15 enhanced the proliferation of nasopharyngeal carcinoma cells in vitro and in vivo,while inhibition of kIF15 expression increased apoptosis and led to cell cycle G2 phase arrest.KIF15 induced EMT in nasopharyngeal carcinoma cells,promoted cell invasion and metastasis,and it may regulate the progression of nasopharyngeal carcinoma by activating MAPK/P53 signaling pathway.It can be used as a new prognostic indicator as well as a potential drug target for the treatment of NPC.