Knocking Down Rab11-FIP2 Inhibites Migration And Invasion Of Nasopharyngeal Carcinoma Via Rho GTPase Signaling

Background: Nasopharyngeal carcinoma(NPC)is a malignany derived from epithelial tissue of the nasopharynx,which has a unique geographical distribution and complex etiology.Nasopharyngeal carcinoma is mainly endemic in southern China and Southeast Asia.At present,the pathogenesis of nasopharyngeal carcinoma is not completely clear.It is believed that the occurrence of nasopharyngeal carcinoma is related to Epstein-Barr virus(EBV)infection,genetic susceptibility and environmental factors.And the occurrence of nasopharyngeal carcinoma is a complex process of multi-steps and multiple factors interaction.The location of nasopharyngeal carcinoma is greatly concealed,so it is difficult to find it.Therefore,when the patients firstly diagnosed as nasopharyngeal carcinoma,cancer cells have metastasized from primary tumor to cervical lymph node for a growing number of patients.At present,the therapeutic method of nasopharyngeal carcinoma is integrated therapy which radiotherapy is still the main means.Although the 5 years survival rate is greatly improved thanks to the development and application of radiotherapy,but the local recurrence and metastasis to distant organs of nasopharyngeal carcinoma are still the main reasons of treatment failure and patients death.Therefore,it is imminent to explore the mechanism of metastasis and to find the possible therapeutic targets for nasopharyngeal carcinoma.Literatures showed that Rab11 family interacting protein(Rab11-FIPs)are closely related to the metastasis of many tumors,but its specific mechanism has not yet been elucidated.The study of Rab11-FIP2 in nasopharyngeal carcinoma has not been reported.Therefore,this article will study the expression of Rab11-FIP2 in nasopharyngeal carcinoma and explore its biological function and possible molecular mechanism of nasopharyngeal carcinoma.Objective: To explore the expression of Rab11-FIP2 and its effect on the biological behavior in nasopharyngeal carcinoma and its potential molecular mechanism.Methods: 1.We analyzed the transcriptional levels of Rab11-FIP2,Rab11 and MYO5 B in nasopharyngeal carcinoma samples from Sengupta head and neck cancer in oncomine database,and screened out differentially expressed gene from the complex of Rab11-Rab11-FIP2-MYO5 B which involved in endosome recycling.2.The transcriptional and expression of Rab11-FIP2 in nasopharyngeal carcinoma were validated by Real-time RT-PCR,immunohistochemical staining,respectively.3.The expression of Rab11-FIP2 after interfered Rab11-FIP2 was verified by Real-time RT-PCR,Western blot,respectively.4.Knocking down Rab11-FIP2 in NPC cells,and then we investigating the biological behavior of knockdown Rab11-FIP2 in nasopharyngeal carcinoma cells by performing proliferation assay,plate colony formation assay,wound healing and transwell assay in vitro.5.Detecting the expression of Rac and Cdc42 which belongs to Rho signaling pathway,epithelial mesenchymal transition(EMT)related factors,such as vimentin,?-catenin and E-cadherin,and Akt/p Akt by Western blot assay in NPC cells which knocked down Rab11-FIP2 to explore the signal pathway that Rab11-FIP2 affects the metastasis of nasopharyngeal carcinoma cells.Results: 1.The expression level of Rab11-FIP2 is up-regulated in nasopharyngeal carcinoma In the Sengupta Head-Neck Statistics of the oncomine database,the expression of Rab11-FIP2 in nasopharyngeal carcinoma was up-regulated,but there was no significance in the expression of Rab11 and MYO5 B.The transcriptional and expression levels of Rab11-FIP2 in nasopharyngeal carcinoma was also up-regulated.2.Knockdown of Rab11-FIP2 suppressed the migration and invasion of NPC cells In 5-8F and TW03 cell lines,knocking down the Rab11-FIP2 did not affect the proliferation and the colony formation of NPC cells.However,Rab11-FIP2 knockdown inhibited the migration and invasion of NPC cells.3.Knocking down Rab11-FIP2 did not affect EMT and Akt signaling pathway of NPC cells When knocking down Rab11-FIP2,we found that the expression of EMT markers,such as vimentin,?-catenin and E-cadherin,and the Akt/p Akt were no significant changes.It indicated that Rab11-FIP2 was not involved in EMT and the phosphorylation of Akt in NPC.4.Knocking down Rab11-FIP2 inhibited the migration and invasion of NPC cells through the Rho GTPase signaling pathway Rac and Cdc42,which are belong to Rho GTPase signaling pathway were significantly down-regulated in NPC cells with Rab11-FIP2 si RNA knockdown as compared with control si RNA knockdown.It indicated that knocking down Rab11-FIP2 inhibited the migration and invasion of NPC cells through Rac/Cdc42 pathway.Conclusions: 1.The transcriptional and expression levels of Rab11-FIP2 was up-regulated in NPC.2.Knockdown Rab11-FIP2 could inhibit the migration and invasion NPC cells.3.Knocking down Rab11-FIP2 suppressed the metastasis via Rho GTPase signaling pathway in NPC.To sum up,Rab11-FIP2 may be a candidate tumor gene in NPC.