Expression And Significance Of Notch1 And Snail Genes In Oral Squamous Cell Carcinoma

Background and objectives:Oral cancer is one of the major cancer in the world,which seriously threatening human health.Oral Squamous Cell Carcinoma（OSCC）is one of the most common malignant tumors in the oral and maxillofacial region,accounting for about 90%of head and neck cancer.Among them,malignancy accounts for 2%-4%.Although the local control rate of tumors is significantly increased,the 5-year survival rate of oral cancer patients is still only 50%,and the main reason for poor prognosis is that it has strong invasive ability and distant metastasis ability^[1].Metastatic spread is triggered by reactivation of embryo development programs which called epithelial-mesenchymal transition（EMT）.The transcription factor Snail is the core driving factor of EMT to promote EMT and boost invasion and metastasis.The purpose of our experiment is to better understand the post-translational regulation of Snail,and detect the expression in oral squamous cell carcinoma like Notch 1,Snail,E-cadherin and FBXO11 genes.Methods:（1）36 cases of oral squamous cell carcinoma and 12 cases of adjacent tissues were surgical resection specimen by the First Affiliated Hospital of Hainan Medical College,which confirmed as the oral squamous cell carcinoma by pathological examination after surgery.The positive rate of Notch 1、Snail、E-cadherin and FBXO11 proteins was detected by immunohistochemical staining.The mRNA expression levels of Notch 1,Snail,E-cadherin and FBXO11 were detected by q RT-PCR.Western-blot detection was performed protein expression levels of Notch 1,Snail,E-cadherin,and FBXO11 genes.（2）Construction of carrying Luciferase-bearing fluorescent vector of the Snail overexpression,Snail-silenced and the blank negative control group Cal27 cell byRNA interference technology and overexpression vector construction technology.Transfection into the oral squamous cell carcinoma Cal27 cell to form a stable cell line,tail vein injection,Three mouse models of groups:overexpression,silence,and control.Regular biopsy examination transfer and the tumor successfully transferred,executed.Pathological HE staining was performed on lung tissue,liver tissue and distant metastases.Results:（1）The expression of mRNA and protein of Snail,Notch 1,FBXO11 and E-cadherin genes was consistent in the tissues and adjacent tissues of oral squamous cell carcinoma in collected human tissue samples.The correlation was significantly correlated with lymph node metastasis and clinical stage（P<0.05）,but not with age and tumor size（P>0.05）.The expression levels of Snail and Notch 1 mRNA and protein were significantly higher in oral squamous cell carcinoma than in adjacent tissues（P<0.05）.The mRNA and protein expression levels of E-cadherin and FBXO11were significantly higher in adjacent tissues than in cancer tissues（P<0.05）.（2）Construct Snail stable cell lines of overexpression,silencing and control group.Construct the tumor model of the mouse,observing in time.After 8 weeks,the Snail overexpression metastasis rate was the highest in the test mouse model,followed by the control group,and the Snail silencing inhibition group had the lowest tumor metastasis rate.Conclusions:（1）The expression levels of Notch 1 and Snail mRNA and protein were significantly higher in oral squamous cell carcinoma than in adjacent tissues,while the expression levels of E-cadherin and FBXO11 mRNA and protein were significantly higher in oral tissues than in oral tissues.mRNA and protein expression were associated with lymph node metastasis and clinical stage,independent of age and tumor size.（2）In vivo,Snail is a tumor-promoting gene,and Snail overexpression can promote tumor metastasis.