STAT3 Impacts On Tumor Invasion And Metastasis Through Modulating TGF-?/MALAT1/miR30a Axis In HNSCC

Human head and neck squamous cell carcinoma is one of the most prevalent cancers in the world.Its progression developes faster than others and its prognosis is often bad.It is one of the most serious threats to human health.This is associated with the early metastasis and the severe local invasion of the head and neck squamous cell carcinoma.In recent years,although surgery,chemotherapy and radiotherapy have been used in many ways,the survival time of patients with head and neck squamous cell carcinoma had not improved significantly,and the life quality of advanced patients is very poor.Therefore,it is urgent to seek more precise targets to inhibit the metastasis and invasion of the tumor and to improve the therapeutic effect of the squamous cell carcinoma of the head and neck.Objective: MALAT1 is a long-chain noncoding RNA which is highly conserved and has important functions in mammalian evolution.It is involved in the occurrence and development of many kinds of tumors.The purpose of this study is to investigate the expression level of MALAT1 in head and neck squamous cell carcinoma,and whether the high expression of MALAT1 can promote the local invasion and metastasis of tumor,as well as the regulation mechanism of MALAT1.Method:1.Analyzing the expression level of MALAT1 through the TCGA database and the NIH-GEO database.The surgical specimens were collected from the maxillofacial otorhinolaryngology Department of the Tianjin Medical University Cancer Institute Hospital.The specimens were stained with FISH,and the coloring of tumor tissue and adjacent normal tissues were compared.The expression level of mi R-30 a is analyzed by "Pan Cancer" in the TCGA database.2.The SCC15 and SCC25 cell lines in the head and neck squamous cell carcinoma were purchased.The inhibition of MALAT1 expression by transfection of si RNA.Transwell test and scratch assay was for detecting invasion and metastasis of tumor cells.The expression of related protein was detecting by Western blot assay;the expression of gene by q-PCR assay;immunofluorescence assay was used for the changes of cytoskeleton;luciferase reporter gene assay detected combined position;chromatin immunoprecipitation detected the interacting model of gene.3.To establish the orthotopic tumor model of human head and neck squamous cell carcinoma in vivo,and to observe the growth of the tumor in vivo with an IVIS Lumina Imaging System.The weight of mice was weighed regularly,and the size and weight of the tumor and were measured after the mice were sacrificed.Result:1.There were abnormal MALAT1 overexpression in HNSCC specimens,and the expression level of MALAT1 in tumor tissues was significantly higher than that in adjacent normal tissues.2.When the expression of MALAT1 was inhibited,the levels of MMP2 and MMP9 protein were decreased,with increased expression of epithelial marker E-cadherin,and significantly decreased expression of mesenchymal markers N-cadherin,Vimentin and Twist.In the Transwell assay with / without Matrigel,the outside cells were reduced.The cytoskeleton changed obviously,and the pseudopodium disappeared.After promoting the expression of mi R-30 a,the level of MMP2 and MMP9 protein were decreased,the expression of E-cadherin was increased,and the expression of mesenchymal markers N-cadherin,Vimentin and Twist was decreased.The outside cells in the transwell experiment were reduced.The typical structure of the pseudopodium in the cytoskeleton was disappeared.Mi R-30 a can be combined with MALAT1 directly,and MALAT1 can inhibit the expression of mi R-30 a.STAT3 can be directly associated with MALAT1,and there is a significant positive correlation between the expression of the them.The expression of TGF-beta was positively correlated with the expression of STAT3 and MALAT1,and was negatively correlated with the expression of mi R-30 a.3.We can observe the size of tumor by IVIS Lumina Imaging System,and measure the size and weight of tumor after sacrificing mice.We know that tumor growth was inhibited by inhibiting the expression of STAT3 and MALAT1 and promoting the expression of mi R-30 a.Conclusion:1.MALAT1 can promote the invasion and metastasis of cells in squamous carcinoma the head and neck,which is related to the regulation of the EMT process.2.The expression of MALAT1/mi R-30 a is regulated by TGF-beta and STAT3.3.The experimental results of the nude mice in the head and neck squamous cell carcinoma were in agreement with the experimental results in vitro.