Effects Of STEAP1 On The Invasion And Metastasis Of Cervical Cancer

BackgroundCervical cancer is one of the gynecological cancers with the highest incidence in the world.In recent years,studies have shown that its incidence is the fourteenth among cancers and the fourth among female cancers.Four main stages are included in the development of cervical cancer:infection of metaplasia epithelium in the cervical transformation zone,persistent virus infection,progression to cervical precancerous lesions,invasion of the basement membrane of the epithelium,migration and invasion.The most common cervical endothelial lesions are intraepithelial neoplasias,which can lead to precancerous lesions and then progress to cervical cancer.Adenocarcinoma and squamous cell carcinoma account for 25%and 70%of them,respectively.Cervical cancer is easy to infiltrate the surrounding tissues,and it is very easy to recur even after surgery,with a high mortality rate.Moreover,frequent radiotherapy and chemotherapy can also make tumor cells resistant,which may greatly reduces the treatment effect.Therefore,the research is difficult and important about the invasion and metastasis of cervical cancer cells and new effective targets will play a vital role in the prevention and treatment of cervical cancer.STEAP1 is a cell surface biomolecule composed of six transmembrane proteins,which connects intracellular and extracellular circulation and regulates intercellular communication,such as small molecules and ions Na+,Ca2+and K+.STEAP1 is highly expressed in cancer cells,such as gastric cancer,lung cancer,ovarian cancer and Ewing’s sarcoma.The high expression of STEAP1 is related to the metastasis,invasion and recurrence of a variety of malignant tumors.In recent years,Researchers have done a lot of research on STEAP1,and a variety of treatment methods targeting STEAP1 have emerged,such as gene vaccine,antibody and inhibitor.At present,the research on the relationship between STEAP1 and cervical cancer is still blank.The purpose of this study was to further investigate the biological function of STEAP1 and explore the relationship between STEAP1 and cervical cancer,which is particularly important for the treatment of inhibiting invasion and metastasis of cervical cancer and to fully improve the prognosis of patients.Objective1.To detect the expression difference of STEAP1 in normal cervical tissue,CIN cervical tissue,cervical cancer tissue and cells.2.To transfect cervical cancer cells with lentivirus,and then detect whether changes in STEAP1 expression will affect the migration and invasion of cervical cancer cells.3.To explore whether STEAP1 affects the epithelial-mesenchymal transition（EMT）process of cervical cancer.Methods1.Immunohistochemistry was applied to compare the expression of STEAP1 in normal cervical tissues,CIN cervical tissues and cervical cancer tissues.2.RT-qPCR,Western Blotting and Immunocytochemistry were used to detect the expression of STEAP1 in Ca-ski,HeLa,Siha and HT-3 cells.3.In vitro migration and invasion ability of the above four types of cervical cells were detected by Transwell chamber.4.Lentiviral transfection was used to down-regulate the expression of STEAP1 in Ca-ski cells（Ca-ski-shRNA）and up-regulate the expression of STEAP1 in HT-3 cells（HT-3-EX）,to verify the relationship between the migration and invasion ability of cervical cancer cells and STEAP1 expression.5.RT-qPCR and Western Blotting were used to verify the effect of STEAP1 protein and mRNA expression on EMT process of cervical cancer cells.6.The subcutaneous tumorigenesis experiment in nude mice was used to verify the effects of up-regulation and down-regulation of STEAP1 expression on tumor growth ability in vivo..Results1.The expression of STEAP1 in normal cervical tissue and CIN tissue was significantly lower than cervical cancer tissue.2.The expression levels of STEAP1 were Ca-Ski>Siha>Hela>HT-3 in four cervical cancer cells,and the migration and invasion abilities of the four cancer cells were also decreased in turn.The high-invasive cell line Ca-Ski had the highest expression of STEAP1,however the low-invasive cell line HT-3 had the lowest expression.The expression of STEAP1 decreased with the decrease of cell invasion ability.3.The migration and invasion abilities of Ca-Ski-shRNA cells with reduced STEAP1 expression were significantly decreased,while the migration and invasion abilities of HT-3-EX cells with increased STEAP1 expression were significantly enhanced.4.In nude mice,the tumor size of Ca-Ski-shRNA group was significantly smaller than that of Ca-Ski group,and that of HT-3-EX group was significantly larger than that of HT-3 group.5.The expressions of N-cadherin,VIM,snail and slug of Ca-Ski-shRNA cells were significantly decreased,while the expression of E-cadherin was increased,which indicated that down-regulated expression of STEAP1 significantly inhibited the progression of EMT.The expression of N-cadherin,VIM,snail and slug in HT-3-EX cells increased significantly,while the expression of E-cadherin decreased,which showed that the over-expression of STEAP1 promoted EMT of cervical cancer cells.Conclusions1.The expression of STEAP1 in cervical cancer was higher than normal tissue and CIN tissue,and the high expression of STEAP1 was positively correlated with the high invasion ability of cervical cancer cells.2.STEAP1 could affect the abilities for migration and invasion in cervical cancer cells and EMT process.