The Mechanism Of Integrin αvβ6 In PTC Invasion

BackgroundThyroid carcinoma is one of the most common endocrine tumors of the head and neck,about 95% of endocrine tumors.Thyroid papillary carcinoma(PTC)is the most common pathological types of thyroid cancer,accounting for about 80-85% of thyroid cancer.This tumor is an epidermal malignancy of the thyroid gland,which can occur at any age,but is more common in young women.Although the overall prognosis of PTC is acceptable,PTC patients with strong invasion and metastasis often have poor prognosis.In recent years,with the continuous development of imaging technology,the incidence of PTC has been increasing.Therefore,biological markers closely related to PTC invasion and metastasis were explored and targeted intervention was performed.This study is of great significance for evaluating the invasion and migration potential of PTC and improving the prognosis of PTC patients.Integrin belongs to members of the family of cell adhesion molecules.A transmembrane glycoprotein receptor that is noncovalently bound by α and β subunits.It is so far found only expressed in malignant tumor of epithelial cells containing β 6 integrin subunit.It not only can the mutual adhesion mediated between cells and between cells and extracellular matrix(ECM)of bidirectional transmission signal,but also with a variety of ligands combined with each other,and promote the secretion of growth factors,influencing the formation of blood vessels in tumor tissues,etc..At the same time,integrin β6 can be involved in multiple signaling pathways and play an important role in tumor development and invasion.In recent years,the research on β6 specific antagonists has been increasing,and the RNA interference and antisense oligonucleotide technology targeting integrin β 6 have achieved good anti-tumor effects in a variety of tumor animal models.Therefore,the research of β6 in tumor and the treatment targeting it will become a hot spot in the related research field.Matrix metalloproteinases(MMPs)are named for their need of metal ions such as Zn2+ as cofactors.MMPs can clear the way for the invasion of tumor cells by degrading various collagen components in ECM cells.At present,the members of the family of MMPs family has identified 26,total MMP-9 can degrade gelatin and is seen by some as Ⅳ type protein and MMPs family play a role in tumor cells of the important members of the family.Previous studies have shown that the expression of MMP-9 in tumor cells is significantly higher than that in para-cancer tissues,and excessively high expression of MMP-9 may be closely related to lymph node metastasis.In order to clarify the expression and related mechanism of integrin β6 in PTC,and to provide theoretical support for its use as a specific targeted molecule.This study was conducted from the following three parts:Part Ⅰ EXPRESSION OF INTEGRIN β6 IN PTC AND ITS CLINICOPATHOLOGICAL SIGNIFICANCE OBJECTIVEExpression of integrin β6 in PTC tissues and corresponding normal tissues,with lymph node metastasis(LNM)and without LNM was determined.The correlation between the expression of integrin β6 and various clinicopathological parameters was analyzed,so as to clarify the expression and clinical significance of integrin β6 in PTC.MethodsOn the basis of informed consent of patients or their families,immunohistochemistry(IHC)was used to stain the collected pathological sections,and pathological experts were invited to score the immunohistochemical results.The chi-square test was used to analyze the relationship between the expression of integrin β6 and various clinicopathological parameters.ResultsA total of 76 PTC tissue samples and corresponding para-cancer tissue samples werecollected in this study.IHC results showed that the expression of integrinβ6 in PTC was significantly higher than that in normal tissues,and the expression level of integrin β6 with LNM was significantly higher than that without LNM.The expression of β6 was closely related to the depth of tumor invasion.Conclusion and significanceThe expression of integrin β6 in tumor tissues was significantly up-regulated,which was closely related to the depth of tumor invasion and lymph node metastasis,suggesting that integrin β6 could have an important influence on tumor invasion and metastasis.Integrin β6 is expected to be a potential IHC marker and predict the malignant potential of PTC tissues.Part Ⅱ EFFECT OF INTEGRIN β6 ON MALIGNANT BIOLOGICAL BEHAVIOR OF PTC CELLS OBJECTIVETo investigate the expression of integrin β6 m RNA and protein levels in TPC-1 and BCPAP cells,to explore the effect of integrin β6 on the proliferation and invasion of PTC cells.Methods1.Expressions of integrin β6 in TPC-1 and B-CPAP of two PTC cells were detected by Real-time PCR and Western-Blot at m RNA and protein levels.2.β6-si RNA and β6 overexpressed plasmids were transfected in TPC-1 and B-CPAP cells respectively,and interference and overexpression effects were detected by Real-time PCR and Western-Blot.3.After intervention of integrin β6 expression,cell proliferation was detected using CCK8,and changes in cell invasion ability were investigated using Transwell assay.ResultsThe expression of integrin β6 was moderately expressed in TPC-1 and B-CPAP of PTC cell lines.Transfection with β6-si RNA could significantly reduce the expression of integrin β6 in cells,while transfection with integrin β6 overexpressed plasmid could significantly increase the expression of integrin β6 in cells.Interference with integrin β6 expression inhibited the proliferation and invasion of both types of cells,while overexpression of integrin β6 significantly promoted the proliferation and invasion of PTC cells.Conclusion and significanceThis section clarifies the expression of integrin β6 in two types of PTC cells,and explores the influence of integrin β6 on the malignant biological behavior of PTC cells,and finds that integrin β6 can significantly promote the proliferation and invasion ability of PTC cells.This section clarifies the role of integrin β6 in the malignant biological behavior of PTC cells,providing a prerequisite for further study on its mechanism.Part Ⅲ INTEGRIN β6 PLAYS A ROLE IN PTC BY UP-REGULATING THE EXPRESSION AND SECRETION OF MMP-9 OBJECTIVEStudies have found that MMP-9 is one of the important molecules for tumor invasion and metastasis.However,whether MMP-9 can play a role as a downstream target factor of integrin β6 in PTC remains unclear.This section will focus on the effect of integrin β6 on MMP-9 expression.Methods1.Real-time PCR and Western-Blot were used to detect the expressions of MMP-9 in TPC-1 and B-CPAP of two kinds of PTC cells respectively from the m RNA and protein levels.2.The expression of MMP-9 was detected by Real-time PCR,Western-Blot and ELISAafter intervention of β6 expression in two PTC cell lines.ResultsWe used real-time PCR,Western-Blot and ELISA to confirm the expression of MMP-9 in PTC cells and the secretion of MMP-9 that regulated by integrin β6.Conclusion and significanceWe found the connection between integrin β6 and MMP-9 in this part of the cell experiment,and confirmed that integrin β6 can promote the expression and secretion of MMP-9 in PTC cells,suggesting that integrin β6 may play an important role in the process of PTC invasion and metastasis by up-regulating the expression of MMP-9.