| BackgroundRenal cell carcinoma(RCC),derived from renal tubular epithelial cells,is a common malignant tumor of urinary system,which accounts for 3% of the adult tumors.Among them,renal clear cell carcinoma(RCCC)accounts for 70% of renal cell carcinoma.Compared with other types of renal cell carcinoma,the clinical symptoms were more obvious and the metastasis rate was higher.The incidence of RCC is closely related to the local economy.Generally speaking,the economically developed areas are higher than those of the less developed areas.People often suffer from renal cell carcinoma at the age of50-70 years old,and male patients are often 2 times of female patients.Due to the improvement of people’s living standard,the change of dietary structure and the change of living environment,the incidence of renal cell carcinoma was increased obviously.Early and middle stage renal cell carcinoma is treated by surgery.However,there are still 1 /3 patients with advanced renal cell carcinoma,which are not sensitive to radiotherapy and chemotherapy.KAI1,separated by Dong in 1955,is a gene that can specifically inhibit tumor metastasis in human chromosome eleventh,which was transferred to AT6.1 cell line.KAI1 can express CD82 protein.KAI1/CD82 is a member of TM4SF(Transmembrane 4 Superfamily),which essence is glycoprotein.The structure and function of TM4 SF are very similar.TM4 SF has four transmembrane domains,and each transmembrane region contains polar amino acids,they are highly conserved,which determines that TM4 SF plays an important role in the malignant biological behavior of tumor cells.As one of the members of TM4 SF,KAI1/CD82 has been proved to be related to the regulation of cell adhesion.KAI1/CD82 has been proved to be a negative regulator of oncogenes in prostate cancer,lung cancer,bladder cancer,esophageal cancer,primary melanoma,colorectal cancer,gastric cancer,cervical cancer and nasopharyngeal carcinoma.Recent studies have found that KAI1/CD82 could be stably expressed in renal clear cell carcinoma cell line 786-0,and the biological behavior of 786-0 such as cell adhesion,proliferation and invasion were regulated by KAI1/CD82.β-catenin is an important cytoplasmic protein,which was originally found as an adhesion factor,may be involved in the regulation of intercellular adhesion.As an important cytoplasmic multifunctional protein,β-catenin plays an important role in the Wnt signal transduction as well as the core protein.From cytoplasm to the nucleus,β-catenin can bind to the TCF/LEF transcription factor in the nucleus,forming a complex to regulate the expression of downstream target genes,which is involved in the regulation of cell proliferation and promotes transcription.Wnt proteins bind to the Frizzled receptor on cell membrane,then activate Dishevelled(DSH)receptor protein and inhibit the downstream protein complex(Axin/GSK-3β/APC),which can make the signal molecule β-catenin phosphorylation and degradation.Therefore,the activation of Wnt signaling pathway can inhibit the degradation of β-catenin,increase the concentration of β-catenin in the cytoplasm and transfer it to the nucleus,in which β-catenin can interact with the TCF/LEF transcription factor and promote the expression of specific genes.The abnormal expression of downstream target genes can increase cell proliferation and induce abnormal expression of protein,which leads to accelerated cell carcinogenesis.Therefore,we speculate that KAI1/CD82 can inhibit the progression of renal cell carcinoma via Wnt/β-catenin signaling pathway.In this study,we transfected the renal clear cell carcinoma cell lines 786-0 and OSRC by PLTHR-shKAI1 plasmid to explore its molecular mechanism.ObjectThrough the study of renal cell carcinoma specimens and 786-0 and OSRC renal clear carcinoma cell lines,explore the impact of KAI1/CD82 on the biological behavior of renal cell carcinoma cells,further investigate the molecular mechanism of KAI1/CD82 inhibiting the occurrence and development of renal cell carcinoma by Wnt/ β-catenin signaling pathway.Methodes1.The expression of CD82 and β-catenin in renal cell carcinoma and adjacent tissues were detected by immunohistochemistry and Western blot.2.We extracted the PLTHR-sh KAI1 plasmid and PLTHR-Vector plasmid,transfected 786-0 and OSRC cell lines.3.PLTHR-sh KAI1/PLTHR-Vector plasmid and eGFP-C1 plasmid were co transfected 786-0 and OSRC,the transfection efficiency was observed under fluorescence microscope.4.Effect of PLTHR-sh KAI1 plasmid on the expression of KAI1/CD82 protein in 786-0 andOSRC was detected by Western blot.5.The effects of knockdown KAI1 on the migration,proliferation and invasion of 786-0 and OSRC renal cell carcinoma cell lines were detected by wound healing assay,cell proliferation assay and transwell invasion assay.6.We koncked down KAI1 in 786-0 and OSRC renal cell carcinoma cell lines,detected the expression of Wnt pathway related protein β-catenin,Axin2 and GSK-3β in 786-0 and OSRC by Western blot.Results1.The expression of KAI1/CD82 in renal carcinoma tissues was lower than that in adjacent tissues,and the expression of β-catenin was higher than that in adjacent tissues.2.The transfection efficiency of renal clear cell carcinoma cell lines 786-0 and OSRC is high,can be competent for our experiment.3.PLTHR-sh KAI1 plasmid can make the expression of KAI1/CD82 silence in 786-0 and OSRC cells.4.Knockdown of KAI1/CD82 can enhance the migration,proliferation and invasion of 786-0 and OSRC cell lines.5.Knockdown of KAI1/CD82 can increase the expression of β-catenin and decrease the expression of Axin2 and GSK-3β proteins in 786-0 and OSRC cells.ConclusionThe expression of CD82 in renal cell carcinoma tissues was lower than that in adjacent tissues,and the expression of β-catenin was higher than that in adjacent tissues.KAI1 can inhibit the migration,proliferation and invasion of renal carcinoma cells.KAI1 inhibits the occurrence and development of renal cell carcinoma by Wnt/ β-catenin signaling pathway. |
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