CLIP1 Gene Inhibits The Metastasis Of Papillary Thyroid Cancer Cells Through The TGFβ-pathway

Objective: To study the role of CLIP1 gene in the occurrence and development of papillary thyroid cancer,and to further clarify its molecular mechanism.Methods:(1)The expression of CLIP1 gene in thyroid cancer patients were analyzed using the online database.(2)Human papillary thyroid cancer TPC-1 cell line with CLIP1 gene stable knockdown was constructed by sh RNA lentivirus technology.The effects of CLIP1 gene knockdown on cell proliferation and migration were detected by CCK8,cell scarfing and Trans-well experiments,and the effects of CLIP1 gene knockdown on the expression levels of epithelial mesenchymal transformation markers and the major downstream target genes of TGFβ pathway of TPC-1 cells were detected by real-time quantitative PCR and western blotting.(3)The effect of CLIP1 gene knockdown on F-actin in TPC-1 cells was detected by immunofluorescence experiment.(4)Papillary thyroid cancer metastasis model was established by tail vein injection in nude mice to observe the effect of CLIP1 gene knockdown on the metastasis of TPC-1cells in vivo.(5)The TGFβ pathway inhibitor LY2157299 was used to explore the role of TGFβ signaling pathway in the process of cell migration caused by CLIP1 gene knockdown.Results:(1)The expression of CLIP1 gene was significantly low in patients with thyroid cancer.(2)After constructing papillary thyroid cancer cells with CLIP1 gene stable knockdown,it was found that there was no significant statistical difference in the CCK8 experiment,but significant statistical differences were shown in the cell scarfing and Trans-well experiments.And it led to a decrease in the expression of E-cadherin and an increase in the expression of N-cadherin and Vimentin.In addition,The expression levels of key target genes downstream of the TGFβ pathway were also increased.(3)After CLIP1 gene knockdown,F-actin aggregated in the cortical region and formed outward protrusions.(4)In vivo experiments of tail vein injection metastasis in nude mice showed that CLIP1 gene knockdown promoted the metastasis of papillary thyroid cancer cells to the lung.(5)Cell migration caused by CLIP1 gene knockdown was partially restored by TGFβ pathway inhibitor.Conclusion: CLIP1 gene inhibits the metastasis of papillary thyroid cancer cells through TGFβ pathway.