circRNA-MAP3K1/miR-203/Bmi-1轴调控甲状腺乳头状癌侵袭转移的机制研究OA

Objective To investigate the molecular mechanism of circular RNA(circRNA)-mitogen-activated protein kinase kinase kinase 1(MAP3K1)/miR-203/B cell-specific Moloney murine leukemia virus integration site 1(Bmi-1)axis in regulating invasion and metastasis of papillary thyroid carcinoma(PTC).Methods Tumor tissues and adjacent normal tissues were retrospectively collected from patients diagnosed with PTC by pathological examination in Affiliated Hangzhou First People's Hospital,School of Medicine,Westlake University from January 2022 to December 2023.Differentially expressed circRNAs were screened by high-throughput sequencing,and the expression level of circRNA-MAP3K1 in PTC tissues and adjacent normal tissues was verified by qRT-PCR.Bioinformatics prediction was used to screen miR-203 as the miRNA interacting with circRNA-MAP3K1,and Bmi-1 as the target gene of miR-203.PTC cell lines(BHP2-7 and TPC-1 cells)were selected for circRNA-MAP3K1 knockdown and overexpression.Cell counting kit-8 assay,colony formation assay,Transwell assay and wound healing assay were used to detect the effects on cell proliferation,colony formation,invasion and migration abilities.The dual luciferase reporter assay was used to verify the targeted binding between miR-203 and Bmi-1.The effect of circRNA-MAP3K1 on tumor proliferation in vivo was verified by nude mouse subcutaneous tumorigenesis assay.Results The expression level of circRNA-MAP3K1 in PTC tissues was significantly higher than that in adjacent normal tissues(P=0.003).BHP2-7 cell experiments showed that knockdown of circRNA-MAP3K1 significantly inhibited the proliferation,colony formation and invasion abilities of PTC cells(all P＜0.05),while overexpression of circRNA-MAP3K1 promoted the proliferation,colony formation and invasion abilities(all P＜0.05).In TPC-1 cells,the relative luciferase activity,cell proliferation and colony formation ability in the miR-203 group were all lower than those in the normal control(NC)group(all P＜0.05).Dual-luciferase reporter assay verified that miR-203 targeted the 3'-untranslated region of Bmi-1.The relative luciferase activity in the miR-203+mutant Bmi-1 group was significantly higher than that in the miR-203+wild-type Bmi-1 group(P=0.003).The cell proliferation and invasion abilities in the miR-203 mimic group were lower than those in the miR-203 NC group(both P＜0.05),while the cell proliferation and invasion abilities in the miR-203 mimic+Bmi-1 group were markedly higher than those in the miR-203 mimic group(both P＜0.05).Nude mouse subcutaneous tumorigenesis assay verified that circRNA-MAP3K1 promoted tumor proliferation in vivo,the weight and tumor volume of nude mice increased significantly on the 28th day after inoculation(both P＜0.01).Conclusion circRNA-MAP3K1 is highly expressed in PTC tissues,and promotes invasion and metastasis of PTC mainly by regulating the circRNA-MAP3K1/miR-203/Bmi-1 axis.