The Role Of MIR-548m/CDK6 In The Pathogenesis Of Mantle Cell Lymphoma

Objective: The aim of this study is to explore the expression of mi R-548 m and CDK6 in MCL(mantle cell lymphoma) cells adhesion to FDCs(follicular dendritic cells) and their molecular mechanisms in the carcinogenesis and development of MCL, revealing the biological fuctions of CDK6 inhibitor PD 0332991 and finding out new potential targets for treating MCL.Methods: RT-q PCR and Western Blot were used respectively to test the expression of mi R-548 m and CDK6 in MCL cells adhesion to FDCs. Bioinformatics assay was applied to predict the targets of mi R-548 m, and Western Blot was used to test the expression level of CDK6 after overexpressing or inhibiting mi R-548 m. Luciferase report assay was performed to test whether CDK6 was a direct target of mi R-548 m. Colony forming assay was used to test the colony forming activity in MCL after overexpression of mi R-548 m or knockdown of CDK6. Flow cytometry was applied to test the cell cycle, proliferation and apoptosis, and Western Blot was used to test the expression level of Rb(Retinal Blastoma) protein and p-Rb(Phosphorylated Retinal Blastoma) protein.Results: RT-q PCR and Western Blot showed that cells adhesion to FDCs induced downregulation of mi R-548 m and CDK6 expression in MCL. Bioinformatics assay revealed that mi R-548 m could target the 3’-UTR of CDK6, and there was a negative correlation between the level of mi R-548 m and the CDK6 expression. Luciferase report assay confirmed that 3’-UTR of CDK6 was a direct target of mi R-548 m. Colony forming assay showed that overexpression of mi R-548 m or knockdown of CDK6 significantly suppressed MCL colony formation. Flow cytometry found that PD 0332991 inhibited proliferation of the MCL cells and induced a G0/G1 cell cycle arrest and reduced the cell population in S phase. Western Blot confirmed that PD 0332991 downregulated the level of Phosphorylated Rb protein.Conclusion: FDCs-inducing cell adhesion downregulated the level of mi R-548 m and overexpressed CDK6 in MCL cells; the 3’-UTR of CDK6 was a direcr target of mi R-548 m, FDCs promoted the colony formation of MCL by mi R-548m/CDK6 axis; CDK6 inhibitor PD 0332991 induced a G0/G1 cell cycle arrest and enhanced the suppressing role of mitoxantrone(MTZ) in MCL cells colony formation through suppressing Rb phosphorylation.