Abstract: Objective To investigate the role of microRNA-34a (miR-34a) in regulating the cell cycles of bladder cancer cell line
J82 and explore the underlying mechanism. Methods J82 cells were transfected with a miR-34a mimic or an inhibitor to induce
miR-34a overexpression or silencing. The RNA level of miR-34a in the transfected cells was detected by real-time PCR, and
CD44 expressions at the mRNA and protein levels were detected by real-time PCR and Western blotting. Luciferase reporter
assay was used to detect the activation of 3’UTR of CD44, and flow cytometry was performed to analyze the cell cycle changes.
Results The expression level of miR-34a was significantly increased and CD44 expression significantly lowered in cells
transfected with miR-34a mimic; miR-34a inhibitor transfection caused reverse effects on miR-34a and CD44 expressions.
MiR-34a mimics downregulated while miR-34a inhibitor enhanced the activation of 3’UTR of CD44 with corresponding
changes in the expressions of some cell cycle-related proteins. MiR-34a mimics and miR-34a inhibitor induced opposite
changes in J82 cell cycle, which were partly reversed by CD44. Conclusion MiRNA-34a regulates cell cycles by targeting CD44
in human bladder carcinoma cell line J82.