RESUMO
<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>MiRNA-34a regulates cell cycles by targeting CD44 in human bladder carcinoma cell line J82.</p>