A New Inhibitor Of Histone Deacetylase LBH589Induces Apoptosis Of Multiple Myeloma Cells And Its Reversal Of Drug Resistance Mechanism Research In Vitro

Objective:A new generation of histone deacetylase inhibitor, LBH589, was explored as a single-drug or combination with bortezomib, a proteasome inhibitor against multiple myeloma (MM) cells produce effect produces extremely effects on molecular mechanism, looking for a new target for tumor therapy and provide experimental basis.Methods:By using4methyl thiazolyl blue (MTT) method for the detection of LBH589of10,20,50nmol/L, and50nmol/L combined respectively with bortezomib of10,20nmol/L on growth inhibition of (U266, dexamethasone resistance of MM1R) cells at24and48h, Flow cytometry was used to detect the effect on MM1R cells at48h on cell cycle and cell apoptosis. By Western blot analysis, LBH589(0,10,20,50nmol/L)at24h, expression of histone H4acetylation and PARP gene, BCL-X gene on MMIR cells were detected, By real-time fluorescence quantitative PCR analysis LBH589(0,20,50nmol/L) at24h,48h, expression of caspase-3, APAF-1and TOSO on MMIR cells were detected.Results:1MTT results showed that Single LBH589and that combined with bortezomib were able to suppress U266and MMIR cell growth, and the drug concentration and action time were positively correlated, in a dose-and time-dependent, however, the group of single LBH589was less effective than the combined group (p<0.05).2Single LBH589and that combined with bortezomib role of MMIR cells after48h, flow cytometry showed G0/G1phase cells gradually increased, while cells at G2/M and S phases decreased gradually. Cells arrested at G0/G1phase, while MMIR cell apoptosis rate increased in dose dependent manner. however, the group of single LBH589was less effective than the combined group (p<0.05).3Western blot analysis showed that different concentrations of LBH589showed at24h the up-regulation on expression of the histone H4acetylation and PARP,while down-regulation on expression of the BCL-X in MM1R cells in a dose-dependent manner (p<0.05).4real-time fluorescence quantitative PCR analysis showed that different concentrations of LBH589showed at24h,48h,the up-regulation on expression of the caspase-3and APAF-1,while down-regulation on expression of the TOSO in MM1R cells in a dose-dependent manner (p<0.05).Conclusion:1LBH589on human multiple myeloma cells (U266, MM1R) with growth inhibition.2LBH589through the arrest of the cell cycle, apoptosis induced by the U266, MM1R cell growth inhibition.3LBH589and bortezomib combined on myeloma cell function have a synergistic effect.4LBH589can activate pro-apoptotic genes APAF-1, Caspase-3, PARP gene expression is upregulated by caspase pathway, induces apoptosis of myeloma resistance.5LBH589could promote the multiple myeloma resistant cells of histone acetylation to high TOSO and BCL-X gene expression and reversal of drug resistance is reduced, to promote cell apoptosis.