Re-expression of p16 gene in the myeloma cell line U266 induced by synergy of sodium butyrate and 5-Aza-2'-deoxycytidine

To understand the synergic effect of histone deacetylase inhibitor sodium butyrate (SB) and demethylating agent 5-Aza-2'- deoxycytidine (5-Aza-CdR) on cell growth and to explore the possibility of re-expression of the hypermethylated and silenced p16 gene in the myeloma cell line U266.U266 cells were cultured in RPMI 1640 in the presence of varied doses of SB and 5-Aza-CdR, and the growth curve was obtained by trypan-blue exclusion assay and cell count. The cell cycle was analyzed by flow cytometry and the expression level of mRNA and protein of p16 gene were detected by reverse transcriptase-PCR and Western blotting, respectively.The cell growth was arrested by treatment with 5-Aza-CdR alone or SB alone. Increased inhibition effect was shown in synergic treatment of SB and 5-Aza-CdR. The G(1) phase of cell cycle was arrested by 5-Aza-CdR combined with SB, which, however, did not occur when SB or 5-Aza-CdR was used alone. 5-Aza-CdR alone induced the expression of p16 gene in a concentration-dependent manner, whereas SB alone only induced its low-level expression. The expression level of both mRNA and protein of p16 gene was increased significantly by synergic application of SB and 5-Aza-CdR.Hypermethylated and silenced p16 gene in U266 cell line can be markedly reactivated by synergic treatment with demethylating agent 5-Aza-CdR and histone deacetylase inhibitor SB, and the cell growth can be inhibited and cell cycle arrested at G(1) phase.PubMed011981-42