Combination of DNA methylation inhibitor 5‐azacytidine and arsenic trioxide has synergistic activity in myeloma

Abstract

XAF1 is a newly identified candidate tumour-suppressor gene that can antagonise XIAP and sensitise cells to cell death triggers. This study was undertaken to study the effect of 5-azacytidine (AZA) on XAF1 expression in myeloma cells and efficacy of 5-AZA and arsenic trioxide (ATO) combination treatment in myeloma in vivo and in vitro. XAF1 expression was analysed by semi-quantitative PCR and western blotting. Methylation specific PCR was used to detect methylation status of XAF1 promoter CpG islands. RPMI 8226 and XG-7 cells were treated with various concentrations of 5-AZA and ATO. Expression of XAF1 mRNA variants were confirmed by gel electrophoresis and sequencing. Untreated RPMI 8226 cell expresses two variants of XAF1 mRNA. Untreated XG-7 cell has no expression of XAF1. Hypermethylation of XAF1 promoter CpG islands was detected in both cell lines. Both cell lines express full-length XAF1 transcript after treated with 2.5 mumol/L 5-AZA for 72 h. Our studies demonstrated that 5-AZA exhibits anti-myeloma synergy with ATO. In addition, ATO alone, 5-AZA alone, or combination of 5-AZA and ATO was effective in slowing myeloma growth and prolonging survival of myeloma-loaded nude mice. The findings suggested that 5-AZA and ATO may be an effective combination in the therapy of myeloma patients.

The Synergistic Effects of Decitabine Combined with Arsenic Trioxide (ATO) in the Human Myelodysplastic Syndrome Cell Line SKM-1

“…Tong and Fu et al [10,11] found reexpression of p15 and p16 through the demethylation of their promoters in the U266 and MUTZ-1 cell lines, respectively. In addition, a previous study found that arsenic trioxide combined with the demethylation drug azacitidine showed increased demethylation in in vivo and in vitro experiments [12]. The above results suggest that the combination of arsenic trioxide and decitabine may have a similar effect.…”

Arsenic trioxide-mediated growth inhibition of myeloma cells is associated with an extrinsic or intrinsic signaling pathway through activation of TRAIL or TRAIL receptor 2

“…In this regard, it is noteworthy that TRAIL, a TNF superfamily member, ligates two types of receptors: death receptors triggering TRAIL-induced apoptosis (TRAIL R1 and TRAIL R2) and decoy receptors that act as sinks for TRAIL and administering ATO to MM patients. More studies showed a synergic effect when ATO is administered in combination with other anti-MM drugs, such as bortezomib, the DNA methylation inhibitor 5-azacytidine and melphalan et al [31][32][33][34] The findings in this study offer a promising and novel strategy, using ATO to activate TRAIL, in the treatment of myelomas, especially those aggressive myeloma subtypes with low expression of TRAIL, such as MS subgroup with reciprocal translocation (4:14) and MF subgroup with reciprocal translocations (14:16) and (14:20).…”

Aberrant global methylation patterns affect the molecular pathogenesis and prognosis of multiple myeloma

“…[11][12][13] With the exception of one recent study, 14 the epigenetic factors contributing to the pathogenesis of myeloma have been studied on a gene-by-gene basis and, with the use of methylation-specific PCR, several genes have been identified that are hypermethylated, including VHL, XAF1, IRF8, TP53, CDKN2A, CDKN2B, DAPK, SOCS1, CDH1, PTGS2, CCND2, and DCC. [15][16][17][18][19][20][21][22] Promoter hypermethylation of cyclin-dependent kinase inhibitor 2A (CDKN2A) and TGFBR2 have been shown to correlate with poor prognosis in myeloma patients, although the prognostic value of CDKN2A hypermethylation remains debatable. 16,23,24 In this study we used the Infinium array (Illumina) to analyze CpG island promoter methylation with normal PCs, MGUS, myeloma, and PCL samples to identify methylation changes that may contribute to the pathogenesis of myeloma or that could act as prognostic factors.…”