Glutathione promotes the synergistic effects of venetoclax and azacytidine against myelodysplastic syndrome‑refractory anemia by regulating the cell cycle

Xiaobo Wang; Lihua Yuan; Bo Lu; Dongjun Lin; Xiaojun Xu

doi:10.3892/etm.2023.12274

Glutathione promotes the synergistic effects of venetoclax and azacytidine against myelodysplastic syndrome‑refractory anemia by regulating the cell cycle

Exp Ther Med. 2023 Oct 26;26(6):574. doi: 10.3892/etm.2023.12274. eCollection 2023 Dec.

Authors

Xiaobo Wang¹, Lihua Yuan², Bo Lu¹, Dongjun Lin¹, Xiaojun Xu¹

Affiliations

¹ Department of Hematology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen, Guangdong 518107, P.R. China.
² Department of Pediatric Surgery, University of Hong Kong-Shenzhen Hospital, Shenzhen, Guangdong 518000, P.R. China.

Abstract

Azacitidine is a DNA methyltransferase inhibitor that has been used as a singular agent for the treatment of myelodysplastic syndrome-refractory anemia with excess blast-1 and -2 (MDS-RAEB I/II). However, recurrence and overall response rates following this treatment remain unsatisfactory. The combination of azacitidine and venetoclax has been used for the clinical treatment of a variety of hematological diseases due to the synergistic killing effect of the two drugs. Venetoclax is a BCL-2 inhibitor that can inhibit mitochondrial metabolism. In addition, azacitidine has been shown to reduce the levels of myeloid cell leukemia 1 (MCL-1) in acute myeloid leukemia cells. MCL-1 is an anti-apoptotic protein and a potential source of resistance to venetoclax. However, the mechanism underlying the effects of combined venetoclax and azacitidine treatment remains to be fully elucidated. In the present study, the molecular mechanism underlying the impact of venetoclax on the efficacy of azacitidine was investigated by examining its effects on cell cycle progression. SKM-1 cell lines were treated in vitro with 0-2 µM venetoclax and 0-4 µM azacytidine. After 24, 48 and 72 h of treatment, the impact of the drugs on the cell cycle was assessed by flow cytometry. Following drug treatment, changes in cellular glutamine metabolism pathways was analyzed using western blotting (ATF4, CHOP, ASCT2, IDH2 and RB), quantitative PCR (ASCT2 and IDH2), liquid chromatography-mass spectrometry (α-KG, succinate and glutathione) and ELISA (glutamine and glutaminase). Venetoclax was found to inhibit mitochondrial activity though the alanine-serine-cysteine transporter 2 (ASCT2) pathway, which decreased glutamine uptake. Furthermore, venetoclax partially antagonized the action of azacitidine through this ASCT2 pathway, which was reversed by glutathione (GSH) treatment. These results suggest that GSH treatment can potentiate the synergistic therapeutic effects of venetoclax and azacitidine combined treatment on a myelodysplastic syndrome-refractory anemia cell line at lower concentrations.

Keywords: azacitidine; glutathione; mitochondrial glutamine metabolism; myelodysplastic syndrome-refractory anemia; venetoclax.

Grants and funding

Funding: The present study was supported by Sanming Project of Medicine in Shenzhen (grant no. SZSM201911004), Shenzhen Science and Technology Plan Basic Research Project (grant nos. JCYJ20180307150408596 and JCYJ20190809172403604) and Natural Science Foundation of Guangdong Province (grant no. 2019A1515110703).