Department of Hematology and Oncology, Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka, Eiheiji, Fukui, 910-1193, Japan.
Public Health Center of Tango, 855 Tanba, Mineyama, Kyotango, Kyoto, 627-8570, Japan.
BMC Cancer. 2020 Oct 12;20(1):984. doi: 10.1186/s12885-020-07469-x.
Cytarabine (ara-C) is the major drug for the treatment of acute myeloid leukemia (AML), but cellular resistance to ara-C is a major obstacle to therapeutic success. The present study examined enhanced anti-apoptosis identified in 3 newly established nucleoside analogue-resistant leukemic cell line variants and approaches to overcoming this resistance.
HL-60 human AML cells were used to develop the ara-C- or clofarabine (CAFdA)-resistant variants. The Bcl-2 inhibitor venetoclax and the Mcl-1 inhibitor alvocidib were tested to determine whether they could reverse these cells' resistance.
A 10-fold ara-C-resistant HL-60 variant, a 4-fold CAFdA-resistant HL-60 variant, and a 30-fold CAFdA-resistant HL-60 variant were newly established. The variants demonstrated reduced deoxycytidine kinase and deoxyguanosine kinase expression, but intact expression of surface transporters (hENT1, hENT2, hCNT3). The variants exhibited lower expression of intracellular nucleoside analogue triphosphates compared with non-variant HL-60 cells. The variants also overexpressed Bcl-2 and Mcl-1. Venetoclax as a single agent was not cytotoxic to the resistant variants. Nevertheless, venetoclax with nucleoside analogs demonstrated synergistic cytotoxicity against the variants. Alvocidib as a single agent was cytotoxic to the cells. However, alvocidib induced G1 arrest and suppressed the cytotoxicity of the co-administered nucleoside analogs.
Three new nucleoside analogue-resistant HL-60 cell variants exhibited reduced production of intracellular analogue triphosphates and enhanced Bcl-2 and Mcl-1 expressions. Venetoclax combined with nucleoside analogs showed synergistic anti-leukemic effects and overcame the drug resistance.
阿糖胞苷（ara-C）是治疗急性髓系白血病（AML）的主要药物，但细胞对 ara-C 的耐药性是治疗成功的主要障碍。本研究检测了新建立的 3 种核苷类似物耐药白血病细胞系变异体中增强的抗凋亡作用，并探讨了克服这种耐药性的方法。
用人急性髓系白血病 HL-60 细胞株建立 ara-C 或克拉屈滨（CAFdA）耐药变异体。检测 Bcl-2 抑制剂 venetoclax 和 Mcl-1 抑制剂 alvocidib 是否能逆转这些细胞的耐药性。
新建立了 10 倍 ara-C 耐药 HL-60 变异体、4 倍 CAFdA 耐药 HL-60 变异体和 30 倍 CAFdA 耐药 HL-60 变异体。这些变异体显示脱氧胞苷激酶和脱氧鸟苷激酶表达减少，但表面转运体（hENT1、hENT2、hCNT3）表达完整。与非变异体 HL-60 细胞相比，这些变异体细胞内核苷类似物三磷酸的表达较低。这些变异体还过度表达了 Bcl-2 和 Mcl-1。venetoclax 作为单一药物对耐药变异体没有细胞毒性。然而，venetoclax 与核苷类似物联合使用对变异体具有协同细胞毒性。alvocidib 作为单一药物对细胞具有细胞毒性。然而，alvocidib 诱导 G1 期阻滞并抑制联合使用的核苷类似物的细胞毒性。
三种新的核苷类似物耐药 HL-60 细胞变异体表现出细胞内类似物三磷酸产量减少和 Bcl-2 和 Mcl-1 表达增强。venetoclax 联合核苷类似物显示出协同的抗白血病作用，并克服了耐药性。
