Venetoclax and alvocidib are both cytotoxic to acute myeloid leukemia cells resistant to cytarabine and clofarabine

• Published in: BMC cancer Vol. 20; no. 1; pp. 984 - 13
• Main Authors: Nishi, Rie, Shigemi, Hiroko, Negoro, Eiju, Okura, Miyuki, Hosono, Naoko, Yamauchi, Takahiro
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 12-10-2020; BioMed Central; BMC
• Subjects: Acute myeloid leukemia; Alvocidib; Antibodies; Antineoplastic Combined Chemotherapy Protocols - pharmacology; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Apoptosis; Bcl-2; Bcl-2 protein; Bridged Bicyclo Compounds, Heterocyclic - pharmacology; Bridged Bicyclo Compounds, Heterocyclic - therapeutic use; Cancer; Care and treatment; Cell cycle; Cell growth; Cell Proliferation; Chemotherapy; Clofarabine (CAFdA); Clofarabine - pharmacology; Clofarabine - therapeutic use; Cytarabine; Cytarabine (ara-C); Cytarabine - pharmacology; Cytarabine - therapeutic use; Cytotoxicity; Deoxycytidine kinase; Deoxyguanosine; Deoxyguanosine kinase; Deoxyribonucleic acid; DNA; Drug resistance; Flavonoids - pharmacology; Flavonoids - therapeutic use; Flavopiridol; Health aspects; Humans; Intracellular; Kinases; Leukemia; Leukemia, Myeloid, Acute - drug therapy; Lymphoma; Mcl-1; Mcl-1 protein; Myeloid leukemia; Nucleoside analogs; Piperidines - pharmacology; Piperidines - therapeutic use; Sulfonamides - pharmacology; Sulfonamides - therapeutic use; Venetoclax; St Louis Missouri; United Kingdom > UK; United States > US; Japan; Bcl-2; Clofarabine (CAFdA); Mcl-1; Cytarabine (ara-C); Venetoclax; Alvocidib
• ISSN: 1471-2407; 1471-2407
• 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.