title: Establishment and characterization of hypomethylating agent-resistant cell lines, MOLM/AZA-1 and MOLM/DEC-5.
abstract: Two hypomethylating agents (HMAs), azacitidine and decitabine, have demonstrated clinical activities in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML); however, potential problems include development of acquired resistance. HMA-resistant patients have very poor prognosis and this cohort of patients constitutes an important area of research. To understand the mechanisms underlying HMA-resistance and to overcome it, we established an azacitidine-resistant cell line, MOLM/AZA-1 and a decitabine-resistant cell line, MOLM/DEC-5 using MOLM-13. For cytogenetic characterization, we performed microarray-based comparative genomic hybridization (array-CGH), which identified a total of 15 copy number alterations (CNAs). Among these CNAs, eight regions in HMA-resistant cell lines showed CNA patterns distinct from the parental MOLM-13 genome. Single nucleotide polymorphism (SNP) microarray was also performed to obtain a more reliable interpretation of the identified CNAs, and all HMA-resistance-specific CNAs except one detected by array-CGH were successfully validated. In addition to CNAs, copy neutral loss of heterozygosity and mosaic loss events were identified in HMA-resistant cell lines. In our resistant cell lines, MDR-1 was not overexpressed, while DNMT3b was upregulated. Azacitidine and decitabine did not inhibit DNMT1, DNMT3a, or DNMT3b in both HMA-resistant cell lines, while they inhibited the enzymes in parental MOLM-13. We also developed mouse xenograft models using MOLM/AZA-1 and MOLM/DEC-5. Our in vitro and in vivo models of HMA-resistant cell lines will provide clues for the elucidation of molecular mechanisms related to the development of resistance to HMA and tools for the application of novel therapeutics for AML and MDS.
authors.affiliation: Department of Hematology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Eun-Hye
authors.initials: EH
authors.lastname: Hur
authors.affiliation: Cancer Evolution Research Center, College of Medicine, The Catholic University of Korea.|Integrated Research Center for Genome Polymorphism, College of Medicine, The Catholic University of Korea.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Jung
authors.affiliation: Department of Hematology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Bon-Kwan
authors.initials: BK
authors.lastname: Goo
authors.affiliation: Department of Hematology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Juhyun
authors.initials: J
authors.lastname: Moon
authors.affiliation: Division of Hematology and Hematological Malignancies, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Yunsuk
authors.initials: Y
authors.lastname: Choi
authors.affiliation: Division of Hemato-Oncology, Hallym University Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, Korea.
authors.forename: Dae Ro
authors.initials: DR
authors.lastname: Choi
authors.affiliation: Integrated Research Center for Genome Polymorphism, College of Medicine, The Catholic University of Korea.|Department of Microbiology, College of Medicine, The Catholic University of Korea.
authors.forename: Yeun-Jun
authors.initials: YJ
authors.lastname: Chung
authors.affiliation: Department of Hematology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Je-Hwan
authors.initials: JH
authors.lastname: Lee
mesh_terms: D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D045744:Cell Line, Tumor; D003582:Cytogenetics; D019175:DNA Methylation / Q000187:drug effects*; D000077209:Decitabine; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D011379:Prognosis
chemical_list: D000077209:Decitabine; D001374:Azacitidine
keywords: MOLM-13; azacitidine; cytogenetics; decitabine; resistance