Differential Regulation of Telomeric Complex by BCR-ABL1 Kinase in Human Cellular Models of Chronic Myeloid Leukemia-From Single Cell Analysis to Next-Generation Sequencing.

Anna Deregowska,Tomasz Stoklosa,Katarzyna Pruszczyk,Marcin M. Machnicki,Monika Pepek,Maciej Wnuk

doi:10.3390/genes11101145

Anna Deregowska, Tomasz Stoklosa + Show 4 more

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https://doi.org/10.3390/genes11101145

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Abstract

Telomeres are specialized nucleoprotein complexes, localized at the physical ends of chromosomes, that contribute to the maintenance of genome stability. One of the features of chronic myeloid leukemia (CML) cells is a reduction in telomere length which may result in increased genomic instability and progression of the disease. Aberrant telomere maintenance in CML is not fully understood and other mechanisms such as the alternative lengthening of telomeres (ALT) are involved. In this work, we employed five BCR-ABL1-positive cell lines, namely K562, KU-812, LAMA-84, MEG-A2, and MOLM-1, commonly used in the laboratories to study the link between mutation, copy number, and expression of telomere maintenance genes with the expression, copy number, and activity of BCR-ABL1. Our results demonstrated that the copy number and expression of BCR-ABL1 are crucial for telomere lengthening. We observed a correlation between BCR-ABL1 expression and telomere length as well as shelterins upregulation. Next-generation sequencing revealed pathogenic variants and copy number alterations in major tumor suppressors, such as TP53 and CDKN2A, but not in telomere-associated genes. Taken together, we showed that BCR-ABL1 kinase expression and activity play a crucial role in the maintenance of telomeres in CML cell lines. Our results may help to validate and properly interpret results obtained by many laboratories employing these in vitro models of CML.

Highlights

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm caused by reciprocal translocation t(9;22)(q34;q11), resulting in the formation of the Philadelphia chromosome and BCR-ABL1 fusion oncogene [1,2]
The gene copy numbers of BCR-ABL1, Janus kinase 2 (JAK2) and PDGFRB are presented as representative microphotographs of nuclei after hybridization with BCR-ABL1 t(9;22) fusion probe, JAK2 (9p24) break probe and PDGFRB (5q32) break probe (Figure 1a, Supplementary Figure S1)
The fluorescence in situ hybridization (FISH) analysis revealed that all chronic myeloid leukemia (CML) cell lines have a balanced t(9;22) translocation, based on a fusion of the 30 ABL1 region at 9q34 with the 50 BCR region at

Summary

Introduction

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm caused by reciprocal translocation t(9;22)(q34;q11), resulting in the formation of the Philadelphia chromosome and BCR-ABL1 fusion oncogene [1,2]. The hybrid gene BCR-ABL1 undergoes translation into chimeric protein, which is a constitutively active tyrosine kinase which phosphorylates several target proteins and in effect. Genes 2020, 11, 1145 enables expansion of leukemic stem and progenitor cells. The introduction of tyrosine kinase inhibitors (TKIs) to the therapy of CML significantly improved the outcome for the great majority of patients, there is still a minor group of patients who develop drug resistance and are at risk of progression. One of the features of BP-CML is genomic instability when leukemic stem cells acquire additional genetic changes that may cause drug resistance and lead to disease relapse [5]

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