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Proteomic Profiling of Imatinib-Sensitive and -Resistant K562 Cell Line to Delineate the Mechanism of Resistance in CML Blast Crisis
CC BY 4.0 · Indian J Med Paediatr Oncol 2024; 45(S 01): S1-S16
DOI: DOI: 10.1055/s-0044-1788209
*Corresponding author: (e-mail: nehaagrawal281995@gmail.com).
Abstract
Background: Imatinib, a tyrosine kinase inhibitor, successfully induces remission in the majority of early-phase chronic myeloid leukaemia patients. However, 80% of terminal phase (BC) patients show resistance, 50% of them despite inhibition of Bcr-Abl activity. This Bcr-Abl independent mechanism of resistance in BC has been investigated.
Materials and Methods: Quantitative phosphoproteome by MS-MS and kinome by array of imatinib-sensitive (K562-S) and -resistant (K562-R) cells were profiled. Further, a key differentiator between the S and R cells, β1-integrin with reduced levels in R, was knocked down (β1-KD) in S cells and the effect on phosphoproteome and kinome was investigated.
Results: We have earlier demonstrated the active Bcr-Abl pathway despite inhibition of Bcr-Abl activity in K562-R and in this study, we associate it with reduced levels of β1-integrin. β1-KD in S cells mimicked an active state of Bcr-Abl pathway components, 14-3-3ԑ and phosphoP38MAPK, as in R. Further, signaling molecules downstream of β1-integrin, FAK and PKCβ, were shown to be less active in β1-KD cells as in K562-R cells. Further, the ERK-MEK pathway molecules were found to be active in β1-KD and K562-R cells. Previous genomic analysis revealed PLAG1 amplification in resistant cells. PLAG1 knockdown in K562-R restored sensitivity toward imatinib and the levels of β1-integrin.
Conclusion: In R cells harboring Bcr-Abl inactivated by imatinib, PLAG1 amplification causes reduced levels of β1-integrin, which in turn leads to the activation of signaling downstream of Bcr-Abl. Thus, starting with chromosomal aberration up to cell signaling, the Bcr-Abl-independent mechanism underlying resistance in BC has been elucidated.
Publication History
Article published online:
08 July 2024
© 2024. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)
Thieme Medical and Scientific Publishers Pvt. Ltd.
A-12, 2nd Floor, Sector 2, Noida-201301 UP, India
*Corresponding author: (e-mail: nehaagrawal281995@gmail.com).
Abstract
Background: Imatinib, a tyrosine kinase inhibitor, successfully induces remission in the majority of early-phase chronic myeloid leukaemia patients. However, 80% of terminal phase (BC) patients show resistance, 50% of them despite inhibition of Bcr-Abl activity. This Bcr-Abl independent mechanism of resistance in BC has been investigated.
Materials and Methods: Quantitative phosphoproteome by MS-MS and kinome by array of imatinib-sensitive (K562-S) and -resistant (K562-R) cells were profiled. Further, a key differentiator between the S and R cells, β1-integrin with reduced levels in R, was knocked down (β1-KD) in S cells and the effect on phosphoproteome and kinome was investigated.
Results: We have earlier demonstrated the active Bcr-Abl pathway despite inhibition of Bcr-Abl activity in K562-R and in this study, we associate it with reduced levels of β1-integrin. β1-KD in S cells mimicked an active state of Bcr-Abl pathway components, 14-3-3ԑ and phosphoP38MAPK, as in R. Further, signaling molecules downstream of β1-integrin, FAK and PKCβ, were shown to be less active in β1-KD cells as in K562-R cells. Further, the ERK-MEK pathway molecules were found to be active in β1-KD and K562-R cells. Previous genomic analysis revealed PLAG1 amplification in resistant cells. PLAG1 knockdown in K562-R restored sensitivity toward imatinib and the levels of β1-integrin.
Conclusion: In R cells harboring Bcr-Abl inactivated by imatinib, PLAG1 amplification causes reduced levels of β1-integrin, which in turn leads to the activation of signaling downstream of Bcr-Abl. Thus, starting with chromosomal aberration up to cell signaling, the Bcr-Abl-independent mechanism underlying resistance in BC has been elucidated.
No conflict of interest has been declared by the author(s).
Publication History
Article published online:
08 July 2024
© 2024. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)
Thieme Medical and Scientific Publishers Pvt. Ltd.
A-12, 2nd Floor, Sector 2, Noida-201301 UP, India