PF-114, a Novel Inhibitor of Bcr-Abl Chimeric Tyrosine Kinase, Attenuates Intracellular CrkL Phosphorylation and Kills Chronic Myeloid Leukemia Cells

Background & Aims. The chimeric tyrosine kinase Bcr-Abl triggers malignant transformation of myeloid cells via phosphorylation of a number of substrates including the CrkL adaptor protein. Pharmacological inhibition of Bcr-Abl mediated signaling is a major strategy in treatment of patients with chronic myeloid leukemia (CML). A new specific Bcr-Abl inhibitor (PF-114) was designed using a molecular modeling approach. The paper defines the cytotoxicity of PF-114 against CML cells and its effect on the CrkL phosphorylation.

Methods. The cytotoxicity was determined using the MTT assay. The total intracellular CrKL pool (phosphorylated and non-phosphorylated forms) was determined by means of flow cytometry.

Results. Exposure of Bcr-Abl-positive, K562 cell line to PF-114 blocked intracellular CrkL phosphorylation and caused cell death. In contrast, virtually no phosphorylated CrkL was detectable in Bcr-Abl-negative HL60, U937 and Jurkat leukemia cell lines.

Conclusion. Absence of phosphorylation in Bcr-Abl-negative cells (HL60, U937 and Jurkat) and death of HL60 cells under the effect of PF-114 at concentrations exceeding those required to kill K562 cells supports the emergence of PF-114 as a promising drug candidate for CML.

• E.S. Kolotova N.N. Blokhin Russian Cancer Research Center, 24 Kashirskoye sh., Moscow, Russian Federation, 115478 ; ФГБУ «Российский онкологический научный центр им. Н.Н. Блохина» Минздрава России, Каширское ш., д. 24, Москва, Российская Федерация, 115478
• V.V. Tatarskii N.N. Blokhin Russian Cancer Research Center, 24 Kashirskoye sh., Moscow, Russian Federation, 115478 ; ФГБУ «Российский онкологический научный центр им. Н.Н. Блохина» Минздрава России, Каширское ш., д. 24, Москва, Российская Федерация, 115478
• A.A. Zeifman N.D. Zelinskii Institute of Organic Chemistry, 47 Leninskii pr-t, Moscow, Russian Federation, 119991; Fusion Pharma, 18 bld. 2 Generala Dorokhova str., Moscow, Russian Federation, 119530 ; ФГБУН «Институт органической химии им. Н.Д. Зелинского» РАН, Ленинский пр-т, д. 47, Москва, Российская Федерация, 119991; ООО «Фьюжн Фарма», ул. Генерала Дорохова, д. 18, стр. 2, Москва, Российская Федерация, 119530
• O.V. Stroganov N.D. Zelinskii Institute of Organic Chemistry, 47 Leninskii pr-t, Moscow, Russian Federation, 119991; Fusion Pharma, 18 bld. 2 Generala Dorokhova str., Moscow, Russian Federation, 119530 ; ФГБУН «Институт органической химии им. Н.Д. Зелинского» РАН, Ленинский пр-т, д. 47, Москва, Российская Федерация, 119991; ООО «Фьюжн Фарма», ул. Генерала Дорохова, д. 18, стр. 2, Москва, Российская Федерация, 119530
• V.S. Stroilov N.D. Zelinskii Institute of Organic Chemistry, 47 Leninskii pr-t, Moscow, Russian Federation, 119991; Fusion Pharma, 18 bld. 2 Generala Dorokhova str., Moscow, Russian Federation, 119530 ; ФГБУН «Институт органической химии им. Н.Д. Зелинского» РАН, Ленинский пр-т, д. 47, Москва, Российская Федерация, 119991; ООО «Фьюжн Фарма», ул. Генерала Дорохова, д. 18, стр. 2, Москва, Российская Федерация, 119530
• I.Yu. Titov N.D. Zelinskii Institute of Organic Chemistry, 47 Leninskii pr-t, Moscow, Russian Federation, 119991; Fusion Pharma, 18 bld. 2 Generala Dorokhova str., Moscow, Russian Federation, 119530 ; ФГБУН «Институт органической химии им. Н.Д. Зелинского» РАН, Ленинский пр-т, д. 47, Москва, Российская Федерация, 119991; ООО «Фьюжн Фарма», ул. Генерала Дорохова, д. 18, стр. 2, Москва, Российская Федерация, 119530
• F.N. Novikov N.D. Zelinskii Institute of Organic Chemistry, 47 Leninskii pr-t, Moscow, Russian Federation, 119991; Fusion Pharma, 18 bld. 2 Generala Dorokhova str., Moscow, Russian Federation, 119530 ; ФГБУН «Институт органической химии им. Н.Д. Зелинского» РАН, Ленинский пр-т, д. 47, Москва, Российская Федерация, 119991; ООО «Фьюжн Фарма», ул. Генерала Дорохова, д. 18, стр. 2, Москва, Российская Федерация, 119530
• A.A. Kalinina N.N. Blokhin Russian Cancer Research Center, 24 Kashirskoye sh., Moscow, Russian Federation, 115478 ; ФГБУ «Российский онкологический научный центр им. Н.Н. Блохина» Минздрава России, Каширское ш., д. 24, Москва, Российская Федерация, 115478
• G.G. Chilov N.D. Zelinskii Institute of Organic Chemistry, 47 Leninskii pr-t, Moscow, Russian Federation, 119991; Fusion Pharma, 18 bld. 2 Generala Dorokhova str., Moscow, Russian Federation, 119530 ; ФГБУН «Институт органической химии им. Н.Д. Зелинского» РАН, Ленинский пр-т, д. 47, Москва, Российская Федерация, 119991; ООО «Фьюжн Фарма», ул. Генерала Дорохова, д. 18, стр. 2, Москва, Российская Федерация, 119530
• Aleksandr Al’bertovich Shtil’ N.N. Blokhin Russian Cancer Research Center, 24 Kashirskoye sh., Moscow, Russian Federation, 115478 ; ФГБУ «Российский онкологический научный центр им. Н.Н. Блохина» Минздрава России, Каширское ш., д. 24, Москва, Российская Федерация, 115478

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