Treatment options for TP53-mutated lymphoid tumors are very limited. In experimental models, TP53-mutated lymphomas were sensitive to direct inhibition of checkpoint kinase 1 (Chk1), a pivotal regulator of replication. We initially tested the potential of the highly specific Chk1 inhibitor SCH900776 to synergize with nucleoside analogs (NAs) fludarabine, cytarabine and gemcitabine in cell lines derived from B-cell malignancies. In p53-proficient NALM-6 cells, SCH900776 added to NAs enhanced signaling towards Chk1 (pSer317/pSer345), effectively blocked Chk1 activation (Ser296 autophosphorylation), increased replication stress (p53 and γ-H2AX accumulation) and temporarily potentiated apoptosis. In p53-defective MEC-1 cell line representing adverse chronic lymphocytic leukemia (CLL), Chk1 inhibition together with NAs led to enhanced and sustained replication stress and significantly potentiated apoptosis. Altogether, among 17 tested cell lines SCH900776 sensitized four of them to all three NAs. Focusing further on MEC-1 and co-treatment of SCH900776 with fludarabine, we disclosed chromosome pulverization in cells undergoing aberrant mitoses. SCH900776 also increased the effect of fludarabine in a proportion of primary CLL samples treated with pro-proliferative stimuli, including those with TP53 disruption. Finally, we observed a fludarabine potentiation by SCH900776 in a T-cell leukemia 1 (TCL1)-driven mouse model of CLL. Collectively, we have substantiated the significant potential of Chk1 inhibition in B-lymphoid cells.

• Klíčová slova
• SCH900776, TP53, checkpoint kinase 1/Chk1, chronic lymphocytic leukemia, nucleoside analogs,
• MeSH
• apoptóza MeSH
• B-lymfocyty cytologie   MeSH
• buněčný cyklus MeSH
• checkpoint kinasa 1 antagonisté a inhibitory   MeSH
• chronická lymfatická leukemie farmakoterapie   genetika   metabolismus   MeSH
• cytarabin aplikace a dávkování   MeSH
• deoxycytidin aplikace a dávkování   analogy a deriváty   MeSH
• gemcitabin MeSH
• léky antitumorózní - screeningové testy MeSH
• lidé MeSH
• mitóza MeSH
• mutace MeSH
• myši transgenní MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 genetika   MeSH
• nukleosidy genetika   MeSH
• proliferace buněk MeSH
• pyrazoly farmakologie   MeSH
• pyrimidiny farmakologie   MeSH
• signální transdukce MeSH
• viabilita buněk MeSH
• vidarabin aplikace a dávkování   analogy a deriváty   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• checkpoint kinasa 1 MeSH
• CHEK1 protein, human MeSH Prohlížeč
• cytarabin MeSH
• deoxycytidin MeSH
• fludarabine MeSH Prohlížeč
• gemcitabin MeSH
• MK-8776 MeSH Prohlížeč
• nádorový supresorový protein p53 MeSH
• nukleosidy MeSH
• pyrazoly MeSH
• pyrimidiny MeSH
• TP53 protein, human MeSH Prohlížeč
• vidarabin MeSH