Publication details

Presence of heterozygous ATM deletion may not be critical in the primary response of chronic lymphocytic leukemia cells to fludarabine

Authors

ČEJKOVÁ Soňa ROČŇOVÁ Ludmila POTĚŠIL David ŠMARDOVÁ Jana NOVÁKOVÁ Věra CHUMCHALOVÁ Jitka ŽEŽULKOVÁ Dita BORSKÝ Marek DOUBEK Michael BRYCHTOVÁ Yvona POSPÍŠILOVÁ Šárka KLABUSAY Martin MAYER Jiří TRBUŠEK Martin

Year of publication 2009
Type Article in Periodical
Magazine / Source European Journal of Haematology
MU Faculty or unit

Faculty of Medicine

Citation
Web https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0609.2008.01177.x
Doi http://dx.doi.org/10.1111/j.1600-0609.2008.01177.x
Field Oncology and hematology
Keywords chronic lymphocytic leukemia; fludarabine; rituximab; ATM; p53
Description Objectives: Abnormalities of the TP53 or ATM, cooperating tumor-suppressor genes, significantly worsen the treatment options for chronic lymphocytic leukemia (CLL) patients. Although the aberrations seem to be mutually exclusive in this leukemia, inactivation of the former gene leads to worse prognosis. We tested the in vitro sensitivity of the CLL samples with heterozygous ATM deletion to fludarabine and combination of fludarabine and rituximab; the responses were compared with the TP53-abnormal and wild-type (wt) cells in order to delimitate relative significance of ATM deletion. Methods: In vitro analysis was performed on fifty-nine characterized CLL samples using viability assay WST-1. Western blot and real-time RT-PCR were used to monitor the activation of the ATM/p53 pathway. Results and Conclusions: At the clinically relevant concentration of fludarabine, TP53-abnormal samples exhibited markedly higher resistance to fludarabine than the remaining CLL samples (p = 0,012); cohort with ATM deletion was not more resistant than wt cells. A similar induction of the p53 protein and its downstream target genes PUMA and BAX in ATM-deleted and wt cells confirmed that the former subgroup has preserved a critical pro-apoptotic response. Proportions of the samples which had been sensitized to fludarabine by rituximab pre-treatment were insignificantly lower (p = 0.22) in the TP53-abnormal and ATM-deleted subgroups compared to the wt cases (30%; 29%; 50%, respectively). The presence of ATM (11q22-23) deletion in the CLL cells should not be considered an indication of resistance to fludarabine or its combination with rituximab.

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