Autori: Al-Harbi S, Hill BT, Mazumder S, Singh K, Devecchio J, Choudhary G, Rybicki LA, Kalaycio M, Maciejewski JP, Houghton JA, Almasan A

Editorial: Blood, 118 (13), p.3579-90, 2011.

Rezumat:

The antiapoptotic BCL-2 proteins regulate lymphocyte survival and are over-expressed in lymphoid malignancies, including chronic lymphocytic leukemia. The small molecule inhibitor ABT-737 binds with high affinity to BCL-2, BCL-XL, and BCL-W but with low affinity to MCL-1, BFL-1, and BCL-B. The active analog of ABT-737, navitoclax, has shown a high therapeutic index in lymphoid malignancies; developing a predictive marker for it would be clinically valuable for patient selection or choice of drug combinations. Here we used RT-PCR as a highly sensitive and quantitative assay to compare expression of antiapoptotic BCL-2 genes that are known to be targeted by ABT-737. Our findings reveal that the relative ratio of MCL-1 and BFL-1 to BCL-2 expression provides a highly significant linear correlation with ABT-737 sensitivity (r = 0.6, P < .001). In contrast, antiapoptotic transcript levels, used individually or in combination for high or low affinity ABT-737-binding proteins, could not predict ABT-737 sensitivity. The (MCL-1 + BFL-1)/BCL-2 ratio was validated in a panel of leukemic cell lines subjected to genetic and pharmacologic manipulations. Changes after ABT-737 treatment included increased expression of BFL-1 and BCL-B that may contribute to treatment resistance. This study defines a highly significant BCL-2 expression index for predicting the response of CLL to ABT-737.

Cuvinte cheie: ABT-737, Bcl-2 family, Chronic lymphocytic leukemia, predictive marker

URL: http://www.ncbi.nlm.nih.gov/pubmed/21772052