Akt inhibitors induce apoptosis in chronic lymphocytic leukemia cells.
BACKGROUND
The phosphatidylinositol-3-kinase/Akt pathway has been described to be critical in the survival of chronic lymphocytic leukemia cells. In this study we analyzed the effect of two selective chemical inhibitors of Akt (Akti-1/2 and A-443654) on the survival of chronic lymphocytic leukemia cells.


METHODS
Using cytometry we studied the cytotoxic effects of Akt inhibitors on peripheral B and T lymphocytes from patients with chronic lymphocytic leukemia and from healthy donors. We studied the changes induced by Akti-1/2 and A-443654 at the mRNA level by performing reverse transcriptase multiplex ligation-dependent probe amplification. We also studied the changes induced by both Akt inhibitors in some BCL-2 protein family members on chronic lymphocytic leukemia cells by western blotting. Moreover, we analyzed the cytotoxic effect of Akt inhibitors in patients' cells with deleted/mutated TP53.


RESULTS
Both inhibitors induced apoptosis in chronic lymphocytic leukemia cells in a dose-dependent manner. Moreover, B cells from patients with chronic lymphocytic leukemia were more sensitive to Akt inhibitors than T cells from leukemic patients, and B or T cells from healthy donors. Survival factors for chronic lymphocytic leukemia cells, such as interleukin-4 and stromal cell-derived factor-1alpha, were not able to block the apoptosis induced by either Akt inhibitor. Akti-1/2 did not induce any change in the mRNA expression profile of genes involved in apoptosis, while A-443654 induced some changes, including an increase in NOXA and PUMA mRNA levels, suggesting the existence of additional targets for A-443654. Both inhibitors induced an increase in PUMA and NOXA protein levels, and a decrease in MCL-1 protein level. Moreover, Akti-1/2 and A-443654 induced apoptosis irrespective of TP53 status.


CONCLUSIONS
These results demonstrate that Akt inhibitors induce apoptosis of chronic lymphocytic leukemia cells and might be a new therapeutic option for the treatment of chronic lymphocytic leukemia.
de Frias
Mercè
M
Departament de Ciències Fisiològiques II, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.
Iglesias-Serret
Daniel
D
Cosialls
Ana M
AM
Coll-Mulet
Llorenç
L
Santidrián
Antonio F
AF
González-Gironès
Diana M
DM
de la Banda
Esmeralda
E
Pons
Gabriel
G
Gil
Joan
J
D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D001402:B-Lymphocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D001596:Benzylamines / Q000494:pharmacology; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007191:Indazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D010766:Phosphorylation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D011810:Quinoxalines / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
C504035:A 443654; C501521:Akt-I-1,2 compound; D051017:Apoptosis Regulatory Proteins; C438378:BBC3 protein, human; D001596:Benzylamines; D007191:Indazoles; D007211:Indoles; D064549:Myeloid Cell Leukemia Sequence 1 Protein; C498702:PMAIP1 protein, human; D047428:Protein Kinase Inhibitors; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011810:Quinoxalines; D016159:Tumor Suppressor Protein p53; D051057:Proto-Oncogene Proteins c-akt