CREB antisense oligonucleotides induce non-apoptotic cell death in proliferating leukemia cells, but not normal hematopoietic cells, by a bizarre non-antisense mechanism.
We report that antisense phosphorothioate oligodeoxyribonucleotides (PS-ODNs) against cyclic AMP response element-binding protein (CREB) induce the death of human leukemia cell lines including HL-60, Kasumi-1 and K562, OCI-AML1a and also primary leukemia cells isolated from patients with acute myelocytic leukemia and chronic myelocytic leukemia in blastic crisis. In contrast, normal human bone marrow CD34+ cells and normal peripheral blood lymphocytes were resistant to the antisense-mediated cell death. We found that antisense-treated HL-60 cells had prominent nuclear fragmentations but lacked apoptotic features including internucleosomal DNA cleavage and TUNEL positivity. Cell cycle analysis demonstrated a remarkable reduction in G1 phase population along with a mild accumulation of S phase and good preservation of G2/M phase, indicating cells died at G2/M without cycling into G1 phase. None of the sense-sequenced PS-ODNs induced cell death. Further, neither the expression nor the message of CREB protein was reduced by antisense treatment, indicating that cell death was mediated by a non-antisense mechanism. On the other hand, no consensus oligonucleotide sequence for cell death induction was detected. Rather, we found a good correlation between the melting temperatures and the anti-proliferative activities of the oligonucleotides. Thus, CREB antisense PS-ODNs selectively induce a non-apoptotic cell death in leukemic cells by an unknown hybridization-dependent mechanism.
Department of Hematology, Research Institute, International Medical Center of Japan, Tokyo.
K
K
Saeki
A
A
Yuo
M
M
Koizumi
K
K
Fujiwara
M
M
Kaneko
F
F
Takaku
Y
Y
Yazaki
D018952:Antigens, CD34 / Q000276:immunology; D001483:Base Sequence; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D016923:Cell Death / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics*; D020287:In Situ Nick-End Labeling; D007938:Leukemia / Q000473:pathology*; D016376:Oligonucleotides, Antisense / Q000737:chemistry / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D018952:Antigens, CD34; D017362:Cyclic AMP Response Element-Binding Protein; D016376:Oligonucleotides, Antisense