Bcl-xl antisense treatment induces apoptosis in breast carcinoma cells.
Upregulated expression of bcl-xL is involved in the initiation and progression of breast cancer by inhibiting tumor cell apoptosis. Here we describe the use of the 2;-O-methoxy-ethoxy antisense oligonucleotide 4259 targeting nucleotides 687-706 of the bcl-xL mRNA, a sequence that does not occur in the pro-apoptotic bcl-xS transcript, to restore apoptosis in estrogen-dependent and independent breast carcinoma cells. The antisense effect of oligonucleotide 4259 was examined on the mRNA and protein level using real-time PCR and Western blot analysis, respectively, and the induction of cell death was investigated in viability and apoptosis assays. Treatment of MCF7 cells with oligonucleotide 4259 at a concentration of 600 nM for 20 hr decreased bcl-xL mRNA and protein levels by more than 80% and 50%, respectively. This resulted in the induction of apoptosis characterized by mitochondrial cytochrome c release, decrease of mitochondrial transmembrane potential, and the appearance of condensed nuclei in approximately 40% of cells. Moreover, oligonucleotide 4259 efficiently downregulated bcl-xL expression and decreased cell growth in the breast carcinoma cell lines T-47D, ZR-75-1, and MDA-MB-231. Our data emphasize the importance of bcl-xL as a survival factor for breast carcinoma cells and suggest that oligonucleotide 4259 deserves further investigations for use in breast cancer therapy.
Division of Oncology, Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.
A P
AP
Simões-Wüst
R A
RA
Olie
O
O
Gautschi
S H
SH
Leech
R
R
Häner
J
J
Hall
D
D
Fabbro
R A
RA
Stahel
U
U
Zangemeister-Wittke
D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D015536:Down-Regulation; D004967:Estrogens / Q000502:physiology; D006801:Humans; D009376:Neoplasms, Hormone-Dependent / Q000473:pathology; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014407:Tumor Cells, Cultured / Q000187:drug effects; D051020:bcl-X Protein
C494811:BCL2L1 protein, human; D004967:Estrogens; D016376:Oligonucleotides, Antisense; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051020:bcl-X Protein