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.
Simões-Wüst
A P
AP
Division of Oncology, Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.
Olie
R A
RA
Gautschi
O
O
Leech
S H
SH
Häner
R
R
Hall
J
J
Fabbro
D
D
Stahel
R A
RA
Zangemeister-Wittke
U
U
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