Modification of alternative splicing of Bcl-x pre-mRNA in prostate and breast cancer cells. analysis of apoptosis and cell death.
There is ample evidence that deregulation of apoptosis results in the development, progression, and/or maintenance of cancer. Since many apoptotic regulatory genes (e.g. bcl-x) code for alternatively spliced protein variants with opposing functions, the manipulation of alternative splicing presents a unique way of regulating the apoptotic response. Here we have targeted oligonucleotides antisense to the 5'-splice site of bcl-x(L), an anti-apoptotic gene that is overexpressed in various cancers, and shifted the splicing pattern of Bcl-x pre-mRNA from Bcl-x(L) to Bcl-x(S), a pro-apoptotic splice variant. This approach induced significant apoptosis in PC-3 prostate cancer cells. In contrast, the same oligonucleotide treatment elicited a much weaker apoptotic response in MCF-7 breast cancer cells. Moreover, although the shift in Bcl-x pre-mRNA splicing inhibited colony formation in both cell lines, this effect was much less pronounced in MCF-7 cells. These differences in responses to oligonucleotide treatment were analyzed in the context of expression of Bcl-x(L), Bcl-x(S), and Bcl-2 proteins. The results indicate that despite the presence of Bcl-x pre-mRNA in a number of cell types, the effects of modification of its splicing by antisense oligonucleotides vary depending on the expression profile of the treated cells.
Lineberger Comprehensive Cancer Center and the Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599-7295, USA.
D R
DR
Mercatante
C D
CD
Bortner
J A
JA
Cidlowski
R
R
Kole
D017398:Alternative Splicing; D017209:Apoptosis; D001943:Breast Neoplasms; D016923:Cell Death; D005260:Female; D005434:Flow Cytometry; D005809:Genes, Regulator; D014644:Genetic Variation; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019284:Thapsigargin / Q000494:pharmacology; D014162:Transfection; D014407:Tumor Cells, Cultured; D051020:bcl-X Protein
C494811:BCL2L1 protein, human; D020033:Protein Isoforms; D019253:Proto-Oncogene Proteins c-bcl-2; D012322:RNA Precursors; D051020:bcl-X Protein; D019284:Thapsigargin