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.
Mercatante
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DR
Lineberger Comprehensive Cancer Center and the Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599-7295, USA.
Bortner
C D
CD
Cidlowski
J A
JA
Kole
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R
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