title: Cellular response to an antisense-mediated shift of Bcl-x pre-mRNA splicing and antineoplastic agents.
abstract: Overexpression of Bcl-xL, an anti-apoptotic member of the Bcl-2 family, negatively correlates with the sensitivity of various cancers to chemotherapeutic agents. We show here that high levels of expression of Bcl-xL promoted apoptosis of cells treated with an antisense oligonucleotide (5'Bcl-x AS) that shifts the splicing pattern of Bcl-x pre-mRNA from the anti-apoptotic variant, Bcl-xL, to the pro-apoptotic variant, Bcl-xS. This surprising finding illustrates the advantage of antisense-induced modulation of alternative splicing versus down-regulation of targeted genes. It also suggests a specificity of the oligonucleotide effects since non-cancerous cells with low levels of Bcl-xL should resist the treatment. 5'Bcl-x AS sensitized cells to several antineoplastic agents and radiation and was effective in promoting apoptosis of MCF-7/ADR cells, a breast cancer cell line resistant to doxorubicin via overexpression of the mdr1 gene. Efficacy of 5'Bcl-x AS combined with chemotherapeutic agents in the PC3 prostate cancer cell line may be translated to clinical prostate cancer since recurrent prostate cancer tissue samples expressed higher levels of Bcl-xL than benign prostate tissue. Treatment with 5'Bcl-x AS may enhance the efficacy of standard anti-cancer regimens and should be explored, especially in recurrent prostate cancer.
authors.affiliation: UNC Lineberger Comprehensive Cancer Center and Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599-7295, USA.
authors.forename: Danielle R
authors.initials: DR
authors.lastname: Mercatante
authors.forename: James L
authors.initials: JL
authors.lastname: Mohler
authors.forename: Ryszard
authors.initials: R
authors.lastname: Kole
mesh_terms: D017398:Alternative Splicing; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy; D002945:Cisplatin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004317:Doxorubicin / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008957:Models, Genetic; D009841:Oligonucleotides / Q000494:pharmacology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D011467:Prostate / Q000187:drug effects / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000378:metabolism; D011485:Protein Binding; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology; D012008:Recurrence; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012260:Ribonucleases / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured; D051020:bcl-X Protein
chemical_list: D000970:Antineoplastic Agents; C494811:BCL2L1 protein, human; D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D011838:Radiation-Sensitizing Agents; D051020:bcl-X Protein; D012313:RNA; D004317:Doxorubicin; D012260:Ribonucleases; D002945:Cisplatin