Antisense BAG-1 sensitizes HeLa cells to apoptosis by multiple pathways.
To study the mechanism of action of BAG-1 in drug-induced apoptosis, we constructed an antisense BAG-1 vector and established a stably transfected cell line from BAG-1-over-expressing HeLa cells. Reduced BAG-1 protein was confirmed by Western blot. Treatment of the antisense BAG-1-transfected cells with the anti-cancer drugs staurosporine, paclitaxel, all-trans retinoic acid (ATRA), and N-(4-hydroxyphenyl) retinamide (4-HPR) resulted in significantly enhanced apoptosis and reduced cell viability relative to vector-transfected cells. While the expression of p53 was increased, the level of Bcl-2 and Bax was decreased. Cells underexpressing BAG-1 had reduced cytosolic cytochrome c level. Treatment with staurosporine and paclitaxel resulted in increased cytochrome c release from mitochondria, whereas there was no change induced by treatment with ATRA and 4-HPR. Our experiments suggest that BAG-1 inhibits anti-cancer drug-induced apoptosis through apoptosis regulation pathways that may involve the mitochondrial Bcl-2/Bax ratio, p53, and differential anti-cancer drug-mediated cytochrome c release.
Xiong
Jieying
J
Memorial University of Newfoundland, Basic Medical Sciences, 300 Prince Philip Dr., St. John's, NL, Canada A1B 3V6.
Chen
Jun
J
Chernenko
Garry
G
Beck
Jessalyn
J
Liu
Hongyu
H
Pater
Alan
A
Tang
Shou-Ching
SC
D000970:Antineoplastic Agents / Q000494:pharmacology*; D016375:Antisense Elements (Genetics) / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects*; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D004268:DNA-Binding Proteins; D015536:Down-Regulation; D004351:Drug Resistance / Q000235:genetics; D017313:Fenretinide / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006367:HeLa Cells; D006801:Humans; D017239:Paclitaxel / Q000494:pharmacology; D015398:Signal Transduction; D019311:Staurosporine / Q000494:pharmacology; D014157:Transcription Factors; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology
D000970:Antineoplastic Agents; D016375:Antisense Elements (Genetics); C091732:BCL2-associated athanogene 1 protein; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D017313:Fenretinide; D014212:Tretinoin; D045304:Cytochromes c; D019311:Staurosporine; D017239:Paclitaxel