Adenoviral Bid overexpression induces caspase-dependent cleavage of truncated Bid and p53-independent apoptosis in human non-small cell lung cancers.
Proapoptotic gene transfer to promote death or to augment killing by DNA-damaging agents represents a promising strategy for cancer therapy. We have constructed an adenoviral Tet-Off trade mark vector with tightly controlled expression of Bid (Ad-Bid) (Clontech, Palo Alto, CA). Using the non-small cell lung cancer cell lines H460, H358, and A549, low dose Ad-Bid was shown to induce high levels of full-length Bid as well as caspase-3 and -9 activity. Although only a small fraction of Bid was processed to truncated Bid (a step inhibited by benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone), Ad-Bid gene transfer resulted in mitochondrial changes consistent with apoptosis (mitochondrial depolarization, cytochrome c release), DNA fragmentation, and a dramatic loss of cell viability. The proapoptotic effects of Ad-Bid were independent of p53 status and were augmented markedly by caspase-8 activators such as the DNA-damaging agent cisplatin. When Ad-Bid and cisplatin were used together, chemosensitivity was restored in p53-null H358 cells, increasing death from 35% following treatment with cisplatin and Ad-LacZ to >90% death with Ad-Bid and cisplatin (Ad-Bid alone induced 50% cell death under these conditions). Ad-Bid can induce apoptosis in malignant cells and enhance chemosensitivity in the absence of p53, suggesting this approach as a potential cancer therapy.
Fukazawa
Takuya
T
Department of Biomedical Sciences, University of California, Riverside, California 92521, USA.
Walter
Barbara
B
Owen-Schaub
Laurie B
LB
D000256:Adenoviridae / Q000235:genetics*; D017209:Apoptosis; D051023:BH3 Interacting Domain Death Agonist Protein; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism / Q000473:pathology*; D002352:Carrier Proteins / Q000096:biosynthesis*; D020169:Caspases / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology / Q000627:therapeutic use; D004249:DNA Damage; D053938:DNA Fragmentation; D005434:Flow Cytometry; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology*; D008564:Membrane Potentials; D008928:Mitochondria / Q000378:metabolism; D013997:Time Factors; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D002352:Carrier Proteins; D016159:Tumor Suppressor Protein p53; D020169:Caspases; D002945:Cisplatin