cytochrome-c-t and 1-2-dielaidoylphosphatidylethanolamine

Chemotherapy has been used for treatment of breast cancer but with limited success. We characterized the effects of bcl-2 antisense and cisplatin combination therapy in two human isogenic breast carcinoma cells p53(+)MCF-7 and p53(-)MCF-7/E6. The transferrin-facilitated lipofection strategy we have developed yielded same transfection efficiency in both cells. Bcl-2 antisense delivered with this strategy significantly induced more cell death, apoptosis, and cytochrome c release in MCF-7/E6 than in MCF-7, but did not affect Fas level in both cells and activated caspase-8 equally. Cisplatin exerted same effects on cell viability and apoptosis in both cells, but released smaller amounts of cytochrome c while activated more caspase-8 in MCF-7/E6. The combination treatment yielded greater effects on cell viability, apoptosis, cytochrome c release, and caspase-8 activation than individual treatments in both cells although p53(-) cells were more sensitive. The potentiated activation of caspase-8 in the combination treatment suggested that caspase-8-mediated (but cytochrome c-independent) apoptotic pathway is the major contributor of the enhanced cell killing. Thus, bcl-2 antisense delivered with transferrin-facilitated lipofection can achieve the efficacy of killing breast cancer cells and sensitizing them to chemotherapy. Bcl-2 antisense and cisplatin combination treatment is a potentially useful therapeutic strategy for breast cancer irrespective of p53 status.

Topics: Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Blotting, Western; Caspase 8; Caspases; Cell Line, Tumor; Cell Survival; Cisplatin; Cytochromes c; fas Receptor; Gene Transfer Techniques; Genes, p53; Genetic Therapy; Humans; Inhibitory Concentration 50; Liposomes; Models, Statistical; Necrosis; Oligonucleotides, Antisense; Phosphatidylethanolamines; Proto-Oncogene Proteins c-bcl-2; Tetrazolium Salts; Thiazoles; Transfection; Transferrin; Tumor Suppressor Protein p53

The interaction of phenethyl alcohol with model membranes and its effect on translocation of the chemically prepared mitochondrial precursor protein apocytochrome c across a lipid bilayer was studied. Phenethyl alcohol efficiently penetrates into monolayers and causes acyl chain disordering judged from deuterium nuclear magnetic resonance measurements with specific acyl chain-deuterated phospholipids. Translocation of apocytochrome c across a phospholipid bilayer was stimulated on addition of phenethyl alcohol indicating that the efficiency of translocation of this precursor protein is enhanced due to a disorder of the acyl chain region of the bilayer.

Topics: Apoproteins; Biological Transport; Cytochrome c Group; Cytochromes c; Ethanol; Lipid Bilayers; Magnetic Resonance Spectroscopy; Membrane Lipids; Mitochondria; Phenylethyl Alcohol; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylserines; Phospholipids; Protein Precursors; Trypsin