Methioninase gene therapy with selenomethionine induces apoptosis in bcl-2-overproducing lung cancer cells.

Abstract

We have previously shown that the toxic pro-oxidant methylselenol is released from selenomethionine (SeMET) by cancer cells transformed with the adenoviral methionine alpha,gamma-lyase (methioninase, MET) gene cloned from Pseudomonas putida. Methylselenol damaged the mitochondria via oxidative stress, and caused cytochrome c release into the cytosol thereby activating caspase enzymes and thereby apoptosis. However, gene therapy strategies are less effective if tumor cells overexpress the antiapoptotic mitochondrial protein bcl-2. In this study, we investigated whether rAdMET/SeMET was effective against bcl-2-overproducing A549 lung cancer cells. We established two clones of the human lung cancer A549 cell line that show moderate and high expression levels of bcl-2, respectively, compared to the parent cell line, which has very low bcl-2 expression. Staurosporine-induced apoptosis was inhibited in the bcl-2-overproducing clones as well as in the parental cell line. In contrast to staurosporine, apoptosis was induced in the bcl-2-overproducing clones as well as the parental cell line by AdMET/SeMET. Apoptosis in the rAdMET-SeMET-treated cells was determined by fragmentation of nuclei, and release of cytochrome c from mitochondria to the cytosol. A strong bystander effect of AdMET/SeMET was observed on A549 cells as well as the bcl-2-overproducing clones. rAdMET/SeMET prodrug gene therapy is therefore a promising novel strategy effective against bcl-2 overexpression, which has blocked other gene therapy strategies.

• Authors: Norio Yamamoto, Anshu Gupta, Mingxu Xu, Kenji Miki, Yoshihide Tsujimoto, Hiroyuki Tsuchiya, Katsuro Tomita, A R Moossa, R M Hoffman
• Journal: Cancer gene therapy (Cancer Gene Ther) Vol. 10 Issue 6 Pg. 445-50 (Jun 2003) ISSN: 0929-1903 [Print] England
• PMID: 12768189 (Publication Type: Journal Article)

Chemical References

• Coloring Agents
• Oxidants
• Proto-Oncogene Proteins c-bcl-2
• Tetrazolium Salts
• Thiazoles
• Cytochromes c
• Selenomethionine
• Carbon-Sulfur Lyases
• L-methionine gamma-lyase
• thiazolyl blue
• Staurosporine
• Bisbenzimidazole

Topics

• Apoptosis
• Bisbenzimidazole (pharmacology)
• Blotting, Western
• Carbon-Sulfur Lyases (genetics)
• Cell Line, Tumor
• Cell Nucleus (metabolism)
• Cell Survival
• Coloring Agents (pharmacology)
• Cytochromes c (metabolism)
• Cytosol (metabolism)
• DNA Fragmentation
• Enzyme-Linked Immunosorbent Assay
• Genetic Therapy (methods)
• Humans
• Lung Neoplasms (metabolism, therapy)
• Mitochondria (metabolism)
• Models, Biological
• Oxidants (pharmacology)
• Oxidative Stress
• Proto-Oncogene Proteins c-bcl-2 (biosynthesis)
• Pseudomonas putida (genetics)
• Selenomethionine (metabolism)
• Staurosporine (pharmacology)
• Tetrazolium Salts (pharmacology)
• Thiazoles (pharmacology)
• Transfection