Reversal of cisplatin and multidrug resistance by ribozyme-mediated glutathione suppression.

Abstract

gamma-Glutamylcysteine synthetase (gamma-GCS) is a key enzyme in glutathione (GSH) synthesis, and is thought to play a significant role in intracellular detoxification, especially of anticancer drugs. Increased levels of GSH are commonly found in the drug-resistant human cancer cells. We designed a hammerhead ribozyme against gamma-GCS mRNA (anti-gamma-GCS Rz), which specifically down-regulated gamma-GCS gene expression in the HCT-8 human colon cancer cell line. The aim of this study was to reverse the cisplatin and multidrug resistance for anticancer drugs. The cisplatin-resistant HCT-8 cells (HCT-8DDP cells) overexpressed MRP and MDR1 genes, and showed resistance to not only cisplatin (CDDP), but also doxorubicin (DOX) and etoposide (VP-16). We transfected a vector expressing anti-gamma-GCS Rz into the HCT-8DDP cells (HCT-8DDP/Rz). The anti-gamma-GCS Rz significantly suppressed MRP and MDR, and altered anticancer drug resistance. The HCT-8DDP/Rz cells were more sensitive to CDDP, DOX and VP-16 by 1.8-, 4.9-, and 1.5-fold, respectively, compared to HCT-8DDP cells. The anti-gamma-GCS Rz significantly down-regulated gamma-GCS gene expression as well as MRP/MDR1 expression, and reversed resistance to CDDP, DOX and VP-16. These results suggested that gamma-GCS plays an important role in both cisplatin and multidrug resistance in human cancer cells.

• Authors: J Nagata, H Kijima, H Hatanaka, S Asai, H Miyachi, A Takagi, T Miwa, T Mine, H Yamazaki, M Nakamura, T Kondo, K J Scanlon, Y Ueyama
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 286 Issue 2 Pg. 406-13 (Aug 17 2001) ISSN: 0006-291X [Print] United States
• PMID: 11500053 (Publication Type: Journal Article)
• Copyright: Copyright 2001 Academic Press.

Chemical References

• Antineoplastic Agents
• RNA, Catalytic
• RNA, Neoplasm
• Tetrazolium Salts
• Thiazoles
• Glutamate-Cysteine Ligase
• thiazolyl blue
• Glutathione
• Cisplatin

Topics

• Antineoplastic Agents (therapeutic use)
• Cisplatin (therapeutic use)
• Colonic Neoplasms (genetics, metabolism, therapy)
• Drug Resistance, Multiple
• Drug Resistance, Neoplasm
• Glutamate-Cysteine Ligase (genetics)
• Glutathione (antagonists & inhibitors)
• Humans
• RNA, Catalytic (therapeutic use)
• RNA, Neoplasm (biosynthesis, genetics)
• Tetrazolium Salts (chemistry)
• Thiazoles (chemistry)
• Tumor Cells, Cultured