Related Experiment Videos
A glutathione depletion selectively imposed on mu glutathione S-transferase overproducing cells increases nitrogen
C Lunel-Orsini1, G Buttin, B R De Saint Vincent
1Unité de Génétique Somatique, URA CNRS 361, Institut Pasteur, Paris, France.
Abstract:
Glutathione (GSH) contributes to the detoxification of anticancer drugs through the operation of specific glutathione S-transferases (GST) and innate, or acquired, overexpression of this enzyme family has been frequently observed in tumor cell lines. In the GMA32 line of Chinese hamster fibroblasts, we showed that GSH starvation produced by exposing cells to buthionine sulfoximine (BSO) increased the toxicity of chlorambucil and melphalan, but not that of N,N'-bis(2-chloroethyl)-N-nitrosourea (BCNU), cisplatine and doxorubicin. This indicates that efficient mechanisms of detoxification using GSH operate for chlorambucil and melphalan, but not for the other drugs in these cells. We then showed that GSH depletion could be selectively and transiently induced in the mu GST overexpressing cell line derived from GMA32, HC474, by exposing cells to substrates specific to the overexpressed isozyme. Exposing cells to such a substrate, trans-stilbene oxide, does not alter the sensibility of GMA32 cells to melphalan and chlorambucil, but increases that of HC474 cells to these drugs, to an extent comparable to that obtained with BSO. This observation highlights the possibility of exploiting GST overexpression, a frequent feature of tumor cells, to selectively sensitize these undesirable cells to anticancer drugs.
Insights
Glutathione (GSH) depletion enhances anticancer drug toxicity in cancer cells. Targeting glutathione S-transferases (GST) overexpression offers a strategy to selectively sensitize tumor cells to chemotherapy.
Area of Science:
- Biochemistry
- Pharmacology
- Oncology
Background:
- Glutathione (GSH) and glutathione S-transferases (GST) play a role in anticancer drug detoxification.
- Tumor cells often exhibit overexpression of GST enzymes.
- Understanding drug-GSH-GST interactions is crucial for improving cancer therapy.
Purpose of the Study:
- To investigate the role of GSH in the detoxification of various anticancer drugs.
- To explore the potential of targeting GST overexpression for selective cancer cell sensitization.
Main Methods:
- Used buthionine sulfoximine (BSO) to induce GSH starvation in Chinese hamster fibroblasts (GMA32).
- Assessed the toxicity of chlorambucil, melphalan, BCNU, cisplatin, and doxorubicin in GSH-starved cells.
- Induced selective GSH depletion in mu GST-overexpressing cells (HC474) using trans-stilbene oxide.
Main Results:
- GSH starvation increased the toxicity of chlorambucil and melphalan, but not BCNU, cisplatin, or doxorubicin in GMA32 cells.
- Selective GSH depletion in HC474 cells using trans-stilbene oxide enhanced their sensitivity to melphalan and chlorambucil.
- This sensitization effect in HC474 cells was comparable to that achieved with BSO.
Conclusions:
- GSH-mediated detoxification mechanisms are specific to certain anticancer drugs like chlorambucil and melphalan.
- Exploiting GST overexpression in tumor cells offers a potential strategy for selective sensitization to chemotherapy.
- Targeting GSH-GST pathways could lead to more effective and targeted cancer treatments.