Abstract
This study aims to investigate the role of γ-glutamylcysteine synthetase (γ-GCS), the rate-limiting enzyme for glutathione (GSH) synthesis, in the c-Myc-dependent response to antineoplastic agents. We found that specific c-Myc inhibition depleted cells of GSH by directly reducing the gene expression of both heavy and light subunits of the γ-GCS enzyme and increased their susceptibility to antineoplastic drugs with different mechanisms of action, such as cisplatin (CDDP), staurosporine (STR), and 5-fluorouracil (5-FU). The effect caused by c-Myc inhibition on CDDP and STR response, but not to 5-FU treatment, is directly linked to the impairment of the γ-GCS expression, because up-regulation of γ-GCS reverted drug sensitivity, whereas the interference of GSH synthesis increased drug susceptibility as much as after c-Myc down-regulation. The role of γ-GCS in the c-Myc-directed drug response depends on the capacity of drugs to trigger reactive oxygen species (ROS) production. Indeed, although 5-FU exposure did not induce any ROS, CDDP- and STR-induced oxidative stress enhanced the recruitment of c-Myc on both γ-GCS promoters, thus stimulating GSH neosynthesis and allowing cells to recover from ROSinduced drug damage. In conclusion, our data demonstrate that the γ-GCS gene is the downstream target of c-Myc oncoprotein, driving the response to ROS-inducing drugs. Thus, γ-GCS impairment might specifically sensitize high c-Myc tumor cells to chemotherapy.
| Original language | English |
|---|---|
| Pages (from-to) | 1015-1023 |
| Number of pages | 9 |
| Journal | Molecular Pharmacology |
| Volume | 72 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Oct 2007 |
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ASJC Scopus subject areas
- Pharmacology
Cite this
γ-Glutamylcysteine synthetase mediates the c-Myc-dependent response to antineoplastic agents in melanoma cells. / Benassi, Barbara; Zupi, Gabriella; Biroccio, Annamaria.
In: Molecular Pharmacology, Vol. 72, No. 4, 10.2007, p. 1015-1023.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - γ-Glutamylcysteine synthetase mediates the c-Myc-dependent response to antineoplastic agents in melanoma cells
AU - Benassi, Barbara
AU - Zupi, Gabriella
AU - Biroccio, Annamaria
PY - 2007/10
Y1 - 2007/10
N2 - This study aims to investigate the role of γ-glutamylcysteine synthetase (γ-GCS), the rate-limiting enzyme for glutathione (GSH) synthesis, in the c-Myc-dependent response to antineoplastic agents. We found that specific c-Myc inhibition depleted cells of GSH by directly reducing the gene expression of both heavy and light subunits of the γ-GCS enzyme and increased their susceptibility to antineoplastic drugs with different mechanisms of action, such as cisplatin (CDDP), staurosporine (STR), and 5-fluorouracil (5-FU). The effect caused by c-Myc inhibition on CDDP and STR response, but not to 5-FU treatment, is directly linked to the impairment of the γ-GCS expression, because up-regulation of γ-GCS reverted drug sensitivity, whereas the interference of GSH synthesis increased drug susceptibility as much as after c-Myc down-regulation. The role of γ-GCS in the c-Myc-directed drug response depends on the capacity of drugs to trigger reactive oxygen species (ROS) production. Indeed, although 5-FU exposure did not induce any ROS, CDDP- and STR-induced oxidative stress enhanced the recruitment of c-Myc on both γ-GCS promoters, thus stimulating GSH neosynthesis and allowing cells to recover from ROSinduced drug damage. In conclusion, our data demonstrate that the γ-GCS gene is the downstream target of c-Myc oncoprotein, driving the response to ROS-inducing drugs. Thus, γ-GCS impairment might specifically sensitize high c-Myc tumor cells to chemotherapy.
AB - This study aims to investigate the role of γ-glutamylcysteine synthetase (γ-GCS), the rate-limiting enzyme for glutathione (GSH) synthesis, in the c-Myc-dependent response to antineoplastic agents. We found that specific c-Myc inhibition depleted cells of GSH by directly reducing the gene expression of both heavy and light subunits of the γ-GCS enzyme and increased their susceptibility to antineoplastic drugs with different mechanisms of action, such as cisplatin (CDDP), staurosporine (STR), and 5-fluorouracil (5-FU). The effect caused by c-Myc inhibition on CDDP and STR response, but not to 5-FU treatment, is directly linked to the impairment of the γ-GCS expression, because up-regulation of γ-GCS reverted drug sensitivity, whereas the interference of GSH synthesis increased drug susceptibility as much as after c-Myc down-regulation. The role of γ-GCS in the c-Myc-directed drug response depends on the capacity of drugs to trigger reactive oxygen species (ROS) production. Indeed, although 5-FU exposure did not induce any ROS, CDDP- and STR-induced oxidative stress enhanced the recruitment of c-Myc on both γ-GCS promoters, thus stimulating GSH neosynthesis and allowing cells to recover from ROSinduced drug damage. In conclusion, our data demonstrate that the γ-GCS gene is the downstream target of c-Myc oncoprotein, driving the response to ROS-inducing drugs. Thus, γ-GCS impairment might specifically sensitize high c-Myc tumor cells to chemotherapy.
UR - http://www.scopus.com/inward/record.url?scp=34748871336&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34748871336&partnerID=8YFLogxK
U2 - 10.1124/mol.107.038687
DO - 10.1124/mol.107.038687
M3 - Article
C2 - 17628013
AN - SCOPUS:34748871336
VL - 72
SP - 1015
EP - 1023
JO - Molecular Pharmacology
JF - Molecular Pharmacology
SN - 0026-895X
IS - 4
ER -