The Chemoprotective Agent N-Acetylcysteine Blocks Cisplatin-Induced Apoptosis through Caspase Signaling Pathway

Abstract

Thiols such as N-acetylcysteine (NAC) are increasingly used in clinical trials of platinum chemotherapy as chemoprotectants. NAC can prevent cisdiamminedichloroplatinum (cisplatin)-induced ototoxicity, nephrotoxicity, and gastrointestinal toxicity; however, the molecular mechanisms of NAC on apoptosis and cisplatin cytotoxicity remain unknown. We investigated cisplatin cytotoxicity and NAC chemoprotection in human tumor cell lines, as assessed by immunoblotting and immunocytochemistry. Cisplatin cytotoxicity was associated with nuclear translocation of apoptosis induction factor, expression of the pro-apoptotic Bax protein, cleavage of caspases 3 and 9, and cleavage of PARP. NAC administration reversed the cytotoxic and apoptotic effects if added concurrent with cisplatin or up to 2 h after cisplatin, but chemoprotection was reduced if NAC administration was delayed more than 2 h and was minimal by 8 h after cisplatin. Expression of tumor suppressor p53 and the cell cycle regulatory protein p21 was stimulated within 5 to 10 min by cisplatin in p53-positive LX-1 small cell lung carcinoma cells, and this effect was blocked by NAC. In p53-negative SKOV3 cells, cisplatin toxicity and NAC chemoprotection remained effective, suggesting that chemoprotection may be mediated through both p53-dependent and -independent pathways. Specific kinase inhibitors demonstrated that cisplatin induced apoptosis through the p38 mitogen-activated protein kinase (MAPK) pathway, not the extracellular signal-regulated kinase MAPK pathway. These results show that NAC blocks both the death receptor and the mitochondrial apoptotic pathways induced by cisplatin. The time course for NAC chemoprotection after cisplatin matches our previous in vivo results and provides an opportunity to manipulate route and timing to maintain cisplatin antitumor efficacy while protecting against chemotherapy side effects.

The mode of cisplatin-induced cell death in CYP2E1-overexpressing HepG2 cells: Modulation by ERK, ROS, glutathione, and thioredoxin

“…Cisplatin induces activation of MAPK such as P38 MAPK, JNK, and ERK in different cell models (17)(18)(19)(20). In E47 cells, cisplatin induced ERK activation but not activation of P38 MAPK and JNK.…”

“…Cisplatin-induced apoptosis is caspase-dependent (20,35). Therefore, activities of caspase-3, -8 and -9 were determined in the absence and presence of BSO and/or U0126.…”

Protective effect of selenium on cisplatin induced nephrotoxicity: A double-blind controlled randomized clinical trial

“…Selenium is an effective agent on glutathione peroxidases enzyme system that protects intracellular structures from oxidative stresses. Moreover, as being a moiety of thioreduxin reductase, it maintains antioxidant activity of vitamin C. As well, it supports vitamin E function for limitation of lipid oxidation (9)(10)(11)(12)(13).…”

“…Up to now, some methods have been applied to prevent or attenuate cisplatin nephrotoxicity including; saline infusion, osmotic diuresis, low dose and slow rate of cisplatin injection and co-administration of magnesium sulphate or hydroxide, amifostin, thiosulfate, N-acetyl cysteine, theophylline and glycine (4)(5)(6)(7)(8)(9)(10)(11)(12). Except for saline infusion, none of these methods has been proved to be effective (5,6,13).…”

Thiol-reducing agents prevent sulforaphane-induced growth inhibition in ovarian cancer cells

“…The use of NAC has been reported to increase tumor growth in animal models [45] and to alter the efficacy of cancer therapy [46]. NAC was shown to be independently associated with worse recurrence-free and overall survival in breast cancer patients who received NAC as an adjuvant chemotherapy [47].…”