Disulfiram promotes the conversion of carcinogenic cadmium to a proteasome inhibitor with pro-apoptotic activity in human cancer cells

Journal Article · Sun Jun 01 04:00:00 EDT 2008 · Toxicology and Applied Pharmacology

OSTI ID:21140854

Lihua, Li ^[1]; Huanjie, Yang; Di, Chen; Cui, Cindy ^[1]

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1. Prevention Program, Barbara Ann Karmanos Cancer Institute, and Department of Pathology, School of Medicine, Wayne State University, Detroit, Michigan 48201 (United States)

The ubiquitin-proteasome system is involved in various cellular processes, including transcription, apoptosis, and cell cycle. In vitro, in vivo, and clinical studies suggest the potential use of proteasome inhibitors as anticancer drugs. Cadmium (Cd) is a widespread environmental pollutant that has been classified as a human carcinogen. Recent study in our laboratory suggested that the clinically used anti-alcoholism drug disulfiram (DSF) could form a complex with tumor cellular copper, resulting in inhibition of the proteasomal chymotrypsin-like activity and induction of cancer cell apoptosis. In the current study, we report, for the first time, that DSF is able to convert the carcinogen Cd to a proteasome-inhibitor and cancer cell apoptosis inducer. Although the DSF-Cd complex inhibited the chymotrypsin-like activity of a purified 20S proteasome with an IC{sub 50} value of 32 {mu}mol/L, this complex was much more potent in inhibiting the chymotrypsin-like activity of prostate cancer cellular 26S proteasome. Inhibition of cellular proteasome activity by the DSF-Cd complex resulted in the accumulation of ubiquitinated proteins and the natural proteasome substrate p27, which was followed by activation of calpain and induction of apoptosis. Importantly, human breast cancer MCF10DCIS cells were much more sensitive to the DSF-Cd treatment than immortalized but non-tumorigenic human breast MCF-10A cells, demonstrating that the DSF-Cd complex could selectively induce proteasome inhibition and apoptosis in human tumor cells. Our work suggests the potential use of DSF for treatment of cells with accumulated levels of carcinogen Cd.

• OSTI ID: 21140854
• Journal Information: Toxicology and Applied Pharmacology, Journal Name: Toxicology and Applied Pharmacology Journal Issue: 2 Vol. 229; ISSN TXAPA9; ISSN 0041-008X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ANTINEOPLASTIC DRUGS
APOPTOSIS
CADMIUM
CARCINOGENS
CELL CYCLE
CHYMOTRYPSIN
IN VITRO
IN VIVO
INHIBITION
MAMMARY GLANDS
NEOPLASMS
POLLUTANTS
PROSTATE
SUBSTRATES
TRANSCRIPTION
TUMOR CELLS