Bucillamine induces glutathione biosynthesis via activation of the transcription factor Nrf2.

Abstract

The properties of bucillamine, a synthetic antioxidant, have been attributed mainly to the donation of thiol groups to glutathione (GSH). We recently demonstrated that glutamate-cysteine ligase catalytic subunit (GCLC), the rate-limiting enzyme of GSH biosynthesis, and the multidrug-resistance-associated protein 2 (Mrp2/MRP2) are coordinately induced in response to xenobiotic through the activation of the antioxidant-response element (ARE) by nuclear factor-erythroid 2 p45-related factor (Nrf2). We tested the hypothesis that bucillamine and its oxidized metabolite SA 981 also activate the Nrf2 pathway, thereby increasing glutathione biosynthesis in human HepG2 and murine Hepa 1-6 hepatoma cell lines, through the induction of the GCLC enzyme as well as the Mrp2/MRP2 transporter, which mediates the excretion of glutathione and its conjugates from hepatocytes. Both bucillamine and SA 981 produced a significant dose-dependent increase in the mRNA levels of Mrp2/MRP2 and GCLC after 24 h. The levels of the transcription factor Nrf2 in the nuclei were maximal at 3 h, remained elevated at 6 h, and decreased to control values at 24 h in both cell lines. Moreover, both bucillamine and SA 981 significantly increased the expressions of Mrp2/MRP2 and GCLC proteins in both cell lines. Finally, in both cell lines, bucillamine and SA 981 increased the GSH content two- to three-fold. These results demonstrate that bucillamine and SA 981 activate the ARE-ARE pathway increasing the expression of ARE-driven genes such as those of GCLC and Mrp2/MRP2. The role of bucillamine as a chemopreventive agent against cancer remains to be elucidated.

• Authors: Ana M Wielandt, Valeska Vollrath, Marcelo Farias, Jose Chianale
• Journal: Biochemical pharmacology (Biochem Pharmacol) Vol. 72 Issue 4 Pg. 455-62 (Aug 14 2006) ISSN: 0006-2952 [Print] England
• PMID: 16806086 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• ABCC2 protein, human
• Membrane Transport Proteins
• Multidrug Resistance-Associated Protein 2
• Multidrug Resistance-Associated Proteins
• NF-E2 Transcription Factor, p45 Subunit
• RNA, Messenger
• bucillamine disulfide
• Glutamate-Cysteine Ligase
• Glutathione
• Cysteine
• bucillamine

Topics

• Active Transport, Cell Nucleus (drug effects)
• Animals
• Blotting, Northern
• Blotting, Western
• Carcinoma, Hepatocellular (genetics, metabolism, pathology)
• Catalytic Domain (genetics)
• Cell Line, Tumor
• Cell Nucleus (drug effects, metabolism)
• Cysteine (analogs & derivatives, chemistry, pharmacology)
• Gene Expression (drug effects, genetics)
• Glutamate-Cysteine Ligase (genetics, metabolism)
• Glutathione (biosynthesis)
• Humans
• Membrane Transport Proteins (genetics, metabolism)
• Molecular Structure
• Multidrug Resistance-Associated Protein 2
• Multidrug Resistance-Associated Proteins (genetics, metabolism)
• NF-E2 Transcription Factor, p45 Subunit (genetics, metabolism)
• RNA, Messenger (genetics, metabolism)