Related Experiment Videos
Cancer prevention by antioxidants
Hoyoku Nishino1, Harukuni Tokuda, Yoshiko Satomi
1Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan. hnishino@basic.kpu-m.ac.jp
Biofactors (Oxford, England)
|January 5, 2005
Summary
Dietary antioxidants like carotenoids and flavonoids show promise in cancer prevention. Mixtures of these compounds, particularly carotenoids, significantly suppressed liver cancer development and skin tumor initiation by inhibiting nitric oxide synthase induction.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- Antioxidants in food, including phenolic compounds and carotenoids, exhibit anticarcinogenic properties.
- Nitric oxide (NO) plays a role in carcinogenesis, with elevated levels and inducible NO synthase (iNOS) expression linked to tumor growth and metastasis.
- Peroxynitrite, a reactive NO metabolite, may mediate some of NO's pathological effects.
Purpose of the Study:
- To investigate the tumor-initiating activity of peroxynitrite.
- To evaluate the anti-tumor effects of natural antioxidants, specifically curcumin and nobiletin.
- To explore the impact of phytoene synthase gene expression on iNOS induction.
Main Methods:
- Assessing tumor initiation using peroxynitrite (initiator) and TPA (promoter) in mouse skin models.
- Administering natural antioxidants like curcumin and nobiletin to evaluate their inhibitory effects.
- Analyzing iNOS induction in both control and phytoene synthase transgenic mice after exposure to a lung tumor promoter.
Main Results:
- Peroxynitrite demonstrated tumor-initiating activity in conjunction with TPA.
- Curcumin and nobiletin exhibited anti-tumor initiating effects, with nobiletin also suppressing iNOS induction.
- Phytoene-producing mice showed lower iNOS gene induction in the lungs compared to controls after glycerol administration.
Conclusions:
- Combinations of dietary antioxidants, such as mixed carotenoids and flavonoids, represent a potentially effective strategy for cancer prevention.
- Targeting iNOS induction through antioxidant intervention may be a viable approach for cancer chemoprevention.
- Understanding the interplay between NO, peroxynitrite, and antioxidants is crucial for developing novel cancer prevention therapies.