Roles of Reactive Oxygen Species in Biological Behaviors of Prostate Cancer

Table 1

Clinical studies conducted the chemoprevention of PCa by the antioxidants.

No.	Antioxidants	Mechanism	Major outcome	References
1	A–tocopherol	The downregulation of PSA levels	A–tocopherol slowed the progression of PCa patients with biochemical recurrence; Higher serum a-tocopherol at baseline improved PCa survival	[228]
2	A-carotene	A-carotene negatively regulate percent free PSA level, but not total PSA	A–carotene conferred a favorable prognosis after PCa recurrence.	[229]
3	Lycopene	Significant declines in serum PSA and markers of oxidative DNA damage; Prolongation of PSA doubting time	Lycopene was associated with a reduced risk of lethal PCa and enhanced the efficiency of radical prostatectomy.	[230, 231]
4	Vitamin D	Vitamin D slowed the rate of PSA increase	Vitamin D was beneficial to patients with asymptomatic progressive PCa; Vitamin D improved response rate and increased median survival time in patients taking docetaxel therapy.	[232, 233]
5	Selenium	Selenium regulated GPX1 to reduce lipid and hydrogen peroxides to water.	Selenium reduced PCa susceptibility and the risk of aggressive PCa.	[234–236]
6	Zinc	Inhibitions of metallothionein and NOX expression; Zinc served as a cofactor for the SOD enzyme.	Zinc improved survival only in men with early-stage cancers; Zinc modestly reduced the risk of high-grade disease	[237, 238]
7	Soy isoflavones	Soy isoflavones inhibited NF-κB and HIF-1α up-regulated by radiotherapy.	Soy isoflavones sensitized PCa patients to the radiotherapy and mitigated normal tissue injury.	[239, 240]
8	Green tea catechins	The electron delocalization and free radical scavenging	Green tea catechins served as secondary chemoprevention of PCa and reduced PCa incidences of men diagnosed with HG-PIN.	[241, 242]
9	Resveratrol	Resveratrol diminished NOX activity and increased the expression of CAT and glutathione reductase; Resveratrol prolonged the doubling time for PSA.	Resveratrol decreased the risk of PCa in men with the SOD2 Ala/Ala genotype.	[243]

Abbreviations: PSA: prostate-specific antigen; GPX 1: glutathione peroxidase 1; NOX: NADPH oxidase; SOD: superoxide dismutase; NF-κB: nuclear factor kappa-B; HIF-1α: hypoxia inducible factor-1α; HG-PIN: high-grade prostatic intraepithelial neoplasia; CAT: catalase.