Vitamin C and alpha-naphthoflavone prevent estrogen-induced mammary tumors and decrease oxidative stress in female...

Area of Science:

• Oncology
• Endocrinology
• Biochemistry

Background:

• The precise mechanisms driving estrogen-induced breast carcinogenesis are not fully understood.
• Estrogen metabolism and oxidative stress are implicated in mammary tumor development.
• Investigating preventative strategies is crucial for understanding and combating breast cancer.

Purpose of the Study:

• To investigate the roles of estrogen metabolism and oxidative stress in estrogen-mediated mammary carcinogenesis in vivo.
• To evaluate the efficacy of antioxidant vitamin C and estrogen metabolic inhibitor alpha-naphthoflavone (ANF) in preventing estrogen-induced breast cancer.

Main Methods:

• Female August Copenhagen Irish (ACI) rats were administered 17beta-estradiol (E(2)) with or without vitamin C or ANF for up to 8 months.
• Tumor incidence, oxidative stress markers (8-iso-prostane F(2alpha), superoxide dismutase, glutathione peroxidase), and estrogen metabolite formation (2-OHE(2), 4-OHE(2)) were assessed.
• ANF's effect on E(2) hydroxylation, specifically 4-hydroxylation, was quantified.

Main Results:

• Breast tumor incidence was 82% in the E(2) group, 29% in the E(2) + vitamin C group, and 0% in the E(2) + ANF group.
• Vitamin C and ANF attenuated E(2)-induced oxidative stress markers in breast tissue.
• ANF inhibited 4-hydroxylation of E(2), reducing the formation of carcinogenic 4-OHE(2).

Conclusions:

• Antioxidant vitamin C reduces the incidence and increases the latency of estrogen-induced mammary tumors, decreasing oxidative stress.
• Alpha-naphthoflavone (ANF) completely abrogates estrogen-induced breast cancer development in this animal model.
• Estrogen metabolism and oxidative stress are critical factors in estrogen-induced breast carcinogenesis, offering potential therapeutic targets.