Growth and cell cycle regulation by isoflavones in human breast carcinoma cells

Abstract

antiestrogen-like activities [20,21]. In recent years, isoflavones have attracted much attention because of their possible cancer-preventing effects for certain cancers. It has been observed that Asian women who consume a traditional low-fat high-soy diet have a lower risk of developing breast cancer, INTRODUCTIONIsoflavones are a group of chemicals present in plants and foliage. The structural similarity of isoflavones to natural animal estrogens has suggested that this group of chemicals may exhibit certain estrogen-or Original articleGrowth and cell cycle regulation by isoflavones in human breast carcinoma cells Abstract -The isoflavones daidzein and biochanin A induced a biphasic growth response in T-47D human breast cancer cells. At growth stimulatory concentrations, daidzein increased the percentage of cells entering the S phase, while at a growth inhibitory concentration, daidzein obstructed the progression of the cell cycle in the G2/M phase. Biochanin A regulated the cell cycle progression in a similar manner and showed a delay in the progression from the S phase to the G2/M phase at growth inhibitory concentrations. The levels of a cell cycle regulatory protein, P53, in response to the treatment of isoflavones, were also determined. Cells that became de-attached and floated in the medium after treatment with growth inhibitory concentrations of daidzein or biochanin A, showed higher P53 levels than cells that remained attached. These results suggest that daidzein and biochanin A influence T-47D cell proliferation and cell cycle progression, and that the underlying mechanisms might be associated with the P53 protein levels.isoflavones / cell cycle / P53 / breast cancer cells Reprod. Nutr. Dev. 42 (2002) 55-64 55

Biochanin A Inhibits Breast Cancer Tumor Growth in A Murine Xenograft Model

“…These findings are different from in vitro studies where a similar concentration of BCA (330 or 500 nM) had no effect on the cellular proliferation of MCF-7 cells (15). The observed accumulation of BCA in tumor tissue may explain this discrepancy, because BCA can inhibit the growth of estrogen receptor (ER) positive cells at concentrations >20 μM through ER-independent mechanisms, while stimulating the growth at lower concentrations (22,23). Unfortunately we did not have sufficient tumor samples to measure BCA concentrations in tumor tissues.…”

Pharmacokinetics and bioavailability of the isoflavone biochanin A in rats

“…3 The biochemical and pharmacological properties of isofl avones that may be related to these health benefi ts are multifaceted and may involve isofl avones ' antioxidative, 4 antiestrogenic (as well as estrogenic), 5 and antiangiogenic activities, 6 as well as their inhibition of procarcinogen metabolic activation 7 and inhibition of cell growth. 8 The most studied isofl avone is genistein (GEN), a soy-derived isofl avone that has been shown to be an effective chemopreventive agent of chemicalinduced carcinogenesis in vivo. [9][10][11] GEN, together with other soy isofl avones, may also reduce the low-density lipoprotein (LDL) cholesterol level in animal models 12 , 13 and in premenopausal women, 14 and a cardiovascular health claim was approved by the US Food and Drug Administration in 1999 for foods with signifi cant amounts of soy protein.…”

Effects of Flavonoids Genistein and Biochanin A on Gene Expression and Their Metabolism in Human Mammary Cells

“…Popularly sold herbal supplements contain high amounts of BCA (5). The biological effects of BCA have been much less documented compared with those of GEN, but BCA also has cancer-preventive properties (6,7). Even though BCA is converted to GEN in vivo and in vitro, the growth-inhibitory effects of BCA are not identical to those of GEN (8,9).…”