Breast cancer oxidative stress

Another peculiarity of the study is that the use of a biological system has allowed the authors to hypothesize a possible mechanism of action of the leachate as a mixture, hypothesis that could have been drafted on the basis of the only knowledge derived by chemical analysis. Researchers suggest that leachate inhibits cell proliferation at low doses probably inducing a reversible cell cycle arrest that becomes irreversible at high doses, probably due to leachate-induced oxidative stress. This activity is mainly due to the chemical compounds extracted in the aqueous phase. Similar effects were noticed by previous investigations on other human cells (human peripheral blood lymphocytes and a human breast cancer cell line, MCF-7) [31, 32], supporting the hypothesis that cells that survive the initial insult from leachate constituents maintains the potential to proliferate until the effects on cell metabolism lead to death. 

It has been suggested that tamoxifen, one of the most effective therapeutic and chemopreventive agent for breast cancer, modulates protein kinase C through oxidative stress in breast cancer cells [194], Unfortunately, most breast cancers initially responsive to tamoxifen treatment later become resistant. Schiff et al. [195] suggested that the conversion of breast tumors to a tamoxifen-resistant phenotype is associated with oxidative stress and depends on significantly enhanced SOD activity in tumors. 

H.J. Knowles, A.L. Harris, Hypoxia and oxidative stress In breast cancer. Hypoxia and tumourigenesis. [Review], Breast Cancer Res. 3 (2001) 318-322. 

In addition to Keshan disease, a dilative cardiomyopathy first described in the Keshan Province of China, Se deficiency has been associated with an increase in various malignant diseases. Thus, well over 50 studies have demonstrated significant reductions in experimental cancer in laboratory animals supplemented with Se. Moreover, reports from Finland and the United States support the hypothesis that Se deficiency results in decreased cellular GPx activity, increases oxidative stress, and increases the incidence of cancer, particularly carcinoma of the breast, prostate, and colon (K13). 

The exact mechanism of anticancer effects of CLA is not clear, and several possible mechanisms could underlie the anticancer properties of CLA. These actions may include its ability to interfere with the proliferation of cancer cells, increased apoptotic cell death, inhibition of angiogenesis, or increased oxidative stress. In a study comparing the effects of CLA on estrogen receptor positive human breast cancer cells (MCF-7) and estrogen receptor negative (MDA-MB 231) cells, CLA was shown to selectively inhibit proliferation of estrogen receptor positive cells. 

Glucose deprivation has been shown to cause activation of Lyn kinase, c-Jun W-terminal kinase 1 and to increase the expression of basic fibroblast growth factor and c-Myc in adri-amycin-resistant human breast cancer cells. Thus, glucose oxidation may be linked to cellular oxidative stress as evidenced from increase in the steady state of oxidized glutathione and intracellular peroxides [85]. A unique glucose-dependent apoptotic pathway is induced by the cellular oncogen c-Myc in transformed fibroblasts [86]. 

Oakley GG, Devanaboyina U, Robertson LW, et al. 1996. Oxidative DNA damage induced by activation of polychlorinated biphenyls (PCBs) Implications for PCB-induced oxidative stress in breast cancer. Chem Res Toxicol 9 1285-1292. 

Elevated use of extra-virgin olive oils, which are particularly rich in these phenolic antioxidants, as well as squalene, oleic and other unsaturated acids, should afford significant protection against cancer (colon, skin, breast), coronary heart disease and ageing by inhibiting oxidative stress [44],... 

Probably olive oil components may reduce oxidative stress via inhibition of lipid peroxidation, an interesting mechanism responsible for diseases such as cancer, heart ailment and ageing. The soluble fat should have chemopreventive effects against breast cancer and other diseases. 

Chen G, Djuric Z. Detection of 2, 6-cyclolycopene-l, 5-diol in breast nipple aspirate fluids and plasma a potential marker of oxidative stress. Cancer Epidemiol Biomarkers Prev 2002 11 1592-1596. 

Although the etiology of breast cancer is multifactorial with genetic and hormonal influences, increased oxidative stress may also contribute to breast cancer risk in susceptible individuals. However, none of the seven prospective studies that assessed... 

Castro, G. D de-Castro, C. R. Maciel, M. E FaneUi, S. L de-Ferreyra, E. C. Gomez, M. I. D. Castro, J. A. Ethanol-induced oxidative stress and acetaldehyde formation in rat mammary tissue potential factors involved in alcohol drinking promotion of breast cancer. Toxicology 2006, 219, 208-219. 

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