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Research: KARAS and colleagues, De
Listed in Issue 58
Abstract
KARAS and colleagues, Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of Negev, Beer-Sheva, Israel. Yoav@bgumail.bgu.ac.il described how lycopene interferes with cell cycle progression and insulin-like growth factor I signalling in breast cancer cells.
Background
Recent studies have shown that high insulin-like growth factor I (IGF-I) blood level is a risk factor in breast and prostate cancer. In this study the authors aimed to determine whether the mitogenic activity of IGF-1 in breast cancer cells can be reduced by the dietary carotenoid lycopene. The anticancer activity of lycopene, the major tomato carotenoid has been suggested by in vitro, in vivo and epidemiological studies
Methodology
Results
Growth stimulation of MCF7 breast cancer cells by IGF-I was markedly reduced by physiological concentrations of lycopene. The inhibitory effect of lycopene on MCF7 cell growth were not accompanied by apoptotic or necrotic cell death. Lyopene treatment markedly reduced the IGF-I stimulation of tyrosine phosphorylation of insulin receptor substrate 1 and binding capacity of the AP-1 transcription complex. These effects were not associated with changes in the number or affinity of IGF-I receptors but with an increase in membrane associated IGF-I binding proteins, which were previously shown in different cancer cells to negatively regulate IGF-I receptor activation. The inhibitory effect of lycopene on IGF signalling was associated with suppression of IGF-stimulated cell cycle progression of serum-starved synchronized cells. Moreover, in cells synchronised by mimosine treatment, lycopene delayed cell cycle progression after release from the mimosine block.
Conclusion
The authors conclude that these data suggest that the inhibitory effects of lycopene on MCF7 cell growth are not due to the toxicity of the carotenoid but rather to interference in IGF-I receptor signalling and cell cycle progression.
References
Karas M et al. Lycopene interferes with cell cycle progression and insulin-like growth factor I signalling in mammary cancer cells. Nutrition in Cancer 36(1): 101-11. 2000.
