CIRCADIAN RHYTHM OF PROLIFERATION IN INTESTINAL EPITHELIUM AND MAMMARY TUMORS IN HER-2/NEU TRANSGENIC AND FVB/N WILD TYPE MICE; THEIR CORRECTION WITH MELATONIN

Circadian rhythms and tumor development are interconnected as the factors like light pollution which disrupt circadian rhythms increase the risk of cancer, and oncological diseases are associated with changes in organism’s circadian rhythms. Circadian changes in intestinal epithelium and mammary tumors proliferation and apoptosis in HER-2/neu overexpressing FVB/N mice and assessment of melatonin’s influence on these parameters were studied in this work. It was shown by us that intestinal epithelium in mice exhibits circadian rhythm of proliferation with the peak in the morning and in tumor-bearing mice this rhythm is disrupted. Exogenous melatonin contributes to circadian rhythm of intestinal epithelium proliferation. Circadian changes in mammary tumors proliferation rate depend on melatonin secretion or supplementation time. Thus, melatonin may be considered as a perspective drug in anticancer therapy modulating circadian rhythms in cancerous and normal tissues.