Chronobiological features of melatonin receptors (MT1) expression in breast cancer cells.

Abstract

e12581 Background: According to WHO data, Breast Cancer is the most prevalent malignancy in women. The biological role of Melatonin in the etiology and pathogenesis of the tumour disease has already been approved by a number of research studies. The purpose of our investigation was the assessment of features of Melatonin receptor circadian expression in circulating tumour cells of breast cancer (CTCs). Methods: We observed 34 patients (aged 36-68) with breast cancer (various immunophenotypes). CTCs were separated from patients’ venous blood every third day, in 02:00-04:00 pm and in 02:00-04:00 am intervals. The cells were taken from each patient 4 times. On CTCs, MT1 – receptor expression was assessed using immunocytochemical method. Results: Results of the study revealed that Melatonin receptor expression in breast cancer patients is characterised by the noticable circadian rhythmics. MT1–receptor expression peak by CTCs was detected at 02:00-04:00 am i.e. at night. The less aggressive tumor the higher is the extent of the receptor expression (density). Respectively, in hormone dependent and Her2/neu (negative) tumors the highest expression of the MT1–receptor occurs in hormone dependent and Her2/neu(positive) tumors–medium expression and in triple negative breast Cancer (TNBC) cells–the lowest expression, while in some TNBC–circulating tumor cells MT1 receptor expression has not been detected at all. Conclusions: Hence, based on our the results, we can conclude that Melatonin as the expression of main biochemical marker receptors of bio-rhythms in breast cancer cells, has highly expressed chronobiological nature and directly correlates with histological types of tumor, that provides conditions for the development of new chronotherapeutic strategies in breast cancer treatment.