In-vitro investigation of calcitonin associated effects on the trophoblastic cells

Calcitonin is expressed in the epithelium of endometrium, and modulates zonula adherens junctions which are composed of cadherin-catenins complex during the implantation window. Trophoblastic cells which have complex interaction with the epithelial cells of endometrium during implantation were demonstrated to have calcitonin receptors. Mechanism of action of calcitonin on trophoblastic cells has not yet been elucidated. Therefore, it was aimed to determine the effects of calcitonin on the expressions of β-catenin and phospho-β-catenin in a dose depended manner under the influence of progesterone and estrogen hormones (P + E) by using JAR cell line through the immunocytochemical and Western blot analyses. Moreover, adherens junctions (AJs) were ultrastructurally investigated to assess the involvement of cadherin-catenin complex in accordance with the changes in the specified parameters. Immunocytochemical analysis showed that only 10 nM calcitonin treated group had increased expression of membranous β-catenin compared to the control group, while there was decreased expression of β-catenin in the nucleus of all the experimental groups. Cytoplasmic expressions of the phospho-β-catenin decreased in all experimental groups compared to the control group while the decrease in the nuclear expression was remarkable in the groups treated with P + E, and P + E + 250 nM calcitonin. Western blot analysis showed that total β-catenin and phospho-β-catenin expressions were not significantly different. Ultrastructural analysis showed that increase in the number of AJs was noticeable in the group treated with 10 nM calcitonin. Overall, the localization and expression levels of β-catenin and phospho-β-catenin suggest that calcitonin could show its effects through the non-canonical pathway in the trophoblastic cells.