Nampt (Visfatin) Influence on Proliferative Activity of Normal Rat Adrenocortical Cells and Human Adrenal Corticocarcinoma Nci-H295r Cells

Abstract

Nampt (Nicotinamidephosphoribosyltransferase - also known as visfatin/PBEF) is the enzyme that regulates the NAD+ level, therefore influencing many metabolic pathways within the cells. As circulating cytokine, extracellular Nampt (eNampt) exerts pro-inflammatory, pro-chemotactic, pro-angiogenic and insulin-like effects; however the mechanism of eNampt action is still unclear.Earlier studies have shown that eNampt exerts a stimulating effect on the proliferation of many cancer cell lines. However, the effect of this cytokine on cell proliferation in primary culture is little known. Therefore, the aim of the study was to analyse the influence of eNampt on the proliferation of rat adrenocortical cells in primary culture and to investigate similar influence of eNampt on the line H295R of human adrenal corticocarcinoma cells. Proliferation of the examined cells was assessed using the RTCA (Real Time Cell Analyzer) method. The obtained results indicate that eNampt stimulates the proliferation of H295R cells, but does not change the proliferation of cultured rat adrenocortical cells. In primary culture of rat adrenocortical cells, Fk866 (specific Nampt inhibitor) does not modify the rate of proliferation of tested cells. In H295R cells the addition of Fk866 alone inhibits proliferative activity and stimulates apoptosis. Fk866 also inhibits the stimulating effect of eNampt on H295R cell proliferation.

Extracellular Nampt (eNampt/Visfatin/PBEF) directly and indirectly stimulates ACTH and CCL2 protein secretion from isolated rat corticotropes

“…Differences in the effect of eNampt on normal and tumor cells were also observed in our previous studies. 38 In these studies, in primary culture, eNampt did not affect the rate of proliferation of rat adrenocortical cells, but it did stimulate proliferation of the H295R adrenocortical cancer cell line. It is difficult to explain the causes of the different effects of eNampt on normal and neoplastic cells.…”