FGF-1 modulates pancreatic ß-cell functions/metabolism: An in vitro study.

Fibroblast growth factor 1 (FGF-1), also known as acidic fibroblast growth factor (aFGF), is a growth factor and signaling protein encoded by the Fgf1 gene. Previous studies have shown that FGF-1 may also participate in the regulation of glucose metabolism, both in healthy organisms and in pathological conditions such as diabetes. Because insulin the main regulator of glucose metabolism is secreted from pancreatic beta cells, we investigated whether FGF-1 directly affects the secretion of this hormone and regulates the metabolism of beta cells and isolated pancreatic islets. By using insulin-producing INS-1E cells and isolated pancreatic islets, we investigated the effect of FGF-1 on cell proliferation, viability, apoptosis, and insulin expression and secretion. Our study showed that FGF1 and fibroblast growth factor receptors (FgfRs: FgfR1, FgfR2, FgfR3, and FgfR4) are present on mRNA level in INS-1E cells and isolated rat pancreatic islets. We also proved that FGF1 stimulates the proliferation of INS-1E beta cells and enhances the viability of these cells and that of isolated pancreatic islet cells, and that ERK1/2 kinase is involved in the regulation of INS-1E cell proliferation. Moreover, we found that FGF1 can stimulate insulin secretion from both INS-1E cells and isolated rat pancreatic islets. Thus, the FGF1 peptide increases cell survival and decreases cell death. The obtained results indicate that FGF1 may play a role in controlling the physiology and metabolism of pancreatic beta cells as well as glycemia.

Biological response of adrenal carcinoma and melanoma cells to mitotane treatment.

A previous case report described an adrenal incidentaloma initially misdiagnosed as adrenocortical carcinoma (ACC), which was treated with mitotane. The final diagnosis was metastatic melanoma of unknown primary origin. However, the patient developed rapid disease progression after mitotane withdrawal, suggesting a protective role for mitotane in a non-adrenal-derived tumor. The aim of the present study was to determine the biological response of primary melanoma cells obtained from that patient, and that of other established melanoma and ACC cell lines, to mitotane treatment using a proliferation assay, flow cytometry, quantitative PCR and microarrays. Although mitotane inhibited the proliferation of both ACC and melanoma cells, its role in melanoma treatment appears to be limited. Flow cytometry analysis and transcriptomic studies indicated that the ACC cell line was highly responsive to mitotane treatment, while the primary melanoma cells showed a moderate response in vitro. Mitotane modified the activity of several key biological processes, including 'mitotic nuclear division', 'DNA repair', 'angiogenesis' and 'negative regulation of ERK1 and ERK2 cascade'. Mitotane administration led to elevated levels of DNA double-strand breaks, necrosis and apoptosis. The present study provides a comprehensive insight into the biological response of mitotane-treated cells at the molecular level. Notably, the present findings offer new knowledge on the effects of mitotane on ACC and melanoma cells.

Adropin Stimulates Proliferation and Inhibits Adrenocortical Steroidogenesis in the Human Adrenal Carcinoma (HAC15) Cell Line.

Adropin is a multifunctional peptide hormone encoded by the ENHO (energy homeostasis associated) gene. It plays a role in mechanisms related to increased adiposity, insulin resistance, as well as glucose, and lipid metabolism. The low adropin levels are strongly associated with obesity independent insulin resistance. On the other hand, overexpression or exogenous administration of adropin improves glucose homeostasis. The multidirectional, adropin-related effects associated with the regulation of metabolism in humans also appear to be attributable to the effects of this peptide on the activity of various elements of the endocrine system including adrenal cortex. Therefore, the main purpose of the present study was to investigate the effect of adropin on proliferation and secretory activity in the human HAC15 adrenal carcinoma cell line. In this study, we obtained several highly interesting findings. First, GPR19, the main candidate sensitizer of adrenocortical cells to adropin, was expressed in HAC15 cells. Moreover, GPR19 expression was relatively stable and not regulated by ACTH, forskolin, or adropin itself. Our findings also suggest that adropin has the capacity to decrease expression levels of steroidogenic genes such as steroidogenic acute regulatory protein (StAR) and CYP11A1, which then led to a statistically significant inhibition in cortisol and aldosterone biosynthesis and secretion. Based on whole transcriptome study and research involving transforming growth factor (TGF)-ß type I receptor kinase inhibitor we demonstrated that attenuation of steroidogenesis caused by adropin is mediated by the TGF-ß signaling pathway likely to act through transactivation mechanism. We found that HAC15 cells treated with adropin presented significantly higher proliferation levels than untreated cells. Using specific intracellular inhibitors, we showed that adropin stimulate proliferation via ERK1/2 and AKT dependent signaling pathways. We have also demonstrated that expression of GPR19 is elevated in adrenocortical carcinoma in relation to normal adrenal glands. High level of GPR19 expression in adrenocortical carcinoma may constitute a negative prognostic factor of disease progression.