Adrenal cortisol-producing tumors can express illicit membrane receptors such as luteinizing hormone (LH), glucose-dependent insulinotropic peptide (GIP) or type 4 and 7 serotonin (5-HT4/7) receptors. Abnormal expression of the LH receptor (LH-R) has been ascribed to activation of the Wnt/β-catenin signaling pathway in adrenocortical cells. In the present study, we have investigated whether β-catenin activation may also trigger illegitimate expression of GIP and 5-HT receptors. Three models of β-catenin activation in adrenocortical cells were used: an APC-mutated adrenocortical tumor, human transfected adrenocortical cells and genetically modified mouse adrenal glands. The methods employed included RT-qPCR, immunohistochemistry, and measurement of cortisol secretion by cultured tumor cells. Abnormal expression of the GIP, 5-HT7 and LH receptors was observed in the APC-mutated adrenocortical tumor tissue. In addition, GIP, 5-HT and hCG stimulated cortisol production from tumor cells in primary culture. Conversely, only the LHCGR was upregulated in human and mouse adrenocortical cells harboring activation of β-catenin. Moreover, LH-R immunoreactivity was detected in clusters of zona fasciculata cells in the β-catenin-activated mouse model. Our data indicate that activation of the β-catenin signaling pathway can promote illicit expression of functional LH receptors in adrenal zona fasciculata cells but does not favor abnormal expression of GIP and 5-HT receptors.
Developmental exposure to endocrine disrupter dichlorodiphenyltrichloroethane alters transcriptional regulation of postnatal morphogenesis of adrenal zona fasciculata
