POD-1 binding to the E-box sequence inhibits SF-1 and StAR expression in human adrenocortical tumor cells

Abstract

Pod-1/Tcf21 is expressed at epithelial-mesenchymal interaction sites during development of many organs. Different approaches have demonstrated that Pod-1 transcriptionally inhibits Sf-1/NR5A1 during gonadal development. Disruption of Sf-1 can lead to disorders of adrenal development, while increased dosage of SF-1 has been related to increased adrenal cell proliferation and tumorigenesis. In this study, we analyzed whether POD-1 overexpression inhibits the endogenous Sf-1 expression in human and mouse adrenocortical tumor cells. Cells were transiently transfected with luciferase reporter gene under the control of Sf-1 promoter and with an expression vector encoding Pod-1. Pod-1 construct inhibited the transcription of the Sf1/Luc reporter gene in a dose-dependent manner in mouse Y-1 adrenocortical carcinoma (ACC) cells, and inhibited endogenous SF-1 expression in the human H295R and ACC-T36 adrenocortical carcinoma cells. These results were validated by chromatin immunoprecipitation assay with POD-1-transfected H295R cells using primers specific to E-box sequence in SF-1 promoter region, indicating that POD-1 binds to the SF-1 E-box promoter. Moreover, POD-1 over-expression resulted in a decrease in expression of the SF-1 target gene, StAR (Steroidogenic Acute Regulatory Protein). Lastly, while the induced expression of POD-1 did not affect the cell viability of H295R/POD-1 or ACC-T36/POD-1 cells, the most significantly enriched KEGG pathways for genes negatively correlated to POD-1/TCF21 in 33 human ACCs were those associated with cell cycle genes.

WT1 Maintains Adrenal-Gonadal Primordium Identity and Marks a Population of AGP-like Progenitors within the Adrenal Gland

“…The finding that TCF21 can bind and inhibit the SF1 promoter (Franca et al, 2013; Tamura et al, 2001) provides a molecular explanation for the observed SF1 repression, although we cannot exclude that additional, Tcf21 -independent mechanisms may also contribute to the observed phenotype. Consequently WT1 appears to have a dual function in the development of the adrenal cortex.…”

Fetal adrenal capsular cells serve as progenitor cells for steroidogenic and stromal adrenocortical cell lineages in M. musculus

“…We used Tcf21 +/LacZ knock-in mice to characterize the temporal and spatial activity of the Tcf21 promoter in the mouse adrenal gland (França et al, 2013;Quaggin et al, 1999;Shibata et al, 2003). Although the hormonal profile has not been examined, heterozygous Tcf21 +/LacZ mice are expected to have normal adrenal function as they are viable, fertile and show no symptoms of adrenal hormone deficiencies.…”

“…After separation of the individual adrenal primordia (AP, fetal adrenal gland) and gonadal primordial (GP) from the shared adrenogonadal primordia (AGP), mesenchymal cells migrate and encapsulate the fetal adrenal gland between E11.5 and E12.5 in mice (Else and Hammer, 2005;Keegan and Hammer, 2002) or the 8th to 9th week of gestation in humans (França et al, 2013). The molecular mechanisms involved in this process are not well understood but the capsule has long been characterized as a simple structure that surrounds the gland.…”

Szlaki molekularne w raku kory nadnercza — od wiedzy o sygnalizacji komórkowej do metod diagnostyki i leczenia

“…Multiple copies of SF-1 (NR5A1) gene stimulate tumour development [63]. A study focusing on the SF-1 inhibitor, Pod-1 (capsulin, epicardin, Tcf21), established that the TCF21 gene is down-regulated in ACCs, compared with ACAs and normal tissue [64]. SF-1 over-expression is much more significant in childhood than in adult ACTs.…”

“…Zwielokrotnienie liczby kopii genu SF-1 (NR5A1) stymuluje nowotworzenie [63]. Badania inhibitora SF-1, Pod-1 (capsulin, epicardin, Tcf21), wykazały, że gen TCF21 jest zahamowany w ACC, ale nie w ACA i normalnej tkance [64]. Nadekspresja SF-1 jest o wiele bardziej znacząca w nowotworach u dzieci niż u dorosłych.…”