Genotoxic or Oxidative Stress Induces Cell-Autonomous Steroidogenesis in Human Adrenocortical Tumor H295R Cells

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SUN 203-235-Steroid Hormone Actions, Biosynthesis and Metabolism (posters)
Bench to Bedside
Sunday, April 3, 2016: 1:15 PM-3:15 PM
Exhibit/Poster Hall (BCEC)

Poster Board SUN 204
Mimi Tamamori-Adachi*1, Takao Susa1, Hiroko Fujii2, Harumi Hisaki1, Masayoshi Iizuka1 and Tomoki Okazaki1
1Teikyo Univ Schl of Med, Tokyo, Japan, 2Japan Self Defence Forces Ctr Hp, Tokyo, Japan
   Glucocorticoid production is regulated by ACTH via the cyclic adenosine monophosphate (cAMP) /cAMP-dependent protein kinase A (PKA) pathway in the adrenal cortex. In this study, we show that cell-autonomous steroidogenesis is induced by genotoxic and oxidative stress in cultured human adrenocortical carcinoma cells (H295R). Etoposide (EP) and H2O2 were used to induce DNA damage via genotoxic and oxidative stress, respectively. Microarray expression profiling of EP-, or H2O2-treated versus normal cells and quantitative RT-PCR assay revealed that expression of stress associated gene GADD45A in addition to steroidogenesis-related genes including HSD3B1, HSD3B2, CYP11B1, CYP11B2, NR4A1, NR4A2, and MC2R was significantly upregulated. Immunofluorescence showed that GADD45A protein clearly accumulated in nuclei of EP- or H2O2- treated cells. Metabolite assay in the cultured media showed that EP- or H2O2-treated cells were induced to produce and secrete glucocorticoid more robustly than aldosterone, which was a predominant steroid species in a stress-free condition in these cells. Knockdown of GADD45A using siRNA markedly inhibited EP-induced upregulation of those steroidogenesis-related genes expression in quantitative RT-PCR experiments, and glucocorticoid production. However, the inhibitory effect on H2O2-induced steroidogenesis was not significant. A PKA inhibitor H89 did not inhibit EP- or H2O2-induced glucocorticoid production. These results suggest that EP- or H2O2-stimulated steroidogenesis is promoted via an unprecedented pathway(s). Specifically, GADD45A, a stress-associated protein, plays an important role in EP-stimulated genotoxic stress induced steroidogenesis. In summary, there is multiplicity in the adrenal stress system and our study will shed new light on the mechanism of steroidogenesis against various stresses.

Nothing to Disclose: MT, TS, HF, HH, MI, TO

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