ABSTRACT: Despite the intensive search for an effective drug to ameliorate excess steroid production, there are few pharmacological options, especially for diseases as steroid-producing adrenocortical cancers. While splice-modifying-compounds have pleiotropic effects including anticancer properties, none have been tested on abnormal steroidogenesis. Using H295R adrenocortical carcinoma cells, CX-4945 induced multiple exon skipping of the NR5A1 gene, the master regulator of steroidogenesis. The resulting exon-skipped NR5A1 proteins were non-functional when added-back to NR5A1 knocked down H295R cells. This eventually suppressed steroidogenesis and induced dysfunctional autophagy with progression to ER-stress-related apoptosis. Intriguingly, a circular RNA of NR5A1 exons (circNR5A1 ex2-4 RNA) not originating from the skipped exons, was induced. Transient expression of this circNR5A1 ex2-4 RNA induced the same multiple exon-skipped isoforms of the NR5A1 gene. This potential pharmacological control of NR5A1 aberrant multiple exon-skipping and interplay with its circNR5A1 RNA gives us a novel target for treating abnormal steroidogenesis in adrenocortical carcinomas.
Project description:Despite the intensive search for an effective drug to treat steroid-producing adrenocortical carcinomas, there are few therapeutic options. We sought whether splicing modifying compounds are effective on this devastating disease. Here, we show that a chemical compound in clinical trial, CX-4945, suppressed the expression of NR5A1 through aberrant multiple exon skipping leading to suppressed steroidogenesis and induced dysfunctional autophagy and progression to ER-stress-related apoptosis. A circular RNA of NR5A1 exons with an IRE1α-cleavage site on the ligated ends (circAd4BP HAC1-type ex1-6 RNA) is expressed in normal adrenal cortex but not in H295R adrenocortical cancer cells, and CX-4945 induced a different circular RNA of NR5A1 exons (circAd4BP ex2-4 RNA). This potential pharmacological control of abnormal steroidogenesis through NR5A1 aberrant splicing and interplay with its circAd4BP makes CX-4945 a strong candidate novel drug for the treatment of adrenocortical carcinomas.
Project description:Transcription factor 21 (TCF21) directly binds and regulates SF1 in tumor and normal adrenocortical cells, and both are involved in the development and steroidogenesis of the adrenal cortex. TCF21 is a tumor suppressor gene and its expression is reduced in malignant tumors. In adrenocortical tumors, it is less expressed in adrenocortical carcinomas (ACC) than in adrenocortical adenomas (ACA) and normal tissue. However, a comprehensive analysis to identify TCF21 targets have not yet been conducted in any type of cancer. In this study, we performed Chromatin Immunoprecipitation and Sequencing (ChIP-Seq) in adrenocortical carcinoma cell line (NCI-H295R) overexpressing TCF21, with the aim of identifying TCF21 new targets. The five most frequently identified sequences corresponded to the PRDM7, CNTNAP2, CACNA1B, PTPRN2 and KCNE1B genes. Validation experiments showed that, in NCI-H295R cells, TCF21 regulates gene expression positively in PRDM7 and negatively in CACNA1B. Recently, it was observed that the N-type calcium channel v2.2 (Cav2.2) encoded by CACNA1B gene is important in Angiotensin II signal transduction for corticosteroid biosynthesis in NCI-H295R adrenocortical carcinoma cells. Indeed, TCF21 inhibits CACNA1B and Cav2.2 expression in NCI-H295R. In addition, in a cohort of 55 adult patients with adrenocortical tumor, CACNA1B expression was higher in ACC than ACA, and was related to poor disease-free survival in ACC patients. These results suggest a mechanism of steroidogenesis control by TCF21 in adrenocortical tumor cells, in addition to the control observed through SF1 inhibition. Importantly, steroid production could impair tumor immunogenicity, contributing to the immune resistance described in adrenal cancer.
Project description:we induce exon skipping and generate a gain-of-function of an oncogene, β-catenin, using CRISPR/Cas9 in mouse liver cells. Specifically, a single guide RNA (sgRNA) targeting exon 3 of β-catenin induces exon skipping and gain-of-function of β-catenin in mouse hepatocytes. In synergy with YAPS127A, exon skipped hepatocytes gain tumorigenic ability and are thus enriched via tumor formation. Surprisingly, characterization of the exon-skipped tumors reveals two distinct subtypes with different histological features. Remarkably, ectopic expression of two representative exon-skipped β-catenin transcripts together with YAPS127A phenocopies the two histologically distinct subtypes of liver cancer. Finally, the transcriptome sequencing analysis reveal two subtypes of liver cancer and most importantly, one subtype of the exon-skipped tumor shows features of hepatoblastoma, while the other does not. This exon skipping model reveals CRISPR/Cas9 can lead to exon-skipped transcripts with in frame coding and gain-of-functions.
Project description:RNA sequencing provides a transcriptome-wide view of what processes are activated and repressed during steroidogenesis. Here we performed an RNA-seq time series on primary human adrenocortical cells and H295R cells stimulated with ACTH or AngII (forskolin for H295R). We found that the ligand-induced changes in gene expression largely involved the same genes and similar timing. While stimulus-induced expression changes in H295R cells are recapitulated by primary cells, there are also expression changes unique to primary cells.
Project description:The adrenal cortex produces vital steroid hormones that maintain homeostasis. While steroid hormones produced from the fetal zone adrenal cortex are essential for both fetal development and maintenance of pregnancy, the molecular mechanisms leading to human adrenal cortex development and steroid synthesis remain poorly understood due to the paucity of model systems. Through progressive generation of fetal zone adrenal cortex-like cells (FZLCs) from human induced pluripotent stem cells through posterior intermediate mesoderm-like, adrenogenic coelomic epithelium and adrenal primordium-like states, we provide the first in vitro reconstitution of human adrenocortical fetal specification. Generation of FZLCs faithfully recapitulates human embryonic adrenal cortex specification as evidenced by histomorphological and ultrastructural analysis, transcriptional profiles and delta-5 steroid biosynthesis and occurs in an adrenocorticotropic hormone (ACTH)-independent manner, consistent with clinical observations. Furthermore, we demonstrate that FZLC generation is promoted by SHH and inhibited by NOTCH, ACTIVIN and WNT signaling and that steroid synthesis is amplified by ACTH/PKA signaling and blocked by pharmacologic inhibitors of delta 5 steroid synthesis enzymes. Finally, NR5A1 appear to self-stabilize its promoter activity and promote FZLC survival and steroidogenesis. Together, these findings provide a framework for understanding and reconstituting human adrenocortical development in vitro and pave the way for future cell-based therapies of adrenal insufficiency.
Project description:The adrenal cortex produces vital steroid hormones that maintain homeostasis. While steroid hormones produced from the fetal zone adrenal cortex are essential for both fetal development and maintenance of pregnancy, the molecular mechanisms leading to human adrenal cortex development and steroid synthesis remain poorly understood due to the paucity of model systems. Through progressive generation of fetal zone adrenal cortex-like cells (FZLCs) from human induced pluripotent stem cells through posterior intermediate mesoderm-like, adrenogenic coelomic epithelium and adrenal primordium-like states, we provide the first in vitro reconstitution of human adrenocortical fetal specification. Generation of FZLCs faithfully recapitulates human embryonic adrenal cortex specification as evidenced by histomorphological and ultrastructural analysis, transcriptional profiles and delta-5 steroid biosynthesis and occurs in an adrenocorticotropic hormone (ACTH)-independent manner, consistent with clinical observations. Furthermore, we demonstrate that FZLC generation is promoted by SHH and inhibited by NOTCH, ACTIVIN and WNT signaling and that steroid synthesis is amplified by ACTH/PKA signaling and blocked by pharmacologic inhibitors of delta 5 steroid synthesis enzymes. Finally, NR5A1 appear to self-stabilize its promoter activity and promote FZLC survival and steroidogenesis. Together, these findings provide a framework for understanding and reconstituting human adrenocortical development in vitro and pave the way for future cell-based therapies of adrenal insufficiency.
Project description:The adrenal cortex produces vital steroid hormones that maintain homeostasis. While steroid hormones produced from the fetal zone adrenal cortex are essential for both fetal development and maintenance of pregnancy, the molecular mechanisms leading to human adrenal cortex development and steroid synthesis remain poorly understood due to the paucity of model systems. Through progressive generation of fetal zone adrenal cortex-like cells (FZLCs) from human induced pluripotent stem cells through posterior intermediate mesoderm-like, adrenogenic coelomic epithelium and adrenal primordium-like states, we provide the first in vitro reconstitution of human adrenocortical fetal specification. Generation of FZLCs faithfully recapitulates human embryonic adrenal cortex specification as evidenced by histomorphological and ultrastructural analysis, transcriptional profiles and delta-5 steroid biosynthesis and occurs in an adrenocorticotropic hormone (ACTH)-independent manner, consistent with clinical observations. Furthermore, we demonstrate that FZLC generation is promoted by SHH and inhibited by NOTCH, ACTIVIN and WNT signaling and that steroid synthesis is amplified by ACTH/PKA signaling and blocked by pharmacologic inhibitors of delta 5 steroid synthesis enzymes. Finally, NR5A1 appear to self-stabilize its promoter activity and promote FZLC survival and steroidogenesis. Together, these findings provide a framework for understanding and reconstituting human adrenocortical development in vitro and pave the way for future cell-based therapies of adrenal insufficiency.
Project description:Androgens are essential for sexual development and reproduction. However, androgen regulation in health and disease is poorly understood. Previously, we showed that human adrenocortical H295R cells grown under starvation conditions acquire a hyperandrogenic steroid profile with changes in steroid metabolizing enzymes HSD3B2 and CYP17A1 essential for androgen production. Furthermore, we have shown that metformin inhibits androgen production of steroidogenic H295R cells and inhibits complex I activity of the respriatory chain. Therefore, to search for underlying mechanisms regulting androgen production and to understand the basic biology of androgens, we have characterized the gene expression profile of H295R cells grown under normal growth conditions, serum starvation (hyperandrogenic) growth conditions as well as after metformin treatment (hypoandrogenic). In this dataset, we first characterized the gene expression profile of H295R cells cultured under nromal growth vs serum-starved (hypernadrogenic) growth conditions. Expression profiling of starved H295R cells revealed alterations in genes involved in steroid and energy metabolism and signal transduction. We discovered two new gene networks around RARB and ANGPTL1, and show how they regulate androgen biosynthesis (Udhane SS et al.,2015). In a second part, we compared the gene expression profile of H295R cells grown under serum starvation (hyperandrogenic) conditions to metformin treated (hypoandrogenic) cells in search for the underlying androgen regulating network. (Udhane et al., manuscript in preparation).