Endocrine Abstracts

Introduction: Adrenocortical carcinoma (ACC) is one of the most aggressive endocrine malignancies and confers a poor prognosis in advanced stages. Effective treatments are lacking. The results of immune checkpoint inhibition were disappointing with few responders only deriving clinical benefit. For the development of novel immunotherapies such as tumor vaccines and T cell-based treatments, target identification is essential. Tumor-specific mutant neoantigens that may be recogn...

Context: Adrenocortical carcinoma (ACC) are endocrine malignant neoplasms associated with severe aggressiveness. Tumour-related glucocorticoid excess occurs in 60% of patients and is associated with poor prognosis. First clinical trials using immune checkpoint inhibitors are quite unsatisfactory and treatment advancements are urgently needed.Recently, we characterized tumour-infiltrating lymphocytes (TILs) in ACC and identified the detrimental dependency...

Adrenocortical carcinoma (ACC) is a rare malignancy with heterogeneous but dismal prognosis and despite numerous efforts to improve patient care, effective treatment options are still lacking. ACC in vitro research faces for decades one major obstacle - the unavailability of different ACC cell line models. Here, we present a newly established human ACC cell line that was directly transferred to and now proliferates in cell culture. JIL-O cell line was derived from a p...

Background: Ferroptosis is an emerging form of regulated necrotic cell death characterized by excessive lipid peroxidation. Adrenocortical carcinoma (ACC) cells have been shown to be highly susceptible to ferroptosis caused by active steroid hormone synthesis. While therapeutic activation of ferroptosis has been proposed as a novel treatment strategy, its impact on the tumor immune microenvironment (TIME) remains elusive. Macrophages are an important TIME component and modulat...

Background: Mitotane is the only drug approved for treatment of adrenocortical carcinoma (ACC). We have found that mitotane leads to endoplasmic reticulum stress and decreased viability in ACC cells. It is not known by which downstream mechanisms cell death is induced by mitotane.Aim: To characterize the mechanisms underlying cell death resulting from mitotane treatment in ACC cells.Methods: Lipid peroxidation in the ACC cell line ...

In a previous study we found mutations in the main catalytic subunit of protein kinase A (PKA Cα) to be responsible for cortisol-secreting adrenocortical adenomas (ACAs). These mutations interfere with the formation of a stable holoenzyme, thus causing constitutive PKA activation. More recently, we identified additional mutations affecting PKA Cα in ACAs associated with overt Cushing syndrome: Ser213Arg_Leu212_Lys214insIle-Ile-Leu-Arg, Cys200_Gly201insVal, Trp197Arg,...

Recently, mutations in the PRKACA (catalytic subunit α of the PKA) gene have been identified as causative in 35% of adrenocortical adenomas (ACA) with overt Cushing’s syndrome (Beuschlein et al. 2014). These mutations lead to constitutive activation of PKA signaling and subsequently to an excessive production of cortisol. Protein kinase A is a heterotetramer consisting of two catalytic and two regulatory subunits with several isoforms (Cα, β, &#947...

Background: Mitotane is the only approved treatment for advanced adrenocortical carcinoma and was shown to inhibit Sterol-O-Acyl transferase 1 (SOAT1) which leads to the depletion of cholesterol esters and increase of free cholesterol in the ACC cell line H295R. Downstream activation of the endoplasmic reticulum stress (ER-stress) pathway results in decreased adrenocortical cell viability.Aim: To better characterize the effects of SOAT1 inhibition in ACC...

Protein Kinase A (PKA) consists of two catalytic and two regulatory subunits with several isoforms (Cα, β, γ and RIα, IIα, Iβ, IIβ, respectively). Type II regulatory subunits are phosphorylated by PKA in their inhibitory sites, while type I are not. Somatic activating mutations in the gene encoding the catalytic subunit α (Cα) of PKA (PRKACA) have been found in 30–40% of cortisol-producing adrenocortical adenomas (CPA). We rece...

We previously identified mutations in PRKACA, coding for the catalytic a (Ca) subunit of protein kinase A (PKA), as the main genetic alteration in cortisol-producing adrenal adenomas (CPAs) responsible for Cushing’s syndrome. Here, we further investigated the mechanism of action of all PRKACA mutations identified so far by our team (L206R, L199_C200_insW, S213R_L212_K214insIILR, C200_GlyinsV, W197R, del244-248+E249Q and E32V). Five out of seven mutants s...