Insulin-like growth factor--phosphatidylinositol 3 kinase signaling in canine cortisol-secreting adrenocortical tumors

Single-nucleus and spatial transcriptome reveal adrenal homeostasis in normal and tumoural adrenal glands

The human adrenal gland is a complex endocrine tissue. Studies on adrenal renewal have been limited to animal models or human foetuses. Enhancing our understanding of adult human adrenal homeostasis is crucial for gaining insights into the pathogenesis of adrenal diseases, such as adrenocortical tumours. Here, we present a comprehensive cellular genomics analysis of the adult human normal adrenal gland, combining single-nuclei RNA sequencing and spatial transcriptome data to reconstruct adrenal gland homeostasis. As expected, we identified primary cells of the various zones of the adrenal cortex and medulla, but we also uncovered additional cell types. They constitute the adrenal microenvironment, including immune cells, mostly composed of a large population of M2 macrophages, and new cell populations, including different subpopulations of vascular-endothelial cells and cortical-neuroendocrine cells. Utilizing spatial transcriptome and pseudotime trajectory analysis, we support evidence of the centripetal dynamics of adrenocortical cell maintenance and the essential role played by Wnt/β-catenin, sonic hedgehog, and fibroblast growth factor pathways in the adult adrenocortical homeostasis. Furthermore, we compared single-nuclei transcriptional profiles obtained from six healthy adrenal glands and twelve adrenocortical adenomas. This analysis unveiled a notable heterogeneity in cell populations within the adenoma samples. In addition, we identified six distinct adenoma-specific clusters, each with varying distributions based on steroid profiles and tumour mutational status. Overall, our results provide novel insights into adrenal homeostasis and molecular mechanisms potentially underlying early adrenocortical tumorigenesis and/or autonomous steroid secretion. Our cell atlas represents a powerful resource to investigate other adrenal-related pathologies.

Objective assessment of adrenocortical carcinoma driver genes and their correlation with tumor pyruvate kinase M2

Glandular cancers have a significant share of the total cancer patients all over the world. In the case of adrenocortical carcinomas (ACCs), although the benign form is more frequent and common, the malignant form provides a very less percentage of patients with five or more than five years of survival rate. There are gene alterations that are involved as a crucial factor behind the occurrence of ACCs. Out of these, the most prominent genetic alterations (PRKAR-1A, CTNNB1, ZNRF3, TP53, CCNE1 and TERF2 genes) are linked with a glycolytic enzyme pyruvate kinase M2 (PKM2), which converts phosphoenolpyruvate (PEP) to pyruvate in the glycolytic pathway. The involvementof PKM2 renders a cumulative effect through different pathways that may result in the onset of ACCs. Thus, this review aims to establish a link between ACCs, alterations of specific genes and PKM2.

Alterations of DNA methylation were associated with the rapid growth of cortisol-producing adrenocortical adenoma during pregnancy

Background

Cortisol-producing adrenocortical adenoma (CPA) during pregnancy rarely occurs in clinic. Growing evidence suggests that DNA methylation plays a key role in adrenocortical adenomas. The present study aims to examine the genome-wide DNA methylation profiles and identify the differences in DNA methylation signatures of non-pregnant and pregnant patients with CPA.

Results

Four pregnant and twelve non-pregnant patients with CPA were enrolled. The pregnant patients with CPA had higher serum cortisol, Estradiol, Progesterone, and human chorionic gonadotropin concentration, while having lower serum FSH (follicle-stimulating hormone) and luteinizing hormone concentrations (P < 0.01). Compared with the non-pregnant patients, the duration is shorter, and the growth rate of the tumor is faster in pregnant patients with CPA (P < 0.05). Morphology and cell proliferation assay showed that the percentage of Ki-67 positive cells in CPA were higher in pregnant group than non-pregnant group (8.0% vs 5.5%, P < 0.05). The DNA methylation analysis showed that Genome-wide DNA methylation signature difference between pregnant and non-pregnant with CPA, that the pregnant group had more hypermethylated DMPs (67.94% vs 22.16%) and less hypomethylated DMPs (32.93% vs 77.84%). The proportion of hypermethylated DMPs was relatively high on chromosomes 1 (9.68% vs 8.67%) and X (4.99% vs 3.35%) but lower on chromosome 2(7.98% vs 12.92%). In pregnant patients with CPA, 576 hypomethylated DMPs and 1109 hypermethylated DMPs were identified in the DNA promoter region. Bioinformatics analysis indicated that the Wnt/β-Catenin pathway, Ras/MAPK Pathway and PI3K-AKT Pathway were associated with the development of CPA during pregnancy.

Conclusions

Genome-wide DNA methylation profiling of CPA in non-pregnant and pregnant patients was identified in the present study. Alterations of DNA methylation were associated with the pathogenesis and exacerbation of CPA during pregnancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01205-3.

Is there a role for the IGF system and epidermal growth factor (EGF) in the pathogenesis of adrenocortical adenomas? A preliminary case-control study

Adrenal incidentalomas (AI) are very common and mostly they are non-functioning adenomas (NFA). NFAs are often associated with insulin resistance and metabolic syndrome. Several biomarkers, including certain growth factors, may participatein the pathogenesis ofmetabolic changes in patients with adrenal adenomas.Patients with NFA and age-matched control subjects were enrolled in the study. Data on age, gender, presence of metabolic syndrome or its components were obtained for each subject. Blood samples were obtained and glycemia, insulinemia, lipid profile, and selected growth factor levels were measured. Forty-three patients with NFA and 40 controls were included in the study. Differences were not found in the metabolic syndrome and its components prevalence or in the biochemical profile between patients and the control group. Significant differences were noticed in the levels of IGF1, IGF2, and IGFBP3 (p=0.016, p=0.005, p=0.004, respectively), but there were no differences in VEGF or EGF concentrations. In NFA patients, an association between glycemia and EGF levels was present (p=0.026). No significant correlations between tumor size and insulin or growth factor concentrations were present in AI patients. Significantly higher serum IGF1, IGF2, and IGFBP3 concentrations in NFA patients may support the role of the IGF axis in the pathogenesis of adrenocortical lesions.No correlation between IGFs or IGFBP3 and parameters of glucose or lipid metabolism was found. Present results may support the role of the growth hormone axis rather than hyperinsulinemia and insulin resistance in the pathogenesis of adrenocortical adenomas.

Cortisol-secreting adrenocortical tumours in dogs and their relevance for human medicine

Spontaneous cortisol-secreting adrenocortical tumours in pet dogs are an attractive animal model for their human counterparts. Adrenal morphology and function are similar in dogs and humans, and adrenocortical tumours have comparable clinical and pathological characteristics. Their relatively high incidence in pet dogs represents a potential source of adrenocortical tumour tissue to facilitate research. The molecular characteristics of canine cortisol-secreting adrenocortical tumours suggest that they will be useful for the study of angiogenesis, the cAMP/protein kinase A pathway, and the role of Steroidogenic Factor-1 in adrenal tumourigenesis. Pet dogs with spontaneous cortisol-secreting adrenocortical tumours may also be useful in clinical testing of new drugs and in investigating the molecular background of adrenocortical tumours.