RESUMO
INTRODUCTION: AMPK (AMP-activated protein kinase) is an enzyme that acts as a metabolic sensor and regulates multiple pathways via phosphorylating proteins in metabolic and proliferative pathways. The aim of this work was to study the activated cellular AMPK (phosphorylated-AMPK at Thr172, pAMPK) levels in pituitary tumor samples from patients with sporadic and familial acromegaly, as well as in samples from normal human pituitary gland. METHODS: We studied pituitary adenoma tissue from patients with sporadic somatotroph adenomas, familial acromegaly with heterozygote germline variants in the aryl hydrocarbon receptor interacting protein (AIP) gene (p.Q164*, p.R304* and p.F269_H275dup) and autopsy from normal pituitary glands without structural alterations. RESULTS: Cellular levels of pAMPK were significantly higher in patients with sporadic acromegaly compared to normal pituitary glands (p < 0.0001). Tissues samples from patients with germline AIP mutations also showed higher cellular levels of pAMPK compared to normal pituitary glands. We did not observe a significant difference in cellular levels of pAMPK according to the cytokeratin (CAM5.2) pattern (sparsely or densely granulated) for tumor samples of sporadic acromegaly. CONCLUSION: Our data show, for the first time in human cells, an increase of cellular levels of pAMPK in sporadic somatotropinomas, regardless of cytokeratin pattern, as well as in GH-secreting adenomas from patients with germline AIP mutations.
Assuntos
Proteínas Quinases Ativadas por AMP , Adenoma , Adenoma Hipofisário Secretor de Hormônio do Crescimento , Humanos , Proteínas Quinases Ativadas por AMP/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Masculino , Adenoma Hipofisário Secretor de Hormônio do Crescimento/genética , Adenoma Hipofisário Secretor de Hormônio do Crescimento/metabolismo , Adenoma Hipofisário Secretor de Hormônio do Crescimento/patologia , Feminino , Pessoa de Meia-Idade , Adulto , Adenoma/genética , Adenoma/patologia , Adenoma/metabolismo , Adenoma/enzimologia , Acromegalia/genética , Acromegalia/patologia , Acromegalia/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Idoso , Neoplasias Hipofisárias/genética , Neoplasias Hipofisárias/patologia , Neoplasias Hipofisárias/metabolismo , Neoplasias Hipofisárias/enzimologia , Fosforilação , Hipófise/metabolismo , Hipófise/patologia , Regulação Neoplásica da Expressão GênicaRESUMO
GH-secreting tumors represent 15 % to 20 % of all pituitary neuroendocrine tumors (pitNETs), of which 95 % occur in a sporadic context, without an identifiable inherited cause. Recent multi-omic approaches have characterized the epigenomic, genomic, transcriptomic, proteomic and kynomic landscape of pituitary tumors. Transcriptomic analysis has allowed us to discover specific transcription factors driving the differentiation of pituitary tumors and gene expression patterns. GH-secreting, along with PRL- and TSH-secreting pitNETs are driven by POU1F1; ACTH-secreting tumors are determined by TBX19; and non-functioning tumors, which are predominantly of gonadotrope differentiation are conditioned by NR5A1. Upregulation of certain miRNAs, such as miR-107, is associated with tumor progression, while downregulation of others, like miR-15a and miR-16-1, correlates with tumor size reduction. Additionally, miRNA expression profiles are linked to treatment resistance and clinical outcomes, providing insights into potential therapeutic targets. Specific somatic mutations in GNAS, PTTG1, GIPR, HGMA2, MAST and somatic variants associated with cAMP, calcium signaling, and ATP pathways have also been associated with the development of acromegaly. This review focuses on the oncogenic mechanisms by which sporadic acromegaly can develop, covering a complex series of molecular alterations that ultimately alter the balance between proliferation and apoptosis, and dysregulated hormonal secretion.
Assuntos
Acromegalia , Neoplasias Hipofisárias , Humanos , Acromegalia/genética , Neoplasias Hipofisárias/genética , Neoplasias Hipofisárias/metabolismo , Neoplasias Hipofisárias/patologia , Tumores Neuroendócrinos/genética , Tumores Neuroendócrinos/patologia , MicroRNAs/genéticaRESUMO
It is usually considered that only 5% of all pituitary neuroendocrine tumours are due to inheritable causes. Since this estimate was reported, however, multiple genetic defects driving syndromic and nonsyndromic somatotrophinomas have been unveiled. This heterogeneous genetic background results in overlapping phenotypes of GH excess. Genetic tests should be part of the approach to patients with acromegaly and gigantism because they can refine the clinical diagnoses, opening the possibility to tailor the clinical conduct to each patient. Even more, genetic testing and clinical screening of at-risk individuals have a positive impact on disease outcomes, by allowing for the timely detection and treatment of somatotrophinomas at early stages. Future research should focus on determining the actual frequency of novel genetic drivers of somatotrophinomas in the general population, developing up-to-date disease-specific multi-gene panels for clinical use, and finding strategies to improve access to modern genetic testing worldwide.
Assuntos
Acromegalia , Testes Genéticos , Gigantismo , Humanos , Acromegalia/genética , Acromegalia/diagnóstico , Acromegalia/terapia , Gigantismo/genética , Gigantismo/diagnóstico , Neoplasias Hipofisárias/genética , Neoplasias Hipofisárias/diagnóstico , Adenoma Hipofisário Secretor de Hormônio do Crescimento/genética , Adenoma Hipofisário Secretor de Hormônio do Crescimento/diagnóstico , Adenoma Hipofisário Secretor de Hormônio do Crescimento/terapiaRESUMO
Acromegaly is a chronic systemic disease caused in the vast majority of cases by growth hormone (GH)-secreting adenoma, with surgery being the first-line treatment. When a cure is not attained with surgery, first-generation somatostatin receptor ligands (fg-SRLs) are the most common medication prescribed. Predictors of response to fg-SRLs have been studied; however, they cannot fully predict the response to fg-SRL. MicroRNAs are small RNAs, the main role of which is messenger RNA (mRNA) post-transcriptional regulation. This study aimed to identify the microRNAs involved in resistance to treatment with fg-SRLs in acromegaly. Ten patients with acromegaly undergoing treatment with fg-SRLs were selected to undergo miRNA sequencing: five controlled and five uncontrolled with treatment. Bioinformatic analysis was performed to detect differentially expressed miRNAs. Then, the same 10 samples were used for validation by qPCR and an additional 22 samples were analyzed, totaling 32 samples. e We found 59 differentially expressed miRNAs in the first analysis. miR-181a-5p and miR-181b-5p were downregulated, and miR-383-5p was upregulated in the uncontrolled group. Receiver operating characteristic (ROC) curve analysis of miR-383-5p showed an NPV of 84.3% and a PPV of 84.5%. In summary, miR-181a-5p, miR-181b-5p, and miR-383-5p are biomarkers of response to fg-SRLs, and they can be used individually or included in prediction models as tools to guide clinical decisions.
Assuntos
Acromegalia , MicroRNAs , Humanos , Acromegalia/genética , Receptores de Somatostatina/genética , MicroRNAs/genética , MicroRNAs/uso terapêuticoRESUMO
Acromegaly is a chronic and systemic disease due to excessive growth hormone and insulin-like growth factor type I caused, in the vast majority of cases, by a GH-secreting pituitary adenoma. About 40% of these tumors have somatic mutations in the stimulatory G protein alpha-subunit 1 gene. The pathogenesis of the remaining tumors, however, is still not fully comprehended. Surgery is the first-line therapy for these tumors, and first-generation somatostatin receptor ligands (fg-SRL) are the most prescribed medications in patients who are not cured by surgery. MicroRNAs are small, non-coding RNAs that control the translation of many mRNAs, and are involved in the post-transcriptional regulation of gene expression. Differentially expressed miRNAs can explain differences in the pathogenesis of acromegaly and tumor resistance. In this review, we focus on the most validated miRNAs, which are mainly involved in acromegaly's tumorigenesis and fg-SRL resistance, as well as in circulating miRNAs in acromegaly.
Assuntos
Acromegalia , Adenoma , Hormônio do Crescimento Humano , MicroRNAs , Acromegalia/genética , Adenoma/metabolismo , Hormônio do Crescimento Humano/uso terapêutico , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , MicroRNAs/genética , MicroRNAs/uso terapêutico , Receptores de Somatostatina/genética , Receptores de Somatostatina/metabolismo , Somatostatina/genética , Somatostatina/uso terapêuticoRESUMO
SUMMARY Carney complex (CNC) is a rare syndrome of multiple endocrine and non-endocrine tumors. In this paper we present a 23-year-old Iranian woman with CNC who harbored a novel mutation (c.642dupT) in PRKAR1A gene. This patient presented with pituitary macroadenoma, acromegaly, recurrent atrial myxoma, Cushing's syndrome secondary to primary pigmented nodular adrenocortical disease and pigmented schwanoma of the skin. PRKAR1A gene was PCR amplified using genomic DNA and analyzed for sequence variants which revealed the novel mutation resulting in substitution of amino acid cysteine instead of the naturally occurring valine in the peptide chain and a premature stop codon at position 18 (V215CfsX18). This change leads to development of tumors in different organs due to lack of tumor suppressive activity secondary to failure of synthesis of the related protein.
Assuntos
Humanos , Feminino , Adulto , Adulto Jovem , Acromegalia/genética , Síndrome de Cushing/genética , Complexo de Carney/genética , Mixoma/cirurgia , Mixoma/genética , Subunidade RIalfa da Proteína Quinase Dependente de AMP Cíclico/genética , Irã (Geográfico) , MutaçãoRESUMO
Carney complex (CNC) is a rare syndrome of multiple endocrine and non-endocrine tumors. In this paper we present a 23-year-old Iranian woman with CNC who harbored a novel mutation (c.642dupT) in PRKAR1A gene. This patient presented with pituitary macroadenoma, acromegaly, recurrent atrial myxoma, Cushing's syndrome secondary to primary pigmented nodular adrenocortical disease and pigmented schwanoma of the skin. PRKAR1A gene was PCR amplified using genomic DNA and analyzed for sequence variants which revealed the novel mutation resulting in substitution of amino acid cysteine instead of the naturally occurring valine in the peptide chain and a premature stop codon at position 18 (V215CfsX18). This change leads to development of tumors in different organs due to lack of tumor suppressive activity secondary to failure of synthesis of the related protein.
Assuntos
Acromegalia , Complexo de Carney , Síndrome de Cushing , Mixoma , Acromegalia/genética , Adulto , Complexo de Carney/genética , Síndrome de Cushing/genética , Subunidade RIalfa da Proteína Quinase Dependente de AMP Cíclico/genética , Feminino , Humanos , Irã (Geográfico) , Mutação , Mixoma/genética , Mixoma/cirurgia , Adulto JovemRESUMO
PURPOSE: Acromegaly is a cause of secondary osteoporosis and is associated with increased risk of vertebral fractures (VFs). The influence of exon 3-deleted isoform of growth hormone receptor (d3-GHR) on bone microarchitecture has not been studied in acromegaly. AIM: The aim of this study was to analyze the associations between d3-GHR isoform and bone mineral density (BMD), bone microarchitecture, and VFs in acromegaly patients. METHODS: Consecutive acromegaly patients treated at a single reference center were included. BMD was analyzed using dual-energy X-ray absorptiometry (DXA) and bone microarchitecture was analyzed by high-resolution peripheral quantitative computed tomography (HR-pQCT). The presence of moderate to severe VFs was assessed by thoracic and lumbar X-ray. GHR genotyping was analyzed by PCR, and full-length isoform of GHR (fl-GHR) was represented by a 935-bp fragment and d3-GHR by a 532-bp fragment. RESULTS: Eighty-nine patients were included [56 females; median age at diagnosis: 43 years (17-78)]. Disease was uncontrolled in 63% of patients. At least one d3-GHR allele was present in 60% of patients. Frequency of active disease (p = 0.276) and hypogonadism (p = 1.000) was not different between patients with fl-GHR and those with at least one d3-GHR. There was no difference in any DXA or HR-pQCT parameters between patients with fl-GHR and those with d3-GHR. Significant VFs were observed in 14% of patients, but there was no difference in frequency between patients with fl-GHR and those with at least one d3-GHR allele (p = 0.578). CONCLUSIONS: Presence of d3-GHR was not associated with worse BMD or bone microarchitecture or with higher frequency of significant VFs.
Assuntos
Acromegalia/diagnóstico por imagem , Acromegalia/genética , Densidade Óssea/genética , Éxons/genética , Fraturas Ósseas/diagnóstico por imagem , Fraturas Ósseas/genética , Receptores da Somatotropina/genética , Absorciometria de Fóton/métodos , Acromegalia/sangue , Adolescente , Adulto , Idoso , Feminino , Fraturas Ósseas/sangue , Hormônio do Crescimento Humano/sangue , Hormônio do Crescimento Humano/genética , Humanos , Masculino , Pessoa de Meia-Idade , Isoformas de Proteínas/sangue , Receptores da Somatotropina/sangue , Estudos Retrospectivos , Fatores de Risco , Adulto JovemRESUMO
Filamin-A (FLNA) plays a crucial role in somatostatin receptor (sst) subtype-2 signaling in somatotropinomas. Our objective was to investigate the in vivo association between FLNA and sst2 expression, sst5 expression, dopamine receptor subtype-2 (D2) expression, somatostatin receptor ligand (SRL) responsiveness and tumor invasiveness in somatotropinomas. Quantitative real-time PCR was used to evaluate the absolute mRNA copy numbers of FLNA/sst2/sst5/D2 in 96 somatotropinomas. FLNA, sst2 and sst5 protein expression levels were also evaluated using immunohistochemistry. The Knosp-Steiner criteria were used to evaluate tumor invasiveness. Median FLNA, sst2, sst5 and D2 copy numbers were 4,244, 731, 156 and 3,989, respectively. Thirty-one of the 35 available tumors (89%) were immune positive for FLNA in the cytoplasm and membrane but not in the nucleus. FLNA and sst5 expression were positively correlated at the mRNA and protein levels (p < 0.001 and p = 0.033, respectively). FLNA was positively correlated with sst2 mRNA in patients who were responsive to SRL (p = 0.014, R = 0.659). No association was found between FLNA and tumor invasiveness. Our findings show that in somatotropinomas FLNA expression positively correlated with in vivo sst5 and D2 expression. Notably, FLNA was only correlated with sst2 in patients who were controlled with SRL. FLNA was not associated with tumor invasiveness.
Assuntos
Acromegalia/genética , Adenoma/tratamento farmacológico , Antineoplásicos/administração & dosagem , Filaminas/genética , Adenoma Hipofisário Secretor de Hormônio do Crescimento/tratamento farmacológico , Receptores de Dopamina D2/genética , Receptores de Somatostatina/genética , Acromegalia/etiologia , Acromegalia/metabolismo , Adenoma/complicações , Adenoma/genética , Adenoma/metabolismo , Adolescente , Adulto , Idoso , Antineoplásicos/uso terapêutico , Membrana Celular/genética , Membrana Celular/metabolismo , Núcleo Celular/genética , Núcleo Celular/metabolismo , Citoplasma/genética , Citoplasma/metabolismo , Feminino , Filaminas/metabolismo , Adenoma Hipofisário Secretor de Hormônio do Crescimento/complicações , Adenoma Hipofisário Secretor de Hormônio do Crescimento/genética , Adenoma Hipofisário Secretor de Hormônio do Crescimento/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Octreotida/administração & dosagem , Octreotida/uso terapêutico , Peptídeos Cíclicos/administração & dosagem , Peptídeos Cíclicos/uso terapêutico , Receptores de Dopamina D2/metabolismo , Receptores de Somatostatina/metabolismo , Somatostatina/administração & dosagem , Somatostatina/análogos & derivados , Somatostatina/uso terapêutico , Carga Tumoral , Adulto JovemRESUMO
ß-arrestins seem to have a role in endocytosis and desensitization of somatostatin receptor subtype 2 (sst2) and could be associated with the responsiveness to somatostatin receptor ligands (SRL) in patients with acromegaly. To investigate the in vivo correlation between ß-arrestins 1 and 2 with sst2, sst5 and dopamine receptor subtype 2 (D2) expressions, and the association of ß-arrestins with response to first-generation SRL and invasiveness in somatotropinomas. ß-arrestins 1 and 2, sst2, sst5 and D2 mRNA expressions were evaluated by quantitative real-time RT-PCR on tumoral tissue of 96 patients. Moreover, sst2 and sst5 protein expressions were also evaluated in 40 somatotropinomas by immunohistochemistry. Response to SRL, defined as GH <1 µg/l and normal IGF-I levels, was assessed in 40 patients. The Knosp-Steiner criteria were used to define invasiveness. Median ß-arrestin 1, ß-arrestin 2, sst2, sst5 and D2 mRNA copy numbers were 478; 9375; 731; 156; and 3989, respectively. There was a positive correlation between ß-arrestins 1 and 2 (R = 0.444, P < 0.001). However, no correlation between ß-arrestins and sst2, sst5 (mRNA and protein levels) or D2 was found. No association was found between ß-arrestins expression and SRL responsiveness or tumour invasiveness. Although previous data suggest a putative correlation between ß-arrestins and sst2, our data clearly indicated that no association existed between ß-arrestins and sst2, sst5 or D2 expression, nor with response to SRL or tumour invasiveness. Therefore, further studies are required to clarify whether ß-arrestins have a role in the response to treatment with SRL in acromegaly.