Endocrine Abstracts

Neuroendocrine tumors (NETs) are rare neoplasms showing a wide spectrum of clinical behaviors. The therapeutic options available for NET treatment are rarely curative and most are palliative, as NETs frequently show resistance to pharmacological therapy. Cancers develop in complex tissue environments, which they depend upon for sustained growth, invasion and metastasis. A major characteristic of the tumor microenvironment is inflammatory cell infiltration, where tumor-associat...

Metformin (1.1-dimethylbiguanide hydrochloride), a widely used antidiabetic drug, has been reported to display potent anticancer properties in various types of cancers, including neuroendocrine tumors. Recently, a potential synergistic activity between metformin and octreotide (SSA) in Pancreatic Neuroendocrine Tumors (P-NETs) has been proposed. AIP (aryl hydrocarbon receptor-interacting protein) acts as tumor suppressor gene in neuroendocrine tumors at pituitary level and it ...

Somatostatin exerts its inhibitory effects on hormone secretion and cell proliferation via five receptors subtypes (SST1-SST5). After agonist binding, receptor residues mainly located in the carboxyl terminal (CT) and in the third intracellular loop (IC3) are phosphorylated and β-arrestins are recruited to drive SSTRs internalization.Aim of the study is to characterize the intracellular mechanisms responsible for SST2 internalization and identify th...

Neuroendocrine neoplasms (NENs) are rare tumour showing a wide spectrum of clinical behaviours. Therapeutic options available for NET treatment are rarely curative and mostly palliative, as NETs frequently show resistance to pharmacological therapy. Cancers develop in complex tissue environments, which they depend on. Tumour-associated macrophages (TAMs) are a major cellular component of the tumour microenvironment. Two polarized state of macrophages are described in literatur...

cAMP is implicated in the inhibition or stimulation of proliferation depending on cell type. The activation of cAMP–PKA pathway generates proliferative signals in GH-secreting adenomas whereas this effect is not present, or even opposite, in non-functioning pituitary cells (NFPA). Although cAMP effects were initially attributed to PKA activation, recently the discovery of two cAMP-activated guanine nucleotide exchange factors (Epac1,2) was proposed as a novel mechanism fo...

Dopamine agonists (DA) inhibit prolactin (PRL) secretion and expression on the pituitary lactotrophs by binding dopamine D2 receptor. Prolactinomas are the most common secreting pituitary adenomas, and DA are the first choice for their treatment because they reduce PRL levels and tumor size. However, a subset of patients is resistant to DA. The mechanisms involved in DA resistance are not fully understood, although decreased expression of D2 receptor or altered signal transduc...

Background: The fourth type of Multiple Endocrine Neoplasia (MEN) is a rare variant of MEN presenting a MEN1-like phenotype and originating from a germline mutation in CDKN1B. However, due to the small number of cases documented in literature, the peculiar clinical features of MEN4 are still largely unknown, and clear indications about the clinical management of these patients are currently lacking. In order to enlarge our knowledge on MEN4 and to better typify the clinical fe...

Pulmonary neuroendocrine tumors (PNTs) comprise a spectrum of neoplasms, ranging from low grade carcinoids to the highly malignant small cell lung cancers. Several studies identified cytoskeleton protein Filamin A (FLNA) as determinant in cancer progression and metastasis. To date, the role of FLNA in PNTs aggressiveness and progression is still unknown.To address this question, we decided: i) to evaluate FLNA expression in PNTs ranging from typical carc...

Somatostatin receptor type 2 (SST2) is the main pharmacological target of long-acting somatostatin analogues (SSA) widely used in patients with pancreatic neuroendocrine tumours (P-NETs). A subset of patients is resistant to SSA, although the molecular mechanisms responsible for resistance are poorly understood. Several studies identified cytoskeleton protein interactions as determinant in receptor anchoring, expression and signalling. Since SST2 was recently demonstrated to a...

cAMP is an ubiquitous second messenger that is implicated in the regulation of a wide variety of cell functions, including cell proliferation that is differently affected depending on the cell type. Although the effects exerted by cAMP were initially attributed to PKA activation, two exchange proteins directly activated by cAMP (Epac1/2) have been identified as cAMP targets able to mediate several cAMP effects. Aim of this study was to investigate the effect of cAMP on neuroen...