Ca²⁺ Channel Toolkit in Neuroendocrine Tumors

Abstract

Neuroendocrine tumors (NET) constitute a heterogeneous group of malignancies with various clinical presentations and growth rates but a common origin in neuroendocrine cells located all over the body. NET are a relatively low-frequency disease mostly represented by gastroenteropancreatic (GEP) and bronchopulmonary tumors (pNET); on the other hand, an increasing frequency and prevalence have been associated with NET. Despite great efforts in recent years, the management of NET is still a critical unmet need due to the lack of knowledge of the biology of the disease, the lack of adequate biomarkers, late presentation, the relative insensitivity of imaging modalities, and a paucity of predictably effective treatment options. In this context Ca2+ signals, being pivotal molecular devices in sensing and integrating signals from the microenvironment, are emerging to be particularly relevant in cancer, where they mediate interactions between tumor cells and the tumor microenvironment to drive different aspects of neoplastic progression (e.g., cell proliferation and survival, cell invasiveness, and proangiogenetic programs). Indeed, ion channels represent good potential pharmacological targets due to their location on the plasma membrane, where they can be easily accessed by drugs. The present review aims to provide a critical and up-to-date overview of NET development integrating Ca2+ signal involvement. In this perspective, we first give an introduction to NET and Ca2+ channels and then describe the different families of Ca2+ channels implicated in NET, i.e., ionotropic receptors, voltage-dependent Ca2+ channels, and transient receptor potential channels, as well as intracellular Ca2+ channels and their signaling molecules.

Metal Ions in Cancer Prevention and Treatment with Traditional Chinese Medicine

“…This article mainly outlines the role of metal ions in the anti-tumor of TCM, but some ion receptors also deserve our attention. The receptors can be classified into ion channel receptors [149][150][151][152][153][154] , G protein-coupled receptors [155][156] , hormone-like receptors [149,157] , etc, according to their mechanism, such as protein structure, information transduction process, and nature of effect. These receptors have been reported to be able to influence pathophysiological states in a variety of diseases, such as neurological disorders [149][150][151][152] , cancer [152][153][154][155][156] , hypertension [157] , and vascular aging [149] .…”

“…The receptors can be classified into ion channel receptors [149][150][151][152][153][154] , G protein-coupled receptors [155][156] , hormone-like receptors [149,157] , etc, according to their mechanism, such as protein structure, information transduction process, and nature of effect. These receptors have been reported to be able to influence pathophysiological states in a variety of diseases, such as neurological disorders [149][150][151][152] , cancer [152][153][154][155][156] , hypertension [157] , and vascular aging [149] . It is worth noting that although studies have shown that some receptors have therapeutic potential in anti-tumor, but whether they can become drug targets for cancer treatment is still unclear.…”

Prognostic role of hERG1 Potassium Channels in Neuroendocrine Tumours of the Ileum and Pancreas

“…To fill this gap, we have studied a novel class of cancer biomarkers, i.e., ion channel proteins. The expression and role of calcium channels in NETs have been elucidated (see [36] for a comprehensive review), and the large-conductance Ca 2+ -activated K + channel (BK Ca ) is expressed in the human somatostatinoma QGP-1 cell line and that the regulatory γ1 subunit promotes cell proliferation [37]. However, to the best of our knowledge, no data have been published about hERG1 expression and clinical significance in human neuroendocrine tumours.…”