Screening Ion Channels in Cancer Cells.

Ion channels are critical for cell development and maintaining cell homeostasis. The perturbation of ion channel function contributes to the development of a broad range of disorders or channelopathies. Cancer cells utilize ion channels to drive their own development, as well as to improve as a tumor and to assimilate in a microenvironment that includes various non-cancerous cells. Furthermore, increases in levels of growth factors and hormones within the tumor microenvironment can result in enhanced ion channel expression, which contributes to cancer cell proliferation and survival. Thus, the pharmacological targeting of ion channels is potentially a promising approach to treating solid malignancies, including primary and metastatic brain cancers. Herein, protocols to characterize the function of ion channels in cancerous cells and approaches to analyze modulators of ion channels to determine their impact on cancer viability are described. These include staining a cell(s) for an ion channel(s), testing the polarized state of mitochondria, establishing ion channel function using electrophysiology, and performing viability assays to assess drug potency.

GABA(A) receptor activation drives GABARAP-Nix mediated autophagy to radiation-sensitize primary and brain-metastatic lung adenocarcinoma tumors.

In non-small cell lung cancer (NSCLC) treatment, targeted therapies benefit only a subset of NSCLC, while radiotherapy responses are not durable and toxicity limits therapy. We find that a GABA(A) receptor activator, AM-101, impairs viability and clonogenicity of NSCLC primary and brain metastatic cells. Employing an ex vivo 'chip', AM-101 is as efficacious as the chemotherapeutic docetaxel, which is used with radiotherapy for advanced-stage NSCLC. In vivo , AM-101 potentiates radiation, including conferring a survival benefit to mice bearing NSCLC intracranial tumors. GABA(A) receptor activation stimulates a selective-autophagic response via multimerization of GABA(A) Receptor-Associated Protein (GABARAP), stabilization of mitochondrial receptor Nix, and utilization of ubiquitin-binding protein p62. A targeted-peptide disrupting Nix binding to GABARAP inhibits AM-101 cytotoxicity. This supports a model of GABA(A) receptor activation driving a GABARAP-Nix multimerization axis triggering autophagy. In patients receiving radiotherapy, GABA(A) receptor activation may improve tumor control while allowing radiation dose de-intensification to reduce toxicity. Highlights: Activating GABA(A) receptors intrinsic to lung primary and metastatic brain cancer cells triggers a cytotoxic response. GABA(A) receptor activation works as well as chemotherapeutic docetaxel in impairing lung cancer viability ex vivo . GABA(A) receptor activation increases survival of mice bearing lung metastatic brain tumors.A selective-autophagic response is stimulated by GABA(A) receptor activation that includes multimerization of GABARAP and Nix.Employing a new nanomolar affinity peptide that abrogates autophagosome formation inhibits cytotoxicity elicited by GABA(A) receptor activation.

Ligand-Gated Ion Channels as Targets for Treatment and Management of Cancers.

Ligand-gated ion channels are an ionotropic receptor subtype characterized by the binding of an extracellular ligand, followed by the transient passage of ions through a transmembrane pore. Ligand-gated ion channels are commonly subcategorized into three superfamilies: purinoreceptors, glutamate receptors, and Cys-loop receptors. This classification is based on the differing topographical morphology of the receptors, which in turn confers functional differences. Ligand-gated ion channels have a diverse spatial and temporal expression which implicate them in key cellular processes. Given that the transcellular electrochemical gradient is finely tuned in eukaryotic cells, any disruption in this homeostasis can contribute to aberrancies, including altering the activity of pro-tumorigenic molecular pathways, such as the MAPK/ERK, RAS, and mTOR pathways. Ligand-gated ion channels therefore serve as a potential targetable system for cancer therapeutics. In this review, we analyze the role that each of the three ligand-gated ion channel superfamilies has concerning tumor proliferation and as a target for the treatment of cancer symptomatology.

Advances in Immunotherapy for the Treatment of Adult Glioblastoma: Overcoming Chemical and Physical Barriers.

Glioblastoma, or glioblastoma multiforme (GBM, WHO Grade IV), is a highly aggressive adult glioma. Despite extensive efforts to improve treatment, the current standard-of-care (SOC) regimen, which consists of maximal resection, radiotherapy, and temozolomide (TMZ), achieves only a 12-15 month survival. The clinical improvements achieved through immunotherapy in several extracranial solid tumors, including non-small-cell lung cancer, melanoma, and non-Hodgkin lymphoma, inspired investigations to pursue various immunotherapeutic interventions in adult glioblastoma patients. Despite some encouraging reports from preclinical and early-stage clinical trials, none of the tested agents have been convincing in Phase III clinical trials. One, but not the only, factor that is accountable for the slow progress is the blood-brain barrier, which prevents most antitumor drugs from reaching the target in appreciable amounts. Herein, we review the current state of immunotherapy in glioblastoma and discuss the significant challenges that prevent advancement. We also provide thoughts on steps that may be taken to remediate these challenges, including the application of ultrasound technologies.

The leaf extract of Spondias mombin L. displays an anti-inflammatory effect and suppresses inducible formation of tumor necrosis factor-α and nitric oxide (NO).

Extracts of Spondias mombin L. (Anacardiacea) is used in the traditional medicine of Africa and Latin America to treat many inflammatory conditions, with repeated claims of efficacy. However, there are no scientific data yet to support these claims and the mechanism through which the extract may be acting is still unknown. This study was undertaken to investigate the effects of the methanolic extract of the leaf of S. mombin (SM) on inflammation and to uncover some of the possible mechanisms that could explain any observed changes. The anti-inflammatory activity of the extract was investigated in Wistar rats using intraplantar injection of carrageenan as an in vivo model of inflammation. The effect of oral supplementation of the SM extract on tumor necrosis factor (TNF)-α levels after an intraperitoneal lipopolysaccharide (LPS; 1 mg/kg) challenge was investigated in mice. The effect of SM on TNF-α and inducible nitric oxide (iNO) production by LPS-stimulated bone marrow-derived macrophages (BM-MØ) was also investigated in vitro. BM-MØ were preincubated for 2 h with SM (0-100 µg/ml), activated with LPS, and then TNF-α and NO production measured in the cell-free conditioned culture supernatant after 24 h of incubation. The study showed that pre-treatment of rats with the SM extract (at 100, 200, and 400 mg/kg, per os) caused a significant dose-related inhibition of carrageenan-induced paw edema over a 4-h period. In treated mice, LPS-inducible (systemic) TNF-α levels were found to be significantly lower as a result of their receiving the SM extract. In vitro, SM treatment caused a dose-dependent decrease in LPS-inducible TNF-α and NO production by BM-MØ compared to the effects of treatment of the cells with LPS alone. Taken together, the results of these studies suggest that supplementation with SM extract can alleviate inflammatory responses and that this could possibly be via a suppression of the production of pro-inflammatory mediators and cytokines such as TNF-α and iNO.