GPR68-ATF4 signaling is a novel prosurvival pathway in glioblastoma activated by acidic extracellular microenvironment.

BACKGROUND: Glioblastoma multiforme (GBM) stands as a formidable challenge in oncology because of its aggressive nature and severely limited treatment options. Despite decades of research, the survival rates for GBM remain effectively stagnant. A defining hallmark of GBM is a highly acidic tumor microenvironment, which is thought to activate pro-tumorigenic pathways. This acidification is the result of altered tumor metabolism favoring aerobic glycolysis, a phenomenon known as the Warburg effect. Low extracellular pH confers radioresistant tumors to glial cells. Notably GPR68, an acid sensing GPCR, is upregulated in radioresistant GBM. Usage of Lorazepam, which has off target agonism of GPR68, is linked to worse clinical outcomes for a variety of cancers. However, the role of tumor microenvironment acidification in GPR68 activation has not been assessed in cancer. Here we interrogate the role of GPR68 specifically in GBM cells using a novel highly specific small molecule inhibitor of GPR68 named Ogremorphin (OGM) to induce the iron mediated cell death pathway: ferroptosis. METHOD: OGM was identified in a non-biased zebrafish embryonic development screen and validated with Morpholino and CRISPR based approaches. Next, A GPI-anchored pH reporter, pHluorin2, was stably expressed in U87 glioblastoma cells to probe extracellular acidification. Cell survival assays, via nuclei counting and cell titer glo, were used to demonstrate sensitivity to GPR68 inhibition in twelve immortalized and PDX GBM lines. To determine GPR68 inhibition's mechanism of cell death we use DAVID pathway analysis of RNAseq. Our major indication, ferroptosis, was then confirmed by western blotting and qRT-PCR of reporter genes including TFRC. This finding was further validated by transmission electron microscopy and liperfluo staining to assess lipid peroxidation. Lastly, we use siRNA and CRISPRi to demonstrate the critical role of ATF4 suppression via GPR68 for GBM survival. RESULTS: We used a pHLourin2 probe to demonstrate how glioblastoma cells acidify their microenvironment to activate the commonly over expressed acid sensing GPCR, GPR68. Using our small molecule inhibitor OGM and genetic means, we show that blocking GPR68 signaling results in robust cell death in all thirteen glioblastoma cell lines tested, irrespective of genetic and phenotypic heterogeneity, or resistance to the mainstay GBM chemotherapeutic temozolomide. We use U87 and U138 glioblastoma cell lines to show how selective induction of ferroptosis occurs in an ATF4-dependent manner. Importantly, OGM was not-acutely toxic to zebrafish and its inhibitory effects were found to spare non-malignant neural cells. CONCLUSION: These results indicate GPR68 emerges as a critical sensor for an autocrine pro-tumorigenic signaling cascade triggered by extracellular acidification in glioblastoma cells. In this context, GPR68 suppresses ATF4, inhibition of GPR68 increases expression of ATF4 which leads to ferroptotic cell death. These findings provide a promising therapeutic approach to selectively induce ferroptosis in glioblastoma cells while sparing healthy neural tissue.

Invasive Multimodality Neuromonitoring to Manage Cerebral Edema in Pediatric Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease.

Background: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an inflammatory disorder of the CNS with a variety of clinical manifestations, including cerebral edema. Case Summary: A 7-year-old boy presented with headaches, nausea, and somnolence. He was found to have cerebral edema that progressed to brainstem herniation. Invasive multimodality neuromonitoring was initiated to guide management of intracranial hypertension and cerebral hypoxia while he received empiric therapies for neuroinflammation. Workup revealed serum myelin oligodendrocyte glycoprotein antibodies. He survived with a favorable neurologic outcome. Conclusion: We describe a child who presented with cerebral edema and was ultimately diagnosed with MOGAD. Much of his management was guided using data from invasive multimodality neuromonitoring. Invasive multimodality neuromonitoring may have utility in managing life-threatening cerebral edema due to neuroinflammation.

Dramatic Response to Anti-IL-6 Receptor Therapy in Children With Life-Threatening Myelin Oligodendrocyte Glycoprotein-Associated Disease.

OBJECTIVES: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an immune-mediated neuroinflammatory disorder leading to demyelination of the CNS. Interleukin (IL)-6 receptor blockade is under study in relapsing MOGAD as a preventative strategy, but little is known about the role of such treatment for acute MOGAD attacks. METHODS: We discuss the cases of a 7-year-old boy and a 15-year-old adolescent boy with severe acute CNS demyelination and malignant cerebral edema with early brain herniation associated with clearly positive serum titers of MOG-IgG, whose symptoms were incompletely responsive to standard acute therapies (high-dose steroids, IV immunoglobulins (IVIGs), and therapeutic plasma exchange). RESULTS: Both boys improved quickly with IL-6 receptor inhibition, administered as tocilizumab. Both patients have experienced remarkable neurologic recovery. DISCUSSION: We propose that IL-6 receptor therapies might also be considered in acute severe life-threatening presentations of MOGAD.

Expression of LIM domain-binding 3 (LDB3), a striated muscle Z-band alternatively spliced PDZ-motif protein in the nervous system.

LIM domain-binding 3 (LDB3) is a member of the Enigma family of PDZ-LIM proteins. LDB3 has been reported as a striated muscle-specific Z-band alternatively spliced protein that plays an important role in mechanosensory actin cytoskeleton remodeling. This study shows that LDB3 is broadly expressed in the central and peripheral nervous system of human and mouse. LDB3 is predominantly expressed in the adult stages compared to early development and at a significantly higher level in the spinal cord than in the brain. As in skeletal muscle and heart, LDB3 is extensively alternatively spliced in the neurons. Three novel splice isoforms were identified suggesting splicing-dependent regulation of LDB3 expression in the nervous system. Expression of LDB3 in the motor cortex, cerebellum, spinal motor neuron, peripheral nerve, and neuromuscular junction in addition to skeletal muscle indicates important roles for this PDZ-LIM family protein in motor planning and execution. Moreover, expression in the hippocampal neurons suggests roles for LDB3 in learning and memory. LDB3 interactors filamin C and myotilin are also expressed in the spinal motor neuron, nerve, and neuromuscular junction, thereby providing the basis for neurogenic manifestations in myopathies associated with mutations in these so-called muscle proteins.

Well Water and Parkinson's Disease in Medicare Beneficiaries: A Nationwide Case-Control Study.

BACKGROUND: Well water frequently is considered a risk factor for Parkinson's disease (PD), but few studies were designed appropriately to test whether geographic factors affect PD risk. OBJECTIVE: To determine the risk of PD in relation to residential use of private well water. METHODS: In a nationwide, population-based case-control study, we identified all incident PD cases (N = 89,790) and all comparable controls (N = 21,549,400) age 66-90 who solely relied on Medicare coverage in the U.S. in 2009. We estimated the probability of use of private well water using zip code of residence at diagnosis/reference and U.S. Census data on household water source. We modeled this exposure linearly in logistic regression to calculate the odds ratio (OR) and 95% confidence interval (CI) of PD risk in relation to well water use. We adjusted for age, sex and race/ethnicity, and verified that smoking and use of medical care did not confound results. We repeated analyses with a 2-year exposure lag and separately within each U.S. state. RESULTS: Use of well water was inversely associated with PD risk (OR = 0.87, 95% CI 0.85-0.89). We confirmed this association in a Cox survival analysis in which we followed controls for 5 years, death or PD diagnosis. There was little evidence that well water use increased risk of PD in any individual state. CONCLUSIONS: Although it remains possible that exposures in well water in more narrow geographic regions increase PD risk, in general these results suggest that exposures more common in urban/suburban areas might also be relevant.

Global public health impact of recovered supplies from operating rooms: a critical analysis with national implications.

BACKGROUND: In modern operating rooms, clean and unused medical supplies are routinely discarded and can be effectively recovered and redistributed abroad to alleviate the environmental burden of donor hospitals and to generate substantial health benefits at resource-poor recipient institutions. METHODS: We established a recovery and donation program to collect clean and unused supplies for healthcare institutions in developing nations. We analyzed items donated over a 3-year period (September 2010-November 2013) by quantity and weight, and estimated the projected value of the program under potential nationwide participation. To capture the health benefits attributable to the donated supplies at recipient institutions, we partnered with two tertiary-care centers in Guayaquil, Ecuador and conducted a pilot study on the utility of the donated supplies at the recipient institutions (October 2013). We determined the disability-adjusted life years (DALY) averted for all patients undergoing procedures involving donated items and estimated the annual attributable DALY as well as the cost per DALY averted both by supply and by procedure. RESULTS: Approximately, 2 million lbs (907,185 kg) per year of medical supplies are recoverable from large non-rural US academic medical centers. Of these supplies, 19 common categories represent a potential for donation worth US $15 million per year, at a cost-utility of US $2.14 per DALY averted. CONCLUSIONS: Hospital operating rooms continue to represent a large source of recoverable surgical supplies that have demonstrable health benefits in the recipient communities. Cost-effective recovery and need-based donation programs can significantly alleviate the global burden of surgical diseases.

NCCN roundtable: talking to children about cancer.

A roundtable presentation at the NCCN 19th Annual Conference focused on the child's experience when a parent has cancer and concluded that honest communication, appropriate to the child's age and temperament, is essential, and that oncology providers should institute programs that help families deal with the illness.