Citations

Signaling via release of Ca2+from intracellular stores is mediated by several systems, including the inositol 1,4,5-trisphosphate (IP3) and cADP-ribose (cADPR) pathway. We recently discovered a high capacity for cADPR synthesis in rat glomeruli and cultured mesangial cells (MC). We sought to determine whether 1) cADPR synthesis in MC is regulated by cytokines and hormones, 2) ryanodine receptors (RyRs) are expressed in MC, and 3) Ca2+is released through RyRs in response to cADPR. We found that ADP-ribosyl cyclase, a CD38-like enzyme that catalyzes cADPR synthesis, is upregulated in MC by tumor necrosis factor-α, interleukin-1β, and all- trans retinoic acid (atRA). [3H]ryanodine binds to microsomal fractions from MC with high affinity in a Ca2+-dependent manner; binding is enhanced by specific RyR agonists and blocked by ruthenium red and cADPR. Western blot analysis confirmed the presence of RyR in MC. Release of45Ca2+from MC microsomes was stimulated by cADPR; release was blocked by ruthenium red and 8-bromo-cADPR. ADPR (non-cyclic) was without effect. In MC, TNF-α and atRA amplified the increment of cytoplasmic Ca2+elicited by vasopressin. We conclude that MC possess elements of a novel ADP-ribosyl cyclase→cADPR→RyR→Ca2+-release signaling pathway subject to regulation by proinflammatory cytokines and steroid superfamily hormones.

Background— We explored regional variation in 30-day ischemic stroke mortality and readmission rates and the extent to which regional differences in patients, hospitals, healthcare resources, and a quality of care composite care measure explain the observed variation. Methods and Results— This ecological analysis aggregated patient and hospital characteristics from the Get With The Guidelines–Stroke registry (2007–2011), healthcare resource data from the Dartmouth Atlas of Health Care (2006), and Medicare fee-for-service data on 30-day mortality and readmissions (2007–2011) to the hospital referral region (HRR) level. We used linear regression to estimate adjusted HRR-level 30-day outcomes, to identify HRR-level characteristics associated with 30-day outcomes, and to describe which characteristics explained variation in 30-day outcomes. The mean adjusted HRR-level 30-day mortality and readmission rates were 10.3% (SD=1.1%) and 13.1% (SD=1.1%), respectively; a modest, negative correlation ( r =−0.17; P =0.003) was found between one another. Demographics explained more variation in readmissions than mortality (25% versus 6%), but after accounting for demographics, comorbidities accounted for more variation in mortality compared with readmission rates (17% versus 7%). The combination of hospital characteristics and healthcare resources explained 11% and 16% of the variance in mortality and readmission rates, beyond patient characteristics. Most of the regional variation in mortality (65%) and readmission (50%) rates remained unexplained. Conclusions— Thirty-day mortality and readmission rates vary substantially across HRRs and exhibit an inverse relationship. While regional variation in 30-day outcomes were explained by patient and hospital factors differently, much of the regional variation in both outcomes remains unexplained.

Abstract Metastatic melanoma (MM) is the most aggressive type of skin cancer contributing to approximately 80% of all skin cancer related deaths. In 2016, it was estimated that more 76,000 cases would be diagnosed in the United States. The high metastatic potential and aggressive clinical behavior of this disease makes it a major health problem. As a consequence there has been notable development in for novel targeted (i.e. BRAF inhibitors) and immune therapies (i.e. anti-PD1 and CTLA4 inhibitors). However, despite improvements in patient outcomes, most patients develop resistance within 6-11 months on dual BRAF/MEK inhibition, and 5 months on immune therapy, highlighting the need to identify new therapies that improve disease management and patient survival. Increased expression of CyclinD1 has been reported to occur as a mechanism of resistance to BRAF inhibition, resulting in reactivation of the canonical activating pathway in melanoma, MAPK. Thus, we hypothesize that combined inhibition of CDK4/6 and MAPK signaling will provide a novel anti-tumor synergy drug combination superior to current standard of care in BRAF mutant patient-derived preclinical models. Using MM human tissue from patients we developed 3 BRAF mutant preclinical models investigating a novel triple therapy drug combination BRAFi/MEKi/CDK4/6i. Protein analysis and drug proliferation assays were used to design the novel combination. In vivo, we found statistically significant differences in tumor inhibition between the novel combination and the current standard of care. The triple therapy also showed promising results, in vivo, when assessed as a salvage therapy following tumor escape from BRAFi/MEKi combination treatment. Citation Format: Antoneicka L. Harris, Michael Thompson, Svetomir Markovic, William Durham, Louis Dawson, Daniel Small, John A. Copland. Tumor regression in novel triple therapy BRAF mutant metastatic melanoma patient-derived preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-130. doi:10.1158/1538-7445.AM2017-LB-130

The release of Ca2+ from intracellular stores is a fundamental element of signaling pathways involved in regulation of vascular tone, proliferation, apoptosis, and gene expression. Studies of sea urchin eggs have led to the identification of three functionally distinct Ca2+ signaling pathways triggered by IP3, cADPR, and NAADP. The coexistence and functional relevance of these distinct intracellular Ca2+ release systems has only been described in a few mammalian cell types. The purpose of this study was to determine whether the IP3, cADPR, and NAADP Ca2+ release systems coexist in smooth muscle cells (SMC) and to determine the specificity of these intracellular Ca2+ release pathways. Microsomes were prepared from rat aortic SMC (VSMC) and were loaded with 45Ca2+. cADPR, NAADP, and IP3 induced Ca2+ release from VSMC microsomes in a dose-dependent fashion. Heparin blocked only IP3-mediated Ca2+ release, whereas the ryanodine channel inhibitors 8-Br-cADPR and ruthenium red blocked only cADPR-induced Ca2+ release. Nifedipine, an L-type Ca2+ channel blocker, inhibited NAADP elicited Ca2+ release, but had no effect on IP3- or cADPR-mediated Ca2+ release. An increase in pH from 7.2 to 8.2 inhibited cADPR-mediated Ca2+ release, but had no effect on IP3- or NAADP-induced Ca2+ release. By RT-PCR, VSMC expressed ryanodine receptor types 1, 2, and 3. Ca2+-dependent binding of [3H]-ryanodine to VSMC microsomes was enhanced by the ryanodine receptor agonists 4-chloro-methyl-phenol (CMP) and caffeine, but was inhibited by ruthenium red and cADPR. We conclude that VSMC possess at least three functionally distinct pathways that promote intracellular Ca2+ release. IP3-, cADPR-, and NAADP-induced intracellular Ca2+ release may play a critical role in the maladaptive responses of VSMC to environmental stimuli that are characteristically associated with hypertension and/or atherogenesis.

Polycystic kidney diseases (PKD) are characterized by excessive proliferation of renal tubular epithelial cells, development of fluid-filled cysts, and progressive renal insufficiency. cAMP inhibits proliferation of normal renal tubular epithelial cells but stimulates proliferation of renal tubular epithelial cells derived from patients with PKD. Madin-Darby canine kidney (MDCK) epithelial cells, which are widely used as an in vitro model of cystogenesis, also proliferate in response to cAMP. Intracellular cAMP levels are tightly regulated by phosphodiesterases (PDE). Isoform-specific PDE inhibitors have been developed as therapeutic agents to regulate signaling pathways directed by cAMP. In other renal cell types, we have previously demonstrated that cAMP is hydrolyzed by PDE3 and PDE4, but only PDE3 inhibitors suppress proliferation by inhibiting Raf-1 activity (Cheng J, Thompson MA, Walker HJ, Gray CE, Diaz Encarnacion MM, Warner GM, Grande JP. Am J Physiol Renal Physiol 287:F940-F953, 2004.) A potential role for PDE isoform(s) in cAMP-mediated proliferation of MDCK cells has not previously been established. Similar to what we have previously found in several other renal cell types, cAMP hydrolysis in MDCK cells is directed primarily by PDE4 (85% of total activity) and PDE3 (15% of total activity). PDE4 inhibitors are more effective than PDE3 inhibitors in increasing intracellular cAMP levels in MDCK cells. However, only PDE3 inhibitors, and not PDE4 inhibitors, stimulate mitogenesis of MDCK cells. PDE3 but not PDE4 inhibitors activate B-Raf but not Raf-1, as assessed by an in vitro kinase assay. PDE3 but not PDE4 inhibitors activate the ERK pathway and activate cyclins D and E, as assessed by histone H1 kinase assay. We conclude that mitogenesis of MDCK cells is regulated by a functionally compartmentalized intracellular cAMP pool directed by PDE3. Pharmacologic agents that stimulate PDE3 activity may provide the basis for new therapies directed toward reducing cystogenesis in patients with PKD.

Airway remodeling in asthma driven by inflammation involves proliferation of epithelial cells and airway smooth muscle (ASM), as well as enhanced extracellular matrix (ECM) generation and deposition, i.e., fibrosis. Accordingly, understanding profibrotic mechanisms is important for developing novel therapeutic strategies in asthma. Recent studies, including our own, have suggested a role for locally produced growth factors such as brain-derived neurotrophic factor (BDNF) in mediating and modulating inflammation effects. In this study, we explored the profibrotic influence of BDNF in the context of asthma by examining expression, activity, and deposition of ECM proteins in primary ASM cells isolated from asthmatic vs. nonasthmatic patients. Basal BDNF expression and secretion, and levels of the high-affinity BDNF receptor TrkB, were higher in asthmatic ASM. Exogenous BDNF significantly increased ECM production and deposition, especially of collagen-1 and collagen-3 (less so fibronectin) and the activity of matrix metalloproteinases (MMP-2, MMP-9). Exposure to the proinflammatory cytokine TNFα significantly increased BDNF secretion, particularly in asthmatic ASM, whereas no significant changes were observed with IL-13. Chelation of BDNF using TrkB-Fc reversed TNFα-induced increase in ECM deposition. Conditioned media from asthmatic ASM enhanced ECM generation in nonasthmatic ASM, which was blunted by BDNF chelation. Inflammation-induced changes in MMP-2, MMP-9, and tissue inhibitor metalloproteinases (TIMP-1, TIMP-2) were reversed in the presence of TrkB-Fc. These novel data suggest ASM as an inflammation-sensitive source of BDNF within human airways, with autocrine effects on fibrosis relevant to asthma.

Purpose: The use of social media, in particular Twitter, has substantially increased among health care stakeholders in the field of hematology and oncology, with an especially sharp increase in the use of Twitter during times of major national meetings. The most attended meeting in the oncology field is the ASCO annual meeting. Little is known about the detailed metrics involved in the use, volume, and impact of Twitter during the ASCO annual meeting. Methods: We conducted a retrospective review of tweets during the ASCO annual meetings from 2011 to 2016. The total data set encompassed 190,732 tweets from 39,745 authors over six consecutive ASCO meetings from 2011 to 2016 (inclusive). Tweets, all publically available, were collected by Nephrology On-Demand Analytics. Results: The number of individual authors increased from 1,429 during the 2011 ASCO meeting to 15,796 during the 2016 ASCO meeting, an 11-fold increase over the total 5-year period. There was a notable increase in tweets from the 2011 ASCO meeting (n = 7,746) to the 2016 ASCO meeting (n = 72,698), a nine-fold increase during the study period. The most commonly tweeted term or topic changed over time, generally reflecting the breakthroughs of each designated year; these terms were “melanoma” for both the 2011 and 2012 ASCO meetings; “breast cancer” for the 2013 ASCO meeting; “lung cancer” for the 2014 ASCO meeting; and “ImmunOnc” or “immunotherapy/immuno-oncology” for both the 2015 and 2016 ASCO meetings. Conclusion: The use of Twitter among health care stakeholders during the ASCO meeting has markedly increased over time, demonstrating the increasing role of social media in the dissemination of findings at the most highly attended hematology and oncology conference of the year.

In airway smooth muscle (ASM) cells, excitation-contraction coupling is accomplished via a cascade of events that connect an elevation of cytosolic Ca2+concentration ([Ca2+]cyt) with cross-bridge attachment and ATP-consuming mechanical work. Excitation-energy coupling is mediated by linkage of the elevation of [Ca2+]cytto an increase in mitochondrial Ca2+concentration, which in turn stimulates ATP production. Proximity of mitochondria to the sarcoplasmic reticulum (SR) and plasma membrane is thought to be an important mechanism to facilitate mitochondrial Ca2+uptake. In this regard, mitochondrial movement in ASM cells may be key in establishing proximity. Mitochondria also move where ATP or Ca2+buffering is needed. Mitochondrial movement is mediated through interactions with the Miro-Milton molecular complex, which couples mitochondria to kinesin motors at microtubules. We examined mitochondrial movement in human ASM cells and hypothesized that, at basal [Ca2+]cytlevels, mitochondrial movement is necessary to establish proximity of mitochondria to the SR and that, during the transient increase in [Ca2+]cytinduced by agonist stimulation, mitochondrial movement is reduced, thereby promoting transient mitochondrial Ca2+uptake. We further hypothesized that airway inflammation disrupts basal mitochondrial movement via a reduction in Miro and Milton expression, thereby disrupting the ability of mitochondria to establish proximity to the SR and, thus, reducing transient mitochondrial Ca2+uptake during agonist activation. The reduced proximity of mitochondria to the SR may affect establishment of transient “hot spots” of higher [Ca2+]cytat the sites of SR Ca2+release that are necessary for mitochondrial Ca2+uptake via the mitochondrial Ca2+uniporter.

Purpose: The Conquer Cancer Foundation (CCF), the philanthropic arm of ASCO, is responsible for funding innovative clinical research. CCF wants to broaden its donor base instead of relying predominantly on health-care companies. Our Leadership Development Program (LDP) group was tasked with identifying potential donor sources and making recommendations to increase funding. Materials and Methods: We selected three sources to research: the general public, crowdsourcing/social media, and ASCO members. We subsequently focused our efforts on ASCO members, of whom only 2% to 3% are donors to CCF and < 8% are repeat donors. To analyze this low rate, we sent out two separate surveys to various groups of members within ASCO. Results: We identified lack of knowledge as a major deterrent to giving; surprisingly, even those who hold ASCO leadership positions or participated in committees lacked knowledge about CCF funding. Also, the misconception that ASCO is rich and does not need philanthropic support deterred giving; however, respondents would donate if given the right message that stresses the need of continued member-led donations. Conclusion: ASCO members, including those in leadership positions, need to be engaged more aggressively to support CCF. Increased education and updating the CCF message is likely to provide the greatest impact on higher member donation, repeated donations, and facilitate CCF’s goal of diversifying its donor base away from healthcare companies. Furthermore, we recommend using technology, such as mobile applications, and providing incentives and visibility to major donors.

Skin cancer affects more individuals in the USA than any other malignancy and malignant melanoma is particularly deadly because of its metastatic potential. Melanoma has been recognized as one of the most immunogenic malignancies; therefore, understanding the mechanisms of tumor–immune interaction is key for developing more efficient treatments. As the tumor microenvironment shows an immunosuppressive action, immunotherapeutic agents promoting endogenous immune response to cancer have been tested (interleukin-2, anticytotoxic-T-lymphocyte-associated antigen 4, and antiprogrammed cell death protein 1 monoclonal antibodies) as well as combinations of cytotoxic chemotherapy agents and inhibitors of angiogenesis (taxol/carboplatin/avastin). However, clinical outcomes are variable, with only a minority of patients achieving durable complete responses. The variability of immune homeostasis, which may be more active or more tolerant at any given time, in cancer patients and the interaction of the immune system with the tumor could explain the inconsistency in clinical outcomes among these patients. Recently, the role of the lymphocyte-to-monocyte-ratio (LMR) in the peripheral blood has been investigated and has been proven to be an independent predictor of survival in different hematological malignancies and in solid tumors. In melanoma, our group has validated the significance of LMR as a predictor of relapse after resection of advanced melanoma. In this study, we examined the dynamics in the immune system of patients with advanced melanoma by performing serial multiday concentration measurements of cytokines and immune cell subsets in the peripheral blood. The analysis of outcomes of chemotherapy administration as related to LMR on the day of treatment initiation showed that progression-free survival was improved in the patients who received chemotherapy on the day when LMR was elevated.