SERCA2a overexpression improves muscle function in a canine Duchenne muscular dystrophy model.

Excessive cytosolic calcium accumulation contributes to muscle degeneration in Duchenne muscular dystrophy (DMD). Sarco/endoplasmic reticulum calcium ATPase (SERCA) is a sarcoplasmic reticulum (SR) calcium pump that actively transports calcium from the cytosol into the SR. We previously showed that adeno-associated virus (AAV)-mediated SERCA2a therapy reduced cytosolic calcium overload and improved muscle and heart function in the murine DMD model. Here, we tested whether AAV SERCA2a therapy could ameliorate muscle disease in the canine DMD model. 7.83 × 1013 vector genome particles of the AAV vector were injected into the extensor carpi ulnaris (ECU) muscles of four juvenile affected dogs. Contralateral ECU muscles received excipient. Three months later, we observed widespread transgene expression and significantly increased SERCA2a levels in the AAV-injected muscles. Treatment improved SR calcium uptake, significantly reduced calpain activity, significantly improved contractile kinetics, and significantly enhanced resistance to eccentric contraction-induced force loss. Nonetheless, muscle histology was not improved. To evaluate the safety of AAV SERCA2a therapy, we delivered the vector to the ECU muscle of adult normal dogs. We achieved strong transgene expression without altering muscle histology and function. Our results suggest that AAV SERCA2a therapy has the potential to improve muscle performance in a dystrophic large mammal.

Dynamic regulation of airway surface liquid pH by TMEM16A and SLC26A4 in cystic fibrosis nasal epithelia with rare mutations.

In cystic fibrosis (CF), defects in the CF transmembrane conductance regulator (CFTR) channel lead to an acidic airway surface liquid (ASL), which compromises innate defence mechanisms, predisposing to pulmonary failure. Restoring ASL pH is a potential therapy for people with CF, particularly for those who cannot benefit from current highly effective modulator therapy. However, we lack a comprehensive understanding of the complex mechanisms underlying ASL pH regulation. The calcium-activated chloride channel, TMEM16A, and the anion exchanger, SLC26A4, have been proposed as targets for restoring ASL pH, but current results are contradictory and often utilise nonphysiological conditions. To provide better evidence for a role of these two proteins in ASL pH homeostasis, we developed an efficient CRISPR-Cas9-based approach to knock-out (KO) relevant transporters in primary airway basal cells lacking CFTR and then measured dynamic changes in ASL pH under thin-film conditions in fully differentiated airway cultures, which better simulate the in vivo situation. Unexpectantly, we found that both proteins regulated steady-state as well as agonist-stimulated ASL pH, but only under inflammatory conditions. Furthermore, we identified two Food and Drug Administration (FDA)-approved drugs which raised ASL pH by activating SLC26A4. While we identified a role for SLC26A4 in fluid absorption, KO had no effect on cyclic adenosine monophosphate (cAMP)-stimulated fluid secretion in airway organoids. Overall, we have identified a role of TMEM16A in ASL pH homeostasis and shown that both TMEM16A and SLC26A4 could be important alternative targets for ASL pH therapy in CF, particularly for those people who do not produce any functional CFTR.

Molecular and Biochemical Assessment of Gene Therapy in the Canine Model of Duchenne Muscular Dystrophy.

Mutations in the dystrophin gene result in Duchenne muscular dystrophy (DMD), a progressive muscle-wasting disease. Adeno-associated virus (AAV) mediated gene replacement, and CRISPR/Cas9-mediated genome editing hold the potential to treat DMD. Molecular and biochemical analyses are essential to determine gene transfer efficiency and therapeutic efficacy. In this chapter, we present a series of methods routinely used in our laboratory to extract and quantify DNA, RNA, and protein in gene therapy studies performed in the canine DMD model.

The Implication of Hinge 1 and Hinge 4 in Micro-Dystrophin Gene Therapy for Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is a fatal muscle disease caused by dystrophin deficiency. Dystrophin consists of the amino terminus, central rod domain with 24 spectrin-like repeats and four hinges (H), cysteine-rich domain, and carboxyl terminus. Several highly abbreviated micro-dystrophins (µDys) are currently in clinical trials. They all carry H1 and H4. In this study, we investigated whether these two hinges are essential for µDy function in murine DMD models. Three otherwise identical µDys were engineered to contain H1 and/or H4 and were named H1/H4 (with both H1 and H4), ΔH1 (without H1), and ΔH4 (without H4). These constructs were packaged in adeno-associated virus serotype-9 and delivered to the tibialis anterior muscle of 3-month-old male mdx4cv mice (1E12 vector genome particles/muscle). Three months later, we detected equivalent µDys expression in total muscle lysate. However, only H1/H4 and ΔH1 showed correct sarcolemmal localization. ΔH4 mainly existed as sarcoplasmic aggregates. H1/H4 and ΔH1, but not ΔH4, fully restored the dystrophin-associated protein complex and significantly improved the specific muscle force. Eccentric contraction-induced force decline was best protected by H1/H4, followed by ΔH1, but not by ΔH4. Next, we compared H1/H4 and ΔH1 in 6-week-old male mdx mice by intravenous injection (1E13 vector genome particles/mouse). Four months postinjection, H1/H4 significantly outperformed ΔH1 in extensor digitorum longus muscle force measurements but two constructs yielded comparable electrocardiography improvements. We conclude that H4 is essential for µDys function and H1 facilitates force production. Our findings will help develop next-generation µDys gene therapy.

Overcoming Cancer Drug Resistance Utilizing PROTAC Technology.

Cancer drug resistance presents a major barrier to continued successful treatment of malignancies. Current therapies inhibiting proteins indicated in cancer progression are consistently found to lose efficacy as a result of acquired drug resistance, often caused by mutated or overexpressed protein targets. By hijacking the cellular ubiquitin-proteasome protein degradation machinery, proteolysis-targeting chimeras (PROTACs) offer an alternative therapeutic modality to cancer treatments with various potential advantages. PROTACs specific for a number of known cancer targets have been developed in the last 5 years, which present new options for remission in patients with previously untreatable malignancies and provide a foundation for future-generation compounds. One notable advantage of PROTACs, supported by evidence from a number of recent studies, is that they can overcome some of the resistance mechanisms to traditional targeted therapies. More recently, some groups have begun researching the use of PROTACs to successfully degrade mutated targets conferring cancer resistance against first-line treatments. In this review, we focus on analyzing the developments in PROTACs geared towards cancer resistance and targets that confer it in the search for new and successful therapies.

Correction to: Real-World Recurrence Rates and Economic Burden in Patients with Resected Early-Stage Melanoma.

The presentation of the numbers of patients in Tables 1 and 3 was adjusted.

Spinal cord injury causes chronic bone marrow failure.

Spinal cord injury (SCI) causes immune dysfunction, increasing the risk of infectious morbidity and mortality. Since bone marrow hematopoiesis is essential for proper immune function, we hypothesize that SCI disrupts bone marrow hematopoiesis. Indeed, SCI causes excessive proliferation of bone marrow hematopoietic stem and progenitor cells (HSPC), but these cells cannot leave the bone marrow, even after challenging the host with a potent inflammatory stimulus. Sequestration of HSPCs in bone marrow after SCI is linked to aberrant chemotactic signaling that can be reversed by post-injury injections of Plerixafor (AMD3100), a small molecule inhibitor of CXCR4. Even though Plerixafor liberates HSPCs and mature immune cells from bone marrow, competitive repopulation assays show that the intrinsic long-term functional capacity of HSPCs is still impaired in SCI mice. Together, our data suggest that SCI causes an acquired bone marrow failure syndrome that may contribute to chronic immune dysfunction.

Real-World Recurrence Rates and Economic Burden in Patients with Resected Early-Stage Melanoma.

INTRODUCTION: Real-world data on recurrence and economic burden in patients with resected early-stage melanoma are limited. The objective of this study was to assess real-world recurrence rates, risk factors for recurrence, and costs of recurrence in patients with resected stage IIB, IIC, or IIIA melanoma in the USA. METHODS: This retrospective analysis included patients with resected stage IIB, IIC, or IIIA melanoma (American Joint Committee on Cancer staging manual, seventh edition) in the Surveillance, Epidemiology, and End Results (SEER) program-Medicare database of the National Cancer Institute. Recurrence rates and healthcare costs (2018 USD) after recurrence were assessed. RESULTS: Two-year recurrence rates for stages IIB, IIC, and IIIA melanoma were 29, 44, and 46%, respectively. In patients with stage IIB or IIC disease, the odds of recurrence were significantly higher in those aged > 75 years [odds ratio (OR) 1.853, 95% confidence interval (CI) 1.416, 2.425], with ulceration (OR 1.771; 95% CI 1.293, 2.425), or with a higher Charlson Comorbidity Index (OR 1.244; 95% CI 1.129, 1.372); however, the odds of recurrence were significantly lower in those with T3 staging (OR 0.522; 95% CI 0.393, 0.695). In those with stage IIIA melanoma, superficial spreading was associated with significantly lower odds of recurrence (OR 0.178; 95% CI 0.053, 0.601). Following recurrence, mean healthcare costs at 1 year were $31,870 for patients with stage IIB or IIC melanoma and $29,224 for those with stage IIIA melanoma. CONCLUSION: The SEER data show that a substantial proportion of adults with early-stage melanoma experience a recurrence within 2 years following resection, resulting in a significant economic burden to the US healthcare system. Dermatologists can distinguish patients with resected early-stage melanoma who are at a high risk for recurrence and consider referrals to medical oncologists for approved adjuvant therapy or enrollment in clinical trials after surgical resection to reduce the recurrence of melanoma.

An international multi-center serum protein electrophoresis accuracy and M-protein isotyping study. Part II: limit of detection and follow-up of patients with small M-proteins.

Background Electrophoretic methods to detect, characterize and quantify M-proteins play an important role in the management of patients with monoclonal gammopathies (MGs). Significant uncertainty in the quantification and limit of detection (LOD) is documented when M-proteins are <10 g/L. Using spiked sera, we aimed to assess the variability in intact M-protein quantification and LOD across 16 laboratories. Methods Sera with normal, hypo- or hyper-gammaglobulinemia were spiked with daratumumab or elotuzumab, with concentrations from 0.125 to 10 g/L (n = 62) along with a beta-migrating sample (n = 9). Laboratories blindly analyzed samples according to their serum protein electrophoresis (SPEP)/isotyping standard operating procedures. LOD and intra-laboratory percent coefficient of variation (%CV) were calculated and further specified with regard to the method (gel/capillary electrophoresis [CZE]), gating strategy (perpendicular drop [PD]/tangent skimming [TS]), isotyping (immunofixation/immunosubtraction [ISUB]) and manufacturer (Helena/Sebia). Results All M-proteins ≥1 g/L were detected by SPEP. With isotyping the LOD was moderately more sensitive than with SPEP. The intensity of polyclonal background had the biggest negative impact on LOD. Independent of the method used, the intra-laboratory imprecision of M-protein quantification was small (mean CV = 5.0%). Low M-protein concentration and high polyclonal background had the strongest negative impact on intra-laboratory precision. All laboratories were able to follow trend of M-protein concentrations down to 1 g/L. Conclusions In this study, we describe a large variation in the reported LOD for both SPEP and isotyping; overall LOD is most affected by the polyclonal immunoglobulin background. Satisfactory intra-laboratory precision was demonstrated. This indicates that the quantification of small M-proteins to monitor patients over time is appropriate, when subsequent testing is performed within the same laboratory.

An international multi-center serum protein electrophoresis accuracy and M-protein isotyping study. Part I: factors impacting limit of quantitation of serum protein electrophoresis.

Background Serum protein electrophoresis (SPEP) is used to quantify the serum monoclonal component or M-protein, for diagnosis and monitoring of monoclonal gammopathies. Significant imprecision and inaccuracy pose challenges in reporting small M-proteins. Using therapeutic monoclonal antibody-spiked sera and a pooled beta-migrating M-protein, we aimed to assess SPEP limitations and variability across 16 laboratories in three continents. Methods Sera with normal, hypo- or hypergammaglobulinemia were spiked with daratumumab, Dara (cathodal migrating), or elotuzumab, Elo (central-gamma migrating), with concentrations from 0.125 to 10 g/L (n = 62) along with a beta-migrating sample (n = 9). Provided with total protein (reverse biuret, Siemens), laboratories blindly analyzed samples according to their SPEP and immunofixation (IFE) or immunosubtraction (ISUB) standard operating procedures. Sixteen laboratories reported the perpendicular drop (PD) method of gating the M-protein, while 10 used tangent skimming (TS). A mean percent recovery range of 80%-120% was set as acceptable. The inter-laboratory %CV was calculated. Results Gamma globulin background, migration pattern and concentration all affect the precision and accuracy of quantifying M-proteins by SPEP. As the background increases, imprecision increases and accuracy decreases leading to overestimation of M-protein quantitation especially evident in hypergamma samples, and more prominent with PD. Cathodal migrating M-proteins were associated with less imprecision and higher accuracy compared to central-gamma migrating M-proteins, which is attributed to the increased gamma background contribution in M-proteins migrating in the middle of the gamma fraction. There is greater imprecision and loss of accuracy at lower M-protein concentrations. Conclusions This study suggests that quantifying exceedingly low concentrations of M-proteins, although possible, may not yield adequate accuracy and precision between laboratories.

EGFL7 Antagonizes NOTCH Signaling and Represents a Novel Therapeutic Target in Acute Myeloid Leukemia.

PURPOSE: EGF-like domain 7 (EGFL7) is a secreted protein and recently has been shown to play an important role in acute myeloid leukemia (AML); however, the underlying mechanism by which EGFL7 promotes leukemogenesis is largely unknown. EXPERIMENTAL DESIGN: Using an antibody interaction array, we measured the ability of EGFL7 to bind directly approximately 400 proteins expressed by primary AML blasts. Primary patient samples were stimulated in vitro with recombinant EGFL7 (rEGFL7) or anti-EGFL7 blocking antibody to assess alterations in downstream signaling and the ability to effect blast differentiation and survival. We treated three independent AML models with anti-EGFL7 or IgG1 control to determine whether anti-EGFL7 could prolong survival in vivo. RESULTS: We found EGFL7 significantly binds several signaling proteins important for normal and malignant hematopoiesis including NOTCH. Stimulation of AML blasts with rEGFL7 reduced NOTCH intracellular domain and NOTCH target gene expression while treatment with an anti-EGFL7 blocking antibody resulted in reactivation of NOTCH signaling, increased differentiation, and apoptosis. Competitive ligand-binding assays showed rEGFL7 inhibits DELTA-like (DLL) 4-mediated NOTCH activation while anti-EGFL7 combined with DLL4 significantly increased NOTCH activation and induced apoptosis. Using three different AML mouse models, we demonstrated that in vivo treatment with anti-EGFL7 alone results in increased survival. CONCLUSIONS: Our data demonstrate that EGFL7 contributes to NOTCH silencing in AML by antagonizing canonical NOTCH ligand binding. Reactivation of NOTCH signaling in vivo using anti-EGFL7 results in prolonged survival of leukemic mice, supporting the use of EGFL7 as a novel therapeutic target in AML.

Controlled Delivery of Dutasteride Using Dissolvable Microarrays: Initial Formulation and In Vivo Evaluation.

Dutasteride is prescribed as a once-daily oral capsule for the treatment of symptomatic benign prostatic hyperplasia. As an alternative and patient-focused drug product, this laboratory evaluated the potential to deliver dutasteride in a controlled/sustained manner when formulated as a microarray. The low oral dose, low aqueous solubility, and slow rate of elimination of dutasteride were considered ideal properties which may enable a once-weekly microarray option for patients. The concept of sustained release was initially proven in mini-pigs whereby simple intradermal administration of a nanomilled dutasteride suspension (0.12 mg/kg) was associated with an exposure period of at least 1 month. Dissolvable microarrays were successfully manufactured using a nanomilled suspension and were administered to rats at doses up to 0.32 mg/kg. In these studies, serum dutasteride was quantifiable for approximately 2 weeks after a single application. In silico modeling of the rat data using a two-compartment intradermal model was conducted and predicted that, in humans, a once-weekly dose of 2 mg, given as a microarray, could deliver cumulative and therapeutically relevant levels of dutasteride in a manner which is comparable to that observed with the current oral regimen.

Carbohydrate Intolerance and Disaccharidase Measurement - a Mini-Review.

Carbohydrate intolerance is one of several syndromes and diseases which together are known as malabsorption syndromes. These include small intestinal bacterial overgrowth (SIBO), coeliac disease, intestinal lymphangiectasia, short bowel syndrome, tropical sprue and some inherited metabolic disorders such as galactosaemia and pyruvate kinase deficiency. Specifically, the malabsorption of sugars affects morbidity for millions of sufferers across the world. Disaccharidase measurement is used in the investigation of disorders of the gastrointestinal tract. Diagnosis is by endoscopic small bowel biopsy of the duodenum or jejunum with subsequent biochemical and histopathological analysis. The diagnosis of bowel disorders presents several challenges with numerous overlapping presentations and symptoms such as bloating, diarrhoea, constipation, flatulence, borborygmus, weight loss and severe discomfort.

Value of routine echocardiography in the management of stroke.

BACKGROUND: Transthoracic echocardiography is routinely performed in patients with stroke or transient ischemic attack (TIA) to help plan secondary stroke management, but recent data evaluating its usefulness in this context are lacking. We sought to evaluate the value of echocardiography for identifying clinically actionable findings for secondary stroke prevention. METHODS: We conducted a multicentre cohort study of patients admitted to hospital with stroke or TIA between 2010 and 2015 at 2 academic hospitals in Toronto, Ontario, Canada. Clinically actionable echocardiographic findings for secondary stroke prevention included cardiac thrombus, patent foramen ovale, atrial myxoma or valvular vegetation. We identified patient characteristics associated with clinically actionable findings using logistic regression. RESULTS: Of the 1862 patients with stroke or TIA we identified, 1272 (68%) had at least 1 echocardiogram. Nearly all echocardiograms were transthoracic; 1097 (86%) were normal, 1 (0.08%) had an atrial myxoma, 2 (0.2%) had a valvular vegetation, 11 (0.9%) had a cardiac thrombus and 66 (5.2%) had a PFO. Patent foramen ovale was less likely among patients older than 60 years (adjusted odds ratio [OR] 0.34, 95% confidence interval [CI] 0.20-0.57), with prior stroke or TIA (adjusted OR 0.31, 95% CI 0.09-0.76) or with dyslipidemia (adjusted OR 0.39, 95% CI 0.15-0.84). Among the 130 patients with cryptogenic stroke who had an echocardiogram (n = 110), a PFO was detected in 19 (17%) on transthoracic echocardiogram. INTERPRETATION: Most patients with stroke or TIA had a normal echocardiogram, with few having clinically actionable findings for secondary stroke prevention. Clinically actionable findings, specifically PFO, were more common in patients with cryptogenic stroke.

Challenges and Opportunities for Patient Centric Drug Product Design: Industry Perspectives.

For an industry dedicated to preventing and treating disease, the concept of patient centric drug product design is remarkably new, yet it is beginning to transform medicinal development. The paternalistic paradigm of delivering efficacious and safe medicinal products, with inconsistent emphasis on patient centric considerations, is no longer sufficient. Patient expectations have evolved, and treatment use must complement patients' daily lives. While designing medicines to facilitate patients' use is now expected, the patient diversity across sub-populations and markets as well as industrial factors such as physicochemical properties, supply chain and shelf life aspects may preclude the development of a single, universal patient centric solution that meets all the needs of those with a particular disease. The objective of this publication is to highlight the complexities of implementing patient centric drug product design through a hypothetical HIV case study using the existing development and business processes to raise awareness and to suggest opportunities for collaboration.

Receptor tyrosine kinase inhibitors cause dysfunction in adult rat cardiac fibroblasts in vitro.

The anti-cancer receptor tyrosine kinase inhibitors include known cardiotoxins: a component of this toxicity may be mediated by effects on cardiac fibroblasts (CFs). We hypothesised that imatinib mesylate (imatinib) and sunitinib malate (sunitinib) cause significant dysfunction in adult CFs. Following in vitro treatments with imatinib or sunitinib, adult rat CF viability was assessed by fluorescein diacetate assay, proliferation measured by bromodeoxyuridine nuclear incorporation and changes to the expression of CF secretome components determined by real time quantitative RT-PCR. Imatinib and sunitinib significantly reduced cell viability over 48 h, with EC50 values of 11.0 µM (imatinib) and 4.5 µM (sunitinib) respectively. Imatinib reduced CF proliferation from 35.5 ±â€¯3.2% in control to 23.0 ±â€¯5.5% (3 µM; p < 0.001) and to 9.4 ±â€¯2.5% (10 µM; p < 0.001), whereas sunitinib reduced proliferation to 22.9 ±â€¯3.1% (1 µM; p < 0.001) and to 15 ±â€¯1.0% (3 µM; p < 0.001). Further, 10 µM imatinib increased mRNA expression of TGFB1 7-fold, (p < 0.01), IL6 6-fold (p < 0.01), and IL1B 7-fold (p < 0.05) and reduced PDGFD 15-fold (p < 0.01); whereas sunitinib specifically reduced IL1B mRNA expression 17-fold (p < 0.01). Overall, these findings show tyrosine kinase inhibitors cause significant dysfunction in CFs. These data point to an important role for the PDGF pathway in governing CF functions, including survival and proliferation.

Prognostic and biological significance of the proangiogenic factor EGFL7 in acute myeloid leukemia.

Epithelial growth factor-like 7 (EGFL7) is a protein that is secreted by endothelial cells and plays an important role in angiogenesis. Although EGFL7 is aberrantly overexpressed in solid tumors, its role in leukemia has not been evaluated. Here, we report that levels of both EGFL7 mRNA and EGFL7 protein are increased in blasts of patients with acute myeloid leukemia (AML) compared with normal bone marrow cells. High EGFL7 mRNA expression associates with lower complete remission rates, and shorter event-free and overall survival in older (age ≥60 y) and younger (age <60 y) patients with cytogenetically normal AML. We further show that AML blasts secrete EGFL7 protein and that higher levels of EGFL7 protein are found in the sera from AML patients than in sera from healthy controls. Treatment of patient AML blasts with recombinant EGFL7 in vitro leads to increases in leukemic blast cell growth and levels of phosphorylated AKT. EGFL7 blockade with an anti-EGFL7 antibody reduced the growth potential and viability of AML cells. Our findings demonstrate that increased EGFL7 expression and secretion is an autocrine mechanism supporting growth of leukemic blasts in patients with AML.

Understanding and Managing Immune-Related Adverse Events Associated With Immune Checkpoint Inhibitors in Patients With Advanced Melanoma.

The immune checkpoint inhibitors ipilimumab, nivolumab, and pembrolizumab represent a substantial improvement in treating advanced melanoma but are associated with adverse events (AEs) likely related to general immunologic enhancement. To ensure that patients receive optimal benefit from these agents, prompt assessment and treatment of AEs are essential. We review the efficacy and safety profiles of these immune checkpoint inhibitors and describe guidelines for managing immune-related AEs. We also present case studies describing the management of toxicities in patients receiving immune checkpoint inhibitor therapy. These cases illustrate the importance of collecting a detailed medical history when administering immunotherapy, as this information is necessary to establish baseline, inform monitoring, and determine the etiology of symptoms. Advanced practice nurses and physician assistants are uniquely positioned to educate patients on the early recognition of AEs and have an important role in establishing appropriate monitoring and open dialogue among services.

Base-Modified Nucleosides as Chemotherapeutic Agents: Past and Future.

Nucleoside and nucleobase antimetabolites have substantially impacted treatment of cancer and infections. Their close resemblance to natural analogs gives them the power to interfere with a variety of intracellular targets, which on one hand gives them high potency, but on the other hand incurs severe side effects, especially of the chemotherapeutics used against malignancies. Therefore, the development of novel nucleoside analogs with widened therapeutic windows represents an attractive target to synthetic organic and medicinal chemists. This review discusses the current antimetabolite drugs: 5- fluorouracil, 6-mercaptopurine, 6-thioguanine, Cladribine, Vidaza, Decitabine, Emtricitabine, Abacavir, Sorivudine, Clofarabine, Fludarabine, and Nelarabine; gives insight into the nucleoside drug candidates that are being developed; and outlines the approaches to nucleobase modifications that may help discover novel bioactive nucleoside analogs with the mechanism of action focused on termination of DNA synthesis, which is expected to diminish the off-target toxicity in non-proliferating human cells.