Equine neuroaxonal dystrophy/degenerative myeloencephalopathy in Gypsy Vanner horses

BACKGROUND

Equine neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM) is a neurodegenerative disease that primarily affects young, genetically predisposed horses that are deficient in vitamin E. Equine NAD/EDM has not previously been documented in Gypsy Vanner horses (GVs).

OBJECTIVES

To evaluate: (1) the clinical phenotype, blood vitamin E concentrations before and after supplementation and pedigree in a cohort of GV horses with a high prevalence of neurologic disease suspicious for eNAD/EDM and (2) to confirm eNAD/EDM in GVs through postmortem evaluation.

ANIMALS

Twenty-six GVs from 1 farm in California and 2 cases from the Midwestern U.S.

METHODS

Prospective observational study on Californian horses; all 26 GVs underwent neurologic examination. Pre-supplementation blood vitamin E concentration was assessed in 17- GVs. Twenty-three were supplemented orally with 10 IU/kg of liquid RRR-alpha-tocopherol once daily for 28 days. Vitamin E concentration was measured in 23 GVs after supplementation, of which 15 (65%) had pre-supplementation measurements. Two clinically affected GVs from California and the 2 Midwestern cases had necropsy confirmation of eNAD/EDM.

RESULTS

Pre-supplementation blood vitamin E concentration was ≤2.0 μg/mL in 16/17 (94%) of GVs from California. Post-supplementation concentration varied, with a median of 3.39 μg/mL (range, 1.23-13.87 μg/mL), but only 12/23 (52%) were normal (≥3.0 μg/mL). Normalization of vitamin E was significantly associated with increasing age (P = .02). Euthanized horses (n = 4) had eNAD/EDM confirmed at necropsy.

CONCLUSIONS AND CLINICAL IMPORTANCE

GVs could have a genetic predisposition to eNAD/EDM. Vitamin E supplementation should be considered and monitored in young GVs.

Clinicopathological and pedigree investigation of a novel spinocerebellar neurological disease in juvenile Quarter Horses in North America

BACKGROUND

In 2020, a novel neurologic disease was observed in juvenile Quarter Horses (QHs) in North America. It was unknown if this was an aberrant manifestation of another previously described neurological disorder in foals, such as equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM).

HYPOTHESIS/OBJECTIVES

To describe the clinical findings, outcomes, and postmortem changes with Equine Juvenile Spinocerebellar Ataxia (EJSCA), differentiate the disease from other similar neurological disorders, and determine a mode of inheritance.

ANIMALS

Twelve neurologically affected QH foals and the dams.

METHODS

Genomic DNA was isolated and pedigrees were manually constructed.

RESULTS

All foals (n = 12/12) had a history of acute onset of neurological deficits with no history of trauma. Neurological deficits were characterized by asymmetrical spinal ataxia, with pelvic limbs more severely affected than thoracic limbs. Clinicopathological abnormalities included high serum activity of gamma-glutamyl transferase and hyperglycemia. All foals became recumbent (median, 3 days: [0-18 days]), which necessitated humane euthanasia (n = 11/12, 92%; the remaining case was found dead). Histological evaluation at postmortem revealed dilated myelin sheaths and digestion chambers within the spinal cord, most prominently in the dorsal spinocerebellar tracts. Pedigree analysis revealed a likely autosomal recessive mode of inheritance.

CONCLUSIONS AND CLINICAL IMPORTANCE

EJSCA is a uniformly fatal, rapidly progressive, likely autosomal recessive neurological disease of QHs <1 month of age in North America that is etiologically distinct from other clinically similar neurological disorders. Once the causative variant for EJSCA is validated, carriers can be identified through genetic testing to inform breeding decisions.

Primary and secondary leptomeningeal gliomatosis in dogs

Leptomeningeal gliomatosis (LG) is characterized by extensive dissemination of neoplastic glial cells in the subarachnoid space either without an intraparenchymal glioma (primary LG or PLG) or secondary to an intraparenchymal glioma (secondary LG or SLG). Given the low frequency of LG in human and veterinary medicine, specific diagnostic criteria are lacking. Here, we describe 14 cases of canine LG that were retrospectively identified from 6 academic institutions. The mean age of affected dogs was 7.3 years and over 90% of patients were brachycephalic. Clinical signs were variable and progressive. Relevant magnetic resonance image findings in 7/14 dogs included meningeal enhancement of affected areas and/or intraparenchymal masses. All affected dogs were euthanized because of the poor prognosis. Gross changes were reported in 12/14 cases and consisted mainly of gelatinous leptomeningeal thickening in the brain (6/12 cases) or spinal cord (2/12 cases) and 1 or multiple, gelatinous, gray to red intraparenchymal masses in the brain (6/12 cases). Histologically, all leptomeningeal neoplasms and intraparenchymal gliomas were morphologically consistent with oligodendrogliomas. Widespread nuclear immunolabeling for OLIG2 was observed in all neoplasms. The absence of an intraparenchymal glioma was consistent with PLG in 3 cases. The remaining 11 cases were diagnosed as SLG.

High-Grade, Stage 2 Mast Cell Tumors: Outcome in Dogs With Local and Systemic Therapy

Canine mast cell tumors (MCTs) have highly variable clinical behavior, and predicting outcomes in individual dogs remains challenging. Many studies combine dogs with varying tumor grades, clinical stage, or treatments, confounding those results. The purpose of this retrospective study was to determine outcome and prognostic factors in a specific subset of dogs with high-grade, stage 2, cutaneous MCTs treated with adequate local control via surgery with or without radiation therapy and adjuvant cytotoxic chemotherapy. Seventeen dogs met the inclusion criteria, and the median survival time was 259 days. Development of local recurrence, tumor location, and presence of ulceration were all associated with shorter survival times. Tumor size, mitotic count, chemotherapy protocol, lymph node classification, and radiation therapy were not significantly associated with outcome. In this study, a specific population of dogs characterized by high-grade MCTs with local lymph node metastasis who received aggressive local and systemic therapy had a median survival of about 8.5 mo. Dogs with ulcerated tumors, recurrent tumors, or tumors located on the head had a worse outcome despite aggressive therapy. These results may serve as a basis of comparison for future research exploring alternative treatment combinations in this specific population of dogs.

Intra- and Intertumoral Microglia/Macrophage Infiltration and Their Associated Molecular Signature Is Highly Variable in Canine Oligodendroglioma: A Preliminary Evaluation

The goal of this study was to define the glioma-associated microglia/macrophage (GAM) response and associated molecular landscape in canine oligodendrogliomas. Here, we quantified the intratumoral GAM density of low- and high-grade oligodendrogliomas compared to that of a normal brain, as well as the intratumoral concentration of several known GAM-derived pro-tumorigenic molecules in high-grade oligodendrogliomas compared to that in a normal brain. Our analysis demonstrated marked intra- and intertumoral heterogeneity of GAM infiltration. Correspondingly, we observed significant variability in the intratumoral concentrations of several GAM-associated molecules, unlike what we previously observed in high-grade astrocytomas. However, high-grade oligodendroglioma tumor homogenates (n = 6) exhibited an increase in the pro-tumorigenic molecules hepatocyte growth factor receptor (HGFR) and vascular endothelial growth factor (VEGF), as we observed in high-grade astrocytomas. Moreover, neoplastic oligodendrocytes displayed robust expression of GAL-3, a chimeric galectin implicated in driving immunosuppression in human glioblastoma. While this work identifies shared putative therapeutic targets across canine glioma subtypes (HGFR, GAL-3), it highlights several key differences in the immune landscape. Therefore, a continued effort to develop a comprehensive understanding of the immune microenvironment within each subtype is necessary to inform therapeutic strategies going forward.

Oculosystemic pneumocystosis in 2 sibling Chihuahuas

Sibling female and male Chihuahuas were evaluated for a 9-month history of tachypnea that failed to respond to fenbendazole, doxycycline, amoxicillin-clavulanate, and prednisone. Physical examination identified tachypnea, hyperpnea, and harsh bronchovesicular lung sounds. Fundic examination disclosed diffuse chorioretinitis, manifested as multifocal chorioretinal granulomas in the female dog and occasional chorioretinal scars in the male dog. Thoracic radiographs indicated moderate to severe interstitial to broncho-interstitial infiltrates in both dogs. Serum and urine antigen and antibody testing in the female dog failed to identify infectious agents, but cytologic assessment of hepatic lymph node, liver, and splenic aspirates identified Pneumocystis trophozoites. Infection was confirmed in both dogs by 28S rRNA PCR sequencing from multiple tissue samples. The female dog responded well to trimethoprim-sulfamethoxazole, but the male dog was euthanized because of liver failure, presumably related to antimicrobial treatment.

Fatal balamuthosis in a Siberian tiger and a literature review of detection options for free-living amoebic infections in animals

Free-living amoebae are rare causes of morbidity and mortality in humans and animals around the globe. Because the route of exposure and clinical progression of disease caused by different species of amoebae may vary in people and animals, determining the species of amoeba present is important. We describe here a fatal infection by the free-living amoeba Balamuthia mandrillaris in a Siberian tiger (Panthera tigris altaica). The 17-y-old patient had a rapid clinical decline after a peracute onset of severe lethargy, dull mentation, and anorexia. Autopsy did not identify a cause of death. Histology revealed inflammation associated with amoebic trophozoites in the brain, lungs, and iris of one eye. These amoebae were confirmed to be B. mandrillaris based on a PCR assay and sequencing. Although there are subtle morphologic differences between cyst stages of Acanthamoeba spp., B. mandrillaris, and Naegleria fowleri when present and identified on routine staining, other modalities, including PCR, immunofluorescence, electron microscopy, and immunohistochemistry, are typically utilized to confirm the pathogen involved in these cases. We review the reports of balamuthosis in animals.

Lung and lymph node explants to study the interaction between host cells and canine distemper virus

Canine distemper virus (CDV, family Paramyxoviridae) is a widely known fatal disease in unvaccinated dogs and wild carnivores. The virus enters via the respiratory tract and rapidly spreads to the lymphoid organs. To investigate viral entry into these tissues, a dog tissue explant model was developed for lung and lymph nodes. Canine lung explants were cultured with CDV for three days. During this time CDV antigens were visible on alveolar cells, which were CD163-positive and SLAM-positive (signaling lymphocytic activation molecule), demonstrating that they were macrophages. The lymph node explants were maintained for five days. During this time the viral replication increased progressively by each day post infection and syncytia were observed by day three, post exposure. The microscopic distribution of CDV-positive cells in the lymph nodes, including the syncytia, and co-expression of CD163 and SLAM, demonstrated that they were macrophages. These findings suggest that alveolar macrophages are the first cells in the lung to become infected during CDV infection, and lymph node explants showed similar replication rates and virus-cell interactions as seen in experimental live animals. This demonstrates the utility of canine respiratory and lymphoid explant model to evaluate cell entry and viral replication of CDV and other morbilliviruses in dogs or other susceptible carnivores.

Case series: Pleural effusion caused by urinary ultrafiltrate in two cats without evidence of urinary obstruction, trauma, or simultaneous perinephric pseudocysts

Objectives

To describe the diagnostic techniques, surgical treatments, and outcomes of two cats with recurrent pleural transudate caused by urinary ultrafiltrate.

Animals

Two cats without evidence of trauma, urinary tract obstruction, or concurrent perinephric pseudocysts that were evaluated and treated for recurrent pleural transudate caused by urinary ultrafiltrate.

Study design

Short case series.

Methods

Multiphase contrast CT scan revealed leakage of contrast media from the kidneys bilaterally into the retroperitoneal spaces in both cats. Renal scintigraphy performed in one cat revealed progressive accumulation of 99mTc diethylenetriamine penta-acetic acid (Tc-DTPA) in the pleural space. Exploratory laparotomy localized the leakage of fluid to renal capsular defects bilaterally in both cats. The retroperitoneum was incised bilaterally to promote fluid drainage into the peritoneum, and nephropexies were performed.

Results

One cat had long-term survival with recurrent, though decreasing volumes of, pleural effusion. The second cat was euthanized 16 days postoperatively for progressive renal disease.

Conclusion

The diagnosis of spontaneous urinary ultrafiltrate accumulation in the pleural space of cats without evidence of trauma, urinary tract obstruction, or concurrent perinephric pseudocysts has not previously been reported. The surgical correction described reduced but did not completely eliminate the rate of pleural effusion accumulation.

Case Report: MRI, Clinical, and Pathological Correlates of Bromethalin Toxicosis in Three Dogs

Bromethalin toxicosis is an increasingly common clinical presentation in dogs that may be fatal depending on the extent of intoxication. Antemortem diagnosis of bromethalin toxicosis was achieved in three dogs by demonstration of the active metabolite desmethylbromethalin in fat or serum. Magnetic resonance imaging (MRI) findings were consistent with a diffuse leukoencephalopathy with restricted diffusion and prominent involvement of the corticospinal motor tracts on T2-weighted and diffusion-weighted sequences. Imaging findings were confirmed in one non-surviving dog at necropsy. Resolution of MRI abnormalities was demonstrated in one surviving dog that was consistent with the associated resolution of clinical signs. Initial findings in these dogs support further investigation of specific MRI patterns in cases of leukoencephalopathy to aid differential diagnosis. While antemortem detection of bromethalin and its metabolites confirms exposure, quantitation may be informative as a prognostic biomarker.

Encephalopathy caused by Talisia esculenta intoxication in pregnant ewes and their newborn lambs

An outbreak of acute encephalopathy occurred in pregnant ewes and their newborn lambs associated with consumption of Talisia esculenta fruits and bark. Clinical signs in 5 adult pregnant ewes included drooling, bloat, tachypnea, depression, ataxia, body shaking, difficulty in rising, and recumbency. Three neonatal lambs born to some of those ewes had similar clinical signs. No significant gross abnormalities were observed on autopsy. Histologically, neuronal necrosis, axonal and dendritic swelling, and loss of Purkinje neurons were observed in the cerebellum. The observation of similar neurologic clinical signs and lesions in pregnant ewes and their neonatal lambs suggests that the toxic principle of T. esculenta crosses the placenta and reaches the fetus.

Evaluation of accuracy for 18 F-FDG positron emission tomography and computed tomography for detection of lymph node metastasis in canine oral malignant melanoma

Tumour stage has been demonstrated to have prognostic significance in canine oral malignant melanoma (OMM). Various evaluation techniques of positron emission tomography/computed tomography (PET/CT) have been reported for staging of head-and-neck tumours in people, but canine-specific data are limited, and reports for CT accuracy have been variable. In this prospective study, the head/neck of client-owned dogs with cytologically or histologically diagnosed OMM were imaged with 18 Fluorine-fluorodeoxyglucose (18 F-FDG) PET/ CT. Bilateral mandibular lymphadenectomy was performed for histopathologic assessment. Two evaluation techniques for CT and PET were applied by four independent observers. CT evaluation utilized both a standardized grading scheme and a subjective clinical interpretation. PET evaluation was first performed solely on 18 F-FDG-uptake in lymph nodes compared to background on a truncated scan excluding the oral cavity. Subsequently, the entire head/neck scan and standardized uptake value (SUV) measurements were available. Receiver operating characteristic analysis was performed with histopathology as gold standard. Twelve dogs completed the study and metastatic OMM was identified in six mandibular lymph nodes from five dogs. Of the CT-interpretation techniques, use of clinical grading performed best (sensitivity = 83% and specificity = 94%). Both PET techniques resulted in 100% sensitivity, but primary tumour site evaluation and use of SUV increased specificity from 78% to 94%. The SUVmax cut-point, 3.3, led to 100% sensitivity and 83% specificity. In this population of dogs, PET appeared to be highly sensitive but at risk of being less specific without use of appropriate parameters and thresholds.

A comparative analysis of two unrelated outbreaks in Latvia and Australia of acquired idiopathic megaesophagus in dogs fed two brands of commercial dry dog foods: 398 cases (2014-2018)

CASE DESCRIPTION

In Latvia in 2014, acquired idiopathic megaesophagus (AIME) was observed in increased numbers of dogs that consumed varieties of 1 brand of dog food. Within 2 years, 253 dogs were affected. In Australia in November 2017, 6 working dogs that consumed 1 diet of another brand of dog food developed AIME. In total, 145 Australian dogs were affected.

CLINICAL FINDINGS

AIME was diagnosed predominantly in large-breed male dogs (> 25 kg [55 lb]). Regurgitation, weight loss, and occasionally signs consistent with aspiration pneumonia (coughing, dyspnea, or fever) were noted. Most Latvian dogs had mild to severe peripheral polyneuropathies as evidenced by laryngeal paralysis, dysphonia, weakness, and histopathologic findings consistent with distal axonopathy. In Australian dogs, peripheral polyneuropathies were not identified, and histopathologic findings suggested that the innervation of the esophagus and pharynx was disrupted locally, although limited samples were available.

TREATMENT AND OUTCOME

Investigations in both countries included clinical, epidemiological, neuropathologic, and case-control studies. Strong associations between the dog foods and the presence of AIME were confirmed; however, toxicological analyses did not identify a root cause. In Latvia, the implicated dietary ingredients and formulations were unknown, whereas in Australia, extensive investigations were conducted into the food, its ingredients, the supply chain, and the manufacturing facilities, but a cause was not identified.

CLINICAL RELEVANCE

A panel of international multidisciplinary experts concluded that the cause of AIME in both outbreaks was likely multifactorial, with the possibility of individualized sensitivities. Without a sentinel group, the outbreak in Australia may not have been recognized for months to years, as happened in Latvia. A better surveillance system for early identification of pet illnesses, including those associated with pet foods, is needed.

Postmortem diagnoses of spinal ataxia in 316 horses in California

OBJECTIVE

To determine period prevalences of postmortem diagnoses for spinal cord or vertebral column lesions as underlying causes of ataxia (spinal ataxia) in horses.

ANIMALS

2,861 client-owned horses (316 with ataxia [ataxic group] and 2,545 without ataxia [control group]).

PROCEDURES

The medical records database of the University of California-Davis Veterinary Medical Teaching Hospital was searched to identify horses necropsied between January 1, 2005, and December 31, 2017. Results were compared between the ataxic and control groups and between various groups of horses in the ataxic group. Period prevalences were determined for the most common causes of ataxia.

RESULTS

2,861 horses underwent full necropsy, and the period prevalences for the most common definitive diagnoses for ataxia were 2.7% (77/2,861) for cervical vertebral compressive myelopathy (CVCM), 1.3% (38/2,861) for equine neuroaxonal dystrophy or equine degenerative myeloencephalopathy (eNAD-EDM), and 0.9% (25/2,861) for trauma; the period prevalence of ataxia of unknown origin was 2.0% (56/2,861). Horses in the ataxic group (vs the control group) were more likely to have been warmblood horses (OR, 2.70) and less likely to have been Arabian horses (OR, 0.53). In the ataxic group, horses < 5 (vs ≥ 5) years of age had greater odds of CVCM (OR, 2.82) or eNAD-EDM (OR, 6.17) versus trauma or ataxia of unknown origin. Horses in the ataxic group with CVCM were more likely Thoroughbreds (OR, 2.54), whereas horses with eNAD-EDM were more likely American Quarter Horses (OR, 2.95) and less likely Thoroughbreds (OR, 0.11).

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that breed distributions differed for horses with CVCM versus eNAD-EDM; therefore, breed should be considered in the clinical evaluation of spinal ataxia in horses.

Comparative Pathology of the Peripheral Nervous System

The peripheral nervous system (PNS) relays messages between the central nervous system (brain and spinal cord) and the body. Despite this critical role and widespread distribution, the PNS is often overlooked when investigating disease in diagnostic and experimental pathology. This review highlights key features of neuroanatomy and physiology of the somatic and autonomic PNS, and appropriate PNS sampling and processing techniques. The review considers major classes of PNS lesions including neuronopathy, axonopathy, and myelinopathy, and major categories of PNS disease including toxic, metabolic, and paraneoplastic neuropathies; infectious and inflammatory diseases; and neoplasms. This review describes a broad range of common PNS lesions and their diagnostic criteria and provides many useful references for pathologists who perform PNS evaluations as a regular or occasional task in their comparative pathology practice.

A Missense Variant in ALDH5A1 Associated with Canine Succinic Semialdehyde Dehydrogenase Deficiency (SSADHD) in the Saluki Dog

Dogs provide highly valuable models of human disease due to the similarity in phenotype presentation and the ease of genetic analysis. Seven Saluki puppies were investigated for neurological abnormalities including seizures and altered behavior. Magnetic resonance imaging showed a diffuse, marked reduction in cerebral cortical thickness, and symmetrical T2 hyperintensity in specific brain regions. Cerebral cortical atrophy with vacuolation (status spongiosus) was noted on necropsy. Genome-wide association study of 7 affected and 28 normal Salukis revealed a genome-wide significantly associated region on CFA 35. Whole-genome sequencing of three confirmed cases from three different litters revealed a homozygous missense variant within the aldehyde dehydrogenase 5 family member A1 (ALDH5A1) gene (XM_014110599.2: c.866G>A; XP_013966074.2: p.(Gly288Asp). ALDH5A1 encodes a succinic semialdehyde dehydrogenase (SSADH) enzyme critical in the gamma-aminobutyric acid neurotransmitter (GABA) metabolic pathway. Metabolic screening of affected dogs showed markedly elevated gamma-hydroxybutyric acid in serum, cerebrospinal fluid (CSF) and brain, and elevated succinate semialdehyde in urine, CSF and brain. SSADH activity in the brain of affected dogs was low. Affected Saluki dogs had striking similarities to SSADH deficiency in humans although hydroxybutyric aciduria was absent in affected dogs. ALDH5A1-related SSADH deficiency in Salukis provides a unique translational large animal model for the development of novel therapeutic strategies.

Abstract 1917: The HDAC inhibitor panobinostat elicits preferential cytotoxic and antiproliferative effects in IDH mutant glioblastoma

Glioblastoma (GBM) is an incurable form of brain cancer with a median survival of ~15 months. Identification of a CpG Island Methylator Phenotype (CIMP) subtype of GBM (G-CIMP) represents a significant clinical discovery as these patients have an enhanced survival, with a median survival of 3 years. G-CIMP is characterized by a mutation in isocitrate dehydrogenase 1 or 2 (IDH1/2) which results in production of the oncometabolite 2-hydroxglutarate, an inhibitor of α-ketoglutarate-dependent DNA demethylases. This mutation occurs early in gliomagenesis and further results in aberrant DNA methylation and widespread transcriptional repression. Histone deacetylase (HDAC) enzymes are localized to methylated chromatin via methyl-binding domain (MBD) proteins, so we hypothesized that IDH mutant GBM exhibits enhanced reliance on HDAC activity, which is functionally significant to their cell proliferation and survival. Using a panel of 6 patient-derived cell lines grown in defined growth media, we show that G-CIMP is significantly more sensitive in vitro to the clinically approved pan histone deacetylase (HDAC) inhibitor panobinostat, with IDH mutant GBM cells exhibiting ~4 and ~10 fold lower IC/EC50 values in flow cytometric cell viability and apoptosis assays compared to IDH wild type (WT) GBM cells, respectively. For IDH mutant GBM, the average IC50 value was 13.5 nM for cell viability assays and the average EC50 value was 4.8 nM for apoptosis assays. Induction of cleaved caspase 3, a marker of apoptosis, was observed only in IDH mutant GBM cells when exposed to 10 nM panobinostat over 5 days. Analysis of proliferation via BrdU incorporation assays show that treatment with 10 nM panobinastat for 48 hours results in a 90% reduction in proliferation of IDH mutant GBM compared to only 25% reduction in IDH WT GBM cells. Molecular analysis via western blot shows that various acetylated chromatin marks, i.e. H3K14/18/27Ac, are preferentially upregulated in our IDH mutant GBM cell lines when exposed to 10 nM panobinostat for 48 hours. This was also supported by ELISA data showing that IDH mutant GBM cells have ~2 fold increase in histone H3 acetylation compared to IDH WT cells in response to 10 nM and 50 nM panobinostat. These data led us to perform a HDAC activity assay with nuclear extracts from our IDH WT and mutant GBM cells, but this assay showed no significant difference in basal HDAC activity. Overall, our results support a hypothesis where IDH mutant GBMs are more sensitive to panobinostat via preferential uptake of the drug. These data ultimately suggest that G-CIMP tumor cells display a profound sensitivity to the cytotoxic and antiproliferative effects mediated by exposure to the HDAC inhibitor panobinostat. These studies provide a strong foundation for future preclinical work evaluating the use of HDAC inhibitors as a personalized cancer therapy to treat G-CIMP.

Citation Format: Thomas K. Sears, Kevin D. Woolard. The HDAC inhibitor panobinostat elicits preferential cytotoxic and antiproliferative effects in IDH mutant glioblastoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1917.

Diagnosis and clinical outcome following surgical resection of an intracranial grade III anaplastic gemistocytic astrocytoma in a cat

CASE SUMMARY

A 10-year-old Maine Coon cat was presented for acute onset seizures and cerebrothalamic signs. An intracranial mass, suspected to be a meningioma, was diagnosed on MRI and surgically excised. Histopathology appeared consistent with an atypical meningioma. However, following rapid regrowth of the neoplasm, the patient was humanely euthanized 3 months later. On post-mortem histopathology, the neoplasm was diagnosed as a grade III anaplastic gemistocytic astrocytoma.

RELEVANCE AND NOVEL INFORMATION

Gemistocytic astrocytomas are rare brain tumors in the feline patient. This case represents the first report of a feline grade III anaplastic gemistocytic astrocytoma in the cerebrum of a cat with surgical excision and recurrence. The challenging nature of ante-mortem diagnosis and the guarded prognosis, despite surgical intervention, are presented in this report.

Whole genome sequencing for mutation discovery in a single case of lysosomal storage disease (MPS type 1) in the dog

Mucopolysaccharidosis (MPS) is a metabolic storage disorder caused by the deficiency of any lysosomal enzyme required for the breakdown of glycosaminoglycans. A 15-month-old Boston Terrier presented with clinical signs consistent with lysosomal storage disease including corneal opacities, multifocal central nervous system disease and progressively worsening clinical course. Diagnosis was confirmed at necropsy based on histopathologic evaluation of multiple organs demonstrating accumulation of mucopolysaccharides. Whole genome sequencing was used to uncover a frame-shift insertion affecting the alpha-L-iduronidase (IDUA) gene (c.19_20insCGGCCCCC), a mutation confirmed in another Boston Terrier presented 2 years later with a similar clinical picture. Both dogs were homozygous for the IDUA mutation and shared coat colors not recognized as normal for the breed by the American Kennel Club. In contrast, the mutation was not detected in 120 unrelated Boston Terriers as well as 202 dogs from other breeds. Recent inbreeding to select for recessive and unusual coat colors may have concentrated this relatively rare allele in the breed. The identification of the variant enables ante-mortem diagnosis of similar cases and selective breeding to avoid the spread of this disease in the breed. Boston Terriers carrying this variant represent a promising model for MPS I with neurological abnormalities in humans.

Comparative Molecular Life History of Spontaneous Canine and Human Gliomas

Sporadic gliomas in companion dogs provide a window on the interaction between tumorigenic mechanisms and host environment. We compared the molecular profiles of canine gliomas with those of human pediatric and adult gliomas to characterize evolutionarily conserved mammalian mutational processes in gliomagenesis. Employing whole-genome, exome, transcriptome, and methylation sequencing of 83 canine gliomas, we found alterations shared between canine and human gliomas such as the receptor tyrosine kinases, TP53 and cell-cycle pathways, and IDH1 R132. Canine gliomas showed high similarity with human pediatric gliomas per robust aneuploidy, mutational rates, relative timing of mutations, and DNA-methylation patterns. Our cross-species comparative genomic analysis provides unique insights into glioma etiology and the chronology of glioma-causing somatic alterations.

Metastatic immune infiltrates correlate with those of the primary tumour in canine osteosarcoma

Our lack of understanding of the immune microenvironment in canine osteosarcoma (cOSA) has limited the identification of potential immunotherapeutic targets. In particular, our ability to utilize readily available tissue from a dog's primary tumour to predict the type and extent of immune response in their pulmonary metastatic lesions is unknown. We, therefore, collected 21 matched pairs of primary tumours and pulmonary metastatic lesions from dogs with OSA and performed immunohistochemistry to quantify T-lymphocyte (CD3), FOXP3+ cell, B-lymphocyte (Pax-5), and CD204+ macrophage infiltration. We found that T-lymphocytes and FOXP3+ infiltrates in primary tumours positively correlated with that of metastatic lesions (ρ = 0.512, P = 0.038 and ρ = 0.698, P = 0.007, respectively), while a strong trend existed for CD204+ infiltrates (ρ = 0.404, P = 0.087). We also observed T- and B-lymphocytes, and CD204+ macrophages to be significantly higher in a dog's pulmonary metastasis compared to their primary tumour (P = 0.018, P = 0.018, P = 0.016, respectively), while FOXP3+ cells were only significantly higher in metastases when all primary tumour and metastasis lesions were compared without pairing (P = 0.036). Together, these findings suggest that the metastatic immune microenvironment may be influenced by that of the primary cOSA, and that primary tumour immune biomarkers could potentially be applied to predict immunotherapeutic responses in gross metastatic disease. We, therefore, provide a rationale for the treatment of cOSA pulmonary metastases with immunotherapeutics that enhance the anti-tumour activity of these immune cells, particularly in dogs with moderate to high immune cell infiltration in their primary tumours.

Clinical outcomes, ultrastructure and immunohistochemical features of canine high-grade olfactory neuroblastoma

Olfactory neuroblastoma (ONB) is a rare intranasal neoplasm in both dogs and humans. Similar clinical presentation and overlapping histologic and immunohistochemical features of ONB with other intranasal neoplasms can make diagnosis and treatment of intranasal neoplasia challenging. Furthermore, in part because of their rarity, there is a lack of reporting on therapeutic regimen for these neoplasms. In humans, initial debulking surgery is usually followed by radiation therapy. Here we report on the histologic, immunohistochemical, and ultrastructural characteristics of canine ONB and report on the clinical progression of cases treated with radiation therapy. In all nine canine ONB examined here, neoplastic cells were arranged in a lobular manner amidst a prominent neurofibrillary matrix and had features consistent with Grade III (high grade) ONB. The neoplastic cells demonstrated positive immunohistochemical staining for TuJ-1, a Class III beta-tubulin neuronal cytoskeletal protein, and variable staining for other markers, including chromogranin, synaptophysin, AE1/AE3 and MAP2. The longest surviving case was treated with a regimen similar to that used in humans, consisting of debulking surgery followed by definitive radiation therapy. Our study found that TuJ-1 is a useful marker for ONB and that radiation therapy, even in cases of advanced disease, may result in prolonged survival.

Author Correction: Cancer in wildlife: patterns of emergence

In the originally published article, the aetiology of the single case of B cell lymphoma found in the Mountain gorilla was incorrectly referred to as Gibbon lymphocryptovirus 1 in Table 1. The correct aetiology is Gbb lymphocryptovirus 1. This has now been corrected in both the html and PDF versions of the article.

Nanomedicine for Spontaneous Brain Tumors: A Companion Clinical Trial

Nanoparticles' enhanced permeation and retention (EPR) variations due to tumor heterogeneity in naturally occurring brain tumors are commonly neglected in preclinical nanomedicine studies. Recent pathological studies have shown striking similarities between brain tumors in humans and dogs, indicating that canine brain tumors may be a valuable model to evaluate nanoparticles' EPR in this context. We recruited canine clinical cases with spontaneous brain tumors to investigate nanoparticles' EPR in different brain tumor pathologies using surface-enhanced Raman spectroscopy (SERS). We used gold nanoparticles due to their surface plasmon effect that enables their sensitive and microscopic resolution detection using the SERS technique. Raman microscopy of the resected tumors showed heterogeneous EPR of nanoparticles into oligodendrogliomas and meningiomas of different grades, without any detectable traces in necrotic parts of the tumors or normal brain. Raman observations were confirmed by scanning electron microscopy (SEM) and X-ray elemental analyses, which enabled localization of individual nanoparticles embedded in tumor tissues. Our results demonstrate nanoparticles' EPR and its variations in clinically relevant, spontaneous brain tumors. Such heterogeneities should be considered alongside routine preoperative imaging and histopathological analyses in order to accelerate clinical management of brain tumors using nanomedicine approaches.

Cancer in wildlife: patterns of emergence

Cancer is ubiquitous in wildlife, affecting animals from bivalves to pachyderms and cetaceans. Reports of increasing frequency demonstrate that neoplasia is associated with substantial mortality in wildlife species. Anthropogenic activities and global weather changes are shaping new geographical limitations for many species, and alterations in living niches are associated with visible examples of genetic bottlenecks, toxin exposures, oncogenic pathogens, stress and immunosuppression, which can all contribute to cancers in wild species. Nations that devote resources to monitoring the health of wildlife often do so for human-centric reasons, including for the prediction of the potential for zoonotic disease, shared contaminants, chemicals and medications, and for observing the effect of exposure from crowding and loss of habitat. Given the increasing human footprint on land and in the sea, wildlife conservation should also become a more important motivating factor. Greater attention to the patterns of the emergence of wildlife cancer is imperative because growing numbers of species are existing at the interface between humans and the environment, making wildlife sentinels for both animal and human health. Therefore, monitoring wildlife cancers could offer interesting and novel insights into potentially unique non-age-related mechanisms of carcinogenesis across species.

Association of macrophage and lymphocyte infiltration with outcome in canine osteosarcoma

Immunotherapeutic strategies have shown promise for the treatment of canine osteosarcoma (cOSA). Very little is known about the immune microenvironment within cOSA, however, limiting our ability to identify potential immune targets and biomarkers of therapeutic response. We therefore prospectively assessed the disease-free interval (DFI) and overall survival time (ST) of 30 dogs with cOSA treated with amputation and six doses of adjuvant carboplatin. We then quantified lymphocytic (CD3+, FOXP3+) and macrophage (CD204+) infiltrates within the primary tumours of this cohort using immunohistochemistry, and evaluated their association with outcome. Overall, the median DFI and ST were 392 and 455 days, respectively. The median number of CD3+ and FOXP3+ infiltrates were 45.8 cells/mm² (4.6-607.6 cells/mm² ) and 8.5 mm² (0-163.1 cells/mm² ), respectively. The median area of CD204+ macrophages was 4.7% (1.3%-23.3%), and dogs with tumours containing greater than 4.7% CD204+ macrophages experienced a significantly longer DFI (P = 0.016). Interestingly, a significantly lower percentage of CD204+ macrophages was detected in cOSA arising from the proximal humerus compared to other appendicular bone locations (P = 0.016). Lymphocytic infiltrates did not appear to correlate with outcome in cOSA. Overall, our findings suggest that macrophages may play a role in inhibiting cOSA progression, as has been suggested in human osteosarcoma.

Abstract 202: Functional heterogeneity in glioblastoma: cell-cell communication regulates temporospatial events in tumor recurrence

Patients with glioblastoma frequently develop progressive disease following treatment. This is believed to occur because of an inherent or acquired resistance to chemo- and radiotherapy within residual tumor burden. However, how discrete tumor subpopulations coordinate tumor recurrence and progression is still poorly understood. Here, we describe the isolation of glioma stem cells (GSCs) from a patient prior to treatment (0203), and then from multiple sites in the brain following tumor recurrence. These sites include the recurrent tumor at the primary site (T3/T4), as well as disseminated tumor cells in the contralateral hemisphere (T6/T7). Whole exome sequencing identifies loss of all unique genomic signatures within the original tumor cells (0203) following treatment, suggesting eradication of the original tumor bulk. Moreover, genomic signatures of the recurrent tumor (T3/T4) clusters alongside disseminated subpopulations of tumor cells isolated from the contralateral hemisphere (T6/T7), suggesting that tumor recurrence is driven by repopulation of the original tumor location. Copy number variants (CNVs) between the original tumor (0203), the recurrent tumor (T3/T4), and distant tumor sites (T6/T7), identify a more primordial genome in distant tumor sites (T6/T7), which lack canonical CNVs found in the original tumor and in other subpopulations (deletion of PTEN or amplification of EGFR). Thus, tumor dissemination likely occurs early in disease development. We are able to model the patient's disease progression by using co-culture techniques and orthotopic xenograft studies. Our data indicates that 0203 cells actively suppress migration of disseminated tumor sub-populations (T6/T7) in vitro and in vivo, which is replicated by using cell-free conditioned media. In stark contrast, the induction of apoptosis in 0203 cells (or treating with conditioned media from apoptotic 0203 cells) rapidly recruits migration of disseminated cells (T6/T7) in a co-culture system. Co-culture of disseminated GSCs (T6/T7) with viable 0203 cells also results in suppression of pathways implicated in glioma migration, such as AKT, CXCR4, TrkA, and CLCN3; suppression that is reversed upon induction of apoptosis in 0203 cells. These data indicate that while widespread tumor dissemination occurs early in glioblastoma, a dominant subpopulation may actively suppress proliferation of separate, disseminated subpopulations. Moreover, abrogating this suppression following therapy triggers migration and proliferation of specific, distant tumor sub-populations, resulting in tumor recurrence. This suggests that glioblastoma recurrence may not be as simple as selection of radioresistant cells, rather it may result from the active recruitment of disseminated subpopulations, which migrate to the original tumor microenvironment.

Citation Format: Kevin D. Woolard, Patrick Huang, Thomas K. Sears, Matthew Settles. Functional heterogeneity in glioblastoma: cell-cell communication regulates temporospatial events in tumor recurrence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 202.

Safety and tracking of intrathecal allogeneic mesenchymal stem cell transplantation in healthy and diseased horses

Background

It is currently unknown if the intrathecal administration of a high dose of allogeneic mesenchymal stem cells (MSCs) is safe, how MSCs migrate throughout the vertebral canal after intrathecal administration, and whether MSCs are able to home to a site of injury. The aims of the study were: 1) to evaluate the safety of intrathecal injection of 100 million allogeneic adipose-derived MSCs (ASCs); 2) to assess the distribution of ASCs after atlanto-occipital (AO) and lumbosacral (LS) injection in healthy horses; and 3) to determine if ASCs homed to the site of injury in neurologically diseased horses.

Methods

Six healthy horses received 100 × 10⁶ allogeneic ASCs via AO (n = 3) or LS injection (n = 3). For two of these horses, ASCs were radiolabeled with technetium and injected AO (n = 1) or LS (n = 1). Neurological examinations were performed daily, and blood and cerebrospinal fluid (CSF) were evaluated prior to and at 30 days after injection. Scintigraphic images were obtained immediately postinjection and at 30 mins, 1 h, 5 h, and 24 h after injection. Three horses with cervical vertebral compressive myelopathy (CVCM) received 100 × 10⁶ allogeneic ASCs labeled with green fluorescent protein (GFP) via AO injection and were euthanized 1–2 weeks after injection for a full nervous system necropsy. CSF parameters were compared using a paired student’s t test.

Results

There were no significant alterations in blood, CSF, or neurological examinations at any point after either AO or LS ASC injections into healthy horses. The radioactive signal could be identified all the way to the lumbar area after AO ASC injection. After LS injection, the signal extended caudally but only a minimal radioactive signal extended further cranially. GFP-labeled ASCs were not present at the site of disease at either 1 or 2 weeks following intrathecal administration.

Conclusions

The intrathecal injection of allogeneic ASCs was safe and easy to perform in horses. The AO administration of ASCs resulted in better distribution within the entire subarachnoid space in healthy horses. ASCs could not be found after 7 or 15 days of injection at the site of injury in horses with CVCM.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0849-6) contains supplementary material, which is available to authorized users.

Allogeneic Stem Cells Alter Gene Expression and Improve Healing of Distal Limb Wounds in Horses

Distal extremity wounds are a significant clinical problem in horses and humans and may benefit from mesenchymal stem cell (MSC) therapy. This study evaluated the effects of direct wound treatment with allogeneic stem cells, in terms of gross, histologic, and transcriptional features of healing. Three full-thickness cutaneous wounds were created on each distal forelimb in six healthy horses, for a total of six wounds per horse. Umbilical cord-blood derived equine MSCs were applied to each wound 1 day after wound creation, in one of four forms: (a) normoxic- or (b) hypoxic-preconditioned cells injected into wound margins, or (c) normoxic- or (d) hypoxic-preconditioned cells embedded in an autologous fibrin gel and applied topically to the wound bed. Controls were one blank (saline) injected wound and one blank fibrin gel-treated wound per horse. Data were collected weekly for 6 weeks and included wound surface area, thermography, gene expression, and histologic scoring. Results indicated that MSC treatment by either delivery method was safe and improved histologic outcomes and wound area. Hypoxic-preconditioning did not offer an advantage. MSC treatment by injection resulted in statistically significant increases in transforming growth factor beta and cyclooxygenase-2 expression at week 1. Histologically, significantly more MSC-treated wounds were categorized as pro-healing than pro-inflammatory. Wound area was significantly affected by treatment: MSC-injected wounds were consistently smaller than gel-treated or control wounds. In conclusion, MSC therapy shows promise for distal extremity wounds in horses, particularly when applied by direct injection into the wound margin. Stem Cells Translational Medicine 2018;7:98-108.

Evaluation of P16 expression in canine appendicular osteosarcoma

BACKGROUND

Osteosarcoma (OSA) is a common malignant bone tumor of large breed dogs that occurs at predictable anatomic sites. At the time of initial diagnosis, most affected dogs have occult pulmonary metastases. Even with aggressive surgical treatment combined with chemotherapy, the majority of dogs diagnosed with OSA live less than 1 year from the time of diagnosis. The ability to identify canine OSA cases most responsive to treatment is needed. In humans, OSA is also an aggressive tumor that is histologically and molecularly similar to canine OSA. The expression of the tumor suppressor gene product P16 by human OSA tissue has been linked to a favorable response to chemotherapy.

RESULTS

We identified an antibody that binds canine P16 and developed a canine OSA tissue microarray in order to test the hypothesis that P16 expression by canine OSA tissue is predictive of clinical outcome following amputation and chemotherapy. Although statistical significance was not reached, a trend was identified between the lack of canine OSA P16 expression and a shorter disease free interval.

CONCLUSIONS

The identification of a molecular marker for canine OSA is an important goal and the results reported here justify a larger study.

Polyomavirus and Naturally Occuring Neuroglial Tumors in Raccoons (Procyon Lotor)

Polyomavirus (PyV) infections are widespread in human populations and, although generally associated with silent persistence, rarely cause severe disease. Among diseases convincingly associated with natural PyV infections of humans, there are remarkably different tissue tropisms and outcomes, including progressive multifocal leukoencephalopathy, transient or progressive nephropathy, and cancer. The variable character and unpredictable outcomes of infection attest to large gaps in our basic understanding of PyV biology. In particular, the rich history of research demonstrating the oncogenic potential of PyVs in laboratory animals begs the question of why cancer is not more often associated with infection. Raccoon polyomavirus (RacPyV), discovered in 2010, is consistently identified in neuroglial tumors in free-ranging raccoons in the western United States. Exposure to RacPyV is widespread, and RacPyV is detected in tissues of raccoons without tumors. Studying the relationship of RacPyV with its natural host is a unique opportunity to uncover cogent cellular targets and protein interactions between the virus and its host. Our hypothesis is that RacPyV, as an intact episome, alters cellular pathways within neural progenitor cells and drives oncogenesis.

BRD4 is associated with raccoon polyomavirus genome and mediates viral gene transcription and maintenance of a stem cell state in neuroglial tumour cells

Polyomavirus infection often results in persistence of the viral genome with little or no virion production. However, infection of certain cell types can result in high viral gene transcription and either cytolysis or neoplastic transformation. While infection by polyomavirus is common in humans and many animals, major questions regarding viral persistence of most polyomaviruses remain unanswered. Specifically, identification of target cells for viral infection and the mechanisms polyomaviruses employ to maintain viral genomes within cells are important not only in ascribing causality to polyomaviruses in disease, but in understanding specific mechanisms by which they cause disease. Here, we characterize the cell of origin in raccoon polyomavirus (RacPyV)-associated neuroglial brain tumours as a neural stem cell. Moreover, we identify an association between the viral genome and the host cell bromodomain protein, BRD4, which is involved in numerous cellular functions, including cell cycle progression, differentiation of stem cells, tethering of persistent DNA viruses, and regulation of viral and host-cell gene transcription. We demonstrate that inhibition of BRD4 by the small molecule inhibitors (+)-JQ1 and IBET-151 (GSK1210151A) results in reduced RacPyV genome within cells in vitro, as well as significant reduction of viral gene transcripts LT and VP1, highlighting its importance in both maintenance of the viral genome and in driving oncogenic transformation by RacPyV. This work implicates BRD4 as a central protein involved in RacPyV neuroglial tumour cell proliferation and in the maintenance of a stem cell state.

Production of a recombinant capsid protein VP1 from a newly described polyomavirus (RacPyV) for downstream use in virus characterization

Here we describe the methods for production of a recombinant viral capsid protein and subsequent use in an indirect enzyme linked immunosorbent assay (ELISA), and for use in production of a rabbit polyclonal antibody. These reagents were utilized in development and optimization of an ELISA, which established the extent of exposure of free ranging raccoons to a newly described polyomavirus (RacPyV) [1]. Production of a polyclonal antibody has allowed for further characterization of RacPyV, including immunohistochemistry and immunocytochemistry techniques, in order to answer questions about pathogenesis of this virus.

Exposure to raccoon polyomavirus (RacPyV) in free-ranging North American raccoons (Procyon lotor)

There is evidence that raccoon polyomavirus is causative for neuroglial brain tumors in the western United States. It is unknown if infection is limited to geographic locales where tumors have been reported or is widespread, like human polyomaviruses. We demonstrate raccoons in western, eastern and midwestern states have been exposed to RacPyV by detection of antibodies to capsid protein, VP1. While raccoons in eastern and midwestern states are seropositive, exposure is lower than in the western states. Additionally, across geographic areas seropositivity is higher in older as compared to younger raccoons, similar to polyomavirus exposure in humans. Serum titers are significantly higher in raccoons with tumors compared to raccoons without. Unlike polyomavirus-associated diseases in humans, we did not detect significant sequence variation between tumor and non-tumor tissue in raccoons with tumors compared to those without tumors. This warrants further investigation into co-morbid diseases or genetic susceptibility studies of the host.

Identification of a polyomavirus microRNA highly expressed in tumors

Polyomaviruses (PyVs) are associated with tumors including Merkel cell carcinoma (MCC). Several PyVs encode microRNAs (miRNAs) but to date no abundant PyV miRNAs have been reported in tumors. To better understand the function of the Merkel cell PyV (MCPyV) miRNA, we examined phylogenetically-related viruses for miRNA expression. We show that two primate PyVs and the more distantly-related raccoon PyV (RacPyV) encode miRNAs that share genomic position and partial sequence identity with MCPyV miRNAs. Unlike MCPyV miRNA in MCC, RacPyV miRNA is highly abundant in raccoon tumors. RacPyV miRNA negatively regulates reporters of early viral (T antigen) transcripts, yet robust viral miRNA expression is tolerated in tumors. We also identify raccoon miRNAs expressed in RacPyV-associated neuroglial brain tumors, including several likely oncogenic miRNAs (oncomiRs). This work describes the first PyV miRNA abundantly expressed in tumors and is consistent with a possible role for both host and viral miRNAs in RacPyV-associated tumors.

Recognition of glioma stem cells by genetically modified T cells targeting EGFRvIII and development of adoptive cell therapy for glioma

No curative treatment exists for glioblastoma, with median survival times of less than 2 years from diagnosis. As an approach to develop immune-based therapies for glioblastoma, we sought to target antigens expressed in glioma stem cells (GSCs). GSCs have multiple properties that make them significantly more representative of glioma tumors than established glioma cell lines. Epidermal growth factor receptor variant III (EGFRvIII) is the result of a novel tumor-specific gene rearrangement that produces a unique protein expressed in approximately 30% of gliomas, and is an ideal target for immunotherapy. Using PCR primers spanning the EGFRvIII-specific deletion, we found that this tumor-specific gene is expressed in three of three GCS lines. Based on the sequence information of seven EGFRvIII-specific monoclonal antibodies (mAbs), we assembled chimeric antigen receptors (CARs) and evaluated the ability of CAR-engineered T cells to recognize EGFRvIII. Three of these anti-EGFRvIII CAR-engineered T cells produced the effector cytokine, interferon-γ, and lysed antigen-expressing target cells. We concentrated development on a CAR produced from human mAb 139, which specifically recognized GSC lines and glioma cell lines expressing mutant EGFRvIII, but not wild-type EGFR and did not recognize any normal human cell tested. Using the 139-based CAR, T cells from glioblastoma patients could be genetically engineered to recognize EGFRvIII-expressing tumors and could be expanded ex vivo to large numbers, and maintained their antitumor activity. Based on these observations, a γ-retroviral vector expressing this EGFRvIII CAR was produced for clinical application.

Serum S100A6 concentration predicts peritoneal tumor burden in mice with epithelial ovarian cancer and is associated with advanced stage in patients

BACKGROUND

Ovarian cancer is the 5th leading cause of cancer related deaths in women. Five-year survival rates for early stage disease are greater than 94%, however most women are diagnosed in advanced stage with 5 year survival less than 28%. Improved means for early detection and reliable patient monitoring are needed to increase survival.

METHODOLOGY AND PRINCIPAL FINDINGS

Applying mass spectrometry-based proteomics, we sought to elucidate an unanswered biomarker research question regarding ability to determine tumor burden detectable by an ovarian cancer biomarker protein emanating directly from the tumor cells. Since aggressive serous epithelial ovarian cancers account for most mortality, a xenograft model using human SKOV-3 serous ovarian cancer cells was established to model progression to disseminated carcinomatosis. Using a method for low molecular weight protein enrichment, followed by liquid chromatography and mass spectrometry analysis, a human-specific peptide sequence of S100A6 was identified in sera from mice with advanced-stage experimental ovarian carcinoma. S100A6 expression was documented in cancer xenografts as well as from ovarian cancer patient tissues. Longitudinal study revealed that serum S100A6 concentration is directly related to tumor burden predictions from an inverse regression calibration analysis of data obtained from a detergent-supplemented antigen capture immunoassay and whole-animal bioluminescent optical imaging. The result from the animal model was confirmed in human clinical material as S100A6 was found to be significantly elevated in the sera from women with advanced stage ovarian cancer compared to those with early stage disease.

CONCLUSIONS

S100A6 is expressed in ovarian and other cancer tissues, but has not been documented previously in ovarian cancer disease sera. S100A6 is found in serum in concentrations that correlate with experimental tumor burden and with clinical disease stage. The data signify that S100A6 may prove useful in detecting and/or monitoring ovarian cancer, when used in concert with other biomarkers.

Clearance of a dermal Huffmanela sp. in a sandbar shark (Carcharhinus plumbeus) using levamisole

A wild-caught captive sandbar shark Carcharhinus plumbeus developed a contiguous network of darkly pigmented linear tracks that progressed from the snout to the ventral cervical region. Microscopic examination of a skin scraping revealed nematode eggs of the genus Huffmanela, a group of histozoic nematodes that is known to parasitize requiem sharks and marine and freshwater teleosts. The fresh eggs were darkly pigmented with bipolar plugs, contained a larva, and measured 73.3 to 86.4 by 39.0 to 47.4 microm (n = 10). Formalin-fixed and paraffin-embedded eggs were significantly smaller (Wilcoxon rank sums test, p < 0.005), measuring 70.5 to 78.9 by 33.6 to 41.3 microm (n = 13). These measurements do not correlate with previously reported species of Huffmanela. Serial treatment with levamisole (10 mg kg(-1), intramuscular [i.m.]) cleared the egg tracks within 21 d, with no recurrence or apparent complications.