Explore the vast range of titles available.

Background Gallbladder mucocele (GBM) is a common disease in the canine gallbladder. Although the pathogenesis of GBM remains unclear, we recently reported that the excessive accumulation of mucin in the gallbladder is not a result of overproduction by gallbladder epithelial cells (GBECs). Hypothesis/Objectives Changes in the function of GBECs other than the production of mucin are associated with the pathogenesis of GBM. We performed an RNA sequencing (RNA‐seq) analysis to comprehensively search for abnormalities in gene expression profiles of GBECs in dogs with GBM. Animals Fifteen dogs with GBM and 8 dogs euthanized for reasons other than gallbladder disease were included. Methods The GBECs were isolated from gallbladder tissues to extract RNA. The RNA‐seq analysis was performed using the samples from 3 GBM cases and 3 dogs with normal gallbladders, and the gene expression profiles were compared between the 2 groups. Differences in mRNA expression levels of the extracted differentially expressed genes (DEGs) were validated by quantitative reverse transcription polymerase chain reaction (RT‐qPCR) using samples of 15 GBM cases and 8 dogs with normal gallbladders. Results Comparison of gene expression profiles by RNA‐seq extracted 367 DEGs, including ANO1, a chloride channel associated with changes in mucin morphology, and HTR4, which regulates the function of chloride channels. The ANO1 and HTR4 genes were confirmed to be downregulated in the GBM group by RT‐qPCR. Conclusions and Clinical Importance Our results suggest that GBM may be associated with decreased function of chloride channels expressed in GBECs.

A 9‐month‐old intact crossbred female cat was presented with jaundice, intermittent anorexia and lethargy, increased hepatic enzyme activities, and hyperammonemia. Abdominal ultrasound and computed tomographic examinations determined that the liver had a rounded and irregular margin, and histopathological examination identified excessive accumulation of copper hepatocytes in the liver. Concentrations of both blood and urine copper were higher than in healthy cats. The patient responded well to treatment with penicillamine. Clinicopathological abnormalities and clinical signs improved within 2 months, and the patient was alive for >9 months after starting treatment. Genetic examination determined that the patient and its littermate had a single‐nucleotide variation (SNV, p. T1297R) that impaired the function of the ATP7B gene product; the gene that is mutated in patients with Wilson's disease (WD). Hepatic copper accumulation was believed to be associated with the SNV of the ATP7B gene, and the patient had a genetic disorder of copper metabolism equivalent to WD in humans.

Case summary A 2-year-old spayed female domestic longhair cat was presented for evaluation of chronic ocular discharge and occasional vomiting. While physical examination findings were consistent with an upper respiratory infection (URI), serum chemistry results revealed increased liver enzyme activities. Histopathologic examination of a liver biopsy identified substantial centrilobular accumulation of copper in hepatocytes – strongly suggestive of primary copper hepatopathy (PCH). Retrospective cytologic examination of a liver aspirate also identified copper aggregates in hepatocytes. After transitioning to a low-copper diet, 1 year of chelation therapy with D-penicillamine achieved normalization of liver enzyme activities and resolution of persistent ocular signs. Subsequently, a long-term regimen of zinc gluconate has been successfully managing the cat’s PCH for almost 3 years. Sanger sequencing of the cat’s ATP7B gene, which encodes a copper-transporting protein, revealed a novel, ‘likely pathogenic’, single nucleotide variation (c.3670t/a [p.Trp1224Arg]), for which the cat is heterozygous. Relevance and novel information Recommendations are described for the long-term clinical management of feline PCH – a previously attainable but unreported outcome – with considerations for mitigating the speculated oxidation-exacerbated ocular risks of concurrent URI. This report is the first to include identification of copper aggregates in a liver aspirate from a cat – evidence that liver aspirates from cats could be routinely examined for copper as is standard practice for those from dogs. The cat is also the first reported with PCH and a ‘likely pathogenic’ heterozygous ATP7B genotype, which suggests that normal ATP7B alleles could be recessive to or incompletely/co- dominant with deleterious ATP7B alleles in cats, as has been reported in other species.

Case summary A 14-year-old spayed female American Shorthair cat was presented with weight loss and a palpable abdominal mass. Abdominal ultrasound and CT revealed a duodenal mass with suspected perforation and an enlarged jejunal lymph node. Cytological evaluation from a fine-needle aspiration of the abdominal mass displayed many atypical round cells, some with a small amount of light pink material at the cellular edge. The duodenal mass was surgically removed, and was diagnosed as a plasma cell tumour immunohistochemically positive for CD79 alpha, IgA and lambda immunoglobulin light chains. In addition, amyloidosis was detected. PCR to assess the antigen receptor rearrangement of the tumour cells showed a monoclonal rearrangement of the immunoglobulin heavy chain gene. Postoperatively, the cat received chemotherapy with cyclophosphamide and prednisolone. Owing to progressive enlargement of the jejunal lymph node, different chemotherapy protocols were used sequentially, namely chlorambucil, lomustine and L-asparaginase. However, the cat died 96 days after the initial diagnosis. Post-mortem examination confirmed systemic dissemination of tumour cells. The cause of death was considered to be a result of a complication of the tumour itself and associated amyloidosis. Relevance and novel information This patient was diagnosed with a primary duodenal plasmacytoma, and primary (amyloid light-chain) amyloidosis. In cats, intestinal plasmacytoma is rarely reported and associated amyloidosis is an uncommon feature, when compared with humans. To our knowledge, this is the first clinical report of duodenal plasmacytoma in a cat. The present report shows that feline plasmacytomas should be included in the differential diagnosis of a duodenal mass.

Background Lymphoma with Mott cell change, or Mott cell lymphoma (MCL), is an uncommon variant of canine lymphoma. Because of its rare occurrence, there has been no comprehensive study describing the disease so far. Miniature dachshunds, a popular breed in Japan, sometimes experience MCL. Objectives To investigate the clinical characteristics and outcomes of MCL in miniature dachshunds. Methods Medical records were retrospectively reviewed to identify miniature dachshunds diagnosed with MCL and other types of lymphoma. Data on clinical and laboratory findings, treatments and outcomes were collected. Survival times were compared between miniature dachshunds with MCL and other types of lymphoma. Results Of the 87 miniature dachshunds diagnosed with lymphoma, 9 (10%) had cytological characteristics of MCL. All 9 miniature dachshunds with MCL were categorised as having alimentary lymphoma (small and/or large intestine, 6 dogs; mesenteric lymph node, 3 dogs). The median age was 3.1 years (range, 2.0–9.4 years). All nine dogs were treated with chemotherapeutic protocols used for large cell lymphoma or alkylating agents such as melphalan or chlorambucil. The overall response rate to initial chemotherapy was 78%, and the median progression‐free survival was 105 days. Overall survival in these nine dogs ranged from 6 to >1513 days (median, 240 days), which was significantly longer than in 29 miniature dachshunds with alimentary large cell lymphoma other than MCL (median, 57 days; p = 0.0491). Conclusions MCL in miniature dachshunds can be recognised as a peculiar type of B‐cell lymphoma occurring in relatively young dogs as an alimentary form and has a longer survival compared with typical alimentary large cell lymphoma. The present retrospective study described the clinical characteristics and outcomes of lymphoma with Mott cell change, or Mott cell lymphoma (MCL) in miniature dachshunds. The response rate to initial chemotherapy was 78%, and the median overall survival was 240 days, showing a better prognosis than that of large cell alimentary lymphoma in this study population. MCL in miniature dachshunds can be recognized as a peculiar type of lymphoma which appears to be prevalent in the breed.

Exosomes are small extracellular vesicles released from almost all cell types, which play roles in cell-cell communication. Recent studies have suggested that microenvironmental crosstalk mediated by exosomes is an important factor in the escape of tumour cells from the anti-tumour immune system in human haematopoietic malignancies. Here, we conducted comprehensive analysis of the miRNA and protein profiles within the exosomes released from four canine lymphoid tumour cell lines as a model of human lymphoid tumours. The results showed that the major miRNAs and proteins extracted from the exosomes were similar among the four cell lines. However, the miRNA profiles differed among the exosomes of each cell line, which corresponded to the expression patterns of the parent cells. In the comparison of the amounts of miRNAs and proteins among the cell lines, those of three miRNAs (miR-151, miR-8908a-3p, and miR-486) and CD82 protein differed between exosomes derived from vincristine-sensitive and resistant cell lines. Further investigations are needed to elucidate the biological functions of the exosomal contents in the microenvironmental crosstalk of lymphoid tumours.

Histiocytic sarcoma (HS) is an incurable aggressive tumor, and no consensus has been made on the treatment due to its rare occurrence. Since dogs spontaneously develop the disease and several cell lines are available, they have been advocated as translational animal models. In the present study, therefore, we explored gene mutations and aberrant molecular pathways in canine HS by next generation sequencing to identify molecular targets for treatment. Whole exome sequencing and RNA-sequencing revealed gene mutations related to receptor tyrosine kinase pathways and activation of ERK1/2, PI3K-AKT, and STAT3 pathways. Analysis by quantitative PCR and immunohistochemistry revealed that fibroblast growth factor receptor 1 (FGFR1) is over-expressed. Moreover, activation of ERK and Akt signaling were confirmed in all HS cell lines, and FGFR1 inhibitors showed dose-dependent growth inhibitory effects in two of the twelve canine HS cell lines. The findings obtained in the present study indicated that ERK and Akt signaling were activated in canine HS and drugs targeting FGFR1 might be effective in part of the cases. The present study provides translational evidence that leads to establishment of novel therapeutic strategies targeting ERK and Akt signaling in HS patients.

BackgroundTargeting regulatory T cell (Treg) infiltration is an emerging strategy for cancer immunotherapy. However, its efficacy in advanced prostate cancer remains unclear. Here, we showed the therapeutic efficacy of anti-Treg treatment in a canine model of advanced prostate cancer.MethodsWe used dogs with naturally occurring prostate cancer to study the molecular mechanism underlying Treg infiltration and the effect of anti-Treg treatment. Tumor-infiltrating Tregs was evaluated by immunohistochemistry, and the association with prognosis was examined in dogs with spontaneous prostate cancer. The molecular mechanism of Treg infiltration was explored by RNA sequencing and protein analyses. A non-randomized canine clinical trial was conducted to define the therapeutic potential of anti-Treg treatment for advanced prostate cancer. Human prostate cancer datasets were analyzed to compare gene expression in dogs and humans.ResultsTumor-infiltrating Tregs were associated with poor prognosis in dogs bearing spontaneous prostate cancer. RNA sequencing and protein analyses showed a possible link between the CCL17–CCR4 pathway and the increase of tumor-infiltrating Tregs. Dogs with advanced prostate cancer responded to mogamulizumab, a monoclonal antibody targeting CCR4, with decreased circulating Tregs, improved survival, and low incidence of clinically relevant adverse events. Urinary CCL17 concentration and BRAFV595E mutation were independently predictive of the response to mogamulizumab. Analysis of a transcriptomic dataset of human prostate cancer showed that the CCL17–CCR4 axis correlated with Foxp3. In silico survival analyses revealed that high expression of CCL17 was associated with poor prognosis. Immunohistochemistry confirmed that tumor-infiltrating Tregs expressed CCR4 in human patients with prostate cancer.ConclusionsAnti-Treg treatment, through CCR4 blockade, may be a promising therapeutic approach for advanced prostate cancer in dogs and some population of human patients.

We tested the hypotheses that hypoxic stimulation enhances growth potentials of canine lymphoma cells by activating hypoxia-inducible factor 1α (HIF-1α), and that the hypoxia-activated prodrug (TH-302) inhibits growth potentials in the cells. We investigated how hypoxic culture affects the growth rate, chemoresistance, and invasiveness of canine lymphoma cells and doxorubicin (DOX)-resistant lymphoma cells, and influences of TH-302 on survival rate of the cells under hypoxic conditions. Our results demonstrated that hypoxic culture upregulated the expression of HIF-1α and its target genes, including ATP-binding cassette transporter B1 (ABCB1), ATP-binding cassette transporter G2 (ABCG2), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and survivin, and enhanced the growth rate, DOX resistance, and invasiveness of the cells. Additionally, TH-302 decreased the survival rate of the cells under hypoxic condition. Our studies suggest that hypoxic stimulation may advance the tumorigenicity of canine lymphoma cells, favoring malignant transformation. Therefore, the data presented may contribute to the development of TH-302-based hypoxia-targeting therapies for canine lymphoma.

Large cell gastrointestinal lymphoma (LCGIL) is the most common extranodal lymphoma in dogs, but its molecular biological backgrounds have not been clarified. In this study, we comprehensively investigated the gene mutations in LCGIL. Whole exome sequencing analysis using four dogs with LCGIL showed mutations in NACC1 gene in two dogs. Further, the six genes known to be mutated in human intestinal T-cell lymphoma, ASXL3, SOCS3, PRDM1, FYN, TET2, and ZDBF2, were found to be mutated in one dog. Then, targeted next-generation sequencing analysis was performed to validate these results using additional 31 dogs with LCGIL. As a result, the mutation in ZDBF2 genes were identified in all samples, but the same mutation was ubiquitously observed in all peripheral blood samples. As for the remaining genes, the mutations were not observed in any dogs. The targeted next-generation analysis of whole exon regions of ZDBF2 revealed the other mutations in additional three dogs. In the present study, some mutations in genes related to human intestinal T-cell lymphoma were identified, but common gene mutations were not found among most cases. These results implied the heterogeneity of molecular pathophysiology of canine LCGIL. Further studies are needed to comprehensively analyze genomic and non-genomic molecular aberrations in each canine LCGIL case.