A frameshift variant in the EXT1 gene in a feline leukemia virus-negative cat with osteochondromatosis.

Osteochondromatosis is a benign proliferative disorder characterized by cartilage-capped bony protuberances. In humans and most mammals, variants in the EXT1 or EXT2 gene are strongly correlated with the etiology of osteochondromatosis. However, in cats, osteochondromatosis has only been associated with feline leukemia virus infection. In this study, to explore other factors involved in the etiology of feline osteochondromatosis, we examined the EXT1 and EXT2 genes in a feline leukemia virus-negative cat with osteochondromatosis. Genetic analysis revealed a heterozygous single base pair duplication in exon 6 of the EXT1 gene (XM_023248762.2:c.1468dupC), leading to a premature stop codon in the EXT1 protein. Notably, this frameshift variant is recognized as one of the most common pathogenic variants in human osteochondromatosis. Our data suggest for the first time that genetic variants can have etiologic roles in osteochondromatosis in cats, as in humans and other animals.

Efficacy and adverse events of anthracycline and propranolol combination in five dogs with stage 3 hemangiosarcoma.

Background: Canine hemangiosarcoma (HSA), which originates from endothelial cells, is one of the most common malignant neoplasms that frequently develop metastatic lesions. Although anthracycline-based HSA treatment strategies have been widely investigated, reliable therapy for dogs with clinically advanced-stage HSA (stage 3 HSA) has not been established yet. Recently, several studies have demonstrated that propranolol, a beta-adrenergic receptor antagonist, exhibits anti-tumor effects against tumors originating from vascular endothelial cells, indicating the possibility that propranolol is a candidate adjunctive agent for anthracycline-based therapy in dogs with stage 3 HSA. This study aimed to evaluate the clinical efficacy and adverse events (AEs) of anthracycline and propranolol combination in stage 3 HSA-affected dogs. Case Description: We retrospectively investigated five dogs diagnosed with stage 3 HSA which were administered with both anthracycline and propranolol during the same period between January 2020 and August 2021. Clinical benefit was observed in four of five HSA dogs (one of complete response, one of partial response, and two of stable disease) with gross metastatic lesions by anthracycline and propranolol combination. Notably, some or all of the metastatic lesions were reduced in two cases. In all five dogs administered with anthracycline and propranolol combination, no serious and irreversible AEs were observed. Conclusion: Our findings demonstrate the efficacy and safety of anthracycline and propranolol combination in stage 3 HSA-affected dogs. Further studies are needed to establish treatment protocols based on anthracycline and propranolol combination for dogs with advanced HSA.

Computed tomography-based evaluation for normal adrenal gland size independent of body weight in dogs.

Background: Computed tomography (CT) is useful for evaluating the anatomical position of the adrenal gland and the presence of adrenal tumor (AT) metastasis or vascular invasion from ATs. Aim: To determine a weight-independent reference for adrenal gland size in normal dogs using CT. Methods: The medical records database of Gifu University was searched for data collected from April 2010 to December 2015 for records of dogs that underwent abdominal CT. The CT images were retrospectively analyzed using a Digital Imaging and Communications in Medicine viewer. The ratios of the minor axes of the adrenal glands to the height of the spinal cavity were investigated. Results: In total, 939 dogs were included. The left and right adrenal minor axes showed a moderate positive correlation with body weight (right: r = 0.61, p < 0.05; left: r = 0.54, p < 0.05). The L4 spinal cavity height showed a strong positive correlation with body weight (r = 0.82, p < 0.05). The left and right adrenal minor axis/L4 spinal cavity ratio did not correlate with body weight (right: r = 0.02, p = 0.53; left: r = -0.082, p < 0.05). The 95% confidence intervals of the adrenal minor axis/L4 spinal cavity ratios were as follows: right: 0.5-1.3 and left: 0.5-1.4. Conclusion: These results indicate that the adrenal minor axis/L4 spinal cavity ratio can be used as an index of adrenal gland size that is not affected by body weight. Patients in whom the adrenal minor axis/L4 spinal cavity ratio exceeds the upper limit (right 1.3, left 1.4) may have adrenal swelling.

First Evidence of Familial Transmission of Hereditary Gastrointestinal Polyposis Associated with Germline APC Variant in Jack Russell Terriers.

Jack Russell terriers (JRTs) with gastrointestinal (GI) neoplastic polyps have been recently reported to harbor an identical germline variant in the adenomatous polyposis coli (APC) gene, c.[462_463delinsTT], in the heterozygous state, which indicates that this disease is an autosomal dominant hereditary disorder. Many individual cases of this disease have been observed in clinical practice; however, familial transmission has not been demonstrated due to the difficulty in tracing the family members of household dogs, especially after the disease's onset in adulthood. Recently, we encountered two cases of GI polyposis in maternal half sisters. These two cases facilitated the identification of additional relatives spanning three generations, including parents, full and half siblings of the dam (aunt and uncle), littermate and non-littermate siblings, and a nephew. Genetic analysis revealed that 11 of the 14 examined JRTs in this family carried the heterozygous germline APC variant, and eight dogs with the variant already had a current and/or past medical history of GI neoplastic polyps. Some cases in the family showed significantly more severe disease phenotypes than those initially reported, suggesting that the severity of this disease can vary considerably among individuals. Moreover, familial aggregation of severe cases suggested that the genetic modifier involved in increasing severity may have been transmitted in this family in addition to the germline APC variant. Furthermore, in addition to this family, we reported two other families of JRTs affected by hereditary GI polyposis that consisted of five full and half siblings and a mother-daughter pair, respectively. These findings unequivocally establish the transgenerational transmission of hereditary GI polyposis associated with the germline APC variant in JRT lineages.

Therapeutic applications of local injection of hsa-miR-634 into canine spontaneous malignant melanoma tumors.

Malignant melanoma (MM) is one of the most common tumors in both dogs and humans. As canine MM (CMM) and human MM (HMM) have similar clinical characteristics, CMM appears to be a good clinical model for HMM. We previously demonstrated that the introduction of a synthetic double-strand-microRNA-634 (miR-634) mimic triggered apoptotic cell death by directly targeting the genes associated with cytoprotective processes in various human cancer cell lines, including those of HMM. This study aimed to investigate the antitumor effects of the local administration of miR-634 on spontaneous CMMs to provide a basis for future applications of miR-634 formulations in HMM treatment. We found that miR-634 administration induced apoptosis in CMM cell lines in vitro via downregulation of Asct2, Nrf2, and survivin expression, similar to the mechanisms in HMM cell lines. Furthermore, intratumoral miR-634 administration induced antitumor effects in four of seven spontaneous CMM cases, with no adverse effects. Local administration of miR-634 to lung metastasis under ultrasound guidance induced tumor shrinkage. These results confirm the antitumor effect of the local administration of miR-634 in spontaneous CMM, a model for spontaneous HMM, thereby providing a novel treatment strategy for HMM.

The effects of BPA-BNCT on normal bone: determination of the CBE value in mice‡.

Boron neutron capture therapy (BNCT) with p-boronophenylalanine (BPA) is expected to have less effect on the decrease in normal bone strength than X-ray therapy. However, the compound biological effectiveness (CBE) value necessary to convert the boron neutron capture reaction (BNCR) dose into a bioequivalent X-ray dose has not been determined yet. The purpose of this study was to evaluate the influence of BNCT on normal bone in mice and to elucidate the CBE factor. We first searched the distribution of BPA in the normal bone of C3H/He mice and then measured the changes in bone strength after irradiation. The CBE value was determined when the decrease in bone strength was set as an index of the BNCT effect. The 10B concentrations in the tibia after subcutaneous injection of 125, 250 and 500 mg/kg BPA were measured by prompt gamma-ray spectroscopy and inductively coupled plasma (ICP)-atomic emission spectrometry. The 10B mapping in the tibia was examined by alpha-track autoradiography and laser ablation-ICP-mass spectrometry. The 10B concentration increased dose-dependently; moreover, the concentrations were maintained until 120 min after BPA administration. The administered 10B in the tibia was abundantly accumulated in the growth cartilage, trabecular bone and bone marrow. The bone strength was analyzed by a three-point bending test 12 weeks after irradiation. The bending strength of the tibia decreased dose-dependently after the irradiation of X-ray, neutron and BNCR. The CBE factor was obtained as 2.27 by comparing these dose-effect curves; the value determined in this study will enable an accurate dosimetry of normal bone.

Feasibility study for inducing the skeletal muscle fibrosis via irradiation using two mouse strains.

PURPOSE: Although the mechanism of onset and progression of radiation-induced fibrosis (RIF) has been studied, most studies to date have focused on pulmonary fibrosis. There are few studies on murine RIF in the skeletal muscle, and the pathogenic mechanism remains unclear. This pilot study aimed to evaluate the feasibility to create a murine model of RIF in the skeletal muscle and analyze strain differences in fibrosis sensitivity. MATERIALS AND METHODS: Two mouse strains, C57BL/6 and C3H/He, were used. Their right hind limbs were irradiated at a dose of 25 Gy once a week for three fractions. Gastrocnemius muscles were collected at day 4, and weeks 2, 4, 8, 12, and 24 after the third irradiation and subjected to histopathological examination and immunoblotting. RESULTS: In C57BL/6 mice, chronic inflammation and an increased expression of transforming growth factor-ß (TGF-ß) and fibronectin were observed 2 weeks after irradiation. A significant increase in fibrosis was detected after 8 weeks. However, in C3H/He mice, the expression of TGF-ß and fibronectin increased 8 weeks after irradiation, and fibrosis significantly increased after 12 weeks. Moreover, the degrees of inflammation and fibrosis were more remarkable in C57BL/6 mice than in C3H/He mice. CONCLUSION: The onset and degree of fibrosis may be associated with the expression of TGF-ß and fibronectin, and inflammation, in a strain-specific manner. Therefore, a murine model of RIF in the skeletal muscle could be created using the indicated method, suggesting that the C57BL/6 strain is more sensitive to fibrosis in the skeletal muscle, as well as the lung, than the C3H/He strain. Radiation-induced fibrosis in the skeletal muscle could be detected in C57BL/6 and C3H/He mice, with C57BL/6 mice being more sensitive to fibrosis in the skeletal muscle than C3H/He mice.

Intraperitoneal administration of synthetic microRNA-214 elicits tumor suppression in an intraperitoneal dissemination mouse model of canine hemangiosarcoma.

Canine hemangiosarcoma (HSA) has an extremely poor prognosis, making it necessary to develop new systemic treatment methods. MicroRNA-214 (miR-214) is one of many microRNAs (miRNA) that can induce apoptosis in HSA cell lines. Synthetic miR-214 (miR-214/5AE), which showed higher cytotoxicity and greater nuclease resistance than mature miR-214, has been developed for clinical application. In this study, we evaluated the effects of miR-214/5AE on stage 2 HSA in a mouse model. Mice intraperitoneally administered with miR-214/5AE (5AE group) had significantly fewer intraperitoneal dissemination tumor foci (median number: 72.5 vs. 237.5; p < 0.05) and a lower median foci weight (0.26 g vs. 0.61 g; p < 0.05). Mice in the 5AE group had increased expression of p53 and cleaved caspase-3, and a significantly lower proportion of Ki-67-positive cells, than those in the non-specific miR group. Notably, no significant side effects were observed. These results indicate that intraperitoneal administration of miR-214/5AE exhibits antitumor effects in an intraperitoneal dissemination mouse model of HSA by inducing apoptosis and suppressing cell proliferation. These results provide a basis for future studies on the antitumor effect of miR-214/5AE for HSA.

Development of synthetic microRNA-214 showing enhanced cytotoxicity and RNase resistance for treatment of canine hemangiosarcoma.

MicroRNA-214 (miR-214), a pivotal tumour-suppressive miRNA, is downregulated in canine hemangiosarcoma (HSA) cells. Although these tumour-suppressive miRNAs are potential therapeutic agents, their clinical efficacy may be limited because of their vulnerability to RNase-rich microenvironments and low in vivo transfection rates. We developed synthetic miR-214s with enhanced cytotoxicity, RNase resistance and quantity of miR-214 in/on cells. These synthetic miR-214s were synthesized by various chemical modifications (such as 4'-aminoethyl-2'-fluoro, 2'-fluoro, 2'-O-methyl, phosphorothioate and oligospermine modifications) of the wild-type mature miR-214 sequences. Transfection of HSA cells with synthetic miR-214 (miR-214 5AE) demonstrated significant growth suppressive effect and induced the strongest apoptotic response. Synthetic miR-214s (miR-214 5AE, miR-214 10AE and miR-214 OS) were much more stable than mature miR-214s in foetal bovine serum. Similar to mature miR-214, 5AE and OS suppressed the expression level of COP1 in HSA cells. The quantity of synthetic miR-214s in/on cells was higher than that of mature miR-214. In conclusion, we developed a clinically applicable, synthetic miR-214 5AE that regulates the COP1 protein expression similar to that mediated by mature miR-214. Additionally, miR-214 5AE confers better cytotoxicity, nuclease resistance and transfection rate than mature miR-214. Thus, miR-214 5AE could potentially be a novel miRNA-based chemotherapeutic agent that could improve the prognosis of HSA. Its in vivo effects on canine HSA need to be examined in future.

Synthetic microRNA-205 exhibited tumour suppression in spontaneous canine malignant melanoma by intratumoral injection.

MicroRNAs (miRNA) are small, noncoding RNA molecules consisting of 18 to 25 nucleotides. Malignant melanomas (MMs) are one of the most common malignancies in both dogs and humans. We previously reported that chemically modified synthetic miRNA-205 (miR-205BP/S3) inhibits melanoma growth in vitro and in vivo. The present study aimed to evaluate the efficacy of intratumoral administration of synthetic miR-205 for spontaneous CMMs and to evaluate its potential as systemic therapy. Ten dogs with various stages of MM were treated with miR-205BP/S3 injected into tumours. Adverse effects (AEs) were assessed in accordance with the Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events (VCOG-CTCAE) v1.1 guidelines. Five cases attained complete remission (CR), three attained stable disease (SD), and two cases displayed characteristics of progressive disease (PD). In all cases, no changes were observed in the blood parameters upon miRNA administration, and miR-205BP/S3 administration did not yield any side effects. The present results suggest that intratumoral administration of miR-205BP/S3 is a potentially applicable treatment for canine melanoma.

Survival analysis in dogs with urinary transitional cell carcinoma that underwent whole-body computed tomography at diagnosis.

This retrospective study aimed to evaluate factors associated with survival and to compare characteristics between tumour localizations in dogs with urinary transitional cell carcinoma (TCC) that underwent whole-body computed tomography (CT) at diagnosis. Dogs with histologically confirmed TCC that received medical therapy between 2010 and 2017 were included; dogs that underwent surgery or radiotherapy for the primary tumour were excluded. According to the CT findings, primary tumour localization (classified into the Bladder, Urethra and Bladder and Urethra groups), prostate involvement, iliosacral lymphadenomegaly, sternal lymphadenomegaly and metastasis to the bone and lung were evaluated for survival analysis. CT at diagnosis revealed iliosacral lymphadenomegaly, sternal lymphadenomegaly, bone metastasis and lung metastasis in 47.7%, 18.5%, 24.6% and 35.4% of the 65 included dogs, respectively. The overall median survival time was 196 days. On multivariable analysis, TCC localization (hazard ratio [HR], 1.90; P = .037), bone metastasis (HR, 2.76; P = .013) and sternal lymphadenomegaly (HR, 3.56; P = .004) were significantly associated with survival. Compared to the Bladder group (n = 16), the Urethra group (n = 26) had higher metastasis rates to the bone (6.3% vs 42.3%; P = .045) and lung (6.3% vs 46.2%; P = .022). The survival time was shorter in the Urethra group than in the Bladder group (121.5 vs 420 days; P < .001), and it was similar only in female dogs (247 vs 420 days; P = .031). These findings suggest that whole-body CT could be valuable for predicting the prognosis in urinary TCC.