Anti-tumor effect of proteasome inhibitor on canine urothelial carcinoma

Canine urothelial carcinoma (cUC) is one of the most malignant tumors affecting dogs; however, its proliferative mechanism is yet to be fully elucidated. The ubiquitin-proteasome system (UPS) is an important metabolic pathway regulating protein degradation, and its dysfunction leads to apoptosis. We investigated the antitumor effect of the proteasome inhibitor bortezomib, which blocks the UPS. Bortezomib inhibited cell growth in cUC cell lines by inducing apoptosis in vitro. These findings suggest the potential of bortezomib as a novel therapeutic drug for dogs with cUC.

Diagnostic Value of Conventional Polymerase Chain Reaction for Detecting BRAF V595E Mutation in Liquid and Tissue Specimens of Canine Urothelial and Prostate Carcinomas

Canine urothelial carcinoma (UC) and prostatic carcinoma (PC) often present diagnostic challenges due to their anatomical locations. The BRAF V595E mutation, analogous to the human BRAF V600E mutation, has been identified in UC and PC. Digital PCR of urine is a non-invasive diagnostic method of mutation detection, but the availability of the necessary equipment is limited. This study aimed to develop a conventional PCR to detect the BRAF V595E mutation in urine and prostatic wash specimens from dogs with UC or PC. Specific primers for detecting wild-type and mutant BRAF V595E genes were validated in 34 formalin-fixed paraffin-embedded (FFPE) tissues, 116 urine samples, and 9 prostatic wash specimens. The results showed that the BRAF V595E mutation detection rate for UC and PC in the tissues was 51.6%. The detection rate in liquid specimens from dogs with lower urinary tract or prostate masses was 53.2%. Of the 41 cases with follow-up, 16 were further diagnosed with UC or PC, with 75% of liquid specimens from these dogs showing the BRAF V595E mutation. This conventional PCR method provides a reliable and non-invasive screening tool for UC and PC in dogs, especially in settings without advanced equipment.

Bioprinted research models of urological malignancy

Urological malignancy (UM) is among the leading threats to health care worldwide. Recent years have seen much investment in fundamental UM research, including mechanistic investigation, early diagnosis, immunotherapy, and nanomedicine. However, the results are not fully satisfactory. Bioprinted research models (BRMs) with programmed spatial structures and functions can serve as powerful research tools and are likely to disrupt traditional UM research paradigms. Herein, a comprehensive review of BRMs of UM is presented. It begins with a brief introduction and comparison of existing UM research models, emphasizing the advantages of BRMs, such as modeling real tissues and organs. Six kinds of mainstream bioprinting techniques used to fabricate such BRMs are summarized with examples. Thereafter, research advances in the applications of UM BRMs, such as culturing tumor spheroids and organoids, modeling cancer metastasis, mimicking the tumor microenvironment, constructing organ chips for drug screening, and isolating circulating tumor cells, are comprehensively discussed. At the end of this review, current challenges and future development directions of BRMs and UM are highlighted from the perspective of interdisciplinary science.

Large-scale genomic analysis of the domestic dog informs biological discovery

Recent advances in genomics, coupled with a unique population structure and remarkable levels of variation, have propelled the domestic dog to new levels as a system for understanding fundamental principles in mammalian biology. Central to this advance are more than 350 recognized breeds, each a closed population that has undergone selection for unique features. Genetic variation in the domestic dog is particularly well characterized compared with other domestic mammals, with almost 3000 high-coverage genomes publicly available. Importantly, as the number of sequenced genomes increases, new avenues for analysis are becoming available. Herein, we discuss recent discoveries in canine genomics regarding behavior, morphology, and disease susceptibility. We explore the limitations of current data sets for variant interpretation, tradeoffs between sequencing strategies, and the burgeoning role of long-read genomes for capturing structural variants. In addition, we consider how large-scale collections of whole-genome sequence data drive rare variant discovery and assess the geographic distribution of canine diversity, which identifies Asia as a major source of missing variation. Finally, we review recent comparative genomic analyses that will facilitate annotation of the noncoding genome in dogs.

Effects of trastuzumab emtansine on canine urothelial carcinoma cells in vitro and in vivo

Urothelial carcinoma (UC) is the most common malignancy of the urinary tract in dogs and has aggressive behaviour. Although human epidermal growth factor receptor 2 (HER2) is a known therapeutic target with evidence in canine UC, the efficacy of anti-HER2 antibody drugs remains unknown. This study aimed to investigate the effects of anti-HER2 antibody drugs including trastuzumab and trastuzumab emtansine (T-DM1) on canine UC cell lines in vitro and in vivo. Four canine UC cell lines (Nene, TCCUB, Love, and Sora) were used. In western blotting, HER2 protein expression was observed in all the cell lines. Although both trastuzumab and T-DM1 showed dose-dependent growth inhibitory activity in the cell lines, T-DM1 showed much stronger activity than that of trastuzumab. In flow cytometry analyses with the canine UC cell line (Sora), T-DM1 but not trastuzumab significantly increased the percentages of early and late apoptotic cells in annexin V apoptotic assays and the sub-G1 phase fraction in cell cycle analyses. For the in vivo experiment, the canine UC cells (Sora) were subcutaneously injected into nude mice. Four days after inoculation, trastuzumab, T-DM1, or vehicle was administered intraperitoneally once a week for three times. Tumour volumes were significantly smaller in the T-DM1 group compared to the trastuzumab and vehicle control groups. These findings indicate that T-DM1 exerts a stronger antitumour effect than that of trastuzumab on canine UC cells in vitro and in vivo, possibly by inducing apoptosis due to DM1.

Urinary and household chemical exposures in pet dogs with urothelial cell carcinoma

Urothelial cell carcinoma (UCC) has been linked to environmental chemical exposures in people, but these risk factors are not well understood in dogs with UCC. We hypothesised that household chemical exposures contribute to the risk of UCC in pet dogs. This prospective cross-sectional case-control study included 37 dogs with UCC and 37 unaffected breed-, sex-, and age-matched controls. Dog owners completed an environmental questionnaire and household samples were collected and analysed for arsenic (in tap water and room dust) and acrolein (in room air). Urine samples from UCC dogs, control dogs, and consenting owners were analysed for inorganic arsenic species, the acrolein metabolite 3-HPMA, and the phenoxy herbicide 2,4-D. Public data on chlorination byproducts (total trihalomethanes) in municipal drinking water were also compared between case and control households. Dogs with UCC were more likely to swim in a pool (15.2%) compared with control dogs (0%) (OR 1.69, 95% CI = 1.69-∞; p = .02). Dogs with UCC also had more than 4-fold higher reported municipal water concentrations of chlorination byproducts (median 28.0 ppb) compared with controls (median 6.9 ppb; p < .0001). Dust arsenic concentrations were unexpectedly lower in case households (median 0.277 ng/cm2) compared with control households (median 0.401 ng/cm2; p = .0002). Other outcomes were not significantly different between groups. These data suggest that dog owners, especially those of breeds known to be at higher risk for UCC, consider limiting access to swimming pools and installing water filtration units that remove total trihalomethanes.

Genome-wide analyses reveals an association between invasive urothelial carcinoma in the Shetland sheepdog and NIPAL1

Naturally occurring canine invasive urinary carcinoma (iUC) closely resembles human muscle invasive bladder cancer in terms of histopathology, metastases, response to therapy, and low survival rate. The heterogeneous nature of the disease has led to the association of large numbers of risk loci in humans, however most are of small effect. There exists a need for new and accurate animal models of invasive bladder cancer. In dogs, distinct breeds show markedly different rates of iUC, thus presenting an opportunity to identify additional risk factors and overcome the locus heterogeneity encountered in human mapping studies. In the association study presented here, inclusive of 100 Shetland sheepdogs and 58 dogs of other breeds, we identify a homozygous protein altering point mutation within the NIPAL1 gene which increases risk by eight-fold (OR = 8.42, CI = 3.12-22.71), accounting for nearly 30% of iUC risk in the Shetland sheepdog. Inclusion of six additional loci accounts for most of the disease risk in the breed and explains nearly 75% of the phenotypes in this study. When combined with sequence data from tumors, we show that variation in the MAPK signaling pathway is an overarching cause of iUC susceptibility in dogs.

Comparative aspects of targeted sentinel lymph node mapping in veterinary and human medicine: opportunities for future research

There is a significant overlap in the genetic, metabolic and epigenetic alterations between human and companion animal cancers, including those of the oral cavity, breast, bladder, skin, lungs and pancreas. In many cancer types, the identification and removal of affected lymph nodes are essential for accurate cancer management, including treatment and prognosis. Historically, lymphadenectomy and subsequent radical resection based on regional anatomy, palpation and lymph node aspirates were considered sufficient; however, modern approaches with sentinel lymph node mapping (SLN) mapping have increased the accuracy of surgical decision-making. Preoperative and intraoperative SLN mapping techniques in veterinary patients parallel those used in human medicine. While many of these techniques are highly successful, the main challenges with current methodologies are their sensitivity and specificity for the presence of cancer, which can be overcome via precision medicine and targeted SLN mapping agents. Given the large population of dogs and cats with cancer, the crossover of knowledge between species can help to deepen our understanding of many of these cancers and can be useful in evaluating new drugs and/or therapies. In this review, we discuss SLN mapping techniques in veterinary medicine and the concept of precision medicine as it relates to targeted SLN mapping imaging agents. The large number of companion animals affected by cancer is an underutilized resource to bridge the translational gap and we aim to provide a reference for the use of dogs and cats as a comparative model for human SLN mapping.

Feasibility of laparoscopic stapled partial cystectomy in canine cadavers

OBJECTIVE

To describe a technique for laparoscopic partial cystectomy and evaluate sealing of canine urinary bladder tissue with an endoscopic stapler.

STUDY DESIGN

Prospective, cadaveric study.

SAMPLE POPULATION

Eleven canine cadavers.

METHODS

Laparoscopic partial cystectomy was performed with an endoscopic gastrointestinal anastomosis (GIA) stapler. Leak testing and urodynamic evaluation was performed to measure intravesical pressure at initial leakage and catastrophic failure or the maximum pressure at which intravesical pressure plateaued. Surgical time, complications, and site of leakage were also recorded.

RESULTS

Laparoscopic partial cystectomy was successfully performed in 10 of 11 cadavers. Median procedure time was 13.6 min (10.1-15.2 min). Median intravesical pressure at initial leakage was 31 mmHg (28-56 mmHg) with a median increase from initial pressure of 15 mmHg (11-37 mmHg). No catastrophic failure of the cystectomy site was observed during leak testing. Intravesical pressure plateaued at a median of 52 mmHg (39-73 mmHg), which was a median of 13 mmHg (8-23 mmHg) higher than intravesical pressure at initial leakage. The median total volume infused at the time of plateau of intravesical pressure was 89 mL (58-133 mL).

CONCLUSION

Laparoscopic stapled partial cystectomy was feasible in canine cadavers. Endoscopic GIA staplers appear to seal the canine urinary bladder with minimal leakage.

CLINICAL SIGNIFICANCE

Use of an endoscopic GIA stapler may provide a minimally invasive option for partial cystectomy in dogs. Further evaluation for application to clinical cases is warranted.

Pan-tumour analysis of COX-2 expression in dogs

Cyclooxgenase-2 (COX-2) is associated with inflammatory microenvironment and tumour progression. COX-2 expression was reported in canine tumours, and anti-COX treatment showed therapeutic effects in selected tumour types. Currently, direct comparisons between different tumour types or reports were impossible due to varying evaluation protocols. Additionally, COX-2 expression in relatively uncommon tumours were yet to be evaluated. Here, we analysed COX-2 expression across various tumour types in dogs in a consistent protocol, aiming to revisit accumulated evidence in the field and report novel candidate tumours for anti-COX therapy. COX-2 expression in 32 histological types of tumours, which consisted of 347 samples in total, was investigated using immunohistochemistry followed by the Belshaw's method scoring (range: 0-12). More than the half of the samples expressed COX-2 in mast cell tumours, transitional cell carcinoma in the urinary tract, squamous cell carcinoma, liposarcoma, and melanoma, with COX-2 median scores ranging from 1-8. On the other hand, <20% tissues expressed COX-2 in the half of tumour types investigated. Overall COX-2 positive rate was 27%. In conclusion, the results confirmed COX-2 expression in the well-known COX-2-expresing tumour types and suggested novel candidate tumours for anti-COX-2 therapy. At the same time, overall COX-2 expression was low, and inter- and intra-histology heterogeneity was apparent. This study will provide a foundation reference for future research in canine tumours.

Reason for euthanasia in dogs with urothelial carcinoma treated with chemotherapy or radiation therapy or both: A retrospective observational study

BACKGROUND

Clients want to know the ultimate cause of death in their pet after cancer treatment. The cause of euthanasia and investigation of urinary obstruction in treated dogs with urothelial carcinoma (UC) has not been specifically reported in veterinary literature.

HYPOTHESIS/OBJECTIVES

Our hypothesis was that the majority of treated dogs with UC are euthanized secondary to primary tumor factors, such as urinary obstruction.

ANIMALS

Fifty-nine client-owned dogs diagnosed with UC.

METHODS

Retrospective observational study on clinical signs and disease at euthanasia of dogs with UC treated by radiation therapy or chemotherapy or both.

RESULTS

The median overall survival time (OST) of all dogs was 339 days (range, 17-1996; 95% confidence interval [CI], 185-392; interquartile range [IQR], 112-505). Of dogs deemed to have been euthanized because of UC (50/59, 85%), the primary cause was considered to be local progression in 31/50 (62%), most often because of perceived complete or partial urinary obstruction (24/31, 77%). No variables were found to be predictive of urinary obstruction. The overall documented metastatic rate was 56%. In dogs euthanized because of UC, metastasis was deemed to be the cause in 19/50 (38%) dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Regardless of the type of treatment, UC in dogs has a poor prognosis and there is a continuing need to improve treatments that focus on local control of the primary tumor, given its high contribution to the decision for euthanasia. Proactive management to avoid the high frequency of urinary obstruction may be worthy of future investigation.

Clinicopathologic Characterization of Prostatic Cancer in Dogs

Clinicopathologic data in dogs with prostate cancer (PCa) may aid in the differentiation between tumor types and subsequent treatment decisions; however, these data are often unreported. Demographic, clinicopathologic, cytologic, histologic and survival data from dogs with primary prostatic adenocarcinoma (PRAD) (n = 56) and primary prostatic transitional cell carcinoma (P-TCC) (n = 74) were acquired from a tertiary veterinary teaching hospital from 1992 to 2022. Red blood cell distribution width (RDW) to albumin ratio (RAR) was evaluated for diagnostic utility in differentiating between PRAD and P-TCC. Sections from PRAD tumors (n = 50) were stained for androgen receptor (AR) expression, and laboratory data were compared between AR positive (AR+) and AR negative (AR-) groups. RDW was increased in PRAD, while albumin was decreased (p < 0.05). P-TCC was associated with Melamed-Wolinska bodies (MWB) and necrosis on cytology (p < 0.05). RAR had acceptable diagnostic utility in the differentiation of PCa tumors (AUC = 0.7; p < 0.05). Survival rates and metastases were equivocal. AR+ and AR- PRAD tumors did not differ in clinicopathologic data or survival (p > 0.05). In conclusion, hypoalbuminemia was significantly associated with PRAD and decreased survival, while MWB and necrosis were significantly associated with P-TCC on cytology. These clinicopathologic data may help clinicians differentiate between these tumors ante mortem to guide appropriate treatment and intervention.

Assessment of Tumor-Associated Tissue Eosinophilia (TATE) and Tumor-Associated Macrophages (TAMs) in Canine Transitional Cell Carcinoma of the Urinary Bladder

Transitional cell carcinoma of the urinary bladder is a significant neoplasm in dogs, characterized by a poor prognosis and a high metastatic potential. These canine spontaneous tumors share many characteristics with human transitional cell carcinoma, making them an excellent comparative model. The role of inflammatory infiltration in tumor development and progression is frequently contradictory, especially concerning tumor-associated tissue eosinophils (TATE) and tumor-associated macrophages (TAMs). This study aims to analyze TATE and TAMs in canine transitional cell carcinoma of the urinary bladder. Congo Red staining was used to identify TATE, and immunohistochemistry was performed to detect TAMs in 34 cases of canine transitional cell carcinoma of the bladder carcinomas, categorized into low and high grades. Statistically significant differences were observed between the number of eosinophils and macrophages in the two groups of tumors. The number of TATE was higher in low-grade malignant tumors, but the number of TAMs was higher in high-grade tumors. Our findings suggest the importance of TATEs and TAMs in the aggressiveness of canine transitional cell carcinoma and propose their potential use as therapeutic targets.

Design of a randomized, placebo-controlled study evaluating efficacy and safety of a cancer preventative vaccine in dogs

Preventative anti-cancer vaccination strategies have long been hampered by the challenge of targeting the diverse array of potential tumor antigens, with successes to date limited to cancers with viral etiologies. Identification and vaccination against frameshift neoantigens conserved across multiple species and tumor histologies is a potential cancer preventative strategy currently being investigated. Companion dogs spontaneously develop cancers at a similar incidence to those in people and are a complementary comparative patient population for the development of novel anti-cancer therapeutics. In addition to an intact immune system with tumors that arise in an autochthonous tumor microenvironment, dogs also have a shorter lifespan and temporally compressed tumor natural history as compared to humans, which allows for more rapid evaluation of safety, immunogenicity, and efficacy of cancer vaccination strategies. Here we describe the study protocol for the Vaccination Against Canine Cancer Study (VACCS), the largest interventional cancer clinical trial conducted in companion dogs to date. In addition to safety and immunogenicity, the primary endpoint of VACCS is the cumulative incidence (CI) of dogs developing malignant neoplasia of any type at the end of the study period. Secondary endpoints include changes in incidence of specific tumor types, survival times following neoplasia diagnosis, and all-cause mortality.

Canine urothelial carcinoma: a pilot study of microRNA detection in formalin-fixed, paraffin-embedded tissue samples and in normal urine

We assessed the effects of fixation time in formalin and inclusion of surrounding tissue on microRNA (miRNA) cycle quantification (Cq) values in formalin-fixed, paraffin-embedded (FFPE) urothelial carcinoma (UC) tissue (n = 3), and the effect of conditions on miRNAs in urine from 1 healthy dog. MiRNAs were extracted using commercial kits and quantified using miRNA-specific fluorometry in normal bladder tissue scrolls, UC tissue cores, and bladder muscularis tissue cores from 4 FFPE bladder sections (3 UCs, 1 normal), plus 1 UC stored in formalin for 1, 8, 15, and 22 d before paraffin-embedding. Urine was collected from a healthy dog on 4 occasions; 1-mL aliquots were stored at 20, 4, -20, and -80°C for 4, 8, 24, and 48 h, and 1 and 2 wk. For both FFPE tissue and urine, we used reverse-transcription quantitative real-time PCR (RT-qPCR) to quantify miR-143, miR-152, miR-181a, miR-214, miR-1842, and RNU6B in each tissue or sample, using miR-39 as an exogenous control gene. The Cq values were compared with ANOVA and t-tests. The time of tissue-fixation in formalin did not alter miRNA Cq values; inclusion of the muscularis layer resulted in a statistically different miRNA Cq profile for miR-152, miR-181a, and RNU6B in bladder tissue. MiRNAs in acellular urine were stable for up to 2 wk regardless of the storage temperature. Our findings support using stored FFPE and urine samples for miRNA detection; we recommend measuring miRNA only in the tissue of interest in FFPE sections.

Evaluation of the safety and feasibility of electrochemotherapy with intravenous bleomycin as local treatment of bladder cancer in dogs

Local treatment of canine urothelial carcinoma (UC) of the bladder is a challenge. More than 90% of the cases invade the muscular layer, more than 50% develop on bladder sites with a difficult surgical approach and often requiring radical surgical procedures. This study aims to evaluate the safety and feasibility of electrochemotherapy (ECT) with intravenous bleomycin (BLM) as a local therapy for bladder UC. This prospective study included 21 dogs with spontaneous bladder UC. Regional/distant metastases and neoplastic infiltration of the serosa was considered the main exclusion criteria. We had no deaths during ECT or in the immediate postoperative period, and no suture dehiscence. Most dogs (19/21) developed mild adverse effects, whereas two dogs developed ureteral stenosis. Complete response (CR) was achieved in 62% of the cases (13/21), while partial response (PR) was achieved in 24% (5/21). The median survival and disease-free survival times were 284 and 270 days, respectively. Overall survival was significantly better in the dogs who achieved a CR. In conclusion, ECT was well-tolerated in dogs with UC, demonstrating its safety and feasibility. These data pave the way for new studies aimed at evaluating the effectiveness of ECT in canine bladder UC as a translational model for human disease.

A Systematic Review of Canine Cystectomy: Indications, Techniques, and Outcomes

This review provides a summary of the literature encompassing partial and total cystectomy procedures in dogs and subsequent conclusions that can be drawn. Surgical excision as a component of treatment for lower urinary tract neoplasia in dogs may enhance survival time and result in acceptable quality of life, though risk for surgical complications is substantial, particularly following total cystectomy procedures. However, for dogs with urothelial carcinoma, cystectomy is generally not considered curative and disease progression is common. Appropriate case selection and thorough preoperative discussion with owners regarding potential risks and benefits of cystectomy are imperative for successful outcomes.

Cross-species oncogenomics offers insight into human muscle-invasive bladder cancer

BACKGROUND

In humans, muscle-invasive bladder cancer (MIBC) is highly aggressive and associated with a poor prognosis. With a high mutation load and large number of altered genes, strategies to delineate key driver events are necessary. Dogs and cats develop urothelial carcinoma (UC) with histological and clinical similarities to human MIBC. Cattle that graze on bracken fern also develop UC, associated with exposure to the carcinogen ptaquiloside. These species may represent relevant animal models of spontaneous and carcinogen-induced UC that can provide insight into human MIBC.

RESULTS

Whole-exome sequencing of domestic canine (n = 87) and feline (n = 23) UC, and comparative analysis with human MIBC reveals a lower mutation rate in animal cases and the absence of APOBEC mutational signatures. A convergence of driver genes (ARID1A, KDM6A, TP53, FAT1, and NRAS) is discovered, along with common focally amplified and deleted genes involved in regulation of the cell cycle and chromatin remodelling. We identify mismatch repair deficiency in a subset of canine and feline UCs with biallelic inactivation of MSH2. Bovine UC (n = 8) is distinctly different; we identify novel mutational signatures which are recapitulated in vitro in human urinary bladder UC cells treated with bracken fern extracts or purified ptaquiloside.

CONCLUSION

Canine and feline urinary bladder UC represent relevant models of MIBC in humans, and cross-species analysis can identify evolutionarily conserved driver genes. We characterize mutational signatures in bovine UC associated with bracken fern and ptaquiloside exposure, a human-linked cancer exposure. Our work demonstrates the relevance of cross-species comparative analysis in understanding both human and animal UC.

Meloxicam in Combination with Mitoxantrone or Vinblastine as First-Line Treatment for Non-Resectable Urothelial Cell Carcinoma in Dogs

Cyclooxygenase (COX) inhibitors have been demonstrated to have antitumour activity in canine urothelial cell carcinoma (UCC), given as a sole treatment or in combination with chemotherapy. The purpose of this retrospective multi-institutional study was to assess the efficacy of meloxicam in combination with mitoxantrone or vinblastine as a first-line treatment for non-resectable canine UCC. Gastrointestinal adverse effects (AEs) of these treatment combinations were also assessed. A total of 28 dogs met the inclusion criteria, 21/28 dogs received mitoxantrone and meloxicam, and 7/28 received vinblastine and meloxicam. Tumour response (TR) and AE were evaluated according to Veterinary Co-Operative Oncology Group (VCOG) criteria. The endpoint of the study was the time to tumour progression (TTP). The mitoxantrone-group induced 24% partial response and 62% stable disease, while the vinblastine-group induced 14% and 86%, respectively. Median TTP was 84 days (mitoxantrone and meloxicam, 70 days; and vinblastine and meloxicam, 178 days). The presence of metastatic disease significantly decreased TTP (p = 0.007). Gastrointestinal AEs were reported in 21.4% of the patients, with the most common being VCOG grade 1-2 diarrhoea. Meloxicam is a well-tolerated NSAID when combined with mitoxantrone or vinblastine as first-line treatment for non-resectable canine UCC.

Vaccination against Extracellular Vimentin for Treatment of Urothelial Cancer of the Bladder in Client-Owned Dogs

It was recently shown that targeting extracellular vimentin (eVim) is safe and effective in preclinical models. Here, we report the safety and efficacy in client-owned dogs with spontaneous bladder cancer of CVx1, an iBoost technology-based vaccine targeting eVim in combination with COX-2 inhibition. This was a single-arm prospective phase 1/2 study with CVx1 in 20 client-owned dogs with spontaneous UC which involved four subcutaneous vaccinations with CVx1 at 2-week intervals for induction of antibody titers, followed by maintenance vaccinations at 2-month intervals. Additionally, daily cyclooxygenase (COX)-2 inhibition with meloxicam was given. The response was assessed by antibody titers, physical condition, abdominal ultrasound and thorax X-ray. The primary endpoints were the development of antibody titers, as well as overall survival compared to a historical control group receiving carboplatin and COX-2 inhibition with piroxicam. Kaplan-Meier survival analysis was performed. All dogs developed antibodies against eVim. Titers were adequately maintained for the duration of this study. A median overall survival of 374 days was observed, which was 196 days for the historical control group (p < 0.01). Short-term grade 1-2 toxicity at the injection site and some related systemic symptoms peri-vaccination were observed. No toxicity was observed related to the induced antibody response. A limitation of this study is the single-arm prospective setting. CVx1 plus meloxicam consistently induced efficient antibody titers, was well tolerated and showed prolonged survival. The results obtained merit further development for human clinical care.

A Retrospective Clinico-Pathologic Study of 35 Dogs with Urethral Transitional Cell Carcinoma Undergoing Treatment

Chemotherapy and cyclooxygenase inhibitors (COXi) are primary treatments for canine urethral transitional cell carcinoma (uTCC), a tumor known for its aggressiveness and poor prognosis. This retrospective study aimed to evaluate the clinico-pathological characteristics, treatment modalities, and prognostic factors of 35 dogs with confirmed uTCC that received chemotherapy and COXi. Upon admission, urethral obstruction (UO) and urinary tract infection (UTI) were observed in seven (20%) dogs each. Gemcitabine (n = 20; 57.1%) and vinblastine (n = 10; 28.6%) were commonly used as first-line therapies, with four dogs also receiving radiation therapy. Based on RECIST, one (2.9%) dog achieved complete remission, nine (25.7%) partial remission, 20 (57.14%) showed stable disease, and five (14.3%) progressed. Among dogs with UO, six (85.7%) showed resolution or improvement after the first chemotherapy dose. The median time to local progression was 171 days (range: 107-235), and the median survival time was 333 days (range: 158-508). Dogs with UO upon admission had a higher risk of local progression, while both UO and UTI were associated with an increased risk of overall disease progression and tumor-related death. Additionally, gemcitabine significantly improved metastatic control. This study identified UO and UTI as negative prognostic factors, highlighting the importance of a multimodal approach in managing uTCC.

Inhibitory Potential of Resveratrol in Cancer Metastasis: From Biology to Therapy

Cancer metastasis is a significant challenge in cancer treatment, and most existing drugs are designed to inhibit tumor growth but are often ineffective in treating metastatic cancer, which is the leading cause of cancer-related deaths. Resveratrol, a polyphenol found in grapes, berries, and peanuts, has shown potential in preclinical studies as an anticancer agent to suppress metastasis. However, despite positive results in preclinical studies, little progress has been made in clinical trials. To develop resveratrol as an effective anticancer agent, it is crucial to understand its cellular processes and signaling pathways in tumor metastasis. This review article evaluates the current state and future development strategies of resveratrol to enhance its potency against cancer metastasis within its therapeutic dose. In addition, we critically evaluate the animal models used in preclinical studies for cancer metastasis and discuss novel techniques to accelerate the translation of resveratrol from bench to bedside. The appropriate selection of animal models is vital in determining whether resveratrol can be further developed as an antimetastatic drug in cancer therapy.

Potential Promises and Perils of Human Biological Treatments for Immunotherapy in Veterinary Oncology

The emergence of immunotherapy for the treatment of human cancers has heralded a new era in oncology, one that is making its way into the veterinary clinic. As the immune system of many animal species commonly seen by veterinarians is similar to humans, there is great hope for the translation of human therapies into veterinary oncology. The simplest approach for veterinarians would be to adopt existing reagents that have been developed for human medicine, due to the potential of reduced cost and the time it takes to develop a new drug. However, this strategy may not always prove to be effective and safe with regard to certain drug platforms. Here, we review current therapeutic strategies that could exploit human reagents in veterinary medicine and also those therapies which may prove detrimental when human-specific biological molecules are used in veterinary oncology. In keeping with a One Health framework, we also discuss the potential use of single-domain antibodies (sdAbs) derived from camelid species (also known as Nanobodies™) for therapies targeting multiple veterinary animal patients without the need for species-specific reformulation. Such reagents would not only benefit the health of our veterinary species but could also guide human medicine by studying the effects of outbred animals that develop spontaneous tumors, a more relevant model of human diseases compared to traditional laboratory rodent models.

Development of an Anti-canine PD-L1 Antibody and Caninized PD-L1 Mouse Model as Translational Research Tools for the Study of Immunotherapy in Humans

Immune checkpoint blockade therapy, one of the most promising cancer immunotherapies, has shown remarkable clinical impact in multiple cancer types. Despite the recent success of immune checkpoint blockade therapy, however, the response rates in patients with cancer are limited (∼20%-40%). To improve the success of immune checkpoint blockade therapy, relevant preclinical animal models are essential for the development and testing of multiple combination approaches and strategies. Companion dogs naturally develop several types of cancer that in many respects resemble clinical cancer in human patients. Therefore, the canine studies of immuno-oncology drugs can generate knowledge that informs and prioritizes new immuno-oncology therapy in humans. The challenge has been, however, that immunotherapeutic antibodies targeting canine immune checkpoint molecules such as canine PD-L1 (cPD-L1) have not been commercially available. Here, we developed a new cPD-L1 antibody as an immuno-oncology drug and characterized its functional and biological properties in multiple assays. We also evaluated the therapeutic efficacy of cPD-L1 antibodies in our unique caninized PD-L1 mice. Together, these in vitro and in vivo data, which include an initial safety profile in laboratory dogs, support development of this cPD-L1 antibody as an immune checkpoint inhibitor for studies in dogs with naturally occurring cancer for translational research. Our new therapeutic antibody and caninized PD-L1 mouse model will be essential translational research tools in raising the success rate of immunotherapy in both dogs and humans.

Significance

Our cPD-L1 antibody and unique caninized mouse model will be critical research tools to improve the efficacy of immune checkpoint blockade therapy in both dogs and humans. Furthermore, these tools will open new perspectives for immunotherapy applications in cancer as well as other autoimmune diseases that could benefit a diverse and broader patient population.

The impact of urine collection method on canine urinary microbiota detection: a cross-sectional study

BACKGROUND

The urinary tract harbors unique microbial communities that play important roles in urogenital health and disease. Dogs naturally suffer from several of the same urological disorders as humans (e.g., urinary tract infections, neoplasia, urolithiasis) and represent a valuable translational model for studying the role of urinary microbiota in various disease states. Urine collection technique represents a critical component of urinary microbiota research study design. However, the impact of collection method on the characterization of the canine urinary microbiota remains unknown. Therefore, the objective of this study was to determine whether urine collection technique alters the microbial populations detected in canine urine samples. Urine was collected from asymptomatic dogs by both cystocentesis and midstream voiding. Microbial DNA was isolated from each sample and submitted for amplicon sequencing of the V4 region of the bacterial 16 S rRNA gene, followed by analyses to compare microbial diversity and composition between urine collection techniques.

RESULTS

Samples collected via midstream voiding exhibited significantly higher sequence read counts (P = .036) and observed richness (P = .0024) than cystocentesis urine. Bray Curtis and Unweighted UniFrac measures of beta diversity showed distinct differences in microbial composition by collection method (P = .0050, R2 = 0.06 and P = .010, R2 = 0.07, respectively). Seven taxa were identified as differentially abundant between groups. Pasteurellaceae, Haemophilus, Friedmanniella, two variants of Streptococcus, and Fusobacterium were over-represented in voided urine, while a greater abundance of Burkholderia-Caballeronia-Paraburkholderia characterized cystocentesis samples. Analyses were performed at five thresholds for minimum sequence depth and using three data normalization strategies to validate results; patterns of alpha and beta diversity remained consistent regardless of minimum read count requirements or normalization method.

CONCLUSION

Microbial composition differs in canine urine samples collected via cystocentesis as compared to those collected via midstream voiding. Future researchers should select a single urine collection method based on the biological question of interest when designing canine urinary microbiota studies. Additionally, the authors suggest caution when interpreting results across studies that did not utilize identical urine collection methods.

Comparative oncology: overcoming human cancer through companion animal studies

Comparative oncology is a field of study that has been recently adopted for studying cancer and developing cancer therapies. Companion animals such as dogs can be used to evaluate novel biomarkers or anticancer targets before clinical translation. Thus, the value of canine models is increasing, and numerous studies have been conducted to analyze similarities and differences between many types of spontaneously occurring cancers in canines and humans. A growing number of canine cancer models as well as research-grade reagents for these models are becoming available, leading to substantial growth in comparative oncology research spanning from basic science to clinical trials. In this review, we summarize comparative oncology studies that have been conducted on the molecular landscape of various canine cancers and highlight the importance of the integration of comparative biology into cancer research.

Whole exome sequencing analysis of canine urothelial carcinomas without BRAF V595E mutation: Short in-frame deletions in BRAF and MAP2K1 suggest alternative mechanisms for MAPK pathway disruption

Molecular profiling studies have shown that 85% of canine urothelial carcinomas (UC) harbor an activating BRAF V595E mutation, which is orthologous to the V600E variant found in several human cancer subtypes. In dogs, this mutation provides both a powerful diagnostic marker and a potential therapeutic target; however, due to their relative infrequency, the remaining 15% of cases remain understudied at the molecular level. We performed whole exome sequencing analysis of 28 canine urine sediments exhibiting the characteristic DNA copy number signatures of canine UC, in which the BRAF V595E mutation was undetected (UDV595E specimens). Among these we identified 13 specimens (46%) harboring short in-frame deletions within either BRAF exon 12 (7/28 cases) or MAP2K1 exons 2 or 3 (6/28 cases). Orthologous variants occur in several human cancer subtypes and confer structural changes to the protein product that are predictive of response to different classes of small molecule MAPK pathway inhibitors. DNA damage response and repair genes, and chromatin modifiers were also recurrently mutated in UDV595E specimens, as were genes that are positive predictors of immunotherapy response in human cancers. Our findings suggest that short in-frame deletions within BRAF exon 12 and MAP2K1 exons 2 and 3 in UDV595E cases are alternative MAPK-pathway activating events that may have significant therapeutic implications for selecting first-line treatment for canine UC. We developed a simple, cost-effective capillary electrophoresis genotyping assay for detection of these deletions in parallel with the BRAF V595E mutation. The identification of these deletion events in dogs offers a compelling cross-species platform in which to study the relationship between somatic alteration, protein conformation, and therapeutic sensitivity.

Immunohistochemical analysis of expression of VEGFR2, KIT, PDGFR-β, and CDK4 in canine urothelial carcinoma

Urothelial carcinomas (UCs), also known as transitional cell carcinomas, are the most common canine urinary tract neoplasms. Tyrosine kinases (TKs) are enzymes that tightly regulate cell growth and differentiation through phosphorylation. Receptor TK (RTK) inhibitors are currently used to treat UCs. Toceranib phosphate (Palladia; Pfizer) is an RTK inhibitor that blocks the activity of vascular endothelial growth factor receptor 2 (VEGFR2), platelet-derived growth factor receptor-alpha and -beta (PDGFR-α, -β), FMS-like tyrosine kinase 3, stem cell factor receptor (KIT, kinase inhibitor targeting), and colony stimulating factor receptor. To better understand UCs and validate treatment targets, we performed immunohistochemical staining for RTKs, as well as a novel target, cyclin-dependent kinase 4 (CDK4, a central regulator of the mammalian cell cycle), on formalin-fixed, paraffin-embedded tissues from bladder biopsies from 17 dogs with UCs, 17 dogs with cystitis (diseased controls), and 8 normal dogs (negative controls). Although immunohistochemical scores could not be extrapolated to prognostic value, response to treatment, and outcome of patients with UC, we demonstrated expression of PDGFR-β and VEGFR2 in UCs; all UC samples staining positively for VEGFR2. Minimal positive staining for KIT was noted in the tumor samples. CDK4 staining intensity was significantly weaker in UCs compared with normal and cystitis bladder samples. The intense staining of VEGFR2 in UC cells suggested that VEGFR2 may be of prognostic and/or therapeutic value in dogs with UC. Overexpression of VEGFR2 in UC cells validates this receptor as a treatment target in UC.

Anti-cancer activity of Chaga mushroom (Inonotus obliquus) against dog bladder cancer organoids

Despite its disadvantages, chemotherapy is still commonly used for the treatment of bladder cancer (BC). Developing natural supplements that can target cancer stem cells (CSCs) which cause drug resistance and distant metastasis is necessary. Chaga mushrooms are popular to have several health-promoting and anti-cancer potentials. Organoid culture can recapitulate tumor heterogeneity, epithelial environment, and genetic and molecular imprints of the original tissues. In the previous study, we generated dog bladder cancer organoids (DBCO) as a novel experimental model of muscle-invasive BCO. Therefore, the present study aimed to examine the anti-tumor potentials of Chaga mushroom extract (Chaga) against DBCO. Four strains of DBCO were used in the present study. Treatment with Chaga inhibited the cell viability of DBCO in a concentration-dependent way. Treatment of DBCO with Chaga has significantly arrested its cell cycle and induced apoptosis. Expression of bladder CSC markers, CD44, C-MYC, SOX2, and YAP1, declined in the Chaga-treated DBCO. Also, Chaga inhibited the phosphorylation of ERK in DBCO. Expression of downstream signals of ERK, C-MYC, and Cyclins (Cyclin-A2, Cyclin-D1, Cyclin-E1, and CDK4) was also inhibited by Chaga in DBCO. Interestingly, the combinational treatment of DBCO with Chaga and anti-cancer drugs, vinblastine, mitoxantrone, or carboplatin, showed a potentiating activity. In vivo, Chaga administration decreased tumor growth and weight of DBCO-derived xenograft in mice with the induction of necrotic lesions. In conclusion, Chaga diminished the cell viability of DBCO by inhibiting proliferation-related signals and stemness conditions as well as by arresting the cell cycle. Collectively, these data suggest the value of Chaga as a promising natural supplement that could potentiate the effect of adjuvant chemotherapy, lower its adverse effects, and thus, limit the recurrence and metastasis of BC.

Establishment and characterization of urothelial carcinoma cell lines with and without BRAF mutation (V595E) in dogs

Each 5 urothelial carcinoma (UC) cell lines with and without the v-Raf murine sarcoma virus oncogene homolog B (BRAF) gene mutation (V595E) were established and examined V595E-related tumorigenic characteristics in dogs. No typical morphological features were observed in cloned cells with and without V595E. The cell proliferation of both cloned cells showed logarithmic growth curve and those doubling time were 24.9 ± 4.1 h in V595E ( +) and 29.3 ± 11.3 h in V595E ( -). On the growth curve of xenotransplanted tumor in severe combined immunodeficiency mice, 3 out of 5 V595E ( +) and 2 out of 5 V595E ( -) cloned cells revealed gradually and remarkably increasing curve, indicating clearly tumorigenicity. The xenotransplanted tumors with V595E ( +) showed typical features of UC, such as solid proliferation of pleomorphic tumor cells, formation of papillary structure, and glandular structure. Additionally, various vascular formation was observed, probably indicating an advanced growth phase of UC. In mitogen-activated protein kinase (MAPK) signaling pathway, cytoplasmic phosphorylated-BRAF (pBRAF) and cytoplasmic and nuclear phosphorylated-ERK1/2 (pERK1/2) were detected in all 4 tumors with V595E ( +), whereas only cytoplasmic and nuclear pERK1/2 was detected in tumors with V595E ( -). Since V595E can directly activate MAPK signaling pathway, coincidence of V595E with pBRAF (phosphor Thr598/Ser601) indicates acquired resistance to BRAF inhibitors. These established UC cell lines, especially V595E ( +) cell lines, are useful tool for understanding pathophysiological states and controlling therapeutic manners of UC in dogs.

Tissue S100/calgranulin expression and blood neutrophil-to-lymphocyte ratio (NLR) in dogs with lower urinary tract urothelial carcinoma

BACKGROUND

Urothelial carcinoma (UC) is the most common neoplasm of the canine lower urinary tract, affecting approximately 2% of dogs. Elderly female patients of certain breeds are predisposed, and clinical signs of UC can easily be confused with urinary tract infection or urolithiasis. Diagnosis and treatment are challenging given the lack of disease-specific markers and treatments. The S100A8/A9 complex and S100A12 protein are Ca²⁺-binding proteins expressed by cells of the innate immune system and have shown promise as urinary screening markers for UC. The neutrophil-to-lymphocyte ratio (NLR) can also aid in distinguishing certain neoplastic from inflammatory conditions. Our study aimed to evaluate the tissue expression of S100/calgranulins and the blood NLR in dogs with UC. Urinary bladder and/or urethral tissue samples from dogs with UC (n = 10), non-neoplastic inflammatory lesions (NNUTD; n = 6), and no histologic changes (n = 11) were evaluated using immunohistochemistry. Blood NLRs were analyzed in dogs with UC (n = 22) or NNUTD (n = 26).

RESULTS

Tissue S100A12-positive cell counts were significantly higher in dogs with lower urinary tract disease than healthy controls (P = 0.0267 for UC, P = 0.0049 for NNUTD), with no significant difference between UC and NNUTD patients. Tissue S100A8/A9-positivity appeared to be higher with NNUTD than UC, but this difference did not reach statistical significance. The S100A8/A9⁺-to-S100A12⁺ ratio was significantly decreased in neoplastic and inflamed lower urinary tract tissue compared to histologically normal specimens (P = 0.0062 for UC, P = 0.0030 for NNUTD). NLRs were significantly higher in dogs with UC than in dogs with NNUTD, and a cut-off NLR of ≤ 2.83 distinguished UC from NNUTD with 41% sensitivity and 100% specificity. Higher NLRs were also associated with a poor overall survival time (P = 0.0417).

CONCLUSIONS

These results confirm that the S100/calgranulins play a role in the immune response to inflammatory and neoplastic lower urinary tract diseases in dogs, but the tissue expression of these proteins appears to differ from their concentrations reported in urine samples. Further investigations of the S100/calgranulin pathways in UC and their potential as diagnostic or prognostic tools and potential therapeutic targets are warranted. The NLR as a routinely available marker might be a useful surrogate to distinguish UC from inflammatory conditions.

Identification of a naturally-occurring canine model for early detection and intervention research in high grade urothelial carcinoma

Background

Early detection and intervention research is expected to improve the outcomes for patients with high grade muscle invasive urothelial carcinoma (InvUC). With limited patients in suitable high-risk study cohorts, relevant animal model research is critical. Experimental animal models often fail to adequately represent human cancer. The purpose of this study was to determine the suitability of dogs with high breed-associated risk for naturally-occurring InvUC to serve as relevant models for early detection and intervention research. The feasibility of screening and early intervention, and similarities and differences between canine and human tumors, and early and later canine tumors were determined.

Methods

STs (n=120) ≥ 6 years old with no outward evidence of urinary disease were screened at 6-month intervals for 3 years with physical exam, ultrasonography, and urinalysis with sediment exam. Cystoscopic biopsy was performed in dogs with positive screening tests. The pathological, clinical, and molecular characteristics of the "early" cancer detected by screening were determined. Transcriptomic signatures were compared between the early tumors and published findings in human InvUC, and to more advanced "later" canine tumors from STs who had the typical presentation of hematuria and urinary dysfunction. An early intervention trial of an oral cyclooxygenase inhibitor, deracoxib, was conducted in dogs with cancer detected through screening.

Results

Biopsy-confirmed bladder cancer was detected in 32 (27%) of 120 STs including InvUC (n=29, three starting as dysplasia), grade 1 noninvasive cancer (n=2), and carcinoma in situ (n=1). Transcriptomic signatures including druggable targets such as EGFR and the PI3K-AKT-mTOR pathway, were very similar between canine and human InvUC, especially within luminal and basal molecular subtypes. Marked transcriptomic differences were noted between early and later canine tumors, particularly within luminal subtype tumors. The deracoxib remission rate (42% CR+PR) compared very favorably to that with single-agent cyclooxygenase inhibitors in more advanced canine InvUC (17-25%), supporting the value of early intervention.

Conclusions

The study defined a novel naturally-occurring animal model to complement experimental models for early detection and intervention research in InvUC. Research incorporating the canine model is expected to lead to improved outcomes for humans, as well as pet dogs, facing bladder cancer.

Caveolin-1, GATA-3, and Ki67 expressions and their correlation with pathological findings in canine bladder urothelial carcinoma

The bladder urothelial carcinoma (UC) represents ~2% of malignant neoplasms in dogs and is a therapeutic challenge in veterinary medicine. Although it is considered the most common bladder cancer in dogs, few previous studies have investigated different markers that correlate with clinical and pathological parameters. Therefore, this study aimed to evaluate Caveolin-1, GATA-3, and Ki67 immunostaining in canine UC samples to evaluate their correlations with histopathological variables. Thirty tumor samples were obtained, and Caveolin-1, GATA-3, and Ki67 expression was assessed by immunohistochemistry and associated with pathological factors by univariate and multivariate analyses. Among the histopathological findings, lymphatic invasion was identified in 53.33% of the tumors, and the mean mitotic count (MC) was 31.82 ± 26.26. Caveolin-1 showed mild-to-high cytoplasmic expression in neoplastic cells, whereas GATA-3 showed mild-to-high nuclear expression. The Ki67 expression revealed a mean of 24.14 ± 16.88% positive cells. In the univariate analysis, no association was found between each marker and the pathological findings. On the other hand, in multivariate analysis, we identified a positive correlation between GATA-3 and MC and a negative correlation between Caveolin-1 and MC. Moreover, lymphatic invasion was positively correlated with histological type and grade, and negatively correlated with MC. In addition, the histological type was positively correlated with the histological grade. Overall, our results indicate that Caveolin-1 and GATA-3 expression could be promising markers for bladder UC aggressiveness.

Targeted elastin-like polypeptide fusion protein for near-infrared imaging of human and canine urothelial carcinoma

Cystoscopic visualization of bladder cancer is an essential method for initial bladder cancer detection and diagnosis, transurethral resection, and monitoring for recurrence. We sought to develop a new intravesical imaging agent that is more specific and sensitive using a polypeptide based NIR (near-infrared) probe designed to detect cells bearing epidermal growth factor receptors (EGFR) that are overexpressed in 80% of urothelial carcinoma (UC) cases. The NIR imaging agent consisted of an elastin like polypeptide (ELP) fused with epidermal growth factor (EGF) and conjugated to Cy5.5 to give Cy5.5-N24-EGF as a NIR contrast agent. In addition to evaluation in human cells and tissues, the agent was tested in canine cell lines and tissue samples with naturally occurring invasive UC. Flow cytometry and confocal microscopy were used to test cell-associated fluorescence of the probe in T24 human UC cells, and in K9TCC-SH (high EGFR expression) and K9TCC-Original (low EGF expression) canine cell lines. The probe specifically engages these cells through EGFR within 15 min of incubation and reached saturation within a clinically relevant 1 h timeframe. Furthermore, ex vivo studies with resected canine and human bladder tissues showed minimal signal from normal adjacent tissue and significant NIR fluorescence labeling of tumor tissue, in good agreement with our in vitro findings. Differential expression of EGFR ex vivo was revealed by our probe and confirmed by anti-EGFR immunohistochemical staining. Taken together, our data suggests Cy5.5-ELP-EGF is a NIR probe with improved sensitivity and selectivity towards BC that shows excellent potential for clinical translation.

Irreversible Electroporation Balloon Therapy for Palliative Treatment of Obstructive Urethral Transitional Cell Carcinoma in Dogs

Progression of transitional cell carcinoma (TCC) in dogs often leads to urinary obstruction. This observational pilot study aimed to evaluate the safety and efficacy of irreversible electroporation (IRE) balloon therapy for the palliative treatment of TCC with partial urethral obstruction. Three client-owned dogs diagnosed with TCC causing partial urethral obstruction were enrolled. After ultrasonographic and cystoscopic examination, IRE pulse protocols were delivered through a balloon catheter device inflated within the urethral lumen. After the procedure, the patients were kept overnight for monitoring and a recheck was planned 28 days later. No complication was observed during the procedure and postprocedural monitoring. After 28 days, one dog had a complete normalization of the urine stream, one dog had stable stranguria, and one dog was presented with a urethral obstruction secondary to progression of the TCC. On recheck ultrasound, one dog had a 38% diminution of the urethral mass diameter whereas the other two dogs had a mass stable in size. IRE balloon therapy seems to be a feasible and apparently safe minimally invasive novel therapy for the palliative treatment of TCC causing urethral obstruction. Further studies are needed to better characterize the safety, efficacy, and outcome of this therapy.

Establishment of a direct 2.5D organoid culture model using companion animal cancer tissues

Like humans, cancer affects companion animals with similar genetic risks and incident rates. To improve treatment strategies for pet cancers, new research models are necessary. Patient-derived 3D organoid culture models are valuable and ensure the development of new effective therapies. In the previous study, we established a 3D organoid-derived 2.5D organoid culture model that recapitulated some characteristics of their parental 3D organoids. In the present study, we aimed to generate a 2.5D organoid culture model directly from cancer-diseased dogs and cats using special 2.5D media. The primary cultured cells in 2.5D media (direct 2.5D organoids) showed better attachment, growth, marker expression, and faster proliferation speed than those cultured in normal Dulbecco's Modified Eagle Medium media. The direct 2.5D organoids showed expression of each specific marker to their original cancer tissues and exhibited tumorigenesis in vivo. Moreover, the direct 2.5D organoids exhibited concentration-dependent responses to anti-cancer drugs, and different sensitivity profiles were shown among the strains. Our data suggest that the direct 2.5D organoid culture model might become a useful tool beyond 2D cell lines to study cancer biology in companion animals and could provide new platforms for screening the anti-cancer drugs.

The miRNome of canine invasive urothelial carcinoma

Urothelial carcinoma (UC) comprises up to 2% of all naturally occurring neoplasia in dogs and can be challenging to diagnose. MicroRNAs (miRNAs) have been reported to be dysregulated in numerous diseases, including neoplasia. MiRNA expression has been evaluated in human UC, but there is limited information regarding the miRNA transcriptome of UC in dogs. Our study aimed to evaluate differential miRNA expression in bladder tissue collected from normal canine urothelium and canine invasive UC (iUC) to elucidate the dysregulated pathways in canine UC. Next-Generation RNA sequencing (RNA-Seq) was performed for dogs with UC (n = 29) and normal canine urothelium (n = 4). Raw RNA data were subjected to normalization, and pairwise comparison was performed using EdgeR with Benjamini-Hochberg FDR multiple testing correction (p < 0.05; >2-fold change) comparing tissue samples of normal urothelium to canine iUC samples. Principal component analysis and hierarchical cluster analysis were performed. MiRNA of FFPE tissue samples of separate iUC (n = 5) and normal urothelium (n = 5) were used to evaluate five miRNAs using RT-qPCR. Pathway analysis was performed utilizing miRWalk, STRING database, and Metascape utilizing KEGG pathways and GO terms databases. Twenty-eight miRNAs were differentially expressed (DE) by RNA-Seq. RT-qPCR confirmed that four miRNAs are significantly downregulated in UC compared to healthy urothelial samples (miR-105a, miR-143, miR-181a, and miR-214). Principal component analysis and hierarchical cluster analysis showed separation between miRNAs in iUC and the control group. The DE miRNAs are most often associated with gene silencing by miRNA, miRNAs in cancer, and miRNAs involved in DNA damage responses. Proteins involved include HRAS, KRAS, ARAF, RAF1, MAPK1, MAP2K1, MAPK3, FGFR3, EGFR, HBEGF, RASSF1, E2F2, E2F3, ERBB2, SRC, MMP1, and UP3KA. The differential expression of miRNAs in canine iUC compared to normal canine urothelial tissue indicates that these markers should be further evaluated for their potential role as diagnostic and therapeutic targets.

The Italian Network of Laboratories for Veterinary Oncology (NILOV) 2.0: Improving Knowledge on Canine Tumours

Simple Summary

Advances in cancer research are crucial, and pet oncology can improve the knowledge in several ways. Dogs are not only models of specific naturally occurring tumours but can also be sentinels of environmental exposures to carcinogenic substances, as they share the same environment with their owners. The purpose of this work was to describe the data collected by The Italian Network of Laboratories for Veterinary Oncology in the first 9 years of activity (2013–2021) and to evaluate their potential epidemiological significance. Frequencies of tumour sites in dogs were described, analysed and compared, considering several risk factors (breed, sex, period and region of residence). These observations allowed us to highlight differences not only in the site of occurrence of some tumours but also to formulate hypotheses on the potential role of some risk factors, e.g., neutering/spaying or geographical location. In our opinion, the results of this study confirm the importance of initiating and consolidating animal cancer registration initiatives that would facilitate the possibility of conducting multicentric collaborative studies to deepen the knowledge of the epidemiology of tumours in dogs and, from a comparative perspective, in humans.

Abstract

Advances in tumour research are crucial, and comparative oncology can improve the knowledge in several ways. Dogs are not only models of specific naturally occurring tumours but can also be sentinels of environmental exposures to carcinogens, as they share the same environment with their owners. The purpose of this work was to describe the data collected by The Italian Network of Laboratories for Veterinary Oncology in the first 9 years of activity (2013–2021) and to evaluate their potential epidemiological significance. Frequencies of tumour topographies and main morphologies in dogs were described, analysed and compared, calculating age-adjusted proportional morbidity ratios and considering several risk factors (breed, sex, period and region of residence). These observations allowed us to highlight differences not only in morphology and topography of some tumours but also to formulate hypotheses on the potential role of some risk factors, e.g., neutering/spaying or geographical location. In our opinion, the results of this case series confirm the importance of initiating and consolidating animal cancer registration initiatives that would facilitate the possibility of conducting multicentric collaborative studies to deepen the knowledge of the epidemiology of tumours in dogs from a comparative perspective.

Usefulness of squash preparation cytology in the diagnosis of canine urinary bladder carcinomas

BACKGROUND

Epithelial cells show varying degrees of cytologic atypia in dogs with nonmalignant lesions (NML) and carcinomas (ubC) of the bladder, making histopathologic examination necessary for a definitive diagnosis.

OBJECTIVES

This study aimed to investigate the diagnostic performance of squash preparation cytology and identify several cytomorphologic features of ubC to assist in diagnoses.

METHODS

Squash preparations were made and reviewed in dogs that underwent transurethral cystoscopy. The results were compared with histopathologic diagnoses. Two cytopathologists performed blinded assessments using a scoring system established for 11 cytologic features, including the presence of macronuclei, abnormal nucleoli, atypical mitoses, signet ring cells, multinucleated cells, nuclear molding, anisokaryosis, cytoplasmatic microvacuolization, cell arrangements, and neutrophil and lymphocyte infiltrations. Based on cytologic and histopathologic diagnoses, dogs were divided into ubC and NML groups. Associations between cytologic and histopathologic diagnoses were investigated, and agreement between the cytopathologists was calculated. Cytologic features were analyzed with multivariate logistic regression models. The performance of predictors in the final model was evaluated in terms of Sensitivity (Se), Specificity (Sp), accuracy, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio positive (LR+), and negative (LR-) values, and the diagnostic odds ratio (DOR).

RESULTS

Forty-four dogs diagnosed with ubC, and 17 with NML were included in the study. Cytologic and histopathologic diagnoses were significantly associated with each cytopathologist. There was an almost perfect agreement between cytopathologists (κ = 0.88). The absence of neutrophilic infiltration, the presence of multinucleated cells, and nuclear molding were associated with ubC; using a combination of these features in parallel testing resulted in Se = 0.98, Sp = 0.65, accuracy = 0.89, PPV = 0.88, NPV = 0.92, LR + =2.77, LR- = 0.04, and DOR = 7.7.

CONCLUSIONS

Squash preparation cytology could be a reliable technique to diagnose ubC in dogs. The best diagnostic combination was the absence of neutrophilic infiltration, multinucleated cells, and nuclear molding.

Advances and challenges of CAR T therapy and suitability of animal models (Review)

Chimeric antigen receptors (CARs) recently gained momentum in cancer treatment due to their ability to promote T-cell mediated responses to a specific tumor-associated antigen. CARs are part of the adoptive cell transfer (ACT) strategies that utilize patients' T lymphocytes, genetically engineered to kill cancer cells. However, despite the therapy's success against blood-related malignancies, treating solid tumors has not reached its fullest potential yet. The reasons include the complex suppressive tumor microenvironment, mutations on cancer cells' target receptors, lethal side-effects, restricted trafficking into the tumor, suboptimal persistence in vivo and the lack of animal models that faithfully resemble human tumor's immunological responses. Currently, rodent models are used to investigate the safety and efficacy of CAR therapies. However, these models are limited in representing the human disease faithfully, fail to predict the adverse treatment events and overestimate the efficacy of the therapy. On the other hand, spontaneously developed tumors in dogs are more suited in CAR research and their efficacy has been demonstrated in a number of diseases, including lymphoma, osteosarcoma and mammary tumors. The present review discusses the design and evolution of CARs, challenges of CAR in solid tumors, human and canine clinical trials and advantages of the canine model.

Establishment of an experimental model of normal dog bladder organoid using a three-dimensional culture method

Dog bladder cancer (BC) is mostly muscle-invasive (MI) with poor prognosis, and its pathogenesis is close to human MIBC. Three-dimensional (3D) organoid culture ensures novel knowledge on cancer diseases including BC. Recently, we have established dog BC organoids (BCO) using their urine samples. BCO recapitulated the epithelial structures, characteristics, and drug sensitivity of BC-diseased dogs. However, organoids from dog normal bladder epithelium are not established yet. Therefore, the present study aimed to establish dog normal bladder organoids (NBO) for further understanding the pathogenesis of dog BC and human MIBC. The established NBO underwent various analyzes including cell marker expressions, histopathological structures, cancer-related gene expression patterns, and drug sensitivity. NBO could be produced non-invasively with a continuous culturing and recapitulated the structures and characteristics of the dog's normal bladder mucosal tissues. Different drug sensitivities were observed in each NBO. The analysis of RNA sequencing revealed that several novel genes were changed in NBO compared with BCO. NBO showed a higher expression of p53 and E-cadherin, but a lower expression of MDM2 and Twist1 compared with BCO. These results suggest that NBO could be a promising experimental 3D model for studying the developmental mechanisms of dog BC and human MIBC.

Grading Systems for Canine Urothelial Carcinoma of the Bladder: A Comparative Overview

Simple Summary

Tumor histological grading systems are a tool widely used by human pathologists in oncology to support the assessment of tumor behavior and patient prognosis by clinical oncologists. In veterinary medicine, several tumor types already have a histological grading system used for these purposes, but some of these schemes lack reproducibility or correlation with clinical parameters, such as the correlation of the grade with survival time. This is the case for the grading systems proposed for canine bladder urothelial carcinoma. Over the years, some grading systems have been described for this type of tumor in dogs but without any routine use by pathologists and, consequently, without any application in clinical practice either. Based on this fact, the present study aimed to review the histological grading systems that exist in both human and veterinary medicine for bladder urothelial carcinoma, carrying out a critical analysis of their differences and thereby encouraging their real practical use and application in a relevant number of cases, prospectively. In this way, a histological grading system could be chosen or built from the existing ones and the knowledge about the behavior of this neoplasm in canine species could be improved, helping clinicians to establish a prognosis and personalized treatment for each patient with bladder urothelial carcinoma and also consider the predictive markers associated with treatment outcomes.

Abstract

The relationship between tumor morphology and clinical behavior is a key point in oncology. In this scenario, pathologists and clinicians play a pivotal role in the identification and testing of reliable grading systems based on standardized parameters to predict patient prognosis. Dogs with bladder urothelial carcinoma (BUC) were recently proposed as a “large animal” model for the study of human BUCs due to the similar morphology and metastasis locations. BUC grading systems are consolidated in human medicine, while in veterinary medicine, the BUC grading systems that have been proposed for canine tumors are not yet applied in routine diagnostics. These latter systems have been proposed, decade by decade, over the last thirty years, and the reason for their scarce application is mainly related to a lack of specific cutoff values and studies assessing their prognostic relevance. However, for any prognostic study, reliable grading is necessary. The aim of the present article was to give an overview of the BUC grading systems available in both human and veterinary pathology and provide an extensive description and a critical evaluation to support veterinary researchers in the choice of possible grading systems to apply in future studies on canine BUCs.

Validation of a Liquid Biopsy Protocol for Canine BRAFV595E Variant Detection in Dog Urine and Its Evaluation as a Diagnostic Test Complementary to Cytology

A significant proportion of canine urothelial carcinomas carry the driver valine to glutamic acid variation (V595E) in BRAF kinase. The detection of V595E may prove suitable to guide molecularly targeted therapies and support non-invasive diagnosis of the urogenital system by means of a liquid biopsy approach using urine. Three cohorts and a control group were included in this multi-step validation study which included setting up a digital PCR assay. This was followed by investigation of preanalytical factors and two alternative PCR techniques on a liquid biopsy protocol. Finally, a blind study using urine as diagnostic sample has been carried out to verify its suitability as diagnostic test to complement cytology. The digital PCR (dPCR) assay proved consistently specific, sensitive, and linear. Using the dPCR assay, the prevalence of V595E in 22 urothelial carcinomas was 90.9%. When compared with histopathology as gold standard in the blind-label cases, the diagnostic accuracy of using the canine BRAF (cBRAF) variation as a surrogate assay against the histologic diagnosis was 85.7% with 92.3% positive predictive value and 80.0% negative predictive value. In all the cases, in which both biopsy tissue and the associated urine were assayed, the findings matched completely. Finally, when combined with urine sediment cytology examination in blind-label cases with clinical suspicion of malignancy, the dPCR assay significantly improved the overall diagnostic accuracy. A liquid biopsy approach on urine using the digital PCR may be a valuable breakthrough in the diagnostic of urothelial carcinomas in dogs.

Extracellular vimentin mimics VEGF and is a target for anti-angiogenic immunotherapy

Anti-angiogenic cancer therapies possess immune-stimulatory properties by counteracting pro-angiogenic molecular mechanisms. We report that tumor endothelial cells ubiquitously overexpress and secrete the intermediate filament protein vimentin through type III unconventional secretion mechanisms. Extracellular vimentin is pro-angiogenic and functionally mimics VEGF action, while concomitantly acting as inhibitor of leukocyte-endothelial interactions. Antibody targeting of extracellular vimentin shows inhibition of angiogenesis in vitro and in vivo. Effective and safe inhibition of angiogenesis and tumor growth in several preclinical and clinical studies is demonstrated using a vaccination strategy against extracellular vimentin. Targeting vimentin induces a pro-inflammatory condition in the tumor, exemplified by induction of the endothelial adhesion molecule ICAM1, suppression of PD-L1, and altered immune cell profiles. Our findings show that extracellular vimentin contributes to immune suppression and functions as a vascular immune checkpoint molecule. Targeting of extracellular vimentin presents therefore an anti-angiogenic immunotherapy strategy against cancer.

The pro-tumorigenic effects of vimentin have been attributed to intracellular functions in tumour cells so far. Here, the authors show that tumour endothelial cells can secrete vimentin as a pro-angiogenic factor and that targeting of vimentin can be used as an immunotherapeutic strategy.

Canine models of human cancer: Bridging the gap to improve precision medicine

Dogs are remarkable, adaptable, and dependable creatures that have evolved alongside humans while contributing tremendously to our survival. Our canine companions share many similarities to human disease, particularly cancer. With the advancement of next-generation sequencing technology, we are beginning to unravel the complexity of cancer and the vast intra- and intertumoral heterogeneity that makes treatment difficult. Consequently, precision medicine has emerged as a therapeutic approach to improve patient survival by evaluating and classifying an individual tumor's molecular profile. Many canine and human cancers share striking similarities in terms of genotypic, phenotypic, clinical, and histological presentations. Dogs are superior to rodent models of cancer because they are a naturally heterogeneous population in which tumors occur spontaneously, are exposed to similar environmental conditions, and show more similarities in key modulators of tumorigenesis and clinical response, including the immune system, drug metabolism, and gut microbiome. In this chapter, we will explore various canine models of human cancers and emphasize the dog's critical role in advancing precision medicine and improving the survival of both man and man's best friend.

Sorafenib inhibits tumor cell growth and angiogenesis in canine transitional cell carcinoma

Canine transitional cell carcinoma (cTCC) is the most common naturally occurring bladder cancer and accounts for 1-2% of canine tumors. The prognosis is poor due to the high rate of invasiveness and metastasis at diagnosis. Sorafenib is a multi-kinase inhibitor that targets rapidly accelerated fibrosarcoma (RAF), vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, VEGFR-3, platelet-derived growth factor receptor-β (PDGFR-β), and KIT. In previous studies, a somatic mutation of B-rapidly accelerated fibrosarcoma (BRAF) and expressions of VEGFR-2 and PDGFR-β were observed in over 80% of patients with cTCC. Therefore, in this study, we investigated the anti-tumor effects of sorafenib on cTCC. Five cTCC cell lines were used in the in vitro experiments. All five cTCC cell lines expressed VEGFR-2 and PDGFR-β and sorafenib showed growth inhibitory effect on cTCC cell lines. Cell cycle arrest at the G0/G1 phase and subsequent apoptosis were observed following sorafenib treatment. In the in vivo experiments, cTCC (Sora) cells were subcutaneously injected into nude mice. Mice were orally administered with sorafenib (30 mg/kg daily) for 14 days. Sorafenib inhibited tumor growth compared to vehicle control. The necrotic area in the tumor tissues was increased in the sorafenib-treated group. Sorafenib also inhibited angiogenesis in the tumor microenvironment. Thus, sorafenib may be potential therapeutic agent for cTCC via its direct anti-tumor effect and inhibition of angiogenesis.