Naturally-Occurring Canine Invasive Urothelial Carcinoma: A Model for Emerging Therapies

Antitumor Effect of Curcumin, D6 Turmeric, and Hydrochloride Mitoxantrone on Canine and Human Urothelial Cancer Cells

Bladder urothelial carcinoma (UC) is an aggressive malignancy in both humans and dogs, with limited treatment options. Owing to their biological and environmental similarities with humans, dogs serve as a valuable model for UC research. Standard treatments, including surgery, chemotherapy, and anti-inflammatory agents, have shown limited efficacy. Curcumin, a bioactive compound derived from turmeric, has demonstrated anticancer properties, but its potential in canine UC remains poorly understood. In this study, we evaluated the effects of curcumin, D6 turmeric, and mitoxantrone hydrochloride on canine and human UC cell lines. Cell viability was assessed via the MTT assay, apoptosis via flow cytometry, and gene expression (β-catenin, β1-integrin, CDH1, MMP-2, MMP-9, and TIMP-2) via quantitative PCR. Migration capacity was analyzed using a Transwell assay. Curcumin and D6 turmeric reduced cell viability and migration, while mitoxantrone hydrochloride exhibited strong cytotoxicity, especially in canine cells. Curcumin also induced apoptosis and modulated genes involved in epithelial-mesenchymal transition and invasion. The interindividual differences in response suggest underlying genetic variability and highlight the need for personalized therapeutic approaches. These findings suggest that curcumin and D6 turmeric hold promise as complementary therapies for canine UC, justifying further in vivo investigations.

Identification of metastasis-associated protein 1 (MTA1) as a new molecular marker for canine urothelial carcinoma

Background

Although metastasis-associated protein 1 (MTA1) is known to play a role in cancer invasion and metastasis of various cancers, the clinical significance of its expression in canine urothelial carcinoma (UC) has not been explored. We sought to evaluate the expression of MTA1, cyclooxygenase 2 (COX2) and E-cadherin (E-cad) in association with clinicopathological parameters in clinical samples of canine UC.

Methods

We retrospectively analyzed UC tissues from 28 canine patients using immunohistochemistry for Ki67, CD31, MTA1, COX2, and E-cad staining. Statistical significance for marker staining intensities was evaluated by ANOVA or Student's t-test. The correlation between molecular markers in canine UC samples detected by IHC and clinicopathological features was calculated by the Wilcoxon (Mann-Whitney) and Kruskal-Wallis tests. Western blot analysis was performed for detection of EMT markers in canine cell lines.

Results

We show that MTA1 and COX2 are overexpressed in canine UC samples compared to normal canine bladder samples, whereas E-cad levels are higher in normal bladder. The results demonstrated that MTA1 expression correlated with aggressive clinicopathological features such as high tumor-grade, muscular/vascular invasion, and metastasis. The expression of MTA1 differed in tumors depending on their localization, with the highest being in the urethra adjoining the prostate. Unexpectedly, higher E-cad levels were detected in metastatic tumor cells compared to primary tumor cells.

Conclusion

These findings suggest that MTA1 may represent a key upstream effector tightly associated with COX2 and E-cad-mediated events in canine UC. Accordingly, MTA1 may be considered a feasible interceptive and therapeutic target for canine UC treatment.

Anticancer potentials of chaga and notoginseng against dog bladder cancer organoids

Muscle-invasive bladder cancer (MIBC) is a common form of BC in dogs. Adjuvant chemotherapy administration is commonly applied in MIBC cases, but patients sometimes experience treatment failure and recurrence. Therefore, supplements with anticancer properties, such as traditional Chinese medicines (TCMs), are required, and they have been widely used in Japanese human medicine and may be useful in veterinary medicine. Furthermore, organoid cultures can mimic the characteristics of their original tissues, such as self-renewal and organization. We previously established a novel experimental model for MIBC using a dog BC organoid (DBCO) culture. Herein, we examined the antiproliferative effects and mechanisms of 39 substances, consisting of TCMs, TCM supplements, and crude drug extracts, on DBCOs. Among the TCMs, D3 (also known as Shibe-ria), which is a mixture of chaga (Inonotus obliquus) and notoginseng (Panax notoginseng), significantly diminished the cell viability of DBCOs. The expression of BC stem cell markers, CD44 and SOX2, was reduced considerably in the D3-treated DBCOs. Among the components of D3, chaga exerted an antiproliferative effect on DBCO, whereas notoginseng did not. The administration of D3 also significantly reduced the volume of DBCO xenografted tumors in mice in vivo. Overall, D3 may have benefits as a natural anticancer supplement in veterinary medicine.

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.

Bringing the Genomic Revolution to Comparative Oncology: Human and Dog Cancers

Dogs are humanity's oldest friend, the first species we domesticated 20,000-40,000 years ago. In this unequaled collaboration, dogs have inadvertently but serendipitously been molded into a potent human cancer model. Unlike many common model species, dogs are raised in the same environment as humans and present with spontaneous tumors with human-like comorbidities, immunocompetency, and heterogeneity. In breast, bladder, blood, and several pediatric cancers, in-depth profiling of dog and human tumors has established the benefits of the dog model. In addition to this clinical and molecular similarity, veterinary studies indicate that domestic dogs have relatively high tumor incidence rates. As a result, there are a plethora of data for analysis, the statistical power of which is bolstered by substantial breed-specific variability. As such, dog tumors provide a unique opportunity to interrogate the molecular factors underpinning cancer and facilitate the modeling of new therapeutic targets. This review discusses the emerging field of comparative oncology, how it complements human and rodent cancer studies, and where challenges remain, given the rapid proliferation of genomic resources. Increasingly, it appears that human's best friend is becoming an irreplaceable component of oncology research.

Checkpoint Inhibitors in Dogs: Are We There Yet?

Immune checkpoint inhibitors (ICI) have revolutionised cancer treatment in people. Immune checkpoints are important regulators of the body's reaction to immunological stimuli. The most studied immune checkpoint molecules are programmed death (PD-1) with its ligand (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) with its ligands CD80 (B7-1) and CD86 (B7-2). Certain tumours can evade immunosurveillance by activating these immunological checkpoint targets. These proteins are often upregulated in cancer cells and tumour-infiltrating lymphocytes, allowing cancer cells to evade immune surveillance and promote tumour growth. By blocking inhibitory checkpoints, ICI can help restore the immune system to effectively fight cancer. Several studies have investigated the expression of these and other immune checkpoints in human cancers and have shown their potential as therapeutic targets. In recent years, there has been growing interest in studying the expression of immune checkpoints in dogs with cancer, and a few small clinical trials with ICI have already been performed on these species. Emerging studies in veterinary oncology are centred around developing and validating canine-targeted antibodies. Among ICIs, anti-PD-1 and anti-PD-L1 treatments stand out as the most promising, mirroring the success in human medicine over the past decade. Nevertheless, the efficacy of caninized antibodies remains suboptimal, especially for canine oral melanoma. To enhance the utilisation of ICIs, the identification of predictive biomarkers for treatment response and the thorough screening of individual tumours are crucial. Such endeavours hold promise for advancing personalised medicine within veterinary practice, thereby improving treatment outcomes. This article aims to review the current research literature about the expression of immune checkpoints in canine cancer and the current results of ICI treatment in dogs.

Oncopig bladder cancer cells recapitulate human bladder cancer treatment responses in vitro

Introduction

Bladder cancer is a common neoplasia of the urinary tract that holds the highest cost of lifelong treatment per patient, highlighting the need for a continuous search for new therapies for the disease. Current bladder cancer models are either imperfect in their ability to translate results to clinical practice (mouse models), or rare and not inducible (canine models). Swine models are an attractive alternative to model the disease due to their similarities with humans on several levels. The Oncopig Cancer Model has been shown to develop tumors that closely resemble human tumors. However, urothelial carcinoma has not yet been studied in this platform.

Methods

We aimed to develop novel Oncopig bladder cancer cell line (BCCL) and investigate whether these urothelial swine cells mimic human bladder cancer cell line (5637 and T24) treatment-responses to cisplatin, doxorubicin, and gemcitabine in vitro.

Results

Results demonstrated consistent treatment responses between Oncopig and human cells in most concentrations tested (p>0.05). Overall, Oncopig cells were more predictive of T24 than 5637 cell therapeutic responses. Microarray analysis also demonstrated similar alterations in expression of apoptotic (GADD45B and TP53INP1) and cytoskeleton-related genes (ZMYM6 and RND1) following gemcitabine exposure between 5637 (human) and Oncopig BCCL cells, indicating apoptosis may be triggered through similar signaling pathways. Molecular docking results indicated that swine and humans had similar Dg values between the chemotherapeutics and their target proteins.

Discussion

Taken together, these results suggest the Oncopig could be an attractive animal to model urothelial carcinoma due to similarities in in vitro therapeutic responses compared to human cells.

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.

Shared hotspot mutations in oncogenes position dogs as an unparalleled comparative model for precision therapeutics

Naturally occurring canine cancers have remarkable similarities to their human counterparts. To better understand these similarities, we investigated 671 client-owned dogs from 96 breeds with 23 common tumor types, including those whose mutation profile are unknown (anal sac carcinoma and neuroendocrine carcinoma) or understudied (thyroid carcinoma, soft tissue sarcoma and hepatocellular carcinoma). We discovered mutations in 50 well-established oncogenes and tumor suppressors, and compared them to those reported in human cancers. As in human cancer, TP53 is the most commonly mutated gene, detected in 22.5% of canine tumors overall. Canine tumors share mutational hotspots with human tumors in oncogenes including PIK3CA, KRAS, NRAS, BRAF, KIT and EGFR. Hotspot mutations with significant association to tumor type include NRAS G61R and PIK3CA H1047R in hemangiosarcoma, ERBB2 V659E in pulmonary carcinoma, and BRAF V588E (equivalent of V600E in humans) in urothelial carcinoma. Our findings better position canines as a translational model of human cancer to investigate a wide spectrum of targeted therapies.

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.

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.

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.

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.

Comparative Cancer Cell Signaling in Muscle-Invasive Urothelial Carcinoma of the Bladder in Dogs and Humans

Muscle-invasive urothelial carcinoma (MIUC) is the most common type of bladder malignancy in humans, but also in dogs that represent a naturally occurring model for this disease. Dogs are immunocompetent animals that share risk factors, pathophysiological features, clinical signs and response to chemotherapeutics with human cancer patients. This review summarizes the fundamental pathways for canine MIUC initiation, progression, and metastasis, emerging therapeutic targets and mechanisms of drug resistance, and proposes new opportunities for potential prognostic and diagnostic biomarkers and therapeutics. Identifying similarities and differences between cancer signaling in dogs and humans is of utmost importance for the efficient translation of in vitro research to successful clinical trials for both species.

Characterization of receptor tyrosine kinase activation and biological activity of toceranib phosphate in canine urothelial carcinoma cell lines

Background

Urothelial carcinoma (UC) accounts for > 90% of canine tumors occurring in the urinary bladder. Toceranib phosphate (TOC) is a multi-target receptor tyrosine kinase (RTK) inhibitor that exhibits activity against members of the split kinase family of RTKs. The purpose of this study was to evaluate primary UC tumors and UC cell lines for the expression and activation of VEGFR2, PDGFRα, PDGFRβ, and KIT to assess whether dysregulation of these RTKs may contribute to the observed biological activity of TOC.

Results

Transcript for VEGFR2, PDGFRα, PDGFRβ, and KIT was detected in all UC tissue samples and UC cell lines. The Proteome Profiler™ Human Phospho-RTK Array Kit (R & D Systems) provided a platform to assess phosphorylation of 42 different RTKs in primary UC tumors and UC cell lines. Evidence of PDGFRα and PDGFRβ phosphorylation was present in only 11% or 33% of UC tumors, respectively, and 25% of UC cell lines. Treatment of UC cell lines with TOC had no significant impact on cell proliferation, including UC cell lines with evidence of PDGFRβ phosphorylation.

Conclusions

Phosphorylation of several key RTKs targeted by TOC is present in a small subset of primary UC tumors and UC cell lines, suggesting that these RTKs do not exist in a state of continuous activation. These data suggest that activation of RTKs targeted by TOC is present in a small subset of UC tumors and UC cell lines and that treatment with TOC at physiologically relevant concentrations has no direct anti-proliferative effect on UC cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03027-0.

Basal and Luminal Molecular Subtypes in Naturally-Occurring Canine Urothelial Carcinoma are Associated with Tumor Immune Signatures and Dog Breed

BACKGROUND

Improved therapies are needed for patients with invasive urothelial carcinoma (InvUC). Tailoring treatment to molecular subtypes holds promise, but requires further study, including studies in pre-clinical animal models. Naturally-occurring canine InvUC harbors luminal and basal subtypes, mimicking those observed in humans, and could offer a relevant model for the disease in people.

OBJECTIVE

To further validate the canine InvUC model, clinical and tumor characteristics associated with luminal and basal subtypes in dogs were determined, with comparison to findings from humans.

METHODS

RNA sequencing (RNA-seq) analyses were performed on 56 canine InvUC tissues and bladder mucosa from four normal dogs. Data were aligned to CanFam 3.1, and differentially expressed genes identified. Data were interrogated with panels of genes defining luminal and basal subtypes, immune signatures, and other tumor features. Subject and tumor characteristics, and outcome data were obtained from medical records.

RESULTS

Twenty-nine tumors were classified as luminal and 27 tumors as basal subtype. Basal tumors were strongly associated with immune infiltration (OR 52.22, 95%CI 4.68-582.38, P = 0.001) and cancer progression signatures in RNA-seq analyses, more advanced clinical stage, and earlier onset of distant metastases in exploratory analyses (P = 0.0113). Luminal tumors were strongly associated with breeds at high risk for InvUC (OR 0.06, 95%CI 0.01 -0.37, P = 0.002), non-immune infiltrative signatures, and less advanced clinical stage.

CONCLUSIONS

Dogs with InvUC could provide a valuable model for testing new treatment strategies in the context of molecular subtype and immune status, and the search for germline variants impacting InvUC onset and subtype.

Perspective: Humanized Pig Models of Bladder Cancer

Bladder cancer (BC) is the 10th most common neoplasia worldwide and holds expensive treatment costs due to its high recurrence rates, resistance to therapy and the need for lifelong surveillance. Thus, it is necessary to improve the current therapy options and identify more effective treatments for BC. Biological models capable of recapitulating the characteristics of human BC pathology are essential in evaluating the effectiveness of new therapies. Currently, the most commonly used BC models are experimentally induced murine models and spontaneous canine models, which are either insufficient due to their small size and inability to translate results to clinical basis (murine models) or rarely spontaneously observed BC (canine models). Pigs represent a potentially useful animal for the development of personalized tumors due to their size, anatomy, physiology, metabolism, immunity, and genetics similar to humans and the ability to experimentally induce tumors. Pigs have emerged as suitable biomedical models for several human diseases. In this sense, the present perspective focuses on the genetic basis for BC; presents current BC animal models available along with their limitations; and proposes the pig as an adequate animal to develop humanized large animal models of BC. Genetic alterations commonly found in human BC can be explored to create genetically defined porcine models, including the BC driver mutations observed in the FGFR3, PIK3CA, PTEN, RB1, HRAS, and TP53 genes. The development of such robust models for BC has great value in the study of pathology and the screening of new therapeutic and diagnostic approaches to the disease.

Ultrasound-guided transurethral urinary bladder biopsy using an endoscopic biopsy forceps in dogs: 27 cases (2016-2019)

OBJECTIVES

To describe an ultrasound-guided transurethral bladder biopsy technique using endoscopic forceps and its results in dogs of different sizes with different lesion locations.

MATERIALS AND METHODS

Medical records of dogs that underwent ultrasound-guided transurethral bladder biopsy with endoscopic forceps were retrospectively reviewed. Patient signalment, lesion location, use of urinary catheter as a guide, outcome of the procedure and histopathology results were retrieved.

RESULTS

Twenty-seven dogs underwent this procedure. Biopsy samples were successfully obtained in 23 dogs. Insertion of the endoscopic forceps without a urinary catheter allowed the procedure to be performed in patients with a small urethral diameter without complication. The procedure was unsuccessful in dogs with a urethral diameter smaller than the outer diameter of the biopsy forceps (i.e. 1.8 mm), either due to small patient size or obstructive urethral lesion. All biopsy samples allowed histopathological diagnosis. No complications were reported after the procedure.

CLINICAL SIGNIFICANCE

This non-invasive biopsy technique should be considered in patients with bladder lesions in which histopathological diagnosis is needed, especially when endoscopic examination is not feasible. By use of the Doppler mode, biopsy retrieval was safe also when the lesion ​was highly vascularised.

Cutaneous seeding of transitional cell carcinoma of the urinary bladder after placement of a subcutaneous ureteral bypass device in a dog with bilateral ureteral obstruction

CASE DESCRIPTION

A 12-year-old spayed female Jack Russell Terrier was presented with pollakiuria and stranguria.

CLINICAL FINDINGS

Transitional cell carcinoma (TCC) of the urinary bladder trigone and urethra was diagnosed via CT, cystoscopic, and histologic examinations. Azotemia developed 2 weeks following diagnosis, secondary to bilateral ureteral obstruction.

TREATMENT AND OUTCOME

Percutaneous antegrade ureteral stenting was unsuccessful; therefore, a subcutaneous ureteral bypass (SUB) device with 2 nephrostomy and 1 cystostomy catheters was surgically placed. Two months following placement of the SUB device, the dog developed a firm, multilobulated cutaneous mass at the site of the subcutaneous access port of the SUB device. Results of cytologic examination of cells aspirated from the mass were consistent with TCC. Within 1 month of confirmation of TCC of the cutaneous mass, the mass was ulcerated and infected, and the dog was euthanized because of signs of pain and perceived poor quality of life.

CLINICAL RELEVANCE

Seeding of neoplastic cells is a known complication of needle aspiration or biopsy or surgery in people and dogs with carcinomas. The occurrence of TCC at the SUB port site suggested caution with the placement of a SUB device in dogs with obstructive TCC.

Review of Histological Grading Systems in Veterinary Medicine

Tumor grading is a method to quantify the putative clinical aggressiveness of a neoplasm based on specific histological features. A good grading system should be simple, easy to use, reproducible, and accurately segregate tumors into those with low versus high risk. The aim of this review is to summarize the histological and, when available, cytological grading systems applied in veterinary pathology, providing information regarding their prognostic impact, reproducibility, usefulness, and shortcomings. Most of the grading schemes used in veterinary medicine are developed for common tumor entities. Grading systems exist for soft tissue sarcoma, osteosarcoma, multilobular tumor of bone, mast cell tumor, lymphoma, mammary carcinoma, pulmonary carcinoma, urothelial carcinoma, renal cell carcinoma, prostatic carcinoma, and central nervous system tumors. The prognostic relevance of many grading schemes has been demonstrated, but for some tumor types the usefulness of grading remains controversial. Furthermore, validation studies are available only for a minority of the grading systems. Contrasting data on the prognostic power of some grading systems, lack of detailed instructions in the materials and methods in some studies, and lack of data on reproducibility and validation studies are discussed for the relevant grading systems. Awareness of the limitations of grading is necessary for pathologists and oncologists to use these systems appropriately and to drive initiatives for their improvement.

Assessment of urinary 15-F2 -isoprostanes in dogs with urothelial carcinoma of the urinary bladder and other lower urinary tract diseases

Background

The 15‐F₂‐isoprostanes are by‐products of oxidative stress and are increased in the urine of people with lower urinary tract diseases (LUTD), especially urinary neoplasia. Urothelial carcinoma (UC) is the most common urinary neoplasm in dogs. Earlier detection of UC by noninvasive means could lead to improved outcomes. Urinary 15‐F₂‐isoprostanes potentially could provide this means, but have not been evaluated in dogs with UC.

Objective

The objective of this study was to measure urinary 15‐F₂‐isoprostanes in dogs with UC and dogs with other LUTD.

Animals

One hundred seventeen dogs: 46 dogs with UC, 30 dogs with LUTD, and 25 control dogs.

Methods

Any dog that was presented with dysuria was eligible for inclusion. Diagnosis of UC was confirmed histologically. Urinalysis was performed in each case, and 15‐F₂‐isoprostanes quantified by gas chromatography‐negative ion chemical ionization‐mass spectrometry (GC‐NICI‐MS) and normalized to urinary creatinine concentration.

Results

Dogs with urinary diseases (UC + LUTD) had higher median urinary 15‐F₂‐isoprostanes when compared to control dogs (5.92 ng/mg [range, 0.46‐31.03] vs 3.73 [range, 1.8‐7.98]; P = .02). Urinary 15‐F₂‐isoprostanes were similar in dogs with UC (5.33 ng/mg [range, 0.46‐31.03]) compared to dogs with LUTD (6.29 ng/mg [range, 0.54‐18.93]; P = .47) and control dogs (P = .06). Dogs with UC had higher qualitative measures of proteinuria (P = .004), hematuria (P = .01), and epithelial cells on urinalysis (P = .002) compared to the other groups.

Conclusions and Clinical Importance

Urinary F₂‐isoprostanes are not useful for the detection of UC in dogs. Future research could evaluate urinary 15‐F₂‐isoprostanes as a marker of inflammation in disease progression and prognosis.

Porcine cancer models: potential tools to enhance cancer drug trials

INTRODUCTION

The amount of time and money invested into cancer drug research, development, and clinical trials has continually increased over the past few decades. Despite record high cancer drug approval rates, cancer remains a leading cause of death. This suggests the need for more effective tools to help bring novel therapies to clinical practice in a timely manner.

AREAS COVERED

In this review, current issues associated with clinical trials are discussed, specifically focusing on poor accrual rates and time for trial completion. In addition, details regarding preclinical studies required before advancing to clinical trials are discussed, including advantages and limitations of current preclinical animal cancer models and their relevance to human cancer trials. Finally, new translational porcine cancer models (Oncopig Cancer Model (OCM)) are presented as potential co-clinical trial models.

EXPERT OPINION

In order to address issues impacting the poor success rate of oncology clinical trials, we propose the incorporation of the transformative OCM 'co-clinical trial' pathway into the cancer drug approval process. Due to the Oncopig's high homology to humans and similar tumor phenotypes, their utilization can provide improved preclinical prediction of both drug safety and efficacy prior to investing significant time and money in human clinical trials.

RNAseq expression patterns of canine invasive urothelial carcinoma reveal two distinct tumor clusters and shared regions of dysregulation with human bladder tumors

BACKGROUND

Invasive urothelial carcinoma (iUC) is highly similar between dogs and humans in terms of pathologic presentation, molecular subtypes, response to treatment and age at onset. Thus, the dog is an established and relevant model for testing and development of targeted drugs benefiting both canine and human patients. We sought to identify gene expression patterns associated with two primary types of canine iUC tumors: those that express a common somatic mutation in the BRAF gene, and those that do not.

METHODS

We performed RNAseq on tumor and normal tissues from pet dogs. Analysis of differential expression and clustering, and positional and individual expression was used to develop gene set enrichment profiles distinguishing iUC tumors with and without BRAFV595E mutations, as well as genomic regions harboring excessive numbers of dysregulated genes.

RESULTS

We identified two expression clusters that are defined by the presence/absence of a BRAFV595E (BRAFV600E in humans) somatic mutation. BRAFV595E tumors shared significantly more dysregulated genes than BRAF wild-type tumors, and vice versa, with 398 genes differentiating the two clusters. Key genes fall into clades of limited function: tissue development, cell cycle regulation, immune response, and membrane transport. The genomic site with highest number of dysregulated genes overall lies in a locus corresponding to human chromosome 8q24, a region frequently amplified in human urothelial cancers.

CONCLUSIONS

These data identify critical sets of genes that are differently regulated in association with an activating mutation in the MAPK/ERK pathway in canine iUC tumors. The experiments also highlight the value of the canine system in identifying expression patterns associated with a common, shared cancer.

Predictive modeling for cancer drug discovery using canine models

INTRODUCTION

Rodent models of cancer lack many features associated with the disease in humans. Because dogs closely share an environment with humans, as well as comparable pathophysiology of cancer, they represent a powerful model with which to study novel approaches to cancer treatment.

AREAS COVERED

The authors summarize the weaknesses of rodent models of cancer and the ongoing need for better animal models with which to study potential therapeutic approaches. The homology of cancer in dogs and humans is described, along with examples specific to several common cancer types.

EXPERT OPINION

Laboratory mice and rats will continue to play a central role in cancer research; however, because of a variety of limitations, pet dogs with spontaneous cancer offer unique opportunities for research and should be included in the preclinical development of therapeutic compounds. Environmental homology between dogs and humans, along with biological and molecular similarities present circumstances that strengthen the translational rigor of studies conducted using canine patients. Progress will depend on a sufficient number of dogs to be diagnosed with cancer and available for use in studies; and essential to this will be the availability of enhanced resources for diagnosis of cancer in canine patients and reliable coordination between research scientists, veterinarians, and physicians.

Naturally-Occurring Invasive Urothelial Carcinoma in Dogs, a Unique Model to Drive Advances in Managing Muscle Invasive Bladder Cancer in Humans

There is a great need to improve the outlook for people facing urinary bladder cancer, especially for patients with invasive urothelial carcinoma (InvUC) which is lethal in 50% of cases. Improved outcomes for patients with InvUC could come from advances on several fronts including emerging immunotherapies, targeted therapies, and new drug combinations; selection of patients most likely to respond to a given treatment based on molecular subtypes, immune signatures, and other characteristics; and prevention, early detection, and early intervention. Progress on all of these fronts will require clinically relevant animal models for translational research. The animal model(s) should possess key features that drive success or failure of cancer drugs in humans including tumor heterogeneity, genetic-epigenetic crosstalk, immune cell responsiveness, invasive and metastatic behavior, and molecular subtypes (e.g., luminal, basal). Experimental animal models, while essential in bladder cancer research, do not possess these collective features to accurately predict outcomes in humans. These key features, however, are present in naturally-occurring InvUC in pet dogs. Canine InvUC closely mimics muscle-invasive bladder cancer in humans in cellular and molecular features, molecular subtypes, immune response patterns, biological behavior (sites and frequency of metastasis), and response to therapy. Thus, dogs can offer a highly relevant animal model to complement other models in research for new therapies for bladder cancer. Clinical treatment trials in pet dogs with InvUC are considered a win-win-win scenario; the individual dog benefits from effective treatment, the results are expected to help other dogs, and the findings are expected to translate to better treatment outcomes in humans. In addition, the high breed-associated risk for InvUC in dogs (e.g., 20-fold increased risk in Scottish Terriers) offers an unparalleled opportunity to test new strategies in primary prevention, early detection, and early intervention. This review will provide an overview of canine InvUC, summarize the similarities (and differences) between canine and human InvUC, and provide evidence for the expanding value of this canine model in bladder cancer research.

An ultrasound based platform for image-guided radiotherapy in canine bladder cancer patients

Background and purpose

Ultrasound (US) is a non-invasive, non-radiographic imaging technique with high spatial and temporal resolution that can be used for localizing soft-tissue structures and tumors in real-time during radiotherapy (RT) (inter- and intra-fraction). A comprehensive approach incorporating an in-house 3D-US system within RT is presented. This system is easier to adopt into existing treatment protocols than current US based systems, with the aim of providing millimeter intra-fraction alignment errors and sensitivity to track intra-fraction bladder movement.

Materials and methods

An in-house integrated US manipulator and platform was designed to relate the computed tomographic (CT) scanner, 3D-US and linear accelerator coordinate systems. An agar-based phantom with measured speed of sound and densities consistent with tissues surrounding the bladder was rotated (0–45°) and translated (up to 55 mm) relative to the US and CT coordinate systems to validate this device. After acquiring and integrating CT and US images into the treatment planning system, US-to-US and US-to-CT images were co-registered to re-align the phantom relative to the linear accelerator.

Results

Statistical errors from US-to-US registrations for various patient orientations ranged from 0.1 to 1.7 mm for x, y, and z translation components, and 0.0–1.1° for rotational components. Statistical errors from US-to-CT registrations were 0.3–1.2 mm for the x, y and z translational components and 0.1–2.5° for the rotational components.

Conclusions

An ultrasound-based platform was designed, constructed and tested on a CT/US tissue-equivalent phantom to track bladder displacement with a statistical uncertainty to correct and track inter- and intra-fractional displacements of the bladder during radiation treatments.

Dog10K: an international sequencing effort to advance studies of canine domestication, phenotypes and health

Dogs are the most phenotypically diverse mammalian species, and they possess more known heritable disorders than any other non-human mammal. Efforts to catalog and characterize genetic variation across well-chosen populations of canines are necessary to advance our understanding of their evolutionary history and genetic architecture. To date, no organized effort has been undertaken to sequence the world's canid populations. The Dog10K Consortium (http://www.dog10kgenomes.org) is an international collaboration of researchers from across the globe who will generate 20× whole genomes from 10 000 canids in 5 years. This effort will capture the genetic diversity that underlies the phenotypic and geographical variability of modern canids worldwide. Breeds, village dogs, niche populations and extended pedigrees are currently being sequenced, and de novo assemblies of multiple canids are being constructed. This unprecedented dataset will address the genetic underpinnings of domestication, breed formation, aging, behavior and morphological variation. More generally, this effort will advance our understanding of human and canine health.

Urologic Oncology

Primary renal tumors are an uncommon diagnosis in small animals. Presentation, treatment, and prognosis depend on tumor type. Surgery with or without chemotherapy are the mainstays of treatment. Transitional cell carcinoma is the most common tumor of the urinary system. Clinical signs include hematuria, stranguria, and pollakiuria. Metastatic disease can develop over time within medial iliac lymph nodes, lungs, and vertebrae. Treatment of transitional cell carcinoma centers on chemotherapy with mitoxantrone, vinblastine, or carboplatin. Other agents used with success, include toceranib phosphate and chlorambucil. Interventional surgery, such as stenting and laser ablation, is used in a palliative setting addressing urinary obstruction.

Canine Cancer Genomics: Lessons for Canine and Human Health

Dogs are second only to humans in medical surveillance and preventative health care, leading to a recent perception of increased cancer incidence. Scientific priorities in veterinary oncology have thus shifted, with a demand for cancer genetic screens, better diagnostics, and more effective therapies. Most dog breeds came into existence within the last 300 years, and many are derived from small numbers of founders. Each has undergone strong artificial selection, in which dog fanciers selected for many traits, including body size, fur type, color, skull shape, and behavior, to create novel breeds. The adoption of the breed barrier rule-no dog may become a registered member of a breed unless both its dam and its sire are registered members-ensures a relatively closed genetic pool within each breed. As a result, there is strong phenotypic homogeneity within breeds but extraordinary phenotypic variation between breeds. One consequence of this is the high level of breed-associated genetic disease. We and others have taken advantage of this to identify genes for a large number of canine maladies for which mouse models do not exist, particularly with regard to cancer.

Fatty Acid Patterns Detected By Ambient Ionization Mass Spectrometry in Canine Invasive Urothelial Carcinoma From Dogs of Different Breeds

Background:

In early work ambient ionization mass spectrometry (MS) revealed lipid patterns distinguishing muscle invasive bladder cancer (invasive urothelial carcinoma, InvUC) from normal urothelium. A new ambient ionization MS approach, touch spray MS (TS-MS) can rapidly generate mass spectra in real time, potentially in a point-of-care setting. A tissue sample removed from a patient is touched by a probe, and mass spectra generated within seconds.

Objective:

To validate TS-MS methods using specimens from naturally-occurring InvUC in dogs where the cancer closely mimics the human condition, and to demonstrate proof-of-concept that TS-MS can elucidate lipid patterns distinguishing InvUC from normal urothelium.

Methods:

Samples of normal urothelium and InvUC from dogs of several breeds were analyzed by TS-MS with correlative histopathology across each sample. Results were compared to those obtained with desorption electrospray ionization mass spectrometry (DESI-MS), a more traditional method. Data were analyzed by Principal Component Analysis and Linear Discriminant Analysis.

Results:

Lipid patterns identified by TS-MS, as well as by DESI-MS, differed between InvUC and normal urothelium with m/z 281.5 (oleic acid) and m/z 563.5 (oleic acid dimer) substantially contributing to the differences. Using histologic diagnosis as the gold standard, TS-MS had a global prediction rate of 93%.

Conclusions:

TS-MS can be used to identify lipid patterns that differentiate canine InvUC from normal urothelium. Optimization of TS-MS could lead to a point-of-care approach to distinguish cancer from normal in ex vivo tissues in real time, and to define biochemical processes leading to cancer development and progression.