Pretreatment tumor prostaglandin E2 concentration and cyclooxygenase-2 expression are not associated with the response of canine naturally occurring invasive urinary bladder cancer to cyclooxygenase inhibitor therapy

Expression of vascular endothelial growth factor receptor-2, epidermal growth factor receptor, cyclooxygenase-2, survivin, E-cadherin and Ki-67 in canine nasal carcinomas and sarcomas - a pilot study

Background

Malignant (intra-) nasal tumors (NTs) are the most common cause of chronic nasal discharge in dogs. Besides radiation therapy, palliative therapy is necessary in some dogs. Therefore, studies on receptor expression have supported the utility of tyrosine kinase inhibitors (TKI) in dogs with nasal carcinomas. However, studies on receptor expression in nasal sarcomas are lacking.

Materials and methods

This study evaluated the expression of vascular endothelial growth factor receptor-2 (VEGFR-2), epidermal growth factor receptor (EGFR), cyclooxigenase-2 (COX-2), Ki-67, survivin and E-cadherin in nasal carcinomas and sarcomas and compared it with tumor (T) categories based on computed tomography (CT).

Results

In 26 dogs with NTs, cross sectional imaging and upper airway endoscopy with guided biopsy collection were performed, followed by histopathological examination of NTs, revealing 19 epithelial and 7 mesenchymal tumors. While EGFR and E-cadherin were only expressed by carcinomas, the following markers were expressed by both carcinomas and sarcomas without significant differences between tumor types and T-categories: VEGFR-2 (carcinomas and sarcomas 100%), COX-2 (carcinomas 63%, sarcomas 57%), survivin (carcinomas 100%, sarcomas 86%) and Ki-67 (median expression of 28.5% in carcinomas and 17.3% in sarcomas).

Conclusion

Based on similarities in marker expression between canine carcinomas and sarcomas, clinical studies should further elucidate the use of TKI or COX-2 inhibitors as additional therapy in dogs with nasal sarcomas.

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.

Molecular Markers in Urinary Bladder Cancer: Applications for Diagnosis, Prognosis and Therapy

Cancer of the urinary bladder is a neoplasm with considerable importance in veterinary medicine, given its high incidence in several domestic animal species and its life-threatening character. Bladder cancer in companion animals shows a complex and still poorly understood biopathology, and this lack of knowledge has limited therapeutic progress over the years. Even so, important advances concerning the identification of tumour markers with clinical applications at the diagnosis, prognosis and therapeutic levels have recently been made, for example, the identification of pathological BRAF mutations. Those advances are now facilitating the introduction of targeted therapies. The present review will address such advances, focusing on small animal oncology and providing the reader with an update on this field. When appropriate, comparisons will be drawn with bladder cancer in human patients, as well as with experimental models of the disease.

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.

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.

Correlation of BRAF Variant V595E, Breed, Histological Grade and Cyclooxygenase-2 Expression in Canine Transitional Cell Carcinomas

The presence of BRAF variant V595E, as well as an increased cyclooxygenase-2 (COX-2) expression in canine transitional cell carcinoma (TCC) are well-described in the literature. The aim of the present study was to investigate the correlation between breed (terrier versus non-terrier dogs), histological grade, COX-2 expression, and BRAF mutation in canine TCC. Therefore, transmural TCC biopsies from 65 dogs (15 terriers, 50 non-terriers) were graded histologically into low- and high-grade. Immunohistochemical evaluation of the intensity of COX-2 expression was performed using an immunoreactive score (IRS). Exon 15 of chromosome 16 was examined for the BRAF variant c.1799T>A by TaqMan^® SNP assay. TCC was low-grade in 20 cases (one terrier, 19 non-terriers) and high-grade in 45 cases (14 terriers, 31 non-terriers). Contrary to humans, histological grade was not significantly correlated to the intensity of COX-2 expression. BRAF mutation was detected in 11/15 (73%) TCC of terriers and in 18/50 (36%) TCC of non-terriers. Histological grade and BRAF mutation were not correlated significantly (p = 0.2912). Terriers had a considerably higher prevalence of high-grade tumors (p < 0.0001), as well as of BRAF mutation (p ≤ 0.05) compared to non-terriers. In non-terriers, neoplasms with BRAF mutation showed a significantly higher intensity of COX-2 expression than those without BRAF mutation (p ≤ 0.05). In conclusion, in contrast to humans, testing for BRAF mutation in canine TCC is a sensitive diagnostic method especially in terriers (73%) and may be recommended as a screening test. However, evidence of BRAF mutation in canine TCC is not a predictor for the histological grade. Moreover, a positive correlation between histological grade and the intensity of COX-2 expression was not found. Further studies are necessary to clarify the clinical and prognostic relevance of the elevated intensity of COX-2 expression of TCC with BRAF mutation detected in non-terriers.

Vinorelbine rescue therapy for dogs with primary urinary bladder carcinoma

The goal of this study was to evaluate the anti-tumour activity and toxicoses of vinorelbine as a palliative rescue therapy for dogs with primary urinary bladder carcinoma. Thirteen dogs refractory to prior chemotherapeutics and one dog naïve to chemotherapeutic treatment were enrolled. Vinorelbine (15 mg m(-2) IV) was administered intravenously along with concurrent oral anti-inflammatory drugs, if tolerated. A median of six doses of vinorelbine (range: 1-16) was administered. Two dogs (14%) had partial responses, and eight (57%) experienced stable disease. Subjective improvement in clinical signs was noted in 11 dogs (78%). Adverse events were mild and primarily haematological in nature. Median time to progression was 93 days (range: 20-239 days). Median survival time for all dogs was 187 days; median survival for 13 pre-treated dogs was 207 days. Vinorelbine may have utility in the management of canine primary urinary bladder carcinoma and should be evaluated in a prospective study.

Prevalence of 5-lipoxygenase expression in canine osteosarcoma and the effects of a dual 5-lipoxygenase/cyclooxygenase inhibitor on osteosarcoma cells in vitro and in vivo

Canine osteosarcoma is an insidious disease with few effective treatment modalities; therefore, use of pharmacologic intervention to improve mortality or morbidity is constantly sought. The use of cyclooxygenase enzyme inhibitors has been an area of interest with limited efficacy based on retrospective examination of tumor expression and in vivo cell proliferation models. Recently, examination of dual cyclooxygenase and 5-lipoxygenase inhibitors in human and canine oncology suggests that 5-lipoxygenase inhibitors may be an effective approach in vitro and during tumor induction in rodent models. Therefore, the authors decided to examine 5-lipoxygenase expression in primary canine osteosarcoma samples and have shown that approximately 65% of osteosarcomas label positive for cytoplasmic 5-lipoxygenase. Further examination of a cell culture and xenograft model shows similar 5-lipoxygenase expression. Surprisingly, a canine 5-lipoxygenase inhibitor (tepoxalin) significantly reduced cell proliferation at physiologic doses in vitro and diminished xenograft tumor growth in nude mice, suggesting that further investigation is needed. Traditionally, 5-lipoxygense leads to production of lipid mediators, such as leukotriene B(4) and 5-oxo-eicosatetraenoic acid, which, when added back to the media of tepoxalin-treated cells, did not recover cell proliferation. The lack of nuclear staining in primary and xenografted tumors and the lack of response to eicoasanoids suggest that lipid mediator production is not the primary means by which tepoxalin acts to alter proliferation. Regardless of the mechanisms involved in retarding cell proliferation, future investigation is warranted.

Cyclooxygenase-2 expression in animal cancers

Cyclooxygenase (COX; also known as prostaglandin endoperoxide synthase) is a key enzyme in the biochemical pathway leading to the synthesis of prostaglandins. A large amount of epidemiological and experimental evidence supports a role for COX-2, the inducible form of the enzyme, in human tumorigenesis, notably in colorectal cancer. COX-2 mediates this role through the production of PGE(2) that acts to inhibit apoptosis, promote cell proliferation, stimulate angiogenesis, and decrease immunity. Similarly, COX-2 is believed to be involved in the oncogenesis of some cancers in domestic animals. Here, the author reviews the current knowledge on COX-2 expression and role in cancers of dogs, cats, and horses. Data indicate that COX-2 upregulation is present in many animal cancers, but there is presently not enough information to clearly define the prognostic significance of COX-2 expression. To date, only few reports document an association between COX-2 expression and survival, notably in canine mammary cancers and osteosarcomas. Some evidence suggests that COX inhibitors could be useful in the prevention and/or treatment of certain cancers in domestic animals, the best example being urinary transitional cell carcinomas in dogs. However, determination of the levels of COX-2 in a tumor does not appear to be a good prognostic factor or a good indicator for the response to nonsteroidal anti-inflammatory drug therapy. Clearly, additional research, including the development of in vitro cell systems, is needed to determine if COX-2 expression can be used as a reliable prognostic factor and as a definite therapeutic target in animal cancers.

Effect of cyclooxygenase inhibitors in a xenograft model of canine mammary tumours

Inhibition of cyclooxygenase-2 (COX-2) represents a possible avenue for the prevention and/or treatment of some cancers. Our goal was to compare the effect of a selective inhibitor of COX-2, deracoxib, and a COX-1 and -2 inhibitor, piroxicam, on the growth of canine mammary tumours in a murine model. CMT-9 was used to induce xenografts in nude mice. Mice were treated with piroxicam (0.6 mg kg(-1)), deracoxib (6 mg kg(-1)) or a control solution. Tumour volumes between 0 and 24 days post-treatment showed no significant difference between all groups. A second series of experiments was performed with a higher dose of piroxicam (0.9 mg kg(-1)). Tumour volumes between 14 and 21 days post-treatment were significantly smaller in piroxicam-treated mice compared with controls. These results demonstrate that COX inhibition reduced the growth of canine mammary cancer xenografts in mice, suggesting that COX inhibitors could have a positive effect in dogs.

3-Phosphoinositide-dependent protein kinase-1/Akt signalling and inhibition in a canine prostate carcinoma cell line

Deregulation of the 3-phosphoinositide-dependent protein kinase-1 (PDK-1)/Akt signalling pathway is associated with prostate cancer development and progression. Inhibition of PDK-1/Akt signalling can be achieved using structurally optimized celecoxib derivatives such as OSU-03012. In this study, we treated the novel canine prostate cancer cell line, Ace-1, with OSU-03012 or dimethyl sulphoxide in vitro. We found that Akt was constitutively phosphorylated in the canine prostate cancer cell line Ace-1 and that there was a dose-dependent decrease in cell viability, and Akt and glycogen synthase kinase-3beta phosphorylation, in response to OSU-03012 treatment. This was accompanied by a dose-dependent increase in apoptosis. These data suggest that Akt signalling pathway inhibition is a potential strategy for the treatment of dogs with prostate cancer and that canine prostate cancer is a relevant large animal model for evaluating Akt pathway inhibitors such as OSU-03012 for use in people.

Review Paper: Cancer Chemopreventive Compounds and Canine Cancer

Canine cancer has become more prevalent in recent years because of increased life expectancy and greater attention to the health of pets. The range of cancers seen in dogs is as diverse as that in human patients, and despite more intensive therapeutic interventions, fatality rates remain unacceptably high in both species. Chemoprevention is therefore an important means of confronting this disease. Because domestic pets share our environment, greater cross-application and study of the protumorigenic and antitumorigenic factors in our shared environment will benefit all species, leading to the development of new families of less toxic antitumorigenic compounds based on novel and established molecular targets. Currently, the most interesting cancer preventive agents are nonsteroidal anti-inflammatory drugs, peroxisome proliferator-activated receptor-γ ligands, and dietary compounds. This article provides an overview of what is known about how these agents affect molecular signaling in neoplastic disease, with reference to reported application and/or study in dogs where available.

Cyclooxygenase-2 Expression in Equine Tumors

The enzyme cyclooxygenase-2 (COX-2) is expressed in some tumor and stromal tissues, and catalyzes production of prostaglandins with growth stimulatory, antiapoptotic, proangiogenic, and immunosuppressive properties. Pharmacologic inhibition of COX-2 is associated with antitumor activity in various human and canine malignancies. The purpose of this study was to assess COX-2 expression in a series of equine sarcoids, melanomas, and squamous-cell carcinomas (SCC). COX-2 expression was assessed in formalin-fixed paraffin-embedded tissues from 14 sarcoids, 11 melanomas, and 37 SCC that represent various anatomic sites by using standard immunohistochemical methods. COX-2 was expressed in 2 of 14 sarcoids, 7 of 11 melanomas, and 32 of 37 SCC, 56% of which demonstrated moderate-to-strong immunoreactivity. There were no differences in expression between anatomic sites. In conclusion, most equine SCC and many melanomas appear to express COX-2 and thus could respond to COX-2 inhibitor therapy.

Cyclooxygenase-2 dependent and independent antitumor effects induced by celecoxib in urinary bladder cancer cells

Transitional cell carcinoma of the urinary bladder is the second most common genitourinary malignancy in people in the United States. Cyclooxygenase-2 (COX-2) is overexpressed in bladder cancer. COX-2 inhibitors have had antitumor activity against bladder cancer, but the mechanisms of action are unclear. Clinically relevant concentrations of COX-2 inhibitors fail to inhibit proliferation in standard in vitro assays. In pilot experiments, different culture conditions [standard monolayer, modified monolayer, soft agar, collagen, and poly(2-hydroxyethyl methacrylate)-coated plates] were assessed to determine conditions suitable for the study of COX inhibitor growth-inhibitory effects. This was followed by studies of the effects of clinically relevant concentrations of a selective COX-2 inhibitor (celecoxib) on urinary bladder cancer cell lines (HT1376, TCCSUP, and UMUC3). Celecoxib (<or=5 micromol/L) inhibited proliferation of COX-2-expressing HT1376 cells in soft agar and modified monolayer cell culture conditions in a COX-2-dependent manner. COX-2 expression, however, did not always correlate with response to celecoxib. TCCSUP cells that express COX-2 were minimally affected by celecoxib, and UMUC3 cells that lack COX-2 expression were modestly inhibited by the drug. When UMUC3(Cox-2/Tet) cells overexpressing COX-2 under the control of tetracycline-inducible promoter were treated with celecoxib in modified monolayer cell culture, growth inhibition was found to be associated with changes in the expression of pRb. Not surprisingly, the proliferation of all cell lines was inhibited by excessively high concentrations of celecoxib. In conclusion, the modified culture conditions allowed detection of COX-2-dependent and COX-2-independent growth-inhibitory activity of celecoxib in urinary bladder cancer cells.

Expression of cyclooxygenase-2, P-glycoprotein and multi-drug resistance-associated protein in canine transitional cell carcinoma

Cyclooxygenase-2 (COX-2), P-glycoprotein (P-gp) and multi-drug resistance-associated protein (MRP) are considered important tumor-associated proteins in humans and dogs. In the present study, we immunohistochemically evaluated the expression of these proteins in canine patients with transitional cell carcinoma (TCC). Of 52 cases, 30 (57.7%) were positive for COX-2, 40 (76.9%) for P-gp, and only 10 (19.2%) for MRP. In addition, 27 samples (27/52, 51.9%) were positive for two markers, while 3 (5.7%) and 5 (9.6%) cases were positive and negative, respectively, for all three markers. No significant correlations were seen for COX-2 and P-gp on Fisher's exact test and Mann-Whitney's test, but a significance was seen on Spearman's rank correlation analysis using the IHC scoring system (P=0.043). These results suggest that P-gp expression is induced by overexpression of COX-2 in canine patients with TCC.