Canine Cancer Cell Research Articles

The effect of dichloroacetate in canine prostate adenocarcinomas and transitional cell carcinomas in vitro.

The Warburg effect describes the ability of cancer cells to produce energy via aerobic glycolysis instead of oxidative phosphorylation of pyruvate. This deviation in mitochondrial metabolism inhibits apoptosis, allowing increased proliferation under conditions of reduced oxygen levels. Dichloroacetate (DCA) was successfully used in several human cancer cell lines to reactivate oxidative phosphorylation in mitochondria. The aim of this study was the characterization and response of canine cancer cell lines after DCA exposure. The effect of 10mM DCA was characterized in vitro on a set of six canine prostate adenocarcinoma and transitional cell carcinoma (TCC) derived cell lines. Cell counts, lactate levels, apoptosis, expression of apoptotic proteins, survival factors and different miRNAs were analyzed. Additionally, metabolic activity, mitochondrial activity and proliferation were investigated. DCA significantly decreased cell number of all but one utilized cell lines and leads to a significant reduction of lactate release. Decreased survivin levels were found in all cell lines, two of which presented a significant reduction in metabolic activity. Increased miR-375 levels were measured in all TCC cell lines. Reactivation of pyruvate dehydrogenase and an elevated mitochondrial activity appear to induce the transition from aerobic glycolysis back to oxidative phosphorylation. Further, these results display that DCA treatment has a suppressant effect on proliferation of canine cancer cells.

Intrinsic Radiosensitivity and Cellular Characterization of 27 Canine Cancer Cell Lines.

Canine cancer cell lines have progressively been developed, but are still underused resources for radiation biology research. Measurement of the cellular intrinsic radiosensitivity is important because understanding the difference may provide a framework for further elucidating profiles for prediction of radiation therapy response. Our studies have focused on characterizing diverse canine cancer cell lines in vitro and understanding parameters that might contribute to intrinsic radiosensitivity. First, intrinsic radiosensitivity of 27 canine cancer cell lines derived from ten tumor types was determined using a clonogenic assay. The 27 cell lines had varying radiosensitivities regardless tumor type (survival fraction at 2 Gy, SF2 = 0.19–0.93). In order to understand parameters that might contribute to intrinsic radiosensitivity, we evaluated the relationships of cellular radiosensitivity with basic cellular characteristics of the cell lines. There was no significant correlation of SF2 with S-phase fraction, doubling time, chromosome number, ploidy, or number of metacentric chromosomes, while there was a statistically significant correlation between SF2 and plating efficiency. Next, we selected the five most radiosensitive cell lines as the radiosensitive group and the five most radioresistant cell lines as the radioresistant group. Then, we evaluated known parameters for cell killing by ionizing radiation, including radiation-induced DNA double strand break (DSB) repair and apoptosis, in the radiosensitive group as compared to the radioresistant group. High levels of residual γ-H2AX foci at the sites of DSBs were present in the four out of the five radiosensitive canine cancer cell lines. Our studies suggested that substantial differences in intrinsic radiosensitivity exist in canine cancer cell lines, and radiation-induced DSB repair was related to radiosensitivity, which is consistent with previous human studies. These data may assist further investigations focusing on the detection of DSB for predicting individual response to radiation therapy for dogs, regardless of tumor type.

The Flint Animal Cancer Center (FACC) Canine Tumour Cell Line Panel: a resource for veterinary drug discovery, comparative oncology and translational medicine

Mammalian cell tissue culture has been a critical tool leading to our current understanding of cancer including many aspects of cellular transformation, growth and response to therapies. The current use of large panels of cell lines with associated phenotypic and genotypic information now allows for informatics approaches and in silico screens to rapidly test hypotheses based on simple as well as complex relationships. Current cell line panels with large amounts of associated drug sensitivity and genomics data are comprised of human cancer cell lines (i.e. NCI60 and GDSC). There is increased recognition of the contribution of canine cancer to comparative cancer research as a spontaneous large animal model with application in basic and translational studies. We have assembled a panel of canine cancer cell lines to facilitate studies in canine cancer and report here phenotypic and genotypic data associated with these cells.

Role of tissue factor expression in thrombin generation by canine tumor cells.

To measure thrombin generation by high and low tissue factor (TF)-expressing canine cancer cell lines. Canine cell lines CMT25 (high TF-expressing mammary gland tumor cell line) and HMPOS (low TF-expressing osteosarcoma cell line). Thrombin generation by cancer cells was measured in pooled normal canine plasma by use of calibrated automated thrombography without added trigger reagents. Results were expressed as lag time, time to peak thrombin concentration, peak thrombin concentration, and total thrombin concentration or thrombin generation potential. Corn trypsin inhibitor, hirudin, and annexin V were used to inhibit contact activation, thrombin formation, and phosphatidylserine activity, respectively. Pooled normal human plasma deficient in coagulation factors VII, VIII, IX, X, XI, or XII was used to assess the role of individual coagulation factors on thrombin generation. CMT25 generated significantly more thrombin than did HMPOS (mean ± SD, 3,555 ± 604 nM thrombin•min and 636 ± 440 nM thrombin•min, respectively). Thrombin generation of CMT25 was dependent on factor VII and phosphatidylserine and was independent of contact activation. In contrast, thrombin generation of HMPOS was attributed to contact activation. High TF-expressing canine mammary cancer cells generated thrombin in a plasma milieu in vitro in a factor VII- and phosphatidylserine-dependent manner. These findings support a role for TF in hypercoagulability detected in dogs with mammary gland tumors and potentially for other tumors that strongly express TF.

Gastrin-releasing peptide receptor (GRPr) promotes EMT, growth, and invasion in canine prostate cancer.

The gastrin-releasing peptide receptor (GRPr) is upregulated in early and late-stage human prostate cancer (PCa) and other solid tumors of the mammary gland, lung, head and neck, colon, uterus, ovary, and kidney. However, little is known about its role in prostate cancer. This study examined the effects of a heterologous GRPr agonist, bombesin (BBN), on growth, motility, morphology, gene expression, and tumor phenotype of an osteoblastic canine prostate cancer cell line (Ace-1) in vitro and in vivo. The Ace-1 cells were stably transfected with the human GRPr and tumor cells were grown in vitro and as subcutaneous and intratibial tumors in nude mice. The effect of BBN was measured on cell proliferation, cell migration, tumor growth (using bioluminescence), tumor cell morphology, bone tumor phenotype, and epithelial-mesenchymal transition (EMT) and metastasis gene expression (quantitative RT-PCR). GRPr mRNA expression was measured in primary canine prostate cancers and normal prostate glands. Bombesin (BBN) increased tumor cell proliferation and migration in vitro and tumor growth and invasion in vivo. BBN upregulated epithelial-to-mesenchymal transition (EMT) markers (TWIST, SNAIL, and SLUG mRNA) and downregulated epithelial markers (E-cadherin and β-catenin mRNA), and modified tumor cell morphology to a spindle cell phenotype. Blockade of GRPr upregulated E-cadherin and downregulated VIMENTIN and SNAIL mRNA. BBN altered the in vivo tumor phenotype in bone from an osteoblastic to osteolytic phenotype. Primary canine prostate cancers had increased GRPr mRNA expression compared to normal prostates. These data demonstrated that the GRPr is important in prostate cancer growth and progression and targeting GRPr may be a promising strategy for treatment of prostate cancer. Prostate 76:796-809, 2016. © 2016 Wiley Periodicals, Inc.

A human GRPr-transfected Ace-1 canine prostate cancer model in mice.

A versatile drug screening system was developed to simplify early targeted drug discovery in mice and then translate readily from mice to a dog prostate cancer model that more fully replicates the features of human prostate cancer. We stably transfected human cDNA of the GRPr bombesin (BBN) receptor subtype to canine Ace-1 prostate cancer cells (Ace-1(huGRPr) ). Expression was examined by (125) I-Tyr(4) -BBN competition, calcium stimulation assay, and fluorescent microscopy. A dual tumor nude mouse xenograft model was developed from Ace-1(CMV) (vector transfected Ace-1) and Ace-1(huGRPr) cells. The model was used to explore the in vivo behavior of two new IRDye800-labeled GRPr binding optical imaging agents: 800-G-Abz4-t-BBN, from a GRPr agonist peptide, and 800-G-Abz4-STAT, from a GRPr antagonist peptide, by imaging the tumor mice and dissected organs. Both agents bound Ace-1(huGRPr) and PC-3, a known GRPr-expressing human prostate cancer cell line, with 4-13 nM IC50 against (125) I-Tyr(4) -BBN, but did not bind Ace-1(CMV) cells (vector transfected). Binding was blocked by bombesin. Ca(2+) activation assays demonstrated that Ace-1(huGPRr) expressed biologically active GRPr. Both Ace-1 cell lines grew in the flanks of 100% of the nude mice and formed tumors of ∼0.5 cm diameter in 1 week. In vivo imaging of the mice at 800 nm emission showed GRPr+: GRPr- tumor signal brighter by a factor of two at 24 h post IV administration of 10 nmol of the imaging agents. Blood retention (4-8% ID at 1 h) was greater by a factor >10 and cumulative urine accumulation (28-30% at 4 h) was less by a factor 2 compared to a radioactive analog of the t-BBN containing agent, (177) LuAMBA, probably due to binding to blood albumin, which we confirmed in a mouse serum assay. The dual tumor Ace-1(CMV) /Ace-1(huGRPr) model system provides a rapid test of specific to nonspecific binding of new GRPr avid agents in a model that will extend logically to the known Ace-1 orthotopic canine prostate cancer model. Prostate 76:783-795, 2016. © 2016 Wiley Periodicals, Inc.

Effect of Melatonin in Epithelial Mesenchymal Transition Markers and Invasive Properties of Breast Cancer Stem Cells of Canine and Human Cell Lines.

Cancer stem cells (CSCs) have been associated with metastasis and therapeutic resistance and can be generated via epithelial mesenchymal transition (EMT). Some studies suggest that the hormone melatonin acts in CSCs and may participate in the inhibition of the EMT. The objectives of this study were to evaluate the formation of mammospheres from the canine and human breast cancer cell lines, CMT-U229 and MCF-7, and the effects of melatonin treatment on the modulation of stem cell and EMT molecular markers: OCT4, E-cadherin, N-cadherin and vimentin, as well as on cell viability and invasiveness of the cells from mammospheres. The CMT-U229 and MCF-7 cell lines were subjected to three-dimensional culture in special medium for stem cells. The phenotype of mammospheres was first evaluated by flow cytometry (CD44+/CD24low/- marking). Cell viability was measured by MTT colorimetric assay and the expression of the proteins OCT4, E-cadherin, N-cadherin and vimentin was evaluated by immunofluorescence and quantified by optical densitometry. The analysis of cell migration and invasion was performed in Boyden Chamber. Flow cytometry proved the stem cell phenotype with CD44+/CD24low/- positive marking for both cell lines. Cell viability of CMT-U229 and MCF-7 cells was reduced after treatment with 1mM melatonin for 24 h (P<0.05). Immunofluorescence staining showed increased E-cadherin expression (P<0.05) and decreased expression of OCT4, N-cadherin and vimentin (P<0.05) in both cell lines after treatment with 1 mM melatonin for 24 hours. Moreover, treatment with melatonin was able to reduce cell migration and invasion in both cell lines when compared to control group (P<0.05). Our results demonstrate that melatonin shows an inhibitory role in the viability and invasiveness of breast cancer mammospheres as well as in modulating the expression of proteins related to EMT in breast CSCs, suggesting its potential anti-metastatic role in canine and human breast cancer cell lines.

Intra- and interspecies gene expression models for predicting drug response in canine osteosarcoma.

BackgroundGenomics-based predictors of drug response have the potential to improve outcomes associated with cancer therapy. Osteosarcoma (OS), the most common primary bone cancer in dogs, is commonly treated with adjuvant doxorubicin or carboplatin following amputation of the affected limb. We evaluated the use of gene-expression based models built in an intra- or interspecies manner to predict chemosensitivity and treatment outcome in canine OS. Models were built and evaluated using microarray gene expression and drug sensitivity data from human and canine cancer cell lines, and canine OS tumor datasets. The “COXEN” method was utilized to filter gene signatures between human and dog datasets based on strong co-expression patterns. Models were built using linear discriminant analysis via the misclassification penalized posterior algorithm.ResultsThe best doxorubicin model involved genes identified in human lines that were co-expressed and trained on canine OS tumor data, which accurately predicted clinical outcome in 73 % of dogs (p = 0.0262, binomial). The best carboplatin model utilized canine lines for gene identification and model training, with canine OS tumor data for co-expression. Dogs whose treatment matched our predictions had significantly better clinical outcomes than those that didn’t (p = 0.0006, Log Rank), and this predictor significantly associated with longer disease free intervals in a Cox multivariate analysis (hazard ratio = 0.3102, p = 0.0124).ConclusionsOur data show that intra- and interspecies gene expression models can successfully predict response in canine OS, which may improve outcome in dogs and serve as pre-clinical validation for similar methods in human cancer research.Electronic supplementary materialThe online version of this article (doi:10.1186/s12859-016-0942-8) contains supplementary material, which is available to authorized users.

The canine prostate cancer cell line CHP-1 shows over-expression of the co-chaperone small glutamine-rich tetratricopeptide repeat-containing protein α.

Although androgen therapy resistance and poor clinical outcomes are seen in most canine prostate cancer cases, there are only a few tools for analysing canine prostate cancer by using a cell biological approach. Therefore, to evaluate androgen-independent neoplastic cell growth, a new canine prostate cancer cell line (CHP-1) was established in this study. CHP-1 over-expressed the co-chaperone small glutamine-rich tetratricopeptide repeat-containing protein α (SGTA), which is over-expressed in human androgen-independent prostate cancer. The CHP-1 xenograft also showed SGTA over-expression. Although CHP-1 shows poor androgen receptor (AR) signalling upon dihydrotestosterone stimulation, forced expression of AR enabled evaluation of AR signalling. Taken together, these results suggest that CHP-1 will be a useful model for investigating the pathogenesis of androgen-dependent and androgen-independent canine prostate cancer.

Serum starvation and thymidine double blocking achieved efficient cell cycle synchronization and altered the expression of p27, p53, bcl-2 in canine breast cancer cells

Cell synchronization is an approach to obtain cell populations of the same stage, which is a prerequisite to studying the regulation of cell cycle progression in vivo. Serum starvation and thymidine double blocking (TdR) are two important practices in studying cell cycle synchronization. However, their effects on canine cancer cells as well as the regulatory mechanisms by these two methods are poorly understood. In this study, we determined the optimum conditions of serum starvation and TdR and their effects on cell cycle synchronization. We further explored the involvement of PI3K/Akt signaling pathway in the cell cycle synchronization by investigating the expression of three key genes (p27, p53 and bcl-2). Serum starvation resulted in a reversible cell cycle arrest and synchronously progress through G0/G1. The highest percentage of CHMm cells (87.47%) in G0/G1 stage was obtained after 42h incubation with 0.5% fetal bovine serum (FBS). TdR double blocking could arrest 98.9% of CHMm cells in G1/S phase (0h of release), and could arrest 93.74% of CHMm cells in S phase after 4h of release. We also found that the p27, p53, bcl-2 genes were most highly expressed in G0/G1 phase. Our current work revealed that serum starvation and TdR methods could achieve sufficient synchronization of CHMm cells. Moreover, the expression of p27, p53 and bcl-2 genes was related to cyclical movements and apoptosis. Our results will provide a new insight into cell cycle regulation and reprogramming of canine cancer cells induced by serum starvation and TdR blocking.

Hematoporphyrin monomethyl ether combined with He–Ne laser irradiation-induced apoptosis in canine breast cancer cells through the mitochondrial pathway

Hematoporphyrin monomethyl ether (HMME) combined with He-Ne laser irradiation is a novel and promising photodynamic therapy (PDT)-induced apoptosis that can be applied in vitro on canine breast cancer cells. However, the exact pathway responsible for HMME-PDT in canine breast cancer cells remains unknown. CHMm cells morphology and apoptosis were analyzed using optical microscope, terminal deoxynucleotidyl transferase dUTP nick end labeling fluorescein staining and DNA ladder assays. Apoptotic pathway was further confirmed by Real-time-polymerase chain reaction and Western blotting assays. Our results showed that HMME-PDT induced significant changes in cell morphology, such as formation of cytoplasmic vacuoles and the gradual rounding of cells coupled with decreased size and detachment. DNA fragmentation and cell death was shown to occur in a time-dependent manner. Furthermore, HMME-PDT increased the activities of caspase-9 and caspase-3, and released cytochrome c from mitochondria into the cytoplasm. HMME-PDT also significantly increased both mRNA and protein levels of Bax and decreased P53 gene expression in a time-dependent manner, while the mRNA and protein expression of Bcl-2 were repressed. These alterations suggest that HMME-PDT induced CHMm cell apoptosis via the mitochondrial apoptosis pathway and had anti-canine breast cancer effects in vitro.

In vitro comparative models for canine and human breast cancers.

During the past four decades, an increased number of similarities between canine mammary tumors and human breast cancer have been reported: molecular, histological, morphological, clinical and epidemiological, which lead to comparative oncological studies. One of the most important goals in human and veterinary oncology is to discover potential molecular biomarkers that could detect breast cancer in an early stage and to develop new effective therapies. Recently, cancer cell lines have successfully been used as an in vitro model to study the biology of cancer, to investigate molecular pathways and to test the efficiency of anticancer drugs. Moreover, establishment of an experimental animal model for the study of human breast cancer will improve testing potential anti-cancer therapies and the discovery of effective therapeutic schemes suitable for human clinical trials.In this review, we collected data from previous studies that strengthen the value of canine mammary cancer cell lines as an in vitro model for the study of human breast cancer.

Clinical Effects of a Plant Extract Mixture Containing &amp;lt;i&amp;gt;Rhus verniciflua&amp;lt;/i&amp;gt; and Other Herbs in Tumor Bearing Dogs

Dog owners are increasingly seeking treatment when their pets develop cancers. As in human cancer patients, dogs with cancer are commonly treated with complementary and alternative therapies, including herbal medicines and nutritional supplements. A novel antitumor agent was developed from six different herbs including Rhus verniciflua (Rv-PEM01). The components were established from traditional herbal medicine and designed to affect antitumor activity and maintain host immune function. Previous studies identified anti-proliferative activity in human, murine and canine cancer cell lines. In this clinical study the safety and tolerability of Rv-PEM01 were evaluated in pet dogs with spontaneously occurring cancers. Twelve dogs were treated orally daily for 30 days in escalating dose (4 - 10 mg/kg orally once daily) cohorts. Rv-PEM01 was well tolerated; only transient mild elevations in BUN were observed in 2 dogs. Although tumor response was not a primary endpoint for this study, stable disease was maintained for 30 days in 5 (42%) of the dogs. In conclusion, Rv-PEM01 was found to be safe and well tolerated in the dosage range tested. Future studies should evaluate higher dosages of Rv-PEM01 in dogs with cancer, and specifically address other potential benefits of Rv-PEM01 in canine cancer patients, including correlative assessments of immune function, quality of life and owner satisfaction.

The dog prostate cancer (DPC-1) model: a reliable tool for molecular imaging of prostate tumors and metastases.

BackgroundClinical applicability of newly discovered reagents for molecular imaging is hampered by the lack of translational models. As the dog prostate cancer (DPC-1) model recapitulates in dogs the natural history of prostate cancer in man, we tested the feasibility of single-photon emission computed tomography (SPECT)/CT imaging in this model using an anti-prostate-specific membrane antigen (PSMA)/17G1 antibody as the radiotracer.MethodsImmunoblots and immunohistochemistry (IHC) with 17G1 were performed on canine and human prostate cancer cell lines and tissues. Five dogs with DPC-1 tumors were enrolled for pelvic and, in some instances, thoracic SPECT/CT procedures, also repeated over time. Controls included 111indium (In)-17G1 prior to DPC-1 implantation and 111In-immunoglobulins (IgGs) prior to imaging with 111In-17G1 in dogs bearing prostatic DPC-1 tumors.Results17G1 cross-reactivity with canine PSMA (and J591) was confirmed by protein analyses on DPC-1, LNCaP, and PC-3 cell lines and IHC of dog vs. human prostate tissue sections. 17G1 stained luminal cells and DPC-1 cancer cells in dog prostates similarly to human luminal and cancer cells of patients and LNCaP xenografts. SPECT/CT imaging revealed low uptake (≤2.1) of both 111In-17G1 in normal dog prostates and 111In-IgGs in growing DPC-1 prostate tumors comparatively to 111In-17G1 uptake of 3.6 increasing up to 6.5 values in prostate with DPC-1 lesions. Images showed a diffused pattern and, occasionally, a peripheral doughnut-shape-like pattern. Numerous sacro-iliac lymph nodes and lung lesions were detected with contrast ratios of 5.2 and 3.0, respectively. The highest values were observed in pelvic bones (11 and 19) of two dogs, next confirmed as PSMA-positive metastases.ConclusionsThis proof-of-concept PSMA-based SPECT/CT molecular imaging detecting primary prostate tumors and metastases in canines with high cancer burden speaks in favor of this large model’s utility to facilitate technology transfer to the clinic and accelerate applications of new tools and modalities for tumor staging in patients.Electronic supplementary materialThe online version of this article (doi:10.1186/s13550-015-0155-6) contains supplementary material, which is available to authorized users.

Human Genetic Relevance and Potent Antitumor Activity of Heat Shock Protein 90 Inhibition in Canine Lung Adenocarcinoma Cell Lines.

BackgroundIt has been an open question how similar human and canine lung cancers are. This has major implications in availability of human treatments for dogs and in establishing translational models to test new therapies in pet dogs. The prognosis for canine advanced lung cancer is poor and new treatments are needed. Heat shock protein 90 (HSP90) is an ATPase-dependent molecular chaperone ubiquitously expressed in eukaryotic cells. HSP90 is essential for posttranslational conformational maturation and stability of client proteins including protein kinases and transcription factors, many of which are important for the proliferation and survival of cancer cells. We investigated the activity of STA-1474, a HSP90 inhibitor, in two canine lung cancer cell lines, BACA and CLAC.ResultsComparative genomic hybridization analysis of both cell lines revealed genetic relevance to human non-small cell lung cancer. STA-1474 inhibited growth and induced apoptosis of both cell lines in a dose- and time-dependent manner. The ICs50 after 72 h treatment with STA-1474 were 0.08 and 0.11 μM for BACA and CLAC, respectively. When grown as spheroids, the IC50 of STA-1474 for BACA cells was approximately two-fold higher than when grown as a monolayer (0.348 μM vs. 0.168 μM), whereas CLAC spheroids were relatively drug resistant. Treatment of tumor-stromal fibroblasts with STA-1474 resulted in a dose-dependent decrease in their relative cell viability with a low IC50 of 0.28 μM.ConclusionsHere we first established that lung adenocarcinoma in people and dogs are genetically and biochemically similar. STA1474 demonstrated biological activity in both canine lung cancer cell lines and tumor-stromal fibroblasts. As significant decreases in relative cell viability can be achieved with nanomolar concentrations of STA-1474, investigation into the clinical efficacy of this drug in canine lung cancer patients is warranted.

Activity of the DNA minor groove cross-linking agent SG2000 (SJG-136) against canine tumours

BackgroundCancer is the leading cause of death in older dogs and its prevalence is increasing. There is clearly a need to develop more effective anti-cancer drugs in dogs. SG2000 (SJG-136) is a sequence selective DNA minor groove cross-linking agent. Based on its in vitro potency, the spectrum of in vivo and clinical activity against human tumours, and its tolerability in human patients, SG2000 has potential as a novel therapeutic against spontaneously occurring canine malignancies.ResultsIn vitro cytotoxicity was assessed using SRB and MTT assays, and in vivo activity was assessed using canine tumour xenografts. DNA interstrand cross-linking (ICL) was determined using a modification of the single cell gel electrophoresis (comet) assay. Effects on cell cycle distribution were assessed by flow cytometry and measurement of γ-H2AX by immunofluorescence and immunohistochemistry.SG2000 had a multi-log differential cytotoxic profile against a panel of 12 canine tumour cell lines representing a range of common tumour types in dogs. In the CMeC-1 melanoma cell line, DNA ICLs increased linearly with dose following a 1 h treatment. Peak ICL was achieved within 1 h and no removal was observed over 48 h. A relationship between DNA ICL formation and cytotoxicity was observed across cell lines. The formation of γ-H2AX foci was slow, becoming evident after 4 h and reaching a peak at 24 h.SG2000 exhibited significant anti-tumour activity against two canine melanoma tumour models in vivo. Anti-tumour activity was observed at 0.15 and 0.3 mg/kg given i.v. either once, or weekly x 3. Dose-dependent DNA ICL was observed in tumours (and to a lower level in peripheral blood mononuclear cells) at 2 h and persisted at 24 h. ICL increased following the second and third doses in a repeated dose schedule. At 24 h, dose dependent γ-H2AX foci were more numerous than at 2 h, and greater in tumours than in peripheral blood mononuclear cells. SG2000-induced H2AX phosphorylation measured by immunohistochemistry showed good correspondence, but less sensitivity, than measurement of foci.ConclusionsSG2000 displayed potent activity in vitro against canine cancer cell lines as a result of the formation and persistence of DNA ICLs. SG2000 also had significant in vivo antitumour activity against canine melanoma xenografts, and the comet and γ-H2AX foci methods were relevant pharmacodynamic assays. The clinical testing of SG2000 against spontaneous canine cancer is warranted.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-015-0534-2) contains supplementary material, which is available to authorized users.

Molecular cloning of canine co-chaperone small glutamine-rich tetratricopeptide repeat-containing protein α (SGTA) and investigation of its ability to suppress androgen receptor signalling in androgen-independent prostate cancer

Although the morbidity of canine prostate cancer is low, the majority of cases present with resistance to androgen therapy and poor clinical outcomes. These pathological conditions are similar to the signs of the terminal stage of human androgen-independent prostate cancer. The co-chaperone small glutamine-rich tetratricopeptide repeat-containing protein α (SGTA) is known to be overexpressed in human androgen-independent prostate cancer. However, there is little information about the structure and function of canine SGTA. In this study, canine SGTA was cloned and analysed for its ability to suppress androgen receptor signalling.The full-length open reading frame (ORF) of the canine SGTA gene was amplified by RT-PCR using primers designed from canine-expressed sequence tags that were homologous to human SGTA. The canine SGTA ORF has high homology with the corresponding human (89%) and mouse (81%) sequences. SGTA dimerisation region and tetratricopeptide repeat (TPR) domains are conserved across the three species. The ability of canine SGTA to undergo homodimerisation was demonstrated by a mammalian two-hybrid system and a pull-down assay. The negative impact of canine SGTA on androgen receptor (AR) signalling was demonstrated using a reporter assay in androgen-independent human prostate cancer cell lines. Pathological analysis showed overexpression of SGTA in canine prostate cancer, but not in hyperplasia. A reporter assay in prostate cells demonstrated suppression of AR signalling by canine SGTA. Altogether, these results suggest that canine SGTA may play an important role in the acquisition of androgen independence by canine prostate cancer cells.

Abstract 5142: A naturally occurring model for gastric cancer

Abstract Gastric cancer is the fourth most common cancer and the second leading cause of cancer related deaths. While there are increasing data characterizing the molecular features and defining potential targets for gastric carcinoma, preclinical animal models that recapitulate the human disease are limited. We have developed a number of resources to permit the characterization of spontaneously occurring canine gastric cancer which may provide a useful resource to understand gastric cancer carcinogenesis, its prevention and treatment. While gastric carcinoma is reportedly uncommon in dogs, certain breeds have significantly increased risk. To study this disease, we have established a database and tissue repository. Our goal has been to characterize canine gastric carcinoma clinically, histologically, and molecularly to determine its comparative value as a model for the human disease. Recently, we have performed a histologic review of 50 canine gastric carcinomas and have found that the canine disease is comprises largely of diffuse type gastric carcinoma and is enriched in the signet ring variant. We report for the first time a technique for culturing primary gastric cancer from affected dogs. Gastric cancer tissue specimens collected from spontaneously occurring tumors in dogs were disaggregated with collagenase and cells were grown in mammary epithelial growth media with or without 5% FBS. Four different cell lines were derived from tumors of a Labrador mix (GC1), a Basset hound (GC2), a Bouvier de Flandres (GC3) and a mixed breed (GC4). Early passages of all cell lines were able to form colonies when grown in soft agar. Different growth patterns were observed when cells were cultured with versus without serum. Serum treated cells tend to be fast growing, fibroblastic in appearance and senesce within 10 to 18 passages and these may represent cancer associated fibroblasts or mesenchymal differentiation of cancer cells. However, cells grown in mammary epithelial growth media without serum tend to form spheres that grow well when transferred to ultra-low attachment plate and form extensions when grown in matrigel. That semi-attached growth behavior is consistent with that reported for some human gastric cancer cell lines. Canine gastric cancer cell lines provide a new resource for the characterization of this spontaneous model that recapitulates diffuse, signet ring cell gastric carcinoma. Citation Format: Manar A. AbdelMageed, Monica Betancur-Boissel, Parthena Foltopoulou, Sureshkumar Muthupalani, James G. Fox, Elizabeth A. McNiel. A naturally occurring model for gastric cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5142. doi:10.1158/1538-7445.AM2015-5142

Abstract 5136: The Flint Animal Cancer Center (FACC) canine tumor cell line panel: A resource for comparative and translational oncology

Abstract Purpose: Mammalian cell tissue culture has been a critical tool leading to our current understanding of cancer including many aspects of cellular transformation, growth, and response to therapies. The current use of large panels of human cancer cell lines (i.e. NCI60, GDSC) with associated phenotypic and genotypic information allows for informatics approaches and in silico screens to rapidly test hypotheses based on simple as well as complex relationships. We have assembled a panel of canine cancer cell lines to facilitate translational studies in canine cancer and report here the characteristics and some applications of this panel in comparative oncology. Methods: Canine cancer cell lines isolated from tumors have been accumulated from a number of sources over the years. Our current panel consists of 29 cell lines that have been validated as being of canine origin and “fingerprinted” by microsatellite analysis. The tumor types represented include 10 osteosarcomas, 5 melanomas, 2 mammary carcinomas, 1 hemangiosarcoma, 2 bladder carcinomas, 4 lymphoma/leukemias, 1 mast cell tumor, 2 histiocytic sarcomas, 1 thyroid carcinoma and 1 soft-tissue sarcoma. Drug sensitivity analysis was carried out using a resazurin-based bioreductive fluorometric assay. Gene expression microarray analysis was carried out using the Affymetrix GeneChip Canine 2.0 at the Genomics and Microarray Core (University of Colorado Cancer Center). Results: Drug sensitivity to the cytotoxic chemotherapeutic agents carboplatin, cisplatin, doxorubicin, lomustine, paclitaxel and vinblastine were assessed and compared to responses in the human NCI-60 panel. Results show that the human and canine cell lines show similar ranges of sensitivity to these agents. The mean GI50 values for the human and canine cell lines are significantly different for DOX, VBL, CARBO, CCNU as well as PTX. The variances in the data were also significantly different for CARBO and PTX. Overall, however, the drug sensitivity/resistance patterns in the canine and human tumor cell line panels shared general trends with regard to sensitivity and variance observed to the specific agents with the mean Log GI50 values for each agent showing a cross-species correlation (r = 0.88, p = 0.0194, Pearson). Cluster analysis of the gene expression data using the top 100 most variant genes as well as the 100 top most variant cancer genes largely separates the panel into groups with similar histiotypes. Cluster analysis of cancer genes also highlights alterations in gene expression that may contribute to pathogenesis in some cell lines such as loss of the PTEN tumor suppressor or elevated expression of receptor tyrosine kinase genes. Conclusions: The FACC canine tumor cell line panel represents a validated panel of representative cancers from dogs that can be utilized for comparative oncology studies as well as applications in drug development where use of a companion animal model is appropriate. Citation Format: Daniel L. Gustafson, Jared S. Fowles, Douglas H. Thamm, Rodney L. Page, Dawn L. Duval. The Flint Animal Cancer Center (FACC) canine tumor cell line panel: A resource for comparative and translational oncology. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5136. doi:10.1158/1538-7445.AM2015-5136

Attenuated Semliki Forest virus for cancer treatment in dogs: safety assessment in two laboratory Beagles.

BackgroundDogs suffer from spontaneous tumors which may be amenable to therapies developed for human cancer patients, and dogs may serve as large-animal cancer models. A non-pathogenic Semliki Forest virus vector VA7-EGFP previously showed promise in targeting human tumor xenografts in mice, but the oncolytic capacity of the virus in canine cancer cells and the safety of the virus in higher mammals such as dogs, are not known. We therefore assessed the oncolytic potency of VA7-EGFP against canine cancer cells by infectivity and viability assays in two dog solid tumor cell lines. Furthermore we performed a 3-week safety study in two adult Beagles which received a single intravenous injection of ~2 × 105 plaque forming units of parental A7(74) strain.ResultsVA7-EGFP was able to replicate in and kill both canine cancer cell lines tested. No adverse events were observed in either of the two virus-injected adult Beagles and no infective virus could be recovered from any of the biological samples collected over the course of the study. Neutralizing antibodies to Semliki Forest virus became detectable in the dogs at 5 days post infection and remained elevated until study termination.ConclusionsBased on these results, testing of the oncolytic potential of attenuated Semliki Forest virus in canine cancer patients appears feasible.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-015-0498-2) contains supplementary material, which is available to authorized users.