Canine Thyroid Cancer: Molecular Characterization and Cell Line Growth in Nude Mice.

Thyroid cancer is the most common endocrine malignancy in dogs. Dogs and humans are similar in the spontaneous development of thyroid cancer and metastasis to lungs; however, thyroid cancer has a higher incidence of metastasis in dogs. This study developed a preclinical nude mouse model of canine thyroid cancer using a canine thyroid adenocarcinoma cell line (CTAC) and measured the expression of important invasion and metastasis genes in spontaneous canine thyroid carcinomas and CTAC cells. CTAC cells were examined by electron microscopy. Short tandem repeat analysis was performed for both the original neoplasm and CTAC cells. CTAC cells were transduced with luciferase and injected subcutaneously and into the tail vein. Tumors and metastases were monitored using bioluminescent imaging and confirmed with gross necropsy and histopathology. Invasion and metastasis genes were characterized in 8 follicular thyroid carcinomas (FTCs), 4 C-cell thyroid carcinomas, 3 normal thyroids, and CTAC cells. CTAC cells grew well as xenografts in the subcutis, and they resembled the primary neoplasm. Metastasis to the kidney and lung occurred infrequently following subcutaneous and tail vein injection of CTAC cells. STR analysis confirmed that CTAC cells were derived from the original neoplasm and were of canine origin. Finally, 24 genes were differentially expressed in spontaneous canine thyroid carcinomas, CTAC, and normal thyroids. This study demonstrated the usefulness of a nude mouse model of experimental canine thyroid carcinoma and identified potential molecular targets of canine follicular and C-cell thyroid carcinoma.

A Transplantable Syngeneic Allograft Mouse Model for Nongestational Choriocarcinoma of the Ovary.

Nongestational choriocarcinoma is a rare malignancy in humans with poor prognosis. Naturally occurring choriocarcinoma is also rare in laboratory mice, and no genetic mouse model accurately recapitulates the features of this cancer. Here we report development of a genetically engineered mouse (GEM) model with alterations in Brca2, Trp53, and RB that develops ovarian tumors. Most of the ovarian tumors displayed histological characteristics of nongestational choriocarcinoma of the ovary (NGCO) (47%) with abundant syncytiotrophoblasts and cytotrophoblasts, positive immunolabeling for human chorionic gonadotropin, and positive periodic acid-Schiff reaction. The rest of the ovarian tumors were serous epithelial ovarian carcinoma (SEOC) (26%) or mixed tumors consisting of NGCO and SEOC (26%). We further established syngeneic orthotopic mouse models for NGCO by in vivo passaging of GEM tumors. These metastatic models provide a platform for evaluating new treatment strategies in preclinical studies aimed at improving outcomes in choriocarcinoma patients.

Comparison of hock- and footpad-injection as a prostate adenocarcinoma model in rats.

BACKGROUND: Objective of this study is a feasibility-test comparing hock- and footpad-injection in rats with inoculated MatLyLu - adenocarcinoma tumor model. This study compares the development of an adenocarcinoma model (MatLyLu) in 12 Copenhagen rats. Two groups (n = 6) of animals were inoculated with 1 × 106 MatLyLu tumor cells solved in 0.1 ml NaCl either by footpad or hock injection. All animals were examined before tumor inoculation and before euthanasia using a 3.0 Tesla MRI. Histological evaluation of all organs was performed post mortem. RESULTS: Both types of injection were able to induce the adenocarcinoma model using MatLyLu tumor cells. The primary tumor could be visualized in MRI and confirmed histologically. Comparing the risk of reflux and the maximum injection volume during injection, the hock injection was superior to the footpad injection (less reflux, less anatomical restrictions for larger volumes). The hock injection induces a faster tumor growth compared to the footpad injection. As consequence the maximum level of long term discomfort after hock injection was reached earlier, even if it grew on a not weight bearing structure. Early lymph node tumor metastasis could not be observed macroscopically nor detected histologically. Therefore the reproducibility of the MatLyLu tumor model is questionable. CONCLUSION: Hock injection is a feasible alternative technique compared with footpad-injection in rats. It provides a save and easy injection method for various early-terminated applications with the potential to increase animal welfare during tumor models in rats.

Anti-tumour effect of lapatinib in canine transitional cell carcinoma cell lines.

Transitional cell carcinoma (TCC) accounts for >90% of canine malignant tumours occurring in urinary bladder, and the prognosis is poor. Our previous study, using RNA sequencing, showed that human epidermal growth factor 2 (HER2) was the most activated upstream regulator related to carcinogenesis in canine TCC. The aim of this study was to examine the anti-tumour effect of lapatinib, a tyrosine kinase inhibitor of HER2, on canine TCC cell lines in vitro and in vivo. Five canine TCC cell lines (TCCUB, Love, Sora, LCTCC, and MCTCC) were used. Western blotting showed that HER2 protein expression was observed in all of the canine TCC cell lines. Lapatinib inhibited phosphorylation of HER2 and cell growth in a dose-dependent manner. Cell cycle analyses using flow cytometry showed that lapatinib significantly increased the sub-G1 and G0 /G1 phase fractions and significantly decreased the S and G2 /M phase fractions in the cell lines (Sora and TCCUB). For the in vivo experiments, the canine TCC cells (Sora) were subcutaneously injected into nude mice. Six days after inoculation, lapatinib (100 mg/kg) or vehicle was administered daily via intraperitoneal administration for 14 days. Tumour volume was significantly smaller in the lapatinib group compared with the vehicle control group. Histologically, lapatinib significantly increased necrotic areas in the tumour tissues. These findings suggest that lapatinib exerts anti-tumour effects on canine TCC cells by inhibiting HER2 signalling and inducing cell cycle arrest.

Targeting NEDD8-activating enzyme is a new approach to treat canine diffuse large B-cell lymphoma.

Canine diffuse large B-cell lymphoma (DLBCL), the most common hematologic malignancy of dogs, is associated with poor overall survival. The lack of conventional chemotherapies with sustainable efficacy warrants investigation of novel therapies. Pevonedistat (MLN4924) is a potent and selective small molecule NEDD8-activating enzyme inhibitor. In human activated B-cell-like (ABC) diffuse large B-cell lymphoma, pevonedistat induces lymphoma cell apoptosis, DNA damage and G1 cell cycle arrest by inhibiting the nuclear factor-κB (NF-κB) pathway. Genomic and transcriptomic studies showed that the NF-κB pathway is deregulated in canine DLBCL. Our results showed that pevonedistat treatment significantly reduces the viability of canine DLBCL cells by inducing G1 cell cycle arrest and apoptosis. Pevonedistat treatment inhibits NF-κB pathway activation and downregulates NF-κB target genes in canine DLBCL. Moreover, administration of pevonedistat to mice bearing canine DLBCL xenograft tumours resulted in tumour regression. Our in vivo and in vitro studies provide justification for future clinical application of pevonedistat as a potential new anti-cancer therapy that may benefit both canine and human species.

Phenotypic analysis of mice xenografted with canine epitheliotropic cutaneous T-cell lymphoma cells.

BACKGROUND: In canine epitheliotropic cutaneous T-cell lymphoma (ECTCL), neoplastic cells cause skin lesions and potentially metastasize to lymph nodes, blood and other organs. Murine models are potentially valuable for elucidating the molecular mechanisms responsible for regulation of ECTCL cell migration. HYPOTHESIS/OBJECTIVES: To describe a phenotype of mice xenografted with canine ECTCL cells (EO-1 cells). ANIMALS: Four NOD.CB17-Prkdcscid /J (NOD SCID) mice were used. METHODS AND MATERIALS: EO-1 cells were subcutaneously xenografted into NOD SCID mice. After four weeks, the development of tumour lesions in skin and other organs was investigated. RESULTS: Mice developed skin lesions with metastasis to the lymph nodes, spleen, lung, blood and liver. CONCLUSIONS AND CLINICAL IMPORTANCE: Mice xenografted with EO-1 cells may be useful for studying the pathogenesis of canine ECTCL.

Effectiveness of CO2 laser in an experimental mammary gland adenocarcinoma model.

BACKGROUND: The important goal of modern research in the field of surgical oncology is the quest for a tool that could improve the outcomes of tumour excision. AIMS: The aim of this study was to compare the usefulness of the CO2 laser with flexible hollow waveguide and scalpel in mammary tumour excision. MATERIALS & METHODS: A total of 112 female BALB/c mice with implanted orthotopically 4T1-luc2-tdTomato tumour cells were included in the research. Tumours were excised in 48 mice using the CO2 laser and in 48 through scalpel surgery. The control group consisted of 16 untreated mice. The evaluation of surgical outcome was obtained by in vivo bioluminescence and fluorescence imaging and post-mortem histopathological examination. RESULTS: There were no significant differences between recurrence rates, metastases and survival time in groups excised with the scalpel and CO2 laser. CONCLUSION: The CO2 laser has similar efficacy compared with conventional scalpel excision for local recurrence rates, incidence of distant metastases and survival time and can be safely applied in oncological surgery.

Effect of dasatinib in a xenograft mouse model of canine histiocytic sarcoma and in vitro expression status of its potential target EPHA2.

Canine histiocytic sarcoma (HS) is an aggressive and highly metastatic tumor. Previously, the kinase inhibitor dasatinib was shown to have potent growth inhibitory activity against HS cells in vitro, possibly via targeting the EPHA2 receptor. Here, the in vivo effect of dasatinib in HS cells was investigated using a xenograft mouse model. Moreover, the expression status of EPHA2 was examined in six HS cell lines, ranging from insensitive to highly sensitive to dasatinib. In the HS xenograft mouse model, dasatinib significantly suppressed tumor growth, as illustrated by a decrease in mitotic and Ki67 indices and an increase in apoptotic index in tumor tissues. On Western blot analysis, EPHA2 was only weakly detected in all HS cell lines, regardless of sensitivity to dasatinib. Dasatinib likely results in the inhibition of xenograft tumor growth via a mechanism other than targeting EPHA2. The findings of this study suggest that dasatinib is a targeted therapy drug worthy of further exploration for the treatment of canine HS.

Establishment and characterization of a canine soft tissue sarcoma patient-derived xenograft model.

Spontaneously occurring soft tissue sarcoma (STS) is relatively common in canine cancer patients. Because of the similarities to human disease, canine STSs are a valuable and readily available resource for the study of new therapeutics. In this study, a canine patient-derived xenograft (PDX) model, CDX-STS2, was established. The CDX-STS2 model was engrafted and expanded for systemic administration studies with chemotherapeutic agents commonly used to treat STS, including doxorubicin, docetaxel and gemcitabine. Immunohistochemistry for drug-specific biomarkers and tumour growth measurement revealed tumour sensitivity to doxorubicin and docetaxel, whereas gemcitabine had no effect on tumour growth. Although many human PDX tumour models have been established, relatively few canine PDX models have been reported to date. CDX-STS2 represents a new STS PDX research model of canine origin that will be useful in bridging preclinical research with clinical studies of STS in pet dogs.

A novel canine B-cell leukaemia cell line. Establishment, characterisation and sensitivity to chemotherapeutics.

We established a new B-cell leukaemia cell line CLB70 from a dog with chronic lymphocytic leukaemia. This cell line is positive for CD20, CD45, CD79a, MHC class II, IgG, IgM; weakly positive for CD21; and negative for CD3, CD4, CD5, CD8, CD14, CD34, CD117. PCR for antigen receptor gene rearrangement (PARR) analysis revealed a biclonal immunoglobulin heavy chain (IgH) gene rearrangement and negative result for TCRγ. Western blot analysis of anti- and pro-apoptotic proteins showed increased expression of Bcl-2, Mcl-1, NF-kB, and Ras, and decreased expression of p53. CLB70 cells grow rapidly in vitro and are tumourigenic in nude mice. The CLB70 line is highly sensitive to doxorubicin, less sensitive to etoposide and imatinib, and resistant to piroxicam, celecoxib and dexamethasone. Our results indicate that CLB70 cells are derived from mature B-cells and they may be a useful tool for the development of new therapeutic strategies for both dogs and humans.

Establishment and characterization of a canine xenograft model of inflammatory mammary carcinoma.

Canine inflammatory mammary cancer (IMC) and human inflammatory breast cancer (IBC) are the most aggressive form of mammary/breast cancer. Both species naturally develop it, sharing epidemiological, clinical and histological characteristics. Thus, IMC has been suggested as a model to study the human disease. We have developed the first IMC xenograft model in SCID mice. Xenografts reproduced the histological features from the primary tumor, were highly aggressive and showed dermal tumor emboli, distinctive hallmarks of IMC/IBC. This model was hormone receptors positive and HER2 negative. Our findings showed that estrogens and androgens are locally produced in tissues. Factors related to tumor vascularization showed positive expression and xenografts with the highest expression of all analyzed vascular factors had the highest rate of tumor proliferation. The role of steroid hormones and the angio/lymphangiogenic properties found in this model, provide additional knowledge for future interventions in the diagnosis, treatment and prevention of the disease.

Establishment of a pair of novel cloned tumour cell lines with or without metastatic potential from canine mammary adenocarcinoma.

We produced 23 cloned cell lines from parental CHMp, which was previously established from a canine mammary adenocarcinoma patient in our laboratory. Two representative cloned cell lines, namely, CHMp-5b and -13a, were selected and characterized for cellular morphology, growth potential and expression of some tumour-related proteins. Subsequently, we transplanted the 2 tumour cell lines orthotopically into female nude mice to examine their tumorigenicity and metastatic potential. Interestingly, despite sharing the same origin, only CHMp-5b cells metastasized to the lung. Our results indicate that a comparison between these 2 cell lines at the molecular level will help us understand mechanisms of tumour progression, especially in the context of distant metastases originating from canine mammary gland tumours.

A murine xenograft model for a transmissible cancer in Tasmanian devils.

The number of Tasmanian devils in the wild is rapidly declining owing to a transmissible cancer, devil facial tumor disease (DFTD). Although progress has been made to understand the spread of this disease, crucial research on the pathogenesis of DFTD has been limited because of the threatened status of the host species. Here, the authors describe the development of a NOD/SCID (nonobese diabetic / severe combined immunodeficiency) mouse model that reproduces DFTD and provides a much-needed model to undertake studies into this intriguing transmissible cancer. Histologically, the DFTD produced in NOD/SCID mice (xenografted DFTD) was indistinguishable from the DFTD identified in Tasmanian devils. At the protein level, all xenografted DFTD tumors expressed periaxin, a marker that confirmed the diagnosis of DFTD. The karyotype of DFTD in NOD/SCID mice reproduced similar chromosomal alterations as seen in diseased devils. Furthermore, each NOD/SCID mouse inoculated with cultured DFTD tumor cells developed tumors, whereas DFTD did not develop in any of the inoculated immune-competent BALB/c mice.

Interleukin-11 receptor alpha is expressed on canine osteosarcoma.

Osteosarcoma (OSA) is the most common bone tumour in humans and companion animals, and has a poor long-term prognosis. The identification of new markers and targeted therapies may help increase long-term survival of these patients. Previous studies have demonstrated that interleukin-11 receptor alpha (IL-11Ralpha) is expressed in human and murine OSA but not in normal bone. The current study demonstrated via western analysis, immunoflourescence and immunohistochemistry that IL-11Ralpha was expressed in primary canine OSA tissues as well as in a number of canine OSA cell lines, but not in normal canine bone. Cytotoxin-conjugated antibodies targeting IL-11Ralpha-mediated canine OSA cytotoxicity. Thus, canine OSA may be a valuable model for the evaluation of IL-11Ralpha directed therapies.

Targeting monoamine oxidase A in advanced prostate cancer.

PURPOSE: Inhibitors of monoamine oxidase A (MAOA), a mitochondrial enzyme that degrades neurotransmitters including serotonin and norepinephrine, are commonly used to treat neurological conditions including depression. Recently, we and others identified high expression of MAOA in normal basal prostatic epithelium and high-grade primary prostate cancer (PCa). In contrast, MAOA is low in normal secretory prostatic epithelium and low-grade PCa. An irreversible inhibitor of MAOA, clorgyline, induced secretory differentiation in primary cultures of normal basal epithelial cells and high-grade PCa. Furthermore, clorgyline inhibited several oncogenic pathways in PCa cells, suggesting clinical value of MAOA inhibitors as a pro-differentiation and anti-oncogenic therapy for high-risk PCa. Here, we extended our studies to a model of advanced PCa, VCaP cells, which were derived from castration-resistant metastatic PCa and express a high level of MAOA. METHODS: Growth of VCaP cells in the presence or absence of clorgyline was evaluated in vitro and in vivo. Gene expression changes in response to clorgyline were determined by microarray and validated by quantitative real-time polymerase chain reaction. RESULTS: Treatment with clorgyline in vitro inhibited growth and altered the transcriptional pattern of VCaP cells in a manner consistent with the pro-differentiation and anti-oncogenic effects seen in treated primary PCa cells. Src, beta-catenin, and MAPK oncogenic pathways, implicated in androgen-independent growth and metastasis, were significantly downregulated. Clorgyline treatment of mice bearing VCaP xenografts slowed tumor growth and induced transcriptome changes similar to those noted in vitro. CONCLUSION: Our results support the possibility that anti-depressant drugs that target MAOA might find a new application in treating PCa.

The role of the intravascular microenvironment in spontaneous metastasis development.

Metastasis is primarily responsible for the morbidity and mortality of cancer. Improved therapeutic outcomes and prognosis depend on improved understanding of mechanisms regulating the establishment of early metastasis. In this study, use of green fluorescent protein (GFP)-expressing PC-3 orthotopic model of human prostate cancer and two complementary fluorescence in vivo imaging systems (Olympus OV100 and VisEn FMT) allowed for the first time real-time characterization of cancer cell-endothelium interactions during spontaneous metastatic colonization of the liver and lung in live mice. We observed that prior to the detection of extra-vascular metastases, GFP-expressing PC-3 cancer cells resided initially inside the blood vessels of the liver and the lung, where they proliferated and expressed Ki-67 and exhibited matrix metalloprotenases (MMP) activity. Thus, the intravascular cancer cells produced their own microenvironment, where they could continue to proliferate. Extravasation occurred earlier in the lung than in the liver. Our results demonstrate that the intravascular microenvironment is a critical staging area for the development of metastasis that later can invade the parenchyma. Intravascular tumor cells may represent a therapeutic target to inhibit the development of extravascular metastases. Therefore, this imageable model of intravascular metastasis may be used for evaluation of novel anti-metastatic agents.

Evaluation of antitumor activity of peptide extracts from medicinal plants on the model of transplanted breast cancer in CBRB-Rb(8.17)1Iem mice.

We studied antitumor effects of peptide extracts from plants on slowly growing mammary adenocarcinoma in CBRB-Rb(8.17)1Iem mice used as a model of breast cancer in humans. The antitumor effect of a single injection of the test peptides was evaluated by the delay of the appearance and growth of palpable breast cancer in mice over 4 weeks. Peptides from Hypericum perforatum and a mixture of Chelidonium majus L., Inula helenium L., Equisetum arvense L., and Inonotus obliquus exhibited maximum activity. Peptide extracts from Frangula alnuc Mill. and Laurus nobilis L. were less active. No antitumor effect of Camelia sinesis Kuntze was detected.

NOD/SCID mouse model of canine T-cell lymphoma with humoral hypercalcaemia of malignancy: cytokine gene expression profiling and in vivo bioluminescent imaging.

Lymphoma is a malignant neoplasm arising from B or T lymphocytes. In dogs, one-third of lymphomas are highly aggressive multicentric T-cell lymphomas that are often associated with humoral hypercalcaemia of malignancy (HHM). There are no cell lines or animal models to investigate the pathogenesis of T-cell lymphoma and HHM in dogs. We developed the first xenograft model by injecting lymphoma cells from an Irish Wolfhound intraperitoneally into NOD/SCID mice. The mice developed multicentric lymphoma along with HHM and increased parathyroid hormone-related protein (PTHrP) as occurs in dogs with T-cell lymphoma. Using cytokine complementary DNA arrays, we identified genes that have potential implications in the pathogenesis of T-cell lymphoma. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) of T-cell lymphoma samples from hypercalcaemic canine patients showed that PTHrP likely plays a central role in the pathogenesis of HHM and that hypercalcaemia is the result of a combinatorial effect of different hypercalcaemic factors. Finally, we monitored in vivo tumour progression and metastases in the mouse model by transducing the lymphoma cells with a lentiviral vector that encodes a luciferase-yellow fluorescent protein reporter and showed that in vivo trafficking patterns in this model were similar to those seen in dogs. This unique mouse model will be useful for translational research in lymphoma and for investigating the pathogenesis of T-cell lymphoma and HHM in the dog.

Scanning spontaneous photon emission from transplanted ovarian tumor of mice using a photomultiplier tube.

A scanning system for the detection of spontaneous ultraweak photon emission from nude mice with transplanted tumors is presented. A photomultiplier tube (PMT) with an effective area of 15 mm diameter was used for measuring photon emission in a wavelength range from 300 to 650 nm. Tumors were induced in nude mice by transplantation of an ovarian cancer cell line into the back of mice. The PMT was moved for scanning over the whole body of a mouse placed in a dark box. The profiles of the intensities of photon emissions from the tumor mice are presented and compared with those obtained from the control mice.

Cell-free transmission of a haemic neoplasm in the cockle Cerastoderma edule.

A haemic neoplasm occurs in populations of the common cockle Cerastoderma edule L. along the coast of Ireland. The morphology, epizootiology and distribution of the disease have previously been described. The aetiology of the neoplasm is unknown. In this study transmission of the neoplasm between cockles was accomplished using both whole neoplastic cells and neoplastic cell-free homogenates which were filtered through 0.45 microm Millipore filters. Successful transmission of the disease has been achieved by both methods. These results indicate that the neoplasm in cockles may have a viral aetiology. Whole neoplastic cell inoculation resulted in a higher level of disease development compared to that of cell-free inoculates. The survival rates of the inoculated groups were compared and a significant decrease in survival was found in those groups which developed the disease.