Cutaneous mast cell tumours (MCT) are the most common skin tumour in dogs, and to our knowledge, there are no previous studies regarding the global methylation of these tumours. DNA hypomethylation and hypermethylation have been described in several tumours and both mechanisms can lead to carcinogenesis. The purpose of this study was to evaluate the global DNA methylation in canine MCT. A total of 48 MCT samples were classified in grades 1, 2 and 3 or high-grade or low-grade. Monoclonal antibodies were used for the immunohistochemical detection of the 5-methylcytosine. The immunostained nuclei were classified in strong, weak or negative pattern, and these were quantified in five distinct microscopic fields (40× objective) in each slide. The results showed that global DNA hypomethylation was predominant in grade 3, high-grade, less differentiated MCT. These epigenetic changes in neoplastic mast cells warrant further detailed investigation aiming the establishment of tumour epigenetic therapies.

Canine oral mucosal melanomas (OMM) are the most common oral malignancy in dogs and few treatments are available. Thus, new treatment modalities are needed for this disease. Bacillus anthracis (anthrax) toxin has been reengineered to target tumor cells that express urokinase plasminogen activator (uPA) and metalloproteinases (MMP-2), and has shown antineoplastic effects both, in vitro and in vivo. This study aimed to evaluate the effects of a reengineered anthrax toxin on canine OMM. Five dogs bearing OMM without lung metastasis were included in the clinical study. Tumor tissue was analyzed by immunohistochemistry for expression of uPA, uPA receptor, MMP-2, MT1-MMP and TIMP-2. Animals received either three or six intratumoral injections of the reengineered anthrax toxin prior to surgical tumor excision. OMM samples from the five dogs were positive for all antibodies. After intratumoral treatment, all dogs showed stable disease according to the canine Response Evaluation Criteria in Solid Tumors (cRECIST), and tumors had decreased bleeding. Histopathology has shown necrosis of tumor cells and blood vessel walls after treatment. No significant systemic side effects were noted. In conclusion, the reengineered anthrax toxin exerted inhibitory effects when administered intratumorally, and systemic administration of this toxin is a promising therapy for canine OMM.

Euphorbia tirucalli (E. tirucalli) is a tropical and subtropical plant that produces a latex which is used for several purposes. The components of E. tirucalli latex include triterpenes, diterpenes and steroids. The aim of the present study was to evaluate the effects of diluted E. tirucalli latex on murine B16/F10 melanoma cells and lung metastasis. For this purpose, an in vitro study was first performed, in which B16/F10 cells were treated with diluted (1/2 to 1/11,192) E. tirucalli latex. In a second study, B16/F10 melanoma cells were inoculated into the tail vein of mice to generate lung metastases; the mice then received 0.467 µg of latex diluted in 200 ml saline by gavage for 14 days. A significant decrease in B16/F10 cell viability was observed using the MTT assay at 24 and 48 h after treatment with E. tirucalli latex. In addition, a significant decrease in the volume fraction occupied by B16/F10 metastatic colonies in the lungs was observed in mice treated with E. tirucalli latex. These results confirm the antineoplastic effects of diluted E. tirucalli latex.

There are many factors which make canine cancer like cancer in humans. The occurrence of spontaneous mammary tumors in pet dogs, tumor genetics, molecular targets and exposure to the same environmental risk factors are among these factors. Therefore, the study of canine cancer can provide useful information to the oncology field. This study aimed to establish and characterize a panel of primary mixed cell cultures obtained from spontaneous canine mammary tumors. Eight established cell cultures obtained from one normal mammary gland, one complex adenoma, one mixed adenoma, two complex carcinomas and two mixed carcinomas were analyzed. The gene expression levels of classic molecular cancer players such as fibroblast growth factor receptor (FGFR) 2, breast cancer (BRCA) 1, BRCA2 and estrogen receptor (ESR) 1 were evaluated. For the first time, three orphan nuclear receptors, estrogen-related receptors (ERRs) α, β and γ were studied in canine mammary cancer. The highest expression level of ERRα was observed in complex carcinoma-derived cell culture, while the highest levels of ERRβ and γ were observed in cells derived from a mixed carcinoma. Meanwhile, complex carcinomas presented the highest levels of expression of ESR1, BRCA1 and FGFR2 among all samples. BRCA2 was found exclusively in complex adenoma. The transcription factor GATA3 had its highest levels in mixed carcinoma samples and its lowest levels in complex adenoma. Proliferation assays were also performed to evaluate the mixed cell cultures response to ER ligands, genistein and DES, both in normoxia and hypoxic conditions. Our results demonstrate that morphological and functional studies of primary mixed cell cultures derived from spontaneous canine mammary tumors are possible and provide valuable tool for the study of various stages of mammary cancer development.

Multiple endocrine neoplasia type 2 (MEN-2) is an inherited tumor syndrome that includes medullary thyroid carcinoma (MTC), primary hyperparathyroidism, pheochromocytoma and other non-endocrine diseases. Since the first RET missense mutations in association with MEN-2 were identified, RET mutation analysis had a great impact in the clinical management of MEN-2, such as in early diagnosis and treatment of MTC. Presently, early total thyroidectomy provides real cure of MTC for cases in which molecular diagnosis has been performed at early ages. After RET mutation identification, family members should be screened for this mutation by using methods as DGGE, SSCP, restriction enzyme, genetic sequencing or mini-sequencing. In this paper, we briefly review our experience with the direct RET gene sequencing and DGGE approaches. In 50 typical MEN-2 patients analyzed using both methods, we found no false results suggesting that DGGE is a reliable screening method for RET proto-oncogene mutation analysis.

No abstract

Sodium dichloroacetate (DCA) is a metabolic regulator used to treat diabetes. Since DCA inhibits pyruvate dehydrogenase kinase, decreasing lactic acid formation, it can reverse the Warburg effect in cancer cells, promoting apoptosis. Therefore, this study aimed to investigate the potential of DCA as a drug repurposing candidate for the treatment of melanoma. For the in-vitro assay, murine B16-F10 melanoma cells were treated with 0.5, 1, 5, 10, 20 or 50 mM DCA for 3 days, analyzed with the crystal violet method. The in-vivo effect of DCA was evaluated in B16-F10 tumor-bearing C57BL/6 mice treated with different doses of DCA (0, 25, 75 or 150 mg/kg) by gavage for 10 days, followed by measurement of tumor volume. Upon necropsy, representative slices of lung, liver, kidney, spleen and intestine were collected, processed and submitted for histopathological examination. The DCA concentrations of 10, 20 and 50 mM reduced B16-F10 cell viability after 48 and 72 h of treatment, whereas 20 and 50 mM were effective after 24 h of treatment. A significant reduction in tumor growth was observed in B16-F10 melanoma bearing mice at all doses, with no change in body weight or histology. DCA attenuates the growth of B16-F10 melanoma in vitro and in vivo, without systemic toxic effects. Therefore, DCA is a candidate for drug repurposing against melanomas.

À técnica do laboratório, Marguiti Isaura Soares Silva por todo respaldo técnico e principalmente pela amizade. Aos colegas do Laboratório de Oncologia Experimental que se tornaram amigos. Por toda ajuda e ensinamento, consideração, amizade, carinho, preocupação e por todos os momentos de alegria que pudemos compartilhar. Luciana, Daniel,