Anticancer effect of superoxide dismutase on canine mammary gland tumour in vitro.

BACKGROUND: Reactive oxygen species (ROS) have been shown to promote tumour growth and metastasis in human cell lines. The superoxide anion (•O2 - ) is produced during ROS formation and is involved in tumour cell signalling. OBJECTIVES: Superoxide dismutase (SOD) has been applied to canine mammary gland tumours to investigate its antitumour effects in vitro. METHODS: Cell proliferation, cell cycle cell migration assays, reverse transcription-quantitative polymerase chain reaction, and western blot analysis were performed to determine the effects of SOD on canine mammary tumour cell line. RESULTS: SOD treatment resulted in anti-proliferative effects and mediated cell cycle arrest in the canine mammary gland tumour cell lines (CIPp and CIPm). It also downregulated the expression of N-cadherin and Vimentin. CONCLUSIONS: The results confirmed that SOD inhibits tumour cell proliferation and migration, thus supporting the potential applications of SOD as a chemotherapeutic agent for canine mammary gland tumours.

Hypoxia Increases the Proliferative and Metastatic Ability of Canine Mammary Tumor Cells via Up-regulation of TSG-6.

BACKGROUND/AIM: HIF1α-induced hypoxia is a major characteristic of solid tumors that plays an important role in cancer growth, metastasis, and chronic inflammation. Tumor necrosis factor (TNF) stimulated gene (TSG)-6 is a strong regulator of anti-inflammatory pathways, but its role in cancer cells remains unclear. We hypothesized that hypoxia up-regulates TSG-6, thereby increasing the metastatic and growth potential of cancer cells. MATERIALS AND METHODS: Primary and metastatic canine mammary gland tumor (MGT) cell lines (CIPp and CIPm), were transfected with TSG-6 specific siRNA and treated with cobalt chloride (CoCl2) for 48 h to chemically induce a hypoxia environment. The expression of hypoxia-inducible factor-1-alpha (HIF1α) was evaluated by RT-qPCR and western blot analysis. The metastatic ability of cancer cells and cell cycle distribution were assessed with extracellular matrix invasion assays and flow cytometry. RESULTS: HIF1α up-regulation, induced by CoCl2, was significantly inhibited in the TSG-6-knockdown group in both canine MGT cell lines. The change in the expression levels of HIF1α corresponded to the change of invading cells in the TSG-6-knockdown group. TSG-6-knockdown in the hypoxia group showed decreased proliferation, associated with G2/M phase arrest. CONCLUSION: HIF1α expression in hypoxic condition is regulated by TSG-6 expression in canine MGT. TSG-6-knockdown causes down-regulation of HIF1α, thereby reducing the metastatic and proliferative abilities of cancer cells. TSG-6 in canine MGT has a potential as a therapeutic target in anti-cancer therapy.

Effects of Cyclooxygenase-2 in Canine Melanoma-derived Extracellular Vesicles on Tumor Microenvironment In Vitro.

BACKGROUND/AIM: Tumor cell-derived extracellular vesicles (TEVs) promote tumor growth and metastasis; thus, they have drawn the attention of researchers. TEVs regulate the tumor microenvironment by facilitating crosstalk between immune and stromal cells. Macrophages are one of the key components involved in malignant behavior in melanomas. Generally, when activated, macrophages polarize into M1 (pro-inflammatory) or M2 (anti-inflammatory, pro-tumor) phenotypes. However, the role of canine melanoma-derived EVs in macrophage polarization is elusive. In this study, we aimed to analyze the pro- and anti-inflammatory cytokines that are common markers for M1 or M2 macrophages in vitro. MATERIALS AND METHODS: The analysis was performed under coculture conditions of canine melanoma-derived (LMeC) EVs with canine macrophages (DH82). Quantitative reverse transcription polymerase chain reaction, western blotting, and immunofluorescence were used. RESULTS: Canine melanoma-derived EVs polarized M1 macrophages (inducible nitric oxide synthase, tumor necrosis factor α) into M2 macrophages [cluster of differentiation (CD)206, interleukin-10] and cyclooxygenase-2 is a major factor in macrophage polarization in canine melanoma-derived EVs. Furthermore, we also found that melanoma-derived EVs induced the expression of angiogenic cytokines (vascular endothelial growth factor, transforming growth factor ß) in endothelial cells. CONCLUSION: Melanoma-derived EVs perform an immunomodulatory function and can be used as targets in anti-inflammatory treatment.

Transient thrombocytopenia in a cat following G-CSF treatment.

A 4-year-old, castrated male, Russian blue cat with idiopathic epilepsy was diagnosed with neutropenia. The neutropenia was classified as idiopathic after blood tests and abdominal imaging did not reveal an infectious, inflammatory or neoplastic aetiology. As a treatment trial for idiopathic neutropenia, the cat was administered granulocyte colony-stimulating factor by subcutaneous injection once daily for 3 days. Two weeks after completion of granulocyte colony-stimulating factor therapy, the cat developed severe thrombocytopenia, with the granulocyte colony-stimulating factor therapy considered to be the most likely cause. No treatment was initiated, and the thrombocytopenia had resolved spontaneously by 2 weeks after diagnosis. This is the first reported case of transient severe thrombocytopenia in a cat following granulocyte colony-stimulating factor treatment.

Canine peripheral blood mononuclear cell-derived B lymphocytes pretreated with lipopolysaccharide enhance the immunomodulatory effect through macrophage polarization.

BACKGROUND: Preconditioning with lipopolysaccharide (LPS) is used to improve the secretion of anti-inflammatory agents in B cells. However, there are only a few studies on canine B cells. OBJECTIVE: This study aimed to evaluate the immune regulatory capacity of canine peripheral blood mononuclear cell-derived B cells pretreated with LPS. METHODS: Canine B cells were isolated from canine peripheral blood mononuclear cells, which were obtained from three healthy canine donors. The B cells were preconditioned with LPS, and then cell viability and the expression of the regulatory B cell marker were assessed. Finally, RNA extraction and immunofluorescence analysis were performed. RESULTS: LPS primed B cells expressed the interleukin (IL)-10 surface marker and immunoregulatory gene expression, such as IL-10, programmed death-ligand 1, and transforming growth factor beta. Macrophages in the inflammatory condition cocultured with primed B cells were found to have significantly down-regulated pro-inflammatory cytokine, such as tumor necrosis factor-α, and up-regulated anti-inflammatory cytokines such as IL-10. Additionally, it was revealed that co-culture with primed B cells re-polarized M1 macrophages to M2 macrophages. CONCLUSIONS: This study revealed that LPS-primed B cells have an anti-inflammatory effect and can re-polarize macrophages, suggesting the possibility of using LPS-primed B cells as a therapeutic agent for its anti-inflammatory effects and immune modulation.

Successful treatment of occult hyperadrenocorticism with mitotane but not trilostane in a dog.

BACKGROUND: Occult (or atypical) hyperadrenocorticism (HAC) shows clinical signs and laboratory abnormalities similar to classic hyperadrenocorticism, but normal signs in routine screening tests such as the corticotropin (ACTH) stimulation test and low-dose dexamethasone suppression test (LDDST). Here, we describe a case of occult HAC in a Yorkshire terrier treated with mitotane. CASE: An 11-year-old spayed female presented to the Veterinary Teaching Hospital of Seoul National University because of respiratory distress symptoms, polyphagia, and polydipsia, suggestive of HAC. In abdominal sonography, enlargement of the caudal pole of the left adrenal gland was found, but the cortisol level of post-ACTH stimulation test was below the cut-off value, and LDDST was negative. To finalise the diagnosis of occult HAC, 17-hydroxyprogesterone (17-OHP) was examined. The concentrations of 17-OHP (pre- and post-ACTH stimulation) were found to be elevated. As occult HAC was highly suspected, we prescribed trilostane for trial therapy. At first, the clinical signs improved, but they later worsened. We changed medication as trilostane to mitotane, and the symptoms were relieved after mitotane administration. CONCLUSION: This is a unique case of occult HAC in which the response to mitotane was better than trilostane.