Cellular effects of a turmeric root and rosemary leaf extract on canine neoplastic cell lines.

BACKGROUND: The use of nutraceuticals is gaining in popularity in human and canine oncology with a relatively limited understanding of the effects in the vastly different tumor types seen in canine oncology. We have previously shown that turmeric root (TE) and rosemary leaf (RE) extracts can work synergistically to reduce neoplastic cell growth, but the mechanisms are poorly understood and require further elucidation. RESULTS: Three different canine cell lines (C2 mastocytoma, and CMT-12 mammary carcinoma, D17 osteosarcoma) were treated with 6.3 µg mL-1 extract individually, or 3.1 µg mL-1 of each extract in combination based on studies showing synergy of these two extracts. Apoptosis, antioxidant effects, cellular accumulation of curcumin, and perturbation of signaling pathways were assessed. The TE + RE combination treatment resulted in Caspase 3/7 activation and apoptosis in all cell lines, beyond the effects of TE alone with the CMT-12 cell line being most susceptible. Both extracts had antioxidant effects with RE reducing reactive oxygen species (ROS) by 40-50% and TE reducing ROS by 80-90%. In addition RE treatment enhanced the c-jun N-terminal kinase (JNK) activity in the C2 cell line and TE + RE exposure increased activated JNK by 4-5 times in the CMT-12 cell line. Upon further examination, it was found that RE treatment caused a significant increase in the cellular accumulation of curcumin by approximately 30% in the C2 and D17 cell lines, and by 4.8-fold in the CMT-12 cell line. This increase in intracellular curcumin levels may play a role in the synergy exhibited when using TE and RE in combination. CONCLUSIONS: The use of RE in combination with TE induces a synergistic response to induce apoptosis which is better than either extract alone. This appears to be related to a variable increased TE uptake in cells and activation of pathways involved in the apoptotic response.

Clinical efficacy and safety of a water-soluble micellar paclitaxel (Paccal Vet) in canine mastocytomas.

OBJECTIVE: To determine the clinical efficacy and safety of a cremophor-free formulation of paclitaxel (Paccal Vet, Oasmia Pharmaceuticals) in dogs with mast cell tumours. METHODS: Paccal Vet was administered at a median dose of 145 (range, 135 to 150) mg/m(2) intravenously once every 21 days for three cycles to 29 dogs with macroscopic grade 2 or 3 mast cell tumour. Efficacy was assessed by tumour response (Response Evaluation Criteria in Solid Tumours version 1.0) and performance status score. Progression-free survival, quality of life and safety/adverse events were also evaluated. Clinical safety was assessed by clinicopathological analyses and recording of adverse events. RESULTS: Complete or partial response was observed in 59% of dogs. Performance status score remained constant or improved for 20 dogs and decreased by one grade for 9 dogs. Median time to progression was 247 (range, 42 to 268) days. Expected, transient frequently subclinical adverse events (primarily grade 3/4 neutropenia and grade 1/2 leukopenia) were observed in the majority of dogs. Nine dogs were euthanased and one dog died due to disease progression. CLINICAL SIGNIFICANCE: Paccal Vet appears to be a clinically safe and effective treatment for canine mast cell tumours. Further controlled confirmatory investigation is warranted.

Calcitriol (1,25-dihydroxycholecalciferol) enhances mast cell tumour chemotherapy and receptor tyrosine kinase inhibitor activity in vitro and has single-agent activity against spontaneously occurring canine mast cell tumours.

Calcitriol potentiates the effect of multiple chemotherapy agents in a variety of tumour models. In this study, we examine whether calcitriol increases chemotherapy or tyrosine kinase inhibitor in vitro cytotoxicity in canine mastocytoma C2 cells. We also evaluate the in vivo effect of DN101, a highly concentrated oral formulation of calcitriol designed specifically for cancer therapy, as a single-agent therapy in dogs with mast cell tumours (MCTs). Calcitriol exhibits synergistic, antiproliferative activity when used in combination with CCNU, vinblastine, imatinib or toceranib in vitro. The concentrations required for 50% growth inhibition were generally two- to six-fold lower when the drugs were used in combination than when used individually. High-dose oral calcitriol induced remission in 4 of 10 dogs (one complete remission, three partial remissions), although the majority experienced toxicity, necessitating discontinuation of the trial. Further evaluation of calcitriol in combination therapy for dogs with MCTs is warranted.

Adjuvant electrochemotherapy for the treatment of incompletely resected canine mast cell tumors.

BACKGROUND: Electrochemotherapy (ECT) is a novel anticancer therapy that combines the delivery of trains of appropriate waveforms with the local administration of chemotherapy agents. The purpose of this investigation was to assess the adjuvant potentials of ECT for the treatment of incompletely excised mast cell tumors (MCT). MATERIALS AND METHODS: Twenty-eight privately-owned dogs with incompletely removed MCT were treated with intralesional bleomycin (1.5 IU/cm2) followed by the application of trains of biphasic pulses (8 pulses, 1300 V/cm, 50 + 50 micros duration, 1 Hz frequency). RESULTS: The overall response rate was 85% with a mean estimated time to recurrence of 52.76 +/- 6.5 months (range: 39.99 to 65.54 months, 95% CI). At the time of writing this report, the median survival time was not reached. Three dogs died of metastatic disease that they developed at the same time of local recurrence, one developed multiple cutaneous nodules at different locations and one with recurrence was re-treated and is currently disease-free after 22 months. No major local or systemic toxicities were noted for the duration of the study. CONCLUSION: ECT is a safe and effective therapy for incompletely excised MCTs in companion animals. Its ease of administration, lack of toxicities and low cost make it an attractive alternative to standard treatments and warrants further investigation.

[Pathobiochemical importance of phospholipases for the release of mast cell mediators]. / Pathobiochemische Bedeutung von Phospholipasen für die Freisetzung von Mastzellmediatoren.

We investigated the influence of polyunsaturated fatty acids on the activity of the cytosolic phospholipase A2 (cPLA2) in the canine mastocytoma cell line C2 as a model for canine atopic dermatitis (CAD). Cells were cultured in a basic medium or in media supplemented with different fatty acids (14 microM) for eight days. The supplemented fatty acids were linoleic acid (18:2n6), alpha-linolenic acid (18:3n3), gamma-linolenic acid (18:3n6) and docosahexaenoic acid (22:6n3). We measured enriched concentrations of the added fatty acid, their delta6-desaturated and elongated products. However, delta5-desaturated products were not increased. Culturing of C2 in 18:3n3 supplemented medium reduced the cPLA2 activity. Furthermore in these cells and in C2 cultured in 22:6n3 supplemented medium decreased the cPLA2 activity after stimulation. The reduced cPLA2 activity by the changed fatty acid pattern of C2 cultured in 18:3n3 or 22:6n3 possibly explain the beneficial effects of these fatty acids in CAD because increased cPLA2 activity is accompanied by enhanced release of proinflammatory type 2 prostaglandins and type 4 leukotrienes.