Genetically modified bacteria are a potentially powerful anticancer therapy due to their tumor targeting capacity, inherent antitumor activity, and ability to serve as efficient vectors for gene ...delivery. This study sought to characterize the acute and short-term toxicities and tumor colonization rates of a genetically modified Salmonella typhimurium (VNP20009) in dogs with spontaneous tumors, in the context of a phase I dose escalation trial.
Forty-one pet dogs with a variety of malignant tumors received weekly or biweekly i.v. infusions of VNP20009, at doses ranging from 1.5 x 10(5) to 1 x 10(8) cfu/kg. Vital signs and clinicopathologic variables were monitored regularly. Incisional biopsies were obtained before and 1 week following the first infusion for histopathology and bacterial culture.
The nominal maximum tolerated dose was 3 x 10(7) cfu/kg, with refractory fever and vomiting being the dose-limiting toxicities. One treatment-related acute death occurred. Bacteria were cultured from tumor tissue in 42% of cases. Thirty-five patients were evaluable for antitumor response. Major antitumor responses were seen in 15% (4 complete response and 2 partial response), and disease stabilization for at least 6 weeks in 10%.
Administration of VNP20009 at doses with acceptable toxicity results in detectable bacterial colonization of tumor tissue and significant antitumor activity in tumor-bearing dogs.
Spontaneous tumors in companion animals (dog and cat) offer a unique opportunity as models for human cancer biology and translational cancer therapeutics. The relatively high incidence of some ...cancers, similar biologic behavior, large body size, comparable responses to cytotoxic agents, and shorter overall lifespan are the factors that contribute to the advantages of the companion animal model. The tumor types that offer the best comparative interest include lymphoma/leukemia, osteosarcoma, STS, melanoma, and mammary tumors. With the increase in new therapeutic agents (traditional chemotherapy, gene therapy, biologic agents, etc.), the companion animal model can provide useful populations to test new agents where efficacy and toxicity can be examined.
Spontaneous tumors in dogs and cats are appropriate and valid model tumor systems available for testing cancer therapeutic agents or studying cancer biology. The pet population is a vastly ...underutilized resource of animals available for study. Dogs and cats develop spontaneous tumors with histopathologic and biologic behavior similar to tumors that occur in humans. The tumors with potential relevance for human cancer biology include osteosarcoma, mammary carcinoma, oral melanoma, oral squamous cell carcinoma, nasal tumors, lung carcinoma, soft tissue sarcomas, and malignant non-Hodgkin's lymphoma. Canine osteosarcoma is a malignant aggressive bone tumor with a 90% metastasis rate after surgical amputation. Its predictable metastatic rate and pattern and its relative resistance to chemotherapy make this tumor particularly attractive for studying anti-metastasis approaches. Canine and feline malignant mammary tumors are fairly common in middle-aged animals and have a metastatic pattern similar to that in women; that is, primarily to regional lymph nodes and lungs. Chemotherapy has been minimally effective, and these tumors may be better models for testing biological response modifiers. Oral tumors, especially melanomas, are the most common canine malignant tumor in the oral cavity. Metastasis is frequent, and the response to chemotherapy and radiation has been disappointing. This tumor can be treated with anti-metastatic approaches or biological response modifiers. Squamous cell carcinomas, especially in the gum, are excellent models for radiation therapy studies. Nasal carcinomas are commonly treated with radiation therapy. They tend to metastasize slowly, but have a high local recurrence rate. This tumor is suitable for studying radiation therapy approaches. Primary lung tumors and soft tissue sarcomas are excellent models for studying combined modality therapy such as surgery with chemotherapy or biological response modifiers. Finally, non-Hodgkin's lymphoma is a common neoplastic process seen in the dog. These tumors respond to combination chemotherapy and have great potential as a model for newer chemotherapeutic agents and biological response modifiers. This paper will further elaborate on the relative merits of each tumor type as a model for human cancer therapy and biology.
Spontaneous canine oral melanoma (COM) is a highly metastatic cancer, resistant to chemotherapy, and can serve as a model for cancer immunotherapy. Liposome-encapsulated muramyl ...tripeptide-phosphatidylethanolamine (L-MTP-PE) can activate the tumoricidal activity of the monocyte-macrophage system following i.v. injection. The objective of these studies was to evaluate the therapeutic effectiveness of L-MTP-PE administered alone and combined with recombinant canine granulocyte macrophage colony-stimulating factor (rcGM-CSF) in dogs undergoing surgery for oral melanoma. Ninety-eight dogs with histologically confirmed, clinically staged, oral melanoma were entered into two randomized, double-blind, surgical adjuvant trials. In trial 1, 50 dogs were stratified based on clinical stage and randomized to once a week L-MTP-PE or lipid equivalent (control). When all of the clinical stages were combined, no difference in disease-free survival or in survival time (ST) were detected. However, within stage I, dogs receiving L-MTP-PE had a significant increase in ST compared with control, with 80% of the dogs treated with L-MTP-PE still alive at >2 years. Within each stage II and stage III, there was no difference detected between the treatment groups. In trial 2, 48 dogs were stratified on the basis of clinical stage and extent of surgery (simple resection or radical excision), treated with L-MTP-PE two times a week, and randomized to rcGM-CSF or saline (placebo) given s.c. daily for 9 weeks. Within each stage and when all of the stages were combined, there was no difference between the treatment groups. In both studies, stage I COM is associated with a better prognosis. No effect on survival was observed with regard to tumor location in the oral cavity, sex, type/extent of surgery, or age. In a subset of dogs tested, pulmonary alveolar macrophage cytotoxicity was enhanced with combined rcGM-CSF and L-MTP-PE but not in dogs treated with L-MTP-PE alone. The present study indicates that after surgery, L-MTP-PE administered alone or combined with rcGM-CSF showed no significant antitumor activity in treating advanced stage COM. In early stage COM, L-MTP-PE was shown to result in a prolongation of ST. Furthermore, this study provides additional rationale for the use of the dog model for human malignant melanoma.
Canine hemangiosarcoma (HSA) is a devastating disease. Investigation of novel therapies has been limited by the limited availability of canine HSA-derived cell lines. We report the development of a ...canine HSA-derived cell line, DEN-HSA, which recapitulates features of angiogenic endothelium. DEN-HSA cells were derived from a spontaneous HSA arising in the kidney of a dog. DEN-HSA displayed surface molecules distinctive of endothelial histogenesis, including factor VIII-related antigen, ICAM-1 and α
vβ
3 integrin. In vitro, DEN-HSA formed microvascular tube-like structures on Matrigel
®, and proliferated in response to a variety of angiogenic growth factors. The cells expressed mRNA and protein specific for bFGF and its receptors, and VEGF and its receptors, among others. DEN-HSA conditioned medium evoked a marked angiogenic response in a murine corneal pocket assay, indicating potent proangiogenic activity of substances secreted by this cell line. This research confirms the DEN-HSA cell line as endothelial in origin, suggests the presence of angiogenic growth factor autocrine loops, and offers the potential to utilize DEN-HSA cells for the study of novel therapies that modulate endothelial proliferation.
Sixteen dogs with histologically confirmed appendicular osteosarcoma were treated by amputation followed by cisplatin and doxorubicin chemotherapy. All dogs began chemotherapy within 24 hours of ...surgery. Cisplatin was administered at 50 mg/m2 intravenously (IV) concurrent with saline‐induced diuresis. Doxorubicin was administered 24 hours later at 15 mg/m2 as a slow IV bolus. This protocol was given on a 21‐day cycle for 4 cycles. No dose delays were required, but dose reduction of doxorubicin was required in 2 dogs because of neutropenia. Thoracic radiography was performed every 2 months after completion of therapy to monitor for metastatic disease. Two dogs were still alive and free from disease at the time of last contact (24 and 75 months, respectively). Postmortem examinations were performed on 13 of the 14 dogs that died. Eight of these dogs were euthanized because of metastatic osteosarcoma. Of the remaining 5 dogs, euthanasia was performed because of complications of idiopathic megaesophagus (n = 1), arthritis (n = 2), and hemangiosarcoma (n = 2). The median disease‐free interval and survival times were 15.7 and 18 months, respectively. When compared to a historical group of 36 dogs with appendicular osteosarcoma treated with surgery and 4 doses of cisplatin, both disease‐free interval and overall survival were significantly longer in the study population (P < .015 and P < .007, respectively).
Prognostic factors for treatment of malignant lymphoma in dogs Teske, E. (Utrecht University, Utrecht, The Netherlands); Heerde, P. van; Rutteman, G.R ...
Journal of the American Veterinary Medical Association,
12/1994, Letnik:
205, Številka:
12
Journal Article
Recenzirano
Odprti dostop
Pretreatment characteristics of 138 dogs with malignant lymphoma were analyzed to determine prognostic factors associated with outcome (ie, complete response rate, time to relapse after complete ...response, survival time). Dogs were all treated for 10 weeks, using a standard induction chemotherapy protocol, and were then given asparaginase weekly. Once the disease became progressive, second-line chemotherapy was instituted. Age, sex, weight, clinical stage, performance grade, immunophenotype, and malignancy grade assigned according to the National Cancer Institute's Working Formulation were not associated with complete response rate. However, malignancy grade assigned according to the Kiel classification was found to be associated with complete response rate; dogs with high-grade malignancies had a significantly higher complete response rate than did dogs with low-grade malignancies. By means of multivariate analysis, clinical stage and immunophenotype were found to be prognostic factors for time to relapse (among dogs that had had a complete response) and survival time. In addition, malignancy grade assigned according to the Kiel classification was found to be a prognostic factor for time to relapse; whereas, malignancy grade assigned according to the Working Formulation was determined to be a prognostic factor for survival time.
To further characterize the role of hepatocyte growth factor-scatter factor (HGF-SF) and its receptor (c-Met) in osteosarcoma (OS), human OS cell lines with low (SAOS-2) and high (SAOS-LM2) ...metastatic potential, and cell lines derived from spontaneous canine OS were studied. All cell lines were evaluated for c-Met and HGF-SF expression and receptor activation using Northern, RT-PCR, and Western blot analyses, respectively. Functional activity of receptor-ligand interaction was measured using c-Met phosphorylation status, proliferation assays (anchorage-dependent and -independent), Matrigel invasion, modulation of urokinase plasminogen activator (uPA) expression, and cell dispersion (scattering). All cell lines exhibited steady-state mRNA expression of c-Met. The canine OS cell lines also expressed HGF-SF mRNA as determined by RT-PCR analysis. Western analysis showed c-Met protein expression and HGF-stimulated (human) or constitutive (canine) receptor autophosphorylation. Treatment with recombinant human HGF resulted in enhanced proliferation in 3 of 5 OS cell lines and enhanced colony formation in 2 of 5 OS cell lines. Matrigel invasion was significantly enhanced in 3 of the cell lines and uPA levels were significantly increased in the SAOS-2 cells following HGF treatment. Scattering was enhanced in both the SAOS-2 and SAOS-LM2 cells. These data support the involvement of c-Met and HGF-SF in the growth and progression of human and canine OS, and may offer new targets for the development of therapeutic strategies for OS.
