An evaluation of the combination effect of zoledronate and chemotherapeutic agents in canine osteosarcoma cells.

Introduction: Osteosarcoma (OSA) is an aggressive form of bone cancer in both dogs and humans. The treatment options for metastatic (stage III) OSA are currently limited and the prognosis is poor. Zoledronate, a second generation amino-bisphosphonate, is commonly used for palliation of cancer induced bone pain. Zoledronate has also demonstrated anti-cancer properties and possibly enhances the cytotoxicity of doxorubicin in a canine histiocytosis cell line and human prostatic cancer cell line. The goal of this study was to evaluate the combination effect of zoledronate and various chemotherapeutic drugs in canine OSA cells. Methods: Canine OSA cell line (D17), cells from two canine primary OSAs, and MDCK, a canine kidney cell line, were used to evaluate the therapeutic potential of these drugs. Carboplatin, doxorubicin, vinorelbine, toceranib, and isophosphoramide mustard (active metabolite of ifosfamide) were used as chemotherapeutic agents. First, cells were treated with either zoledronate or chemotherapy drug alone for 72 hours. Cell viability was assessed using CellTiter Glo and IC5, IC10, IC20, and IC50 were calculated. Second, cells were treated with a combination of zoledronate and each chemotherapeutic agent at their IC5, IC10, IC20, and IC50 concentrations. After 72 hours, cell viability was assessed by CellTiter Glo. Results and discussion: Zoledronate, carboplatin, doxorubicin, vinorelbine, and isophosphoramide mustard showed concentration dependent decrease in cell viability. Toceranib showed decreased cell viability only at higher concentrations. When zoledronate was used in combination with chemotherapy drugs, while it showed potential synergistic effects with toceranib, potential antagonistic effects with vinorelbine and isophosphoramide mustard were observed. However, the results differed by cell line and thus, further evaluation is warranted to understand the exact mechanism of action.

Novel genomic prognostic biomarkers for dogs with cancer.

BACKGROUND: Growing evidence from dogs and humans supports the abundance of mutation-based biomarkers in tumors of dogs. Increasing the use of clinical genomic diagnostic testing now provides another powerful data source for biomarker discovery. HYPOTHESIS: Analyzed clinical outcomes in dogs with cancer profiled using SearchLight DNA, a cancer gene panel for dogs, to identify mutations with prognostic value. ANIMALS: A total of 127 cases of cancer in dogs were analyzed using SearchLight DNA and for which clinical outcome information was available. METHODS: Clinical data points were collected by medical record review. Variables including mutated genes, mutations, signalment, and treatment were fitted using Cox proportional hazard models to identify factors associated with progression-free survival (PFS). The log-rank test was used to compare PFS between patients receiving and not receiving targeted treatment before first progression. RESULTS: Combined genomic and outcomes analysis identified 336 unique mutations in 89 genes across 26 cancer types. Mutations in 6 genes (CCND1, CCND3, SMARCB1, FANCG, CDKN2A/B, and MSH6) were significantly associated with shorter PFS. Dogs that received targeted treatment before first progression (n = 45) experienced significantly longer PFS compared with those that did not (n = 82, P = .01). This significance held true for 29 dogs that received genomically informed targeted treatment compared with those that did not (P = .05). CONCLUSION AND CLINICAL IMPORTANCE: We identified novel mutations with prognostic value and demonstrate the benefit of targeted treatment across multiple cancer types. These results provide clinical evidence of the potential for genomics and precision medicine in dogs with cancer.

Evaluation of zoledronate for the treatment of canine stage III osteosarcoma: A phase II study.

BACKGROUND: Greater than 90% of dogs with appendicular osteosarcoma will develop pulmonary metastasis despite the standard of care. Available treatments have limited efficacy for stage III disease. Zoledronate, a bisphosphonate, induces apoptosis of canine osteosarcoma cells and appears to modulate the tumour microenvironment. OBJECTIVES: This prospective, single institutional phase IIa trial investigated the use of single agent zoledronate in dogs with pulmonary metastases from osteosarcoma. METHODS: Zoledronate was administered once monthly, and thoracic radiographs were used to assess response. RESULTS: Eleven dogs were enrolled. Stable disease was achieved in two of eight dogs available for response assessment. The median progression-free survival was 28 days (range: 4-93 days). The median stage III-specific survival time was 92 days. Adverse events were reported in four dogs; two dogs developed grade III or higher toxicities. Notable adverse events included conjunctivitis, fever, hypocalcaemia, and hypophosphatemia. CONCLUSIONS: Zoledronate appears to have limited efficacy as a single agent for stage III osteosarcoma and may be associated with unexpected toxicity in this population. This clinical trial was registered on the AVMA Animal Health Studies Database (AAHSD004396).

Transcriptomic Analysis of Canine Osteosarcoma from a Precision Medicine Perspective Reveals Limitations of Differential Gene Expression Studies.

Despite significant advances in cancer diagnosis and treatment, osteosarcoma (OSA), an aggressive primary bone tumor, has eluded attempts at improving patient survival for many decades. The difficulty in managing OSA lies in its extreme genetic complexity, drug resistance, and heterogeneity, making it improbable that a single-target treatment would be beneficial for the majority of affected individuals. Precision medicine seeks to fill this gap by addressing the intra- and inter-tumoral heterogeneity to improve patient outcome and survival. The characterization of differentially expressed genes (DEGs) unique to the tumor provides insight into the phenotype and can be useful for informing appropriate therapies as well as the development of novel treatments. Traditional DEG analysis combines patient data to derive statistically inferred genes that are dysregulated in the group; however, the results from this approach are not necessarily consistent across individual patients, thus contradicting the basis of precision medicine. Spontaneously occurring OSA in the dog shares remarkably similar clinical, histological, and molecular characteristics to the human disease and therefore serves as an excellent model. In this study, we use transcriptomic sequencing of RNA isolated from primary OSA tumor and patient-matched normal bone from seven dogs prior to chemotherapy to identify DEGs in the group. We then evaluate the universality of these changes in transcript levels across patients to identify DEGs at the individual level. These results can be useful for reframing our perspective of transcriptomic analysis from a precision medicine perspective by identifying variations in DEGs among individuals.

Evaluation of local toxic effects and outcomes for dogs undergoing marginal tumor excision with intralesional cisplatin-impregnated bead placement for treatment of soft tissue sarcomas: 62 cases (2009-2012).

OBJECTIVE To evaluate outcomes for dogs following marginal tumor excision and intralesional placement of cisplatin-impregnated beads for the treatment of cutaneous or subcutaneous soft tissue sarcomas (STSs) and assess local toxic effects of cisplatin-impregnated beads in these patients. DESIGN Retrospective case series. ANIMALS 62 client-owned dogs. PROCEDURES Medical records were reviewed to identify dogs with STSs treated with marginal excision and intralesional placement of cisplatin-impregnated beads. Patient signalment; tumor location, type, and grade; dates of tumor resection and bead placement; number of beads placed; and concurrent treatments were recorded. Data regarding toxicosis at the bead site (up to the time of suture removal) and tumor recurrence were collected; variables of interest were evaluated for associations with these outcomes, and systemic adverse effects (if any) were recorded. RESULTS 24 of 51 (47%) evaluated dogs had toxicosis at bead placement sites (classified as mild [n = 12] or moderate [10] in most). Fifteen of 51 (29%) tumors recurred. Median disease-free interval was not reached for dogs with grade 1 and 2 STSs, whereas that for dogs with grade 3 STSs was 148 days. Disease-free survival rates of dogs with grade 1 and 2 tumors at 1, 2, and 3 years were 88%, 75%, and 64%, respectively. One dog was treated for presumptive systemic toxicosis but recovered with medical treatment. CONCLUSIONS AND CLINICAL RELEVANCE Cisplatin-impregnated beads were generally well tolerated; good results were achieved for dogs with grade 1 or 2 STSs. Prospective, controlled studies are needed to determine efficacy of this treatment for preventing recurrence of marginally excised STSs in dogs.