Evaluation of ifosfamide salvage therapy for metastatic canine osteosarcoma

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.

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).

Sorafenib and Doxorubicin Show Synergistic Effects in Human and Canine Osteosarcoma Cell Lines

Osteosarcoma (OSA) is the most common bone tumor in both humans and dogs and has a nearly ten-fold higher incidence in dogs than humans. Despite advances in the treatment of other cancers, the overall survival rates for OSA have stagnated for the past four decades. Therefore, there is a great need to identify novel and effective treatments. We screened a series of tyrosine kinase inhibitors and selected sorafenib, a multi-kinase inhibitor, for further evaluation alone and in combination with cisplatin, carboplatin, and doxorubicin on canine and human OSA cell lines. Our data point to synergistic effects when sorafenib is combined with doxorubicin, but not when combined with cisplatin or carboplatin, in both human and canine OSA. Based on current findings, clinical trials using a combination of doxorubicin and sorafenib in proof-of-concept studies in dogs are warranted. These studies can be carried out relatively quickly in dogs where case load is high and, in turn, provide useful data for the initiation of clinical trials in humans.

Feasibility and safety of whole lung irradiation in the treatment of canine appendicular osteosarcoma

Whole lung irradiation (WLI) has been used successfully in humans as an adjuvant treatment for osteosarcoma. The aim of this study is to describe the feasibility and safety of WLI in dogs with appendicular osteosarcoma. Twelve client-owned dogs with appendicular osteosarcoma that had successfully completed amputation and four doses of carboplatin without evidence of gross metastasis were enrolled in this prospective clinical trial. Ten once-daily fractions of 1.75 Gy were administered to the planning target volume encompassing the lungs. Overall, WLI was well tolerated in these patients. No dogs developed symptoms of pneumonitis or pulmonary fibrosis. Haematopoietic toxicity evaluated during radiation therapy was found to be mild. The median disease free interval for WLI treated dogs was not significantly different than the median DFI for a group of historic control dogs (376 days for WLI treated dogs versus 304.5 days for control dogs; p = 0.5461). Although no significant improvement in outcome was observed with this study, WLI appears to be safe in dogs and warrants further investigation to characterize the efficacy and toxicity.

Canine thyroid carcinoma prognosis following the utilisation of computed tomography assisted staging

BACKGROUND

Metastatic disease is frequently present at the time of diagnosis of canine thyroid carcinoma; however, utilisation of computed tomography (CT) alone for staging pre-treatment has been rarely reported in the veterinary literature.

METHODS

The aims of this retrospective study were to stage affected dogs using CT findings of the cervical and thoracic regions, combined with histopathology/cytology results, in order to assess whether metastatic disease/WHO staging was of prognostic significance.

RESULTS

Fifty-eight dogs were included in the study. Classification of cases into WHO stages I, II, III and IV were 10%, 50%, 9% and 31%, respectively. No statistically significant effect of WHO stage classification on overall survival/follow-up time was found (P = .576). Surgery resulted in a statistically significant increase in overall survival/follow-up time (P < .01). There was no statistically significant effect on overall survival/follow-up time in dogs that received medical therapy, either as sole therapy or as an adjunctive post-surgery (P = .198).

CONCLUSION

In summary, this study documents the metastatic rate of canine thyroid carcinoma using CT for staging pre-treatment. Staging utilising CT revealed a higher distant metastatic rate in dogs with thyroid carcinoma when compared to historical studies using different imaging techniques. As long-term outcomes are possible for cases with advanced disease, surgical intervention could still be considered.

Targeting Mechanotransduction in Osteosarcoma: A Comparative Oncology Perspective

Mechanotransduction is the process in which cells can convert extracellular mechanical stimuli into biochemical changes within a cell. While this a normal process for physiological development and function in many organ systems, tumour cells can exploit this process to promote tumour progression. Here we summarise the current state of knowledge of mechanotransduction in osteosarcoma (OSA), the most common primary bone tumour, referencing both human and canine models and other similar mesenchymal malignancies (e.g., Ewing sarcoma). Specifically, we discuss the mechanical properties of OSA cells, the pathways that these cells utilise to respond to external mechanical cues, and mechanotransduction-targeting strategies tested in OSA so far. We point out gaps in the literature and propose avenues to address them. Understanding how the physical microenvironment influences cell signalling and behaviour will lead to the improved design of strategies to target the mechanical vulnerabilities of OSA cells.

Autologous cancer cell vaccination, adoptive T-cell transfer, and interleukin-2 administration results in long-term survival for companion dogs with osteosarcoma

Background

Osteosarcoma (OSA) in dogs is an aggressive bone tumor with frequent chemotherapy failure and translational relevance for human health.

Hypothesis/Objectives

We hypothesized that dogs with OSA could be treated safely by ex vivo activated T‐cells that were generated by autologous cancer vaccination and supported by interleukin‐2 (IL‐2) treatment with survival more than twice that reported for amputation alone.

Animals

Osteosarcoma‐bearing dogs (n = 14) were enrolled in a single‐arm prospective trial after complete staging before amputation. Four healthy dogs also were treated in a safety study.

Methods

Autologous cancer cell vaccinations were administered intradermally and dogs underwent leukapheresis. Mononuclear cell products were stimulated ex vivo with a T‐cell‐activating agent. Activated product was transfused and 5 SC IL‐2 injections were administered q48h. Dogs were monitored for metastasis by thoracic radiography every 3 months.

Results

Autologous cancer cell vaccine and activated cellular therapy (ACT) products were successfully generated. Toxicity was minimal after premedicants were instituted before ACT. With premedication, all toxicities were grade I/II. Median disease‐free interval for all dogs was 213 days. One dog developed cutaneous metastasis but then experienced spontaneous complete remission. Median survival time for all dogs was 415 days. Five dogs survived >730 days.

Conclusions and Clinical Importance

This immunotherapy protocol without cytotoxic chemotherapy is safe and tolerable. Compared to historical amputation reports, survival was notably prolonged in this group of patients. Additional prospective studies are warranted to elucidate active immunologic mechanisms and further improve disease response and survival.

Metastatic immune infiltrates correlate with those of the primary tumour in canine osteosarcoma

Our lack of understanding of the immune microenvironment in canine osteosarcoma (cOSA) has limited the identification of potential immunotherapeutic targets. In particular, our ability to utilize readily available tissue from a dog's primary tumour to predict the type and extent of immune response in their pulmonary metastatic lesions is unknown. We, therefore, collected 21 matched pairs of primary tumours and pulmonary metastatic lesions from dogs with OSA and performed immunohistochemistry to quantify T-lymphocyte (CD3), FOXP3+ cell, B-lymphocyte (Pax-5), and CD204+ macrophage infiltration. We found that T-lymphocytes and FOXP3+ infiltrates in primary tumours positively correlated with that of metastatic lesions (ρ = 0.512, P = 0.038 and ρ = 0.698, P = 0.007, respectively), while a strong trend existed for CD204+ infiltrates (ρ = 0.404, P = 0.087). We also observed T- and B-lymphocytes, and CD204+ macrophages to be significantly higher in a dog's pulmonary metastasis compared to their primary tumour (P = 0.018, P = 0.018, P = 0.016, respectively), while FOXP3+ cells were only significantly higher in metastases when all primary tumour and metastasis lesions were compared without pairing (P = 0.036). Together, these findings suggest that the metastatic immune microenvironment may be influenced by that of the primary cOSA, and that primary tumour immune biomarkers could potentially be applied to predict immunotherapeutic responses in gross metastatic disease. We, therefore, provide a rationale for the treatment of cOSA pulmonary metastases with immunotherapeutics that enhance the anti-tumour activity of these immune cells, particularly in dogs with moderate to high immune cell infiltration in their primary tumours.

Cutaneous and subcutaneous metastasis of appendicular osteosarcoma in dogs: 20 cases

Background

Metastasis of appendicular osteosarcoma is most common to the lungs and is generally considered a terminal event in dogs. Behavior and prognosis associated with cutaneous or subcutaneous metastases (CSM) is poorly defined.

Objective

Describe the population and gather prognostic information regarding appendicular osteosarcoma with CSM in dogs.

Animals

Twenty dogs with appendicular osteosarcoma and CSM.

Methods

Retrospective case series. Medical records were searched to identify dogs diagnosed with appendicular osteosarcoma that developed CSM. Demographic data, order of metastatic events, and CSM clinical features were evaluated. Kaplan‐Meier survival curves were constructed and log‐rank tests were used to compare survival between groups of dogs.

Results

In 19 dogs (95%), CSM was an incidental finding. Seventeen dogs (85%) developed pulmonary metastasis, and 1 dog (5%) developed bone metastasis. No other metastatic sites were detected before euthanasia. The median CSM‐free interval and CSM survival time were 160 days (range: 0‐542 days) and 55 days (range: 5‐336 days), respectively. The median CSM survival time was significantly longer for dogs treated with surgery and chemotherapy (94 days) or chemotherapy only (64 days) than for dogs that did not receive these treatments (11 days) (P = .002 and P = .03, respectively). No other factors were associated with survival after diagnosis of CSM.

Conclusion and Clinical Importance

The skin or subcutaneous tissue can be the first osteosarcoma metastatic site detected. After CSM diagnosis, the prognosis is grave with median survival <2 months. Although this finding could have been biased by case selection, treatment with surgery and chemotherapy may improve outcome.

β Lapachone blocks the cell cycle and induces apoptosis in canine osteosarcoma cells

ABSTRACT: Osteosarcoma is a malignant tumor of primitive bone cells with a high incidence in dogs and humans. The need for more effective drugs with less adverse consequences has pushed the development of chemotherapeutic agents from plants and other natural sources. The aim of this study was to verify the cytotoxic effects of β-lapachone, a compound present in the sawdust of Tabebuia sp. (popularly known as ipê) wood, on canine osteosarcoma cells subcultured and treated in different concentrations (0.1μm, 0.3μm e 1.0μm) and exposure times (24h, 48h e 72h). Results were obtained through Trypan blue dye exclusion, tetrazolium reducing method, cell survival assay, Annexin V-FITC and Propidium Iodine labeling, JC-1 dye labeling and cell cycle kinetics e analysis. The group treated with 0.3μm β-lapachone presented higher decrease in cell viability (80.27%, 24h, 47.41%, 48h and 35.19%, 72h) and greater progression of cytotoxicity (19.73%, 24h, 52.59%, 48h and 64.81%, 72h). The lower IC50 (0.180μm) was verified in the group treated for 72 hours. Cell growth after treatment decreased as concentration and time of exposure increased, with 0.50% survival fraction at the concentration of 1.0μm. Initial apoptosis was the most frequent type of cell death in all groups, reaching bottom in the 24-hour group treated with 0.1μm (4.26%) and peaking in the 72-hour group treated with 1.0μm (85.89%). Mitochondrial depolarization demonstrated a dose-dependent phenomenon, indicating the intrinsic apoptosis. Cell growth inhibition by blocking cell cycle in the G0/G1 phase related to the exposure the time. β-lapachone is cytotoxic for canine osteosarcoma cells, induces apoptosis and promotes cell cycle arrest in G0/G1 phase.

In vitro and in vivo activity of liposome-encapsulated curcumin for naturally occurring canine cancers

Curcumin has well-established anti-cancer properties in vitro, however, its therapeutic potential has been hindered by its poor bioavailability. Lipocurc is a proprietary liposome-encapsulated curcumin formulation that enables intravenous delivery and has been shown to reach its highest concentration within lung tissue. The goal of this study was to characterize the anti-cancer and anti-angiogenic activity of Lipocurc in vitro, in addition to evaluating Lipocurc infusions in dogs with naturally occurring cancer. We therefore evaluated the effect of Lipocurc, relative to free curcumin, on the viability of canine osteosarcoma, melanoma and mammary carcinoma cell lines, as well as the ability of Lipocurc to inhibit endothelial cell viability, migration and tube formation. We also undertook a pilot clinical trial consisting of four weekly 8-hour Lipocurc infusions in 10 cancer-bearing dogs. Tumour cell proliferation was inhibited by curcumin at concentrations exceeding those achievable in the lung tissue of dogs. Similarly, equivalent high concentrations of Lipocurc and curcumin also inhibited endothelial cell viability, migration and tube formation. Four out of six dogs completing planned infusions of Lipocurc experienced stable disease; however, no radiographic responses were detected.

What do we know about canine osteosarcoma treatment? Review

Osteosarcoma (OSA) is the most common type of bone tumors in dogs, which has high metastasis ability. 80 % of dogs with OSA die due to lung metastasis. As a result its treatment is a challenge for veterinary practitioners. The authors discuss the etiology, pathogenesis and the possible risk factors of OSA. The article focuses on literature review and the study of recent advances in OSA treatment. The authors describe therapies which have significantly prolonged the lives of dogs, as well as those that have proven to be ineffective. Advantages and disadvantages of limb amputation and limb-sparing surgery have been described. Authors present also the results of both single agent’s therapies with the most commonly used drugs as cisplatin, carboplatin and doxorubicin and compare them to the results obtained using combined chemotherapy. The use of nanotechnology as a new approach in OSA treatment in order to avoid multidrug resistance and reduce negative side effects of cytostatic drugs is presented. The main reasons of the therapies failure are also provided in this article.