Studies We Support
Bone cancer affects many of the large breeds including the Doberman Pinscher, Golden Retriever, Great Dane, Greyhound, Labrador, Leonburger, and Rottweiler. In humans advanced stage breast cancer and prostate cancer metastasize to bone cancer. Finding a cure is a win-win for both humans and our canine companions.
Several of the studies we have supported include the following:
Adoptive Cell Therapy using Genetically Engineered Natural Killer Cells for Osteosarcoma
(Bruce Walcheck, PhD, University of Minnesota, Animal Cancer Care and Research Program (ACCRP) )
Desired Outcome: ACCRP developed a series of reagents that should help identify canine natural killer cells, and possibly allow us to integrate them into treatment strategies for a variety of canine cancers.
Project overview: Natural killer cells are a type of white blood cell that is involved in eliminating cells that are infected by viruses and emerging tumor cells. Tumors eventually find a way to evade this component of the immune system, but we are developing methods to use them as part of safer and more effective cancer therapies. The technologies are well advanced for human patients, where a multitude of reagents are available. However, development of treatments using these cells in dogs has been hindered by the lack of reagents that can help us identify and characterize canine natural killer cells and engage them into treatment strategies.
Support from GREYlong enabled ACCRP scientists to develop a new battery of reagents that we believe will make identification of canine natural cells possible, and that may also allow us to integrate them into treatments that take advantage of the anti-tumor properties of these cells. Our ongoing work aims to finalize the characterization of these reagents so we can integrate them into our research pipelines and make them available to the global community of investigators studying canine cancer and immunology.
Osteosarcoma Vaccine Study (Dr. Nicola Mason, University of Pennsylvania). The goal is to stimulate the dog's immune system to target Osteosarcoma cells that have survived chemo therapy by injecting a vaccine composed of a genetically modified Listeria bacterium. Listeria expresses a tumor marker known as Her2/neu. They are testing to determine if the bacteria will stimulate the patient's immune system to kill the bacteria and also kill cells that express Her2/neu, which is shown on 40% of OS tumors in canines and humans.
The vaccinated group (post amputation and with chemo therapy) had a survival rate of 956 days versus the control group’s survival rate of 423 days. So while this is not a cure for canine osteosarcoma, it certainly is a step forward in giving our companions quality of life for an extended period of time. Currently, the vaccine is being tested at over 20 different sites within the United States.
Niche Conditioning for Metastasis in Canine Osteosarcoma (Dr. Hiro Tomiyasu, University of Minnesota). The goal of this project is to determine how bone tumors communicate with tissues at distant sites in order create favorable conditions for tumor cells to colonize and survive, thereby giving rise to metastasis.
Outcome: We built a test that can tell us if there are osteosarcoma cells “present” in a dog by looking for a series of specific markers in the blood.
Project overview: Exosomes are small membrane-bound “bags” or vesicles that are secreted by all cells. They contain molecules that the cells need to discard, as well as molecules that cells use to communicate with each other at a distance. We developed a method to identify molecules in exosomes secreted by tumor cells and to distinguish them from molecules in exosomes secreted by normal cells. To confirm that the markers we assigned to osteosarcoma cells could be used in clinical applications, we examined whether their presence in dogs with bone cancer after they received initial treatment could be used to predict the length of time that dogs would remain alive without evidence of disease relapse. Our results show that a positive result of our test (“osteosarcoma detectable”) was associated with a much worse outcome than a negative result from our test (“osteosarcoma not detectable”). In fact, about 8 in 10 dogs that had a negative result lived longer than 2 years after treatment, whereas none of the dogs that had a positive result lived longer than 1 year after treatment.
We are working to commercialize this test to help guide treatment of dogs with osteosarcoma and advancing a project to develop a comparable test for children with osteosarcoma. The upcoming project on early detection and prevention will test whether the “osteosarcoma detectable” signature can help us assign otherwise health dogs to risk groups that would enable prevention before tumors become established.
Genomics: Germline and Somatic Genetic Determinants of Osteosarcoma Outcome (David Largaespade with Logan Spector, Subbaya Subramanian, and Dr. Jaime Modiano, University of Minnesota). This study compares genetic and epigenetic alterations in the germline and in somatic cells of humans, dogs and mice with osteosarcoma to identify events that are responsible for the spectrum of clinical behaviors observed in OS. Their goal is to discover genetic markers that predict risk for OS to make early screening and targeted therapies feasible. They believe the interspecies approach affords a broader view to understanding OS.
Immunotherapy for Osteosarcoma (OSAL) (Dr. Vicki Wilke and Emily Lipsitz, University of Minnesota).
Salmonella organisms are a type of bacteria that live in the gut and are part of the normal flora of humans and many other animals. In small numbers, these organisms co-exist with other bacteria and their host, but if they expand their populations due to changes in the gut or the immune system, they can cause severe disease.
SalpIL2 is a Salmonella organism that was genetically modified to control its proliferation and its disease-causing potential. The genes that encode disease-causing toxins were deleted from its genome and a key gene that is essential for its survival and proliferation was incorporated into another gene encoding human interleukin-2 (IL-2), a master regulator of the immune system. This meant that, when administered as a therapy, any surviving organism would have to make IL-2, increasing the activity of immune cells in its “neighborhood.” While this would keep the Salmonella under control, it would also provide immunity against other conditions, like tumors.
One advantage of Salp-IL2 is that, unlike other therapeutic forms of Salmonella which must be given intravenously, it can be given orally. Upon reaching the intestine, SalpIL2 can enter the lymphatic circulation and disseminate throughout the body. However, it can only colonize and thrive in tissues where there is very low oxygen, and particularly in tumors.
The hypothesis for this project was that Salp-IL2 could be given safely to dogs with bone cancer, and that it would induce activation of the immune system and improve survival.
Nineteen dogs with bone cancer were enrolled in the OSAL clinical trial. The results showed that Salp-IL2 could be given safely to dogs before, during, and after the standard of care (amputation + chemotherapy). The time between treatment and relapse (appearance of metastasis) was slightly longer in dogs receiving Salp-IL2, although the overall survival benefit was minimal. Further study is warranted to determine if a different dose or regimen of administration, or combination with other therapies will enhance the benefit of this therapy to prolong survival or promote cancer cures.
The study supported further development of this product for human applications and a commercial effort to develop the product for the veterinary market, in particular for canine osteosarcoma. These efforts are being led by a commercial company called Salspera, LLC, a subsidiary of MD Biosciences.
Osteosarcoma (OSA) Genetic Study (Dr. Guillermo Couto, Ohio State University). OSA is the death in retired racing Greyhounds, yet it is very uncommon in AKC Greyhounds. This provides a unique opportunity to evaluate genes involved in the development and progression of OSA in the breed. In collaboration with Dr. Alvarez's lab in Nationwide Children's Hospital they are currently evaluating samples from retired racers and AKC dogs with and without OSA, in order to identify genes involved in the development of this deadly disease. In addition, because racing Greyhounds are tattooed and their pedigrees easily obtained on line, they are evaluating pedigrees in dogs with and without OSA for statistical comparison. In addition, in collaboration with Dr. Breen's (NCSU) and Lindbladh-Toh's (The Broad Institute) labs they are evaluating OSA genes in Greyhounds and other breeds, and evaluating their role in response to treatment and prognosis. Finally, they are evaluating novel treatment protocols for both Greyhounds and dogs of other breeds with OSA.
Evaluation of Cyclopamine as a Therapy for Bone Cancer (Dr. Heather Wilson, Texas A&M). Cancer arises from a single mutated cell possessing the power to replicate and form a tumor. There are many theories as to the cause and progression of this process. One theory states that a cell with stem cell capabilities divides to produce new tumor-initiating cells and daughter cells. Identifying pathways that can increase sensitivity to therapeutic intervention is paramount to finding a cure for bone cancer. Cyclopamine, a chemical found in the corn lily plant, inhibits the pathway responsible for normal embryo development and directing the regeneration of tissues. This study will research Cyclopamine's effectiveness at inhibiting tumor-initiating cells in canine osteosarcoma cell lines. The goal is to provide a new targeted therapy for pets with osteosarcoma. The final report issued stated that the research team discovered that at high does cyclopamine inhibits an important signaling stem-cell pathway used by tumor-initiating cells. Based on these findings, researchers believe that adding cyclopamine during and after traditional chemotherapy may help inhibit the growth and spread of bone cancer in dogs. They plan to pursue further research in this regard.
Examining Drug Targets for Treating Bone Cancer (Dr. Joseph J. Wakshlag, Cornell University). Preliminary evidence in humans suggests that blocking a traditional pathway of inflammation, known as the lipoxygenase (LOX) pathway, can inhibit the growth of certain cancer cells. This study examines the role the LOX pathway plays in canine osteosarcoma development and whether inhibiting it can kill bone cancer cells. The findings may lead to a new drug therapy for osteosarcoma.
MicroRNA Expression Profiling of Canine Osteosarcoma (Dr. W.C. Kisseberth, Ohio State University). Using the assumption that cancer is fundamentally a genetic disease, by studying the MicroRNA expressions, investigators hope to identify new molecular targets for therapy, which will lead to better treatment of this disease.
Canine hemangiosarcoma is an incurable tumor of cells that line blood vessels. This type of sarcoma is difficult to treat because of its aggressive behavior and rapid progression after diagnosis.
Although dogs of any age and breed are susceptible to hemangiosarcoma, it occurs more commonly in dogs beyond middle age, and in breeds such as Golden Retrievers, German Shepherd Dogs, Portuguese Water Dogs, and Skye Terriers, among others. Hemangiosarcoma develops slowly and is essentially painless; so clinical signs are usually not evident until the advanced stages when the tumors are resistant to most treatments. Fewer than fifty percent of dogs treated with surgery and intensive chemotherapy survive more than six months.
Targeted Therapy for Canine Hemangiosarcoma ( SRCBST) Dr. Modiano, Ms. Borgatti, and Dr. Vallera, University of Minnesota have developed a treatment approach for sarcomas using a genetically-engineered bacterial toxin linked to two specific proteins that target it to the tumor environment. This treatment has advanced to two clinical trials (SRCBST-1 and SRCBST-2).
Outcome: The study provided evidence for safety and efficacy of eBAT as a new therapy for canine hemangiosarcoma. eBAT has been licensed by a company called Anivive Lifesciences, which is taking the drug through the path for regulatory approval for use in animals.
Project overview: eBAT (EGF-bispecific angiotoxin) is a drug that was conceived, manufactured, developed, and tested exclusively at the University of Minnesota. eBAT acts by attaching itself to certain cells through very specific proteins on their surface and introducing into these cells a lethal bacterial toxin. The combination of “lures” in the drug make it so that only certain cells will capture it and ingest it, providing eBAT with unique properties of specificity and safety. In terms of efficacy, eBAT seems to eliminate tumors using three distinct mechanisms. The first is by directly killing cells that are responsible for forming and maintaining the tumor. This may be most effective in tumors that are in the earliest stages of formation or after treatment has eliminated all the visible tumor and all that remains are renegade cells that escaped surgery and/or chemotherapy. The second is by killing the blood vessels that provide oxygen and food to the tumor. This seems to be highly specific, as vessels that feed normal tissues are not affected. And the third is by killing cells that inhibit the immune system’s capacity to respond to the tumor. So, eBAT is, in a sense, a type of cancer immunotherapy.
The hypothesis for this project was that when added to conventional surgery and chemotherapy, eBAT would be safe and effective as a treatment for dogs with hemangiosarcoma.
Almost 50 dogs with hemangiosarcoma were treated in the SRCBST-1 and SRCBST-2 clinical trials. The results showed that eBAT was remarkably safe, and when given after surgery and before the start of chemotherapy, it almost doubled the expected survival, and it increased the proportion of dogs that lived one-and-a-half years or longer from about 1 in 10 to more than 1 in 3. This is perhaps the only treatment that has shown this degree of benefit for canine hemangiosarcoma in more than 40 years.
Based on the data from the SRCBST clinical trials, Anivive Lifesciences has licensed the drug and is working to obtain FDA approval to market it as part of the treatment for canine hemangiosarcoma. Additional work is ongoing to test the potential to use eBAT for other tumors, in the setting of cancer prevention, and as a treatment for human cancer patients.
Lymphoma is one of the most common and fatal cancers in dogs. Most dogs treated with chemo go into remission, but the cancer develops drug resistance and recurs.
Several of the studies we have supported include:
CD47 blockade as treatment for lymphoma (Dr. Modiano, Katie Anderson, and Dr. Matthew Mescher)
Outcome: The study documented that CD47 blockade, in combination with an antibody directed against malignant lymphoma cells, has extremely high potential to improve outcomes for dogs with lymphoma.
Project overview: CD47 is a protein that is normally present in healthy blood cells and prevents the body’s “clean-up” crews from removing these healthy cells from the circulation. When present, the CD47 protein provides a “do not eat me” signal to the clean-up cells, called macrophages. As normal blood cells age, CD47 disappears from their surface and along with other signals, this tells the macrophages that the cells must be removed, and so they are “eaten.” Many tumors have co-opted this mechanism to avoid the immune system. In the case of tumors and foreign invaders, being eaten by a macrophage is the first step of immune activation, so by displaying the “don’t eat me signal” on their surface, tumors are not only able to survive the danger of being eaten by macrophages (and thus eliminated), but also remain invisible to the rest of the immune system. One way to attack this mechanism of immune evasion is by adding drugs or compounds that prevent CD47 from disabling macrophages as part of cancer therapy. The hypothesis for this project was that CD47 blockade, in combination with an antibody
directed against lymphoma cells, would be safe and effective in a laboratory model of canine lymphoma.
This project was a collaboration among the ACCRP of the University of Minnesota, Stanford University, Novartis Animal Health (which was acquired by Elanco Animal Health during the course of our studies), and several companies that own the rights to the CD47 blockade compounds.
Our results showed that while neither CD47 blockade or antibodies against lymphoma cells were sufficient to control growth and dissemination of canine lymphoma by themselves, in combination, these products produced remarkable outcomes, completely eliminating the experimental tumors.
The combination of CD47 blockade with antibodies against lymphoma cells is now in advanced clinical trials in humans.
Determining the Correct Dosing for Anthracycline drug to Treat Canine Lymphoma (Dr. Alfred Legendre, University of Tennessee. AD198 is a new antrhacycline drug used in chemotherapy. This study will determine the best dose for dogs with lymphoma, and researchers will study how well AD 198 affects cancer cells so that an alternative treatment option can be available to owners and veterinarians.
Potential Drug Therapy for Treatment of Lymphoma (Dr. Laura Garrett, University of Illinois) using a novel compound called PAC-1 that has been shown to induce apoptosis (a normal process in which cells undergo programmed death.)
Immunotherapy and Genetic Studies
Several of the studies we have supported include:
CD47 Blockade to Enhance Adaptive Anti-tumor Immune Responses (Veterinary Student Katie Anderson, University of Minnesota, Dr. Jaime Modiano, and Dr. Matthew Mescher). The advantage of an immunological approach, to treat patients that have metastatic cancer, is that it uses the patient's own cells. This makes it easier to reach tumors that are inaccessible for conventional treatments, with fewer side effects. The success of this approach is tied to overcoming barriers that tumors build to evade the immune response. The objective of this study is to develop an approach whereby the patient's immune cells learn to recognize cancer cells at the primary site and eliminate renegade cancer cells before they spread to distant sites and establish metastases.
Effect of Tumor Microenvironment on Canine Myeloid Cells (Veterinary Student Scholar Jacob Wasserman, Ohio State University. Although chemotherapy has been the primary treatment of choice in human and veterinary oncology, chemotherapy is relatively untargeted and has numerous side effects. Stimulating the immune system to target tumor cells offers a potentially more effective and less toxic alternative to chemotherapy alone, and such cancer immunotherapy is being explored in canine and human cancer patients. In cancer, it is thought that myeloid cells, a type of cell derived from marrow, significantly contribute to the immunosuppression seen in cancer patients. This study was chosen to honor the memory of the Loeser's pet therapy dog, Brooke.
Studies we have supported include the following:
Investigating the Biology of Canine Met Mutations (Dr. Cheryl London, DVM, Ohio State University. Research has shown that mutations in a gene called Met contribute to the development of numerous types of cancer in humans and mice. This study is searching for genetic markers that will help better target cancer treatments and have identified two similar mutations in dogs, which have a high chance of developing cancer. The researchers are encouraged by their preliminary results with this inhibitor in several clinical cases of dogs diagnosed with osteosarcoma.
RNAi Delivery Vectors Target to Canine Tumors (Dr. D. Argyle, University of Edinburgh). This study ended in 2008. It identified a molecular target in cancer that is a near universal marker of malignancy. The study utilized RNA interference technology to develop a therapeutic strategy for cancers. They showed that the direct injection of these molecules may have an effect, albeit, not sustainable, in the cessation of cancer.