Examination of the Effects of Cannabidiol on Canine Neoplastic Cell Apoptosis/Autophagy and Potential for Chemotherapy Resistance or Sensitivity

Currently the use of cannabidiol (CBD) rich extracts for canine oncology patients is common, yet there is no data in canine oncology regarding the effects of CBD on canine cancer cells. Oncologists are wary of CBD use in their patients due to a lack of knowledge regarding the effects of CBD during chemotherapy.

Initial studies on cytotoxicity by the research team show that CBD has cytotoxic activity on a variety of canine cancer cell lines at modest concentrations in the laboratory. These effects cause apoptosis, or programmed cell death, within a very short time frame, suggesting a discrete mechanism.

The objective of this study is two-fold; 1) to determine if co-treatment of cancer cells with a common chemotherapeutic (doxorubicin) and CBD at varying concentrations affects chemotherapeutic cytotoxicity, and 2) to examine the molecular framework of the cell death response looking at the most commonly implicated pathways targeted in canine cancer treatment, including mechanisms of cell signaling and autophagy (removal of damaged cells).

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02643-A

RESEARCHERS

Joesph J. Wakshlag, DVM, PhD; University of Florida
Amount: $2,500

Clinical Trial for Evaluation of Propranolol and Doxorubicin in the Treatment of Canine Hemangiosarcoma

Canine hemangiosarcoma is a largely incurable cancer in dogs, and treatment approaches to improve outcomes have remained relatively stagnant over the past few decades. Treatment remains a challenge partly because the cancer is frequently detected at an advanced stage and because these tumors are often resistant to chemotherapies. Recently published reports showed that propranolol, a drug used to treat heart disease in humans and dogs, substantially increased the survival time of human angiosarcoma patients when used in combination with standard of care treatments. Propranolol was also shown to sensitize hemangiosarcoma cells to doxorubicin, providing a more effective way to kill tumor cells. Because angiosarcoma is strikingly similar to canine hemangiosarcoma, this multi-institutional clinical trial has been designed to determine the efficacy of propranolol in dogs with hemangiosarcoma when used in combination with surgery and chemotherapy.

The main goal of the study is to establish whether propranolol in combination with doxorubicin following surgery improves outcomes for dogs when compared to the use of chemotherapy and surgery alone. The investigators will also evaluate the plasma concentrations of propranolol achieved during dosing to assess whether the levels of propranolol correlate to survival times. If successful, the findings from this approach will be rapidly conveyed to the veterinary community, and the guidelines provided to clinicians for the use of propranolol and doxorubicin for the treatment of canine hemangiosarcoma.

Co-investigators: David R. Brown, PhD, University of Minnesota; Michael O. Childress, DVM, MS, Purdue University; Jennifer Mahoney, DVM and Pascale Salah, DVM, University of Pennsylvania

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02534

RESEARCHERS

Erin Dickerson, PhD and Brian Husbands, DVM; University of Minnesota
Amount: $10,000

Targeting the Cancer Epigenome: The Effect of Specific Histone Lysine Methyltransferase Inhibition in Canine B-Cell Lymphoma

Canine lymphoma is one of the most common cancers in dogs. While some breeds appear more at risk than others, all can be affected. Although it is often treatable, canine lymphoma can rarely be cured. A continued understanding of the mechanisms causing lymphoma in dogs and identification of novel therapies are needed to improve survival in dogs with lymphoma.

One area of research that has been actively explored and provided exciting breakthroughs for human lymphoma is epigenetics, or alterations in how genes are turned on and off independent of the DNA sequence. One way in which this occurs is due to modifications of the proteins that interact with DNA called histones. Various modifications to these histones can result in genes being turned on or off, leading to the development of cancer. One particular enzyme that modifies histones, EZH2, has been found to play a role in some human lymphomas. However, this has been unexplored in canine lymphoma. Given the striking similarities between human and canine lymphoma, the objective of this work is to characterize the function and role of EZH2 in canine lymphoma.

The investigators will utilize an EZH2 inhibitor to study EZH2 in canine lymphoma cells. The information obtained from this study will help guide the future development of this targeted inhibitor for use as a novel therapy to treat canine lymphoma.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02309

RESEARCHERS

Angela McCleary-Wheeler, DVM, PhD; University of Missouri, Columbia
Amount: $5,000

Precision Medicine for Canine Lymphoma

The clinical response of dogs with lymphoma to multi-agent chemotherapy is highly variable. Although up to 85% of dogs respond initially, some relapse within weeks, while others enjoy remission times of two years. This heterogeneity in clinical response is in part explained by the recognition that “lymphoma” is not a single disease entity, but consists of different subtypes that can be characterized on a molecular level by mutations in specific genes.

As in human medicine, it follows that different lymphoma subtypes, driven by different molecular mechanisms, may respond better to therapies that are specifically selected to inhibit the driver mechanisms within that patient’s tumor. Recent work using sophisticated genetic sequencing tools (next-generation sequencing (NGS)) has begun to shed light on the different molecular subtypes of canine B cell lymphoma, and specific therapies aimed at targeting patient-specific driver genes and pathways are being developed.

To enable targeted therapies to move into the clinic, a personalized diagnostic tool must be developed that can rapidly and cost-effectively determine the mutational profile of a patient’s cancer allowing selection of the most effective drug for that patient. The investigators aim to develop a NGS diagnostic test that can be employed on standard biopsy samples to identify molecular drivers of a patient’s lymphoma (personalized diagnostics), enabling the most appropriate targeted therapy to be selected for that patient. In addition, they aim to determine whether specific mutational profiles within canine lymphoma identified by their NGS panel, are predictive of clinical outcome.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02441

RESEARCHERS

Nicola Mason, BVetMed, PhD
Trustees of the University of Pennsylvania
Amount: $5,000

Tumor-permissive Collagen Signatures in Canine Mammary Gland Tumors: Development of Prognostic Markers and Targeted Therapies for Improved Outcomes

Mammary gland tumors (MGT) are the most common malignancies in intact female dogs, and the resulting premature death and morbidity in this sub-population of dogs represents a significant health problem. While genetic alterations within tumor cells can promote their uncontrolled growth and ability to spread to distant sites, recent work indicates that normal, non-malignant cells and extracellular matrix (ECM) within the surrounding tumor stroma also regulate the growth and spread of cancer.

The investigators have identified cancer-associated stromal (collagen) signatures in canine MGT biopsy samples that predict clinical outcome better than commonly used markers. These predictive markers may improve the veterinary oncologist’s ability to accurately predict which dogs truly need aggressive treatment from those that do not. Notably, their laboratories have shown that inhibition of a collagen-degrading enzyme (Fibroblast Activation Protein (FAP)) and increasing a tumor suppressive collagen (type III collagen (Col3)) prevent the formation of these tumor-inciting signatures in other species (mouse and human). This work suggests that if these novel targets can suppress tumor-permissive collagen signatures in the dog, we can treat canine MGT more effectively.

The goals of this project are 1) to identify additional collagen signatures which predict clinical outcome in dogs, 2) determine how they direct tumor cell behavior and 3) develop therapies that prevent formation of tumor-inciting collagen signatures in canine MGT. Based on the investigators’ published and preliminary data, they predict that identifying and targeting tumor-inciting collagen signatures will lead to improvements in both diagnosis and treatment of dogs with malignant MGT.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02489

RESEARCHERS

Susan Volk, VMD PhD
University of Pennsylvania
Amount: $5,000

Prevalence of Bartonella spp. Infection in Dogs with Cardiac and Splenic Hemangiosarcomas within and between Geographic Locations

Splenic masses comprise ~50% of all canine splenic disease. Despite advances in imaging and pathologic definition, the etiology and medical relevance of splenic lesions in dogs are often ambiguous. While some splenic tumors are benign, approximately two-thirds are highly malignant and carry a poor prognosis. Hemangiosarcoma (HSA) accounts for the majority of canine malignant splenic tumors and occurs in many large dog breeds, including mixed breeds.A less common site of HSA localization is the heart (cardiac HSA). Risk factors for both cardiac and splenic HSA remain unclear, confounding development of preventative strategies.

The investigators recently reported a high prevalence of species of the bacterial genus Bartonella in dogs with HSA from North Carolina, suggesting a potential role in the initiation and/or progression of this cancer. Bartonella species exist worldwide and are transmitted by blood-sucking arthropods (e.g. ticks, fleas) and their presence in splenic tissue could potentially be explained by the fact that the spleen is primarily responsible for removal of blood-borne parasites from the systemic circulation.

The investigators will perform a comprehensive examination of the potential association between Bartonella infection and HSA by comparing the prevalence of Bartonella DNA in tumor and blood samples from both splenic and cardiac HSA cases, and also within and between distant geographical locations in the US. Ultimately, demonstration of a robust association between Bartonella infection and the development of HSA may lead to new opportunities for improved diagnosis, treatment and prevention of this devastating cancer.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02519

RESEARCHERS

Edward Breitschwerdt, DVM
North Carolina State University Office of Sponsored Programs
Amount: $10,000 in 2018, $10,000 in 2019

Investigating Cancers and Exposure to Environmental Chemicals

Scientific Title: Detoxification of Environmental Carcinogens by Glutathione-Stransferases in Dogs

Summary: Researchers will find out how the dog’s body breaks down common environmental chemicals that have been linked to cancers in humans.

Description: When dogs or humans are exposed to toxic chemicals in the environment, they use glutathione-S-transferase (GST) enzymes to break down and neutralize those chemicals. When GST enzymes are not working, toxic chemicals sometimes lead to cancers such as lymphoma or bladder cancer. Researchers will test how well four major GST dog enzymes can neutralize several common environmental chemicals, including those found in tobacco smoke and yard products.

Results will provide a clearer understanding of whether individual dogs with low-acting GSTs may be sensitive to specific chemicals and, as a result, more susceptible to developing environmentally associated cancers.

Co-sponsored with the Morris Animal Foundation, Grant Number: D18CA-070

RESEARCHERS

Dr. Lauren A Trepanier
University of Wisconsin-Madison
Amount: $10,000

Harnessing a Dog’s Own Immune System to Kill Lymphoma Tumor Cells

Lymphoma is the most common malignancy of dogs representing up to 25% of diagnosed cancers. Dogs often develop an aggressive form of lymphoma that is rarely curable, with most unfortunately succumbing to disease within 12 months of diagnosis despite best available chemotherapies.

Dr. Wilson will develop a new treatment to re-train the dog’s own immune system to attack the most common type of canine lymphoma, B-cell lymphoma. In order to accomplish this they will obtain a small number of circulating white blood cells, called T cells, from the blood of affected dogs and insert a gene that will cause the T cell to express a receptor which recognizes the tumor “fingerprint”. After docking with the lymphoma, the T cell will be triggered to mount an immune response against the tumor cells with the specific fingerprint.

This therapy could be used alone or in combination with chemotherapy. Their preliminary data demonstrate that it is possible to genetically modify T cells. Further, they have been able to successfully harvest and grow T cells in the laboratory and return them safely to the dog. These infused cells can be found in the blood and tumor weeks after infusion, showing that it is possible for these cells to survive in the dog. If successful this study will be the first to develop an “in-dog” T-cell therapy targeting a tumor that has historically thought to be untreatable.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 01418

RESEARCHERS

Heather M Wilson-Robles DVM
Texas A&M Research Foundation
Amount: $2,000

Identification of genetic mutations in anal sac carcinoma in English Cocker Spaniels

English Cocker Spaniels (ECSs) are about 7 times more likely than other dog breeds to develop anal sac carcinoma (ASC). Hence, there appears to be a genetic basis for this disease development in ECSs.

The investigators will sequence the genomes and transcriptomes of blood and ASC tumor samples collected from ECS dogs across the US. The samples will be studied alongside the pedigree information and medical records.

Using dog-human comparative genomics and oncology strategy for cancer-causative mutation discovery, successful identification of mutations in ASC development in ECSs may lead to the development of genetic tests of this aggressive disease in ECSs and yield targets for therapeutic intervention.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02455-A

RESEARCHERS

Shaying Zhao PhD
University of Georgia
Amount: $2,000

Genetic and Environmental Risk for Lymphoma in Boxer Dogs

Lymphoma is a fatal cancer of the blood cells that can occur in any dog. Lymphoma is more common in Boxers, Golden Retrievers, and several other purebreds, which suggests involvement of inherited genes. Recent research has focused on gene mutations in the tumors of dogs with lymphoma. However, we do not understand why these mutations accumulate in certain dogs, and this understanding is essential for disease prevention.

Canine lymphoma resembles Non-Hodgkin lymphoma (NHL) in humans, which is more common in industrialized countries and is associated with chemicals found in tobacco smoke, certain household products, pesticides, herbicides, and fungicides. Glutathione-S-transferases (GSTs) are enzymes that can break down toxic chemicals in the body and prevent tumor mutations. Inherited gene defects in the 3 major GST enzymes, GST-theta, GST-pi and GST-mu, each increase NHL risk, and simultaneous defects in more than one enzyme further increase NHL risk.

The investigators have characterized two GST-theta enzymes in dogs, and both have defective gene variants. So far, their findings suggest one variant is a risk factor for lymphoma in dogs of varying breeds. However, the genes for canine GST-pi and GST-mu enzymes have not yet been explored.

This research will determine whether defective GST genes along with certain household and yard chemicals are associated with lymphoma in dogs, with a focus on the high-risk Boxer breed. The overall goal of this study is to identify combinations of genes and environmental chemicals that contribute to the development of lymphoma in dogs, so that better cancer prevention strategies can be developed.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02318

RESEARCHERS

Dr. Lauren A Trepanier, DVM PhD
University of Wisconsin, Madison
Amount: $10,000