Animal Models for Childhood Cancer

When you hear the word cancer, you probably associate it with a family member, a friend, or even yourself. With more than 200 known types, cancer remains one of the most persistent challenges in medicine. Although chemotherapy and radiation therapy are often considered aggressive treatments for survival, scientists are working with modern technology and animal models to develop more targeted and effective therapies.

Cancer occurs when cells replicate abnormally, divide uncontrollably, and invade healthy tissue. These abnormal cells group together to form tumors that may spread throughout the body. In cancer research, animal models—including zebrafish, mice, dogs, and even horses—are useful for understanding how cancer develops, the role of certain genes and gene mutations, and in the creation and testing of drugs and other treatments. Mice are especially useful because they have many of the same biological features as humans and have over 80% of identical genetic components, according to the National Human Genome Research Institute.

Dr. Amy LeBlanc, a veterinary oncologist at the National Cancer Institute, studies cancer in both mice and dogs. Mouse models are “good at prioritizing and filtering what looks really promising while adding a level of rigor before testing [drug combinations] in dog models…to eliminate the one-off or the outlier,” she said.

LeBlanc’s research on dogs focuses on osteosarcoma., a “highly malignant and metastasizing” bone cancer common among older dogs. Osteosarcoma also occurs in humans—it’s a rare bone cancer in children and young adults. Dogs are a good animal model because they often share the same environment as humans, contain similar immune systems, and have a comparable natural medical history. LeBlanc’s discoveries may one day help both dogs and people.

Other scientists are relying on genetically engineered mice to test the effectiveness of cancer drugs. Professor Louis Chesler, a pediatric cancer researcher at The Institute of Cancer Research in London, is trying to develop new drugs for the two most common solid tumors in children—neuroblastoma, a nerve tumor, and medulloblastoma, a brain tumor. He conducted trials in mice using the drug momelotinib and found that it decreased tumor progression and increased survival rates. But in humans, the treatment didn’t work as well.

Dr. Sumana Shrestha, a member of Chesler’s team, is working on novel therapeutics that target the MYCN oncogene, a key driver in many childhood cancers. MYCN is vital for cell growth, division, and self-destruction of cells (apoptosis). When MYCN is overexpressed, tumors become more aggressive, she said. In studies using mice with brain tumors, she found that inactivating MYCN reduces tumor growth rates. In addition, she added, cancer cells need glucose and oxygen to survive. These key metabolic components interact with genes such as MYCN to drive tumor growth. Depriving tumors of those nutrients may impair cancer metabolism, starving the cancer and slowing its ability to divide and spread. Shrestha emphasized that there is no magic bullet for cancer, and that understanding the complex, interlinked processes of development, metabolism, and cell-cycle regulation is essential to improving outcomes for young patients. 

As the fight against cancer continues, LeBlanc, Chesler, Shrestha, and other scientists will continue to rely on modern technology and animal models in their quest for better and more targeted cancer treatments.