London: For the first time, scientists have developed antibodies to treat cancer in dogs. As in humans, cancers in dogs have complex causes. The interaction of the environment, food, and genetic disposition are the most well known factors. Today nearly all methods of human medicine are basically available for dogs with cancer, but this was not true of cancer immunotherapy so far.
Cancer immunotherapy is the treatment of tumours by the use of antibodies and has been established and used very successfully in human medicine for about 20 years. Since cancer cells bear very specific antigens on the surface, the corresponding antibodies bind to these molecules and thus inhibit tumour growth.
Scientists at the inter-university Messerli Research Institute of the Vetmeduni Vienna, the Medical University of Vienna, and the University of Vienna discovered that a receptor frequently found on human tumour cells (epidermal growth factor receptor or EGFR) is nearly 100 per cent identical with the EGF receptor in dogs. In human medicine EGFR is frequently used as the target of cancer immunotherapy because many cancer cells bear this receptor on their surface. The so-called anti-EGFR antibody binds to cancer cells and thus triggers the destruction of the cells.
"Due to the high similarity of the receptor in humans and dogs, this type of therapy should work well in dogs too," the scientists said. The binding site of the antibody to EGFR in man and dogs differs only in respect of four amino acids, they said. To ensure best possible binding of the antibody to cancer cells in dogs, researchers trimmed the human antibody in the laboratory. In experiments on dog cancer cells in the laboratory it was found that the newly developed antibodies did, in fact, bind to canine cancer cells with greater specificity.
"We expect dogs to tolerate these anti-cancer antibodies well. This will be investigated in clinical studies in the future and is expected to greatly improve the treatment as well as the diagnosis of cancer in dogs," said Professor Erika Jensen-Jarolim who headed the study. The research was published in the journal Molecular Cancer Therapeutics.
