Researchers at the University of Wisconsin-Madison School of Veterinary Medicine have identified the biological mechanism that may give some cancer cells the ability to form tumors in dogs.
Yurtie, a canine cancer patient, in the UW Veterinary Care oncology ward.
Photo: Nik Hawkins
The recent study uncovered an association between the increased expression of a particular gene in tumor cells and more aggressive behavior in a form of canine bone cancer. It may also have implications for human cancers by detailing a new pathway for tumor formation.
The findings of the research have been published in the journal Veterinary and Comparative Oncology and may eventually provide oncologists with another target for therapy and improve outcomes for canine patients with the disease.
The researchers examined cell lines generated from dogs with osteosarcoma, a common bone cancer that also affects people, with the intent of uncovering why only some cells generate tumors. After the dogs underwent tumor-removal surgery, cells from the tumors were grown in the lab.
This led to six different cancer cell lines, which were then transplanted into mice. The researchers then looked to see which lines developed tumors and which did not and studied the differences between them.
“We found several hundred genes that expressed differently between the tumor-forming and nontumor-forming cell lines,” said Timothy Stein, an assistant professor of oncology. However, one protein called frizzled-6 was present at levels eight times higher in cells that formed tumors.
“It’s exciting because it’s kind of uncharted territory,” says Stein “While we need more research to know for sure, it’s possible that frizzled-6 expression may be inhibiting a particular signaling pathway and contributing to the formation of tumor-initiating cells.”
The team’s genetic research will continue on dogs and be extended to humans.
Source: University of Wisconsin-Madison media release
Posted in dog care, research
Tagged bone cancer, cancer, cancer cell, cancer cells, genetic, oncology, osteosarcoma, tumors in dogs, University of Wisconsin, Veterinary and Comparative Oncology
There is a form of cancer treatment called immunotherapy, where antibodies inhibit tumor growth. Until now, such therapy wasn’t available for dogs. A research team at Messerli Research Institute of the Vetmeduni Vienna, the Medical University of Vienna and the University of Vienna have now developed antibodies to treat cancer in dogs.
The newly developed antibody brings hope for dogs. (Photo by: Michael Bernkopf / Vetmeduni Vienna)
Since cancer cells bear very specific antigens on the surface, the corresponding antibodies bind to these molecules and inhibit tumor growth. A destructive signal sent by the antibody to the inside of the cancer cell initiates its death. In a second mechanism, the immune system of the patient also destroys the “marked” tumor in a more efficient way.
Josef Singer and Judith Fazekas, both lead authors of the study, discovered that a receptor frequently found on human tumor cells (epidermal growth factor receptor or EGFR) is nearly 100 percent 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 say. The binding site of the antibody to EGFR in man and dogs differs only in respect of four amino acids.
The head of the study, Professor Erika Jensen-Jarolim, explains as follows: “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.”
The newly developed antibody provides an additional benefit for dogs. As in human medicine, antibodies can be coupled with signal molecules. When the antibody binds to a cancer cell in the organism, the coupled antibody – in this case a radioactive isotope – can be rendered visible and is thus able to show where tumors and even metastases are located. When the selected isotope also contributes to the decay of cancer cells, the approach is known as “theranostics” (therapy and diagnostics).
In veterinary medicine, immunotherapy will be employed for the treatment of mammary ridge cancer (milk line cancer) in dogs. It may also be used as part of a combination therapy.
The team have published their study results in the journal Molecular Cancer Therapeutics.
Source: Vetmeduni Vienna media release
Scientists have sequenced the genome of the world’s oldest continuously surviving cancer, a transmissible genital cancer that affects dogs.
Credit: © Melinda Nagy / Fotolia
The cancer, which causes grotesque genital tumours in dogs around the world, first arose in a single dog that lived about 11,000 years ago. The cancer survived after the death of this dog by the transfer of its cancer cells to other dogs during mating.
Analysis of the genetic variants in the genome revealed that the dog may have resembled an Alaskan Malamute or Husky. It probably had a short, straight coat that was coloured either grey/brown or black. Its genetic sequence could not determine if this dog was a male or a female, but did indicate that it was a relatively inbred individual.
The genome has over 2 million mutations; the research team used one type of mutation, known to accumulate steadily over time, as a ‘molecular clock.’ This led to the estimate that the cancer first arose 11,000 years ago.
“The genome of this remarkable long-lived cancer has demonstrated that, given the right conditions, cancers can continue to survive for more than 10,000 years despite the accumulation of millions of mutations”, says Dr Elizabeth Murchison, first author from the Wellcome Trust Sanger Institute and the University of Cambridge.
Transmissible cancers are very rare in nature. Apart from the dog transmissible cancer, the only other known naturally occurring transmissible cancer is an aggressive transmissible facial cancer in Tasmanian devils that is spread by biting.
Source: Wellcome Trust media statement