Trigger for Bone Cancer Identified

Scientists have possibly found the protein behind osteosarcoma.
By JoAnna Lou, March 2015
UW-Madison School of Veterinary Medicine intern Kathleen Tsimbas checks on Yurtie, a canine cancer patient, in the UW Veterinary Care oncology ward.

With so many dogs I know affected by cancer, I'm always excited to learn about new breakthroughs in the search for a cure. The latest research out of the University of Wisconsin-Madison School of Veterinary Medicine is an important one, as they may have identified the biological mechanism that gives some cancer cells the ability to form tumors in dogs.

Scientists at the school were interested in why only some cells generate tumors. What they found was a connection between the increased expression of a particular gene in tumor cells and canine bone cancer.

The study looked at cell lines generated from dogs with osteosarcoma, a common bone cancer that also affects people. After removing tumors from the canine participants, the cells were grown in a lab and transplanted into mice. The researchers then looked to see which lines developed tumors and which did not, and the differences between them.

The scientists identified several hundred genes that expressed differently between the tumor-forming and nontumor-forming cell lines. One protein in particular, called frizzled-6, was present at levels eight times higher in cells that formed tumors. Proteins and RNA, like frizzled-6, are responsible for many vital cellular functions, like receiving information and activating pathways that regulate growth. When these pathways go awry, they may contribute to the development of tumors.

Though a preliminary association has been made, it's not clear what role frizzled-6 plays. It's possible that the frizzled-6 expression may be inhibiting a signaling pathway that contributes to the formation of tumor-initiating cells.

Next the researchers want to better understand the findings. Does frizzled-6 serve as a marker of a more aggressive disease? Will identifying the protein improve the accuracy of prognoses? The veterinary school plans to continue the study in order to answer these questions, in addition to expanding the research to human cancer patients. They'd like to confirm that frizzled-6 is truly what gives these cells the ability to form new tumors, or if it's possible that it's part of a combination of multiple genes that lead to tumor formation.

If they can prove that frizzled-6 is behind the tumor-forming cells, the protein may provide oncologists with another target for therapy which would improve outcomes for cancer patients, both canine and human.

JoAnna Lou is a New York City-based researcher, writer and agility enthusiast.