pparently, I am a dog person. It might actually be truer to say that I like all animals, but I’m sure that if you were able to ask my dog her opinion, she would tell you: I am a dog person. As a product of my culture, I spend an inordinate amount of money and time on my dog. Studies show that Americans spent over $60 Billion on their pets in 2013, with slightly more than half of that on just their dogs alone. Specifically, nearly 46 million households have provided a comfortable, all-inclusive, resort-like home for nearly 80 million dogs in the United States in 2013. Those trends have been steadily increasing for years and do not look to taper off anytime soon.

As we improve the quality of life for our dogs, their life expectancy has increased, just like ours did in the throughout the 20th century. It’s no surprise, then, that dogs are seeing an increase in cancer rates, partially due to their extended life expectancies…again, similar to our own history of complications with increased life expectancy. One of the most common forms of bone cancer in dogs is called Osteosarcoma or OSA. Its prevalence most often strikes in larger, and older, dogs and accounts for about 85% of canine skeletal tumors. OSA occurs often around the leg joints and treatment usually involves amputation followed by chemotherapy. However, even with treatment, the prognosis is very poor. Approximately 90% of dogs succumb to metastasis and the average life expectancy, post treatment, is only 6 months. Tragically, there is just a 50% chance of surviving a year and but a 25% chance of our best friends surviving beyond that point.

As with all cancers, the key to survival is earlier detection and earlier treatment/therapy. But it’s not as if our beloved pets can tell us when something hurts or just doesn't feel right. More often than not, they play through the pain, ignoring all but the worst of their injuries and ailments. And let’s face it, most of us pay less attention to the small clues they do give us than we should, further complicating the job of our veterinarians. To help address this tragic problem, a group from the College of Veterinary Medicine in Oregon, began the introductory process of identifying and defining the surface-exposed proteins (SEP) of OSA cancerous cells.

Milan Milovancev et al. used a biotinylation/streptavidin enrichment process to label and identify with Mass Spectrometry more than 100 putative SEP candidates from verified OSA cell lines as compared to normal osteoblasts. Utilizing the strength of the biotin-streptavidin association, Milovancev’s group biotinylated the surface-exposed proteins in the cells, lysed the cells to release the proteins and separated the biotinylated proteins using streptavidin-labeled beads…simple, clean and efficient.

Of course the enrichment process, by its own method, skews the quantification of the protein levels in the tumor cells. But the purpose of this study was only to find putative candidates, which can then be further studied in depth at a later time. To that end, Milovancev’s group set out to validate these initial results with secondary identification methods, such as RT-PCR, Western Blots and Immunocytochemistry. The follow up results mostly (but not completely) verified the results of the enrichment/MS identification method, meaning that while the system will do what it’s supposed to in general, Milovancev is just going to work harder to achieve a future, better refinement of the procedure.

As a dog person, I (and my dog) wish him well.

Milovancev, M., Hilgart-Martiszus, I., McNamara, M. J., Goodall, C. P., Seguin, B., Bracha, S., & Wickramasekara, S. I. (2013). Comparative analysis of the surface exposed proteome of two canine osteosarcoma cell lines and normal canine osteoblasts. BMC Veterinary Research, 9, 116.

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