by Edwin Brodsky, DVM, Diplomate ACVIM (Oncology)
Recently, a great deal of research has been done in both normal and cancerous cells regarding the signals involved in cell growth, differentiation and survival. Normal cells receive signals from outside the cell via molecules called growth factors. These growth factors bind to growth factor receptors on the cell membrane. The receptors become activated and start a downstream signaling cascade inside the cell which eventually reaches the nucleus where the signal exerts its influence on the cell telling it to grow, divide, etc. Many different enzymes are involved in this signaling cascade. It has been found that many components (enzymes) of this signaling pathway become dysregulated in cancer cells via mutation, over expression and other mechanisms, leading to inappropriate cell activation, growth, division and survival. These enzymes provide a target for therapy when treating cancer.
One class of signaling enzymes are called tyrosine kinases. Tyrosine kinases can be classified into two categories – receptor tyrosine kinases and non-receptor tyrosine kinases. The receptor tyrosine kinases function as growth factor receptors and transmit growth signals from outside the cell to inside the cell. The receptor tyrosine kinases provide attractive targets for therapy. By using drugs that block the activation of the receptor tyrosine kinases, we are able to block there downstream signaling pathways and thus the stimulation for cell growth, division and survival.
Edwin Brodsky, DVM, Diplomate ACVIM (Oncology)
Veterinary Medical Center of Long Island
75 Sunrise Highway
West Islip, New York 11795
(631) 587-0800; fax (631) 587-2006