Discovery presents possible therapeutic targets for inoperable cancers
Recently published in the prestigious journal Nature, Dr. Sabine Cordes and her team of researchers at Mount Sinai’s Lunenfeld-Tanenbaum Research Institute have established a connection between a gene named Gumby and blood vessel growth. The new discovery provides hope that, in addition to other treatments for cancer, the Gumby gene can become an attractive target for drug therapies against certain cancers by potentially restricting blood flow to tumours that are inoperable, such as in the brain.
The Gumby gene affects blood vessels that form the blood brain barrier, which regulates the supply of essential nutrients into the brain and keeps unwanted molecules out. If the Gumby gene is defective, it can impair the development and function of blood vessels, causing a blockage in blood flow to the brain, which can also lead to mental health disorders.
“This new finding is exciting for us because it means that the Gumby gene can be modified to enhance or limit blood vessel growth in a number of illnesses,” explains Dr. Sabine Cordes, Senior Investigator at the Lunenfeld-Tanenbaum Research Institute and Associate Professor, Department of Molecular Genetics and the Institute of Medical Sciences at University of Toronto.
In their study, Mount Sinai researchers found that Gumby plays a significant role in cellular communication systems by acting as a local “mailman”. Once cells receive an external signal, such as one required for blood vessel growth, cells rapidly send proteins to specific locations within them and thereby change their shape and behavior in order to fulfill the message. Gumby contributes to this shape and behaviour change by selectively removing a tag called ubiquitin, a protein which cells use as a “zipcode” to direct other proteins to places where they are needed. A defective, form of Gumby disrupts this communication system, ultimately leading to impaired blood vessel growth.
For the first time, Dr. Cordes and her team may have also discovered potential therapeutic targets for Cri du chat syndrome, a disorder that affects approximately 1 in 20,000 children due to the loss of multiple genes on chromosome 5. Infants with this condition often have a high-pitched cry that sounds similar to that of a cat, and is characterized by intellectual disability, delayed development, and facial anomalies. Gumby is found on a region of chromosome 5 associated with mental retardation and craniofacial anomalies in Cri du chat patients.
To better understand how the Gumby gene works and to ultimately help improve diagnoses and treatments for patients affected by mutations in this gene, Dr. Cordes’ team collaborated with researchers in Dr. Frank Sicheri’s and Dr. Anne-Claude Gingras’ labs at the Lunenfeld-Tanenbaum Research Institute, as well as with Dr. Yoichi Gondo and Dr. Ryutaro Fukumura from RIKEN, a large natural sciences research institute in Japan.
The work published in this Nature paper was also made possible through generous funding by the EJLB Foundation and a generous gift from Henry and Esther Bernick, donors to Mount Sinai Hospital.