Dr. Janice Dutcher, MD is Professor of Medicine at New York Medical College and Associate Director for Clinical Affairs at Our Lady of Mercy Cancer Center, Bronx, NY. She is a founding member of the Cytokine Working Group and served as Chair of the FDA Oncologic Drug Advisory Committee. She is actively involved in patient care and clinical research in renal cell cancer, and is a strong advocate for research into the etiology and treatment of RCC.
Normal epithelial cells (such as those lining blood vessels) are very stable and replicate one time in five years. Those associated with tumors replicate one time in less than a week. The growth process relies on a complex chain of proteins and receptors to "send" and "receive" signals. Mediation of cell growth by interfering with receptors is a common theme in cancer therapy research. Tyrosine kinases target receptors on the outside of the cell membrane or intracellular. Herceptin, used in breast cancer, is for the external receptors. Gleevec, a breakthrough drug in Chronic Myleogenous Leukemia, and a rare cancer called Gastrointestinal Stromal Tumor, is intracellular.
A type of compound has been developed which interferes with production of proteins in the growth chain. It is called a hammerhead ribozyme. It mimics a protein found within the cell, except that it contains a break in the amino acid chain which causes only segments of the original protein to be replicated. There is a loop of amino acids at the cleavage site for stability which is called a stem loop. A specific one designed for anti-VEGFR-1 receptor is called Angiozyme. (VEGF is vascular epithelial growth factor which is a protein involved in initiating new vascular growth to supply growing tumors.)
Angiozyme is showing a positive effect in mice and is safe at high doses.