What are kinase inhibitors and what do they do?
A. We were interested in cyclin-dependent kinase inhibitors because it became clear that they would very likely be tumor suppressors. Kinases are enzymes that modify protein activity by phosphorylation, and cyclin-dependent kinases regulate the cell cycle. If you can inhibit those kinases, you can interfere with the cell cycle. Interrupting the cell cycle is strategically important in cancer therapy. When it was discovered that cyclin-dependent kinase inhibitors could block the progression of the cell cycle, they became candidates for potential tumor suppressor genes. To find out if they were tumor suppressors, we analyzed mutations in cancers from different patients. The normal cell had an unchanged copy of the gene, but the tumor suppressor gene was altered in the cancer cell because of various mutations. Q. When did you become interested in vitamin D? A. When I went to Cedars-Sinai Medical Center, I worked with Phillip Koeffler, a hematologist/oncologist who has worked on both leuke
