One of the mysteries surrounding prostate cancer has been its seeming predilection for bone. Is this because other tissues are not amenable to its advances or does bone send out some sort of homing signal that draws the metastasizing cells? Scientists at the National Institute of Dental and Craniofacial Research (NIDCR) now have convincing evidence that a substance in bone not only attracts the prostate cancer cells, but stimulates them to become invasive. This finding has important implications for the discovery and development of agents that might be used in the treatment of prostate cancer and other cancers that spread to bone.
Prostate cancer is the second leading cause of cancer deaths in men from both Europe and the United States. At the time of diagnosis, over 70 percent of the cases have metastasized to the pelvic lymph nodes. From there, cancerous cells show a high propensity for invading bone in the pelvis and vertebra of the lower back.
The question has been why bone rather than nearby organs like kidney, liver, or even lung. One theory has been coined "seed and soil," which likens cancer cells to seeds drifting in the wind and landing at random on different types of soil--putting down roots only where the local conditions allow. Another theory portrays cancer more like a predatory animal that is drawn by the trail of its favorite prey.
Drs. Karin Jacob and Hynda Kleinman from NIDCR's Craniofacial Developmental Biology and Regeneration Branch led an international research team to determine if there was a specific factor in bone that acts as an attractant for prostate and possibly other bone-seeking cancers, such as breast cancer. By studying the reaction of prostate cancer cells to various solutions of tissue extract, they found that a bone protein caused the cells to aggressively migrate to the bone extract. The study appears in the September 1 issue of Cancer Research.
The investigators used a technique developed by Dr. Klein
Contact: Wayne Little
NIH/National Institute of Dental and Craniofacial Research