LIGHT is an immune-stimulating chemical messenger previously found to have low levels of expression in patients with colon cancer metastases. The results are published in Cancer Research<\/i>.<\/p>\n
Colon cancer is the second-leading cause of cancer-related death in the U.S. and, despite advances in treatment, long-term survival of patients with liver metastases is rare.<\/p>\n
\u201cFor most patients with colon cancer that has spread to the liver, current treatments are palliative and not curative,\u201d says Dr. Ajay Maker, associate professor of surgery in the UIC College of Medicine and corresponding author on the paper. \u201cAnd while studies have suggested that immunotherapy may be a promising approach for advanced cancers, the use of such treatments for advanced gastrointestinal metastases have not yet been very successful.\u201d<\/p>\n
Maker, a surgical oncologist, says that this study is exciting because it looks at an immunotherapy intervention for a previously unresponsive gastrointestinal cancer. The intervention, he says, essentially trains the immune system to recognize and attack the tumor, and to protect against additional tumor formation\u2013a significant issue in colon cancer.<\/p>\n
Maker and his colleagues established colon cancer tumors in a mouse model, in which the animals had an intact and unedited immune system. Once tumors were sizable, the mice were randomized into two groups\u2013one group had the cytokine LIGHT turned on in the tumors, and the other served as a control group for comparison.<\/p>\n
Tumors exposed to LIGHT showed an influx of T-cells that resulted in rapid and sustained diminishment in size, even after expression of the cytokine stopped. In mice with liver metastases, expression of LIGHT similarly provoked a potent immune response that resulted in a significant decrease in tumor burden.<\/p>\n
\u201cWe demonstrated that delivery of a therapeutic immune-stimulating cytokine caused T-cells to traffic to tumors and to become activated tumor-killing cells,\u201d Maker said. \u201cThis activity is especially exciting because it resulted in a profound anti-tumor immune response without any other chemotherapy or intervention. The treatment manipulates our natural defenses to fight off the tumor in the same way it has been trained to attack other foreign invaders in our body.\u201d<\/p>\n
\u201cNot only did we find that LIGHT expression promoted tumor regression, upon further study we also identified the specific type of T-cell \u2014 CD8 \u2014 that was responsible for shrinking the tumor,\u201d Maker said. \u201cThese findings are powerful and have great clinical potential.\u201d<\/p>\n