Destroying normal melanocytes prompts attack on melanomas

Work in mice indicates that inflammatory killing of normal cells can induce immune responses that will eliminate established tumors, researchers report. They note that this approach “obviates the need to identify tumor antigens and does not require complex isolation of tumor cells or their derivatives.”

As lead investigator Dr. Robert G. Vile told Reuters Health, the findings “show, for the first time to our knowledge, that intentional destruction of normal tissue can be used to raise T cell autoimmune responses which can lead to clearing tumors derived from the same tissue type.”As described in the August 1st advance online publication of Nature Biotechnology, Dr. Vile of the Mayo Clinic in Rochester, Minnesota and colleagues used intradermal plasmid DNA injections to deliver a transcriptionally cytotoxic gene targeted to normal melanocytes, along with hsp70, into mice.This induced inflammatory killing of normal melanocytes. It also induced a CD8+ T-cell dependent antigen-specific response that eradicated established systemic B16 tumors.Moreover, Dr. Vile added, “we also showed that the autoimmune response is rapidly suppressed. This is clinically important because it means that it may be possible to generate transient autoimmune responses which can attack tumors, but which do not lead to long-term autoimmune disease.”(Source: Nat Biotechnol 2004: Reuters Health: David Douglas: Oncolink: August 2004)