Immunotherapy Shows Benefit Against Metastatic Melanoma

A new and effective immune-based therapeutic approach for combating metastatic melanoma involves silencing the CD47 signaling protein recognized by specialized cells of the immune system, a recent study suggests.

CD47 is a cell surface protein known as a “don’t eat me,” signal that is overexpressed by metastatic melanomas, and helps cancer cells avoid being killed by the immune system, according to a study published in Cell Reports. CD271 is another cell surface protein previously shown to be expressed in melanoma initiating cells.

In the study, researchers hypothesized that metastatic melanomas rely on the overexpression of both CD47 and CD271 in order to trick the immune system and metastasize. To test this theory, researchers used specific blocking antibodies against CD47 to activate macrophage phagocytosis and CD271 to selectively target the most aggressive melanoma cell population.

The results of the study showed that when mice with human metastatic melanomas were treated with the antibody regimen, the simultaneous application of antibodies against CD47 and CD271 resulted in a near complete elimination of metastasis from all the organs. Researchers also discovered that the therapeutic effect was mediated by profound alteration of the microenvironment that surrounded the tumors, causing the immune cells to more effectively fight the cancer.

“Further research is needed to determine the full anti-metastatic properties of the dual CD47/CD271 antibody therapy and the safety of its application in human patients,” said lead researcher Alexander D. Boiko. “However, combining this therapy with other emerging treatments that also modulate the immune system represents a new approach that may offer increased benefit against metastatic melanomas. These are very exciting times for the cancer immunotherapy field and we are aiming to add an important component to this type of treatment, which will hopefully translate into a more effective outcome for patients.”