Macrophage Therapy: Strategy to Slow Tumor Growth

As cancer causes the number of cells in the body to change and grow at an uncontrollable rate, a new study focuses on the depletion of these cells in mice via several experiments.

According to scientists at the University of Washington, they worked to develop a strategy in which would slow the tumor growth and prolong the survival in mice with cancer via targeting and destroying the cells that harm the immune system in cancer.

 "We're really enthusiastic about these results because they suggest an alternative drug target that could be synergistic with current treatments," co-author Suzie Pun saidvia a press release, a UW associate professor of bioengineering.

As the immune system normally works to eliminate abnormal cells, the cells known as macrophages are a type of immune cells that can be transformed into cancerous tissues. For instance, when inside a tumor, these cells may switch from helping the immune system to suppressing the body's immunity to cancer.

The team took a closer look at trying to eliminate the cancer-supporting macrophages in mouse tumors in order to predict the best strategy that could be used alongside various treatments, including chemotherapy.

The study concludes with the following, via a the release: "In this study, UW bioengineering doctoral student Maryelise Cieslewicz designed a method to find a specific amino-acid sequence - or a peptide - that binds only the harmful macrophages in tumors and ignores helpful ones in the bodies of mice. When this sequence was injected into mice with cancer, the research team found that the peptide collected in the macrophage cells within tumors, leaving alone other healthy organs.

"Once they discovered they could deliver the peptide sequence to specific cells, the researchers attached another peptide to successfully kill the harmful macrophages without affecting other cells. The mice had slower tumor growth and better survival when treated with this material.

The research team plans to test this method with existing cancer drugs to hopefully boost the success of other treatments.

"The peptide sequence that successfully bound to harmful macrophages in mice doesn't bind to their counterparts in humans, Pun said, but the researchers expect soon to find a similar peptide that targets human cells. They plan to use this method to investigate treatments for other types of cancer, including breast and pancreatic cancers."

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More information regarding the study can be found via the  Proceedings of the National Academy of Sciences.