After surgery to remove tumors, some cancer cells can be left behind where they can grow back or spread to a new part of the body. Researchers at the University of Wisconsin-Madison have now developed a hydrogel that can be applied post-surgery to prevent or slow tumor regrowth.
The gel works by releasing two compounds selected to strategically keep cancer from coming back after surgery. First is a drug called Pexidartinib, which is already in use to inhibit tumor-associated macrophages (TAMs). These are immune cells that have, for unclear reasons, “switched sides” and now contribute to creating a pro-cancer environment. As such, inhibiting these TAMs slows the growth (or regrowth) of cancer.
The second component is made up of PD-1 antibodies, which help train T cells to recognize and attack cancer cells. These are bound to platelets for stability. Together, the two components prevent the formation of a microenvironment that’s favorable to cancer growth, and help the immune system clear out any cancer cells remaining after surgery. After its work is done, the gel is designed to biodegrade safely in the body.
The researchers tested the gel in mouse models of several different types of cancers, including colon cancer, melanoma, sarcoma, and triple negative breast cancer. The gel significantly reduced recurrence and metastasis of the cancer, and extended the survival rates of the mice – all control animals succumbed within 36 days, while survival rates ranged between 50 and 66 percent for treated mice, depending on the type of cancer.
The local application of the gel also helps prevent side effects that can arise if a drug is delivered system-wide. As such, no major side effects were seen in the test mice.
Importantly, the team says that some of these cancers don’t usually respond well to immune therapy, and are prone to metastasizing, so the effectiveness of the gel treatment is encouraging.
“We are really glad to see that this local strategy can work against so many different kinds of tumors, especially these non-immunogenic tumors,” said Quanyin Hu, lead researcher on the study. “We are even more glad to see this local treatment can inhibit tumor metastasis.”
The researchers plan to continue further animal tests, with a goal of eventually preparing the gel for human trials.
The research was published in the journal Nature Communications.
Source: University of Wisconsin-Madison