Chemotherapy may induce changes in healthy cells that protect nearby tumors from the effects of such treatment, according to a study published in Nature Medicine Sunday.
This discovery came as a surprise to the researchers who were probing the molecular basis of the development of treatment resistance in tumors subjected to chemotherapy. The inevitable development of tumor resistance to chemotherapy is a key problem for patients with solid tumors that have spread. Efforts to protect patients and their healthy tissues from the toxic effects of chemotherapy by delivering chemotherapy in lower doses or in cycles with breaks for cell recovery may inadvertently promote the emergence of tumor resistance.
To better understand this phenomenon, the team examined tissue collected from men with prostate cancer before and after treatment. They found that DNA damage in healthy neighboring fibroblast cells caused these healthy cells to secrete proteins that promote tumor growth.
In particular, the researchers found a 30-fold increase in the production of the protein WNT 16B. Subsequent experiments demonstrated the protein’s growth-promoting effect on cancer cells. This protein previously had been linked to normal development and in the growth of some cancers, but this is the first time it has been linked to the development of treatment resistance, according to a statement from the authors.
The findings emphasize the importance of the tumor’s environment, according to a statement from senior author Peter S. Nelson, MD, of the Fred Hutchinson Cancer Research Center’s Human Biology Division: “Cancer cells inside the body live in a very complex environment or neighborhood. Where the tumor cell resides and who its neighbors are influence its response and resistance to therapy.”
Targeting the production of WNT 16B in the tumor environment may help curb the development of resistance, but further study is necessary to assess the safety and efficacy of such an approach, the authors conclude.