Study: Immune Cell That Drives Breast Cancer Could Be Effective Target in Novel Immunotherapies

New research findings published in Cell Reports identified a type of immune cells that acts as a major driver of breast cancer growth by preventing the accumulation of a specific protein that induces anti-tumor responses, according to a press release.

"A deeper understanding of the immunobiology of breast cancer is critical to the success in harnessing immunotherapeutic approaches to improve breast cancer survival," said Paula Bos, PhD, member of the Cancer Biology research program at VCU Massey Cancer Center and assistant professor in the Department of Pathology at the VCU School of Medicine, in a press release.

In previous studies, the research team demonstrated that targeting regulatory T cells (Treg) in breast cancer models significantly reduced tumor growth and metastasis, but it remained unclear on a molecular level why this tumor reduction was happening.

Treg cells are a special class of immune cells that possess a unique ability to suppress the function of other immune cells, and this function serves to protect the organism from overreacting to certain molecules created within the body. However, in many cases, it subdues the immune system’s ability to attack cancer cells. This makes Treg cells abundant in solid tumors, particularly breast cancers, and are commonly associated with worse outcomes, according to the study.

The specific protein, interferon gamma (IFN-γ), has powerful anti-tumor properties and includes the activation of macrophages, which are cells that can initiate inflammation and prevent cancer growth.

The latest study from Bos and her team suggests that Treg cells suppress IFN-γ production by CD4 T lymphocytes, a type of white blood cell, further instigating disease progression. After analyzing breast cancer models in which Treg cells had been targeted and destroyed, Bos discovered an increased presence of IFN-γ and functional reprogramming of macrophages into tumor-fighting cells, according to the press release.

"Additionally, we demonstrated better overall survival in human cancers with similar genetic patterns to those observed in mice with breast cancer whose Treg cells were eliminated," Bos said in the press release.

This research is the first of its kind to study the mechanistic function of Treg cells in breast cancer, and Bos said these findings validate the potential for adoptive transfer therapeutics using macrophages programmed with the IFN-γ protein to effectively treat breast cancer.

"Our work raises the possibility that white blood cells can be extracted from cancer patients, reprogrammed outside of their body through brief exposure to the IFN-γ protein and re-infused back into the patient, contributing to the generation of anti-tumor responses," Bos said in the press release.

REFERENCE

Immune cell that drives breast cancer could be effective target in novel immunotherapies. EurekAlert! Published December 15, 2020. Accessed April 21, 2021. https://www.eurekalert.org/pub_releases/2020-12/vcu-ict121520.php