GCI Discovery: a Driver of Breast Cancer Recurrence and a Promising Therapeutic Target

A recent study from the Muller Laboratory at the Rosalind and Morris Goodman Cancer Institute (GCI), published in Nature Communications, identified osteopontin as a driving force behind breast cancer recurrence. Breast cancer that re-appears after an initial treatment is often resistant to therapy and highly lethal. To address this challenge, PhD candidate Yu Gu led research showing that osteopontin levels were higher in initial tumors that later recurred--and even higher in the recurrent tumors themselves

Osteopontin is a protein traditionally involved in bone remodelling. When secreted by breast cancer cells, the researcher team showed that osteopontin remodels the surrounding environment to favour tumor growth. The researchers discovered that osteopontin can directly promote cancer cell growth, prevent tumor-killing immune cells from entering the tumor, and also recruit other immune cells that breast cancers can hijack to assist with tumor growth.

By determining the role of osteopontin in driving recurrence, the researchers identified new therapeutic opportunities. According to Ms. Gu, “one of the most exciting findings of our study is the potential of targeting osteopontin. In mouse models of recurrent breast cancer, inhibiting osteopontin effectively reduced primary tumor burden and lung metastasis.” The team also found that targeting osteopontin improved immunotherapy-resistant tumor responses to existing immune checkpoint inhibitors. These findings suggest that osteopontin could become a valuable therapeutic target for combating breast cancer recurrence and improving patient outcomes.

This highly collaborative project was supported by the Park and Tremblay laboratories at the GCI,  along with researchers from the Dana-Faber Cancer Institute and the University of Pennsylvania.