SITC 2021: Anti-CD47 Immunotherapy Under Study for Reducing Breast Cancer Brain Metastasis
Posted: Friday, December 3, 2021
During the 2021 Society for Immunotherapy of Cancer (SITC) Annual Meeting, Jessica Mackert, PhD, of Wake Forest University, Winston-Salem, North Carolina, and colleagues presented their study findings on the evaluation of the use of anti-CD47 immunotherapy to prevent brain metastasis in patients with breast cancer (Abstract 270). The study authors concluded that CD47 blockade may prove to be an effective treatment, as it reduced metastatic brain lesions and tumor burden, reduced extracellular matrix-associated gene expression, and improved overall survival in mice.
Biopsies from patients with breast cancer were stained with anti-CD47 antibodies, and CD47 null mice were used for the brain metastasis model by intracardiac injection of E0071-Br-Luc cells. Analysis involved quantification of brain metastatic burden, immunohistochemical analysis to evaluate tumor-infiltrating macrophages, and RNA sequencing for gene-expression analysis.
An 89% increase in CD47 expression was observed in metastatic tumors compared with primary lesions via immunohistochemistry (P ≤ .05). In mice harboring brain metastatic T1br3 orthotopic tumors, anti-CD47 treatment reduced tumor weight and volume by more than 50% compared with control mice (P ≤ .05); F4/80 macrophage markers increased fivefold in tumors (P ≤ .05).
A 60% increase in survival and an 89% decrease in metastatic brain lesions were reported in CD47 null mice compared with control mice in the brain metastasis model. Notably, 318 uniquely expressed genes were revealed by RNA sequencing in tumors treated with an anti-CD47 antibody, and there was a significant decrease in extracellular matrix organization–related genes.
Disclosure: No disclosure information was provided.