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Combining CD47 blockade with trastuzumab eliminates HER2-positive breast cancer cells and overcomes trastuzumab tolerance
- Source :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Year :
- 2021
- Publisher :
- Proceedings of the National Academy of Sciences, 2021.
-
Abstract
- Significance This study demonstrates the efficacy of combining macrophage-checkpoint inhibition with tumor-specific antibodies for cancer immunotherapy. The combination of anti-CD47 (magrolimab) and anti-HER2 (trastuzumab) antibodies eliminated HER2+ breast cancer cells with increased efficacy due to the enhancement of antibody-dependent cellular phagocytosis by macrophages, even when the cancer cells were tolerant to trastuzumab-induced antibody-dependent cellular cytotoxicity by natural killer cells. We believe these findings present a promising therapeutic approach for treating HER2+ breast cancer patients whose tumors are either sensitive or resistant to trastuzumab treatment, as long as the cells harbor the HER2 trastuzumab-binding epitope. This study supports the notion that combining CD47 blockade with existing macrophage FcR-engaging tumor-specific antibodies may be an effective approach for treating a wide range of cancers.<br />Trastuzumab, a targeted anti-human epidermal-growth-factor receptor-2 (HER2) monoclonal antibody, represents a mainstay in the treatment of HER2-positive (HER2+) breast cancer. Although trastuzumab treatment is highly efficacious for early-stage HER2+ breast cancer, the majority of advanced-stage HER2+ breast cancer patients who initially respond to trastuzumab acquire resistance to treatment and relapse, despite persistence of HER2 gene amplification/overexpression. Here, we sought to leverage HER2 overexpression to engage antibody-dependent cellular phagocytosis (ADCP) through a combination of trastuzumab and anti-CD47 macrophage checkpoint immunotherapy. We have previously shown that blockade of CD47, a surface protein expressed by many malignancies (including HER2+ breast cancer), is an effective anticancer therapy. CD47 functions as a “don’t eat me” signal through its interaction with signal regulatory protein-α (SIRPα) on macrophages to inhibit phagocytosis. Hu5F9-G4 (magrolimab), a humanized monoclonal antibody against CD47, blocks CD47’s “don’t eat me” signal, thereby facilitating macrophage-mediated phagocytosis. Preclinical studies have shown that combining Hu5F9-G4 with tumor-targeting antibodies, such as rituximab, further enhances Hu5F9-G4’s anticancer effects via ADCP. Clinical trials have additionally demonstrated that Hu5F9-G4, in combination with rituximab, produced objective responses in patients whose diffuse large B cell lymphomas had developed resistance to rituximab and chemotherapy. These studies led us to hypothesize that combining Hu5F9-G4 with trastuzumab would produce an anticancer effect in antibody-dependent cellular cytotoxicity (ADCC)-tolerant HER2+ breast cancer. This combination significantly suppressed the growth of ADCC-tolerant HER2+ breast cancers via Fc-dependent ADCP. Our study demonstrates that combining trastuzumab and Hu5F9-G4 represents a potential new treatment option for HER2+ breast cancer patients, even for patients whose tumors have progressed after trastuzumab.
- Subjects :
- 0301 basic medicine
macrophage checkpoint immunotherapy
Medical Sciences
Receptor, ErbB-2
medicine.drug_class
medicine.medical_treatment
Breast Neoplasms
CD47 Antigen
Antibodies, Monoclonal, Humanized
Monoclonal antibody
Mice
03 medical and health sciences
breast cancer
Antineoplastic Agents, Immunological
0302 clinical medicine
Breast cancer
Trastuzumab
Cell Line, Tumor
medicine
Animals
Humans
CD47
skin and connective tissue diseases
neoplasms
antibody therapy
Antibody-dependent cell-mediated cytotoxicity
Chemotherapy
Multidisciplinary
business.industry
Macrophages
Antibody-Dependent Cell Cytotoxicity
Immunotherapy
Biological Sciences
medicine.disease
Mice, Inbred C57BL
030104 developmental biology
Drug Resistance, Neoplasm
030220 oncology & carcinogenesis
Cancer research
Drug Therapy, Combination
Female
Rituximab
business
medicine.drug
Subjects
Details
- ISSN :
- 10916490 and 00278424
- Volume :
- 118
- Database :
- OpenAIRE
- Journal :
- Proceedings of the National Academy of Sciences
- Accession number :
- edsair.doi.dedup.....3b86c70a3c209942c00774efc9102ada