O-Acetyl-GD2 as a Therapeutic Target for Breast Cancer Stem Cells

• Published in: Frontiers in immunology 2022-01, Vol.12, p.791551-791551
• Main Authors: Cheng, Jing-Yan, Hung, Jung-Tung, Lin, Juway, Lo, Fei-Yun, Huang, Jing-Rong, Chiou, Shih-Pin, Wang, Ya-Hui, Lin, Ruey-Jen, Wu, Jen-Chine, Yu, John, Yu, Alice L
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Monoclonal - pharmacology; antibody; Apoptosis - drug effects; Biomarkers; breast cancer stem cells markers; Breast Neoplasms - pathology; Cell Proliferation - drug effects; Female; Gangliosides - metabolism; glycosphingolipid (GSL) glycans; Humans; Immunology; immunotherapy; Mice; Neoplastic Stem Cells - drug effects; Neoplastic Stem Cells - pathology; PDX (patient-derived xenografts); Xenograft Model Antitumor Assays
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2021.791551

A sugar-lipid molecule called OAcGD2 is a novel marker for breast cancer stem cells. Treatment with anti-OAcGD2 mAb8B6 may have superior anticancer efficacy by targeting cancer stem cells, thereby reducing metastasis and recurrence of cancer. Cancer stem cells (CSCs) that drive tumor progression and disease recurrence are rare subsets of tumor cells. CSCs are relatively resistant to conventional chemotherapy and radiotherapy. Eradication of CSCs is thus essential to achieve durable responses. GD2 was reported to be a CSC marker in human triple-negative breast cancer, and anti-GD2 immunotherapy showed reduced tumor growth in cell lines. Using a specific anti-OAcGD2 antibody, mAb8D6, we set out to determine whether OAcGD2 cells exhibit stem cell properties and mAb8D6 can inhibit tumor growth by targeting OAcGD2 CSCs. OAcGD2 expression in patient-derived xenografts (PDXs) of breast cancer was determined by flow cytometric analyses using mAb8D6. The stemness of OAcGD2 cells isolated by sorting and the effects of mAb8B6 were assessed by CSC growth and mammosphere formation and tumor growth using PDX models. We found that the OAcGD2 expression levels in six PDXs of various molecular subtypes of breast cancer highly correlated with their previously defined CSC markers in these PDXs. The sorted OAcGD2 cells displayed a greater capacity for mammosphere formation and tumor initiation than OAcGD2 cells. In addition, the majority of OAcGD2 cells were aldehyde dehydrogenase (ALDH ) or CD44 CD24 , the known CSC markers in breast cancer. Treatment of PDXs-bearing mice with mAb8B6, but not doxorubicin, suppressed the tumor growth, along with reduced CSCs as assessed by CSC markers and tumorigenicity. , mAb8B6 suppressed proliferation and mammosphere formation and induced apoptosis of OAcGD2 breast cancer cells harvested from PDXs, in a dose-dependent manner. Finally, administration of mAb8B6 dramatically suppressed tumor growth of OAcGD2 breast CSCs (BCSCs) with complete tumor abrogation in 3/6 mice. OAcGD2 is a novel marker for CSC in various subtypes of breast cancer. Anti-OAcGD2 mAb8B6 directly eradicated OAcGD2 cells and reduced tumor growth in PDX model. Our data demonstrate the potential of mAb8B6 as a promising immunotherapeutic agent to target BCSCs.