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Updated: Oct 6, 2025
Isolation and Functional Assessment of Human Breast Cancer Stem Cells from Cell and Tissue Samples
Published on: October 2, 2020
O-Acetyl-GD2 as a Therapeutic Target for Breast Cancer Stem Cells
Jing-Yan Cheng1, Jung-Tung Hung1, Juway Lin1
1Institute of Stem Cell and Translational Cancer Research, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.
Synopsis:
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.
Background:
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.
Method:
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 in vitro and tumor growth in vivo using PDX models.
Result:
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 in vitro and tumor initiation in vivo than OAcGD2- cells. In addition, the majority of OAcGD2+ cells were aldehyde dehydrogenase (ALDH+) or CD44hiCD24lo, 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 in vivo tumorigenicity. In vitro, 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 in vivo dramatically suppressed tumor growth of OAcGD2+ breast CSCs (BCSCs) with complete tumor abrogation in 3/6 mice.
Conclusion:
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.
Insights
A novel sugar-lipid molecule, OAcGD2, marks breast cancer stem cells. Targeting these cells with anti-OAcGD2 mAb8B6 antibody shows potential for superior cancer treatment by reducing recurrence and metastasis.
Area of Science:
- Oncology
- Immunotherapy
- Molecular Biology
Background:
- Cancer stem cells (CSCs) drive tumor progression and recurrence.
- CSCs are resistant to conventional therapies, necessitating their eradication for durable responses.
- GD2 is a known CSC marker in triple-negative breast cancer; anti-GD2 immunotherapy has shown promise.
Purpose of the Study:
- To determine if OAcGD2 is a novel marker for breast cancer stem cells (BCSCs).
- To investigate the efficacy of anti-OAcGD2 antibody mAb8B6 in targeting and eradicating BCSCs.
- To assess the therapeutic potential of mAb8B6 in preclinical breast cancer models.
Main Methods:
- OAcGD2 expression was analyzed in patient-derived xenografts (PDXs) using flow cytometry with mAb8B6.
- Stemness properties of OAcGD2+ cells were evaluated via in vitro mammosphere formation and in vivo tumor initiation assays.
- The anti-tumor effects of mAb8B6 were assessed in PDX models, comparing its efficacy to doxorubicin.
Main Results:
- OAcGD2 expression strongly correlated with known CSC markers across various breast cancer subtypes in PDXs.
- Sorted OAcGD2+ cells exhibited enhanced in vitro and in vivo tumor-forming capabilities.
- mAb8B6 treatment suppressed tumor growth, reduced CSC populations, and induced apoptosis of OAcGD2+ cells, outperforming doxorubicin in some models.
Conclusions:
- OAcGD2 is identified as a novel and reliable marker for BCSCs across diverse breast cancer subtypes.
- Anti-OAcGD2 mAb8B6 demonstrates direct eradication of OAcGD2+ BCSCs and significant tumor growth suppression in vivo.
- mAb8B6 represents a promising immunotherapeutic strategy for targeting and eliminating BCSCs to improve treatment outcomes.
