Differentiation therapy: targeting breast cancer stem cells to reduce resistance to radiotherapy and chemotherapy

Excerpt

Studies have shown that cancer stem-like cells (CSCs) from solid cancers are resistant to both radiotherapy and chemotherapy. We have shown that primary breast cancers (n = 8) and a breast cancer cell line (MCF7) enriched for breast cancer stem cells (BCSC) using mammosphere (MS) clonogenic culture can preferentially survive radiotherapy and chemotherapy treatment in vitro, showing ≥ 50% increase in MS survival compared with non-BCSC enriched cells. The BCSC enriched population, defined by the cell surface markers ESA⁺/CD44⁺/CD24^-/low, had reduced levels of DNA damage (measured by γH2AX) after 4 Gy irradiation or doxorubicin (1 μM) treatment. This suggests that the BCSC enriched population avoids or repairs the DNA damage significantly more than the whole population. …