Expansion and characterization of breast cancer stem cells for the development of BCSCtargeting therapeutic strategies

Breast tumors contain a small population of tumor initiating stem-like cells, termed breast cancer stem cells (BCSCs) which have been linked to tumor relapse, metastasis, and resistance to radio- and chemotherapy. They are distinguished by characteristic markers, such as the cell surface antigens CD44high/CD24low and ALDH1 enzymatic activity. Since the scarce number of BCSCs severely hampers their isolation and purification for further research, it is necessary to expand and enrich them in vitro. In the present study, we expanded BCSCs as tumorsphere cells from the human breast cancer cell line MCF-7 and characterized them in comparison to MCF-7 adhesive cells. Materials and methods: Single cell suspensions derived from human breast cancer cell line (MCF-7) were seeded in ultra low attachment plates in serum free specific media. The Aldefluorassay and immunophenotyping was carried out for ALDH1 functional marker and surface antigens expression (CD44high/CD24low).Results: we found that BCSCs can expand in serum-free medium as non-adherent spheres of ells. Resulting primary tumorsphere after a week (termed T1 tumorspheres) were subjected to passaging every 7th day leading to the generation of T2, T3, and T4 tumorspheres. Flowcytometry data analysis by means of FlowJo software demonstrated that tumorspheres have higher percentage of CD44high/CD24low and ALDH-expressing cells. Discussion: The study suggest that BCSCs have a higher proportion in suspension culture as tumorsphere and this technique can enrich and expand breast cancer stem cells as undifferentiated cells in vitro for further studding the cells behavior. Furthermore, this population would be a suitable in vitro model to develop a new treatment strategy that can effectively eliminate the BCSCs that drive tumor growth and recurrence.

کلیدواژه ها:

Breast cancer ، tumorspheres ، cancer stem cells ، MCF-7