Establishment of Doxorubicin Resistant Stem-like Cell line from MCF-7 Cells

Abstract

Background Conventional therapy of Breast cancer (BCa) is associated with numerous challenges, relapse being the topmost. It has been shown that disease relapse occurs due to the existence of cancer stem cells (CSCs), residing within the tumor. Objectives To develop a cancer stem cell line model, exploiting the property of stem cells to resist treatment with anti-cancer therapeutic agents and to develop novel therapeutic interventions targeting the elimination of CSCs. Methods Single-cell clones (SCC) from MCF-7 cells were established in 96-well plates using a culture medium containing 5% FBS. Enrichment of cancer stem cells was carried out from established single cell clones which were initially cultured in a serum-deprived nutrient medium for six weeks followed by Doxorubicin treatment. Doxorubicin-resistant clones were established and evaluated for their growth and sphere-forming abilities. Further, these clones were characterized based on the presence of stem-cell markers using a semi-quantitative reverse transcription-polymerase chain reaction and results were compared with the parental MCF-7 cell line. Results In a complete medium, these spheres differentiated and started growing as a monolayer with differential expression levels of genes involved in stemness and cellular differentiation. When these spheres were sub-cultured again in stem-cell medium and detached to give rise to single cells, these clones retained sphere-forming ability. Doxorubicin-resistant clones showed a tendency to grow in spheres in a stem-cell medium with serum-deprived culture conditions. Conclusion Our results provide undeviating evidence of the successful establishment of clones of MCF-7 cell line exhibiting stem cell-like properties. These cell lines have been reprogrammed as stem cell-like models and can be used to delineate recurrent breast cancer attributed to CSCs.