Original Article
Investigation of multicellular tumor spheroids enriched for a cancer stem cell phenotype
Abstract
Background: Cancer stem cells (CSCs) provide self-renewal of the tumor after radiation and chemotherapy. These cells are important during tumor development. The in vitro model of avascular tumor that enriched of cells with stem like characteristics is critical to understanding of the role CSCs in the tumor.
Methods: Cell viability was evaluated by MTT assay. The expression of cancer stem cells markers (CD133, CD44, CD24 and bmi-1) in 2D cell culture and multicellular tumor spheroids (MCTS) of MCF-7 cells was evaluated. The Stemi2000 software AxioVisionRed 4.7 was used for image processing. The volume of spheroids was calculated by Bjerkvig formula.
Results: The highest expression of CD133, CD44, CD24 and bmi-1 receptors was detected in MCTS, enriched with cancer stem cells (eMCTS). Cell aggregates of eMCTS culture were returned from suspension to adhesive conditions. It was found that the cells of the MCTS surface layers were enriched with CD133, CD44, CD24, bmi-1, EpCAM, vim markers, but not adherent cells. eMCTS are less sensitive to anticancer drugs (cisplatin, methotrexate and doxorubicin), than adhesive cell culture and MCTS cultured under standard conditions in a complete nutrient medium (P<0.05).
Conclusions: We observed that eMCTS population possesses aggressive phenotypic characteristics such as invasion, cancer stem cell markers and chemoresistance. eMCTS model could improve the screening efficiency of therapeutical agents against CSCs.
Methods: Cell viability was evaluated by MTT assay. The expression of cancer stem cells markers (CD133, CD44, CD24 and bmi-1) in 2D cell culture and multicellular tumor spheroids (MCTS) of MCF-7 cells was evaluated. The Stemi2000 software AxioVisionRed 4.7 was used for image processing. The volume of spheroids was calculated by Bjerkvig formula.
Results: The highest expression of CD133, CD44, CD24 and bmi-1 receptors was detected in MCTS, enriched with cancer stem cells (eMCTS). Cell aggregates of eMCTS culture were returned from suspension to adhesive conditions. It was found that the cells of the MCTS surface layers were enriched with CD133, CD44, CD24, bmi-1, EpCAM, vim markers, but not adherent cells. eMCTS are less sensitive to anticancer drugs (cisplatin, methotrexate and doxorubicin), than adhesive cell culture and MCTS cultured under standard conditions in a complete nutrient medium (P<0.05).
Conclusions: We observed that eMCTS population possesses aggressive phenotypic characteristics such as invasion, cancer stem cell markers and chemoresistance. eMCTS model could improve the screening efficiency of therapeutical agents against CSCs.
