Determination of cellular differences of CD133+/CD44+ prostate cancer stem cells in two-dimensional and three-dimensional media by Fourier transformation infrared spectroscopy

INTRODUCTION: Spheroid cultures reflect properties of tumor tissue better than monolayer cultures in terms of internal dynamics and interaction with other cells. The aim of this study is to investigate the similarities and differences in CD133+/CD44+ prostate cancer stem cells (CSCs) produced in three-dimensional (3D) and two-dimensional (2D) culture media. METHODS: CSCs with CD133+/CD44+ surface marker properties in the DU-145 prostate cancer cell lines were isolated using flow cytometry (FACS). Spheroid structures were formed with agar-coated culture vessels. CSCs in 2D and 3D cultures were compared with Fourier transform infrared (FTIR) spectroscopy. RESULTS: CD133+/CD44+ cells were observed to form micro-aggregates in cultured media in the first week. In the second week, mature spheroid structures were formed. FTIR analysis revealed that the 2D and 3D (multicellular tumor spheroids) models of CSCs exhibit significant differences in proteins, lipids and nucleic acids. Significant differences were detected in membrane lipid acyl chain length, membrane thickness, protein secondary structures and DNA oligonucleotides. The results showed that spheroids in 3D culture medium exhibit similar properties to in vivo tumor tissue. DISCUSSION AND CONCLUSION: Physical, chemical and biological properties generated by environmental conditions significantly affect internal dynamics of cells and their interactions within the microenvironment. Reducing the cells in one dimension through the 2D culture medium does not reflect actual properties of cells. Therefore, cell dynamics in 3D culture media should be investigated. This study demonstrates that cellular lipids, membrane structure, protein secondary structures and nucleic acids of CSCs constituting an important cell population in cancer may be therapeutic targets