Cellular and spectroscopic characterization of cancer stem cell-like cells derived from A549 lung carcinoma

• Published in: Journal of cancer research and therapeutics Vol. 12; no. 3; pp. 1144 - 1152
• Main Authors: Balla, Murali, Ningthoujam, Raghumani, Kumar, Mukesh, Bandekar, Jayant, Pandey, Badri
• Format: Journal Article
• Language: English
• Published: India Wolters Kluwer India Pvt. Ltd 01-07-2016; Medknow Publications and Media Pvt. Ltd; Medknow Publications & Media Pvt. Ltd
• Subjects: Adenocarcinoma - chemistry; Adenocarcinoma - metabolism; Adenocarcinoma of Lung; Biomarkers; Cancer; Care and treatment; Cell Line, Tumor; Cell Survival - radiation effects; Circular Dichroism; Cloning; Fourier transforms; Free radicals; Genetic aspects; Humans; Lipids; Lung cancer; Lung Neoplasms - chemistry; Lung Neoplasms - metabolism; Medical prognosis; Metastasis; Microscopy; Neoplastic Stem Cells - chemistry; Neoplastic Stem Cells - metabolism; Neoplastic Stem Cells - radiation effects; Oxidation-Reduction; Prognosis; Proteins; Radiation Tolerance; Single-Cell Analysis; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis - methods; Stem cells; Studies; Superoxide Dismutase - metabolism; United States > US; lung cancer; single cell assay; Cancer stem cells; spectroscopy; radiosensitivity
• ISSN: 0973-1482; 1998-4138
• DOI: 10.4103/0973-1482.171365

Background: Cancer stem cells (CSCs) are increasingly being realized to play a significant role in the mechanism of chemo-, radio-resistance, and metastasis of cancer. However, studies for spectral markers of CSCs using Fourier transform infrared (FT-IR) and circular dichroism (CD) spectroscopy are limited in the literature.
Materials and Methods: In the present study, CSCs obtained from single cell assay of human lung adenocarcinoma (A549) cells were characterized using CD44+/CD24−/low phenotype expression, Hoechst 33342 dye efflux assay, and expression of stemness genes. Spectral changes in cancer cells and clones enriched with CSCs were studied by FT-IR and CD spectroscopy.
Results: The changes in FT-IR spectra of clones enriched with CSCs showed the difference in the secondary protein structure as compared to nonstem cancer cells. Moreover, A549 clone cells showed higher C-O band of carbohydrates and deoxyribose ring vibrations of Z-form of DNA. These results were further corroborated with CD spectroscopy that showed increased alpha helix proteins and difference in DNA conformation in clones enriched with CSCs. FT-IR studies also showed higher imidazole-metal interactions in clones enriched with CSCs. These results are in agreement with higher activity of one of the metalloproteins that is, superoxide dismutase in clones enriched with CSCs and their increased radioresistance.
Conclusions and General Significance: Overall, these observations provide novel FT-IR and CD spectroscopy signatures in A549 clones enriched with CSCs, which may have implications in the quantifying magnitude of CSCs as prognostic markers in cancer therapy.