A Raman Spectroscopic Study of Cell Response to Clinical Doses of Ionizing Radiation

Abstract

The drive toward personalized radiation therapy (RT) has created significant interest in determining patient-specific tumor and normal tissue responses to radiation. Raman spectroscopy (RS) is a non-invasive and label-free technique that can detect radiation response through assessment of radiation-induced biochemical changes in tumor cells. In the current study, single-cell RS identified specific radiation-induced responses in four human epithelial tumor cell lines: lung (H460), breast (MCF-7, MDA-MB-231), and prostate (LNCaP), following exposure to clinical doses of radiation (2-10 Gy). At low radiation doses (2 Gy), H460 and MCF-7 cell lines showed an increase in glycogen-related spectral features, and the LNCaP cell line showed a membrane phospholipid-related radiation response. In these cell lines, only spectral information from populations receiving 10 Gy or less was required to identify radiation-related features using principal component analysis (PCA). In contrast, the MDA-MB-231 cell line showed a significant increase in protein relative to nucleic acid and lipid spectral features at doses of 6 Gy or higher, and high-dose information (30, 50 Gy) was required for PCA to identify this biological response. The biochemical nature of the radiation-related changes occurring in cells exposed to clinical doses was found to segregate by status of p53 and radiation sensitivity. Furthermore, the utility of RS to identify a biological response in human tumor cells exposed to therapeutic doses of radiation was found to be governed by the extent of the biochemical changes induced by a radiation response and is therefore cell line specific. The results of this study demonstrate the utility and effectiveness of single-cell RS to identify and measure biological responses in tumor cells exposed to standard radiotherapy doses.

Raman profile alterations of irradiated human nasopharyngeal cancer cells detected with laser tweezer Raman spectroscopy

“…We found that the difference in proteins was prominent, compared to other cellular components between the control and irradiated group at the cell level, suggesting that the radiation effect was concentrated in the majority of some amino acids molecules or deformation mode. 9 For amino acids in CNE2 cells ( Fig. 4(a)), the relative contents of protein bands such as tryptophan (the peaks at 875, 1552 and 1612 cm À1 ) and tyrosine (the peaks at 492 and 1612 cm À1 ) were signicantly different between the control and irradiated group (p < 0.05).…”

“…6,7 The radioresistant lung and breast cells showed radiation-induced RS spectral features as glycogen accumulation at low RT doses, whereas the radiosensitive prostate cells showed some membrane phospholipid-related alterations. 8,9 Roman et al analyzed cytoplasmic and nuclear regions of irradiated prostate cancer cells (PC-3) and suggested various DNA damages located in those two regions. 10 Lasalvia et al observed that DNA was damaged in breast cells (MCF10A) irradiated by protons, in particular the O-P-O stretching mode at about 784 cm À1 .…”

Multi-centre Raman spectral mapping of oesophageal cancer tissues: a study to assess system transferability

“…RS has the potential to be more automated and adaptable to routine screening and provides a spectroscopic signature of all molecular constituents of the tissue sample, which facilitates the analysis and use of subtle molecular changes to classify different pathology and tissue states. Due to these pathology and tissue-specific spectroscopic signatures, RS has been used as a tool in histopathology [8][9][10][11][12][13][14] , and cytology [15][16][17][18] . It is based on inelastic light scattering and occurs when the biological sample is illuminated by monochromatic laser light.…”

Raman Spectroscopy of Human Lens Epithelial Cells Exposed to a Low-Dose Range of Ionizing Radiation

“…RS has been used to detect changes in cells and tissues exposed to ionizing radiation. [15][16][17][18][19][20][21][22][23][24][25] Past studies on pure samples of concentrated DNA have shown radiation induced changes to DNA, 26,27 believed to be due to structural changes. Similar studies have shown detectable changes in proteins, and lipids.…”

“…17,18 Similar studies in a lower, clinically relevant dose range from 2-10 Gy have also been performed. 21 One biomolecular change some of these studies detected was an increase of glycogen within radioresistant human lung cancer cells in vitro, 22 as well as in vivo using tumour xenographs of the same cells. 24 While these studies show great potential for using RS to detect biochemical changes in irradiated cells, they do not involve using RS for purposes of radiation dosimetry.…”