Abstract

In this work we have used Fourier transform infrared (FTIR) / vibrational absorption (VA) spectroscopy to study two cancer cell lines: the Henrietta Lacks (HeLa) human cervix carcinoma and 5637 human bladder carcinoma cell lines. Our goal is to experimentally investigate biochemical changes and differences in these cells lines utilizing FTIR spectroscopy. We have used the chemometrical and statistical method principal component analysis (PCA) to investigate the spectral differences. We have been able to identify certain bands in the spectra which are so-called biomarkers for two types of cell lines, three groups for the 5637 human bladder carcinoma cell line (5637A, 5637B and 5637C), and another one for the HeLa human cervix carcinoma cell line. The vibrational modes can be assigned to specific bands involving characteristic motions of the protein backbone. This work shows that infrared vibrational absorption (VA) spectroscopy can be used as a useful tool in medical diagnostics that provides in principle additional information and detail to that which can be obtained/provided from conventional histological studies, and more conventional mass spectroscopic and NMR techniques. The use of high level vibrational spectroscopic simulation, in addition to the chemometric and statistical tools of PCA, linear and quadratic discriminant analysis, and artificial networks methods that are good at finding correlations, but provide little if any physical, chemical and biochemical insight into the nature of the changes at a molecular level, is also strongly advocated and helpful to gain more physical, chemical and biological insight. Hence the combination of vibrational spectroscopic simulations and experimental vibrational absorption spectroscopy and imaging are advocated for future developments in this field.

Keywords: Principal component analysis (PCA), Quadratic discriminant analysis (QDA), Linear discriminant analysis (LDA), Fourier transform infrared (FTIR), Vibrational absorption (VA), Cervical cancer, Bladder cancer, Henrietta Lacks (HeLa) cancer cell line