Caracterização bioquímica de células sadias e neoplásicas através de espectroscopia vibracional

The molecular mechanisms and changes leading to the development and progression of cancers are extremely complex. FTIR spectroscopy can detect biochemical features of biological materials, enabling the important characterization and differentiation of cells. By looking at the individual absorption bands, it is possible to spot similarities and differences between the cells, which help to understand the changes observed in the same disease cell line group or between healthy and diseases cells. In this work we characterized four sets of neoplastic cells with FTIR spectroscopy. Each cell set was composed of two cell lines: the first one was a set composed by murine melanoma (B16F10) and human melanoma (C8161), the second one was colorectal adenocarcinoma (HT-29), and adenocarcinoma of the cervix (HeLa), the third one two human breast cancers cell lines (SKBr3 cells and MCF-7), and the last one was human leukemia cell line (JURKAT) and peripheral blood mononuclear cell (PBMC). All cell lines were purchased from American Type Culture Collection (ATCC, Manassas, VA, USA). The biochemical analysis was conducted through Fourier transform infrared spectroscopy (Nicolet 380). The spectra were acquired with 2cm−1 resolution, 32 scans and spectral range between 4000 − 900cm−1. Comparing all cell lines, differences in the following absorption bands were identified: 1084cm−1 (DNA sugar and PO2), 1236cm −1 (phosphodiester bonds), 1540cm−1 (amide II stretching), 2851cm−1, and 2921cm−1 (CH2 stretching). Some groups revealed differences in the absorption bands related to C −C and C −O stretching (967cm−1), amide I beta sheet and alpha helix structure (1650cm−1 and 1742cm−1, respectively), allowing the characterization of these diseases, differentiating them efficiently through the area and peaks displacement of the absorption bands. Through this work it was possible to verify the FTIR spectroscopy potential for application on basic studies, aiming cells characterization from the biochemical point of view, trying to understand which biological factors are related to each spectral differences observed, and provide qualitative information concerning the chemical bonds associated with certain biomarkers in each biological sample. The study of the variation in the amount of certain macromolecules present in cells it was possible to analyse the absorption band areas for each identified band. Hypothesis were established based on assumptions with regard to differences related with molecules as DNA, RNA, proteins and lipids. The hypothesis were associated with biochemical characteristics of certain diseases groups such as genes and proteins hyper expression, which were related to the increase in area of the absorption bands related to each particular macromolecule. The ratio analysis between the areas of different absorption bands was another point discussed. By this analysis it was possible to define biomarkers key bands in cell differentiation. The ratios commonly used in the literature were compared and new combinations were evaluated, aiming more efficient differentiation. The new ratios defined were (i) 1053cm−1 and 1084cm−1; (ii) 1540cm−1 and