Increased metabolic activity detected by flim in human breast cancer cells with desmoplastic reaction: a pilot study

Abstract

In breast cancer (BC), desmoplastic reaction, assembled primarily by fibroblasts, is associated with unfavorable prognosis, but the reason of this fact remains still unclear. In this context, nonlinear optics microscopy, including Fluorescence Lifetime Imaging Microscopy (FLIM), has provided advancement in cellular metabolism research. In this paper, our purpose is to differentiate BC cells metabolism with or without contact to desmoplastic reaction. Formalin fixed, paraffin embedded samples were used at different points of hematoxylin stained sections. Methodology: Sections from 14 patients with invasive ductal breast carcinoma were analyzed with FLIM methodology to NAD(P)H and FAD fluorescence lifetime on a Confocal Upright LSM780 NLO device (Carl Zeiss AG, Germany). Quantification of the fluorescence lifetime and fluorescence intensity was evaluated by SPC Image software (Becker & Hickl) and ImageJ (NIH), respectively. Optical redox ratio was calculated by dividing the FAD fluorescence intensity by NAD(P) H fluorescence intensity. Data value for FLIM measurements and fluorescence intensities were calculated using Wilcoxon test; p< 0.05 was considered significant. BC cells in contact with desmoplastic reaction presented a significantly lower NAD(P) H and FAD fluorescence lifetime. Furthermore, optical redox ratio was also lower in these tumor cells. Our results suggest that contact of BC cells with desmoplastic reaction increase their metabolic activity, which might explain the adverse prognosis of cases associated with higher peritumoral desmoplastic reaction