Fourier Transform Infrared Polarization Contrast Imaging Recognizes Proteins Degradation in Lungs upon Metastasis from Breast Cancer

Abstract

The current understanding of mechanisms underlying the formation of metastatic tumors has required multi-parametric methods. The tissue micro-environment in secondary organs is not easily evaluated due to complex interpretation with existing tools. Here, we demonstrate the detection of structural modifications in proteins using emerging Fourier Transform Infrared (FTIR) imaging combined with light polarization. We investigated lungs affected by breast cancer metastasis in the orthotopic murine model from the pre-metastatic phase, through early micro-metastasis, up to an advanced phase, in which solid tumors are developed in lung parenchyma. The two IR-light polarization techniques revealed, for the first time, the orientational ordering of proteins upon the progression of pulmonary metastasis of breast cancer. Their distribution was complemented by detailed histological examination. Polarized contrast imaging recognised tissue structures of lungs and showed deformations in protein scaffolds induced by inflammatory infiltration, fibrosis, and tumor growth. This effect was recognised by not only changes in absorbance of the spectral bands but also by the band shifts and the appearance of new signals. Therefore, we proposed this approach as a useful tool for evaluation of progressive and irreversible molecular changes that occur sequentially in the metastatic process.

High-Resolution Fourier Transform Infrared (FT-IR) Spectroscopic Imaging for Detection of Lung Structures and Cancer-Related Abnormalities in a Murine Model

“…2f). 10,39 The light green class also showed the highest level of proteins with a-helical conformations (1653 cm -1 ) and the lowest contribution of triple helix among all classes of the UHCA map. The purple and dark blue clusters were discriminated by UHCA analysis based on the intense FT-IR bands at 1683, 1634, and 1312 cm -1 assigned to proteins (Table S1, Fig.…”

“…9 A detailed description of collagens in lungs has been reported in our previous work. 10 The bronchioles are the narrowest canals of the airways (0.5-1 mm in diameter) that eventually lead to the alveoli. In these structures, gas (oxygen and carbon dioxide) exchange takes place.…”

“…We already showed in a few reports that this molecular imaging technique is capable to identify metastatic cancer cells as well as the chemical changes associated with the metastatic process in the lung parenchyma. 10,[24][25][26][27][28] Since the size of mentioned above lung structures varies from 5 mm up to 600 mm, the high spatial resolution of FT-IR imaging is required to observe the minute components and to determine their spectroscopic patterns. For this purpose, we employed here high definition (HD) and ultrahigh (UHD) definition FT-IR imaging combined with a FPA detector incorporated by Agilent Technologies.…”

A glitch in the matrix: organ-specific matrisomes in metastatic niches

“…Proteomic analysis using Raman spectroscopy has allowed for investigation of subtle changes in multiple proteins simultaneously without requiring protein labeling [41]. Label-free analysis of lung PMNs was also accomplished using Fourier transform infrared imaging in conjunction with polarization contrast [72]. Advancements in MS-based proteomic analysis based on protein solubility have been used to analyze direct interactions of ECMassociated factors with the matrix in the lungs of mice at different states following bleomycininduced injury [73].…”

“…immense clinical impact where current understanding of ECM changes that support PMNs is lacking. Access to human tissue samples and the limited number of mouse models have hindered the progress in studying these sites, but recent innovations in in vitro ECM acquisition [77][78][79][80], analysis [42,72,76], and in vivo modeling may help [86,87]. Technical innovations have also presented novel therapeutic strategies that are 'outside the box' but may hold potential.…”