title: Label-Free Raman Imaging to Monitor Breast Tumor Signatures.
abstract: Although not yet ready for clinical application, methods based on Raman spectroscopy have shown significant potential in identifying, characterizing, and discriminating between noncancerous and cancerous specimens. Real-time and accurate medical diagnosis achievable through this vibrational optical method largely benefits from improvements in current technological and software capabilities. Not only is the acquisition of spectral information now possible in milliseconds and analysis of hundreds of thousands of data points achieved in minutes, but Raman spectroscopy also allows simultaneous detection and monitoring of several biological components. Besides demonstrating a significant Raman signature distinction between nontumorigenic (MCF-10A) and tumorigenic (MCF-7) breast epithelial cells, our study demonstrates that Raman can be used as a label-free method to evaluate epidermal growth factor activity in tumor cells. Comparative Raman profiles and images of specimens in the presence or absence of epidermal growth factor show important differences in regions attributed to lipid, protein, and nucleic acid vibrations. The occurrence, which is dependent on the presence of epidermal growth factor, of new Raman features associated with the appearance of phosphothreonine and phosphoserine residues reflects a signal transduction from the membrane to the nucleus, with concomitant modification of DNA/RNA structural characteristics. Parallel Western blotting analysis reveals an epidermal growth factor induction of phosphorylated Akt protein, corroborating the Raman results. The analysis presented in this work is an important step toward Raman-based evaluation of biological activity of epidermal growth factor receptors on the surfaces of breast cancer cells. With the ultimate future goal of clinically implementing Raman-guided techniques for the diagnosis of breast tumors (e.g., with regard to specific receptor activity), the current results just lay the foundation for further label-free optical tools to diagnose the disease.
authors.affiliation: 1 Department of Physics, University of Texas at El Paso, El Paso, TX, USA.|2 Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX, USA.
authors.forename: Felicia S
authors.initials: FS
authors.lastname: Manciu
authors.affiliation: 1 Department of Physics, University of Texas at El Paso, El Paso, TX, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Ciubuc
authors.affiliation: 3 Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA.
authors.forename: Karla
authors.initials: K
authors.lastname: Parra
authors.affiliation: 1 Department of Physics, University of Texas at El Paso, El Paso, TX, USA.
authors.forename: Marian
authors.initials: M
authors.lastname: Manciu
authors.affiliation: 4 Division of Engineering, Mayo Clinic, Rochester, MN, USA.
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Bennet
authors.affiliation: 3 Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA.
authors.forename: Paloma
authors.initials: P
authors.lastname: Valenzuela
authors.affiliation: 1 Department of Physics, University of Texas at El Paso, El Paso, TX, USA.
authors.forename: Emma M
authors.initials: EM
authors.lastname: Sundin
authors.affiliation: 1 Department of Physics, University of Texas at El Paso, El Paso, TX, USA.
authors.forename: William G
authors.initials: WG
authors.lastname: Durrer
authors.affiliation: 1 Department of Physics, University of Texas at El Paso, El Paso, TX, USA.
authors.forename: Luis
authors.initials: L
authors.lastname: Reza
authors.affiliation: 2 Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX, USA.|3 Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA.
authors.forename: Giulio
authors.initials: G
authors.lastname: Francia
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D006801:Humans; D061986:MCF-7 Cells; D018613:Microscopy, Confocal; D013059:Spectrum Analysis, Raman; D013194:Staining and Labeling
chemical_list: D014408:Biomarkers, Tumor; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: DNA denaturation; EGF overexpression; MCF-7 cells; RNA; Raman spectroscopy