Optical Redox Imaging Detects the Effects of DEK Oncogene Knockdown on the Redox State of MDA-MB-231 Breast Cancer Cells
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Optical redox imaging (ORI), based on collecting the endogenous fluorescence of reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavoproteins (Fp) containing a redox cofactor flavin adenine dinucleotide (FAD), provides sensitive indicators of cellular metabolism and redox status. ORI indices (such as NADH, FAD, and their ratio) have been under investigation as potential progression/prognosis biomarkers for cancer. Higher FAD redox ratio (i.e., FAD/(FAD + NADH)) has been associated with higher invasive/metastatic potential in tumor xenografts and cultured cells. This study is to examine whether ORI indices can respond to the modulation of oncogene DEK activities that change cancer cell invasive/metastatic potential.
Using lentiviral shRNA, DEK gene expression was efficiently knocked down in MDA-MB-231 breast cancer cells (DEKsh). These DEKsh cells, along with scrambled shRNA-transduced control cells (NTsh), were imaged with a fluorescence microscope. In vitro invasive potential of the DEKsh cells and NTsh cells was also measured in parallel using the transwell assay.
FAD and FAD redox ratios in polyclonal cells with DEKsh were significantly lower than that in NTsh control cells. Consistently, the DEKsh cells demonstrated decreased invasive potential than their non-knockdown counterparts NTsh cells.
This study provides direct evidence that oncogene activities could mediate ORI-detected cellular redox state.
Key wordsOptical redox imaging FAD NADH Redox ratio DEK gene Knock down Breast cancer Invasive potential
The authors thank Ms. Jinxia Jiang for her assistance in part of the data acquisition and Dr. Zhenwu Lin for valuable discussion and support. The authors would also like to appreciate the valuable discussion with and support from Dr. Andrea Stout and Ms. Jasmine Zhao of Cell and Developmental Biology Microscopy Core, Perelman School of Medicine, University of Pennsylvania.
This work was financially supported by the NIH Grant R01CA191207 (L.Z. Li) and NIH grant R37CA218072 (LMPV).
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
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