University of California, Laser Microbeam and Medical Program, Beckman Laser Institute and Medical Clinic, 1002 Health Sciences Road, Irvine, California 92612, United States.
University of California, Department of Molecular Biology and Biochemistry, 3205 McGaugh Hall, Irvine, California 92697-3900, United States.
J Biomed Opt. 2016 Jun 1;21(6):60503. doi: 10.1117/1.JBO.21.6.060503.
Two-photon excited fluorescence (TPEF) imaging of the cellular cofactors nicotinamide adenine dinucleotide and oxidized flavin adenine dinucleotide is widely used to measure cellular metabolism, both in normal and pathological cells and tissues. When dual-wavelength excitation is used, ratiometric TPEF imaging of the intrinsic cofactor fluorescence provides a metabolic index of cells—the “optical redox ratio” (ORR). With increased interest in understanding and controlling cellular metabolism in cancer, there is a need to evaluate the performance of ORR in malignant cells. We compare TPEF metabolic imaging with seahorse flux analysis of cellular oxygen consumption in two different breast cancer cell lines (MCF-7 and MDA-MB-231). We monitor metabolic index in living cells under both normal culture conditions and, for MCF-7, in response to cell respiration inhibitors and uncouplers. We observe a significant correlation between the TPEF-derived ORR and the flux analyzer measurements (R=0.7901, p<0.001). Our results confirm that the ORR is a valid dynamic index of cell metabolism under a range of oxygen consumption conditions relevant for cancer imaging.
双光子激发荧光（TPEF）成像技术广泛用于测量细胞代谢，包括正常和病理细胞和组织中的烟酰胺腺嘌呤二核苷酸（NADH）和氧化型黄素腺嘌呤二核苷酸（FAD）等细胞辅因子。当使用双波长激发时，固有辅因子荧光的比率 TPEF 成像提供了细胞的代谢指标——“光学氧化还原比”（ORR）。随着人们对癌症中细胞代谢理解和控制的兴趣增加，需要评估 ORR 在恶性细胞中的性能。我们比较了 TPEF 代谢成像与两种不同乳腺癌细胞系（MCF-7 和 MDA-MB-231）中海马通量分析的细胞耗氧率。我们在正常培养条件下以及 MCF-7 细胞对细胞呼吸抑制剂和解偶联剂的反应中监测活细胞中的代谢指标。我们观察到 TPEF 衍生的 ORR 与通量分析仪测量值之间存在显著相关性（R=0.7901，p<0.001）。我们的结果证实，ORR 是在与癌症成像相关的一系列耗氧条件下细胞代谢的有效动态指标。
