The capacity of cancer cells to adjust their metabolism to thrive in new environments and in response to treatments has been implicated in the acquisition of treatment resistance. To optimize therapeutic strategies such as photodynamic therapy (PDT)-based combination treatments, methods to characterize the plasticity of cancer metabolism in response to treatments are required. This protocol provides a method for high-throughput and label-free tracking of metabolic redox states in cancer tissues, leveraging the autofluorescent properties of nicotinamide dinucleotide (NAD(P)H) and oxidized flavoprotein adenine dinucleotide (FAD). The methodology is optimized to be applied to 3D spheroid/microtumor/organoid cultures, regardless of the culture type (e.g., adherent or suspension cultures) and morphology. The exploitation of these methods may elucidate mechanisms of metabolic adaptation and perturbations in redox homeostasis, and chart the overall tumor health in both 3D culture models and ex vivo tissues following cancer therapies, such as PDT.
Keywords: High-throughput screening; Metabolic plasticity; Optical redox ratio; Oxidative phosphorylation; Oxidative stress; Spheroids.
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