Longitudinal FRET Imaging of Glucose and Lactate Dynamics and Response to Therapy in Breast Cancer Cells

Abstract

The reprogramming of cellular metabolism is a hallmark of cancer. The ability to noninvasively assay glucose and lactate concentrations in cancer cells would improve our understanding of the dynamic changes in metabolic activity accompanying tumor initiation, progression, and response to therapy. Unfortunately, common approaches for measuring these nutrient levels are invasive or interrupt cell growth. This study transfected FRET reporters quantifying glucose and lactate concentration into breast cancer cell lines to study nutrient dynamics and response to therapy. Procedures: Two FRET reporters, one assaying glucose concentration and one assaying lactate concentration, were stably transfected into the MDA-MB-231 breast cancer cell line. Correlation between FRET measurements and ligand concentration were measured using a confocal microscope and a cell imaging plate reader. Longitudinal changes in glucose and lactate concentration were measured in response to treatment with CoCl 2 , cytochalasin B, and phloretin which, respectively, induce hypoxia, block glucose uptake, and block glucose and lactate transport. Results: The FRET ratio from the glucose and lactate reporters increased with increasing concentration of the corresponding ligand (p < 0.005 and p < 0.05, respectively). The FRET ratio from both reporters was found to decrease over time for high initial concentrations of the ligand (p < 0.01). Significant differences in the FRET ratio corresponding to metabolic inhibition were found when cells were treated with glucose/lactate transporter inhibitors. Conclusions: FRET reporters can track intracellular glucose and lactate dynamics in cancer cells, providing insight into tumor metabolism and response to therapy over time.

Comparing mechanism-based and machine learning models for predicting the effects of glucose accessibility on tumor cell proliferation

“…Knowing such a relationship would enable the model to perform predictions at doses not yet tested. Another area for improvement would be to employ time-resolved, non-invasive imaging to track the nutrient level in the cells; we have attempted to develop such a technique based on FRET reporters transfected into the MDA-MB-231 cell line 53 , but it only provides a relative measure of glucose and lactate concentrations. The absolute measurement of the dynamics of lactate concentration would also allow us to include more details in tumor cell metabolism in the model.…”

A Graph-Based Framework for Multiscale Modeling of Physiological Transport

“…The governing equations of the flow distribution and the mathematical formulation of the discrete model of advection-diffusion-reaction physics are presented (Sections 2.3,2.4,2.5). We use our framework to model two physiologically relevant test systems: 1) advection-dispersion dynamics of glucose transport in the microvasculature and 2) advection-dispersion-reaction dynamics of glucose-lactate exchange in the functionally coupled tissue-vascular domains (glucose-lactate dynamics is relevant in tumor metabolism where metabolic activity alters in tumor microenvironments (Yang et al, 2021) and in modeling fuel-stimulated insulin secretion (Jiang et al, 2007;Prentki et al, 2013)). By applying our method, we predict glucose drift in the islet vasculature and cross-validate the flow and concentration fields of the multiphysics simulation with COMSOL simulations (Section 3.1.1).…”