FIP Virtual Seminar: Multiphoton autofluorescence imaging of immune cells in cancer

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Wed, 09/23/2020 - 12:00 to 13:00

Dr. Melissa Skala


Dr. Melissa Skala, Professor of Biomedical Engineering and Professor of Medical Physics, University of Wisconsin-Madison


Immune cells, including macrophages and T cells, have a range of cytotoxic and immune-modulating functions depending on activation state and subtype. However, current methods to assess immune cell function use exogenous labels that are limiting for time-course studies of immune cell behavior in tumors. Label-free optical imaging is an attractive solution. Here, we use multiphoton imaging of NAD(P)H and FAD, co-enzymes of metabolism, in T cells and macrophages within the tumor microenvironment. T cells were isolated from the peripheral blood of human donors, polarized to functional subsets, and subject to tumor-like media (low pH, low glucose, high lactic acid). Separately, human macrophages were co-cultured with patient-derived invasive breast cancer cells in a 3D microdevice to monitor metabolic changes with tumor-stimulated macrophage migration. NAD(P)H and FAD fluorescence intensity and lifetime were monitored on a single cell level in both systems using multiphoton microscopy. Significant differences in autofluorescence were observed between functional T cell subsets in tumor-like compared to standard media conditions, reflecting metabolic adaptations to the tumor microenvironment. Macrophages that actively migrated to the tumor cells in the 3D microfluidic model showed increased NAD(P)H/FAD intensity (optical redox ratio) compared to passively-migrating macrophages. Studies of in vivo T cell and macrophage metabolism using mouse models of cancer are underway. Altogether, these results indicate that multiphoton imaging of NAD(P)H and FAD is a powerful method for label-free, non-destructive monitoring of immune cell metabolism within single cells in the tumor microenvironment. These methods could inform new immunotherapy approaches for cancer.

Professor Melissa Skala's lab uses photonics-based technologies to develop personalized treatment plans for cancer patients (including breast, pancreatic, colorectal, neuroendocrine, oral, and other cancers). We work closely with oncologists to collect fresh patient biopsies that are maintained in 3D culture (tumor organoids), which are used to screen response to multiple treatment options for each patient. Studies across cell and animal systems are focused on tumor immunology and immunotherapy, cell-level metabolic heterogeneity, and cell-cell interactions. Collaborative projects leverage our unique imaging technologies for clinical problems including quality control in T cell and stem-cell therapies, monitoring diseases in the eye, and predicting pre-term birth, among many others. Projects are highly diverse and range from translational research to biologically-driven questions to algorithm / instrumentation development.