TRIPODD Enables Single-Cell Quantification of Therapeutic Efficacy.

Targeted, small-molecule therapeutics have improved patient survival across cancer types, with >20 tyrosine kinase inhibitors (TKIs) receiving FDA approval as cancer therapies. While the initial TKI response is often promising, it is typically transient due to tumor evolution and subsequent therapeutic resistance driven by primary or acquired resistance mechanisms. While resistance mechanisms vary, there are currently no spatially resolved methodologies that provide a quantitative, mechanistic understanding of drug delivery and therapeutic response across therapeutic modalities (e.g., chemotherapy, radiotherapy, TKIs, immunotherapy) to enable personalized cancer therapy. Herein, we utilize our previously reported fluorescence imaging platform, Therapeutic Response Imaging through Proteomic and Optical Drug Distribution (TRIPODD), which is a quantitative protocol capable of interpreting the relationship between drug delivery and therapeutic response within the spatial context of a tumor to evaluate single-cell response and resistance to epidermal growth factor receptor TKI therapy. In this study, we applied TRIPODD to quantify the therapeutic response of EGFR-TKI-sensitive nonsmall cell lung cancer (NSCLC) xenografts to erlotinib, as a proof of concept for the platform. Through these studies, we were able to identify unique signatures of therapeutic response linked to the accumulation and engagement of erlotinib on a single-cell basis, demonstrating the utility of our TRIPODD platform technology in evaluating the treatment response and resistance at the single-cell level in heterogeneous tumors.