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Updated: Jun 23, 2025
A Multiplexed Luciferase-based Screening Platform for Interrogating Cancer-associated Signal Transduction in Cultured Cells
Published on: July 3, 2013
GAS-Luc2 Reporter Cell Lines for Immune Checkpoint Drug Screening in Solid Tumors
Hyeyoun Chang1, John G Foulke1, Luping Chen1
1American Type Culture Collection (ATCC), Manassas, VA 20110, USA.
Abstract:
Recent studies highlight the integral role of the interferon gamma receptor (IFNγR) pathway in T cell-mediated cytotoxicity against solid but not liquid tumors. IFNγ not only directly facilitates tumor cell death by T cells but also indirectly promotes cytotoxicity via myeloid phagocytosis in the tumor microenvironment. Meanwhile, full human ex vivo immune checkpoint drug screening remains challenging. We hypothesized that an engineered gamma interferon activation site response element luciferase reporter (GAS-Luc2) can be utilized for immune checkpoint drug screening in diverse ex vivo T cell-solid tumor cell co-culture systems. We comprehensively profiled cell surface proteins in ATCC's extensive collection of human tumor and immune cell lines, identifying those with endogenously high expression of established and novel immune checkpoint molecules and binding ligands. We then engineered three GAS-Luc2 reporter tumor cell lines expressing immune checkpoints PD-L1, CD155, or B7-H3/CD276. Luciferase expression was suppressed upon relevant immune checkpoint-ligand engagement. In the presence of an immune checkpoint inhibitor, T cells released IFNγ, activating the JAK-STAT pathway in GAS-Luc2 cells, and generating a quantifiable bioluminescent signal for inhibitor evaluation. These reporter lines also detected paracrine IFNγ signaling for immune checkpoint-targeted ADCC drug screening. Further development into an artificial antigen-presenting cell line (aAPC) significantly enhanced T cell signaling for superior performance in these ex vivo immune checkpoint drug screening platforms.
Insights
This study introduces a novel reporter system for evaluating immune checkpoint inhibitors. The engineered cells enable efficient ex vivo drug screening by measuring T cell-mediated tumor cell death and interferon gamma signaling.
Area of Science:
- Immunology
- Oncology
- Biotechnology
Background:
- The interferon gamma receptor (IFNγR) pathway is crucial for T cell cytotoxicity against solid tumors.
- Ex vivo screening of immune checkpoint drugs using human cell lines is challenging.
- Immune checkpoints regulate T cell activity and tumor immune evasion.
Purpose of the Study:
- To develop and validate an engineered reporter system for ex vivo immune checkpoint drug screening.
- To utilize a gamma interferon activation site response element luciferase reporter (GAS-Luc2) for quantifying drug efficacy.
- To engineer tumor cell lines expressing key immune checkpoints for co-culture assays.
Main Methods:
- Engineered GAS-Luc2 reporter tumor cell lines expressing PD-L1, CD155, or B7-H3/CD276.
- Profiling of cell surface proteins to identify suitable cell lines for engineering.
- Co-culture assays with T cells and reporter tumor cells in the presence of immune checkpoint inhibitors.
- Measurement of bioluminescent signals generated by the GAS-Luc2 reporter system.
- Development of artificial antigen-presenting cells (aAPCs) to enhance T cell signaling.
Main Results:
- Engineered reporter cell lines demonstrated suppressed luciferase expression upon immune checkpoint-ligand engagement.
- The system successfully quantified interferon gamma (IFNγ) release from T cells upon inhibitor treatment.
- Reporter lines detected paracrine IFNγ signaling for antibody-dependent cell-mediated cytotoxicity (ADCC) drug screening.
- Artificial antigen-presenting cells significantly enhanced T cell signaling for improved screening performance.
Conclusions:
- The GAS-Luc2 reporter system provides a robust platform for ex vivo immune checkpoint drug screening.
- This approach facilitates the evaluation of T cell-mediated cytotoxicity and IFNγ signaling in response to novel therapeutics.
- The engineered cell lines and aAPC technology offer a promising avenue for advancing cancer immunotherapy drug development.
