Comparative analysis of molecular targeted radiosensitizers in 2D and 3D cancer cell line models.
Despite being a critical treatment modality, radiotherapy effectiveness is often limited by tumor resistance. Therefore, there exists a need to identify molecular targeted drugs that enhance the therapeutic response to radiation. We hypothesize that a systematic comparison of targeted radiosensitizers across two-dimensional (2D) and three-dimensional (3D) spheroid cultures will reveal context-specific differences in radiosensitivity to guide preclinical prioritization of candidate radiosensitizers.
Radiosensitizing effects of DNA-PKcs (M3814), ATR (M6620), PARP (Olaparib), and IAP (Birinapant) inhibitors using a panel of lung cancer cell lines were studied. A 3D extracellular matrix (ECM) colony formation assay for single doses of 0-6 Gy, coupled with automated colony counting, was implemented alongside standard 2D colony formation assays. Dose Enhancement Factor (DEF0.1SF) was used to compare radiosensitizing effects, and drug-radiation interactions were assessed using the Synergyfinder tool.
DNA-PKcs and ATR inhibitors induced moderate to strong dose-dependent radiosensitization (DEF0.1SF > 1.4 for at least one drug concentration) in most cell lines under both conditions (15/16 drug/cell line combinations). PARP inhibition showed similar effects in 3D and 2D (2/3 vs 3/5 combinations). Birinapant showed no relevant effect. The strongest synergy was at 2 Gy, particularly with the DNA-PK inhibitor in both culture models.
Integrating multiple culture models enhances the detection of cell line - and drug-specific radiosensitization. Although 2D and 3D cultures produced largely similar results, and 2D assays provide a practical alternative when 3D methods are not feasible, the 3D cultures reveal additional ECM-dependent responses. These results emphasize the utility of physiologically relevant platforms for robust screening and prioritization of candidate radiosensitizers.
Radiosensitizing effects of DNA-PKcs (M3814), ATR (M6620), PARP (Olaparib), and IAP (Birinapant) inhibitors using a panel of lung cancer cell lines were studied. A 3D extracellular matrix (ECM) colony formation assay for single doses of 0-6 Gy, coupled with automated colony counting, was implemented alongside standard 2D colony formation assays. Dose Enhancement Factor (DEF0.1SF) was used to compare radiosensitizing effects, and drug-radiation interactions were assessed using the Synergyfinder tool.
DNA-PKcs and ATR inhibitors induced moderate to strong dose-dependent radiosensitization (DEF0.1SF > 1.4 for at least one drug concentration) in most cell lines under both conditions (15/16 drug/cell line combinations). PARP inhibition showed similar effects in 3D and 2D (2/3 vs 3/5 combinations). Birinapant showed no relevant effect. The strongest synergy was at 2 Gy, particularly with the DNA-PK inhibitor in both culture models.
Integrating multiple culture models enhances the detection of cell line - and drug-specific radiosensitization. Although 2D and 3D cultures produced largely similar results, and 2D assays provide a practical alternative when 3D methods are not feasible, the 3D cultures reveal additional ECM-dependent responses. These results emphasize the utility of physiologically relevant platforms for robust screening and prioritization of candidate radiosensitizers.
Authors
Ramirez Parra Ramirez Parra, Dietrich Dietrich, Pfeifer Pfeifer, Willers Willers, Krause Krause, Borgeaud Borgeaud
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