Related Experiment Video
Updated: Jul 10, 2026
Harnessing the Bioorthogonal Inverse Electron Demand Diels-Alder Cycloaddition for Pretargeted PET Imaging
Published on: February 3, 2015
Enhanced Response to Radiopharmaceutical Therapy in Preclinical Tumor Models with XRD-0394, a Dual Inhibitor of ATM
Abstract:
Enhanced DNA repair is a common mechanism of radiation resistance. XRD-0394, a novel small molecule dual inhibitor of ataxia telangiectasia mutated (ATM) kinase and deoxyribonucleic acid (DNA)-dependent protein kinase (DNA-PKcs), may sensitize tumor cells to killing by external beam radiation therapy (EBRT) or radiopharmaceutical therapy (RPT). DNA damage response inhibition and increased cytotoxicity were observed in Myc-CaP prostate cancer tumor cells after irradiation + XRD-0394 as indicated by the inhibition of radiation- induced phosphorylation of KAP1, p53, and H2A.X and decreased clonogenic potential. In mice bearing the FaDu head and neck squamous cell carcinoma (HNSCC) xenograft tumor model, the combination of irradiation or 177Lu-NM600 + XRD-0394 improved tumor response and overall survival compared to monotherapy controls. Increased expression of type I interferon response genes was observed after irradiation + XRD-0394 compared to irradiation alone, suggesting that XRD-0394 may also accentuate the immunogenic effects of radiation on tumor cells. Further investigation is warranted into treatment approaches that combine radiopharmaceutical therapies, DNA repair inhibitors, and immunotherapies.
Insights
A novel dual inhibitor, XRD-0394, enhances tumor cell sensitivity to radiation therapy by blocking DNA repair mechanisms. This combination therapy shows improved survival in preclinical models and may boost anti-tumor immunity.
Area of Science:
- Oncology
- Molecular Biology
- Radiotherapy Research
Background:
- Enhanced DNA repair is a key mechanism of tumor resistance to radiation therapy.
- Targeting DNA repair pathways presents a strategy to overcome radioresistance.
Purpose of the Study:
- To evaluate the efficacy of XRD-0394, a dual inhibitor of ATM and DNA-PKcs, in sensitizing tumor cells to radiation therapy.
- To assess the impact of XRD-0394 combined with external beam radiation therapy (EBRT) or radiopharmaceutical therapy (RPT) on tumor response and survival.
Main Methods:
- Investigated DNA damage response inhibition via phosphorylation markers (KAP1, p53, H2A.X) in Myc-CaP cells.
- Assessed cytotoxicity using clonogenic assays in prostate cancer cells.
- Evaluated tumor response and survival in FaDu xenograft models treated with irradiation or 177Lu-NM600 combined with XRD-0394.
Main Results:
- XRD-0394 inhibited radiation-induced DNA damage response and decreased clonogenic potential in Myc-CaP cells.
- Combination therapy of irradiation or 177Lu-NM600 with XRD-0394 improved tumor response and overall survival in HNSCC xenografts.
- XRD-0394 combined with radiation increased type I interferon response gene expression, suggesting enhanced immunogenic effects.
Conclusions:
- XRD-0394 effectively sensitizes tumor cells to radiation therapy by inhibiting DNA repair pathways.
- Combined modality treatment with XRD-0394, radiation, and potentially immunotherapy warrants further investigation for improved cancer treatment outcomes.
