1. GABA(A) Receptor Activation Drives GABARAP–Nix Mediated Autophagy to Radiation-Sensitize Primary and Brain-Metastatic Lung Adenocarcinoma Tumors.
- Author
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Bhattacharya, Debanjan, Barrile, Riccardo, Toukam, Donatien Kamdem, Gawali, Vaibhavkumar S., Kallay, Laura, Ahmed, Taukir, Brown, Hawley, Rezvanian, Sepideh, Karve, Aniruddha, Desai, Pankaj B., Medvedovic, Mario, Wang, Kyle, Ionascu, Dan, Harun, Nusrat, Vallabhapurapu, Subrahmanya, Wang, Chenran, Qi, Xiaoyang, Baschnagel, Andrew M., Kritzer, Joshua A., and Cook, James M.
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PROTEINS , *ADENOCARCINOMA , *IN vitro studies , *AUTOPHAGY , *MITOCHONDRIA , *DATA analysis , *RESEARCH funding , *POLYMERASE chain reaction , *IN vivo studies , *FLUORESCENT antibody technique , *XENOGRAFTS , *DESCRIPTIVE statistics , *RADIATION-sensitizing agents , *METASTASIS , *CYTOTOXINS , *CELL lines , *IMMUNOHISTOCHEMISTRY , *KAPLAN-Meier estimator , *MOLECULAR structure , *ONE-way analysis of variance , *STATISTICS , *LUNG cancer , *STAINS & staining (Microscopy) , *CELL survival , *DATA analysis software , *CELL receptors , *GABA , *BRAIN tumors , *ELECTROPHYSIOLOGY , *IMMUNOBLOTTING , *CHEMICAL inhibitors - Abstract
Simple Summary: Non-small cell lung cancer (NSCLC) accounts for 80–85% of primary lung cancers. Radiation therapy is widely used to treat both primary NSCLC and lung cancer that has spread to the brain. However, radiotherapy responses are not durable and toxicity limits therapy. Therefore, there is an urgent need for new agents that can enhance the effectiveness of radiation therapy in lung cancer and reduce its toxicity. We find that AM-101, a benzodiazepine analog, enhances the effects of radiation and significantly improves the survival of mice with lung cancer brain-metastatic tumors. Additionally, AM-101 makes radiation treatment work better and slows down the growth of NSCLC subcutaneous xenograft tumors in mice. AM-101 activates the GABA(A) receptor in lung cancer cells, triggering selective autophagy by causing GABARAP to form multimers and stabilizing the mitochondrial receptor Nix. GABA(A) receptor activation may improve tumor control and allow for lower radiation doses, reducing toxicity. In non-small cell lung cancer (NSCLC) treatment, radiotherapy responses are not durable and toxicity limits therapy. We find that AM-101, a synthetic benzodiazepine activator of GABA(A) receptor, impairs the viability and clonogenicity of both primary and brain-metastatic NSCLC cells. Employing a human-relevant ex vivo 'chip', AM-101 is as efficacious as docetaxel, a chemotherapeutic used with radiotherapy for advanced-stage NSCLC. In vivo, AM-101 potentiates radiation, including conferring a significant survival benefit to mice bearing NSCLC intracranial tumors generated using a patient-derived metastatic line. GABA(A) receptor activation stimulates a selective-autophagic response via the multimerization of GABA(A) receptor-associated protein, GABARAP, the stabilization of mitochondrial receptor Nix, and the utilization of ubiquitin-binding protein p62. A high-affinity peptide disrupting Nix binding to GABARAP inhibits AM-101 cytotoxicity. This supports a model of GABA(A) receptor activation driving a GABARAP–Nix multimerization axis that triggers autophagy. In patients receiving radiotherapy, GABA(A) receptor activation may improve tumor control while allowing radiation dose de-intensification to reduce toxicity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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