Abstract
Abstract
Background: Non-small cell lung cancer (NSCLC) is one of the most common types of cancer diagnosis among men and women leads the most cancer-related deaths in the United States. This is largely due to treatment failure which arises from therapy-resistant tumors. The current study investigates the role of muscarinic acetylcholine receptor 3 (CHRM3) in the development and treatment of NSCLC chemotherapy-resistance and the potential of the overactive bladder CHRM3 antagonist darifenacin to treat this lethal form of cancer.
Methods: Human NSCLC cell cultures were used to harvest protein for Western blot analyses of protein expression and activity of intracellular pathways. The chemotherapy drug docetaxel’s (DTX) ability to induce apoptosis was measured with crystal violet survival assay and colony formation assay.
Results: CHRM3 expression was measured in chemonaive NSCLC cells (A549) and chemoresistant cells (A549R), which showed increased expression in A549R cells. Chemoresistant A549R were pretreated with the CHRM3 antagonist darifenacin (Dari, 10 μM, 24 hrs) before treatment with DTX (48 hrs). Crystal violet survival assay and colony formation assays showed a significant reduction in cell survival in the Dari + DTX combination treatment group suggesting that CHRM3 signaling is necessary in a chemoresistant state. Chemonaive A549 cells and CHRM3 overexpressing A549 cells (A549 M3OE) were pretreated with carbachol (10 µM, 24 hrs) to activate CHRM3 before treatment with a set of serial dilutions of DTX (48 hrs). Crystal violet survival assay results showed that carbachol was not able to protect either cell line from DTX-induced cell death, suggesting that CHRM3 signaling alone is not sufficient to induce a chemoresistant state.
Conclusion: CHRM3 overexpression is observed in chemoresistant forms of NSCLC. While activation of CHRM3 does not instill a resistant state in chemonaive cells, its signaling is essential for maintenance of the chemoresistant state. The repurposing of the CHRM3 antagonist darifenacin shows strong potential as a therapeutic to treat lethal chemoresistant forms of NSCLC.The project described was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under Grant #P20GM103408
Citation Format: Joslyn Bassett, Tyler Bland. Repurposing an overactive bladder drug to treat chemoresistant lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1090.