Abstract 4416: Impact of vaping on FoxM1-mediated chemoresistance mechanisms in lung adenocarcinoma

Abstract Background and Purpose: E-cigarette usage among students and adolescents is increasingly popular, attributed to appealing flavors, discreet usage, and the perception of being a safer alternative to traditional tobacco. However, this perception is misleading as e-cigarettes carry significant health risks, especially concerning cancer development due to the presence of carcinogenic compounds like formaldehyde, acrolein, nitrosamines, and polyaromatic hydrocarbons found in flavored e-liquids and their aerosols. These xenobiotics may impact DNA repair and cell cycle. FoxM1, a pivotal transcription factor within the forkhead box protein family, regulates genes crucial for DNA repair and cell cycle progression, such as BRCA1, BRCA2, and XRCC1. These genes are instrumental in mediating chemoresistance across various cancers via drug transporters, Wnt/β-catenin, and NOTCH signaling pathways. However, the specific impact of e-cigarette aerosol exposure on FoxM1 activity and subsequent chemoresistance is not well understood. Hence, we hypothesized that exposure to menthol-flavored e-cigarette aerosol would increase FoxM1 expression in lung adenocarcinoma cells, thus enhancing chemoresistance through Wnt/β-catenin and NOTCH signaling pathways. Methods: The human lung adenocarcinoma cell line Calu-3 was exposed to menthol-flavored e-cigarette aerosol using a Vitrocell® VC10 system, following the CORESTA recommended method No. 81. We quantitatively assessed changes in FoxM1 and its downstream effectors in the Wnt/β-catenin and NOTCH pathways using qPCR, immunoblotting, and immunohistochemistry. Results: Our results demonstrated a significant upregulation of FOXM1 at both mRNA (> 3-fold) and protein (> 1.5-fold) levels. This upregulation was correlated with increased expression of β-catenin (> 1.5-fold) and enhanced transcriptional activity of c-MYC (> 3-fold) and Cyclin D1 (> 2-fold), critical mediators of Wnt signaling. Furthermore, activation of the NOTCH signaling pathway was confirmed by the upregulation of Mastermind-like (MAML) protein (1.5-fold). Notably, siRNA-mediated knockdown of FOXM1 resulted in the downregulation of Wnt 3a (> 2-fold) and β-catenin (> 1.5-fold) levels, highlighting FoxM1's critical role in mediating the signaling pathways affected by vaping that are intricately linked to chemoresistance. Conclusion: Our findings suggest that vaping can enhance cancer chemoresistance through the activation of FoxM1 and its downstream signaling pathways. This study contributes to a deeper understanding of how lifestyle choices like vaping can impact cancer treatment outcomes, underscoring the necessity to reevaluate the perceived safety of e-cigarettes. Citation Format: Rizwana Begum, Shilpa Thota, Naveen Chintala, Biplov Sapkota, Dayanidhi Raman, Joseph Francis. Impact of vaping on FoxM1-mediated chemoresistance mechanisms in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4416.