Waterpipe smoke condensate activates autophagy in non-tumorigenic lung epithelial cells: Implications for inflammation and stemness
4 affiliations
- 1Thumbay Research Institute for Precision Medicine, Gulf Medical University, Ajman, United Arab Emirates
- 2Molecular and Translational Medicine Laboratory, Faculty of Medicine, Beirut Arab University, Beirut, Lebanon
- 3Department Chemistry, Wayne State University, Detroit, United States of America
- 4INSERM UMR 1356, Next-Generation Immuno-Oncology Research and Therapy in Pediatric and Adult Cancer, Gustave Roussy, Faculty of Medicine, University Paris-Saclay, Villejuif, France
Abstract
Waterpipe smoking has emerged as a major global health concern, with incompletely characterized effects on bronchial epithelial cells. In this study, we investigated the cytotoxic and adaptive responses of non-tumorigenic human bronchial epithelial BEAS-2B cells exposed to waterpipe smoke condensate (WPSC). Increasing concentrations of WPSC reduced cell viability in a dose-dependent manner; however, exposure to 0.1% WPSC caused only a modest, transient reduction in viability that was no longer significant by 72 hrs and did not significantly induce apoptosis over 72 hrs, as determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and Annexin V/Propidium Iodide (PI) apoptosis assays. To elucidate the adaptive mechanisms underlying this resistance, we examined autophagic flux and found that WPSC induced time-dependent accumulation of LC3-II and p62, which was enhanced by bafilomycin A1 cotreatment, indicating the activation of autophagy. This was accompanied by increased phosphorylation of AMPK and decreased phosphorylation of mTORC1, consistent with an autophagy-mediated stress response. Functionally, the inhibition of autophagy with bafilomycin A1 increased apoptosis and necrosis, suggesting that autophagy could play a protective role. Moreover, WPSC exposure induced DNA damage, as evidenced by increased γH2AX and 53BP1 nuclear foci, and elevated proinflammatory cytokine expression (IL-1β and CCL2). Finally, WPSC treatment upregulated the expression of the cancer stem cell-associated markers CD44 and CD133. Collectively, our findings demonstrate that subcytotoxic exposure to waterpipe smoke activates autophagy in non-tumorigenic lung epithelial cells. This adaptive mechanism may represent an early cellular event linking waterpipe smoke exposure to lung carcinogenesis.
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BibTeX
@article{zaarour2026waterpipe,
title = {{Waterpipe smoke condensate activates autophagy in non-tumorigenic lung epithelial cells: Implications for inflammation and stemness}},
author = {Rania F. Zaarour and Bilal Azakir and Ayda S. Mahmood and Zohra Nizami and Husam Nawafleh and Yehya ElSayed and Salem Chouaib},
journal = {PLOS One},
year = {2026},
month = sep,
doi = {10.1371/journal.pone.0358943},
url = {https://doi.org/10.1371/journal.pone.0358943},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Waterpipe smoke condensate activates autophagy in non-tumorigenic lung epithelial cells: Implications for inflammation and stemness
AU - Rania F. Zaarour
AU - Bilal Azakir
AU - Ayda S. Mahmood
AU - Zohra Nizami
AU - Husam Nawafleh
AU - Yehya ElSayed
AU - Salem Chouaib
PY - 2026
DA - 2026/09/24
JO - PLOS One
DO - 10.1371/journal.pone.0358943
UR - https://doi.org/10.1371/journal.pone.0358943
AB - Waterpipe smoking has emerged as a major global health concern, with incompletely characterized effects on bronchial epithelial cells. In this study, we investigated the cytotoxic and adaptive responses of non-tumorigenic human bronchial epithelial BEAS-2B cells exposed to waterpipe smoke condensate (WPSC). Increasing concentrations of WPSC reduced cell viability in a dose-dependent manner; however, exposure to 0.1% WPSC caused only a modest, transient reduction in viability that was no longer significant by 72 hrs and did not significantly induce apoptosis over 72 hrs, as determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and Annexin V/Propidium Iodide (PI) apoptosis assays. To elucidate the adaptive mechanisms underlying this resistance, we examined autophagic flux and found that WPSC induced time-dependent accumulation of LC3-II and p62, which was enhanced by bafilomycin A1 cotreatment, indicating the activation of autophagy. This was accompanied by increased phosphorylation of AMPK and decreased phosphorylation of mTORC1, consistent with an autophagy-mediated stress response. Functionally, the inhibition of autophagy with bafilomycin A1 increased apoptosis and necrosis, suggesting that autophagy could play a protective role. Moreover, WPSC exposure induced DNA damage, as evidenced by increased γH2AX and 53BP1 nuclear foci, and elevated proinflammatory cytokine expression (IL-1β and CCL2). Finally, WPSC treatment upregulated the expression of the cancer stem cell-associated markers CD44 and CD133. Collectively, our findings demonstrate that subcytotoxic exposure to waterpipe smoke activates autophagy in non-tumorigenic lung epithelial cells. This adaptive mechanism may represent an early cellular event linking waterpipe smoke exposure to lung carcinogenesis.
SN - 1932-6203
ER -