[The role of RUNX1 in the apoptosis of epithelial cells in nasal polyps]

Objective: To explore the expression of Runt-related transcription factor 1 (RUNX1) in nasal polyps (NPs) tissues and the potential role on apoptosis of primary human nasal epithelial cells (pHNECs) in NPs. Methods: The expression level of RUNX1 in NPs tissues was determined by Western blot (WB) and immunohistochemical staining (IHC). In vitro, TNF-α (20 ng/ml) was used to stimulate pHNECs to establish the apoptosis injury model. Hoechst staining was performed to observe pHNECs apoptosis by kit. Subsequently, quantitative real-time PCR (qRT-PCR) and WB were utilized to detect the expression of apoptosis-related proteins B-cell lymphoma-2 (BCL-2), BCL2-associated X (BAX) and cysteinyl aspartate specific proteinase-3 (Caspase-3) to assess the level of apoptosis. The plasmid of sh-RUNX1-6 was transfected into the pHNECs apoptosis model, then the effect of RUNX1 silence on apoptosis was evaluated by WB and flow cytometry. Statistical analysis was performed by the SPSS 19.0 and GraphPad Prism5 software. Results: The expression of RUNX1 in NPs tissue was significantly higher than that in inferior turbinates, and the difference was statistically significant (0.274±0.042 vs 0.110±0.027, t=9.675, P<0.05). Compared with the inferior turbinates, BAX and Caspase-3 expressions were increased whereas BCL-2 was decreased in NPs, and the differences were statistically significant (BAX 0.346±0.032 vs 0.302±0.037, Caspase-3 0.228±0.061 vs 0.158±0.065, BCL-2 0.090±0.047 vs 0.276±0.057, t value was 2.680, 2.361 and 7.575, respectively, all P<0.05). The expression levels of RUNX1 and apoptosis in pHNECs increased in a time-dependent manner after TNF-α exposure (P<0.05). Plasmid of sh-RUNX1-6 transfected silenced the expression of RUNX1 in pHNECs treated by TNF-α. After silencing RUNX1 in pHNECs apoptosis model, the protein levels of BAX and Caspase-3 were decreased, while the expression of BCL-2 was increased, the rate of apoptosis was decreased (P<0.05). Conclusions: RUNX1 is increased in NPs. Silencing RUNX1 can inhibit the apoptosis and reduce cell inflammatory damage of pHNECs induced by TNF-α.