RESUMO
Background: Long non-coding RNAs (lncRNAs) are frequently reported to involve in the onset and development of non-small cell lung cancer (NSCLC). Cisplatin (DDP) resistance continues to pose a daunting challenge for improving the prognosis of NSCLC patients. The current study intends to elucidate the molecular mechanisms underlying the function of lncRNA ZNF205 AS1/early growth response 4 (EGR4) positive feedback loop in DDP resistance of NSCLC. Methods: A series of assays, including real-time polymerase chain reaction (PCR), western blotting, flow cytometry, and dual-luciferase reporter, were performed to evaluate the effect of ZNF205-AS1/EGR4 loop in the established DDP-resistant A549 cell line and its progenitor A549 cell line. Immunohistochemistry (IHC) technique was conducted to investigate the expression pattern of EGR4 and octamer-binding protein 4 (OCT4) in NSCLC tissues. RNA pull-down assay was carried out to evaluate the interaction between miR-138-5p and EGR4 and OCT4. Transwell assay and wound healing assay was used to evaluate the invasive and migratory potential of cells subject to various treatment. The protein levels of Bcl2, Bax, Cl-caspase 3, Cl-PARP and OCT4 were measured in western blotting assay. Results: The levels of ZNF205-AS1, EGR4 and OCT4 were notably upregulated in post-chemotherapy DDP-resistant lung specimens, as opposed to those pre-chemotherapy, and in A549/DDP cells than the progenitor DDP-sensitive A549 cells. In contrast, the level of miR-138-5p was significantly reduced in A549/DDP cells (P<0.05). Luciferase reporter assay confirmed the interaction between ZNF205-AS1 and miRNA-138-5p. Protein-RNA interaction was validated between miR-138-5p, EGR4 and OCT4. The higher chemosensitivity of DDP-resistant cells induced by the loss-of-function of ZNF205-AS1 could be diminished by a miR-138-5p inhibitor. Conclusions: Our data demonstrated that miR-138-5p/OCT4 functions as a downstream effector of the ZNF205-AS1/EGR4 positive feedback loop and mediates resistance of NSCLC cells to DDP. Our work sheds light on the therapeutic strategies for NSCLC with DDP chemoresistance.
RESUMO
PD-L1 is one of the current biomarkers for immune checkpoint inhibitor (ICI) therapy in patients with non-small-cell lung cancer. However, the expression of PD-L1 in the real world and its related influencing factors remain unclear. We want to observe the expression of PD-L1 in the real world and study the related influencing factors through the collection and analysis of clinical data. R software (version 4.0) was used to perform data analysis and the "corplot" package for correlation analysis. A total of 296 individuals (mean [SD] age, 67 [9] years; 23%female) were assessed. According to the expression amount of PD-L1, the cohort was divided into low nonexpression group (PD-L1 < 1%, 26.7%), low-expression group (1% ≤ PD-L1 < 50%, 49.3%), and high-expression group (PD-L1 ≥ 50%, 23.5%). Age, gender, underlying diseases, smoking status, and PD-L1 expression level were not statistically significant. We found that the expression of PD-L1 was correlated with serum albumin (P < 0.05) and pathological type (P < 0.05) and had a negative correlation with EGFR mutation but did not correlate with gender, age, smoking status, combined with underlying diseases, tumor stage, whether it was initially treated or not, sampling site, specimen type, specimen storage time, R-IFN, CD4, CD8, NLR, CRP, and LDH. The present findings indicated that serum albumin, pathological type, and EGFR mutations are associated with PD-L1 expression in patients with NSCLC, which may provide a new basis for individualized immunotherapy and need further study to confirm. The results of this study help to further reveal the actual expression of PD-L1 in non-small-cell lung cancer patients with real events.