Targeting 14-3-3? Overcomes Resistance to Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors in Lung Adenocarcinoma via BMP2/Smad/ID1 Signaling.

ABSTRACT: Background: The 14-3-3? protein, which acts as a putative oncoprotein, has been found to promote the proliferation, metastasis, and chemoresistance of cancer cells in several cancers including lung adenocarcinoma (LUAD); however, its significance in epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) resistance remains unknown. Methods: The Cancer Genome Atlas (TCGA) database was used to determine 14-3-3? expression in pancancer and LUAD. 14-3-3? and ID1 expression was then examined in clinical LUAD samples by immunohistochemistry (IHC). Lentiviral transfection with 14-3-3?-specific small hairpin RNA (shRNA) was used to establish stable 14-3-3? knockdown gefitinib-resistant PC9 (PC9/GR) and H1975 cell lines. The effect of 14-3-3? knockdown on reversing EGFR-TKI resistance was determined in vitro by Cell Counting Kit-8 (CCK-8), wound healing, Transwell assays, and flow cytometry. A xenograft tumor model was established to evaluate the role of 14-3-3? in EGFR-TKI resistance. Microarray analysis results showed multiple pathways regulated by 14-3-3?-shRNA. Results: In the present study, we demonstrated that based on the TCGA, pancancer and LUAD 14-3-3? expression was elevated and predicted unfavorable prognosis. In addition, high 14-3-3? expression was associated with advanced T stage, TNM stage, presence of lymph node metastasis and, importantly, poor treatment response to EGFR-TKIs in LUAD patients with EGFR-activating mutations. 14-3-3? shRNA sensitized EGFR-TKI-resistant human LUAD cells to gefitinib and reversed epithelial-to-mesenchymal transition (EMT). After 14-3-3? depletion, bone morphogenetic protein (BMP) signaling activation was decreased in EGFR-TKI-resistant cells in microarray analysis, which was further validated by Western blot analysis. Furthermore, the expression of 14-3-3? positively correlates with ID1 expression in human EGFR-mutant LUAD patient samples. In vivo, there was a reduction in the tumor burden in mice treated with 14-3-3? shRNA and gefitinib compared to mice treated with gefitinib alone. Conclusion: Our work uncovers a hitherto unappreciated role of 14-3-3? in EGFR-TKI resistance. This study might provide a potential therapeutic approach for treating LUAD patients harboring EGFR mutations.

SUBMITTER: Cui J 

PROVIDER: S-EPMC7571474 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature