HSA_CIRC_0004050 on proliferation and apoptosis of A549 cells through ERK/JNK signaling pathway.

The aim of this study was to screen the differentially expressed circular ribonucleic acid (circRNA) in non-small cell lung cancer (NSCLC) and explore its functional mechanism. Differentially expressed circRNAs in tumor tissues of NSCLC patients were detected via gene microarray and reverse transcriptionquantitative polymerase chain reaction (RT-qPCR). The associaton between their expressions and the clinical phenotypes was explored combined with clinical data. The effect of overexpression of hsa_circ_0004050 on the proliferation of A549 cells was detected via cell counting kit-8 (CCK-8) assay and CFSE assay. The effect of overexpression of hsa_circ_0004050 (human circular ribonucleic acid_0004050) on the apoptosis of A549 cells was detected using the Annexin V-FITC/PI kit. Then the direct-acting miRNAs of hsa_circ_0004050 were screened using bioinformatics software and luciferase reporter assay, and the direct targets of miR- 1233-3p were explored using bioinformatics software and luciferase reporter assay combined with RTqPCR and Western blotting. The effects of overexpression of miR-1233-3p or knockdown of dual specificity phosphatase 9 (DUSP9) on the cell proliferation and apoptosis affected by overexpression of hsa_circ_0004050 were detected. Western blotting was performed to detect the effects of hsa_circ_0004050 on the extracellular signal-regulated kinase (ERK)/c-Jun N-terminal kinase (JNK) signaling pathway. The expression of hsa_ circ_0004050 was significantly lower in tumor tissues than that in para-carcinoma tissues in NSCLC patients. The expression of hsa_circ_0004050 was significantly correlated with TNM stage, tumor size and lymph node metastasis. The results of survival analysis showed that the survival time of patients with a high expression of hsa_circ_0004050 was obviously prolonged. According to the results of phenotype assay, hsa_circ_0004050 could promote apoptosis and inhibit proliferation of A549 cells. In terms of its mechanism, hsa_circ_0004050 could markedly increase the protein expression of DUSP9 via targeting miR-1233-3p in A549 cells, thereby inhibiting the ERK/JNK signaling pathway. Hsa_circ_0004050 may serve as a potential therapeutic target for NSCLC or a biomarker for the diagnosis of NSCLC in the future.