Lanjun Wang1, Mengqi Li2, Rong Lian3. 1. Central Laboratory, the Fist Affiliated Hospital of Xinxiang Medical College, Weihui, Henan, China. wljhn0908@126.com. 2. Department of Cardiovascular Division, the Fist Affiliated Hospital of Xinxiang Medical College, Weihui, Henan, China. 3. Department of Otolaryngology, the Fist Affiliated Hospital of Xinxiang Medical College, Weihui, Henan, China.
Abstract
BACKGROUND: Circular RNAs (circRNAs) expression profile has been reported in lung adenocarcinoma (LUAD) cells resistant to gefitinib, and hsa_circ_0000567 was abnormally upregulated. However, its precise role in gefitinib resistance remains unclarified. METHODS: Levels of hsa_circ_0000567, microRNA (miR)-377-3p and zinc finger protein X-linked (ZFX) were detected by real-time quantitative PCR. Direct attachment was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation assay. Gefitinib resistance was measured by MTT assay, colony formation assay, flow cytometry, western blotting, and xenograft in mice. RESULTS: Expression of hsa_circ_0000567 was upreguated in human gefitinib-resistant human LUAD tissues and cells (HCC827/GR and PC9/GR). Clinically, higher hsa_circ_0000567 correlated with advanced tumor burden. Blockage of hsa_circ_0000567 suppressed cell viability, half maximal inhibitory concentration (IC₅₀) value, colony formation ability, and expression of Bcl-2 and proliferating cell nuclear antigen (PCNA) in HCC827/GR and PC9/GR cells under gefitinib treatment or not, accompanied with enhanced apoptosis rate and Bax expression. In vivo, tumor growth of PC9/GR cells untreated and treated with gefitinib was restrained by silencing hsa_circ_0000567. miR-377-3p was directly regulated by hsa_circ_0000567, and then targeted ZFX. Similar to hsa_circ_0000567 knockdown, overexpressing miR-377-3p inhibited chemoresistance in genitinib-resistant LUAD cells in vitro, whereas, depleting miR-377-3p was able to promote gefitinib resistance in spite of hsa_circ_0000567 knockdown. Moreover, restoring ZFX abrogated miR-377-3p-mediated chemosensitivity in genitinib-resistant LUAD cells in vitro. CONCLUSION: The hsa_circ_0000567/miR-377-3p/ZFX axis might contribute to acquired gefitinib resistance in LUAD cells both in vitro and in vivo, suggesting hsa_circ_0000567 as a novel therapeutic target in treatment of gefitinib-resistant LUAD.
BACKGROUND: Circular RNAs (circRNAs) expression profile has been reported in lung adenocarcinoma (LUAD) cells resistant to gefitinib, and hsa_circ_0000567 was abnormally upregulated. However, its precise role in gefitinib resistance remains unclarified. METHODS: Levels of hsa_circ_0000567, microRNA (miR)-377-3p and zinc finger protein X-linked (ZFX) were detected by real-time quantitative PCR. Direct attachment was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation assay. Gefitinib resistance was measured by MTT assay, colony formation assay, flow cytometry, western blotting, and xenograft in mice. RESULTS: Expression of hsa_circ_0000567 was upreguated in human gefitinib-resistant human LUAD tissues and cells (HCC827/GR and PC9/GR). Clinically, higher hsa_circ_0000567 correlated with advanced tumor burden. Blockage of hsa_circ_0000567 suppressed cell viability, half maximal inhibitory concentration (IC₅₀) value, colony formation ability, and expression of Bcl-2 and proliferating cell nuclear antigen (PCNA) in HCC827/GR and PC9/GR cells under gefitinib treatment or not, accompanied with enhanced apoptosis rate and Bax expression. In vivo, tumor growth of PC9/GR cells untreated and treated with gefitinib was restrained by silencing hsa_circ_0000567. miR-377-3p was directly regulated by hsa_circ_0000567, and then targeted ZFX. Similar to hsa_circ_0000567 knockdown, overexpressing miR-377-3p inhibited chemoresistance in genitinib-resistant LUAD cells in vitro, whereas, depleting miR-377-3p was able to promote gefitinib resistance in spite of hsa_circ_0000567 knockdown. Moreover, restoring ZFX abrogated miR-377-3p-mediated chemosensitivity in genitinib-resistant LUAD cells in vitro. CONCLUSION: The hsa_circ_0000567/miR-377-3p/ZFX axis might contribute to acquired gefitinib resistance in LUAD cells both in vitro and in vivo, suggesting hsa_circ_0000567 as a novel therapeutic target in treatment of gefitinib-resistant LUAD.
Authors: Ling Cai; Yi-Hsuan Tsai; Ping Wang; Jun Wang; Dongxu Li; Huitao Fan; Yilin Zhao; Rohan Bareja; Rui Lu; Elizabeth M Wilson; Andrea Sboner; Young E Whang; Deyou Zheng; Joel S Parker; H Shelton Earp; Gang Greg Wang Journal: Mol Cell Date: 2018-09-27 Impact factor: 17.970