miR-19b enhances proliferation and apoptosis resistance via the EGFR signaling pathway by targeting PP2A and BIM in non-small cell lung cancer

Abstract

BackgroundEpidermal growth factor receptor (EGFR) mutations enable constitutive active downstream signaling of PI3K/AKT, KRAS/ERK and JAK/STAT pathways, and promote tumor progression by inducing uncontrolled proliferation, evasion of apoptosis and migration of non-small cell lung cancer (NSCLC). In addition, such EGFR mutations increase the susceptibility of patients with NSCLC to tyrosine kinase inhibitor (TKI) therapy, but treated patients will invariably relapse with resistant disease. A global understanding of underlying molecular mechanisms of EGFR signaling may improve the management of NSCLC patients.Methodsmicroarray analysis was performed to identify PI3K/AKT-regulated miRNAs. Phosphoproteomic analysis and cell based assays were performed using NSCLC cell lines lentivirally transduced with anti-miR or miR overexpressing constructs.ResultsHere, we show that 17 miRNAs including members of the miR-17~ 92 cluster are dysregulated following PI3K/AKT inhibition of EGFR mutant NSCLC cells. Bioinformatics analysis revealed that dysregulated miRNAs act in a concerted manner to enhance the activity of the EGFR signaling pathway. These findings were closely mirrored by attenuation of miR-17~ 92 family member miR-19b in NSCLC cell lines which resulted in reduced phosphorylation of ERK, AKT and STAT and effector proteins in EGFR mutant NSCLC cells. Consistent with this finding, cell cycle progression, clonogenic growth and migration were reduced and apoptosis was enhanced. Co-treatment of NSCLC cells with the tyrosine kinase inhibitor (TKI) gefitinib and anti-miR-19b construct reduced migration and clonogenic growth in a synergistic manner suggesting that EGFR and miR-19b act together to control oncogenic processes. Serine/threonine phosphatase PP2A subunit PPP2R5E and BCL2L11 encoding BIM were identified as major targets of miR-19b by target validation assays. Consistent with this finding, PP2A activity was strongly enhanced in NSCLC transduced with anti-miR-19b construct, but not in cells co-transduced with anti-miR-19b and shPPP2R5E, suggesting that PPP2R5E is a major constituent of the PP2A complex. Accordingly, enhanced proliferation by miR-19b was due to targeting PPP2R5E. In contrast, apoptosis resistance was mainly due to targeting BCL2L11.ConclusionOur results provide insight into the importance of targeting PPP2R5E and BCL2L11 by miR-19b in oncogenic processes of NSCLC. Attenuation of miR-19b expression could potentially be exploited in adjuvant therapy of EGFR mutant NSCLC.Electronic supplementary materialThe online version of this article (10.1186/s12943-018-0781-5) contains supplementary material, which is available to authorized users.

Systematic screening identifies a 2‐gene signature as a high‐potential prognostic marker of undifferentiated pleomorphic sarcoma/myxofibrosarcoma

“…PP2A is a serine/threonine (Ser/Thr) protein phosphatase, which has a heterotrimeric structure formed by a catalytic subunit (PP2Ac), an A subunit and a member of the B subunit family . The tumour suppressor role of PP2A has been reported in several types of human cancer, such as colorectal cancer, non‐small cell lung cancer, leukemia and sarcoma . Using data in other TCGA cohorts, we found that ITGA10 might be associated with unfavourable RFS in LAML, PRAD and UVM and unfavourable OS in KIRP, LGG and THCA.…”

Radon Biomonitoring and microRNA in Lung Cancer

“…The levels of miR-19b-3p in blood plasma of lung cancer patients were significantly higher compared to the healthy control group. In NSCLC cell lines miR-19b potentiates cell proliferation and inhibit apoptosis by targeting PP2A B subunit PPP2R5E and BCL2L11 [97]. However, statistically significant differences in the expression level of miR-19b-3p in cancer patients exposed to prolonged exposure to radon and living in areas with low radon levels were not found [98].…”

Two-hybrid screening of FAM13A protein partners in lung epithelial cells

“…Heat shock cognate 71 kDa protein HSPA8 A Involved in CFTR biogenesis and trafficking [20] Regulated by corticoid in cell lysate of sputum of COPD patients [21] Serine/threonine-protein phosphatase 2A 56 kDa regulatory subunit epsilon isoform* PPP2R5E* A Genetically associated with lung cancer [22] PP2A activity was strongly enhanced in NSCLC [23] TBC1 domain family member 5 TBC1D5 A Induced by smoking and ozone (murine COPD model) [24] Filamin-B FLNB C No 14-3-3 protein beta/alpha YWHAB C Interact with and regulate surfactant protein A2 [25] Involved in lung cancer [26] Enhancer of mRNA-decapping protein 4 EDC4 C No 14-3-3 protein zeta/delta YWHAZ E Identified as a metastasis enhancer gene in lung cancer [32] Upregulated in lung cancer [33] Differentially expressed in malignant bronchial epithelial cell line compared to control cell line [34] More frequent increased expression in patients with resectable lung adenocarcinoma with an improved prognosis [35] 26S proteasome non-ATPase regulatory subunit 11 PSMD11 F Differentially expressed in malignant bronchial epithelial cell line compared to control cell line [34] Fig . 1 Diagram of the proteins identified in the two-hybrid screening and their interaction domains Fig.…”