Role of the epithelial-mesenchymal transition-related circular RNA, circ-10720, in non-small-cell lung cancer

Abstract

Background: Circular RNAs (circRNAs) are non-coding RNAs with a circular structure that have recently emerged as important regulators of tumorogenesis. Recently, several circRNAS, including circ-10720 have been related to epithelial-mesenchymal transition (EMT) process. In the present study, we have analyzed the role of circ-10720 in non-small-cell lung cancer (NSCLC) and studied its prognostic relevance in resected stage I-IIIa NSCLC patients.Methods: Circ-10720 expression was analyzed using a custom TaqMan assay in four NSCLC cell lines (HCC44, A549, H23 and H1299) and in the normal immortalized lung cell line BEAS2B. Silencing of circ-10720 was performed using two custom siRNAs which were transfected using lipofectamine 2000. Protein levels were evaluated by Western blot and immunofluorescence. Wound healing and invasion assays were performed to evaluate the impact the circRNA on cell motility. Apoptosis was analyzed by evaluation of Caspase 3-7 activity and proliferation by MTS assay. Moreover, the expression levels of the circRNA were studied in 119 resected NSCLC patients. The expression in tumor tissue was correlated with the main clinicopathological characteristics and with time to relapse (TTR).Results: Circ-10720 was overexpressed in HCC44 and A549 and underexpressed in H23 and H1299 NSCLC cell lines in comparison to BEAS2B normal immortalized lung cell line. CircRNA knockdown in the two circ-10720 overexpressing cell lines was associated with a decrease of Vimentin (VIM) and an increase of E-cadherin (CDH1) protein levels, loss of mesenchymal phenotype, and a significant reduction of migration and invasion capacity. After silencing circ-10720, the apoptosis rate increased and the proliferation was significantly reduced. Furthermore, circ-10720 was upregulated in tumor vs. normal tissue from 119 resected NSCLC patients. In the group of patients not receiving adjuvant treatment, those with high levels of circ-10720 had a shorter TTR than those with low levels and emerged as an independent prognostic value in the multivariate analysis. In tumor tissue, circ-10720 levels positively correlated with the EMT gene Twist1 levels.Conclusions: Circ-10720 regulates EMT, apoptosis and proliferation and acts as a biomarker of relapse in NSCLC. Recently, Meng et al. have described a novel circRNA, circ-10720 (CircBase ID: hsa_circ_0018189), derived from the CUL2 gene in hepatocellular carcinoma (HCC).

Phosphorylation of PFKFB4 by PIM2 promotes anaerobic glycolysis and cell proliferation in endometriosis

“…Plasmid transfection was performed according to the instructions. The transfection reagent used is lipofectamine 2000 (Invitrogen) [26].…”

Circular RNA hsa_circ_0018189 drives non‐small cell lung cancer growth by sequestering miR‐656‐3p and enhancing xCT expression

“…The regulatory role of hsa_circ_0018189 in NSCLC has been confirmed, but its specific mechanism has not been reported, 16 so we did further exploratory experiments. Starbase prediction revealed that miR‐656‐3p might interact with hsa_circ_0018189.…”

“… 12 More and more studies on circRNAs in NSCLC have proved the action of circRNAs in the occurrence and development of NSCLC. 13 , 14 , 15 Hsa_circ_0018189 was suggested to exert a significant function in NSCLC, 16 but its specific functional mechanism has not been described.…”

Exosomal ERBB2IP contributes to tumor growth via elevating PSAT1 expression in non‐small cell lung carcinoma

“…For instance, circIGF2BP3 facilitates carcinoma cell immune evasion in NSCLC 8 . CircCUL2 plays a promoting effect on NSCLC cell epithelial‐mesenchymal transition (EMT) 9 . Hsa_circ_0001492, also known as circERBB2IP, is derived from the ERBB2IP gene.…”