Novel circular RNA hsa_circ_0036683 suppresses proliferation and migration by mediating the miR-4664-3p/CDK2AP2 axis in non-small cell lung cancer.

The aim of the present study was to investigate the function of novel circular RNA hsa_circ_0036683 (circ-36683) in non-small cell lung cancer (NSCLC). RNA sequencing was used to screen out differentially expressed miRNAs. Expression levels of miR-4664-3p and circ-36683 were evaluated in lung carcinoma cells and tissues by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The effects of miR-4664-3p and circ-36683 on proliferation and migration were assessed using cell counting kit-8 (CCK-8), wound healing and transwell migration assays and xenograft experiments. The targeting relationship of circ-36683/miR-4664-3p/CDK2AP2 was assessed by luciferase reporter assays, western blot, qRT-PCR and argonaute2-RNA immunoprecipitation (AGO2 RIP). Co-immunoprecipitation (Co-IP), 5-ethynyl-2'-deoxyuridine (EdU) staining and CCK-8 were used to validate the indispensable role of CDK2AP2 in suppressing cell proliferation as a result of CDK2AP1 overexpression. By RNA sequencing, miR-4664-3p was screened out as an abnormally elevated miRNA in NSCLC tissues. Transfection of miR-4664-3p could promote cell proliferation, migration and xenograft tumor growth. As a target of miR-4664-3p, CDK2AP2 expression was downregulated by miR-4664-3p transfection and CDK2AP2 overexpression could abolish the proliferation promotion resulting from miR-4664-3p elevation. Circ-36683, derived from back splicing of ABHD2 pre-mRNA, was attenuated in NSCLC tissue and identified as a sponge of miR-4664-3p. The functional study revealed that circ-36683 overexpression suppressed cell proliferation, migration and resulted in G0/G1 phase arrest. More importantly, the antioncogenic function of circ-36683 was largely dependent on the miR-4664-3p/CDK2AP2 axis, through which circ-36683 could upregulate the expression of p53/p21/p27 and downregulate the expression of CDK2/cyclin E1. The present study revealed the antioncogenic role of circ-36683 in suppressing cell proliferation and migration and highlighted that targeting the circ-36683/miR-4664-3p/CDK2AP2 axis is a promising strategy for the intervention of NSCLC.

Liu R ，Zhang H ，Xin J ，Xie SY ，Jiao F ，Li YJ ，Chu MY ，Qiu J ，Yan YF ... -  《-》

Hsa_circ_0125356 promotes gemcitabine resistance by modulating WNT canonical and non-canonical pathways via miR-582-5p/FGF9 axis in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is the leading cause of cancer morbidity and mortality worldwide. The prognosis of patients has been significantly improved by chemotherapy, but acquired drug resistance remains a major obstacle to NSCLC treatment. Circular RNAs (circRNAs), which act as miRNA or protein sponges, are critically associated with the development and chemotherapy resistance of NSCLC. CircRNA sequencing was performed to analyze the differential expression of circRNAs between A549 and A549-GR cells. Chromogenic in situ hybridization (CISH) and immunohistochemistry (IHC) technologies were used to detect the expression of hsa_circ_0125356, miR-582-5p,and FGF9 in NSCLC tissues and para-carcinoma tissues. Fluorescence in situ hybridization (FISH), dual-luciferase reporter assays and RNA immunoprecipitation (RIP) were conducted to evaluate the expression and regulation of hsa_circ_0125356, miR-582-5p, and FGF9. Furthermore, the regulation of hsa_circ_0125356/miR-582-5p/FGF9 on gemcitabine sensitivity was confirmed by TUNEL, Transwell, EdU, CCK8 and immunohistochemistry. We identified a novel hsa_circ_0125356 as a therapeutic target against gemcitabine resistance. Hsa_circ_0125356 was significantly elevated in clinical samples of patients with NSCLC. Moreover, hsa_circ_0125356 overexpression promoted gemcitabine resistance to NSCLC by upregulating FGF9 via sponging miR-582-5p in vivo and in vitro. Notably, WNT canonical (ERK/GSK3β/β-catenin) and non-canonical (Daam1/RhoA/ROCK2) signaling pathways were activated due to hsa_circ_0125356 acting as an endogenous miR-582-5p sponge to regulate the expression of FGF9, and thereby enhancing gemcitabine resistance via promoting DNA damage repair and inhibition of apoptosis. The results were further confirmed by two small molecule antagonists, WAY 316606 and XAV-939,which could inhibit the activation of WNT signaling pathway induced by hsa_circ_0125356. We first demonstrated that hsa_circ_0125356 was significantly upregulated and served as a biomarker for gemcitabine resistance in NSCLC by sponging miR-582-5p/FGF9 axis to regulate the WNT canonical and non-canonical signaling pathways, which provided a new direction for identification of therapeutic targets for the treatment of gemcitabine resistance of NSCLC.

Du X ，Luo W ，Li H ，Gu Q ，Huang P ，Wang C ，Li N ，Liu F ，Xia C ... -  《Molecular Cancer》

Circ_BLNK is a Unique Molecular Marker in Non-small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) patients are characterized by distant metastasis and poor prognosis. Growing evidence has implied that circular RNAs (circRNAs) are involved in multiple tumor progression, including NSCLC. The objective of the present study was to functionally dissect the role and mechanism of circ_BLNK in NSCLC development and progression. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression of circ_BLNK, miR-942-5p, and forkhead box protein O1 (FOXO1) in NSCLC tissues and cells. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay and colony formation assay detected cell proliferation; the protein expression levels were tested by western blot assay; cell apoptosis was measured by flow cytometry, and transwell assay detected cell migration and invasion. The molecular targeting relationship was determined by dual-luciferase reporter assay. The effect of circ_BLNK overexpression on tumor growth was detected by in vivo experiments and immunohistochemistry. Circ_BLNK was dramatically decreased in NSCLC, and overexpression of circ_BLNK inhibited proliferation, migration, and invasion of NSCLC cells and promoted cell apoptosis. Circ_BLNK level was negatively correlated with miR-942-5p expression and positively correlated with FOXO1 expression. Moreover, circ_BLNK acted as a sponge for miR-942-5p, which targeted FOXO1. Rescue assays presented that miR-942-5p reversed the anticancer action of circ_BLNK in NSCLC. Besides that, miR-942-5p inhibition suppressed the oncogenic behaviors, which were attenuated by FOXO1 knockdown. Animal experiments exhibited that circ_BLNK upregulation repressed tumor growth in vivo. Our study demonstrated a novel regulatory mechanism that circ_BLNK/miR-942-5p/FOXO1 axis adjusted non-small cell lung cancer development.

Hong H ，Ding D ，Zhang Y ，Chen Y ，Chen S ，Jiang M ，Zhang H ，Wang Q ，Hu Y ，He J ，Yuan J ... -  《-》

Hsa_circ_0087784 enhances non-small cell lung cancer progression via the miR-576-5p/CDCA4 axis.

Shang B ，Li L ，Wang G ，Liu G ，Yang X ，Gao J ，Yin W ... -  《-》

Hsa_circ_0023179 modulated the processes of proliferation, apoptosis, and EMT in non-small cell lung cancer cells via the miR-615-5p/CDH3 axis.

Guo Q ，Zheng M ，Zhu C ，Wu B ... -  《-》