Circular RNA circABCC4 regulates lung adenocarcinoma progression via miR-3186-3p/TNRC6B axis

Lung adenocarcinoma (LUAD), a general kind of bronchogenic malignancy globally, is depicted as one of the most critical factors affecting human health severely. Featured with loop structure, circular RNA (circRNA) has been described as an essential regulator of multiple human malignancies. Nevertheless, knowledge concerning the regulatory function of circRNA in LUAD progression remains limited. Identified as a novel circRNA, circABCC4 has not been studied in LUAD as yet. This is the first time to probe into the underlying role of circABCC4 in LUAD. In this study, a notably elevated expression of circABCC4 was found in LUAD tissues and cells. Besides, circABCC4 is verified to be characterized with a circular structure in LUAD. Functional assays elucidated that knockdown of circABCC4 significantly impaired LUAD cell proliferation, migration as well as accelerated cell apoptosis. Molecular mechanism experiments later revealed that circABCC4 could bind with miR-3186-3p and miR-3186-3p was a tumor suppressor in LUAD. Moreover, TNRC6B was validated to combine with miR-3186-3p, and its expression was respectively negatively and positively regulated by miR-3186-3p and circABCC4 in LUAD. Final rescue experiments further delineated that TNRC6B upregulation partially restored circABCC4 downregulation-mediated effect on LUAD progression. In sum, circABCC4 regulates LUAD progression via miR-3186-3p/TNRC6B axis.     

Long noncoding RNA FLVCR1-AS1 aggravates biological behaviors of glioma cells via targeting miR-4731-5p/E2F2 axis

Long noncoding RNAs (lncRNAs) display essential roles in cancer progression. FLVCR1-AS1 is a rarely investigated lncRNAs involved in various human cancers, such as hepatocellular carcinoma and lung cancer. However, its function in glioma has not been clarified. In our study, we found that FLVCR1-AS1 was highly expressed in glioma tissues and cell lines. And upregulation of FLVCR1-AS1 predicted poor prognosis in patients with glioma. Moreover, FLVCR1-AS1 knockdown inhibited proliferation, migration and invasion of glioma cells. Through bioinformatics analysis, we identified that FLVCR1-AS1 was a sponge for miR-4731-5p to upregulate E2F2 expression. Moreover, rescue assays indicated that FLVCR1-AS1 modulated E2F2 expression to participate in glioma progression. Altogether, our research demonstrates that the FLVCR1-AS1/miR-4731-5p/E2F2 axis is a novel signaling in glioma and may be a potential target for tumor therapy.     

TGFβ mediated LINC00273 upregulation sponges mir200a-3p and promotes invasion and metastasis by activating ZEB1

Transforming growth factor β (TGFβ) is a prominent cytokine that promotes tumor progression by activating epithelial-to-mesenchymal transition (EMT). This study indicated that TGFβ exerted metastasis by inducing zinc finger E-box binding homeobox 1 (ZEB1) and a long noncoding RNA, LINC00273, expressions in A549 cells. Knocking down LINC00273 diminished TGFβ induced ZEB1 expression as well as metastasis. Mechanistically, LINC00273 acted as a molecular sponge of microRNA (miR)-200a-3p which liberate ZEB1 to perform its prometastatic functions. LINC00273 knockdown and miR200a3p mimic transfection of A549 cells were used for validating the link between TGFβ and LINC00273 induced metastasis. RNA pulldown and luciferase assay were performed to establish mir200a-3p-LINC00273 interaction. High expressions of LINC00273, TGFβ, and ZEB1 with concurrent low miR200a-3p expression had been verified in vivo and in patient samples. Overall, LINC00273 promoted TGFβ-induced lung cancer EMT through miR-200a-3p/ZEB1 feedback loop and may serve as a potential target for therapeutic intervention in lung cancer metastasis.     

Deregulation of UCA1 expression may be involved in the development of chemoresistance to cisplatin in the treatment of non-small-cell lung cancer via regulating the signaling pathway of microRNA-495/NRF2

Non-small-cell lung cancer (NSCLC) remains the leading cause of cancer death worldwide. As a platinum-based chemotherapeutic drug, cisplatin has been used for over 30 years in NSCLC treatment while its effects are diminished by drug resistance. Therefore, we aimed to study the potential role of UCA1 in the development of chemoresistance against cisplatin. Real-time polymerase chain reaction, western-blot analysis, and immunofluorescence were used to study the involvement of UCA1, miR-495, and NRF2 in chemoresistance against cisplatin. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to determine the effect of cisplatin on cell proliferation. Computational analysis and luciferase assay were carried out to explore the interaction among UCA1, miR-495, and NRF2. The cisplatin-R group exhibited lower levels of UCA1 and NRF2 expression but a higher level of miR-495 expression than the cisplatin-S group. The growth rate and half-maximal inhibitory concentration of cellular dipeptidyl peptidase (cisplatinum) of the cisplatin-R group were much higher than those in the cisplatin-S group. MiR-495 contained a complementary binding site of UCA1, and the luciferase activity of wild-type UCA1 was significantly reduced after the transfection of miR-495 mimics. MiR-495 directly targeted the 3′-untranslated region (3′-UTR) of NRF2, and the luciferase activity of wild-type NRF2 3′-UTR was evidently inhibited by miR-495 mimics. Finally, UCA1 and NRF2 expressions in the effective group were much lower than that in the ineffective group, along with a much higher level of miR-495 expression. We suggested for the first time that high expression of UCA1 contributed to the development of chemoresistance to cisplatin through the UCA1/miR-495/NRF2 signaling pathway.     

Long noncoding RNA LINC00319 regulates ROMO1 expression and promotes bladder cancer progression via miR-4492/ROMO1 axis

Growing reports indicate that long noncoding RNA (lncRNA) are involved in the regulation of various biological processes of cancer cells. LINC00319 is an ill investigated lncRNA and has been shown to regulate lung cancer, nasopharyngeal carcinoma and ovarian cancer. Nevertheless, its roles in bladder cancer (BCa) remain unclear. In our research, LINC00319 was shown to be an upregulated lncRNA in BCa tissues. LINC00319 expression is negatively correlated with the patient's prognosis. Silencing of LINC00319 suppressed BCa proliferation and invasiveness. In addition, the data indicated LINC00319 was a sponge for miR-4492 and miR-4492 suppressed ROMO1 expression in BCa. Furthermore, our results illustrated miR-4492/ROMO1 axis regulates proliferation, migration, and invasion and LINC00319 exerts oncogenic roles through modulating miR-4492/ROMO1 axis. In sum, this study suggested that LINC00319 acts as oncogenic roles in BCa progression.     

miR-122-5p promotes aggression and epithelial-mesenchymal transition in triple-negative breast cancer by suppressing charged multivesicular body protein 3 through mitogen-activated protein kinase signaling

Triple-negative breast cancer (TNBC) is highly metastatic and frequently has a poor prognosis. The lack of comprehension of TNBC and gene therapy targets has led to limitedly effective treatment for TNBC. This study was conducted to better understand the molecular mechanism behind TNBC progression, and to find out promising gene therapy targets for TNBC. Herein the influence of miR-122-5p's binding charged multivesicular body protein 3 (CHMP3) 3′-untranslated region (3′-UTR) on in TNBC cells was investigated. in vitro experiments quantitative real-time polymerase chain reaction, immunoblot analysis, dual-luciferase reporter gene assay, cell counting assay, transwell invasion assay, and flow cytometry-determined cell apoptosis assay were employed. We also used TargetScan Human 7.2 database to find out the target relationship between miR-122-5p and CHMP3 3′-UTR. TImer algorithm was used to provide an overview of the expression of CHMP3 gene across human pan-cancer, to predict the survival outcome of breast cancer patients, and to predict the correlation between CHMP3 gene expression and epithelial-mesenchymal transition (EMT) and mitogen-activated protein kinase (MAPK)-related gene expression. CHMP3 gene was significantly downregulated across a wide range of human cancers including breast cancer (BRCA). A higher level of CHMP3 gene predicted a better 3- and 5-year survival outcome of patients with BRCA. In our experiments, miR-122-5p was significantly upregulated and CHMP3 gene was significantly downregulated in TNBC cells compared with normal cell line. miR-122-5p mimics enhanced TNBC cell viability, proliferation, and invasion whereas the upregulation of CHMP3 gene led to an opposite outcome. Forced expression of miR-122-5p suppressed cell apoptosis, compelled EMT and MAPK signaling whereas forced expression of CHMP3 did the opposite. We then conclude that miR-122-5p promotes aggression and EMT in TNBC by suppressing CHMP3 through MAPK signaling.     

LINC00205 modulates the expression of EPHX1 through the inhibition of miR-184 in hepatocellular carcinoma as a ceRNA

Several studies have shown that low expression of epoxide hydrolase 1 (EPHX1) is closely associated with varying human cancers, including hepatocellular carcinoma (HCC). This study aims to explore the potential mechanism of EPHX1 silencing and revealed a novel regulatory pathway in the pathogenesis of HCC. In this study, micro ribonucleic acid (miR)-184 was predicted and validated to be a regulator of EPHX1 through experiments, and its expression was negatively correlated with the messenger RNA (mRNA) levels of EPHX1 in primary tumors. Elevation of EPHX1 suppressed cell proliferation and migration as well as cell cycle progression, and induced apoptosis, while downregulation of miR-184 exhibited the opposite effect on cellular processes. Moreover, LINC00205 interacted with miR-184 and was markedly downregulated in tumors. The effects of the miR-184 inhibitor on cell proliferation, apoptosis, and migration were reversed in part by the transfection with LINC00205 small interfering RNAs. In addition, LINC00205 acted as a molecular sponge to positively regulate the mRNA and protein levels of EPHX1 via regulating miR-184. The tumorigenicity of HCC cells was enhanced by LINC00205 shRNA but diminished by overexpression of EPHX1 in vivo. Clinically, the EPHX1 expression in patients with HCC was markedly downregulated. Taken together, the results of this study suggest that as a competing endogenous RNA, LINC00205 may regulate EPHX1 by inhibiting miR-184 in the progression of HCC and that targeting the LINC00205/miR-184/EPHX1 axis may provide a treatment protocol for patients.