lncRNA ZNRD1-AS1 promotes malignant lung cell proliferation, migration, and angiogenesis via the miR-942/TNS1 axis and is positively regulated by the m6A reader YTHDC2

RATIONALE

Lung cancer is the most prevalent form of cancer and has a high mortality rate, making it a global public health concern. The N⁶-methyladenosine (m⁶A) modification is a highly dynamic and reversible process that is involved in a variety of essential biological processes. Using in vitro, in vivo, and multi-omics bioinformatics, the present study aims to determine the function and regulatory mechanisms of the long non-coding (lnc)RNA zinc ribbon domain-containing 1-antisense 1 (ZNRD1-AS1).

METHODS

The RNAs that were bound to the m⁶A 'reader' were identified using YTH domain-containing 2 (YTHDC2) RNA immunoprecipitation (RIP)-sequencing. Utilizing methylated RIP PCR/quantitative PCR, pull-down, and RNA stability assays, m⁶A modification and ZNRD1-AS1 regulation were analyzed. Using bioinformatics, the expression levels and clinical significance of ZNRD1-AS1 in lung cancer were evaluated. Using fluorescent in situ hybridization and quantitative PCR assays, the subcellular location of ZNRD1-AS1 was determined. Using cell migration, proliferation, and angiogenesis assays, the biological function of ZNRD1-AS1 in lung cancer was determined. In addition, the tumor suppressor effect of ZNRD1-AS1 in vivo was validated using a xenograft animal model. Through bioinformatics analysis and in vitro assays, the downstream microRNAs (miRs) and competing endogenous RNAs were also predicted and validated.

RESULTS

This study provided evidence that m⁶A modification mediates YTHDC2-mediated downregulation of ZNRD1-AS1 in lung cancer and cigarette smoke-exposed cells. Low levels of ZNRD1-AS1 expression were linked to adverse clinicopathological characteristics, immune infiltration, and prognosis. ZNRD1-AS1 overexpression was shown to suppress lung cancer cell proliferation, migration, and angiogenesis in vitro and in vivo, and to reduce tumor growth in nude mice. ZNRD1-AS1 expression was shown to be controlled by treatment of cells with either the methylation inhibitor 3-Deazaadenosine or the demethylation inhibitor Meclofenamic. Furthermore, the miR-942/tensin 1 (TNS1) axis was demonstrated to be the downstream regulatory signaling pathway of ZNRD1-AS1.

CONCLUSIONS

ZNRD1-AS1 serves an important function and has clinical relevance in lung cancer. In addition, the findings suggested that m⁶A modification could mediate the regulation of the ZNRD1-AS1/miR-942/TNS1 axis via the m⁶A reader YTHDC2.

CircPTK2 inhibits cell cisplatin (CDDP) resistance by targeting miR-942/TRIM16 axis in non-small cell lung cancer (NSCLC)

In recent years, the problem of cancer resistance has become more and more prominent, seriously affecting treatment efficiency. Circular RNAs (circRNAs) play an important role in cell progression and cancer mechanisms. However, there is a lack of systematic studies on its function in non-small cell lung cancer (NSCLC) resistance. CircPTK2, microRNA-942 (miR-942), and Tripartite motif 16 (TRIM16) levels were detected by Real-time quantitative reverse transcriptase PCR (qRT-PCR). Extracellular acidification rate (ECAR), glucose consumption, and lactate production were assessed using the Seahorse XF96 Glycolysis Analyzer, glucose, and lactate assay kits, respectively. The protein expression was measured with the western bolt Transwell assay was used to determine migration and invasion of transfected cells. (4-5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry were applied to carry out cell proliferation and apoptosis, respectively. The relationship among circPTK2, miR-942, and TRIM16 were determined by using the dual-luciferase reporter assay and RIP assay. circPTK2 (hsa_circ_0008305) and TRIM16 were low expressed, while miR-942 was significantly highly expressed in NSCLC tissues and cell lines. Moreover, overexpression of circPTK2 remarkably inhibited cell growth, metastasis, and glycolysis in A549/CDDP and H1299/CDDP cells. Promotion of miR-942 or inhibition of TRIM16 could reverse the effects of high circPTK2 expression on cell growth, metastasis, and glycolysis in A549/CDDP and H1299/CDDP cells. CircPTK2 overexpression inhibited the growth of A549/CDDP cells in vivo. Furthermore, circPTK2 weakened CDDP resistance of NSCLC through modulating miR-942/TRIM16 axis, providing a novel sight for the treatment of NSCLC and improving the understanding of the CDDP resistance mechanism of NSCLC.

lncRNA SNHG17 promotes pancreatic carcinoma progression via cross-talking with miR-942

OBJECTIVE

Long non-coding RNA (lncRNA) SNHG17 has been shown to modulate the biological behavior of multiple cancers (e.g., colorectal and lung cancers). However, its involvement in pancreatic cancer (PC) has not been explored; therefore, in the present study, we sought to examine this involvement.

METHODS

First, the mRNA expression levels of various genes were quantified in PC tissues and cell lines using quantitative reverse-transcription PCR (qRT-PCR). The interaction between SNHG17 and miR-942 was explored by bioinformatics prediction as well as a dual luciferase reporter assay. The proliferation and viability of pancreatic carcinoma cells were examined using cell counting kit-8 and MTT assays, respectively. Cellular migratory and invasive properties were evaluated using transwell migration and wound healing assays. Cell death was measured using flow cytometry. Protein expression was quantified by western blotting.

RESULTS

SNHG17 expression was markedly higher in human PC specimens and cell lines than in normal healthy tissues and pancreatic epithelial cells. MiR-942 expression displayed the opposite trend. Bioinformatics prediction and a dual luciferase reporter assay confirmed that SNHG17 serves as a sponge for miR-942. Loss-of-function assay revealed that SNHG17 silencing reduced the proliferation and viability of PC cells, impaired their migratory and invasive capacities, and led to their apoptosis. All these changes could be reversed by miR-942 inhibition. Further mechanical studies showed that SNHG17 silencing decreased the expression of several tumor modulators, including XXX, and this decrease was countered by miR-942 inhibition.

CONCLUSION

Our study provides experimental evidence for an interaction between SNHG17 and miR-942, which may unveil a new approach for PC pharmacotherapy.

Circ_0001438 participates in the pathogenesis of preeclampsia via the circ_0001438/miR-942/NLRP3 regulatory network

INTRODUCTION

Preeclampsia (PE) is a common pregnancy disorder with multisystem complications. The growing data suggest that circular RNAs (circRNAs) involve in the development of PE. This study proposed to investigate the function and potential mechanisms of circ_0001438 in PE.

METHODS

The expression of circ_0001438, miR-942 and NOD-like receptor pyrin domain-containing protein 3 (NLRP3) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). The expression at the protein level of NLRP3, interleukin 1 beta (IL-1β), interleukin 10 (IL-10), B-cell lymphoma 2 (Bcl-2), Cleaved-caspase-3 (Cleaved-casp-3), N-cadherin and E-cadherin was detected by Western blot. Cell proliferation was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and colony formation assay. Cell apoptosis was determined by flow cytometry assay. Cell migration and invasion were monitored by transwell assay. The target genes were obtained and verified by the online bioinformatics tool and dual-luciferase reporter assay.

RESULTS

The expression of circ_0001438 and NLRP3 was enhanced in PE placenta tissues. Circ_0001438 knockdown promoted cell proliferation, migration and invasion but inhibited apoptosis and inflammatory responses in HTR-8/Svneo cells, and these effects were reversed by the inhibition of miR-942, a target of circ_0001438. Moreover, NLRP3 was bounded by miR-942. The enrichment of miR-942 accelerated cell proliferation, migration and invasion but depleted apoptosis and inflammatory responses, while these impacts were partly abolished by NLRP3 overexpression.

DISCUSSION

Circ_0001438 sponged miR-942 to regulate the expression of NLRP3, and circ_0001438 aggravated the dysfunctions of human villous trophoblasts by mediating the miR-942/NLRP3 axis at least in part.

Circular RNA hsa_circ_0001649 suppresses the growth of osteosarcoma cells via sponging multiple miRNAs

Osteosarcoma (OS) is a serious bone malignancy commonly occurred in childhood and adolescence. Circular RNA (circRNA) is a novel endogenous RNA that may be considered as a new biomarker for diseases' diagnosis or prognosis. This study explored the roles and mechanism of circ_0001649 in OS. The qRT-PCR was performed to test circ_0001649 expression in OS tissues and cells. Luciferase was used to confirm the binding of circ_0001649 with miR-338-5p, miR-647 and miR-942. OS cells were stably transfected with pEX-circ_0001649 or miRNAs mimic, CCK-8 kit, colony formation, apoptosis and western blot analysis were used to detect the roles of circ_0001649. Circ_0001649 was low-expressed in OS tissues and cell lines. Circ_0001649 overexpression suppressed U2OS and HOS cell viability and survival fraction, and induced apoptosis presented as the increasing levels of Apaf-1, cleaved-caspase-3 and cleaved-caspase-9. Further, circ_0001649 worked as a sponge to absorb miR-338-5p, miR-647 and miR-942 to suppress cell proliferation, induce apoptosis and inhibit STAT pathway. Circ_0001649 suppressed OS cell proliferation and STAT pathway and induced apoptosis through sponging miR-338-5p, miR-647 and miR-942.

miR-942 promotes proliferation and metastasis of hepatocellular carcinoma cells by inhibiting RRM2B

Background

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death. MicroRNA-942 (miR-942) plays a critical role in promoting proliferation and metastasis of cancer cells and is associated with poor prognosis in some types of cancers. However, the prognostic value of miR-942 and its functional role in HCC remain unclear.

Materials and methods

Real-time PCR (RT-PCR) was used to detect the expression of miR-942 in HCC tissues and adjacent normal liver tissues. Next, the correlations between miR-942 expression and clinicopathological parameters including the survival rate were analyzed. Interaction between miR-942 and ribonucleotide reductase regulatory TP53 inducible subunit M2B (RRM2B) was determined by RT-PCR, Western blot and luciferase assay. The biological influence of miR-942 on HCC cell lines was studied using CCK-8 assay, colony formation assay and transwell assay in vitro. Western blot and RT-PCR were used to analyze the change of downstream genes after miR-942 mimics transfection.

Results

miR-942 was significantly up-regulated in HCC. Its high expression was associated with serum alanine transaminase level (P=0.0350), tumor size (P=0.0195), T stage (P=0.0045) and lymphatic metastasis (P=0.0013). High expression of miR-942 was associated with shorter overall survival and disease-free survival time of HCC patients. RRM2B was validated as a target gene of miR-942. miR-942 mimics markedly promoted the malignant phenotypes of Huh7 and MHCC97H cell lines, while its inhibitor had the opposite effect. miR-942 can regulate the downstream genes of RRM2B including Egr-1 and PTEN, markers of epithelial-mesenchymal transition and matrix metalloproteinases.

Conclusion

miR-942 may serve as a potential biomarker for HCC and its inhibitor may be a therapeutic agent for the treatment of this deadly disease.

Circular RNA hsa_circ_0016070 Is Associated with Pulmonary Arterial Hypertension by Promoting PASMC Proliferation

Noncoding RNAs play an important role in the pathogenesis of pulmonary arterial hypertension (PAH). In this study, we investigated the roles of hsa_circ_0016070, miR-942, and CCND1 in PAH. circRNA microarray was used to search circRNAs involved in PAH, whereas real-time PCR and western blot analysis were performed to detect miR-942 and CCND1 expression in different groups. In addition, the effect of miR-942 on CCND1 expression, as well as the effect of hsa_circ_0016070 on the expression of miR-942 and CCND1, was also studied using real-time PCR and western blot analysis. Moreover, MTT assay and flow cytometry were used to detect the effect of hsa _circ_0016070 on cell proliferation and cell cycle. According to the results of circRNA microarray analysis, hsa _circ_0016070 was identified to be associated with the risk of PAH in chronic obstructive pulmonary disease (COPD) patients. The miR-942 level in the COPD(+) PAH(+) group was much lower than that in the COPD(+) PAH(−) group, while the CCND1 level in the COPD(+) PAH(+) group was much higher. CCND1 was identified as a candidate target gene of miR-942, and the luciferase assay showed that the luciferase activity of wild-type CCND1 3′ UTR was inhibited by miR-942 mimics. In addition, hsa _circ_0016070 reduced miR-942 expression and enhanced CCND1 expression. Furthermore, hsa _circ_0016070 evidently increased cell viability and decreased the number of cells arrested in the G1/G0 phase. In summary, the results of this study suggested that hsa_circ_0016070 was associated with vascular remodeling in PAH by promoting the proliferation of pulmonary artery smooth muscle cells (PASMCs) via the miR-942/CCND1. Accordingly, has_circ_0016070 might be used as a novel biomarker in the diagnosis and treatment of PAH.

miR-942 promotes tumor migration, invasion, and angiogenesis by regulating EMT via BARX2 in non-small-cell lung cancer

Epithelial-mesenchymal transition (EMT) has an important function in cancer. Recently, microRNAs have been reported to be involved in EMT by regulating target genes. miR-942 is considered a novel oncogene in esophageal squamous cell carcinoma. However, its role in non-small-cell lung cancer (NSCLC) has not been investigated. In this study, the expression of miR-942 in NSCLC patients tumor and paired adjacent tissues were assessed by quantitative real-time polymerase chain reaction and in situ hybridization. Transwell, wound healing, tube formation, and tail vein xenograft assays were conducted to assess miR-942's function in NSCLC. Potential miR-942 targets were confirmed using dual-luciferase reporter assays, immunohistochemistry, immunoblot, and rescue experiments. The results showed miR-942 is relatively highly expressed in human NSCLC tissues and cells. In vitro assays demonstrated that overexpression of miR-942 promoted cell migration, invasion, and angiogenesis. Tail vein xenograft assays suggested that miR-942 contributed to NSCLC metastasis in vivo. Three bioinformatics software was searched, and BARX2 was predicted as a downstream target of miR-942. Direct interaction between them was validated by dual-luciferase assays. Rescue experiments further confirmed that BARX2 overexpression could reverse functional changes caused by miR-942. Moreover, miR-942 increased EMT-associated proteins N-cadherin and vimentin by inhibiting BARX2, while E-cadherin expression is reduced. In summary, this study reveals that miR-942 induces EMT-related metastasis by directly targeting BARX2, which may provide a potential therapeutic strategy for NSCLC.

circEPSTI1 regulates ovarian cancer progression via decoying miR-942

Increasing studies show that circular RNAs (circRNAs) play vital roles in tumour progression. But, how circRNAs function in ovarian cancer is mostly unclear. Here, we detected the expression of circEPSTI1 in ovarian cancer and explored the function of circEPSTI1 in ovarian cancer via a series of experiments. Then, we performed luciferase assay and RNA immunoprecipitation (RIP) assay to explore the competing endogenous RNA (ceRNA) function of circEPSTI1 in ovarian cancer. qRT-PCR verified that circEPSTI1 was overexpressed in ovarian cancer. Inhibition of circEPSTI1 suppressed ovarian cancer cell proliferation, invasion but promoted cell apoptosis. Luciferase assays and RIP assay showed that circEPSTI1 and EPSTI1 (epithelial stromal interaction 1) could directly bind to miR-942. And circEPSTI1 could regulate EPSTI1 expression via sponging miR-942. In summary, circEPSTI1 regulated EPSTI1 expression and ovarian cancer progression by sponging miR-942. circEPSTI1 could be used as a biomarker and therapeutic target in ovarian cancer.

MiR-942 decreased before 20 weeks gestation in women with preeclampsia and was associated with the pathophysiology of preeclampsia in vitro

OBJECTIVE

To investigate the possible relationship between miR-942 levels and the pathogenesis of preeclampsia using in vitro assays and to investigate circulating miR-942 levels in the early phase of mid-of pregnancy in women who later developed preeclampsia and in women with uncomplicated pregnancies.

METHODS

Plasma samples were collected from pregnant women between 12 and 20 weeks of gestation. MiR-942 levels were determined by stem-loop real-time PCR for 26 cases who subsequently developed preeclampsia as well as for 52 controls. Bioinformatics software was used to predict the target genes of miR-942, and a dual-luciferase reporter system was utilized to validate target gene regulation. Finally, MTT proliferation assays, transwell invasion assays, and endothelial cell tube formation assays were performed to further explore the function of miR-942 using a human extravillous trophoblast cell line (TEV-1).

RESULT

Circulating miR-942 levels were significantly lower in mid-pregnancy (12-20 weeks gestation) in women who later developed preeclampsia compared with those with an uncomplicated pregnancy (p < 0.05). Endoglin (ENG) is an miR-942 target gene. MiR-942 had a sensitivity of 0.673, a specificity of 0.875, and an area under the receiver operating characteristic curve (AUC) of 0.718 [95% CI, 0.594-0.822] for the possible screening of preeclampsia. In vitro, decreased miR-942 expression decreased the invasive ability of TEV-1 cells, and inhibited the HUVEC angiogenesis assay, both effects that are similar to what is observed in preeclampsia (both p <0.05).

CONCLUSION

MiR-942 may be involved in the pathogenesis of preeclampsia via the regulation of its target gene ENG. Multicenter studies must be performed and a greater number of samples must be analyzed to ascertain whether circulating miR-942 levels can serve as a novel early diagnostic marker for preeclampsia.

miR-942 promotes cancer stem cell-like traits in esophageal squamous cell carcinoma through activation of Wnt/β-catenin signalling pathway

The Wnt/β-catenin signalling pathway is known to play a vital role in the maintenance of cancer stem cells (CSCs), which are reported to be the origine of malignant cancers, and result in poor prognosis of multiple kinds of cancer. Therefore, it is of great importance to illuminate the mechanism by which the Wnt/β-catenin pathway regulates the cancer stem cell-like traits in cancers. Here, we report that miR-942 is significantly upregulated in esophageal squamous cell carcinoma (ESCC), and miR-942 levels are associated with poor prognosis in ESCC patients. Overexpression of miR-942 promotes, whereas inhibition of miR-942 decreases, the tumor sphere formation, the CD90⁺ subpopulation cells and the expression of pluripotency associated markers. Moreover, in vivo assay shows that miR-942 overexpressing cells form larger tumors and display higher tumourigenesis. Furthermore, we demonstrate that miR-942 upregulates the Wnt/β-catenin signaling activity via directly targeting sFRP4, GSK3β and TLE1, which are multiple level negative regulators of the Wnt/β-catenin signaling cascade. In addition, our results indicate that c-myc directly binds to the miR-942 promoter and promotes its expression. Taken together, our findings establish an oncogenic role of miR-942 in ESCC and indicate that miR-942 might be an effective therapeutic target for ESCC.