Linc-ROR regulates apoptosis in esophageal squamous cell carcinoma via modulation of p53 ubiquitination by targeting miR-204-5p/MDM2

The long intergenic noncoding RNA, regulator of reprogramming (linc-ROR) has been reported to participate in tumorigenesis, while its functions and fundamental mechanisms in esophageal squamous cell carcinoma (ESCC) remain unclear. In this study, gain-of-function assays showed that linc-ROR upregulation enhanced cell viability, promoted cell proliferation, and inhibited apoptosis. Mechanistically, the regulatory network of linc-ROR/miR-204-5p/MDM2 was established with bioinformatics analysis and online databases, then validated via dual-luciferase reporter assays, RNA immunoprecipitation assays in ESCC cells. Linc-ROR positively regulates the expression of MDM2 as a molecular sponge of miR-204-5p. Moreover, results of western blot and coimmunoprecipitation indicated that linc-ROR overexpression enhanced the ubiquitination level of p53, and its downstream apoptosis-related genes have showed higher bcl-2 expression, lower bax, and cleaved caspase-3 expressions, while miR-204-5p could counteract with this effect. Finally, small interfering RNAs tailored to linc-ROR were established to further evaluate its effects on ESCC comprehensively. In summary, this study revealed that linc-ROR modulated cell apoptosis and regulated p53 ubiquitination via targeting miR-204-5p/MDM2 axis, which provides a novel therapeutic insight into treatments for ESCC.     

Up-regulated miR-548k promotes esophageal squamous cell carcinoma progression via targeting long noncoding RNA-LET

Dysregulated noncoding RNAs have been observed in diverse cancers. MIR458K is frequently amplified in esophageal squamous cell carcinoma (ESCC). However, the expression, clinical significances, and action mechanisms of miR-548k in ESCC are still unclear. In this study, we found that miR-548k is significantly up-regulated in ESCC tissues and cell lines. Up-regulated miR-548k expression is significantly correlated with advanced invasion depth, lymph node metastasis, advanced TNM stage, and poor overall survival. Gain-of- and loss-of-function assays demonstrated that miR-548k promotes the proliferation and migration of ESCC cells in vitro and tumor growth in vivo. Mechanistically, we found that miR-548k directly targets and represses the expression of long noncoding RNA-LET (lncRNA-LET), and further down-regulates p53 and up-regulates NF90. In addition, we found that lncRNA-LET is down-regulated and inversely correlated with miR-548k in ESCC. Down-regulated lncRNA-LET also indicated poor overall survival of ESCC patients. Functional assays demonstrated that lncRNA-LET inhibits the proliferation and migration of ESCC cells, and the effects of miR-548k on ESCC are dependent on the negative regulation of lncRNA-LET. In summary, our data revealed the critical roles of miR-548k-lncRNA-LET regulation axis in ESCC and suggested that the miR-548k-lncRNA-LET regulation axis may be promising prognostic biomarkers and therapeutic targets for ESCC.     

Tumor-Suppressive Function of miR-139-5p in Esophageal Squamous Cell Carcinoma

Recent studies have demonstrated the possible function of miR-139-5p in tumorigenesis. However, the exact mechanism of miR-139-5p in cancer remains unclear. In this study, the association of miR-139-5p expression with esophageal squamous cell carcinoma (ESCC) was evaluated in 106 pairs of esophageal cancer and adjacent non-cancerous tissue from ESCC patients. The tumor suppressive features of miR-139-5p were measured by evaluating cell proliferation and cell cycle state, migratory activity and invasion capability, as well as apoptosis. Luciferase reporter assay and Western blot analysis were performed to determine the target gene regulated by miR-139-5p. The mRNA level of NR5A2, the target gene of miR-139-5p, was determined in ESCC patients. Results showed that reduced miR-139-5p level was associated with lymph node metastases of ESCC. MiR-139-5p was investigated to induce cell cycle arrest in the G0/G1 phase and to suppress the invasive capability of esophageal carcinoma cells by targeting the 3′UTR of oncogenic NR5A2. Cyclin E1 and MMP9 were confirmed to participate in cell cycle arrest and invasive suppression induced by NR5A2, respectively. Pearson correlation analysis further confirmed the significantly negative correlation between miR-139-5p and NR5A2 expression. The results suggest that miR-139-5p exerts a growth- and invasiveness-suppressing function in human ESCCs, which demonstrates that miR-139-5p is a potential biomarker for early diagnosis and prognosis and is a therapeutic target for ESCC.     

miR-204-5p regulates cell proliferation,invasion, and apoptosis by targeting IL-11 in esophageal squamous cell carcinoma

Esophageal cancer (EC) is the world's eighth most common malignant neoplasm and is ranked as the sixth leading cause of death related to cancer. Aberrant microRNA (miRNA) expression has been reported to be associated with esophageal squamous cell carcinoma. However, the molecular mechanism of miR-204-5p in esophageal squamous cell carcinoma (ESCC) is not clear. Therefore, the aim of this study was to investigate the potential role of miR-204-5p in ESCC. In the present study, we found that miR-204-5p could affect ESCC proliferation, invasion, apoptosis, and cell cycle in cell and mouse models. A dual-luciferase reporter assay showed that miR-204-5p expression was negatively correlated with interleukin-11 (IL-11) expression. IL-11 overexpression reversed the suppressive effects of miR-204-5p in the cell lines. These results indicated that miR-204-5p functions as a tumor suppressor by directly targeting IL-11 in ESCC.     

MiR-4282 inhibits tumor progression through down-regulation of ZBTB2 by targeting LIN28B in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most aggressive type of head and neck cancer with an unsatisfactory 5-year survival rate. MicroRNAs are a group of small noncoding RNAs reported to serve important roles in carcinogenesis, inhibiting certain gene expression via targeting the 3′-untranslated region of messenger RNAs (mRNAs). MiR-4282 has been newly discovered to be a tumor suppressor in colorectal cancer, but it has never been studied in OSCC. The present study aimed to uncover the role of miR-4282 in OSCC. We first confirmed that miR-4282 was downregulated in OSCC and validated its prognostic significance. Through gain-of-function assays, miR-4282 was discovered to inhibit proliferation, migration, and epithelial-to-mesenchymal transition, and induce apoptosis. By mechanistic research, we predicted via bioinformatics tools and confirmed by luciferase reporter and pulldown assays that miR-4282 targeted LIN28B, an RNA-binding protein, which has been reported to regulate RNA stability in cancers. Furthermore, we confirmed the interaction between LIN28B and zinc finger and BTB domain containing 2 (ZBTB2), and validated that miR-4282 regulated mRNA stability of ZBTB2 by inhibiting LIN28B. Rescue assays proved that miR-4282 inhibited tumor progression through LIN28B/ZBTB2 axis. In vivo assays proved that miR-4282 inhibited tumor growth in OSCC. In conclusion, the present study revealed that miR-4282 inhibited tumor progression through downregulation of ZBTB2 by targeting LIN28B in OSCC cells, indicating miR-4282 as a novel biomarker for OSC.     

Tumor-suppressive microRNA-10a inhibits cell proliferation and metastasis by targeting Tiam1 in esophageal squamous cell carcinoma

Aberrant microRNAs (miRNAs) expressions could contribute to the progression of numerous cancers, including esophageal squamous cell carcinoma, while miR-10a participates in multiple biological processes on cancers. However, the molecular mechanism of miR-10a in esophageal squamous cell carcinoma (ESCC) has not been investigated. Herein, miR-10a was significantly reduced in ESCC clinical tissues and ESCC cell lines (EC109 and TE-3). In addition, immunohistochemistry indicated that the expressions of α-SMA, Ki-67, and PCNA in tumor tissues were higher than that of controls. In vitro, overexpression of miR-10a dramatically suppressed cell proliferation and enhanced cell apoptosis, while the decrease of miR-10a expressed the opposite outcome. Specially, overexpression of miR-10a caused a G0/G1 peak accumulation. Moreover, miR-10a also negatively regulated ESCC cell migration and invasion. Furthermore, targetscan bioinformatics predictions and the dual-luciferase assay confirmed that Tiam1 was a direct target gene of miR-10a. The statistical analysis showed Tiam1 was negatively in correlation with miR-10a in ESCC patient samples. And silencing Tiam1 could lead to a decline on cell growth, invasion, and migration in ESCC cell lines, while it could enhance cell apoptosis and cause a G0/G1 peak accumulation. In vivo, it revealed that miR-10a notably decreased the tumor growth and metastasis in xenograft model and pulmonary metastasis model. And it showed a lower expressions of Tiam1 in the miR-10a mimics group by immunohistochemistry. Taken together the results, they indicated that miR-10a might function as a novel tumor suppressor in vitro and in vivo via targeting Tiam1, suggesting miR-10a to be a candidate biomarker for the ESCC therapy.     

microRNA-485-5p inhibits the progression of hepatocellular carcinoma through blocking the WBP2/Wnt signaling pathway

microRNA-485-5p (miR-485-5p) has been shown to act as a tumor-suppressor gene in some cancers, such as ovarian epithelial tumors and oral tongue squamous cell carcinoma. However, with regard to the anti-tumor role of miR-485-5p in hepatocellular carcinoma (HCC), evidence is unexpectedly limited. In the present study, we investigated the expression and the role of miR-485-5p in the progression of HCC. Microarray analysis revealed that miR-485-5p was downregulated and WBP2 was upregulated in HCC, which was consistent with RT-qPCR and immunohistochemistry assays in the HCC tissues we collected. A negative correlation between the expression of miR-485-5p and WBP2 was also found in HCC tissues. It was predicted and confirmed that miR-485-5p could bind to WW domain binding protein 2 (WBP2) through in silico analysis of genetic sequences and an in vitro dual-luciferase reporter gene assay. Next, gain- or loss-of-function studies were applied in the HCC cell line (Huh7) to examine the effects of miR-485-5p and WBP2 on HCC cell behavior. The effects of miR-485-5p and WBP2 on the Wnt/β-catenin signaling pathway were determined by TOP/FOP flash luciferase assays. miR-485-5p was shown to downregulate WBP2 and block the Wnt/β-catenin signaling pathway. As expected, elevated miR-485-5p levels and inhibition of WBP2 protein expression exerted inhibitory effects on HCC cell proliferation, migration and invasion and, induced apoptosis. In vivo experiments were finally conducted, which confirmed that upregulation of miR-485-5p or depletion of WBP2 attenuated tumor growth. Collectively, our results suggest miR-485-5p can downregulate WBP2 to inhibit the development of HCC by the blockade of the Wnt/β-catenin signaling, providing a novel molecular target for HCC treatment.     

MicroRNA-21 promotes the proliferation and inhibits apoptosis in Eca109 via activating ERK1/2/MAPK pathway

The aim of this study was to investigate how miR-21 promotes proliferation and inhibits apoptosis in esophageal squamous cell carcinoma (ESCC). MTT, wound healing assay and cell cycle showed that proliferation and migration of ESCC cell line Eca109 cells were increased in miR-21 mimics group, and decreased in anti-miR-21 Oligonucleotide (AMO) group after transfection into Eca109 cells with miR-21 mimics, AMO and scramble sequence, respectively. Cell apoptosis assay indicated that cell apoptosis can be obviously inhibited by overexpression of miR-21 and promoted by downregulation of miR-21. Meanwhile, western-blot results showed that p-ERK1/2 expression was elevated in miR-21 mimics group, whereas decreased in AMO group. Furthermore, the ERK1/2, a key component of MAPK signaling pathway, was knocked down, and overexpressed successfully using shRNA-ERK1/2 and overexpressing plasmids containing full length cDNA of ERK1/2, respectively. It was observed that shRNA-ERK1/2 can significantly decreased the level of miR-21 expression, while overexpression of ERK1/2 can up-regulate expression of miR-21. As further confirmation, Eca109 cells were treated with gradient concentration of U0126, a kind of MEK inhibitor, and expression of miR-21 was subsequently examined. It was found that U0126 can significantly decreased endogenous expression of miR-21. In parallel, U0126 decreased cell proliferation, migration and increased the apoptosis in Eca109 cells, with the expression of miR-21 being reduced significantly in U0126 group as compared with control groups. Our findings indicated that miR-21 promoted the proliferation, migration and inhibited apoptosis of Eca109 cells through activating ERK1/2/MAPK pathway, and that targeting miR-21 could be a promising therapeutic strategy in ESCC.     

Long noncoding RNA lnc-ABCA12-3 promotes cell migration,invasion, and proliferation by regulating fibronectin 1 in esophageal squamous cell carcinoma

Long noncoding RNAs (lncRNAs) have been shown to play important roles in human cancers, including esophageal squamous cell carcinoma (ESCC). We previously demonstrated that a novel lncRNA, lnc-ABCA12-3, was overexpressed in ESCC tissues. However, the exact function of lnc-ABCA12-3 is unknown. In the current study, we aimed to evaluate the expression of lnc-ABCA12-3 in ESCC and to explore the potential mechanism of lnc-ABCA12-3 in cell migration, invasion, and proliferation. We showed that lnc-ABCA12-3 was upregulated in ESCC tumor tissues and cell lines. The increased expression of lnc-ABCA12-3 was positively associated with advanced tumor-node-metastasis stages and poor prognosis. The knockdown of lnc-ABCA12-3 inhibited the cell migration, invasion, and proliferation abilities of KYSE-510 and Eca-109 cells. We also found that fibronectin 1 (FN1) was upregulated in ESCC tumor tissues. The expression of FN1 messenger RNA was positively correlated with the expression of lnc-ABCA12-3 in ESCC tumor tissues. After lnc-ABCA12-3 knockdown, the expression of FN1 was downregulated. In addition, the overexpression of FN1 restored the abilities of cell migration, invasion and proliferation in Eca-109 cells. Further studies indicated that lnc-ABCA12-3 acted as a competing endogenous RNA for miR-200b-3p to regulate FN1 expression. In conclusion, these results suggest that lnc-ABCA12-3 is a novel oncogene in tumorigenesis and that its high expression is related to a poor prognosis for patients with ESCC. lnc-ABCA12-3 promotes cell migration, invasion, and proliferation via the regulation of FN1 in ESCC. Our data suggest that lnc-ABCA12-3 might serve as a potential prognostic biomarker and therapeutic target for ESCC.     

Restoration of circPSMC3 sensitizes gefitinib-resistant esophageal squamous cell carcinoma cells to gefitinib by regulating miR-10a-5p/PTEN axis

Circular RNAs (circRNAs) has been shown to play an important role in the progression of various cancers. However, the function and underlying mechanisms of circRNAs affecting chemotherapy resistance in esophageal squamous cell carcinoma (ESCC) remain largely unknown. In this study, we used gefitinib-resistant (GR) ESCC cells to investigate the function of circPSMC3 and clarify the underlying mechanism in chemotherapy resistance in ESCC. The results suggested that circPSMC3 expression was downregulated, but miR-10a-5p was upregulated in ESCC tissues and cells, as well as in GR ESCC cells. CircPSMC3 overexpression increased the sensitivity of ESCC cells to gefitinib, as indicated by reduced half maximal inhibitory concentration value, increased apoptosis rate and cleaved caspase-3 protein expression. CircPSMC3 directly interacted with miR-10a-5p and inhibited the expression of miR-10a-5p. Phosphatase and tensin homolog (PTEN) was a direct target of miR-10a-5p and circPSMC3 promoted PTEN expression via decreasing miR-10a-5p level. Moreover, the effect of circPSMC3 on resistance of GR ESCC cells to gefitinib was remarkably reduced by restoration of miR-10a-5p and downregultion of PTEN. Taken together, these observations suggested that upregulation of circPSMC3 overcame resistance of GR ESCC cells to gefitinib by modulating the miR-10a-5p/PTEN axis, which provide a new therapeutic strategy for overcoming gefitinib resistance in ESCC.     

Circ_0004712 promotes endometriotic epithelial cell proliferation,migration and invasion by regulating miR-488-3p/ROCK1 axis in vitro

Recent evidence indicates that circular RNAs (circRNAs) play crucial regulatory roles in the pathogenesis and development of endometriosis. Circ_0004712 was found to be differentially expressed in endometriosis. However, the detailed function and mechanism of circ_0004712 in endometriosis are still unclear. Quantitative real-time polymerase chain reaction and Western blot were used for the detection of circ_0004712, miR-488-3p and ROCK1 (Rho Associated Coiled-Coil Containing Protein Kinase 1) levels. In vitro experiments in endometrial endothelial cells were performed by cell counting kit-8, EdU, transwell, wound healing assays, and flow cytometry, respectively. The molecular mechanism of circ_0004712 function was investigated using bioinformatics target predication, dual-luciferase reporter, and RNA immunoprecipitation (RIP) assays. The expression of circ_0004712 was higher in endometriotic endometrial tissues and epithelial cells. Knockdown of circ_0004712 suppressed cell proliferation, migration, invasion, EMT process and induced apoptosis in ectopic endometrial epithelial cells in vitro. Mechanistically, circ_0004712 acted as a ceRNA to sponge miR-488-3p, thus elevating the expression of ROCK1, which was confirmed to be a target of miR-488-3p. Rescue experiments suggested that miR-488-3p inhibition reversed the inhibitory effects of circ_0004712 silencing on cell growth and metastasis. Moreover, miR-488-3p restoration restrained the proliferation and metastasis in ectopic endometrial epithelial cells, which were attenuated by ROCK1 overexpression. Circ_0004712 knockdown suppressed the proliferation and metastasis of ectopic endometrial epithelial cells via miR-488-3p/ROCK1 axis in vitro, suggesting a new insight into the pathogenesis of endometriosis.     

p53/miR-30a-5p/ SOX4 feedback loop mediates cellular proliferation,apoptosis, and migration of non-small-cell lung cancer

Many microRNAs (miRNAs) play vital roles in the tumorigenesis and development of cancers. In this study, we aimed to identify the differentially expressed miRNAs and their specific mechanisms in non-small-cell lung cancer (NSCLC). Based on data from the GSE56036 database, miR-30a-5p expression was identified to be downregulated in NSCLC. Further investigations showed that overexpression of miR-30a-5p inhibited cell proliferation, migration, and promoted apoptosis in NSCLC. Increase of miR-30a-5p level could induce the increase of Bax protein level and decrease of Bcl-2 protein level. In addition, chromatin immunoprecipitation assays showed that miR-30a-5p expression was induced by binding of p53 to the promoter of MIR30A. Bioinformatics prediction indicated that miR-30a-5p targets SOX4, and western blot analysis indicated that overexpression of the miRNA decreases the SOX4 protein expression level, which in turn regulated the level of p53. Thus, this study provides evidence for the existence of a p53/miR-30a-5p/SOX4 feedback loop, which likely plays a key role in the regulation of proliferation, apoptosis, and migration in NSCLC, highlighting a new therapeutic target.