MiR-215, an activator of the CTNNBIP1/β-catenin pathway,is a marker of poor prognosis in human glioma

MicroRNA-215 (miR-215) promotes tumor growth in various human malignancies. However, its role has not yet been determined in human glioma. Here, we found that levels of miR-215 were higher in glioma tissues than in corresponding non-neoplastic brain tissue. High miR-215 expression was correlated with higher World Health Organization (WHO) grades and shorter overall survival. Multivariate and univariate analysis indicated that miR-215 expression was an independent prognostic factor. We also found that TGF-beta1, phosphorylated beta-catenin, alpha-SMA, and fibronectin were increased in glioma tissues. Additionally, CTNNBIP1, a direct target of miR-215, was decreased in glioma compared to adjacent normal tissue. These data indicate that miR-215 activates Wnt/β-catenin signaling by increasing β-catenin phosphorylation, α-SMA expression, and fibronectin expression. It promotes TGF-β1-induced oncogenesis by suppressing CTNNBIP1 in glioma. In summary, miR-215 is overexpressed in human glioma, is involved in TGF-β1-induced oncogenesis, and can be used as a marker of poor prognosis in glioma patients.     

circTOP2A functions as a ceRNA to promote glioma progression by upregulating RPN2

Competing endogenous RNA (ceRNA)-mediated signaling pathway dysregulation provides great insight into comprehensively understanding the molecular mechanism and combined targeted therapy for glioblastoma. circRNA is characterized by high stability, tissue/developmental stage-specific expression and abundance in brain and plays significant roles in the initiation and progression of cancer. Our previous published data have demonstrated that RPN2 was significantly upregulated in glioma and promoted tumor progression via the activation of the Wnt/β-catenin pathway. Furthermore, we proved that miR-422a regulated the Wnt/β-catenin signaling pathway by directly targeting RPN2. In this study, based on the glioblastoma microarray profiles, we identified the upstream circTOP2A, which completely bound to miR-422a and was co-expressed with the RPN2. circTOP2A was significantly overexpressed in glioma and conferred a poor prognosis. circTOP2A could regulate RPN2 expression by sponging miR-422a, verified by western blot, dual-luciferase reporter gene assay, and RNA pull-down assay. Functional assays including CCK8, transwell and FITC-annexin V were performed to explore the RPN2-mediated role of the circTOP2A effect on the glioma malignant phenotype. Additionally, TOP/FOP and immunofluorescence analysis were used to confirm that sh-circTOP2A could suppress the Wnt/β-catenin pathway partly through RPN2. Finally, a tumor xenograft model was applied to validate the biological function of circTOP2A in vivo. Taken together, our findings reveal the critical role of circTOP2A in promoting glioma proliferation and invasion via a ceRNA mechanism and provide an exploitable biomarker and therapeutic target for glioma patients.     

MiR-1207 overexpression promotes cancer stem cell–like traits in ovarian cancer by activating the Wnt/β-catenin signaling pathway

Wnt/β-catenin signaling pathway is strictly controlled by multiple negative regulators. However, how tumor cells override the negative regulatory effects to maintain constitutive activation of Wnt/β-catenin signaling, which is commonly observed in various cancers, remains puzzling. In current study, we reported that overexpression of miR-1207 in ovarian cancer activated Wnt/β-catenin signaling by directly targeting and suppressing secreted Frizzled-related protein 1 (SFRP1), AXIN2 and inhibitor of β-catenin and TCF-4 (ICAT), which are vital negative regulators of the Wnt/β-catenin pathway. We found that the expression of miR-1207 was ubiquitously upregulated in both ovarian cancer tissues and cells, which inversely correlated with patient overall survival. Furthermore, overexpression of miR-1207 enhanced, while silencing miR-1207 reduced, stem cell-like traits of ovarian cancer cells in vitro and in vivo, including tumor sphere formation capability and proportion of SP+ and CD133+ cells. Importantly, upregulating miR-1207 promoted, while silencing miR-1207 inhibited, the tumorigenicity of ovarian cancer cells. Hence, our results suggest that miR-1207 plays a vital role in promoting the cancer stem cell-like phenotype in ovarian cancer and might represent a potential target for anti-ovarian cancer therapy.     

MicroRNA-200a suppresses the Wnt/β-catenin signaling pathway by interacting with β-catenin

The Wnt/β-catenin signaling pathway is crucial for human organ development and is involved in tumor progression of many cancers. Accumulating evidence suggests that the expression of β-catenin is, in part, regulated by specific microRNAs (miRNAs). The purpose of this study was to determine the expression of a recently identified epithelial to mesenchymal transition (EMT)-associated tumor suppressor microRNA (miR)-200a, in cancer cells. We also aimed to identify specific miR-200a target genes and to investigate the antitumor effects of miR-200a on the Wnt/β-catenin signaling pathway. We employed TOP/FOP flash luciferase assays to identify the effect of miR-200a on the Wnt/β-catenin pathway and we confirmed our observations using fluorescence microscopy. To determine target genes of miR-200a, a 3' untranslated region (3' UTR) luciferase assay was performed. Cell viability, invasion and wound healing assays were carried out for functional analysis after miRNA transfection. We further investigated the role of miR-200a in EMT by Western blot analysis. We found fluctuation in the expression of miR-200a that was accompanied by changes in the expression of members of the Wnt/β-catenin signaling pathway. We also determined that miR-200a can directly interact with the 3' UTR of CTNNB1 (the gene that encodes β-catenin) to suppress Wnt/β-catenin signaling. MiR-200a could also influence the biological activities of SGC790 and U251 cells. Our results demonstrate that miR-200a is a new tumor suppressor that can regulate the activity of the Wnt/β-catenin signaling pathway via two mechanisms. MiR-200a is a candidate target for tumor treatment via its regulation of the Wnt/β-catenin signaling pathway.     

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.     

miR-122/Wnt/β-catenin regulatory circuitry sustains glioma progression

Malignant glioma is the most common type of human intracranial cancer and has poor prognosis due to its high recurrence and invasiveness. However, the molecular mechanisms underlying its malignant phenotypes have still not been completely explored yet. miR-122 has been well documented to act as a tumor suppressor for hepatocellular carcinoma and breast cancer, but the implication of miR-122 in the progression of glioma is not clear yet. In this study, we found that miR-122 was underexpressed in glioma specimens and glioma cell lines, compared with normal brain tissues and cell lines. The expression of miR-122 levels is inversely correlated with the survival of patients after surgery. Overexpression of miR-122 by an adenoviral vector suppressed the proliferation and colony formation of glioma cells. The in vivo tumorigenicity of U-87 MG cells was also greatly compromised by restoring miR-122. miR-122 suppressed the activation of Wnt/β-catenin pathway in glioma cells. Interestingly, Wnt/β-catenin signaling conversely reduced the expression of miR-122 in glioma cells, maybe in a hepatocyte nuclear factor (HNF)-dependent mechanism. Taken together, we revealed that there is a miR-122/Wnt/β-catenin regulatory circuitry existing in glioma cells that contributes to glioma progression.     

MiR-328 promotes glioma cell invasion via SFRP1-dependent Wnt-signaling activation

Background

Diffusely infiltrative growth of human astrocytic gliomas is one of the major obstacles to successful tumor therapy. Thorough insights into the molecules and pathways signaling glioma cell invasion thus appear of major relevance for the development of targeted and individualized therapies. By miRNA expression profiling of microdissected human tumor biopsy specimens we identified miR-328 as one of the main miRNAs upregulated in invading glioma cells in vivo and further investigated its role in glioma pathogenesis.

Methods

We employed miRNA mimics and inhibitors to functionally characterize miR-328, 3′ untranslated region luciferase assays, and T-cell factor/lymphoid enhancer factor reporter assays to pinpoint miR-328 targets and signaling pathways, and analyzed miR-328 expression in a large panel of gliomas.

Results

First, we corroborated the invasion-promoting role of miR-328 in A172 and TP365MG glioma cells. Secreted Frizzled-related protein 1 (SFRP1), an inhibitor of Wnt signaling, was then pinpointed as a direct miR-328 target. SFRP1 expression is of prognostic relevance in gliomas with reduced expression, being associated with significantly lower overall patient survival in both the Repository of Molecular Brain Neoplasia Data (REMBRANDT) and The Cancer Genome Atlas. Of note, miR-328 regulated both SFRP1 protein expression levels and Wnt signaling pathway activity. Finally, in human glioma tissues miR-328 appeared to account for the downregulation of SFRP1 preferentially in lower-grade astrocytic gliomas and was inversely related to SFRP1 promoter hypermethylation.

Conclusion

Taken together, we report on a novel molecular miR-328–dependent mechanism that via SFRP1 inhibition and Wnt activation contributes to the infiltrative glioma phenotype at already early stages of glioma progression, with unfavorable prognostic implications for the final outcome of the disease.     

MicroRNA-188-5p targeting Forkhead Box L1 promotes colorectal cancer progression via activating Wnt/β-catenin signaling

Objective: MicroRNA-188-5p (miR-188) enhances oncologic progression in various human malignancies. This study aimed to explore its role in colorectal cancer (CRC). Materials and Methods: Human CRC tissues paired with normal tissues, and several CRC cell lines were utilized. Real-time quantitative PCR was applied to measure the expression of miR-188. Overexpression and knockdown were used to access the function of miR-188 and to investigate whether FOXL1/Wnt signaling mediates such function. The proliferation, migration and invasion of cancer cells were evaluated by CCK8, wound-healing and transwell assays, respectively. Whether FOXL1 acted as a direct target of miR-188 was verified by dual-luciferase reporter assays. Results: Levels of miR-188 were upregulated in CRC tissues than in paired-normal tissues, as well as in various CRC cell lines. High expression of miR-188 was strongly associated with advanced tumor stage, accompanied with significant tumor cell proliferation, invasion and migration. It was confirmed that FOXL1 played positive crosstalk between miR-188 regulation and downstream Wnt/β-catenin signaling activation. Conclusions: All findings indicate that miR-188 promotes CRC cell proliferation and invasion through targeting FOXL1/Wnt signaling and could be served as a potential therapeutic target for human CRC in the future.     

miR-1471对胶质瘤细胞增殖、侵袭和迁移能力的影响及其机制探讨

目的:探讨miR-1471对胶质瘤细胞增殖、侵袭和迁移能力的影响及其机制。方法:体外培养人胶质瘤细胞U251,将miR-1471模拟物或阴性对照分别转染至细胞中,记为miR-1471组和阴性对照（NC组）,同时设置对照组。qRT-PCR检测转染效果。CCK8检测各组细胞增殖能力。Transwell实验检测各组细胞侵袭能力。划痕实验检测各组细胞迁移能力。qRT-PCR和Western blot检测转移黏附基因（metadherin, MTDH）及Wnt/β-catenin信号通路相关基因和蛋白的表达。结果:与对照组和NC组比较,miR-1471组细胞增殖活性均显著降低（P＜0.05）,侵袭细胞数均显著减少（P＜0.05）,划痕间距明显较大,细胞中MTDH、Wnt1和β-catenin mRNA和蛋白表达水平均显著降低（P＜0.05）。结论:miR-1471能抑制人胶质瘤细胞U251的增殖、侵袭和迁移能力,其作用机制可能与下调MTDH表达,抑制Wnt/β-catenin信号通路的激活有关。     

Wnt2 promotes non-small cell lung cancer progression by activating WNT/β-catenin pathway

Background: Wnt2 is overexpressed and able to promote tumorigenesis in many types of cancer. However, its expression and role in lung cancer has not been well clarified yet. In this study, we aims to investigate the expression pattern, clinical significance and the underlying molecular mechanism of Wnt2 in non-small lung cancer (NSCLC). Methods: Immunohistochemical staining and ELISA assays were applied to detect Wnt2 level in tumor tissue and serum. EDU incorporation assays and colony formation assays were used to evaluate the growth-promoting effect of Wnt2 in vitro. Then we performed western blot and immunofluorescence assays to detect the activation of WNT signaling pathway. Finally mice engrafted with NSCLC tumor cells were used to assess the role of Wnt2 in vivo. Results: Immunohistochemical staining consisting of 264 NSCLC tumor tissues showed that a high level of Wnt2 was associated with a poor overall survival (OS) and relapse-free survival (RFS) of NSCLC patients (P = 0.002 and 0.0005, respectively). Multivariate analysis presented that Wnt2 level in tumor tissue was an independent prognostic factor (P = 0.049 for OS and P = 0.002 for RFS, respectively). Furthermore, ELISA assays for 181 individuals (116 NSCLC and 65 controls) revealed that serum Wnt2 levels in adenocarcinoma was significantly higher than that in healthy volunteers (P < 0.0001). In vitro H460 cell line stably overexpressing Wnt2 showed enhanced growth activity than the control cells whereas knockdown of Wnt2 by siRNA in H1299 cells resulted in decreased growth activity. Additionally, Wnt2 level in tumor tissues was significantly associated with Ki-67 level (rs: 0.316; P < 0.0001). Immunofluorescence and Western blot assays detected the translocation of β-catenin from cytoplasm into nucleus, which indicated that Wnt2 probably promotes proliferation by activating WNT/β-catenin pathway. In vivo H460 cells expressing exogenous Wnt2 showed increased growth-promoting effect in Balb/c nude mice than control cells. Conclusions: The present study for the first time suggested that Wnt2 was both a prognostic and a diagnostic biomarker for NSCLC. Tumor-derived Wnt2 can promote growth activity of NSCLC cells through activating WNT/β-catenin signaling pathway.     

MicroRNA-15a-5p inhibits endometrial carcinoma proliferation,invasion and migration via downregulation of VEGFA and inhibition of the Wnt/β-catenin signaling pathway

Endometrial carcinoma (EC) is one of the most common malignant gynecological tumors. Dysregulation of microRNAs (miRNAs/miRs) is frequently identified in human tumors, playing key regulatory roles in tumor growth and metastasis. The present study aimed to explore the functions and potential mechanisms of miR-15a-5p in EC progression. RT-qPCR was used to detect the expression levels of miR-15a-5p and vascular endothelial growth factor A (VEGFA) mRNA. Western blot analysis was performed to examine the expression of related proteins. Functional assays, including proliferation and Transwell assays were performed to determine the roles of miR-15a-5p in EC progression. TargetScan and luciferase reporter assays were used to explore the potential target genes of miR-15a-5p. The results revealed that miR-15a-5p was underexpressed in EC tissue samples in comparison with that in matched normal tissue samples. The expression level of miR-15a-5p was associated with the clinicopathologic characteristics of EC patients. Notably, both in vitro and in vivo assays revealed that miR-15a-5p upregulation significantly inhibited EC growth and metastasis. Furthermore, bioinformatics analysis and dual luciferase reporter assay indicated that VEGFA was a candidate target of miR-15a-5p. Mechanistic investigation revealed that miR-15a-5p inhibited EC development via regulation of Wnt/β-catenin pathway and targeting of VEGFA. In summary, the present results demonstrated that miR-15a-5p could inhibit EC development and may serve as a promising therapeutic biomarker in EC.     

HEF1, a novel target of Wnt signaling, promotes colonic cell migration and cancer progression

Misregulation of the canonical Wnt/β-catenin pathway and aberrant activation of Wnt signaling target genes are common in colorectal cancer (CRC) and contribute to cancer progression. Altered expression of human enhancer of filamentation 1 (HEF1; also known as NEDD9 or Cas-L) has been implicated in progression of melanoma, breast, and CRC. However, the regulation of HEF1 and the role of HEF1 in CRC tumorigenesis are not fully understood. We here identify HEF1 as a novel Wnt signaling target. The expression of HEF1 was upregulated by Wnt-3a, β-catenin, and Dvl2 in a dose-dependent manner, and was suppressed following β-catenin downregulation by shRNA. In addition, elevated HEF1 mRNA and protein levels were observed in CRC cell lines and primary tumor tissues, as well as in the colon and adenoma polyps of Apc(Min/+) mice. Moreover, HEF1 levels in human colorectal tumor tissues increased with the tumor grade. Chromatin immunoprecipitation (ChIP) assays and promoter analyses revealed three functional T-cell factor (TCF)-binding sites in the promoter of HEF1 responsible for HEF1 induction by Wnt signaling. Ectopic expression of HEF1 increased cell proliferation and colony formation, while downregulation of HEF1 in SW480 cells by shRNA had the opposite effects and inhibited the xenograft tumor growth. Furthermore, overexpression of HEF1 in SW480 cells promoted cell migration and invasion. Together, our results determined a novel role of HEF1 as a mediator of the canonical Wnt/β-catenin signaling pathway for cell proliferation, migration, and tumorigenesis, as well as an important player in colorectal tumorigenesis and progression. HEF1 may represent an attractive candidate for drug targeting in CRC.     

miRNA-101通过靶向CDK8调控结肠癌细胞侵袭和Wnt/β-catenin通路活化

目的 探讨miRNA-101（miR-101）通过靶向CDK8对结肠癌细胞侵袭和Wnt/β-catenin通路激活的影响。方法 采用qRT-PCR和Western blot测定结肠癌组织、癌旁正常组织及五种结肠癌细胞株中miR-101和CDK8的表达。双荧光素酶报告实验测定其相互作用关系。通过miR-101 mimic、pBabe-CDK8转染调控CDK8表达并测定其对肿瘤细胞侵袭和Wnt/β-catenin激活的影响。结果 与癌旁正常组织相比,miR-101在结肠癌组织中表达水平显著降低,而CDK8的表达显著增加。双荧光素酶报告实验证实miR-101可直接与CDK8 3'UTR的结合位点作用调节荧光素酶的活性。转染miR-101 mimic组细胞的侵袭能力比阴性对照组和CDK8组明显下降。转染miR-101 mimic后TOP/FOP荧光素酶活性显著降低,β-catenin的蛋白表达也出现下降。CDK8过表达载体转染能显著减弱miR-101 mimic对荧光素酶活性和β-catenin蛋白表达的作用。结论 miRNA-101可通过靶向CDK8调控结肠癌细胞侵袭和Wnt/β-catenin通路活化。     

微小RNA-223-3p靶向调控TGFBR3影响肺癌细胞上皮间质转化及Wnt/β-catenin通路

目的:探讨微小RNA-223-3p（miR-223-3p）对转化生长因子Ⅲ型受体（TGFBR3）的靶向调控及对肺癌上皮间质转化（EMT）及Wnt/β-catenin通路相关指标的影响。方法:采用实时荧光定量PCR（qPCR）检测肺癌细胞（95D、LTEP-α-2、A549及NCI-H460）以及人肺上皮细胞BEAS-2B的miR-223-3p和TGFBR3水平,经双荧光素酶报告基因实验验证miR-223-3p和TGFBR3的靶向关系。将A549细胞分成3组:对照组、miR-223-3p NC组（转染miR-223-3p NC）、miR-223-3p mimic组（转染miR-223-3p mimic）,MTT法、划痕实验及Transwell小室实验分别检测3组细胞的增殖及迁移能力。接着收集3组转染后的细胞,分别制备裸鼠移植瘤,处死裸鼠并剥离肿瘤组织,测量肿瘤体积及重量,免疫组化法对比各组镜下TGFBR3蛋白的表达情况,Western blotting实验检测EMT相关指标上皮钙黏蛋白（E-Cadherin）、神经型钙黏蛋白（N-Cadherin）、波形蛋白（Vimentin）及Wnt/β-catenin通路相关因子（Wnt1和β-catenin）的表达。结果:与BEAS-2B细胞对比,肺癌细胞miR-223-3p及TGFBR3的表达水平均降低,差异有统计学意义（P＜0.05）;miR-223-3p能靶向调控TGFBR3的表达。miR-223-3p mimic组A549细胞的增殖活力、划痕愈合率及穿膜细胞数均较miR-223-3p NC组明显降低（P＜0.05）;此外,miR-223-3p mimic组裸鼠瘤体体积及重量均明显低于miR-223-3p NC组。免疫组化结果显示,miR-223-3p mimic组TGFBR3阳性表达率上升,与miR-223-3p NC组相比,差异具有统计学意义（P＜0.05）;Western blotting结果提示,与miR-223-3p NC组相比,miR-223-3p mimic组肿瘤组织中TGFBR3、E-Cadherin表达水平升高,而N-Cadherin、Vimentin、Wnt1和β-catenin表达水平均下降（P＜0.05）。对照组与miR-223-3p NC组的增殖活力、划痕愈合能力以及EMT和Wnt/β-catenin通路相关因子水平的差异无统计学意义（P＞0.05）。结论:miR-223-3p在肺癌中异常低表达,miR-223-3p通过靶向调控TGFBR3来抑制肺癌A549细胞的增殖、迁移侵袭、EMT过程并阻断Wnt/β-catenin通路,在肺癌进展中发挥抑癌作用。