Yunfei Wang

Long Noncoding RNANEAT1, Regulated by the EGFR Pathway, Contributes to Glioblastoma Progression Through the WNT/β-Catenin Pathway by Scaffolding EZH2

Purpose: Long noncoding RNAs have been implicated in gliomagenesis, but their mechanisms of action are mainly undocumented. Through public glioma mRNA expression data sets, we found that NEAT1 was a potential oncogene. We systematically analyzed the clinical significance and mechanism of NEAT1 in glioblastoma. Experimental Design: Initially, we evaluated whether NEAT1 expression levels could be regulated by EGFR pathway activity. We subsequently evaluated the effect of NEAT1 on the WNT/β-catenin pathway and its target binding gene. The animal model supported the experimental findings. Results: We found that NEAT1 levels were regulated by EGFR pathway activity, which was mediated by STAT3 and NFκB (p65) downstream of the EGFR pathway. Moreover, we found that NEAT1 was critical for glioma cell growth and invasion by increasing β-catenin nuclear transport and downregulating ICAT, GSK3B, and Axin2. Taken together, we found that NEAT1 could bind to EZH2 and mediate the trimethylation of H3K27 in their promoters. NEAT1 depletion also inhibited GBM cell growth and invasion in the intracranial animal model. Conclusions: The EGFR/NEAT1/EZH2/β-catenin axis serves as a critical effector of tumorigenesis and progression, suggesting new therapeutic directions in glioblastoma. Clin Cancer Res; 24(3); 684–95. ©2017 AACR.

Paracrine and epigenetic control of CAF-induced metastasis: the role of HOTAIR stimulated by TGF-ß1 secretion

BackgroundThe communication between carcinoma associated fibroblasts (CAFs) and cancer cells facilitate tumor metastasis. In this study, we further underlying the epigenetic mechanisms of CAFs feed the cancer cells and the molecular mediators involved in these processes.MethodsMCF-7 and MDA-MB-231 cells were treated with CAFs culture conditioned medium, respectively. Cytokine antibody array, enzyme-linked immunosorbent assay, western blotting and immunofluorescence were used to identify the key chemokines. Chromatin immunoprecipitation and luciferase reporter assay were performed to explore the transactivation of target LncRNA by CAFs. A series of in vitro assays was performed with RNAi-mediated knockdown to elucidate the function of LncRNA. An orthotopic mouse model of MDA-MB-231 was conducted to confirm the mechanism in vivo.ResultsHere we reported that TGF-β1 was top one highest level of cytokine secreted by CAFs as revealed by cytokine antibody array. Paracrine TGF-β1 was essential for CAFs induced EMT and metastasis in breast cancer cells, which is a crucial mediator of the interaction between stromal and cancer cells. CAF-CM significantly enhanced the HOTAIR expression to promote EMT, whereas treatment with small-molecule inhibitors of TGF-β1 attenuated the activation of HOTAIR. Most importantly, SMAD2/3/4 directly bound the promoter site of HOTAIR, located between nucleotides -386 and -398, -440 and -452, suggesting that HOTAIR was a directly transcriptional target of SMAD2/3/4. Additionally, CAFs mediated EMT by targeting CDK5 signaling through H3K27 tri-methylation. Depletion of HOTAIR inhibited CAFs-induced tumor growth and lung metastasis in MDA-MB-231 orthotopic animal model.ConclusionsOur findings demonstrated that CAFs promoted the metastatic activity of breast cancer cells by activating the transcription of HOTAIR via TGF-β1 secretion, supporting the pursuit of the TGF-β1/HOTAIR axis as a target in breast cancer treatment.

UBE2C induces EMT through Wnt/β‑catenin and PI3K/Akt signaling pathways by regulating phosphorylation levels of Aurora-A

The ubiquitin-conjugating enzyme 2C (UBE2C) is the key component in the ubiquitin proteasome system (UPS) by partnering with the anaphase-promoting complex (APC/C). A high UBE2C protein expression level has been reported in various types of human tumors. However, little is known about the precise mechanism by which UBE2C expression is downregulated in gastric cancer. We found in MGC-803 and SGC-7901 gastric cancer cells UBE2C-deficient G2/M phase arrest in the cell cycle and subsequently decreased gastric adenocarcinoma tumorigenesis. In the previous study, we identified Aurora-A (AURKA) as the hub gene of the gastric cancer linkage network based genome-wide association study (eGWAS). Furthermore, knockdown of UBE2C using siRNA markedly reduced the level of phosphorylation AURKA (p-AURKA) via Wnt/β-catenin and PI3K/Akt signaling pathways suppressed the occurrence and development of gastric cancer. Additionally, the expression of E-cadherin was up-regulated and N-cadherin was down-regulated in response to UBE2C knockdown and inhibits epithelial-mesenchymal transition (EMT). Collectively, our data suggest that the activity of AURKA might be regulated by UBE2C through regulating the activity of APC/C. UBE2C may be a new marker in the diagnosis of gastric cancer and may be a potential therapeutic target for the treatment of gastric adenocarcinoma.

Abstract 997: Hotair promotes glioma cell cycle through a b-catenin mediated mRNA network

Background: LncRNA hotair is an oncogene that involves in the progression of several cancers. Previously we and others have reported that hotair promotes glioblastoma progression by regulating cell cycle. However, further mechanism still needs to be explored. The wnt/b-catenin signaling pathway is a crucial factor in the development of many cancers. B-catenin is a nuclear transcription factor that regulates multiple genes involved in cell proliferation, survival and EMT that contribute to glioma development. Methods: Positive correlation genes of hotair were picked up from CGGA (Chinese Glioma Genome Atlas) database by bioinformatics analysis. Real Time PCR is used to test the mRNA expression levels in U87 cells and astrocytes. Western blot is emplored to determine PKM2 expression after knocking down hotair. Further more, and nude mouse glioma intracranial model is employed to examine in vivo impact of hotair on GBM. Results: Hotair is a cell cycle related lncRNA as previously reported. Bioinformatics analysis indicated that various genes play important roles on cell cycle are positively correlated with hotair. Theses genes might be the executors of hotair on cell cycle regulating. We constructed a top 18 hotair-related genes network by connectivity. To test the hypothesis, we knock down hotair expression in U87 cells, and found out that FOXM1, CCNA2, CEP55, CENEP, CCNB2, HMMR, NCAPG, NUSAP were down-regulated significantly. In addition, overexpression of hotair in astrocytes could upregulate the mRNA of those genes. To further explore the regulatory mechanism, we analyed the promoter of these hotair-regulated genes and found out b-catenin/TCF4 binding site on all of them. This indicated that hotair might upregulate cell cycle associated genes through b-catenin/TCF4 pathway. FH535 is an inhibitor of wnt/b-catenin. The mRNA expression of these genes could be suppressed by FH535 treatment, which confirms the promoter analysis. It is reported that PKM2 could promote b-catenin nuclear translocation. Interestingly, we found out that binding site of miR-330 exists on both of hotair and PKM2 mRNA. Knocking-down of hotair inhibited PKM2 mRNA and protein expression in U87, U87vIII, U251 and LN229 cells. Further more, hotair siRNA could inhibit glioma growth in vivo. Conclusion: Our data indicated that hotair promotes glioma cell cycle through a b-catenin mediated mRNA network, and hotair could be a a biomarker and therapeutic target in glioblastoma. Meanwhile, there are still a lot of work to be done. Citation Format: Qixue Wang, Kai Huang, Yu Ren, Yunfei Wang, Bingcong Zhou, Yanli Tan, Chuan Fang, Jie Li, Chunsheng Kang. Hotair promotes glioma cell cycle through a b-catenin mediated mRNA network. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 997.