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

Abstract

Abstract 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.