LncRNA AGAP2-AS1 interacts with IGF2BP2 to promote bladder cancer progression via regulating LRG1 mRNA stability.

The long non-coding RNA (lncRNA) AGAP2-AS1 was implicated in tumorigenesis, yet with unclear mechanism in the development of Bladder Cancer (BCa). We collected the clinicopathological features and tissue samples of 45 patients with BCa in Xiangya Hospital. Expressions of AGAP2-AS1 and LRG1 were detected by RT-qPCR in BCa tissues and normal tissues as well as in BCa cells. The roles of AGAP2-AS1 and LRG1 were investigated by CCK-8, colony formation assay, transwell assays and tube formation assay. The subcellular localization of AGAP2-AS1 was detected by Fluorescence in situ hybridization. Bioinformatics method, RNA immunoprecipitation, RNA pull-down assay and Actinomycin D test were used to predict and identify the relationships between AGAP2-AS1, LRG1 and IGF2BP2. Xenografted tumors were produced to explore the function of AGAP2-AS1 in BCa in vivo. AGAP2-AS1 and LRG1 were highly upregulated in BCa. AGAP2-AS1 positively correlated with T stage, grade and vascular invasion, but negatively correlated with the survival of patients. Overexpressions of AGAP2-AS1 promoted proliferation, migration, invasion, tumor angiogenesis in vitro and tumor growth, metastasis in vivo, knockdown of AGAP2-AS1 exhibited the opposite effects. AGAP2-AS1 localized mainly in the cytoplasm. AGAP2-AS1 directly bound to IGF2BP2 protein to enhance LRG1 mRNA stability. Inhibition of BCa progression by AGAP2-AS1 knockdown may be reversed by LRG1 overexpression. AGAP2-AS1 can promote BCa progression and metastasis by recruiting IGF2BP2 to stabilize LRG1. LncRNA AGAP2-AS1 enhanced the stability of the LRG1 mRNA by recruiting the RNA-binding protein IGF2BP2 to the target gene LRG1 mRNA in the cytoplasm, so as to promot the proliferation, migration, invasion and angiogenesis of bladder cancer cells. [Display omitted] • We found AGAP2-AS1 was overexpressed in BCa, the high expression of AGAP2-AS1 was positively correlated with high pathological T stage, high grade and vascular invasion, but negatively correlated with the survival prognosis. High expression of AGAP2-AS1 and LRG1 promoted proliferation, migration, invasion of BCa cells and angiogenesis of tumor in vitro. AGAP2-AS1 also promoted tumor growth and metastasis in vivo. AGAP2-AS1 promoted the stability of LRG1 mRNA by recruiting the RNA binding protein IGF2BP2 to LRG1 mRNA. Morever, AGAP2-AS1 promoted uncontrolled proliferation, migration, invasion and angiogenesis of BCa cells in an LRG1-dependent manner, thereby accelerating the malignant progression of BCa. • According 45 BCa patients' tissues in our hospital, AGAP2-AS1 and LRG1 are upregulated in bladder cancer (BCa), pathological features such as pathological T stage, high grade, especially vascular infiltration were related to the level of AGAP2-AS1. • AGAP2-AS1 recruits IGF2BP2 to stabilize LRG1 mRNA in BCa, the co-localization of AGAP2-AS1, IGF2BP2 and LRG1 was confirmed by IF-FISH. • In addition to using bioinformatics methods to predict target genes, we employed a number of experimental methods to verify our conclusions. [ABSTRACT FROM AUTHOR]