Estrogen Receptor β Regulates LncRNA HOTAIR Expression And Drives Renal Cell Carcinoma Progression

OBJECTIVE:To explore the role of estrogen receptor(ERβ)in the progression of renal cell carcinoma(RCC)by excavating large sample clinical database and relevant experiments,and to screen out the major downstream lncRNA influencing ERβ’s biological function effect on RCC.METHODS:The correlations between ERβ and clinical parameters(grade,stage,overall survival time,progression-free survival time)were analyzed by TCGA RCC clinical database.High-throughput sequencing technique was used to detect the oncogenes and lncRNA related to the progression of RCC which regulated by ERβ.The regulation of lncRNA was further confirmed by qRT-PCR and IF-FISH.The expression of ERβ and lncRNA was modulated by packaging lentivirus.And the effects on biological behavior such as proliferation was measured by CCK8 assay and invasion measured by Transwell invasion assay.The upstream and downstream relationship was determined by a rescue approach.The regulation mechanism was studied by combining bioinformatics prediction,luciferase reporter gene assay and mutation assay.RESULTS:TCGA database indicated a negative correlation between ERβ and survival time of patients with RCC.The higher the expression of ERβ,the shorter the total/progression-free survival length.Next generation RNA-seq screening found that ERβ significantly regulated lncRNA HOTAIR expression among others.TCGA database demonstrated a negative correlation between HOTAIR and survival,and a positive correlation between ERβ and HOTAIR expression level.Cellular experiments showed that ERβ could significantly upregulate the proliferation and invasion of RCC cells.Reversely modulating HOTAIR could partially reverse the effect of ERβ on RCC,suggesting that ERβ’s effect was mainly mediated by HOTAIR.Animal experiments showed that ERβ silencing suppressed RCC growth and metastasis capability significantly.The luciferase reporter gene assay and the mutant assay suggested that ERβ could upregulate HOTAIR transcription by binding on to the estrogen receptor response element(ERE)in the HOTAIR promoter region.CONCLUSION:HOTAIR is upregulated by ERβ as a nuclear transcription factor.ERβ-HOTAIR signal axis significantly increases RCC cell proliferation and invasion and promotes RCC progression.The discovery of this novel signal axis provides us with a new concept and data support for further improvement on RCC patient survival prediction and precision treatment against metastasis.