Estrogen nuclear receptors affect cell migration by altering sublocalization of AQP2 in glioma cell lines

Shu Wan,Chuanming Zheng,Xia Zhai,Ning Wang,Xiangwei Fei,Juanjuan Jiang,Xiuxiu Jiang,Ruijin Wu

doi:10.1038/s41420-018-0113-y

Abstract

Glioblastomas are capable of infiltrating into neighboring brain tissues. The prognosis of a male patient is worse than that of women. Here, we demonstrate the effects of estrogen on invasion of glioma cells via regulating estrogen nuclear receptors (ERα and ERβ) combined with aquaporin 2 (AQP2). In our study, we conclude that AQP2 was located mainly in the nuclei of the glioma cell lines and is capable of inhibiting cell invasion. According to the gene ontology analysis, out of 138 screened genes, three genes of ankyrin repeat and FYVE domain containing 1 (ANKFY1), lymphocyte transmembrane adaptor 1 (LAX1), and latent transforming growth factor beta-binding protein 1 (LTBP1) were found to be regulating the ERα and ERβ. The expression of ERα was found to be high, whereas the expression of both ERβ and AQP2 was low in glioma cells from patient tissues and glioblastoma cell lines. The expression levels of AQP2, ANKFY1, LAX1, and LTBP1 were upregulated by both ERα small interfering RNA (siRNA) and overexpression of ERβ. AQP2 inhibition of cell invasion was inversely influenced by LAX1siRNA. The luciferase report system indicated that AQP2 promoted the transcriptional activity of LAX1 and inhibited cell invasion. These data suggest that ERβ may function as AQP promoter in the nucleus to sustain cells' stability by promoting AQP production, while ERα acts as an antagonist of AQP2. The ratio between ERα and ERβ is likely to affect the distribution of AQP2 in the nucleus. Low level of ERβ reduces the inhibition of invasion of glioma cells influenced by high level of LAX1 expression, leading to an increase in the invasion ability of glioma cells.

Highlights

Glioblastomas are capable of infiltrating into neighboring brain tissues
Expression levels of aquaporin 2 (AQP2) and estrogen receptor (ER) in human glioma cells Based on the fluorescent staining (FS) results, we assume that AQP2 is located mainly in the outer part of the nuclei in glial and glioma cells in the tissues (Fig. 1a)
Overexpression of ERβ upregulated the mRNA levels of ANKFY, LAX, LTBP, and AQP2, while ERαsiRNA increased the mRNA levels of ANKFY, LAX, LTBP, and AQP2 compared to those of the control groups (Fig. 5j, k). These data indicated that ERα and ERβ play an inverse influence on AQP2. In this regard, the present study provided the following novel findings: (1) AQP2 expression was decreased in glioma cells in tissues; (2) AQP2 was located in all parts of glioma cells or glial cells in the tissues and was located mainly in the nuclei in cell lines; (3) E2 decreased AQP2 expression in cell lines, in the nucleus; (4) E2 promoted cell invasion by reducing AQP2 distribution in the nucleus; and (5) the plausible molecular mechanisms by which E2 regulates AQP2 sublocalization and promotes cell invasion occurrence at the nuclear and membrane levels

Summary

Introduction

Glioblastomas are capable of infiltrating into neighboring brain tissues. The prognosis of a male patient is worse than that of women. We demonstrate the effects of estrogen on invasion of glioma cells via regulating estrogen nuclear receptors (ERα and ERβ) combined with aquaporin 2 (AQP2). The luciferase report system indicated that AQP2 promoted the transcriptional activity of LAX1 and inhibited cell invasion These data suggest that ERβ may function as AQP promoter in the nucleus to sustain cells' stability by promoting AQP production, while ERα acts as an antagonist of AQP2. A growing body of evidence has suggested that AQPs could facilitate cell migration, invasion, and proliferation in tumor development with the aid of water transport[10,11]. Studies of tumor angiogenesis have revealed an unexpected function of AQPs in cell migration, invasion, and the spread of malignancy[12,13]. There is a lack of direct mechanistic evidence to explain AQP2 regulation of cell migration and invasion of glioma cells

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