背景。已经观察到GCs在乳腺癌中的双重作用;然而,由于许多伴随因素,GR在癌症生物学中的作用仍然是模糊的。在这项研究中,我们旨在阐明GR在乳腺癌中的上下文依赖性作用。方法。GR表达在多个队列中表征:(1)在RNA水平上的24,256个乳腺癌标本,220个蛋白质水平的样品,并与临床病理数据相关;(2)雌激素受体(ER)阳性和阴性细胞系用于测试ER和配体的存在,以及Grα和Grβ过表达后Grβ同工型对GR作用的影响,通过体外功能测定。结果。我们发现,与ER+乳腺癌细胞相比,ER-乳腺癌细胞中的GR表达更高,GR-反式激活基因主要与细胞迁移有关。免疫组织化学显示主要是细胞质,但与ER状态无关。GRα增加细胞增殖,生存能力,和ER细胞的迁移。GRβ对乳腺癌细胞活力也有类似的影响,扩散,和移民。然而,根据ER的存在,GRβ亚型具有相反的作用:与ER-乳腺癌细胞相比,ER+乳腺癌细胞中的死细胞比率增加.有趣的是,Grα和Grβ的作用不依赖于配体的存在,暗示“内在”的作用,GR在乳腺癌中的配体非依赖性作用。Conclusions.使用不同GR抗体的染色差异可能是文献中有关GR蛋白表达和临床病理数据的有争议发现背后的原因。因此,免疫组织化学的解释应谨慎。通过剖析Grα和Grβ的作用,我们发现,在ER的背景下,GR的存在对癌细胞行为有不同的影响,但独立于配体的可用性。此外,GR-反式激活基因主要参与细胞迁移,这提高了GR在疾病进展中的重要性。
Background. The dual role of GCs has been observed in breast cancer; however, due to many concomitant factors, GR action in cancer biology is still ambiguous. In this study, we aimed to unravel the context-dependent action of GR in breast cancer. Methods. GR expression was characterized in multiple cohorts: (1) 24,256 breast cancer specimens on the RNA level, 220 samples on the protein level and correlated with clinicopathological data; (2) oestrogen receptor (ER)-positive and -negative cell lines were used to test for the presence of ER and ligand, and the effect of the GRβ isoform following GRα and GRβ overexpression on GR action, by in vitro functional assays. Results. We found that GR expression was higher in ER- breast cancer cells compared to ER+ ones, and GR-transactivated genes were implicated mainly in cell migration. Immunohistochemistry showed mostly cytoplasmic but heterogenous staining irrespective of ER status. GRα increased cell proliferation, viability, and the migration of ER- cells. GRβ had a similar effect on breast cancer cell viability, proliferation, and migration. However, the GRβ isoform had the opposite effect depending on the presence of ER: an increased dead cell ratio was found in ER+ breast cancer cells compared to ER- ones. Interestingly, GRα and GRβ action did not depend on the presence of the ligand, suggesting the role of the \"intrinsic\", ligand-independent action of GR in breast cancer. Conclusions. Staining differences using different GR antibodies may be the reason behind controversial findings in the literature regarding the expression of GR protein and clinicopathological data. Therefore, caution in the interpretation of immunohistochemistry should be applied. By dissecting the effects of GRα and GRβ, we found that the presence of the GR in the context of ER had a different effect on cancer cell behaviour, but independently of ligand availability. Additionally, GR-transactivated genes are mostly involved in cell migration, which raises GR\'s importance in disease progression.