Context-Dependent Role of Glucocorticoid Receptor Alpha and Beta in Breast Cancer Cell Behaviour

Cells. 2023 Mar 1;12(5):784. doi: 10.3390/cells12050784.

Abstract

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.

Keywords: breast cancer; breast cancer progression; glucocorticoid receptor; glucocorticoid receptor alpha; glucocorticoid receptor beta; metastasis; migration; proliferation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breast Neoplasms*
  • Female
  • Glucocorticoids* / pharmacology
  • Humans
  • Ligands
  • Protein Isoforms

Substances

  • glucocorticoid receptor alpha
  • Glucocorticoids
  • Ligands
  • Protein Isoforms

Grants and funding

This work was supported by a Hungarian Scientific Research Grant of the National Research, Development and Innovation Office NKFI FK 135065, the New National Excellence Program of the Ministry of Human Capacities (UNKP-22-5-SE-1) given to H.B., and by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-EGA/TKP2021-NVA/TKP2021-NKTA funding scheme, given to A.P. H.B. is a recipient of the Bolyai Research Fellowship of the Hungarian Academy of Sciences. H.B. and A.P. acknowledge financial support from the National Laboratories Excellence program (under the National Tumour Biology Laboratory project (NLP17)) and the Hungarian Thematic Excellence Programme (TKP2021-EGA-44).