The glucocorticoid receptor (GR) has been implicated in tumor progression and therapy resistance, yet its role in ovarian cancer (OC) remains controversial. In particular, how GR integrates environmental cues to control OC plasticity and therapeutic responses is poorly understood. We investigated GR function in ovarian cancer (OC) cells by integrating genetic and pharmacological approaches. By using both OC cell lines and patient-derived cells, we performed a comprehensive set of phenotypic, molecular and functional assays alongside genome-wide transcriptomic analyses. We also extended these analyses to physiologically relevant 3D systems, including tumor spheroids and organotypic cultures, to better recapitulate the in vivo tumor microenvironment. We provided unprecedented evidence that GR modulates OC behavior in a context-dependent manner. Under 2D culture conditions, GR enhanced cellular heterogeneity, epithelial–mesenchymal transition and migration, thereby increasing cisplatin resistance. Conversely, in a 3D context, GR exerted a marked yet reversible antiproliferative effect, characterized by reduced protein synthesis and adaptative stress responses. Mechanistically, GR activity converged on inhibition of glycolysis and activation of gluconeogenesis. Indeed, pharmacological inhibition of glycolysis with 2-deoxyglucose phenocopied GR-induced mesenchymalization in 2D cultures and growth inhibition in 3D models. Moreover, inhibition of gluconeogenesis with metformin prevented the GR-dependent antiproliferative effect in 3D models. Consistently, the glucocorticoid budesonide further potentiates the anti-proliferative effects of GR in OC spheroids. Transcriptomic analyses revealed that GR regulates gene programs involved in extracellular matrix organization and cell adhesion, uncovering a previously unrecognized role for GR in tumor microenvironment remodeling. Our findings reveal distinct, context-dependent effect of GR in OC cells, whereby GR activation promotes chemoresistance and migratory behavior in 2D cultures, while inducing a reversible slow proliferative state under 3D conditions. These results underscore the importance of cellular context in interpreting GR activity and suggest that selective GR modulators, including budesonide, may offer new therapeutic avenues for treating advanced-stage OC.
Girolamo et al. (Thu,) studied this question.