Genome-wide crosstalk between steroid receptors in breast and prostate cancers

Systemic glucocorticoids and the risk of breast cancer in a large nationwide case-control study

BACKGROUND

Concerns have been raised that long-term use of glucocorticoids may increase the risk of breast cancer, yet evidence is limited. Thus, this study investigated the association between systemic glucocorticoid use and breast cancer risk, overall and by breast cancer subtype and stage.

METHODS

A nationwide case-control study was conducted using the Danish healthcare registries. Women with invasive breast cancer between 2001 and 2018 (n = 67,829) were identified as cases. Each case was matched to 10 population controls on age and calendar time. Ever users of glucocorticoids were defined as women who filled at least 2 prescriptions and long-term users those who filled prescriptions equivalent to ≥ 1000 defined daily doses (DDDs). Conditional logistic regressions were performed to calculate odds ratios (ORs) and 95% confidence intervals for the associations between glucocorticoid use and breast cancer risk.

RESULTS

Twelve percent of women (n = 87,277) had ever been exposed to glucocorticoids and fewer than 1% were long-term users (n = 5,574). No association was found between ever use of glucocorticoids and breast cancer risk [OR = 1.00 (0.98-1.03)], compared with never use. However, an inverse association was observed between long-term glucocorticoid use and breast cancer risk [OR = 0.87 (0.77-0.97)], with suggestion of a slight dose-response relationship [OR per 500 DDDs = 0.96 (0.94-0.99)]. The associations were consistent across different tumour subtypes, estrogen receptor status, or clinical stage at diagnosis.

CONCLUSION

The findings from this large nationwide study did not suggest a positive association between glucocorticoids and breast cancer risk.

TRIM24 promotes T-cell lymphoma development and glucocorticoid resistance via FUS-mediated phase separation of the glucocorticoid receptor

T-cell lymphoma (TCL) is an aggressive malignancy with poor therapeutic outcomes, where glucocorticoid (GC) resistance remains a major challenge. Here, we identify TRIM24 as a critical regulator of GC receptor (GR) activity and a potential therapeutic target in TCL. TRIM24 deficiency delays TCL progression in murine models, suppresses cell proliferation, and enhances GC sensitivity by restoring GR transcriptional activity, as evidenced by transcriptomic and chromatin profiling. Mechanistically, TRIM24 interacts with Fused In Sarcoma (FUS) and promotes its liquid-liquid phase separation (LLPS) with GR, leading to impaired GR activity and heightened GC resistance. Moreover, TRIM24 is overexpressed in peripheral T-cell lymphoma (PTCL) samples, correlating with suppressed GR signaling and poor therapeutic response. These findings uncover an unrecognized "double-check" mechanism in which TRIM24 regulates nuclear GR function through FUS-facilitated LLPS. Importantly, targeting TRIM24 may provide a novel therapeutic strategy not only for overcoming GC resistance in TCL but also for addressing broader GR-dependent diseases.

Androgen Receptors in Human Breast Cancer and Female Canine Mammary Tumors

This review explores the potential role of androgens in human breast cancer and female canine mammary tumors. Human breast cancer is one of the most common cancers affecting women globally, while female canine mammary tumors provide a natural model for the study of human breast cancer due to their similar histopathologies and molecular features. Androgen receptors, typically linked to male sex hormones, are present in up to 90% of human breast tumors. These receptors interact with estrogen-receptor signaling, suggesting their involvement in a complex mechanism in cancer progression. Androgen receptors have become key players in breast cancer biology, offering new targets for therapeutic strategies. The presence of these receptors in both human and canine tumors raises important questions about their role in the development of these malignancies. While the exact mechanisms remain to be fully elucidated, research suggests that targeting androgen-receptor signaling could be a novel therapeutic approach for both humans and canines. Further studies are necessary to fully understand the implications of androgen-receptor expression and to develop more effective targeted therapies for these cancers.

Incidence and Prognostic Significance of Hormonal Receptors and HER2 Status Conversion in Recurrent Breast Cancer: A Retrospective Study in a Single Institute

Background and Objectives: Changes in biomarker status are not rare and usually occur in an unfavorable direction. Evaluating changes in biomarker status is advantageous for assessing treatment options and prognosticating patients. Currently, only a few studies have explored the association between biomarker conversion and breast cancer relapse. In this study, we sought to determine the incidence of receptor conversions in patients diagnosed with recurrent breast cancer in comparison to their corresponding primary tumors and to evaluate possible influencing factors. Moreover, we aimed to assess the prognostic significance of biomarker conversion, if any was detected, in breast cancer patients. Materials and Methods: A retrospective cohort study was conducted among breast cancer patients treated at King Khalid University Hospital, Riyadh, Saudi Arabia. Data were collected from recurrent breast cancer patients about different parameters to assess the incidence of hormonal receptors and human epidermal growth factor 2 (HER2) status conversion between primary and recurrent tumors. The calculation of progression-free survival (PFS)/ relapse-free survival (RFS) and the overall survival (OS) was conducted to assess the prognostic value of the assessed biomarker conversion. Results: Progesterone receptor (PR) conversion had the highest incidence (29.9%), followed by HER2 (23%) and estrogen receptor (ER) (12.6%). Menopausal status and concurrent receptor conversion were significant factors influencing receptor status changes. However, no significant associations were found between receptor conversion and other clinical factors, including tumor stage and histological subtype. The survival analysis revealed no statistically significant differences in OS or RFS between patients with and without receptor conversion. Conclusions: Receptor conversion, particularly for PR and HER2, is common in recurrent breast cancer, emphasizing the importance of re-biopsy at recurrence to ensure accurate treatment decisions. While receptor conversion does not significantly impact survival outcomes in this cohort, further large-scale prospective studies are warranted to validate these findings and explore their clinical implications in breast cancer management.

Transcription factors and hormone receptors: Sex‑specific targets for cancer therapy (Review)

Despite advancements in diagnostic and therapeutic technologies, cancer continues to pose a challenge to disease-free longevity in humans. Numerous factors contribute to the onset and progression of cancer, among which sex differences, as an intrinsic biological condition, warrant further attention. The present review summarizes the roles of hormone receptors estrogen receptor α (ERα), estrogen receptor β (ERβ) and androgen receptor (AR) in seven types of cancer: Breast, prostate, ovarian, lung, gastric, colon and liver cancer. Key cancer-related transcription factors known to be activated through interactions with these hormone receptors have also been discussed. To assess the impact of sex hormone receptors on different cancer types, hormone-related transcription factors were analyzed using the SignaLink 3.0 database. Further analysis focused on six key transcription factors: CCCTC-binding factor, forkhead box A1, retinoic acid receptor α, PBX homeobox 1, GATA binding protein 2 and CDK inhibitor 1A. The present review demonstrates that these transcription factors significantly influence hormone receptor activity across various types of cancer, and elucidates the complex interactions between these transcription factors and hormone receptors, offering new insights into their roles in cancer progression. The findings suggest that targeting these common transcription factors could improve the efficacy of hormone therapy and provide a unified approach to treating various types of cancer. Understanding the dual and context-dependent roles of these transcription factors deepens the current understanding of the molecular mechanisms underlying hormone-driven tumor progression and could lead to more effective targeted therapeutic strategies.

Intrauterine administration of peripheral blood mononuclear cells helps manage recurrent implantation failure by normalizing dysregulated gene expression including estrogen-responsive genes in mice

BACKGROUND

Intrauterine peripheral blood mononuclear cell (PBMC) therapy for recurrent implantation failure (RIF) has been reported to improve embryo implantation by acting on the endometrium. However, the exact mode of action of PBMC on the endometrium of patients with RIF remains unclear. In addition, the differences in the therapeutic effects of PBMC therapy with and without human chorionic gonadotropin (hCG) are unknown. Therefore, in this study, we investigated the changes in the endometrium during the implantation phase induced by PBMC administration and the differences in the efficacy of this therapy with and without hCG using a mouse model of implantation failure (IF).

METHODS

IF model was established by the subcutaneous administration of low-dose RU486. Pregnant mice were randomly divided into five groups: control, IF, culture medium, PBMC, and PBMC-hCG (the latter three groups were IF model mice with intrauterine administration). The pregnancy rate and the number and size of implantation sites were recorded during early pregnancy (day 7.5). Uteri from the preimplantation phase (evening of day 3.5) were collected and analyzed using RNA-sequencing (RNA-seq).

RESULTS

The pregnancy rate, the number of implantation sites, and the number of normal-sized implantation sites were significantly decreased in the IF model and were improved in the medium, PBMC, and PBMC-hCG groups. RNA-seq data showed that PBMC treatment normalized the expression of the majority of dysregulated genes in the endometrium during the preimplantation phase in the IF model, especially the overexpression of estrogen-activated genes. In addition, PBMC treatment increased the expression of local glucocorticoid receptors and suppressed the expression of inflammation-related genes, whereas no significant changes in blood estradiol and glucocorticoid levels were observed. These changes were more pronounced in the PBMC-hCG group and were consistent with the pregnancy outcomes.

CONCLUSIONS

Intrauterine administration of PBMC before embryo implantation promoted embryo implantation in the IF mouse model, and hCG enhanced pregnancy outcomes. PBMC modulated steroid receptor expression and suppressed inflammation and excessive estrogen action.

Mechanistic insights into steroid hormone-mediated regulation of the androgen receptor gene

Expression of the androgen receptor is key to the response of cells and tissues to androgenic steroids, such as testosterone or dihydrotestosterone, as well as impacting the benefit of hormone-dependent therapies for endocrine diseases and hormone-dependent cancers. However, the mechanisms controlling androgen receptor expression are not fully understood, limiting our ability to effectively promote or inhibit androgenic signalling therapeutically. An autoregulatory loop has been described in which androgen receptor may repress its own expression in the presence of hormone, although the molecular mechanisms are not fully understood. In this work, we elucidate the mechanisms of autoregulation and demonstrate, for the first time, that a similar repression of the AR gene is facilitated by the progesterone receptor. We show that the progesterone receptor, like the androgen receptor binds to response elements within the AR gene to effect transcriptional repression in response to hormone treatment. Mechanistically, this repression involves hormone-dependent histone deacetylation within the AR 5'UTR region and looping between sequences in intron 2 and the transcription start site (TSS). This novel pathway controlling AR expression in response to hormone stimulation may have important implications for understanding cell or tissue selective receptor signalling.

Glucocorticoid receptor action in prostate cancer: the role of transcription factor crosstalk

Prostate cancer is one of the most prevalent malignancies and is primarily driven by aberrant androgen receptor (AR) signaling. While AR-targeted therapies form the cornerstone of prostate cancer treatment, they often inadvertently activate compensatory pathways, leading to therapy resistance. This resistance is frequently mediated through changes in transcription factor (TF) crosstalk, reshaping gene regulatory programs and ultimately weakening treatment efficacy. Consequently, investigating TF interactions has become crucial for understanding the mechanisms driving therapy-resistant cancers. Recent evidence has highlighted the crosstalk between the glucocorticoid receptor (GR) and AR, demonstrating that GR can induce prostate cancer therapy resistance by replacing the inactivated AR, thereby becoming a driver of the disease. In addition to this oncogenic role, GR has also been shown to act as a tumor suppressor in prostate cancer. Owing to this dual role and the widespread use of glucocorticoids as adjuvant therapy, it is essential to understand GR's actions across different stages of prostate cancer development. In this review, we explore the current knowledge of GR in prostate cancer, with a specific focus on its crosstalk with other TFs. GR can directly and indirectly interact with a variety of TFs, and these interactions vary significantly depending on the type of prostate cancer cells. By highlighting these crosstalk interactions, we aim to provide insights that can guide the research and development of new GR-targeted therapies to mitigate its harmful effects in prostate cancer.

Differential role of glucocorticoid receptor based on its cell type specific expression on tumor cells and infiltrating lymphocytes

BACKGROUND

The glucocorticoid receptor (GR) is frequently expressed in breast cancer (BC), and its prognostic implications are contingent on estrogen receptor (ER) status. To address conflicting reports and explore therapeutic potential, a GR signature (GRsig) independent of ER status was developed. We also investigated cell type-specific GR protein expression in BC tumor epithelial cells and infiltrating lymphocytes.

METHODS

GRsig was derived from Dexamethasone treated cell lines through a bioinformatic pipeline. Immunohistochemistry assessed GR protein expression. Associations between GRsig and tumor phenotypes (proliferation, cytolytic activity (CYT), immune cell distribution, and epithelial-to-mesenchymal transition (EMT) were explored in public datasets. Single-cell RNA sequencing data evaluated context-dependent GR roles, and a cell type-specific prognostic role was assessed in an independent BC cohort.

RESULTS

High GRsig levels were associated with a favorable prognosis across BC subtypes. Tumor-specific high GRsig correlated with lower proliferation, increased CYT, and anti-tumorigenic immune cells. Single-cell data analysis revealed higher GRsig expression in immune cells, negatively correlating with EMT while a positive correlation was observed with EMT primarily in tumor and stromal cells. Univariate and multivariate analyses demonstrated the robust and independent predictive capability of GRsig for favorable prognosis. GR protein expression on immune cells in triple-negative tumors indicated a favorable prognosis.

CONCLUSION

This study underscores the cell type-specific role of GR, where its expression on tumor cells is associated with aggressive features like EMT, while in infiltrating lymphocytes, it predicts a better prognosis, particularly within TNBC tumors. The GRsig emerges as a promising independent prognostic indicator across diverse BC subtypes.

Glucocorticoid receptor signaling: intricacies and therapeutic opportunities

The glucocorticoid receptor (GR) is a major nuclear receptor (NR) drug target for the treatment of inflammatory disorders and several cancers. Despite the effectiveness of GR ligands, their systemic action triggers a plethora of side effects, limiting long-term use. Here, we discuss new concepts of and insights into GR mechanisms of action to assist in the identification of routes toward enhanced therapeutic benefits. We zoom in on the communication between different GR domains and how this is influenced by different ligands. We detail findings on the interaction between GR and chromatin, and highlight how condensate formation and coregulator confinement can perturb GR transcriptional responses. Last, we discuss the potential of novel ligands and the therapeutic exploitation of crosstalk with other NRs.

EP300/CREBBP acetyltransferase inhibition limits steroid receptor and FOXA1 signaling in prostate cancer cells

The androgen receptor (AR) is a primary target for treating prostate cancer (PCa), forming the bedrock of its clinical management. Despite their efficacy, resistance often hampers AR-targeted therapies, necessitating new strategies against therapy-resistant PCa. These resistances involve various mechanisms, including AR splice variant overexpression and altered activities of transcription factors like the glucocorticoid receptor (GR) and FOXA1. These factors rely on common coregulators, such as EP300/CREBBP, suggesting a rationale for coregulator-targeted therapies. Our study explores EP300/CREBBP acetyltransferase inhibition's impact on steroid receptor and FOXA1 signaling in PCa cells using genome-wide techniques. Results reveal that EP300/CREBBP inhibition significantly disrupts the AR-regulated transcriptome and receptor chromatin binding by reducing the AR-gene expression. Similarly, GR's regulated transcriptome and receptor binding were hindered, not linked to reduced GR expression but to diminished FOXA1 chromatin binding, restricting GR signaling. Overall, our findings highlight how EP300/CREBBP inhibition distinctively curtails oncogenic transcription factors' signaling, suggesting the potential of coregulatory-targeted therapies in PCa.

Glucocorticoid receptor: a harmonizer of cellular plasticity in breast cancer-directs the road towards therapy resistance, metastatic progression and recurrence

Recent therapeutic advances have significantly uplifted the quality of life in breast cancer patients, yet several impediments block the road to disease-free survival. This involves unresponsiveness towards administered therapy, epithelial to mesenchymal transition, and metastatic progression with the eventual appearance of recurrent disease. Attainment of such characteristics is a huge adaptive challenge to which tumour cells respond by acquiring diverse phenotypically plastic states. Several signalling networks and mediators are involved in such a process. Glucocorticoid receptor being a mediator of stress response imparts prognostic significance in the context of breast carcinoma. Involvement of the glucocorticoid receptor in the signalling cascade of breast cancer phenotypic plasticity needs further elucidation. This review attempted to shed light on the inter-regulatory interactions of the glucocorticoid receptor with the mediators of the plasticity program in breast cancer; which may provide a hint for strategizing therapeutics against the glucocorticoid/glucocorticoid receptor axis so as to modulate phenotypic plasticity in breast carcinoma.

Chromatin accessibility and pioneer factor FOXA1 restrict glucocorticoid receptor action in prostate cancer

Treatment of prostate cancer relies predominantly on the inhibition of androgen receptor (AR) signaling. Despite the initial effectiveness of the antiandrogen therapies, the cancer often develops resistance to the AR blockade. One mechanism of the resistance is glucocorticoid receptor (GR)-mediated replacement of AR function. Nevertheless, the mechanistic ways and means how the GR-mediated antiandrogen resistance occurs have remained elusive. Here, we have discovered several crucial features of GR action in prostate cancer cells through genome-wide techniques. We detected that the replacement of AR by GR in enzalutamide-exposed prostate cancer cells occurs almost exclusively at pre-accessible chromatin sites displaying FOXA1 occupancy. Counterintuitively to the classical pioneer factor model, silencing of FOXA1 potentiated the chromatin binding and transcriptional activity of GR. This was attributed to FOXA1-mediated repression of the NR3C1 (gene encoding GR) expression via the corepressor TLE3. Moreover, the small-molecule inhibition of coactivator p300's enzymatic activity efficiently restricted GR-mediated gene regulation and cell proliferation. Overall, we identified chromatin pre-accessibility and FOXA1-mediated repression as important regulators of GR action in prostate cancer, pointing out new avenues to oppose steroid receptor-mediated antiandrogen resistance.

Imbalanced glucocorticoid and mineralocorticoid stress hormone receptor function has sex-dependent and independent regulatory effects in the mouse hippocampus

Many stress-related neuropsychiatric disorders display pronounced sex differences in their frequency and clinical symptoms. Glucocorticoids are primary stress hormones that have been implicated in the development of these disorders but whether they contribute to the observed sex bias is poorly understood. Glucocorticoids signal through two closely related nuclear receptors, the glucocorticoid (GR) and mineralocorticoid receptor (MR). To elucidate the sex-specific and independent actions of glucocorticoids in the hippocampus, we developed knockout mice lacking hippocampal GR, MR, or both GR and MR. Mice deficient in hippocampal MR or both GR and MR showed an altered molecular phenotype of CA2 neurons and reduced anxiety-like behavior in both sexes, but altered stress adaptation behavior only in females and enhanced fear-motivated cue learning only in males. All three knockout mouse models displayed reduced sociability but only in male mice. Male and female mice deficient in both hippocampal GR and MR exhibited extensive neurodegeneration in the dentate gyrus. Global transcriptomic analysis revealed a marked expansion in the number of dysregulated genes in the hippocampus of female knockout mice compared to their male counterparts; however, the overall patterns of gene dysregulation were remarkably similar in both sexes. Within and across sex comparisons identified key GR and MR target genes and associated signaling pathways underlying the knockout phenotypes. These findings define major sex-dependent and independent effects of GR/MR imbalances on gene expression and functional profiles in the hippocampus and inform new strategies for treating men and women with stress-related neuropsychiatric disorders.

Crosstalk between glucocorticoid and mineralocorticoid receptors boosts glucocorticoid-induced killing of multiple myeloma cells

The glucocorticoid receptor (GR) is a crucial drug target in multiple myeloma as its activation with glucocorticoids effectively triggers myeloma cell death. However, as high-dose glucocorticoids are also associated with deleterious side effects, novel approaches are urgently needed to improve GR action in myeloma. Here, we reveal a functional crosstalk between GR and the mineralocorticoid receptor (MR) that plays a role in improved myeloma cell killing. We show that the GR agonist dexamethasone (Dex) downregulates MR levels in a GR-dependent way in myeloma cells. Co-treatment of Dex with the MR antagonist spironolactone (Spi) enhances Dex-induced cell killing in primary, newly diagnosed GC-sensitive myeloma cells. In a relapsed GC-resistant setting, Spi alone induces distinct myeloma cell killing. On a mechanistic level, we find that a GR-MR crosstalk likely arises from an endogenous interaction between GR and MR in myeloma cells. Quantitative dimerization assays show that Spi reduces Dex-induced GR-MR heterodimerization and completely abolishes Dex-induced MR-MR homodimerization, while leaving GR-GR homodimerization intact. Unbiased transcriptomics analyses reveal that c-myc and many of its target genes are downregulated most by combined Dex-Spi treatment. Proteomics analyses further identify that several metabolic hallmarks are modulated most by this combination treatment. Finally, we identified a subset of Dex-Spi downregulated genes and proteins that may predict prognosis in the CoMMpass myeloma patient cohort. Our study demonstrates that GR-MR crosstalk is therapeutically relevant in myeloma as it provides novel strategies for glucocorticoid-based dose-reduction.

Krüppel-like factor 9 (KLF9) links hormone dysregulation and circadian disruption to breast cancer pathogenesis

BACKGROUND

Circadian disruption is an emerging driver of breast cancer (BCa), with epidemiological studies linking shift work and chronic jet lag to increased BCa risk. Indeed, several clock genes participate in the gating of mitotic entry, regulation of DNA damage response, and epithelial-to-mesenchymal transition, thus impacting BCa etiology. Dysregulated estrogen (17β-estradiol, E2) and glucocorticoid (GC) signaling prevalent in BCa may further contribute to clock desynchrony by directly regulating the expression and cycling dynamics of genes comprising the local breast oscillator. In this study, we investigated the tumor suppressor gene, Krüppel-like factor 9 (KLF9), as an important point of crosstalk between hormone signaling and the circadian molecular network, and further examine its functional role in BCa.

METHODS

Through meta-analysis of publicly available RNA- and ChIP-sequencing datasets from BCa tumor samples and cell lines, and gene expression analysis by RT-qPCR and enhancer- reporter assays, we elucidated the molecular mechanism behind the clock and hormone regulation of KLF9. Lentiviral knockdown and overexpression of KLF9 in three distinct breast epithelial cell lines (MCF10A, MCF7 and MDA-MB-231) was generated to demonstrate the role of KLF9 in orthogonal assays on breast epithelial survival, proliferation, apoptosis, and migration.

RESULTS

We determined that KLF9 is a direct GC receptor target in mammary epithelial cells, and that induction is likely mediated through coordinate transcriptional activation from multiple GC-responsive enhancers in the KLF9 locus. More interestingly, rhythmic expression of KLF9 in MCF10A cells was abolished in the highly aggressive MDA-MB-231 line. In turn, forced expression of KLF9 altered the baseline and GC/E2-responsive expression of several clock genes, indicating that KLF9 may function as a regulator of the core clock machinery. Characterization of the role of KLF9 using complementary cancer hallmark assays in the context of the hormone-circadian axis revealed that KLF9 plays a tumor-suppressive role in BCa regardless of molecular subtype. KLF9 potentiated the anti-tumorigenic effects of GC in E2 receptor + luminal MCF7 cells, while it restrained GC-enhanced oncogenicity in triple-negative MCF10A and MDA-MB-231 cells.

CONCLUSIONS

Taken together, our findings support that dysregulation of KLF9 expression and oscillation in BCa impinges on circadian network dynamics, thus ultimately affecting the BCa oncogenic landscape.

SOX2 Modulates the Nuclear Organization and Transcriptional Activity of the Glucocorticoid Receptor

Steroid receptors (SRs) are ligand-dependent transcription factors (TFs) relevant to key cellular processes in both physiology and pathology, including some types of cancer. SOX2 is a master TF of pluripotency and self-renewal of embryonic stem cells, and its dysregulation is also associated with various types of human cancers. A potential crosstalk between these TFs could be relevant in malignant cells yet, to the best of our knowledge, no formal study has been performed thus far. Here we show, by quantitative live-cell imaging microscopy, that ectopic expression of SOX2 disrupts the formation of hormone-dependent intranuclear condensates of many steroid receptors (SRs), including those formed by the glucocorticoid receptor (GR). SOX2 also reduces GR's binding to specific DNA targets and modulates its transcriptional activity. SOX2-driven effects on GR condensates do not require the intrinsically disordered N-terminal domain of the receptor and, surprisingly, neither relies on GR/SOX2 interactions. SOX2 also alters the intranuclear dynamics and compartmentalization of the SR coactivator NCoA-2 and impairs GR/NCoA-2 interactions. These results suggest an indirect mechanism underlying SOX2-driven effects on SRs involving this coactivator. Together, these results highlight that the transcriptional program elicited by GR relies on its nuclear organization and is intimately linked to the distribution of other GR partners, such as the NCoA-2 coactivator. Abnormal expression of SOX2, commonly observed in many tumors, may alter the biological action of GR and, probably, other SRs as well. Understanding this crosstalk may help to improve steroid hormone-based therapies in cancers with elevated SOX2 expression.

The Role of Glucocorticoids in Breast Cancer Therapy

Glucocorticoids (GCs) are anti-inflammatory and immunosuppressive steroid molecules secreted by the adrenal gland and regulated by the hypothalamic-pituitary-adrenal (HPA) axis. GCs present a circadian release pattern under normal conditions; they increase their release under stress conditions. Their mechanism of action can be via the receptor-independent or receptor-dependent pathway. The receptor-dependent pathway translocates to the nucleus, where the ligand-receptor complex binds to specific sequences in the DNA to modulate the transcription of specific genes. The glucocorticoid receptor (GR) and its endogenous ligand cortisol (CORT) in humans, and corticosterone in rodents or its exogenous ligand, dexamethasone (DEX), have been extensively studied in breast cancer. Its clinical utility in oncology has mainly focused on using DEX as an antiemetic to prevent chemotherapy-induced nausea and vomiting. In this review, we compile the results reported in the literature in recent years, highlighting current trends and unresolved controversies in this field. Specifically, in breast cancer, GR is considered a marker of poor prognosis, and a therapeutic target for the triple-negative breast cancer (TNBC) subtype, and efforts are being made to develop better GR antagonists with fewer side effects. It is necessary to know the type of breast cancer to differentiate the treatment for estrogen receptor (ER)-positive, ER-negative, and TNBC, to implement therapies that include the use of GCs.

Inhibiting 3βHSD1 to eliminate the oncogenic effects of progesterone in prostate cancer

Prostate cancer continuously progresses following deprivation of circulating androgens originating from the testis and adrenal glands, indicating the existence of oncometabolites beyond androgens. In this study, mass-spectrometry-based screening of clinical specimens and a retrospective analysis on the clinical data of prostate cancer patients indicate the potential oncogenic effects of progesterone in patients. High doses of progesterone activate canonical and non-canonical androgen receptor (AR) target genes. Physiological levels of progesterone facilitate cell proliferation via GATA2. Inhibitors of 3β-hydroxysteroid dehydrogenase 1 (3βHSD1) has been discovered and shown to suppress the generation of progesterone, eliminating its transient and accumulating oncogenic effects. An increase in progesterone is associated with poor clinical outcomes in patients and may be used as a predictive biomarker. Overall, we demonstrate that progesterone acts as an oncogenic hormone in prostate cancer, and strategies to eliminate its oncogenic effects may benefit prostate cancer patients.

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High doses of progesterone activate canonical and non-canonical AR signaling

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Progesterone of physiological levels exerts its chronic oncogenic effect via GATA2

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Targeting 3βHSD1 to suppress progesterone synthesis blocks its oncogenic effects

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Serum progesterone might be a predictive biomarker for abiraterone response

Mechanisms behind context-dependent role of glucocorticoids in breast cancer progression

Glucocorticoids (GCs), mostly dexamethasone (dex), are routinely administered as adjuvant therapy to manage side effects in breast cancer. However, recently, it has been revealed that dex triggers different effects and correlates with opposite outcomes depending on the breast cancer molecular subtype. This has raised new concerns regarding the generalized use of GC and suggested that the context-dependent effects of GCs can be taken into potential consideration during treatment design. Based on this, attention has recently been drawn to the role of the glucocorticoid receptor (GR) in development and progression of breast cancer. Therefore, in this comprehensive review, we aimed to summarize the different mechanisms behind different context-dependent GC actions in breast cancer by applying a multilevel examination, starting from the association of variants of the GR-encoding gene to expression at the mRNA and protein level of the receptor, and its interactions with other factors influencing GC action in breast cancer. The role of GCs in chemosensitivity and chemoresistance observed during breast cancer therapy is discussed. In addition, experiences using GC targeting therapeutic options (already used and investigated in preclinical and clinical trials), such as classic GC dexamethasone, selective glucocorticoid receptor agonists and modulators, the GC antagonist mifepristone, and GR coregulators, are also summarized. Evidence presented can aid a better understanding of the biology of context-dependent GC action that can lead to further advances in the personalized therapy of breast cancer by the evaluation of GR along with the conventional estrogen receptor (ER) and progesterone receptor (PR) in the routine diagnostic procedure.