Microarray Analysis Reveals Glucocorticoid-Regulated Survival Genes That Are Associated With Inhibition of Apoptosis in Breast Epithelial Cells

Glucocorticoid receptor-mediated oncogenic activity is dependent on breast cancer subtype

Breast cancer incidence has been steadily rising and is the leading cause of cancer death in women due to its high metastatic potential. Individual breast cancer subtypes are classified by both cell type of origin and receptor expression, namely estrogen, progesterone and human epidermal growth factor receptors (ER, PR and HER2). Recently, the importance and context-dependent role of glucocorticoid receptor (GR) expression in the natural history and prognosis of breast cancer subtypes have been uncovered. In ER-positive breast cancer, GR expression is associated with a better prognosis as a result of ER-GR crosstalk. GR appears to modulate ER-mediated gene expression resulting in decreased tumor cell proliferation and a more indolent cancer phenotype. In ER-negative breast cancer, including GR-positive triple-negative breast cancer (TNBC), GR expression enhances migration, chemotherapy resistance and cell survival. In invasive lobular carcinoma, GR function is relatively understudied, and more work is required to determine whether lobular subtypes behave similarly to their invasive ductal carcinoma counterparts. Importantly, understanding GR signaling in individual breast cancer subtypes has potential clinical implications because of the recent development of highly selective GR non-steroidal ligands, which represent a therapeutic approach for modulating GR activity systemically.

Glucocorticoid receptors orchestrate a convergence of host and cellular stress signals in triple negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that lacks expression of the nuclear steroid receptors that bind estrogens (ER) and progestogens (PRs) and does not exhibit HER2 (Human epidermal growth factor 2) receptor overexpression. Even in the face of initially effective chemotherapies, TNBC patients often relapse. One primary cause for therapy-resistant tumor progression is the activation of cellular stress signaling pathways. The glucocorticoid receptor (GR), a corticosteroid-activated transcription factor most closely related to PR, is a mediator of both endocrine/host stress and local tumor microenvironment (TME)-derived and cellular stress responses. Interestingly, GR expression is associated with a good prognosis in ER+ breast cancer but predicts poor prognosis in TNBC. Classically, GR's transcriptional activity is regulated by circulating glucocorticoids. Additionally, GR is regulated by ligand-independent signaling events. Notably, the stress-activated protein kinase, p38 MAP kinase, phosphorylates GR at serine 134 (Ser134) in response to TME-derived growth factors and cytokines, including HGF and TGFβ1. Phospho-Ser134-GR (p-Ser134-GR) associates with cytoplasmic and nuclear signaling molecules, including 14-3-3ζ, aryl hydrocarbon receptors (AhR), and hypoxia-inducible factors (HIFs). Phospho-GR/HIF-containing transcriptional complexes upregulate gene sets whose protein products include the components of inducible oncogenic signaling pathways (PTK6) that further promote cancer cell survival, chemoresistance, altered metabolism, and migratory/invasive behavior in TNBC. Recent studies have implicated liganded p-Ser134-GR (p-GR) in dexamethasone-mediated upregulation of genes related to TNBC cell motility and dysregulated metabolism. Herein, we review the tumor-promoting roles of GR and discuss how both ligand-dependent and ligand-independent/stress signaling-driven inputs to p-GR converge to orchestrate metastatic TNBC progression.

Investigation of selective glucocorticoid receptor modulation in high-grade serous ovarian cancer PDX models

OBJECTIVE

In ovarian cancer (OvCa), tumor cell high glucocorticoid receptor (GR) has been associated with poor patient prognosis. In vitro, GR activation inhibits chemotherapy-induced OvCa cell death in association with transcriptional upregulation of genes encoding anti-apoptotic proteins. A recent randomized phase II study demonstrated improvement in progression-free survival (PFS) for heavily pre-treated OvCa patients randomized to receive therapy with a selective GR modulator (SGRM) plus chemotherapy compared to chemotherapy alone. We hypothesized that SGRM therapy would improve carboplatin response in OvCa patient-derived xenograft (PDX).

METHODS

Six high-grade serous (HGS) OvCa PDX models expressing GR mRNA (NR3C1) and protein were treated with chemotherapy +/- SGRM. Tumor size was measured longitudinally by peritoneal transcutaneous ultrasonography.

RESULTS

One of the 6 GR-positive PDX models showed a significant improvement in PFS with the addition of a SGRM. Interestingly, the single model with an improved PFS was least carboplatin sensitive. Possible explanations for the modest SGRM activity include the high carboplatin sensitivity of 5 of the PDX tumors and the potential that SGRMs activate the tumor invasive immune cells in patients (absent from immunocompromised mice). The level of tumor GR protein expression alone appears insufficient for predicting SGRM response.

CONCLUSION

The significant improvement in PFS shown in 1 of the 6 models after treatment with a SGRM plus chemotherapy underscores the need to determine predictive biomarkers for SGRM therapy in HGS OvCa and to better identify patient subgroups that are most likely to benefit from adding GR modulation to chemotherapy.

Glucocorticoid Receptor (GR) Activation Is Associated with Increased cAMP/PKA Signaling in Castration-Resistant Prostate Cancer

In castration-resistant prostate cancer (CRPC), increased glucocorticoid receptor (GR) expression and ensuing transcriptional activity have been proposed as an oncogenic "bypass" mechanism in response to androgen receptor (AR) signaling inhibition (ARSi). Here, we report that GR transcriptional activity acquired following ARSi is associated with the upregulation of cyclic adenosine monophosphate (cAMP)-associated gene expression pathways in both model systems and metastatic prostate cancer patient samples. In the context of ARSi, the expression of GR-mediated genes encoding cAMP signaling pathway-associated proteins can be inhibited by treatment with selective GR modulators (SGRMs). For example, in the context of ARSi, we found that GR activation resulted in upregulation of protein kinase inhibitor beta (PKIB) mRNA and protein levels, leading to nuclear accumulation of the cAMP-dependent protein kinase A catalytic subunit (PKA-c). Increased PKA-c, in turn, is associated with increased cAMP response element-binding protein phosphorylation and activity. Furthermore, enzalutamide and SGRM combination therapy in mice bearing CRPC xenografts delayed CRPC progression compared with enzalutamide therapy alone, and reduced tumor PKIB mRNA expression. Supporting the clinical importance of GR/PKA signaling activation in CRPC, we found a significant enrichment of both cAMP pathway signaling-associated gene expression and high NR3C1 (GR) activity in patient-derived xenograft models and metastatic human CRPC samples. These findings suggest a novel mechanism linking CRPC-induced GR transcriptional activity with increased cAMP signaling in AR-antagonized CRPC. Furthermore, our findings suggest that GR-specific modulation in addition to AR antagonism may delay GR+ CRPC time to recurrence, at least in part, by inhibiting tumor cAMP/PKA pathways.

The Potential of Hormonal Therapies for Treatment of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is considered one of the most aggressive forms of breast cancer with poor survival rates compared to other breast cancer subtypes. TNBC is characterized by the absence of the estrogen receptor alpha, progesterone receptor, and the human epidermal growth factor receptor 2, limiting those viable treatment options available to patients with other breast cancer subtypes. Furthermore, due to the particularly high heterogeneity of TNBC, conventional treatments such as chemotherapy are not universally effective, leading to drug resistance and intolerable side effects. Thus, there is a pressing need to discover new therapies beneficial to TNBC patients. This review highlights current findings regarding the roles of three steroid hormone receptors, estrogen receptor beta, the androgen receptor, and the glucocorticoid receptor, in the progression of TNBC. In addition, we discussed several ongoing and completed clinical trials targeting these hormone receptors in TNBC patients.

Chronic stress-induced immune dysregulation in breast cancer: Implications of psychosocial factors

Chronic stress refers to continuous emotional changes and psychological pressure that individuals experience when they are unable to adjust and stabilize the internal environment over an extended period. It can increase the pressure on endocrine mediators and cytokines in the circulation, as well as tissues throughout the hypothalamic-pituitary-adrenaline (HPA) axis and sympathetic nervous system (SNS); thus, evolving the internal environment of the tumor. This review assesses several key issues, involving psychosocial factors, and integrates clinical, cellular, and molecular studies-as well as the latest research progress-to provide a mechanistic understanding regarding breast oncopsychology. We propose that chronic stress contributes to large individual diferences in the prognosis of breast cancer survivors because they change the basic physiological processes of the endocrine and immune systems, which in turn regulate tumor growth. The study of psychological and physiological reactions of breast cancer patients suggests a new idea for psychological intervention and clinical treatment for breast cancer patients.

Prognostic Value of SGK1 and Bcl-2 in Invasive Breast Cancer

It is crucial to understand molecular alterations in breast cancer and how they relate to clinicopathologic factors. We have previously shown that the glucocorticoid receptor (GCR) protein expression was reduced in invasive breast carcinoma compared to normal breast tissue. Glucocorticoids, signaling through the GCR, regulate several cellular processes via downstream targets such as serum/glucocorticoid-regulated kinase 1 (SGK1) and B-cell lymphoma 2 (Bcl-2). We measured the expression of SGK1 and Bcl-2, in respective breast cancer tissue arrays, from a multiracial cohort of breast cancer patients. Higher cytoplasmic SGK1 staining was stronger in breast cancer tissue compared to normal tissue, especially in hormone receptor-negative cases. Conversely, the expression of cytoplasmic Bcl-2 was reduced in breast cancer compared to normal tissue, especially in hormone receptor-negative cases. Bcl-2 staining was associated with the self-reported racial/ethnic category, an earlier clinical stage, a lower histological grade, and a higher survival rate. Bcl-2 expression was associated with longer survival in models adjusted for age and race (HR = 0.32, 95% CI: 0.15, 0.65), and Bcl-2 expression remained strongly positively associated with protection from breast cancer death, with additional adjustments for ER/PR status (HR = 0.41, 95% CI: 0.2, 0.85). SGK1 and Bcl-2 may play biological roles in breast cancer development and/or progression.

Induction of SGK1 via glucocorticoid-influenced clinical outcome of triple-negative breast cancer patients

PURPOSE

Triple-negative breast cancer (TNBC) is a highly heterogeneous and aggressive breast malignancy. Glucocorticoid (GC)-glucocorticoid receptor (GR) pathway plays a pivotal role in the cellular responses to various stresses including chemotherapy. Serum- and glucocorticoid-induced kinase-1 (SGK1) is known as an important downstream effector molecule in the GR signaling pathway, we attempted to explore its clinicopathological and functional significance in TNBC in which GR is expressed.

METHODS

We first immunolocalized GR and SGK1 and correlated the results with clinicopathological variables and clinical outcome in 131 TNBC patients. We also evaluated the effects of SGK1 on the cell proliferation and migration in TNBC cell lines with administration of dexamethasone (DEX) to further clarify the significance of SGK1.

RESULTS

The status of SGK1 in carcinoma cells was significantly associated with adverse clinical outcome in TNBC patients examined and was significantly associated with lymph node metastasis, pathological stage, and lymphatic invasion of the patients. In particular, SGK1 immunoreactivity was significantly associated with an increased risk of recurrence in GR-positive TNBC patients. Subsequent in vitro studies also demonstrated that DEX promoted TNBC cell migration and the silencing of gene expression did inhibit the cell proliferation and migration of TNBC cells under DEX treatment.

CONCLUSIONS

To the best of our knowledge, this is the first study to explore an association between SGK1 and clinicopathological variables and clinical outcome of TNBC patients. SGK1 status was significantly positively correlated with adverse clinical outcome of TNBC patients and promoted carcinoma cell proliferation and migration of carcinoma cells.

Combating breast cancer progression through combination therapy with hypomethylating agent and glucocorticoid

Breast cancer is the leading cause of cancer-related death in women. Among breast cancer types, triple-negative breast cancer (TNBC) accounts for 15% of all breast cancers with aggressive tumor behavior. By using bioinformatic approaches, we observed that the microRNA-708 promoter is highly methylated in breast carcinomas, and this methylation is linked to a poor prognosis. Moreover, microRNA-708 expression correlates with better clinical outcomes in TNBC patients. Combination treatment with the hypomethylating agent decitabine and synthetic glucocorticoid significantly increased the expression of microRNA-708, reactivated DNMT-suppressed pathways, and decreased the expression of multiple metastasis-promoting genes such as matrix metalloproteinases (MMPs) and IL-1β, leading to the suppression of breast cancer cell proliferation, migration, and invasion, as well as reduced tumor growth and distant metastasis in the TNBC xenograft mouse model. Overall, our study reveals a therapeutic opportunity in which a combined regimen of decitabine with glucocorticoid may have therapeutic potential in treating TNBC patients.

Cationic lipid-conjugated bis-arylidene oxindole derivatives as broad-spectrum breast cancer-selective therapeutics

Breast cancer is a heterogeneous malignancy with wide-ranging variations in therapeutic responses, overall survival etc. Major challenges for available chemotherapeutic agents in achieving clinical success are in maintaining systemic bio-distribution and avoiding non-specific adverse effects. Bis-arylidene oxindoles are estrogen receptor (ER)-selective bioactive molecules with moderate potency. In here, we have designed, synthesized and evaluated a series of twin aliphatic chain cationic lipid-conjugated bis-arylidene oxindole molecules with variations in nature of linker, lengths of carbon spacer and hydrophobic twin chains. We observed that among the various structural analogues, C8 twin-chain containing molecules, PGC8, S2C8 and S3C8 showed effective cancer cell-selective cytotoxicity in different cancer cell lines with an IC₅₀ ranging from 4 to 7 µM. These molecules selectively induced apoptosis, ROS production and cell cycle inhibition at G1/S phase in ER + breast cancer cells but not in non-cancer cells. Additionally, these molecules formed homogenous self-assemblies exhibiting effective hydrodynamic diameter with positive surface charge. The self-assemblies also showed prominent cancer cell-selective uptake and DNA-binding abilities. Hence, we have shown successful incorporation of dexamethasone to the self-assemblies, and its enhanced cytotoxicity even in ER-negative breast cancer cells. All these results indicate that PGC8, S2C8 and S3C8 molecules, albeit their potent and selective ER-positive anti-breast cancer activity, can be repurposed as targeted delivery systems and hold promise as unique, broader spectrum breast cancer cell-selective therapeutic payloads.

Glucocorticoid mediated inhibition of LKB1 mutant non-small cell lung cancers

The glucocorticoid receptor (GR) is an important anti-cancer target in lymphoid cancers but has been understudied in solid tumors like lung cancer, although glucocorticoids are often given with chemotherapy regimens to mitigate side effects. Here, we identify a dexamethasone-GR mediated anti-cancer response in a subset of aggressive non-small cell lung cancers (NSCLCs) that harbor Serine/Threonine Kinase 11 (STK11/LKB1) mutations. High tumor expression of carbamoyl phosphate synthase 1 (CPS1) was strongly linked to the presence of LKB1 mutations, was the best predictor of NSCLC dexamethasone (DEX) sensitivity (p < 10-16) but was not mechanistically involved in DEX sensitivity. Subcutaneous, orthotopic and metastatic NSCLC xenografts, biomarker-selected, STK11/LKB1 mutant patient derived xenografts, and genetically engineered mouse models with KRAS/LKB1 mutant lung adenocarcinomas all showed marked in vivo anti-tumor responses with the glucocorticoid dexamethasone as a single agent or in combination with cisplatin. Mechanistically, GR activation triggers G1/S cell cycle arrest in LKB1 mutant NSCLCs by inducing the expression of the cyclin-dependent kinase inhibitor, CDKN1C/p57(Kip2). All findings were confirmed with functional genomic experiments including CRISPR knockouts and exogenous expression. Importantly, DEX-GR mediated cell cycle arrest did not interfere with NSCLC radiotherapy, or platinum response in vitro or with platinum response in vivo. While DEX induced LKB1 mutant NSCLCs in vitro exhibit markers of cellular senescence and demonstrate impaired migration, in vivo DEX treatment of a patient derived xenograft (PDX) STK11/LKB1 mutant model resulted in expression of apoptosis markers. These findings identify a previously unknown GR mediated therapeutic vulnerability in STK11/LKB1 mutant NSCLCs caused by induction of p57(Kip2) expression with both STK11 mutation and high expression of CPS1 as precision medicine biomarkers of this vulnerability.

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.

Chronic stress in solid tumor development: from mechanisms to interventions

Chronic stress results in disturbances of body hormones through the neuroendocrine system. Cancer patients often experience recurrent anxiety and restlessness during disease progression and treatment, which aggravates disease progression and hinders treatment effects. Recent studies have shown that chronic stress-regulated neuroendocrine systems secret hormones to activate many signaling pathways related to tumor development in tumor cells. The activated neuroendocrine system acts not only on tumor cells but also modulates the survival and metabolic changes of surrounding non-cancerous cells. Current clinical evidences also suggest that chronic stress affects the outcome of cancer treatment. However, in clinic, there is lack of effective treatment for chronic stress in cancer patients. In this review, we discuss the main mechanisms by which chronic stress regulates the tumor microenvironment, including functional regulation of tumor cells by stress hormones (stem cell-like properties, metastasis, angiogenesis, DNA damage accumulation, and apoptotic resistance), metabolic reprogramming and immune escape, and peritumor neuromodulation. Based on the current clinical treatment framework for cancer and chronic stress, we also summarize pharmacological and non-pharmacological therapeutic approaches to provide some directions for cancer therapy.

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.

Autophagy activation in breast cancer cells in vitro after the treatment with PI3K/AKT/mTOR inhibitors

Introduction. Current chemotherapy of breast cancer has a wide range of disadvantages, in particular, the development of therapy-related infections and hormonal imbalance. Combination of main cytostatic with glucocorticoids allows to broaden its therapeutic interval and to decrease the total toxicity of the treatment. However, long-term treatment with glucocorticoids leads to the development of severe side effects via activation of multiple molecular mechanisms. Thus, glucocorticoids activate prosurvival mTOR-dependent autophagy. Therefore, the evaluation of PI3K (phosphoinositide 3-kinases) / Akt (protein kinase B) / mTOR (mammalian target of rapamycin) inhibitors as adjuvants for breast cancer therapy is important for optimization of treatment protocol.Aim. Analysis of the effects of PI3K/Akt/mTOR inhibitors, rapamycin, wortmannin and LY-294002 in combination with glucocorticoids in breast cancer cell lines of different subtypes.Materials and methods. We demonstrated the inhibition of PI3K/Akt/mTOR signaling and the autophagy induction after the treatment of breast cancer cells with rapamycin, wortmannin and LY-294002 by Western blotting analysis of Beclin-1, phospho-Beclin-1 (Ser93 and Ser30).Conclusion. PI3K/Akt/mTOR inhibitors in combination with Dexamethasone cooperatively inhibited mTOR signaling and activated autophagy in breast cancer cells in vitro.

Stress and surgical diseases of thyroid gland in environment of the armed conflict (review of literature and own observations)

Stress and surgical diseases of thyroid gland in environment of the armed conflict (review of literature and own observations)

Surgical Stress and Cancer Progression: New Findings and Future Perspectives

PURPOSE OF REVIEW

The stress response to surgery is essential for maintaining homeostasis and exhibits anti-tumor effects; however, an ongoing and exaggerated stress response may have adverse clinical consequences and even promote cancer progression. This review will discuss the complex relationship between surgical stress and cancer progression.

RECENT FINDINGS

Surgical stress exhibits both anti-tumor and cancer-promoting effects by causing changes in the neuroendocrine, circulatory, and immune systems. Many studies have found that many mechanisms are involved in the process, and the corresponding targets could be applied for cancer therapy. Although surgical stress may have anti-tumor effects, it is necessary to inhibit an excessive stress response, mostly showing cancer-promoting effects.

Adverse outcome pathway from activation of the AhR to breast cancer-related death

Adverse outcome pathways (AOPs) are formalized and structured linear concepts that connect one molecular initiating event (MIE) to an adverse outcome (AO) via different key events (KE) through key event relationships (KER). They are mainly used in eco-toxicology toxicology, and regulatory health issues. AOPs must respond to specific guidelines from the Organization for Economic Co-operation and Development (OECD) to weight the evidence between each KE. Breast cancer is the deadliest cancer in women with a poor prognosis in case of metastatic breast cancer. The role of the environments in the formation of metastasis has been suggested. We hypothesized that activation of the AhR (MIE), a xenobiotic receptor, could lead to breast cancer related death (AO), through different KEs, constituting a new AOP. An artificial intelligence tool (AOP-helpfinder), which screens the available literature, was used to collect all existing scientific abstracts to build a novel AOP, using a list of key words. Four hundred and seven abstracts were found containing at least a word from our MIE list and either one word from our AO or KE list. A manual curation retained 113 pertinent articles, which were also screened using PubTator. From these analyses, an AOP was created linking the activation of the AhR to breast cancer related death through decreased apoptosis, inflammation, endothelial cell migration, angiogenesis, and invasion. These KEs promote an increased tumor growth, angiogenesis and migration which leads to breast cancer metastasis and breast cancer related death. The evidence of the proposed AOP was weighted using the tailored Bradford Hill criteria and the OECD guidelines. The confidence in our AOP was considered strong. An in vitro validation must be carried out, but our review proposes a strong relationship between AhR activation and breast cancer-related death with an innovative use of an artificial intelligence literature search.

Rewiring of the Endocrine Network in Triple-Negative Breast Cancer

The immunohistochemical definition of estrogen/progesterone receptors dictates endocrine feasibility in the treatment course of breast cancer. Characterized by the deficiency of estrogen receptor α, ERα-negative breast cancers are dissociated from any endocrine regimens in the routine clinical setting, triple-negative breast cancer in particular. However, the stereotype was challenged by triple-negative breast cancers’ retained sensitivity and vulnerability to endocrine agents. The interplay of hormone action and the carcinogenic signaling program previously underscored was gradually recognized along with the increasing investigation. In parallel, the overlooked endocrine-responsiveness in ERα-negative breast cancers attracted attention and supplied fresh insight into the therapeutic strategy in an ERα-independent manner. This review elaborates on the genomic and non-genomic steroid hormone actions and endocrine-related signals in triple-negative breast cancers attached to the hormone insensitivity label. We also shed light on the non-canonical mechanism detected in common hormone agents to showcase their pleiotropic effects.

Circadian clock synchrony and chronotherapy opportunities in cancer treatment

Cell-autonomous, tissue-specific circadian rhythms in gene expression and cellular processes have been observed throughout the human body. Disruption of daily rhythms by mistimed exposure to light, food intake, or genetic mutation has been linked to cancer development. Some medications are also more effective at certain times of day. However, a limited number of clinical studies have examined daily rhythms in the patient or drug timing as treatment strategies. This review highlights advances and challenges in cancer biology as a function of time of day. Recent evidence for daily rhythms and their entrainment in tumors indicate that personalized medicine should include understanding and accounting for daily rhythms in cancer patients.

Impact of Glucocorticoid Use in Oncology in the Immunotherapy Era

Thanks to their anti-inflammatory, anti-oedema, and anti-allergy properties, glucocorticoids are among the most widely prescribed drugs in patients with cancer. The indications for glucocorticoid use are very wide and varied in the context of cancer and include the symptomatic management of cancer-related symptoms (compression, pain, oedema, altered general state) but also prevention or treatment of common side effects of anti-cancer therapies (nausea, allergies, etc.) or immune-related adverse events (irAE). In this review, we first give an overview of the different clinical situations where glucocorticoids are used in oncology. Next, we describe the current state of knowledge regarding the effects of these molecules on immune response, in particular anti-tumour response, and we summarize available data evaluating how these effects may interfere with the efficacy of immunotherapy using immune checkpoint inhibitors.

Advantages and drawbacks of dexamethasone in glioblastoma multiforme

The most widespread, malignant, and deadliest type of glial tumor is glioblastoma multiforme (GBM). Despite radiation, chemotherapy, and radical surgery, the median survival of afflicted individuals is about 12 months. Unfortunately, existing therapeutic interventions are abysmal. Dexamethasone (Dex), a synthetic glucocorticoid, has been used for many years to treat brain edema and inflammation caused by GBM. Several investigations have recently shown that Dex also exerts antitumoral effects against GBM. On the other hand, more recent disputed findings have questioned the long-held dogma of Dex treatment for GBM. Unfortunately, steroids are associated with various undesirable side effects, including severe immunosuppression and metabolic changes like hyperglycemia, which may impair the survival of GBM patients. Current ideas and concerns about Dex's effects on GBM cerebral edema, cell proliferation, migration, and its clinical outcomes were investigated in this study.

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.

Expression of glucocorticoid receptor (GR) and clinical significance in adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare endocrine tumor, and most cases present with hormone excess with poor prognosis. Our research aims to determine the clinical and biological significance of glucocorticoid receptor (GR) expression using large cohorts of ACC patients. Immunohistochemistry was used to assess the expression of GR in 78 ACC cases from the West China Hospital (WCH) cohort. RNA-seq data were retrieved from The Cancer Genome Atlas database (TCGA, n=79). Clinicopathological and follow-up data were obtained from two cohorts. The correlation between the GR gene and tumor immune status was estimated using TIMER and GEPIA2. Kaplan-Meier analysis was performed to identify the prognostic value of GR in ACC. In the WCH cohort, positive nuclear GR staining was identified in 90% of the primary ACC cases. Cortisol-secreting ACCs demonstrated significantly lower GR protein expression than did nonfunctioning tumors (P<0.001). This finding was validated by the mRNA data analysis of the TCGA cohort (P = 0.030). GR expression was found to be positively correlated with the immune cell infiltration level and immune-checkpoint-related gene expression in ACC. Survival comparison and multivariate analysis showed that GR expression is an independent prognostic predictor of disease-free survival and overall survival in ACC patients in both cohorts. Our findings suggest that low GR expression is significantly correlated with excess cortisol, immune signatures and poor survival in ACC patients. We propose that GR signaling may play an important role in ACC behavior and thus may be a therapeutic target, which deserves further research.

Stress sensing within the breast tumor microenvironment: how glucocorticoid receptors live in the moment

The classification and treatment of breast cancer is largely defined by the expression of steroid hormone receptors (HRs), namely estrogen receptor (ER) and progesterone receptor (PR), and gene amplification/overexpression of human epidermal growth factor receptor 2 (HER2). More recently, studies of androgen receptor (AR), glucocorticoid receptor (GR), and mineralocorticoid receptor (MR) have revealed that targeting these related HRs may be a promising strategy for a more personalized approach to the treatment of specific subtypes of HR+ breast cancer. For example, GR expression is associated with a good prognosis in ER+ breast cancer, but predicts poor prognosis in triple-negative breast cancer (TNBC). GR, like ER, PRs, and AR, is a ligand-activated transcription factor, but also has significant ligand-independent signaling activities. GR transcriptional activity is classically regulated by circulating glucocorticoids (GCs; ligand-dependent). Recent studies demonstrate that GR transcriptional activity is also regulated by a variety of cellular stress stimuli that input to GR Ser134 phosphorylation via rapid activation of the p38 mitogen activated protein kinase (MAPK) signaling pathway (ligand-independent). Furthermore, ligand-independent GR activation promotes feedforward signaling loops that mediate sustained activation of stress signaling pathways to drive advanced cancer biology (i.e. migration, invasion, chemoresistance, survival, and cellular growth). In this review, we will focus on the role of GR as a key sensor and mediator of physiologic and tumor microenvironment (TME)-derived cellular stress signaling in TNBC and discuss how targeting GR and/or associated signaling pathways may provide a strategy to inhibit deadly TNBC progression.

Modulation of the oral glucocorticoid system during black raspberry mediated oral cancer chemoprevention

Recent reports suggest that glucocorticoids (GCs), which can be synthesized in the oral mucosa, play an important role in cancer development. Therefore, the objectives of this study were to characterize the role of the oral GC system in oral cancer, and determine the effect of black raspberry (BRB) administration on GC modulation during oral cancer chemoprevention. We determined the expression of GC enzymes in various oral cancer cell lines, and investigated the role of the GC inactivating enzyme HSD11B2 on CAL27 oral cancer cells using siRNA mediated knockdown approaches. Using two in vivo models of oral carcinogenesis with 4-nitroquinoline-1-oxide (4NQO) carcinogen on C57Bl/6 mice and F344 rats, we determined the effect of BRB on GC modulation during HNSCC chemoprevention. Our results demonstrate that HSD11B2, which inactivates cortisol to cortisone, is downregulated during oral carcinogenesis in clinical and experimental models. Knockdown of HSD11B2 in oral cancer cells promotes cellular proliferation, invasion and expression of angiogenic biomarkers EGFR and VEGFA. An ethanol extract of BRB increased HSD11B2 expression on oral cancer cells. Dietary administration of 5% BRB increased Hsd11b2 gene and protein expression and reduced the active GC, corticosterone, in cancer-induced mouse tongues. Our results demonstrate that the oral GC system is modulated during oral carcinogenesis, and black raspberry administration upregulates Hsd11b2 during oral cancer chemoprevention. In conclusion, our findings challenge the use of synthetic glucocorticoids in head and neck cancer, and support the use of natural product alternatives that potentially modulate GC metabolism in a manner that supports oral cancer chemoprevention.

Stress hormones promote DNA damage in human oral keratinocytes

Chronic stress increases the systemic levels of stress hormones norepinephrine and cortisol. As well as tobacco-specific carcinogen NNK (4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone), they can induce expressive DNA damage contributing to the cancer development. However, it is unknown whether stress hormones have genotoxic effects in oral keratinocytes. This study investigated the effects of stress hormones on DNA damage in a human oral keratinocyte cell line (NOK-SI). NOK-SI cells stimulated with norepinephrine or cortisol showed higher DNA damage compared to untreated cells. Norepinephrine-induced DNA damage was reversed by pre-treatment with beta-adrenergic blocker propranolol. Cells treated with NNK combined to norepinephrine displayed reduced levels of caspases 3 and 7. Cortisol also reduced the activity of pro-apoptotic enzymes. NNK or norepinephrine promoted single-strand breaks and alkali-label side breaks in the DNA of NOK-SI cells. Pre-treatment of cells with propranolol abolished these effects. Carcinogen NNK in the presence or absence of cortisol also induced DNA damage of these cells. The genotoxic effects of cortisol alone and hormone combined with NNK were blocked partially and totally, respectively, by the glucocorticoid receptor antagonist RU486. DNA damage promoted by NNK or cortisol and carcinogen combined to the hormone led to intracellular γH2AX accumulation. The effects caused by NNK and cortisol were reversed by propranolol and glucocorticoid receptor antagonist RU486, respectively. Propranolol inhibited the oxidation of basis induced by NNK in the presence of DNA-formamidopyrimidine glycosylase. DNA breaks induced by norepinephrine in the presence or absence of NNK resulted in higher 8OHdG cellular levels. This effect was also induced through beta-adrenergic receptors. Together, these findings indicate that stress hormones induce DNA damage of oral keratinocytes and could contribute to oral carcinogenesis.

Glucocorticoid receptor triggers a reversible drug-tolerant dormancy state with acquired therapeutic vulnerabilities in lung cancer

The glucocorticoid receptor (GR) regulates gene expression, governing aspects of homeostasis, but is also involved in cancer. Pharmacological GR activation is frequently used to alleviate therapy-related side-effects. While prior studies have shown GR activation might also have anti-proliferative action on tumours, the underpinnings of glucocorticoid action and its direct effectors in non-lymphoid solid cancers remain elusive. Here, we study the mechanisms of glucocorticoid response, focusing on lung cancer. We show that GR activation induces reversible cancer cell dormancy characterised by anticancer drug tolerance, and activation of growth factor survival signalling accompanied by vulnerability to inhibitors. GR-induced dormancy is dependent on a single GR-target gene, CDKN1C, regulated through chromatin looping of a GR-occupied upstream distal enhancer in a SWI/SNF-dependent fashion. These insights illustrate the importance of GR signalling in non-lymphoid solid cancer biology, particularly in lung cancer, and warrant caution for use of glucocorticoids in treatment of anticancer therapy related side-effects.

Systems Biomedicine of Primary and Metastatic Colorectal Cancer Reveals Potential Therapeutic Targets

Colorectal cancer (CRC) is one of the major causes of cancer deaths across the world. Patients' survival at time of diagnosis depends mainly on stage of the tumor. Therefore, understanding the molecular mechanisms from low-grade to high-grade stages of cancer that lead to cellular migration from one tissue/organ to another tissue/organ is essential for implementing therapeutic approaches. To this end, we performed a unique meta-analysis flowchart by identifying differentially expressed genes (DEGs) between normal, primary (primary sites), and metastatic samples (Colorectal metastatic lesions in liver and lung) in some Test datasets. DEGs were employed to construct a protein-protein interaction (PPI) network. A smaller network containing 39 DEGs was then extracted from the PPI network whose nodes expression induction or suppression alone or in combination with each other would inhibit tumor progression or metastasis. These DEGs were then verified by gene expression profiling, survival analysis, and multiple Validation datasets. We suggested for the first time that downregulation of mitochondrial genes, including ETHE1, SQOR, TST, and GPX3, would help colorectal cancer cells to produce more energy under hypoxic conditions through mechanisms that are different from "Warburg Effect". Augmentation of given antioxidants and repression of P4HA1 and COL1A2 genes could be a choice of CRC treatment. Moreover, promoting active GSK-3β together with expression control of EIF2B would prevent EMT. We also proposed that OAS1 expression enhancement can induce the anti-cancer effects of interferon-gamma, while suppression of CTSH hinders formation of focal adhesions. ATF5 expression suppression sensitizes cancer cells to anchorage-dependent death signals, while LGALS4 induction recovers cell-cell junctions. These inhibitions and inductions would be another combinatory mechanism that inhibits EMT and cell migration. Furthermore, expression inhibition of TMPO, TOP2A, RFC3, GINS1, and CKS2 genes could prevent tumor growth. Besides, TRIB3 suppression would be a promising target for anti-angiogenic therapy. SORD is a poorly studied enzyme in cancer, found to be upregulated in CRC. Finally, TMEM131 and DARS genes were identified in this study whose roles have never been interrogated in any kind of cancer, neither as a biomarker nor curative target. All the mentioned mechanisms must be further validated by experimental wet-lab techniques.

Impact of cholesterol-pathways on breast cancer development, a metabolic landscape

ApoB-lipoproteins and their components modulate intracellular metabolism and have been associated with the development of neoplastic phenomena, such as proliferation, anchorage-independent growth, epithelial-mesenchymal transition, and cancer invasion. In cancer cells, the modulation of targets that regulate cholesterol metabolism, such as synthesis de novo, endocytosis, and oxidation, are contributing factors to cancer development. While mechanisms associated with sterol regulatory element-binding protein 2 (SREBP-2)/mevalonate, the low-density lipoprotein receptor (LDL-R) and liver X receptor (LXR) have been linked with tumor growth; metabolites derived from cholesterol-oxidation, such as oxysterols and epoxy-cholesterols, also have been described as tumor processes-inducers. From this notion, we perform an analysis of the role of lipoproteins, their association with intracellular cholesterol metabolism, and the impact of these conditions on breast cancer development, mechanisms that can be shared during atherogenesis promoted mainly by LDL. Pathways connecting plasma dyslipidemias in conjunction with the effect of cholesterol-derived metabolites on intracellular mechanisms and cellular plasticity phenomena could provide new approaches to elucidate the triggering factors of carcinogenesis, conditions that could be considered in the development of new therapeutic approaches.

Glucocorticoid Receptor: A Multifaceted Actor in Breast Cancer

Breast cancer (BC) is one of the most common cancers in women worldwide. Even though the role of estrogen receptor alpha (ERα) is extensively documented in the development of breast tumors, other members of the nuclear receptor family have emerged as important players. Synthetic glucocorticoids (GCs) such as dexamethasone (dex) are commonly used in BC for their antiemetic, anti-inflammatory, as well as energy and appetite stimulating properties, and to manage the side effects of chemotherapy. However, dex triggers different effects depending on the BC subtype. The glucocorticoid receptor (GR) is also an important marker in BC, as high GR expression is correlated with a poor and good prognosis in ERα-negative and ERα-positive BCs, respectively. Indeed, though it drives the expression of pro-tumorigenic genes in ERα-negative BCs and is involved in resistance to chemotherapy and metastasis formation, dex inhibits estrogen-mediated cell proliferation in ERα-positive BCs. Recently, a new natural ligand for GR called OCDO was identified. OCDO is a cholesterol metabolite with oncogenic properties, triggering mammary cell proliferation in vitro and in vivo. In this review, we summarize recent data on GR signaling and its involvement in tumoral breast tissue, via its different ligands.

Comprehensive analysis of regulation of DNA methyltransferase isoforms in human breast tumors

Significant reprogramming of epigenome is widely described during pathogenesis of breast cancer. Transformation of normal cell to hyperplastic cell and to neoplastic phenotype is associated with aberrant DNA (de)methylation, which, through promoter and enhancer methylation changes, activates oncogenes and silence tumor suppressor genes in variety of tumors including breast. DNA methylation, one of the major epigenetic mechanisms is catalyzed by evolutionarily conserved isoforms namely, DNMT1, DNMT3A and DNMT3B in humans. Over the years, studies have demonstrated intricate and complex regulation of DNMT isoforms at transcriptional, translational and post-translational levels. The recent findings of allosteric regulation of DNMT isoforms and regulation by other interacting chromatin modifying proteins emphasizes functional integrity and their contribution for the development of breast cancer and progression. DNMT isoforms are regulated by several intrinsic and extrinsic parameters. In the present review, we have extensively performed bioinformatics analysis of expression of DNMT isoforms along with their transcriptional and post-transcriptional regulators such as transcription factors, interacting proteins, hormones, cytokines and dietary elements along with their significance during pathogenesis of breast tumors. Our review manuscript provides a comprehensive understanding of key factors regulating DNMT isoforms in breast tumor pathology and documents unsolved issues.

Prognostic Significance of Glucocorticoid Receptor Expression in Cancer: A Systematic Review and Meta-Analysis

Simple Summary

In solid tumours, emerging evidence indicates that signalling through the glucocorticoid receptor (GR) can encourage the growth and spread of tumours and so drugs targeting this receptor are in development for use in cancer treatment. For these reasons, GR may be useful in anticipating a patient’s outcome upon their cancer diagnosis or to predict their tumours response to drugs targeting this receptor. In this review we aim to ascertain whether GR expression in tumours affects cancer patient survival. Overall, GR expression did not affect patient survival when assessing all cancer types. However, we found that in certain cancer subtypes such as gynaecological cancers (endometrial and ovarian) and early stage, untreated triple negative breast cancers, high GR expression is linked with cancer progression and therefore a poorer patient prognosis. Further studies are needed to uncover the exact role of GR in specific tumour (sub)types in order to provide the correct patients with GR targeting therapies.

Abstract

In solid malignancies, the glucocorticoid receptor (GR) signalling axis is associated with tumour progression and GR antagonists are in clinical development. Therefore, GR expression may be a useful potential prognostic or predictive biomarker for GR antagonist therapy in cancer. The aim of this review is to investigate if GR expression in tumours is predictive of overall survival or progression free survival. Twenty-five studies were identified through systematic searches of three databases and a meta-analysis conducted using a random effects model, quantifying statistical heterogeneity. Subgroup analysis was conducted for cancer types and publication bias was assessed via funnel plots. There was high heterogeneity in meta-analysis of the studies in all cancer types, which found no association between high GR expression with overall survival (pooled unadjusted HR 1.16, 95% CI (0.89–1.50), n = 2814; pooled adjusted HR 1.02, 95% CI (0.77–1.37), n = 2355) or progression-free survival (pooled unadjusted HR 1.12, 95% CI (0.88–1.42), n = 3365; pooled adjusted HR 1.04, 95% CI (0.6–1.81), n = 582) across all cancer types. However, subgroup meta-analyses showed that high GR expression in gynaecological cancers (endometrial and ovarian) (unadjusted HR 1.83, 95% CI (1.31–2.56), n = 664) and early stage, untreated triple negative breast cancers (TNBCs) (unadjusted HR 1.73, 95% CI (1.35–2.23), n = 687) is associated with disease progression. GR expression in late stage, chemotherapy treated TNBC was not prognostic (unadjusted HR 0.76, 95% CI (0.44, 1.32), n = 287). In conclusion, high GR expression is associated with an increased risk of disease progression in gynaecological and early stage, untreated TNBC. Additional studies are required to elucidate the tumour specific function of the GR receptor in order to ensure GR antagonists target the correct patient groups.

A bird's eye view of the advanced approaches and strategies for overshadowing triple negative breast cancer

Triple negative breast cancer (TNBC) is one of the most aggressive form of breast cancer. It is characterized by the absence of estrogen, progesterone and human epidermal growth factor receptors. The main issue with TNBC is that it exhibits poor prognosis, high risk of relapse, short progression-free survival and low overall survival in patients. This is because the conventional therapy used for managing TNBC has issues pertaining to poor bioavailability, lower cellular uptake, increased off-target effects and development of resistance. To overcome such pitfalls, several other approaches are explored. In this context, the present manuscript showcases three of the most widely used approaches which are (i) nanotechnology-based approach; (ii) gene therapy approach and (iii) Phytochemical-based approach. The ultimate focus is to present and explain the insightful reports based on these approaches. Further, the review also expounds on the identified molecular targets and novel targeting ligands which are explored for managing TNBC effectively. Thus, in a nutshell, the review tries to highlight these existing treatment approaches which might inspire for future development of novel therapies with a potential of overshadowing TNBC.

Glucocorticoid receptor-IRS-1 axis controls EMT and the metastasis of breast cancers

Glucocorticoid receptor (GR) is involved in the transcriptional regulation of genes that are important for various biological functions, including tumor growth and metastatic progression. However, the cellular and biological effects of GR remain poorly understood. Here, we investigated the role of GR and its underlying mechanism in mediating breast cancer cell survival and metastasis. We observed that the GR levels were increased in drug-resistant breast cancer cells and in metastatic breast cancer samples. GR promoted tumor cell invasion and lung metastasis in vivo. The GR expression levels were negatively correlated with the survival rates of breast cancer patients. Both ectopic expression and knockdown of GR revealed that GR is a strong inducer of epithelial-to-mesenchymal transition (EMT), which is consistent with its effects on cell survival and metastasis. GR suppressed the expression of insulin receptor substrate 1 (IRS-1) by acting as an IRS-1 transcriptional repressor. In addition, GR has an opposite effect on the expression levels of IRS-2, indicating that GR is able to differentially regulate the IRS-1 and IRS-2 expression. The cellular and biological effects elicited by GR were consistent with the reduced levels of IRS-1 observed in cancer cells, and GR-mediated IRS-1 suppression activated the ERK2 MAP kinase pathway, which is required for GR-mediated EMT. Taken together, our results indicate that GR–IRS-1 signaling axis plays an essential role in regulating the survival, invasion, and metastasis of breast cancer cells.

Differential Glucocorticoid-Dependent Regulation and Function of the ERRFI1 Gene in Triple-Negative Breast Cancer

Glucocorticoids (GCs; eg, hydrocortisone [CORT]) are routinely used as chemotherapeutic, anti-emetic, and palliative agents in breast cancer (BCa) therapy. The effects of GC signaling on BCa progression, however, remain a contentious topic as GC treatment seems to be beneficial for receptor-positive subtypes but elicits unfavorable responses in triple-negative BCa (TNBC). The mechanistic basis for these conflicting effects of GC in BCa is poorly understood. In this study, we sought to decipher the molecular mechanisms that govern the GC-dependent induction of the tumor suppressor ERRFI1 gene, an inhibitor of epidermal growth factor receptor (EGFR) signaling, and characterize the role of the GC-ERRFI1 regulatory axis in TNBC. Treatment of TNBC cell lines with a protein synthesis inhibitor or GC receptor (GR) antagonist followed by gene expression analysis suggests that ERRFI1 is a direct GR target. Using in silico analysis coupled with enhancer-reporter assays, we identified a putative ERRFI1 enhancer that supports CORT-dependent transactivation. In orthogonal assays for cell proliferation, survival, migration, and apoptosis, CORT mostly facilitated an oncogenic phenotype regardless of malignancy status. Lentiviral knockdown and overexpression of ERRFI1 showed that the CORT-enhanced oncogenic phenotype is restricted by ERRFI1 in the normal breast epithelial model MCF10A and to a lesser degree in the metastatic TNBC line MDA-MB-468. Conversely, ERRFI1 conferred pro-tumorigenic effects in the highly metastatic TNBC model MDA-MB-231. Taken together, our findings suggest that the progressive loss of the GC-dependent regulation and anti-tumorigenic function of ERRFI1 influences BCa progression and may contribute to the unfavorable effects of GC therapy in TNBC.

Occurrence of Immunoglobulin G4-related Disease during Chemotherapy for Advanced Breast Cancer

Immunoglobulin G4-related disease (IgG4-RD) is defined as an inflammatory lymphoproliferative disorder. The relationship between malignancies and IgG4-RD remains unclear. We herein present a case of IgG4-RD that occurred during chemotherapy for advanced breast cancer. In this case, it was challenging to determine which of these diseases was responsible for the patient's mediastinal lymphadenopathy. Lymphadenopathy with IgG4-RD was diagnosed by assessing the reactivity to corticosteroids, which were used as premedication in chemotherapy, over time. The administration of prednisolone, which was initiated to treat active IgG4-RD, led to stable systemic therapy for malignancy. It is imperative to assess the disease activity and consider each treatment.

90 YEARS OF PROGESTERONE: Steroid receptors as MAPK signaling sensors in breast cancer: let the fates decide

Steroid hormone receptors (SRs) are classically defined as ligand-activated transcription factors that function as master regulators of gene programs important for a wide range of processes governing adult physiology, development, and cell or tissue homeostasis. A second function of SRs includes the ability to activate cytoplasmic signaling pathways. Estrogen (ER), androgen (AR), and progesterone (PR) receptors bind directly to membrane-associated signaling molecules including mitogenic protein kinases (i.e. c-SRC and AKT), G-proteins, and ion channels to mediate context-dependent actions via rapid activation of downstream signaling pathways. In addition to making direct contact with diverse signaling molecules, SRs are further fully integrated with signaling pathways by virtue of their N-terminal phosphorylation sites that act as regulatory hot-spots capable of sensing the signaling milieu. In particular, ER, AR, PR, and closely related glucocorticoid receptors (GR) share the property of accepting (i.e. sensing) ligand-independent phosphorylation events by proline-directed kinases in the MAPK and CDK families. These signaling inputs act as a 'second ligand' that dramatically impacts cell fate. In the face of drugs that reliably target SR ligand-binding domains to block uncontrolled cancer growth, ligand-independent post-translational modifications guide changes in cell fate that confer increased survival, EMT, migration/invasion, stemness properties, and therapy resistance of non-proliferating SR+ cancer cell subpopulations. The focus of this review is on MAPK pathways in the regulation of SR+ cancer cell fate. MAPK-dependent phosphorylation of PR (Ser294) and GR (Ser134) will primarily be discussed in light of the need to target changes in breast cancer cell fate as part of modernized combination therapies.

Glucocorticoid Receptor Expression Predicts Good Outcome in response to Taxane-Free, Anthracycline-Based Therapy in Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) is a poor outcome subset of breast cancers characterised by the lack of expression of ER α, PR, and HER2 amplification. It is a heterogeneous group of cancers which fail to derive benefit from modern, more targeted treatments such as Tamoxifen and Herceptin. Current standard of care (SoC) is cytotoxic chemotherapy, which is effective for some patients, with other patients deriving little/no benefit and lacking alternative treatments. This study has identified the glucocorticoid receptor (GR) as a potential predictive biomarker of response to anthracycline-based chemotherapy in triple negative breast cancer (TNBC). GR gene expression levels in patient samples were analysed through publicly available microarray datasets as well as protein expression through immunohistochemistry (IHC) and correlated with clinical/pathological outcomes, including survival. While the results confirmed previous observations that high GR expression is associated with poor outcome in response to taxane-based chemotherapy, this study shows for the first time that high GR expression is associated with improved outcomes in the context of anthracycline-based chemotherapy. GR therefore has the potential to be used as a predictive biomarker to guide treatment choices and ensure that patients derive the greatest benefit from first line treatment, avoiding unnecessary costs, side effects, and disease progression.

Glucocorticoid receptors are required effectors of TGFβ1-induced p38 MAPK signaling to advanced cancer phenotypes in triple-negative breast cancer

BACKGROUND

Altered signaling pathways typify breast cancer and serve as direct inputs to steroid hormone receptor sensors. We previously reported that phospho-Ser134-GR (pS134-GR) species are elevated in triple-negative breast cancer (TNBC) and cooperate with hypoxia-inducible factors, providing a novel avenue for activation of GR in response to local or cellular stress.

METHODS

We probed GR regulation by factors (cytokines, growth factors) that are rich within the tumor microenvironment (TME). TNBC cells harboring endogenous wild-type (wt) or S134A-GR species were created by CRISPR/Cas knock-in and subjected to transwell migration, invasion, soft-agar colony formation, and tumorsphere assays. RNA-seq was employed to identify pS134-GR target genes that are regulated both basally (intrinsic) or by TGFβ1 in the absence of exogenously added GR ligands. Regulation of selected basal and TGFβ1-induced pS134-GR target genes was validated by qRT-PCR and chromatin immunoprecipitation assays. Bioinformatics tools were used to probe public data sets for expression of pS134-GR 24-gene signatures.

RESULTS

In the absence of GR ligands, GR is transcriptionally activated via p38-dependent phosphorylation of Ser134 as a mechanism of homeostatic stress-sensing and regulated upon exposure of TNBC cells to TME-derived agents. The ligand-independent pS134-GR transcriptome encompasses TGFβ1 and MAPK signaling gene sets associated with TNBC cell survival and migration/invasion. Accordingly, pS134-GR was essential for TNBC cell anchorage-independent growth in soft-agar, migration, invasion, and tumorsphere formation, an in vitro readout of cancer stemness properties. Both pS134-GR and expression of the MAPK-scaffolding molecule 14-3-3ζ were essential for a functionally intact p38 MAPK signaling pathway downstream of MAP3K5/ASK1, indicative of a feedforward signaling loop wherein self-perpetuated GR phosphorylation enables cancer cell autonomy. A 24-gene pS134-GR-dependent signature induced by TGFβ1 predicts shortened overall survival in breast cancer patients.

CONCLUSIONS

Phospho-S134-GR is a critical downstream effector of p38 MAPK signaling and TNBC migration/invasion, survival, and stemness properties. Our studies define a ligand-independent role for GR as a homeostatic "sensor" of intrinsic stimuli as well as extrinsic factors rich within the TME (TGFβ1) that enable potent activation of the p38 MAPK stress-sensing pathway and nominate pS134-GR as a therapeutic target in aggressive TNBC.

Consideration of Ketogenic Metabolic Therapy as a Complementary or Alternative Approach for Managing Breast Cancer

Breast cancer remains as a significant cause of morbidity and mortality in women. Ultrastructural and biochemical evidence from breast biopsy tissue and cancer cells shows mitochondrial abnormalities that are incompatible with energy production through oxidative phosphorylation (OxPhos). Consequently, breast cancer, like most cancers, will become more reliant on substrate level phosphorylation (fermentation) than on oxidative phosphorylation (OxPhos) for growth consistent with the mitochondrial metabolic theory of cancer. Glucose and glutamine are the prime fermentable fuels that underlie therapy resistance and drive breast cancer growth through substrate level phosphorylation (SLP) in both the cytoplasm (Warburg effect) and the mitochondria (Q-effect), respectively. Emerging evidence indicates that ketogenic metabolic therapy (KMT) can reduce glucose availability to tumor cells while simultaneously elevating ketone bodies, a non-fermentable metabolic fuel. It is suggested that KMT would be most effective when used together with glutamine targeting. Information is reviewed for suggesting how KMT could reduce systemic inflammation and target tumor cells without causing damage to normal cells. Implementation of KMT in the clinic could improve progression free and overall survival for patients with breast cancer.

Significance of glucocorticoid signaling in triple-negative breast cancer patients: a newly revealed interaction with androgen signaling

PURPOSE

Chemotherapy is the only current effective systemic treatment for triple-negative breast cancer (TNBC) patients. Therefore, the identification of active biological pathways that could become therapeutic targets is crucial. In this study, considering the well-reported biological roles of glucocorticoid and androgen receptors (GR, AR) in TNBC, we attempted to explore the effects of glucocorticoids (GCs) on cell kinetics as well as the potential interaction between GR and AR in TNBC.

METHODS

We first explored the association between the status of GR, AR, and/or GCs-metabolizing enzymes such as 11β-hydroxysteroid dehydrogenase (11βHSD) 1 and 2 and the clinicopathological variables of the TNBC patients. Thereafter, we also studied the effects of dexamethasone (DEX) with/without dihydrotestosterone (DHT) on TNBC cell lines by assessing the cell proliferation, migration and GC response genes at the transcriptional level.

RESULTS

GR positivity in carcinoma cells was significantly associated with adverse clinical outcome of the patients and AR positivity was significantly associated with lower histological grade and Ki-67 labeling index of the cases examined. In particular, AR positivity was significantly associated with decreased risks of developing recurrence in GR-positive TNBC patients. The subsequent in vitro studies revealed that DEX-promoted cell migration was inhibited by the co-treatment with DHT in GR/AR double-positive HCC38 cells. In addition, DHT inhibited the DEX-increased serum and glucocorticoid-regulated kinase-1 (SGK1) mRNA expression.

CONCLUSION

This is the first study to reveal that the interaction of GR and AR did influence the clinical outcome of TNBC patients and GCs induced cell migration in TNBC cells.

Stress and drug resistance in cancer

Patients diagnosed with cancer often undergo considerable psychological distress, and the induction of the psychological stress response has been linked with a poor response to chemotherapy. The psychological stress response is mediated by fluctuations of the hormones glucocorticoids (GCs) and catecholamines. Binding to their respective receptors, GCs and the catecholamines adrenaline/noradrenaline are responsible for signalling a wide range of processes involved in cell survival, cell cycle and immune function. Synthetic GCs are also often prescribed as co-medication alongside chemotherapy, and increasing evidence suggests that GCs may induce chemoresistance in multiple cancer types. In this review, we bring together evidence linking psychological stress hormone signalling with resistance to chemo- and immune therapies, as well as mechanistic evidence regarding the effects of exogenous stress hormones on the efficacy of chemotherapies.

SGK1 Attenuates Oxidative Stress-Induced Renal Tubular Epithelial Cell Injury by Regulating Mitochondrial Function

Mitochondrial dysfunction has been implicated in the early stages or progression of many renal diseases. Improving mitochondrial function and homeostasis has the potential to protect renal function. Serum- and glucocorticoid-induced kinase 1 (SGK1) is known to regulate various cellular processes, including cell survival. In this study, we intend to demonstrate the effect and molecular mechanisms of SGK1 in renal tubular cells upon oxidative stress injury and to determine whether regulation of mitochondrial function is implicated in this process. HK-2 cells were exposed to H₂O₂, and cell viability and apoptosis were dynamically detected by the CCK-8 assay and annexin-V/PI staining. The concentrations of cellular reactive oxygen species (ROS) and adenosine triphosphate (ATP) and the expression of the SGK1/GSK3β/PGC-1α signaling pathway were analyzed by flow cytometry or western blot. In addition, shRNA targeting SGK1 and SB216763 were added into the culture medium before H₂O₂ exposure to downregulate SGK1 and GSK3β, respectively. Cell viability and mitochondrial functions, including mitochondrial membrane potential (Δψm), Cytochrome C release, mtDNA copy number, and mitochondrial biogenesis, were examined. Protein levels and SGK1 activation were significantly stimulated by H₂O₂ exposure. HK-2 cells with SGK1 inhibition were much more sensitive to H₂O₂-induced oxidative stress injury than control group cells, as they exhibited increased apoptotic cell death and mitochondrial dysfunction involving the deterioration of cellular ATP production, ROS accumulation, mitochondrial membrane potential reduction, and release of Cytochrome C into the cytoplasm. Studies on SGK1 knockdown also indicated that SGK1 is required for the induction of proteins associated with mitochondrial biogenesis, including PGC-1α, NRF-1, and TFAM. Moreover, the deleterious effects of SGK1 suppression on cell apoptosis and mitochondrial function, including mitochondrial biogenesis, were related to the phosphorylation of GSK3β and partially reversed by SB216763 treatment. H₂O₂ leads to SGK1 overexpression in HK-2 cells, which protects human renal tubule cells from oxidative stress injury by improving mitochondrial function and inactivating GSK3β.

Reduced inflammatory state promotes reinnervation of endometriotic-like lesions in TNFRp55 deficient mice

Endometriosis is a chronic gynecological disease, characterized by growth of endometrial tissue in ectopic sites due to alteration of peritoneal homeostasis and deregulation of apoptosis. Here we have examined whether TNFRp55 deficiency modulates the pro-inflammatory state and the reinnervation of endometriotic-like lesions in mice. Two-month-old female C57BL/6 mice, eight wild type (WT) and eight TNFRp55-/- (KO) were used in the study. Endometriotic-like lesions were induced experimentally. The right uterine horn was removed from the animal, divided longitudinally, cut in three square pieces and sutured to the intestine mesentery. After 4 weeks, the lesions and the peritoneal fluid were collected. The level of TNFα in the peritoneal fluid was evaluated by enzyme-linked immunosorbent assay (EIA). The expressions of COX2, GRα and GRβ were evaluated in the lesions by western blot and immunohistochemistry. β-III TUBULIN, BDNF and NGF protein concentrations were evaluated in the lesions by western blot. Gene expression of Pgp 9.5, SP and Th was analyzed by RT-PCR, whereas relative concentrations of TRKA, NTRp75, phosphorylated NFκB (pNFκB) and total NFκB in lesions were measured by EIA. Compared with the WT group, the KO mice showed lower TNFα levels in the peritoneal fluid and lower numbers of COX2 immunoreactive cells along with increased expression of GRα, β-III TUBULIN, Pgp 9.5, SP, Th, BDNF, NGF, NTRp75 and pNFκB in the lesions. Future histological studies will be necessary to confirm the sensory/sympathetic imbalance in the endometriotic-like lesions of the KO mice. Our results suggest that a reduced inflammatory state promotes reinnervation of endometriotic-like lesions in TNFRp55-/- mice. Chronic deregulation of TNF receptors can have serious consequences for women with advanced endometriosis.

Spinal Serum- and Glucocorticoid-Regulated Kinase 1 (SGK1) Signaling Contributes to Morphine-Induced Analgesic Tolerance in Rats

Accumulating evidence indicates that phosphorylated serum- and glucocorticoid-regulated kinase 1 (SGK1) is associated with spinal nociceptive sensitization by modulating glutamatergic N-methyl-D-aspartate receptors (NMDARs). In this study, we determined whether spinal SGK1 signaling contributes to the development of morphine analgesic tolerance. Chronic morphine administration markedly induced phosphorylation of SGK1 in the spinal dorsal horn neurons. Intrathecal injection of SGK1 inhibitor GSK-650394 reduced the development of morphine tolerance with a significant leftward shift in morphine dose-effect curve. Furthermore, spinal inhibition of SGK1 suppressed morphine-induced phosphorylation of nuclear factor kappa B (NF-κB) p65 and upregulation of NMDAR NR1 and NR2B expression in the spinal dorsal horn. In contrast, intrathecal administration of NMDAR antagonist MK-801 had no effect on the phosphorylation of SGK1 in morphine-treated rats. In addition, morphine-induced upregulation of NR2B, but not NR1, was significantly abolished by intrathecal pretreatment with PDTC, a specific NF-κB activation inhibitor. Finally, spinal delivery of SGK1 small interfering RNA exhibited similar inhibitory effects on morphine-induced tolerance, phosphorylation of NF-κB p65, as well as upregulation of NR1 and NR2B expression. Our findings demonstrate that spinal SGK1 contributes to the development of morphine tolerance by enhancing NF-κB p65/NMDAR signaling. Interfering spinal SGK1 signaling pathway could be a potential strategy for prevention of morphine tolerance in chronic pain management.

Radiation-induced glucocorticoid receptor promotes CD44+ prostate cancer stem cell growth through activation of SGK1-Wnt/β-catenin signaling

We observed cancer stem cell (CSC) population increase in radioresistant LNCaP (LNCaPR18) and C4-2 (C4-2R26) prostate cancer (PCa) cells compared with respective parental cells. Since the CD44 level increase was most significant in radioresistant PCa cells compared with parental cells among CSC markers tested, we isolated the CD44+ population from LNCaP/LNCaPR18 and C4-2/C4-2R26 cell sets via the immunomagnetic separation method and used them as CSC sources. We detected lower AR level, but higher glucocorticoid receptor (GR) level in CD44+ CSCs than CD44- non-CSCs. Higher GR level in CD44+ CSCs than CD44- cells was also detected when cells were isolated from mouse tumor tissues of LNCaPR18 cell and C4-2R26 cell-derived human xenografts and grown in culture. We then found blocking the GR signaling by adding the anti-GR agent mifepristone into the cell culture inhibited the CD44+ CSC growth while the addition of the anti-AR agent enzalutamide enhanced the CSC growth. In xenograft mouse studies in which tumors were developed from the injection of CD44+ CSCs of LNCaPR18 or C4-2R26 cell lines, retarded tumor growth in mifepristone-injected mice was observed compared with vehicle-treated mice. We next discovered the GR regulation of Wnt/β-catenin signaling pathway. We further found that the serum/glucocorticoid regulated kinase 1 (SGK1) is the GR downstream molecule that mediates Wnt/β-catenin signaling activation. Therefore, inhibition of either SGK1 or Wnt/β-catenin signaling impaired the in vitro CD44+ CSC growth. From these results, we suggest that blocking GR signaling or its downstream SGK1-Wnt/β-catenin signaling axis may suppress the radiation-induced CSC increase in PCa. KEY MESSAGES: Higher CSC population exists in radioresistant PCa cells than parental cells. Higher GR levels (and lower AR level) in CD44+ CSCs than CD44- non-CSCs. Use of anti-GR agent blocked the growth of CD44+ CSCs in in vitro/in vivo tests. GR downstream SGK1-Wnt/β-catenin signaling axis mediates the CSC increase. Targeting this signaling axis may enhance the radiotherapy efficacy in treating PCa.