Recent insights into the mechanism of glucocorticosteroid-induced apoptosis

Daily glucocorticoids promote glioblastoma growth and circadian synchrony to the host

Glioblastoma (GBM) is the most common primary brain tumor in adults with a poor prognosis despite aggressive therapy. A recent, retrospective clinical study found that administering Temozolomide in the morning increased patient overall survival by 6 months compared to evening. Here, we tested the hypothesis that daily host signaling regulates tumor growth and synchronizes circadian rhythms in GBM. We found daily Dexamethasone promoted or suppressed GBM growth depending on time of day of administration and on the clock gene, Bmal1. Blocking circadian signals, like VIP or glucocorticoids, dramatically slowed GBM growth and disease progression. Finally, mouse and human GBM models have intrinsic circadian rhythms in clock gene expression in vitro and in vivo that entrain to the host through glucocorticoid signaling, regardless of tumor type or host immune status. We conclude that GBM entrains to the circadian circuit of the brain, which modulates its growth through clockcontrolled cues, like glucocorticoids.

Static electric field exposure decreases white blood cell count in peripheral blood through activating hypothalamic-pituitary-adrenal axis

With the development of ultra-high-voltage (UHV) direct-current (DC) transmission, the health risk from the static electric field (SEF) generated by UHV DC transmission lines has drawn public attention. To investigate the effect of SEF exposure on white blood cell (WBC) count, mice were exposed to 56.3 kV/m SEF. Results revealed that total WBC count and lymphocyte count significantly decreased and serum levels of corticotropin-releasing hormone, adrenocorticotropic hormone and corticosterone (CORT) significantly increased after the exposure of 7d and 14d. All indices above recovered after the exposure of 21d. Analysis showed that the exposure of 7d and 14d could activate hypothalamic-pituitary-adrenal (HPA) axis. The increased CORT could bind to the glucocorticoid receptor (GR) in lymphocytes, and then promote the migration and apoptosis of lymphocytes. After the exposure of 21d, the magnitude of HPA axis activation declined through CORT-mediated negative feedback and the regulation of stress-related neural circuitry, so WBC count recovered.

Expression of NEAT1 can be used as a predictor for Dex resistance in multiple myeloma patients

OBJECTIVE

Multiple myeloma is a heterogeneous disorder and the intratumor genetic heterogeneity contributes to emergency of drug resistance. Dexamethasone has been used clinically for decades for MM. Nevertheless, their use is severely hampered by the risk of developing side effects and the occurrence of Dex resistance. LncRNA NEAT1 plays a oncogenic role and participates in drug resistance in many solid tumors. Therefore, we investigated a potential usefulness of this molecular as a biomarker for diagnosis of MM and possible correlations of NEAT1 expression with drug resistance and prognosis.

METHODS

Bone marrow and peripheral blood mononuclear cells samples were collected from 60 newly diagnosed MM patients. The expression of NEAT1expression level were detected by quantitative real-time PCR analyses. The relationship about the expression levels of lncRNA with other clinical and cytogenetic features was analyzed. In addition, we measured to analysis the correlation between the expression of NEAT1 and Dex resistance in MM patients.

RESULTS

It was found that the expression of NEAT1 is significantly higher in multiple myeloma patients compared to controls and does not change with other clinical features and cytogenetic features. We further discovered that overexpression of NEAT1 was associated with Dex resistance and a poor prognosis in MM patients.

CONCLUSION

LncRNA NEAT1 has a significant value that might act as a promoting factor in the development of MM and may be severed as a diagnostic factor in MM. NEAT1 invovled in Dex resistance, which provide a new interpretation during the chemotherapy for MM.

The combination of chronic stress and smoke exacerbated depression-like changes and lung cancer factor expression in A/J mice: Involve inflammation and BDNF dysfunction

OBJECTIVE

Depression is positively correlated with the high incidence and low survival rate of cancers, while more cancer patients suffer depression. However, the interaction between depression and cancer, and possible underline mechanisms are unclear.

METHODS

Chronic unpredictable mild stress (CUMS) was used to induce depression, and smoke to induce lung cancer in lung cancer vulnerable AJ mice. After 8 weeks, sucrose preference and forced swimming behaviors were tested. Blood corticosterone concentration, and levels of cytokines, lung cancer-related factors, brain-derived neurotrophic factor (BDNF) and apoptosis-related factors in the lung, amygdala and hippocampus were measured.

RESULTS

Compared to control group, CUMS or smoke decreased sucrose consumption and increased immobility time, which were deteriorated by stress+smoke. CUMS, smoke or both combination decreased mononuclear viability and lung TNF-α concentration, increased serum corticosterone and lung interleukin (IL)-1, IL-2, IL-6, IL-8, IL-10, IL-12 and HSP-90α concentrations. Furthermore, stress+smoke caused more increase in corticosterone and IL-10, but decreased TNF-α. In parallel, in the lung, Bcl-2/Bax and lung cancer-related factors CDK1, CDC20, P38α etc were significantly increased in stress+smoke group. Moreover, CUMS decreased BDNF, while CUMS or smoke increased TrkB and P75 concentrations, which were exacerbated by stress+smoke. In the amygdala, except for CUMS largely increased Bax/Bcl-2 and decreased TrkB, each single factor decreased BDNF and IL-10, but increased P75, IL-1β, IL-12, TNF-α concentrations. Changes in Bax/Bcl-2, IL-10 and TNF-α were further aggravated by the combination. In the hippocampus, except for CUMS largely increased P75 concentration, each single factor significantly increased Bax/Bcl-2 ratio, IL-1β and TNF-α, but decreased BDNF, TrkB and IL-10 concentrations. Changes in Bax, Bax/Bcl-2, IL-10 and TNF-α were further aggravated by the combination.

CONCLUSION

These results suggest that a synergy between CUMS and smoke exposure could promote the development of depression and lung cancer, through CUMS increased the risk of cancer occurrence, and conversely lung cancer inducer smoke exposure deteriorated depressive symptoms.

Evaluation of Tumor Grade and Proliferation Indices before and after Short-Course Anti-Inflammatory Prednisone Therapy in Canine Cutaneous Mast Cell Tumors: A Pilot Study

Glucocorticoid administration is a common clinical practice that attempts to decrease the inflammation associated with and improve the resectability of canine mast cell tumors (MCTs). However, the impact of neoadjuvant glucocorticoids on the histological features and proliferation indices of canine MCTs is unknown. The objective of this study was to evaluate changes in tumor grade, mitotic count, Ki67, AgNOR, and AgNORxKi67 scores following short-course anti-inflammatory neoadjuvant prednisone in canine patients with MCTs. This was a prospective single-arm pilot study. Client-owned dogs with treatment-naïve cytologically confirmed MCTs were enrolled. Patients underwent an initial incisional biopsy followed by a 10–14-day course of anti-inflammatory prednisone and surgical resection. All histological samples were randomized, masked, and evaluated by a single pathologist. Unstained paired pre- and post-treatment samples were submitted to a commercial laboratory for Ki67 and AgNOR immunohistochemical analysis. There were 11 dogs enrolled with 11 tumors. There were no statistical differences between the pre- and post-treatment histological parameters of mitotic index, Ki67, AgNOR, or Ki67xAgNOR. There were no clinically significant alterations between pre-treatment and post-treatment in the assignment of tumor grades. A short course of anti-inflammatory prednisone does not appear to alter the histological parameters that affect grade determination or significantly alter the proliferation indices in canine MCTs.

CASPorter: A Novel Inducible Human CASP1/NALP3/ASC Inflammasome Biosensor

Background

Following our 2015 elucidation of the CASP1/NALP3 inflammasome mechanism of glucocorticoid (GC)-resistance in pediatric acute lymphoblastic leukemia (ALL) patients, we engineered a cell-based CASP1/NALP3 reporter system suitable for high-throughput screening (HTS) of small molecule libraries, with the purpose of identifying compounds capable of inhibiting the CASP1/NALP3 inflammasome and synergizing with GC drugs for the treatment of GC-resistant ALL patients and various autoinflammatory diseases.

Methods

A Dox-controlled system was utilized to induce the expression of the ASC transgene in HEK293 cells while simultaneously overexpressing NLRP3 and CASP1. ASC/CASP1/NALP3 inflammasome complex formation was confirmed by co-immunoprecipitation (co-IP) experiments. Next, a LV fluorescence-based biosensor (CASPorter) was transduced in the HEK293-iASC-NLRP3/CASP1 cell line to monitor the real-time activation of CASP1/NALP3 inflammasome in live cells. The applicability and effectiveness of the CASPorter cell line were tested by co-treatment with Dox and four known CASP1/NLRP3 inhibitors (MCC950, Glyburide, VX-765 and VRT-043198). Inflammasome activation and inhibitions were assessed by Western blotting, fluorescence microscopy and flow cytometry (FC) methods.

Results

Dox treatment significantly induced ASC expression and increased levels of cleaved and catalytically active CASP1, co-IPs further demonstrated that CASP1 was pulled-down with NLRP3 in HEK293-iASC-NLRP3/CASP1 cells after induction of ASC by Dox treatment. In HEK293-iASC-NLRP3/CASP1-CASPorter cell system, cleavage of the CASP1 consensus site (YVAD) in the CASPorter protein after Dox treatment causing excitation/emission of green fluorescence and the 71% GFP+ cell population increase quantified by FC (78.1% vs 6.90%). Dox-induced activation of the NLRP3 inflammasome was dose-dependently inhibited by Dox co-treatment with four known CASP1/NLRP3 inhibitors.

Conclusion

We have established a cell-based CASP1/NLRP3 inflammasome model, utilizing a fluorescence biosensor as readout for qualitatively observing and quantitatively determining the activation of caspase 1 and NLRP3 inflammasomes in living cells and easily define the inhibitory effect of inhibitors with high efficacy.

Survival time for dogs with previously untreated, peripheral nodal, intermediate- or large-cell lymphoma treated with prednisone alone: the Canine Lymphoma Steroid Only trial

OBJECTIVE

To evaluate survival times for dogs with previously untreated, peripheral nodal, intermediate- or large-cell lymphoma treated with prednisone alone.

ANIMALS

109 client-owned dogs recruited from 15 institutions in the United States.

PROCEDURES

Dogs were treated with prednisone at a dosage of 40 mg/m², PO, once daily for 7 days and at a dosage of 20 mg/m², PO, once daily thereafter. Quality of life (QOL) was assessed by owners with a visual analog scale when treatment was started (day 0), 1 and 2 weeks after treatment was started, and every 4 weeks thereafter. The primary outcome of interest was survival time as determined by the Kaplan-Meier method. Factors potentially associated with survival time were examined.

RESULTS

Median overall survival time was 50 days (95% CI, 41 to 59 days). Factors associated with survival time included substage (a vs b) and immunophenotype (B cell vs T cell). Owner-assigned QOL scores on days 0 and 14 were significantly positively correlated with survival time. When QOL score was dichotomized, dogs with day 0 or day 14 QOL scores ≥ 50 had significantly longer survival times, compared with dogs with day 0 or day 14 QOL scores < 50. No variables were predictive of long-term (> 120 days) survival.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that survival times were short for dogs with previously untreated, peripheral nodal, intermediate- or large-cell lymphoma treated with prednisone alone. Owner-perceived QOL and clinician-assigned substage were both associated with survival time. Findings provide potentially important information for clinicians to discuss with owners of dogs with lymphoma at the time treatment decisions are made.

Thymus and meat physicochemical measurements to discriminate calves treated with anabolic and therapeutic doses of dexamethasone

To preserve the Europe consumers' health, the use of glucocorticoids as growth promoters is prohibited in cattle fattening. In 2008, the Italian Ministry of Health associated to the official control a national monitoring plan based on the histological thymus analysis to identify animals illegally treated with corticosteroids. However, since corticosteroids are authorized and widely used for therapeutic purposes, it is necessary to verify whether the thymus histological test and some physicochemical traits in meat are able to discriminate doped calves from dexamethasone therapeutic treated ones. The aims of this study were (i) to establish whether the therapeutic and illicit corticosteroid treatments of calves could be differentiated through histological evaluation of thymus and by physicochemical meat traits; (ii) to identify a restricted number of physicochemical traits that could differentiate dexamethasone treated from untreated calves. Three groups of 15 calves each were included in this study: group dexamethasone therapeutic treatment treated with dexamethasone 21-phosphate disodium salt at a therapeutic dose (2 mg/kg of live weight for three consecutive days); group dexamethasone anabolic treatment orally treated with dexamethasone 21-phosphate disodium salt according to a presumed anabolic protocol (0.4 mg/day per animal for 20 days); group placebo control treated with a placebo served as control. Results demonstrated that groups could be easily discriminated by thymus microscopy as well as by two meat markers, namely, cooking loss and shear firmness or Warner-Bratzler shear force. The combination of thymus microscopic features and meat physicochemical traits could be used as a practical, economic and accurate screening strategy to discriminate between meat from illegally and therapeutically treated calves. This new reliable and simple tool could contribute to identify animals treated with dexamethasone in those countries where glucocorticoids are illegally used as growth promoters. More in general, this system could be included in the framework of official controls, and applied to verify suppliers' reliability by the meat industry.

Targeting BCL-2 with venetoclax and dexamethasone in patients with relapsed/refractory t(11;14) multiple myeloma

Venetoclax (Ven) is a selective small-molecule inhibitor of BCL-2 that exhibits antitumoral activity against MM cells with t(11;14) translocation. We evaluated the safety and efficacy of Ven and dexamethasone (VenDex) combination in patients with t(11;14) positive relapsed/refractory (R/R) multiple myeloma (MM). This open-label, multicenter study had two distinct phases (phase one [P1], phase two [P2]). Patients in both phases received VenDex (oral Ven 800 mg/day + oral Dex 40 mg [20 mg for patients ≥75 years] on days 1, 8, and 15, per 21-day cycle). The primary objective of the P1 VenDex cohort was to assess safety and pharmacokinetics. Phase two further evaluated efficacy with objective response rate (ORR) and very good partial response or better. Correlative studies explored baseline BCL2 (BCL-2) and BCL2L1 (BCL-X_L ) gene expression, cytogenetics, and recurrent somatic mutations in MM. Twenty and 31 patients in P1 and P2 with t(11;14) positive translocation received VenDex. P1/P2 patients had received a median of 3/5 lines of prior therapy, and 20%/87% were refractory to daratumumab. Predominant grade 3/4 hematological adverse events (AEs) with ≥10% occurrence included lymphopenia (20%/19%), neutropenia (15%/7%), thrombocytopenia (10%/10%), and anemia (5%/16%). At a median follow-up of 12.3/9.2 months, ORR was 60%/48%. The duration of response estimate at 12 months was 50%/61%, and the median time to progression was 12.4/10.8 months. In biomarker evaluable patients, response to VenDex was independent of concurrent del(17p) or gain(1q) and mutations in key oncogenic signaling pathways, including MAPK and NF-kB. VenDex demonstrated efficacy and manageable safety in heavily-pre-treated patients with t(11;14) R/R MM.

Overcoming Glucocorticoid Resistance in Acute Lymphoblastic Leukemia: Repurposed Drugs Can Improve the Protocol

Glucocorticoids (GCs) are a central component of multi-drug treatment protocols against T and B acute lymphoblastic leukemia (ALL), which are used intensively during the remission induction to rapidly eliminate the leukemic blasts. The primary response to GCs predicts the overall response to treatment and clinical outcome. In this review, we have critically analyzed the available data on the effects of GCs on sensitive and resistant leukemic cells, in order to reveal the mechanisms of GC resistance and how these mechanisms may determine a poor outcome in ALL. Apart of the GC resistance, associated with a decreased expression of receptors to GCs, there are several additional mechanisms, triggered by alterations of different signaling pathways, which cause the metabolic reprogramming, with an enhanced level of glycolysis and oxidative phosphorylation, apoptosis resistance, and multidrug resistance. Due to all this, the GC-resistant ALL show a poor sensitivity to conventional chemotherapeutic protocols. We propose pharmacological strategies that can trigger alternative intracellular pathways to revert or overcome GC resistance. Specifically, we focused our search on drugs, which are already approved for treatment of other diseases and demonstrated anti-ALL effects in experimental pre-clinical models. Among them are some “truly” re-purposed drugs, which have different targets in ALL as compared to other diseases: cannabidiol, which targets mitochondria and causes the mitochondrial permeability transition-driven necrosis, tamoxifen, which induces autophagy and cell death, and reverts GC resistance through the mechanisms independent of nuclear estrogen receptors (“off-target effects”), antibiotic tigecycline, which inhibits mitochondrial respiration, causing energy crisis and cell death, and some anthelmintic drugs. Additionally, we have listed compounds that show a classical mechanism of action in ALL but are not used still in treatment protocols: the BH3 mimetic venetoclax, which inhibits the anti-apoptotic protein Bcl-2, the hypomethylating agent 5-azacytidine, which restores the expression of the pro-apoptotic BIM, and compounds targeting the PI3K-Akt-mTOR axis. Accordingly, these drugs may be considered for the inclusion into chemotherapeutic protocols for GC-resistant ALL treatments.

Chronic stress decreases ornithine decarboxylase expression and protects against 1,2-dimethylhydrazine-induced colon carcinogenesis

Biological response to stress depends on the type, timing, and severity of the stressor. Acute stressful environments may positively activate molecular and cellular mechanisms to favor adaptation; however, chronic stress is often associated with detrimental health effects. Colon cancer (CC) is one of the leading causes of death associated with cancer and has been mentioned as a stress-related disease. In the present work, the effect of chronic stress on the initial phase of CC was evaluated, and special emphasis was placed on ornithine decarboxylase (ODC) expression and polyamines for their role in hyperproliferative diseases. BALB/c mice (n = 5/group) were administered the pro-carcinogen 1,2-dimethylhydrazine (DMH) for 8 weeks (20 mg/kg body weight/week) to induce colon carcinogenesis, and then exposed for 4 weeks to two physical stressors: restraint and forced-swimming. Distal colon inflammatory lesions and histomorphological changes were evaluated by hematoxylin-eosin staining; plasma corticosterone levels, colon ODC expression, and urinary polyamines were determined by competitive ELISA, RT-qPCR, Western Blot, and HPLC, respectively. The short-term exposure to DMH triggered colon inflammation, initiated colon carcinogenesis and increased ODC expression; meanwhile, the exposure to chronic stress activated the hypothalamic-pituitary-adrenal (HPA) axis, elicited the production of plasmatic corticosterone, and decreased ODC expression. The exposure of DMH-treated mice to chronic stress counteracted the inflammatory effect of DMH and maintained ODC homeostasis. In early phase of carcinogenesis, the exposure of DMH-treated mice to chronic stress had a positive effect against colon inflammation and maintained ODC homeostasis. The cross-talk between corticosterone, ODC expression, and inflammation in a tumor environment is discussed.

JAK/STAT pathway inhibition sensitizes CD8 T cells to dexamethasone-induced apoptosis in hyperinflammation

Cytokine storm syndromes (CSS) are severe hyperinflammatory conditions characterized by excessive immune system activation leading to organ damage and death. Hemophagocytic lymphohistiocytosis (HLH), a disease often associated with inherited defects in cell-mediated cytotoxicity, serves as a prototypical CSS for which the 5-year survival is only 60%. Frontline therapy for HLH consists of the glucocorticoid dexamethasone (DEX) and the chemotherapeutic agent etoposide. Many patients, however, are refractory to this treatment or relapse after an initial response. Notably, many cytokines that are elevated in HLH activate the JAK/STAT pathway, and the JAK1/2 inhibitor ruxolitinib (RUX) has shown efficacy in murine HLH models and humans with refractory disease. We recently reported that cytokine-induced JAK/STAT signaling mediates DEX resistance in T cell acute lymphoblastic leukemia (T-ALL) cells, and that this could be effectively reversed by RUX. On the basis of these findings, we hypothesized that cytokine-mediated JAK/STAT signaling might similarly contribute to DEX resistance in HLH, and that RUX treatment would overcome this phenomenon. Using ex vivo assays, a murine model of HLH, and primary patient samples, we demonstrate that the hypercytokinemia of HLH reduces the apoptotic potential of CD8 T cells leading to relative DEX resistance. Upon exposure to RUX, this apoptotic potential is restored, thereby sensitizing CD8 T cells to DEX-induced apoptosis in vitro and significantly reducing tissue immunopathology and HLH disease manifestations in vivo. Our findings provide rationale for combining DEX and RUX to enhance the lymphotoxic effects of DEX and thus improve the outcomes for patients with HLH and related CSS.

Teriflunomide inhibits activation-induced CD25 expression on T cells and may affect Foxp3-expressing regulatory T cells

Teriflunomide (TER) is an immunomodulatory agent. Although the first reports on the use of TER in dogs have already appeared, immune mechanisms underlying the immunomodulatory effect of TER do not seem to have been fully elucidated yet. There were two aspects of this study. First, further insight into the mode of action of TER was gained by investigating its effect on the expression of IL-2 receptor α-chain (CD25) and Forkhead box P3 (Foxp3) by CD4⁺ and CD8⁺ T cells and apoptosis of these cells. Second, in view in the earlier lack of data on the effect of TER on T cells in dogs, the results of this study filled in this gap. TER at a concentration which can be achieved in vivo prevented or reduced the activation-induced CD25 expression on CD4⁺ and CD8⁺ T cells, respectively. Taking into consideration the role of CD25 in T cell proliferation, this effect may constitute an additional mechanism responsible for the antiproliferative effect of the drug. Under stimulation conditions, TER induced Foxp3 expression in Foxp3-negative CD4⁺ and CD8⁺ T cells, while down-regulating it under unstimulated conditions. These results suggest that TER may generate iTreg cells, but this process requires cell activation. TER was not found to affect on the absolute count and apoptosis of CD4⁺ and CD8⁺ T cells. The results suggest that the impairment of CD25 expression during T cell activation and generation of iTreg cells may constitute additional mechanisms, besides the principal one, underlying the immunomodulatory effect of TER.

Immunopathologic Effects of Prednisolone and Cyclosporine A on Feline Immunodeficiency Virus Replication and Persistence

Feline immunodeficiency virus (FIV) induces opportunistic disease in chronically infected cats, and both prednisolone and cyclosporine A (CsA) are clinically used to treat complications such as lymphoma and stomatitis. However, the impact of these compounds on FIV infection are still unknown and understanding immunomodulatory effects on FIV replication and persistence is critical to guide safe and effective therapies. To determine the immunologic and virologic effects of prednisolone and CsA during FIV infection, FIV-positive cats were administered immunosuppressive doses of prednisolone (2 mg/kg) or CsA (5 mg/kg). Both prednisolone and CsA induced acute and transient increases in FIV DNA and RNA loads as detected by quantitative PCR. Changes in the proportion of lymphocyte immunophenotypes were also observed between FIV-infected and naïve cats treated with CsA and prednisolone, and both treatments caused acute increases in CD4+ lymphocytes that correlated with increased FIV RNA. CsA and prednisolone also produced alterations in cytokine expression that favored a shift toward a Th2 response. Pre-treatment with CsA slightly enhanced the efficacy of antiretroviral therapy but did not enhance clearance of FIV. Results highlight the potential for drug-induced perturbation of FIV infection and underscore the need for more information regarding immunopathologic consequences of therapeutic agents on concurrent viral infections.

IL-2 modulates Th2 cell responses to glucocorticosteroid: A cause of persistent type 2 inflammation?

Background

Glucocorticosteroids (GCs) are the main treatment for asthma as they reduce type 2 cytokine expression and induce apoptosis. Asthma severity is associated with type 2 inflammation, circulating Th2 cells and higher GC requirements.

Objective

The aim of this study was to assess whether ex vivo production of interleukin 2 (IL‐2), a T‐cell survival factor, associated with clinical features of asthma severity, the proportion of blood Th2 cells and Th2 cell responses to GC.

Methods

Peripheral blood from asthma patients (n = 18) was obtained and the proportion of Th2 cells determined by flow cytometry. Peripheral blood cells were activated with mitogen (24 hours) and supernatant levels of IL‐2 and IL‐13 measured by enzyme‐linked immunosorbent assay. In vitro differentiated Th2 cells were treated with dexamethasone (DEX) and IL‐2 and assessed for apoptosis by flow cytometry (annexin V). Level of messenger RNA (mRNA) for antiapoptotic (BCL‐2) and proapoptotic (BIM) genes, IL‐13, GC receptor (GR) and FKBP5 were determined by quantitative real‐time polymerase chain reaction. GR binding was assessed by chromatin immunoprecipitation.

Results

IL‐2 produced by activated peripheral blood cells correlated negatively with lung function and positively with a daily dose of inhaled GC. When patients were stratified based on IL‐2 level, high IL‐2 producers made more IL‐13 and had a higher proportion of circulating Th2 cells. In vitro, increasing the level of IL‐2 in the culture media was associated with resistance to DEX‐induced apoptosis, with more BCL‐2/less BIM mRNA. Th2 cells cultured in high IL‐2 had more IL‐13, less GR mRNA, showed reduced binding of the GR to FKBP5, a known GC‐induced gene, and required higher concentrations of DEX for cytokine suppression.

Conclusions and Clinical Relevance

IL‐2 downregulates Th2 cell responses to GC, supporting both their survival and pro‐inflammatory capacity. These results suggest that a patient's potential to produce IL‐2 may be a determinant in asthma severity.

Osteonecrosis in pediatric cancer survivors: Epidemiology, risk factors, and treatment

Several treatment regimens for childhood malignancies have been associated with the development of osteonecrosis, including radiation therapy, glucocorticoid medications, immunotherapy (including anti-angiogenic agents), and several chemotherapeutic agents. Adolescents older than 10 years are at greatest risk of developing osteonecrosis within 1 year of initiating therapy. Screening with magnetic resonance imaging in this high-risk population may be a useful method for detecting osteonecrosis. Surgery may be required for lesions that have progressed substantially despite nonoperative interventions.

Antiemetic doses of dexamethasone and their effects on immune cell populations and plasma mediators of inflammation resolution in healthy volunteers

INTRODUCTION

The synthetic glucocorticoid dexamethasone is a commonly administered antiemetic. It has immunosuppressive effects and may alter postoperative blood glucose concentrations. Dexamethasone can effect key enzymes involved in inflammation resolution that is an active process driven by specialised lipid mediators of inflammation resolution (SPM). The purpose of this study in healthy volunteers was to examine whether dexamethasone effects cell populations and synthesis of SPM that are critical for the resolution of inflammation.

METHODS

Thirty-two healthy volunteers were randomly allocated to receive saline (Control) or dexamethasone 2 mg, 4 mg or 8 mg intravenously. Venous blood samples were collected at baseline before administration of treatment, and at 4 h, 24 h and one-week post-treatment. At each time point, measurements included blood glucose and macrophage migration inhibition factor (MMIF), full blood count including lymphocyte subsets, monocytes, neutrophils, eosinophils and basophils by flow cytometry, and plasma SPM using liquid chromatography tandem mass spectrometry. The effect of dexamethasone dose and time on all measures was analysed using linear mixed models.

RESULTS

There was a dose-dependent increase in neutrophil count after dexamethasone that persisted for 24 h. In contrast, there was a dose-dependent reduction in counts of monocytes, lymphocytes, basophils and eosinophils 4 h after dexamethasone, followed by a rebound increase in cell counts at 24 h. Seven days after administration of dexamethasone, all cell counts were similar to baseline levels. MMIF concentration, glucose and natural killer cell counts were not significantly affected by dexamethasone. There was a significant gender effect on plasma SPM such that levels of 17-HDHA, RvD1, 17R-RvD1 and RvE2 in females were on average 14%-50% lower than males. In a linear mixed model that adjusted for neutrophil count, there was a significant interaction between the dose of dexamethasone and time, on plasma 17R-RvD1 such that plasma 17R-RvD1 fell in a dose-dependent manner until 4 h after administration of dexamethasone. There were no significant effects of dexamethasone on the other plasma SPM (18-HEPE, RvE2, 17-HDHA, RvD1, RvD2 and 14-HDHA) measured.

DISCUSSION

This is the first study in healthy volunteers to demonstrate that commonly employed antiemetic doses of dexamethasone affect immune cell populations and plasma levels of 17R-RvD1 an SPM with anti-nociceptive properties. If similar changes occur in surgical patients, then this may have implications for acute infection risk in the post-operative period.

Excess Hydrocortisone Hampers Placental Nutrient Uptake Disrupting Cellular Metabolism

Low birth weight increases neonatal morbidity and mortality, and surviving infants have increased risk of metabolic and cardiovascular disturbances later in life, as well as other neurological, psychiatric, and immune complications. A gestational excess of glucocorticoids (GCs) is a well-known cause for fetal growth retardation, but the biological basis for this association remains elusive. Placental growth is closely related to fetal growth. The placenta is the main regulator of nutrient transport to the fetus, resulting from the difference between placental nutrient uptake and the placenta's own metabolism. The aim of this study was to analyze how excess hydrocortisone affects placental glucose and lipid metabolism. Human placenta explants from term physiological pregnancies were cultured for 18 hours under different hydrocortisone concentrations (2.75, 5.5, and 55 mM; 1, 2, and 20 mg/ml). Placental glucose and lipid uptake and the metabolic partitioning of fatty acids were quantified by isotopic techniques, and expression of specific glucose transporter GLUT1 was quantified by western blot. Cell viability was assessed by MTT, immunohistochemistry and caspase activity. We found that excess hydrocortisone impairs glucose uptake and lipoprotein lipase (LPL) activity, coincident with a GC-dose dependent inhibition of fatty acid oxidation and esterification. None of the experimental conditions showed an increased cell death. In conclusion, our results show that GC overexposure exerts a dysfunctional effect on lipid transport and metabolism and glucose uptake in human placental explants. These findings could well be directly related to a reduced placental growth and possibly to a reduced supply of nutrients to the fetus and the consequent fetal growth retardation and metabolic programming.

Metabolic reprogramming of acute lymphoblastic leukemia cells in response to glucocorticoid treatment

Glucocorticoids (GCs) are metabolic hormones with immunosuppressive effects that have proven effective drugs against childhood acute lymphoblastic leukemia (ALL). Yet, the role of metabolic reprogramming in GC-induced ALL cell death is poorly understood. GCs efficiently block glucose uptake and metabolism in ALL cells, but this does not fully explain the observed induction of autophagy and cell death. Here, we have performed parallel time-course proteomics, metabolomics, and isotope-tracing studies to examine in detail the metabolic effects of GCs on ALL cells. We observed metabolic events associated with growth arrest, autophagy, and catabolism prior to onset of apoptosis: nucleotide de novo synthesis was reduced, while certain nucleobases accumulated; polyamine synthesis was inhibited; and phosphatidylcholine synthesis was induced. GCs suppressed not only glycolysis but also entry of both glucose and glutamine into the TCA cycle. In contrast, expression of glutamine-ammonia ligase (GLUL) and cellular glutamine content was robustly increased by GC treatment, suggesting induction of glutamine synthesis, similar to nutrient-starved muscle. Modulating medium glutamine and dimethyl-α-ketoglutarate (dm-αkg) to favor glutamine synthesis reduced autophagosome content of ALL cells, and dm-αkg also rescued cell viability. These data suggest that glutamine synthesis affects autophagy and possibly onset of cell death in response to GCs, which should be further explored to understand mechanism of action and possible sources of resistance.

Sequential gene regulatory events leading to glucocorticoid-evoked apoptosis of CEM human leukemic cells:interactions of MAPK, MYC and glucocorticoid pathways

Gene expression responses to glucocorticoid (GC) in the hours preceding onset of apoptosis were compared in three clones of human acute lymphoblastic leukemia CEM cells. Between 2 and 20h, all three clones showed increasing numbers of responding genes. Each clone had many unique responses, but the two responsive clones showed a group of responding genes in common, different from the resistant clone. MYC levels and the balance of activities between the three major groups of MAPKs are known important regulators of glucocorticoid-driven apoptosis in several lymphoid cell systems. Common to the two sensitive clones were changed transcript levels from genes that decrease amounts or activity of anti-apoptotic ERK/MAPK1 and JNK2/MAPK9, or of genes that increase activity of pro-apoptotic p38/MAPK14. Down-regulation of MYC and several MYC-regulated genes relevant to MAPKs also occurred in both sensitive clones. Transcriptomine comparisons revealed probable NOTCH-GC crosstalk in these cells.

C‑Myc inhibitor 10058‑F4 increases the efficacy of dexamethasone on acute lymphoblastic leukaemia cells

The long‑term survival rate in paediatric acute lymphoblastic leukaemia (ALL) exceeds 80%; however, the outcome of adult ALL remains to be poor. Glucocorticoids (GCs) are the preferred drugs in the traditional treatment of ALL patients. In the anti‑leukaemia molecular mechanisms of GCs, c‑Myc inhibition serves a critical role. In the present study, a c‑Myc inhibitor that increased the sensitivity to GCs in NALM6 cells of the B‑cell‑ALL cell line and CEM cells of the T‑cell‑ALL cell line was investigated. The data demonstrated that 10058‑F4, a c‑Myc inhibitor, increased the growth inhibition, G0/G1 phase arrest and apoptosis of the NALM6 and CEM cells as induced by dexamethasone (DXM), a type of GC. Additionally, 10058‑F4 reinforced the decreased expressions of c‑Myc, cyclin‑dependent kinase (CDK)‑4 and CDK6 in the NALM6 and CEM cells treated with DXM. These findings indicated that DXM in combination with the c‑Myc inhibitor 10058‑F4 may be a novel, potent therapeutic strategy for the treatment of ALL.

T-cell acute lymphoblastic leukemia from miRNA perspective: Basic concepts, experimental approaches, and potential biomarkers

T-cell acute lymphoblastic leukemia (T-ALL) is a rare, aggressive and heterogeneous malignancy originating from T-cell precursors. The mechanisms of T-ALL pathogenesis related to non-protein coding part of the genome are currently intensively studied. miRNAs are short, non-coding molecules acting as negative regulators of gene expression which shape phenotype of cells in a complex and context-specific manner. miRNAs may act as oncogenes or tumor suppressors; several miRNAs have been related to drug resistance and treatment response in various malignancies. Here we present the review of the state-of-the-art knowledge on the role of miRNAs in T-ALL pathogenesis, with detailed overview of the studies reporting on miRNAs with oncogenic and tumor suppressor potential. We discuss whether miRNAs might be considered candidate biomarkers of prognosis in T-ALL and leukemia subtype-specific markers. We also describe experimental approaches and a typical workflow applied in research on the involvement of miRNAs in oncogenesis.

Glucocorticoid receptor activation is associated with increased resistance to heat-induced hyperthermia and injury

AIM

Anti-inflammatory mediators likely play a key role in maintaining thermal homeostasis and providing protection against heat stress. The aim of this study was to investigate the association between activation of the glucocorticoid receptor (GR) and resistance to heat-induced hyperthermia and injury.

METHODS

Effects of heat exposure on core body temperature, muscle GR phosphorylation status and subcellular expression were examined in control mice and thermal acclimation (TA)-exposed mice. In addition, effects of TA and corticosterone on C2C12 mouse myoblast viability and subcellular GR were assessed during heat exposure.

RESULTS

Phosphorylated, nuclear and mitochondrial GR levels were significantly higher in the gastrocnemius muscles of mice with mild hyperthermia (tolerant), compared to mice with severe hyperthermia (intolerant) during a heat exposure test. Similar changes were found in mice after TA, compared to non-TA-exposed controls. Additional groups of TA and non-TA-exposed mice underwent a heat exposure test. TA mice presented a significantly lower hyperthermic response during heat exposure than non-TA-exposed control. C2C12 cells exposed to TA incubation had higher viability against heat shock and showed higher GR levels in their mitochondria and nuclei detected by Western blot analysis and fluorescence microscopy, compared to cells exposed to normal incubation. Furthermore, pre-incubation with 0.1 μM corticosterone increased C2C12 cell viability during heat exposure and mitochondrial and nuclear GR expression.

CONCLUSION

The results of these in vivo and in vitro studies suggest that GR activation is associated with increased resistance against heat-induced hyperthermia and injury.

Mechanism of inhibition of Shiga-toxigenic Escherichia coli SubAB cytotoxicity by steroids and diacylglycerol analogues

Shiga toxigenic Escherichia coli (STEC) are responsible for a worldwide foodborne disease, which is characterized by severe bloody diarrhea and hemolytic uremic syndrome (HUS). Subtilase cytotoxin (SubAB) is a novel AB₅ toxin, which is produced by Locus for Enterocyte Effacement (LEE)-negative STEC. Cleavage of the BiP protein by SubAB induces endoplasmic reticulum (ER) stress, followed by induction of cytotoxicity in vitro or lethal severe hemorrhagic inflammation in mice. Here we found that steroids and diacylglycerol (DAG) analogues (e.g., bryostatin 1, Ingenol-3-angelate) inhibited SubAB cytotoxicity. In addition, steroid-induced Bcl-xL expression was a key step in the inhibition of SubAB cytotoxicity. Bcl-xL knockdown increased SubAB-induced apoptosis in steroid-treated HeLa cells, whereas SubAB-induced cytotoxicity was suppressed in Bcl-xL overexpressing cells. In contrast, DAG analogues suppressed SubAB activity independent of Bcl-xL expression at early time points. Addition of Shiga toxin 2 (Stx2) with SubAB to cells enhanced cytotoxicity even in the presence of steroids. In contrast, DAG analogues suppressed cytotoxicity seen in the presence of both toxins. Here, we show the mechanism by which steroids and DAG analogues protect cells against SubAB toxin produced by LEE-negative STEC.

Immune Suppressive and Bone Inhibitory Effects of Prednisolone in Growing and Regenerating Zebrafish Tissues

Glucocorticoids are widely used as therapeutic agents to treat immune-mediated diseases in humans because of their anti-inflammatory and immunosuppressive effects. However, glucocorticoids have various adverse effects, in particular rapid and pronounced bone loss associated with fractures in glucocorticoid-induced osteoporosis, a common form of secondary osteoporosis. In zebrafish, which are increasingly used to study processes of bone regeneration and disease, glucocorticoids show detrimental effects on bone tissue; however, the underlying cellular mechanisms are incompletely understood. Here, we show that treatment with the glucocorticoid prednisolone impacts on the number, activity and differentiation of osteoblasts, osteoclasts, and immune cells during ontogenetic growth, homeostasis, and regeneration of zebrafish bone. Macrophage numbers are reduced in both larval and adult tissues, correlating with decreased generation of myelomonocytes and enhanced apoptosis of these cells. In contrast, osteoblasts fail to proliferate, show decreased activity, and undergo incomplete differentiation. In addition, prednisolone treatment mitigates the number and recruitment of osteoclasts to sites of bone regeneration in adult fish. In combination, these effects delay bone growth and impair bone regeneration. Our study demonstrates the many-faceted effects of glucocorticoids in non-mammalian vertebrates and helps to further establish the zebrafish as a model to study glucocorticoid-induced osteoporosis. © 2017 American Society for Bone and Mineral Research.

Acute mental stress induces mitochondrial bioenergetic crisis and hyper-fission along with aberrant mitophagy in the gut mucosa in rodent model of stress-related mucosal disease

Psychological stress, depression and anxiety lead to multiple organ dysfunctions wherein stress-related mucosal disease (SRMD) is common to people experiencing stress and also occur as a side effect in patients admitted to intensive care units; however the underlying molecular aetiology is still obscure. We report that in rat-SRMD model, cold restraint-stress severely damaged gut mitochondrial functions to generate superoxide anion (O₂^•-), depleted ATP and shifted mitochondrial fission-fusion dynamics towards enhanced fission to induce mucosal injury. Activation of mitophagy to clear damaged and fragmented mitochondria was evident from mitochondrial translocation of Parkin and PINK1 along with enhanced mitochondrial proteome ubiquitination, depletion of mitochondrial DNA copy number and TOM 20. However, excess and sustained accumulation of O₂^•--generating defective mitochondria overpowered the mitophagic machinery, ultimately triggering Bax-dependent apoptosis and NF-κB-intervened pro-inflammatory mucosal injury. We further observed that stress-induced enhanced serum corticosterone stimulated mitochondrial recruitment of glucocorticoid receptor (GR), which contributed to gut mitochondrial dysfunctions as documented from reduced ETC complex 1 activity, mitochondrial O₂^•- accumulation, depolarization and hyper-fission. GR-antagonism by RU486 or specific scavenging of mitochondrial O₂^•- by a mitochondrially targeted antioxidant mitoTEMPO ameliorated stress-induced mucosal damage. Gut mitopathology and mucosal injury were also averted when the perception of mental stress was blocked by pre-treatment with a sedative or antipsychotic. Altogether, we suggest the role of mitochondrial GR-O₂^•--fission cohort in brain-mitochondria cross-talk during acute mental stress and advocate the utilization of this pathway as a potential target to prevent mitochondrial unrest and gastropathy bypassing central nervous system.

Corticosterone influences gerbil (Meriones unguiculatus) prostatic morphophysiology and alters its proliferation and apoptosis rates

Glucocorticoids (GCs) are hormones that are widely used in medicine; but although side effects are generally recognised, little is known about the precise mechanisms that is implicated in many of these side effects. Furthermore, GCs are highly correlated with stress and behaviour disorders. This study evaluated the effects of the glucocorticoid corticosterone on the ventral prostate of the Mongolian gerbil. Male gerbils (Meriones unguiculatus) (n = 5) received intraperitoneal injections of saline or corticosterone in doses of 0.5 mg/kg/day and 1.5 mg/kg/day for 5 days; while some of the animals were killed immediately after the treatment, the others were killed 5 days after the treatment period. The data show that corticosterone influences the structure and functionality of this organ. This hormone has anti-proliferative and anti-apoptotic properties in the prostate. In addition, the frequencies of the androgen (AR), oestrogen (ERα, ERβ) and glucocorticoid (GR) receptors changed. The frequencies of AR, GR and ERβ decreased in the Ct1/5 group; in the groups with rest period, the frequencies of GR increased and ERβ decreased in the epithelium. Changes in the proliferative index, apoptotic index and receptor activity may have contributed to the emergence of prostatic morphological alterations, such as the presence of cellular debris and inflammatory cells. Different doses of corticosterone had variable effects on the prostate, with a higher dose showing subtler effects and a lower dose showing more striking effects. The corticosterone effects on nuclear receptors were reverted or attenuated after a rest period, which was not observed for proliferation and apoptosis. In summary, we have demonstrated that corticosterone might influence the prostatic morphophysiology and that these changes may be linked in some way to the altered receptor distribution.

Melatonin modulates glucocorticoid receptor mediated inhibition of antioxidant response and apoptosis in peripheral blood mononuclear cells

Pineal melatonin is known for its immunomodulatory and anti-stress properties. It modulates stress condition by regulating antioxidant responses and apoptosis in the immune cells. Stress causes increased glucocorticoid level that acts through glucocorticoid receptor (GR) and is translocated into nucleus under regulation of HSP90 based chaperone machinery. Melatonin influences glucocorticoid and GR mediated stress condition in rodents, but till date there are no reports which could suggest the effect of melatonin treatment on GR mediated apoptosis and inhibition of Nrf-2/hemeoxygenase-1 (HO-1) induced antioxidant status in immunocompetent cells (peripheral blood mononuclear cells; PBMCs). Therefore, in the present study, we considered GR mediated inhibition of Nrf2 and HO-1 along with anti-apoptotic Bcl-2 expression in PBMCs. The PBMCs were treated with synthetic glucocorticoid; dexamethasone (Dex) and melatonin (Mel), to explore the effect of melatonin treatment in regulation of GR mediated apoptosis and inhibition of antioxidant status in immune cells. It was noted that melatonin treatment retained GR into cytoplasm by inhibiting the dissociation of HSP90 from GR-HSP90 complex and enhanced expression of Nrf2/HO-1 and Bcl-2 expression. This led to increased HO-1 expression and elevated Bcl-2 led to increased Bcl-2/Bax ratio that might ultimately enhanced the cellular antioxidant response and survival under glucocorticoid mediated stress condition. Our observations suggest that the declined GR nuclear translocation upon melatonin treatment might be responsible for the up-regulation of Nrf2 mediated HO-1 activity and increased Bcl-2/Bax ratio in PBMCs to maintain the immune homeostasis under stress condition.

Aluminum chloride induced splenic lymphocytes apoptosis through NF-κB inhibition

This research investigated the relationship between lymphocytes apoptosis, hypothalamic-pituitary-adrenal (HPA) axis and NF-κB in AlCl3-treated rats. Eighty Wistar rats were orally exposed to 0 (control group, CG), 0.4 mg/mL (low-dose group, LG), 0.8 mg/mL (mid-dose group, MG) and 1.6 mg/mL (high-dose group, HG) AlCl3 for 90 days, respectively. A variety of measurements were taken including lymphocyte apoptosis index, serum corticotropin-releasing hormone (CRH), adrenocorticotrophic hormone (ACTH) and glucocorticoids (GCs) contents, GC receptors (GCR) and NF-κB mRNA and nuclear protein expressions, caspase 3 and 9 mRNA expressions and activities. The results showed that in the AlCl3-treated rats serum CRH, ACTH and GCs contents, lymphocyte GC receptors (GCR) mRNA and nuclear protein expressions, caspase 3 and 9 mRNA expressions and activities increased, while Bcl-2/Bax ratio and NF-κB mRNA and nuclear protein expressions decreased compared with the CG. Furthermore GCR and NF-κB nuclear protein expressions were negatively correlated. And NF-κB mRNA expression was positively correlated with that of Bcl-2, but negatively correlated with that of Bax in AlCl3-treated rats. These findings indicated that AlCl3 activated HPA axis, then induced splenic lymphocytes apoptosis through NF-κB inhibition.

Dexamethasone-induced cell death is restricted to specific molecular subgroups of multiple myeloma

Due to its cytotoxic effect in lymphoid cells, dexamethasone is widely used in the treatment of multiple myeloma (MM). However, only a subset of myeloma patients responds to high-dose dexamethasone. Despite the undeniable anti-myeloma benefits of dexamethasone, significant adverse effects have been reported. We re-evaluate the anti-tumor effect of dexamethasone according to the molecular heterogeneity of MM. We demonstrated that the pro-death effect of dexamethasone is related to the genetic heterogeneity of MM because sensitive cell lines were restricted to MAF and MMSET signature subgroups, whereas all CCND1 cell lines (n = 10) were resistant to dexamethasone. We demonstrated that the glucocorticoid receptor expression was an important limiting factor for dexamethasone-induced cell death and we found a correlation between glucocorticoid receptor levels and the induction of glucocorticoid-induced leucine zipper (GILZ) under dexamethasone treatment. By silencing GILZ, we next demonstrated that GILZ is necessary for Dex induced apoptosis while triggering an imbalance between anti- and pro-apoptotic Bcl-2 proteins. Finally, the heterogeneity of the dexamethasone response was further confirmed in vivo using myeloma xenograft models. Our findings suggested that the effect of dexamethasone should be re-evaluated within molecular subgroups of myeloma patients to improve its efficacy and reduce its adverse effects.

Influence of commonly used pharmaceutical agents on equine bone marrow-derived mesenchymal stem cell viability

REASON FOR PERFORMING STUDY

To provide evidence to support recommendations regarding the co-administration of drugs with mesenchymal stem cell (MSC) therapy.

OBJECTIVES

To determine the influence of sedatives, local anaesthetic and corticosteroids on MSC viability and proliferation, in comparison to somatic cells derived from tendon (TDCs).

STUDY DESIGN

In vitro cell culture.

MATERIALS AND METHODS

MSCs (n = 3) and TDCs (n = 2) were cultured in media containing a clinically relevant dose range of xylazine, romifidine, detomidine and butorphanol, mepivacaine, methylprednisolone, or triamcinolone acetonide. Cell viability in suspension culture was assessed at intervals up to 4 h using the trypan blue dye assay. MSCs in monolayer culture were exposed to the highest concentrations of drug and proliferation was measured using the alamarBlue fluorescence assay.

RESULTS

Exposure to romifidine or mepivacaine did not significantly affect viability or proliferation rate of MSCs or TDCs at any of the dosages tested. At the highest concentration of detomidine and butorphanol, MSC viability was significantly reduced compared to controls. Although xylazine exposure caused a significant (P < 0.001), dose-dependent reduction in MSC viability compared to controls, overall population viability remained good. Conversely, both methylprednisolone and triamcinolone resulted in the rapid death of significant numbers of MSCs (P < 0.001).

CONCLUSIONS

Clinicians can sedate horses and administer nerve blocks to assist in intratendinous or intrathecal injection of MSCs with confidence that these drugs will not impact the viability of implanted cells. However, the concomitant use of corticosteroids is likely to have a severely detrimental effect on cell viability and should not be performed. Similarly, steroid administration into the sheath of a damaged tendon is not recommended.

MEK Inhibition Sensitizes Precursor B-Cell Acute Lymphoblastic Leukemia (B-ALL) Cells to Dexamethasone through Modulation of mTOR Activity and Stimulation of Autophagy

Resistance to glucocorticosteroids (GCs) is a major adverse prognostic factor in B-ALL, but the molecular mechanisms leading to GC resistance are not completely understood. Herein, we sought to elucidate the molecular background of GC resistance in B-ALL and characterize the therapeutic potential of targeted intervention in these mechanisms. Using exploratory bioinformatic approaches, we found that resistant cells exhibited significantly higher expression of MEK/ERK (MAPK) pathway components. We found that GC-resistant ALL cell lines had markedly higher baseline activity of MEK and small-molecule MEK1/2 inhibitor selumetinib increased GCs-induced cell death. MEK inhibitor similarly increased in vitro dexamethasone activity in primary ALL blasts from 19 of 22 tested patients. To further confirm these observations, we overexpressed a constitutively active MEK mutant in GC-sensitive cells and found that forced MEK activity induced resistance to dexamethasone. Since recent studies highlight the role GC-induced autophagy upstream of apoptotic cell death, we assessed LC3 processing, MDC staining and GFP-LC3 relocalization in cells incubated with either DEX, SEL or combination of drugs. Unlike either drug alone, only their combination markedly increased these markers of autophagy. These changes were associated with decreased mTOR activity and blocked 4E-BP1 phosphorylation. In cells with silenced beclin-1 (BCN1), required for autophagosome formation, the synergy of DEX and SEL was markedly reduced. Taken together, we show that MEK inhibitor selumetinib enhances dexamethasone toxicity in GC-resistant B-ALL cells. The underlying mechanism of this interaction involves inhibition of mTOR signaling pathway and modulation of autophagy markers, likely reflecting induction of this process and required for cell death. Thus, our data demonstrate that modulation of MEK/ERK pathway is an attractive therapeutic strategy overcoming GC resistance in B-ALL patients.

Chronic stress increases experimental pancreatic cancer growth, reduces survival and can be antagonised by beta-adrenergic receptor blockade

BACKGROUND/OBJECTIVES

Chronic stress could promote tumour growth and reduce survival of pancreatic cancer patients via beta-adrenergic receptors of tumour cells. We have tested the impact of chronic acoustic and restraint stress on tumour development in an orthotopic syngeneic murine model of pancreatic cancer.

METHODS AND RESULTS

Tumour-bearing C57BL/6 mice exposed to chronic stress had 45% (p = 0.0138) higher circulating steroid and 111% (p = 0.0052) higher adrenal tyrosine hydroxylase levels. Their immune response was significantly suppressed: The in vitro LPS response of splenocytes was significantly reduced regarding Th1- and Th2-cytokines including IFN-gamma, IL-6, IL-10 and MCP-1 (0.0011 < p < 0.043). Also, tumours of stressed mice showed a tendency towards fewer total CD4 cells, more regulatory T cells (Treg), less T cell/tumour cell contacts and a reduction of CTLA-4 in CD4 cells (p > 0.05). TGF-beta in vitro was increased by 23.4% using catecholamines (p < 0.012) and in vivo employing chronic stress (p < 0.001). After 5 weeks tumour volumes were 130% (p = 0.0061) larger and median survival reduced by 13.5% (p = 0.0058). Tumours expressed more VEGF (p = 0.0334), had greater microvessel densities (p = 0.047), and an increased MMP-9 expression (p = 0.0456). Beta-catecholamines increased proliferation in tumour cells by 18% (p < 0.0001) and migration by 78% (p = 0.0348) whereas the beta-blocker propranolol reduced these effects by 25% (p < 0.0001) and 53% (p = 0.045), respectively. When stressed tumour-bearing animals were treated with propranolol tumour volumes were reduced by 69% (p = 0.0088) and survival improved by 14% (p < 0.0058).

CONCLUSIONS

The potential treatment with beta-blockers of patients with pancreatic cancer or other malignancies should be further evaluated as an adjuvant anti-neoplastic agent in clinical trials.

PRIMA-1Met induces apoptosis in Waldenström's Macroglobulinemia cells independent of p53

PRIMA-1Met has shown promising preclinical activity in various cancer types. However, its effect on Waldenström's Macroglobulinemia (WM) cells as well as its exact mechanism of action is still elusive. In this study, we evaluated the anti- tumor activity of PRIMA-1Met alone and in combination with dexamethasone or bortezomib in WM cell lines and primary samples. Treatment of WM cells with PRIMA-1Met resulted in induction of apoptosis, inhibition of migration and suppression of colony formation. Upon PRIMA-1Met treatment, p73 was upregulated and Bcl-xL was down-regulated while no significant change in expression of p53 was observed. Furthermore, siRNA knockdown of p53 in WM cell line did not influence the PRIMA-1Met-induced apoptotic response whereas silencing of p73 inhibited latter response in WM cells. Importantly, combined treatment of BCWM-1 cells with PRIMA-1Met and dexamethasone or bortezomib induced synergistic reduction in cell survival. Our study provides insights into the mechanisms of anti-WM activity of PRIMA-1Met and supports further clinical evaluation of PRIMA-1Met as a potential novel therapeutic intervention in WM.

Folylpolyglutamate synthetase splicing alterations in acute lymphoblastic leukemia are provoked by methotrexate and other chemotherapeutics and mediate chemoresistance

Methotrexate (MTX), a folate antagonist which blocks de novo nucleotide biosynthesis and DNA replication, is an anchor drug in acute lymphoblastic leukemia (ALL) treatment. However, drug resistance is a primary hindrance to curative chemotherapy in leukemia and its molecular mechanisms remain poorly understood. We have recently shown that impaired folylpolyglutamate synthetase (FPGS) splicing possibly contributes to the loss of FPGS activity in MTX-resistant leukemia cell line models and adult leukemia patients. However, no information is available on the possible splicing alterations in FPGS in pediatric ALL. Here, using a comprehensive PCR-based screen we discovered and characterized a spectrum of FPGS splicing alterations including exon skipping and intron retention, all of which proved to frequently emerge in both pediatric and adult leukemia patient specimens. Furthermore, an FPGS activity assay revealed that these splicing alterations resulted in loss of FPGS function. Strikingly, pulse-exposure of leukemia cells to antifolates and other chemotherapeutics markedly enhanced the prevalence of several FPGS splicing alterations in antifolate-resistant cells, but not in their parental antifolate-sensitive counterparts. These novel findings suggest that an assortment of deleterious FPGS splicing alterations may constitute a mechanism of antifolate resistance in childhood ALL. Our findings have important implications for the rational overcoming of drug resistance in individual leukemia patients.

To have and have not: dissecting protective and pathologic immune recovery in TB-IRIS

Paradoxical tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a growing concern for advanced HIV/TB coinfected patients in an era where antiretroviral therapy (ART) is started shortly after TB treatment initiation. This perspective discusses potential mechanisms underlying TB-IRIS, focusing on recent studies that implicate coordinated recovery in adaptive and innate immune responses following ART initiation in TB-IRIS. More broadly, HIV/TB patients are probably a heterogeneous group whose outcomes are determined by the direction in which these immune responses change following ART initiation. Finally, in addition to treatment interventions that are in the pipeline for TB-IRIS, we highlight the need for holistic management of HIV/TB coinfected patients, which go beyond the current definition of TB-IRIS and take into consideration long-term consequences of robust immune recovery on ART.

Paclitaxel-induced transcriptional regulation of Fas signaling pathway is antagonized by dexamethasone

Chemotherapy agents like paclitaxel are often a first line of therapy for triple-negative breast cancer patients and a last line of therapy for other aggressive breast cancers. While such agents are effective pro-apoptotic treatments for breast cancer cells, they produce many unwanted side effects. Synthetic glucocorticoids like dexamethasone are commonly prescribed during chemotherapy treatment of breast cancer patients for anti-emetic and anti-hypersensitivity purposes. Dexamethasone, however, is known to enhance cell survival in solid tumors. The prevalent use of dexamethasone in conjunction with paclitaxel in the treatment of breast cancer patients merits concern. Previous studies demonstrate dexamethasone-mediated survival in a subset of breast cancer cells in the presence of paclitaxel. This work expanded the types of cell lines studied and explored the molecular mechanism driving this phenotype. Human breast cancer cell lines representative of several subtypes of breast cancer including triple-negative breast cancer, luminal, and HER2 were treated in the presence and absence of paclitaxel, dexamethasone, and under co-treatment conditions. Cell survival was monitored under differing conditions. We then manipulated aspects of the nuclear factor kappa B (NFkappaB) signaling pathway to elucidate the importance of this pathway in overcoming chemotherapy treatment. All cell lines tested were sensitive to paclitaxel and showed dexamethasone-mediated rescue from paclitaxel-induced apoptosis, but the rescue of overall cell numbers was most pronounced in triple-negative breast cancer cell lines. Dexamethasone and paclitaxel inversely regulated the activity of NFkappaB, which is essential to both paclitaxel-mediated apoptosis and dexamethasone-mediated rescue. The transcriptional target of NFkappaB, Fas receptor, is inversely regulated by paclitaxel and dexamethasone and is a downstream target of paclitaxel-activated NFkappaB. Dexamethasone antagonizes paclitaxel-mediated apoptosis through inhibition of NFkappaB transcription of Fas receptor. Pre-treatment of breast cancer patients with dexamethasone may greatly reduce patient response to paclitaxel. Our study elucidates a novel mechanism of paclitaxel-induced apoptosis in breast cancer cell lines and explicates dexamethasone’s antagonism of paclitaxel.

Targeting the miR-221-222/PUMA/BAK/BAX Pathway Abrogates Dexamethasone Resistance in Multiple Myeloma

Despite recent therapeutic advances that have doubled the median survival time of patients with multiple myeloma, intratumor genetic heterogeneity contributes to disease progression and emergence of drug resistance. miRNAs are noncoding small RNAs that play important roles in the regulation of gene expression and have been implicated in cancer progression and drug resistance. We investigated the role of the miR-221-222 family in dexamethasone-induced drug resistance in multiple myeloma using the isogenic cell lines MM1R and MM1S, which represent models of resistance and sensitivity, respectively. Analysis of array comparative genome hybridization data revealed gain of chromosome X regions at band p11.3, wherein the miR-221-222 resides, in resistant MM1R cells but not in sensitive MM1S cells. DNA copy number gains in MM1R cells were associated with increased miR-221-222 expression and downregulation of p53-upregulated modulator of apoptosis (PUMA) as a likely proapoptotic target. We confirmed PUMA mRNA as a direct target of miR-221-222 in MM1S and MM1R cells by both gain-of-function and loss-of-function studies. In addition, miR-221-222 treatment rendered MM1S cells resistant to dexamethasone, whereas anti-miR-221-222 partially restored the dexamethasone sensitivity of MM1R cells. These studies have uncovered a role for miR-221-222 in multiple myeloma drug resistance and suggest a potential therapeutic role for inhibitors of miR-221-222 binding to PUMA mRNA as a means of overcoming dexamethasone resistance in patients. The clinical utility of this approach is predicated on the ability of antisense miR-221-222 to increase survival while reducing tumor burden and is strongly supported by the metastatic propensity of MM1R cells in preclinical mouse xenograft models of multiple myeloma. Moreover, our observation of increased levels of miR-221-222 with decreased PUMA expression in multiple myeloma cells from patients at relapse versus untreated controls suggests an even broader role for miR-221-222 in drug resistance and provides a rationale for the targeting of miR-221-222 as a means of improving patient outcomes.

Subchronic glucocorticoid receptor inhibition rescues early episodic memory and synaptic plasticity deficits in a mouse model of Alzheimer's disease

The early phase of Alzheimer's disease (AD) is characterized by hippocampus-dependent memory deficits and impaired synaptic plasticity. Increasing evidence suggests that stress and dysregulation of the hypothalamo-pituitary-adrenal (HPA) axis, marked by the elevated circulating glucocorticoids, are risk factors for AD onset. How these changes contribute to early hippocampal dysfunction remains unclear. Using an elaborated version of the object recognition task, we carefully monitored alterations in key components of episodic memory, the first type of memory altered in AD patients, in early symptomatic Tg2576 AD mice. We also combined biochemical and ex vivo electrophysiological analyses to reveal novel cellular and molecular dysregulations underpinning the onset of the pathology. We show that HPA axis, circadian rhythm, and feedback mechanisms, as well as episodic memory, are compromised in this early symptomatic phase, reminiscent of human AD pathology. The cognitive decline could be rescued by subchronic in vivo treatment with RU486, a glucocorticoid receptor antagonist. These observed phenotypes were paralleled by a specific enhancement of N-Methyl-D-aspartic acid receptor (NMDAR)-dependent LTD in CA1 pyramidal neurons, whereas LTP and metabotropic glutamate receptor-dependent LTD remain unchanged. NMDAR transmission was also enhanced. Finally, we show that, as for the behavioral deficit, RU486 treatment rescues this abnormal synaptic phenotype. These preclinical results define glucocorticoid signaling as a contributing factor to both episodic memory loss and early synaptic failure in this AD mouse model, and suggest that glucocorticoid receptor targeting strategies could be beneficial to delay AD onset.

Immunological profiling of tuberculosis-associated immune reconstitution inflammatory syndrome and non-immune reconstitution inflammatory syndrome death in HIV-infected adults with pulmonary tuberculosis starting antiretroviral therapy: a prospective observational cohort study

BACKGROUND

Patients co-infected with advanced HIV and tuberculosis are at risk of tuberculosis-associated immune reconstitution inflammatory syndrome (IRIS) and death soon after initiation of antiretroviral therapy (ART). Tuberculosis-associated IRIS has been associated with quicker recovery of cellular immune responses after ART initiation and early mortality with slower recovery of these responses. We aimed to assess whether patients who have these outcomes have distinct immunological profiles before and after ART initiation.

METHODS

We undertook this prospective cohort study at 22 public clinics and the main public hospital in Gaborone, Botswana, in ART-naive adults (aged ≥21 years) with advanced HIV (CD4 cell counts ≤125 cells per μL) and pulmonary tuberculosis. We obtained data for clinical variables and for levels of 29 plasma biomarkers, quantified by Luminex assay. We classified patients as having tuberculosis-associated IRIS, early mortality, or survival without a diagnosis of tuberculosis-associated IRIS (controls), on the basis of outcomes recorded in the 6 months after ART initiation. We used rank-sum or χ(2) tests, and logistic regression with odds ratios (OR) and 95% CIs, to assess the association between variables measured before and 4 weeks after ART initiation with death and tuberculosis-associated IRIS, compared with controls.

FINDINGS

Between Nov 12, 2009, and July 3, 2013, we enrolled 201 participants. 31 (15%) patients left the study before ART initiation, leaving 170 (85%) patients for analysis. Patients with tuberculosis-associated IRIS had reduced pre-ART concentrations of several pro-inflammatory biomarkers, including interleukin (IL)-6 (adjusted OR per 1 log10 increase 0·40 [95% CI 0·18-0·89]). However, patients with early death had increased pre-ART concentrations of inflammatory biomarkers, including monocyte chemoattractant protein-1 (adjusted OR 9·0 [95% CI 1·0-80·0]) and tumour necrosis factor (TNF)α (7·8 [1·1-55·2]). At week 4 after ART initation, tuberculosis-associated IRIS was independently associated with greater increases in several inflammatory biomarkers, including IL-6 (adjusted OR 1·7 [95% CI 1·2-2·5]) and TNFα (1·5 [1·0-2·2]), versus controls. Death was likewise associated with greater increases in systemic inflammatory markers, including granulocyte colony-stimulating factor (adjusted OR 2·8 [95% CI 1·3-6·1]), IL-12p40 (1·8 [1·0-3·4]), and IL-15 (2·0 [1·1-3·7]), versus controls. However, changes in CD4 cell count during ART, which were similar between controls and patients with tuberculosis-associated IRIS (p=0·45), were substantially lower in patients who died (p=0·006).

INTERPRETATION

Distinct immunological profiles before and after ART initiation characterise patients with advanced HIV and tuberculosis who have tuberculosis-associated IRIS and death. Interventions that decrease inflammation while promoting cellular immune recovery during ART should be considered in patients co-infected with HIV and tuberculosis.

FUNDING

National Institutes of Health and the Penn Center for AIDS Research.

Effects of Glucocorticoids in the Immune System

Glucocorticoids (GCs) are steroid hormones with widespread effects. They control intermediate metabolism by stimulating gluconeogenesis in the liver, mobilize amino acids from extra hepatic tissues, inhibit glucose uptake in muscle and adipose tissue, and stimulate fat breakdown in adipose tissue. They also mediate stress response. They exert potent immune-suppressive and anti-inflammatory effects particularly when administered pharmacologically. Understanding these diverse effects of glucocorticoids requires a detailed knowledge of their mode of action. Research over the years has uncovered several details on the molecular action of this hormone, especially in immune cells. In this chapter, we have summarized the latest findings on the action of glucocorticoids in immune cells with a view of identifying important control points that may be relevant in glucocorticoid therapy.

The selective impact of transgenically expressed glucocorticoid receptor on T cells

Glucocorticoids (GCs) strongly impact on different T cell subsets inducing generally immunosuppressive effects, whereas much less is known about the effect of GC on natural killer (NK) cells. The aims of this study were to investigate the effects of GC on T cell functions, including T cell-mediated anti-tumor immune response, and on NK cells. We have used lck-GR mice, which overexpress a transgenic rat GR in both T and NK cells. These mice were found to have decreased both CD4(+) and CD8(+) T cell populations in the periphery. In contrast, both NK and NKT cells were found in normal numbers in lck-GR mice. To identify genes and pathways affected by GR overexpression in our system in T cells, we have compared gene expression profiles in wild-type and lck-GR T cells. Among the genes upregulated in T cells from lck-GR mice, the microarray analysis has identified genes regulating expansion of regulatory T cells. The analysis of genes downregulated in lck-GR mice has identified genes and gene associated with the regulation of immune response. With regard to the effects on T cell functions in lck-GR mice, transgenic expression of GR had a suppressive effect on killer cell activity in vitro. In addition, lck-GR mice showed an increased tumor growth in murine tumor model in vivo, which may be a possible consequence of reduced T cell numbers and activity. We conclude that an increased expression of the GR strongly affects numbers and possibly functions of T cell subsets, but has little effect on NK cells.

Performance-enhanced mesenchymal stem cells via intracellular delivery of steroids

Inadequate immunomodulatory potency of mesenchymal stem cells (MSC) may limit their therapeutic efficacy. We report glucocorticoid steroids augment MSC expression and activity of indoleamine-2,3-dioxygenase (IDO), a primary mediator of MSC immunomodulatory function. This effect depends on signaling through the glucocorticoid receptor and is mediated through up-regulation of FOXO3. Treatment of MSCs with glucocorticoids, budesonide or dexamethasone, enhanced IDO expression following IFN-γ stimulation in multiple donors and was able to restore IDO expression in over-passaged MSCs. As IDO enhancement was most notable when cells were continuously exposed to budesonide, we engineered MSC with budesonide loaded PLGA microparticles. MSC efficiently internalized budesonide microparticles and exhibited 4-fold enhanced IDO activity compared to budesonide preconditioned and naïve MSC, resulting in a 2-fold improvement in suppression of stimulated peripheral blood mononuclear cells in an IDO-dependent manner. Thus, the augmentation of MSC immune modulation may abrogate challenges associated with inadequate potency and enhance their therapeutic efficacy.

REDD1/DDIT4-independent mTORC1 inhibition and apoptosis by glucocorticoids in thymocytes

Glucocorticoids induce apoptosis in lymphocytes and are commonly used to treat hematologic malignancies. However, they are also associated with significant adverse effects and their molecular mechanism of action is not fully understood. Glucocorticoid treatment induces expression of the mTORC1 inhibitor Regulated in Development and DNA Damage Response 1 (REDD1), also known as DNA-Damage Inducible Transcript 4 (DDIT4), and mTORC1 inhibition may distinguish glucocorticoid-sensitive from glucocorticoid-resistant acute lymphoblastic leukemia (ALL). Interestingly, REDD1 induction was impaired in glucocorticoid-resistant ALL cells and inhibition of mTORC1 using rapamycin restored glucocorticoid sensitivity. These data suggest that REDD1 may be essential for the response of ALL cells to glucocorticoids. To further investigate the role of REDD1, we evaluated the effects of glucocorticoids on primary thymocytes from wild-type and REDD1-deficient mice. Glucocorticoid-mediated apoptosis was blocked by a glucocorticoid receptor antagonist and by an inhibitor of transcription, which interfered with REDD1 induction and mTORC1 inhibition. However, REDD1 ablation had no effect on glucocorticoid-induced mTORC1 inhibition and apoptosis in thymocytes ex vivo. Overall, these data not only demonstrate the contextual differences of downstream signaling following glucocorticoid treatment but also provide a better mechanistic understanding of the role of REDD1.

IMPLICATIONS

These molecular findings underlying glucocorticoid action and the role of REDD1 are fundamental for the design of novel, more efficacious, and less toxic analogs. Mol Cancer Res; 12(6); 867-77. ©2014 AACR.