Mechanisms regulating the susceptibility of hematopoietic malignancies to glucocorticoid-induced apoptosis. Adv Cancer Res. 2008;101:127-248. [PMID: 19055945 DOI: 10.1016/s0065-230x(08)00406-5]

Interaction of olive oil-based propolis and caffeic acid phenethyl ester with methylprednisolone used in the treatment of human acute myeloid leukemia

BACKGROUND

Methylprednisolone (MP) is a pharmaceutical agent employed in the management of Leukemia, which is a systemic malignancy that arises from abnormalities in the hematological system. Numerous investigations in the field of cancer research have directed their attention towards propolis, a natural substance with significant potential as a treatment-supportive agent. Its utilization aims to mitigate the potential adverse effects associated with chemotherapy medications. The objective of this study was to examine the impact of olive oil-based propolis (OEP) and caffeic acid phenethyl ester (CAPE) on the treatment of acute myeloid leukemia, as well as to determine if they exhibit a synergistic effect when combined with the therapeutic support product methylprednisolone.

METHODS AND RESULTS

The proliferation of HL-60 cells was quantified using the WST-8 kit. The PI Staining technique was employed to do cell cycle analysis of DNA in cells subjected to OEP, CAPE, and MP, with subsequent measurement by flow cytometry. The apoptotic status of cells was determined by analyzing them using flow cytometry after staining with the Annexin V-APC kit. The quantification of apoptotic gene expression levels was conducted in HL-60 cells. In HL-60 cells, the IC50 dosages of CAPE and MP were determined to be 1 × 10- 6 M and 5 × 10- 4 M, respectively. The HL-60 cells were subjected to apoptosis and halted in the G0/G1 and G2/M phases of the cell cycle after being treated with MP, CAPE, and OEP.

CONCLUSIONS

Propolis and its constituents have the potential to serve as effective adjunctive therapies in chemotherapy.

Identification of Hub Genes Associated with Resistance to Prednisolone in Acute Lymphoblastic Leukemia Based on Weighted Gene Co-expression Network Analysis

Resistance against glucocorticoids which are used to reduce inflammation and treatment of a number of diseases, including leukemia, is known as the first stage of treatment failure in acute lymphoblastic leukemia. Since these drugs are the essential components of chemotherapy regimens for ALL and play an important role in stop of cell growth and induction of apoptosis, it is important to identify genes and the molecular mechanism that may affect glucocorticoid resistance. In this study, we used the GSE66705 dataset and weighted gene co-expression network analysis (WGCNA) to identify modules that correlated more strongly with prednisolone resistance in type B lymphoblastic leukemia patients. The PPI network was built using the DEGs key modules and the STRING database. Finally, we used the overlapping data to identify hub genes. out of a total of 12 identified modules by WGCNA, the blue module was find to have the most statistically significant correlation with prednisolone resistance and Nine genes including SOD1, CD82, FLT3, GART, HPRT1, ITSN1, TIAM1, MRPS6, MYC were recognized as hub genes Whose expression changes can be associated with prednisolone resistance. Enrichment analysis based on the MsigDB repository showed that the altered expressed genes of the blue module were mainly enriched in IL2_STAT5, KRAS, MTORC1, and IL6-JAK-STAT3 pathways, and their expression changes can be related to cell proliferation and survival. The analysis performed by the WGCNA method introduced new genes. The role of some of these genes was previously reported in the resistance to chemotherapy in other diseases. This can be used as clues to detect treatment-resistant (drug-resistant) cases in the early stages of diseases.

European survey on neurosurgical management of primary central nervous system lymphomas and preoperative corticosteroid therapy

Introduction

Preoperative corticosteroid therapy (CST) is common in primary central nervous system lymphoma (PCNSL) and may complicate histopathological diagnosis. There is an ongoing debate on the best management after preoperative CST.

Research question

We aimed to survey how different European neurosurgical units treat PCNSL patients after preoperative CST.

Methods

An English-language survey consisting of 21 questions addressing the management of patients with suspected PCNSL and preoperative CST was sent to European hospitals. The survey also included three clinical cases to assess the decision-making process in a clinical setting.

Results

The survey was completed by 74 European hospitals. There was no clear consensus on how to treat a patient with PCNSL after CST. Accordingly, 24.3% responded that they would generally defer surgery regardless of a possible radiological response, 47.3% would defer surgery only if there is regression in preoperative MRI and the remaining 28.4% would defer surgery only if the tumor had completely vanished. Furthermore, there were distinct discrepancies in responses of neurosurgical units regarding their general management approach and their case-based decision in the three example cases. The results of our survey also showed regional differences and differences in treatment decisions between high-, intermediate- and low-volume centers.

Discussion and conclusion

There was no clear consensus on how to treat patients with suspected PCNSL and preoperative CST. Furthermore, most centers also showed inconsistencies in their responses regarding their general approach as well as individual patient treatment. More high-quality evidence-based recommendations are needed to improve consensus and thus patient care.

An Update on Neurosurgical Management of Primary CNS Lymphoma in Immunocompetent Patients

Primary central nervous system lymphomas (PCNSL) are rare CNS tumors that harbor a conspicuously longer diagnostic delay compared to other malignant brain tumors. The gold standard for diagnosis is stereotactic biopsy to acquire tissue for histopathological analysis and therefore neurosurgery plays a central role when reducing the diagnostic period is mandated. However, histopathological diagnosis could be complicated if the patient was preoperatively exposed to corticosteroids. Besides the histopathological result, diagnosis of a PCNSL also requires full diagnostic workup to exclude cerebral metastatic disease of a systemic lymphoma. Most reviews of PCNSL discuss recent advancements in systemic treatment options from an (neuro-)oncologic viewpoint, whereas our intention was to discuss the optimization of the diagnostic period and therefore describe current standards of imaging, summarizing the diagnostic workup, discussing the surgical workup and future diagnostic prospects as well as the influence of preoperative corticosteroid therapy to reduce the diagnostic delay of PCNSL patients.

Chidamide plus prednisone, etoposide, and thalidomide for untreated angioimmunoblastic T-cell lymphoma in a Chinese population: A multicenter phase II trial

Angioimmunoblastic T‐cell lymphoma (AITL) is a common type of peripheral T‐cell lymphoma (PTCL) with a poor prognosis, and an effective first‐line therapy is lacking. Chidamide is a selective histone deacetylase inhibitor and has been approved by the China Food and Drug Administration for relapsed or refractory PTCL. We conducted a multicenter phase II clinical trial combining chidamide with prednisone, etoposide, and thalidomide (CPET regimen) for a total of eight cycles in untreated AITL patients in China. The primary objectives were the overall response rate (ORR) and complete remission (CR) rate after eight cycles of the CPET regimen. The secondary endpoints were progression‐free survival (PFS) and safety. Of the 71 enrolled patients, 51 completed the eight cycles of the CPET regimen. The ORR and CR of the 51 patients were 90.2 and 54.9%, respectively. After a median follow‐up of 11.4 months (95% confidence interval [CI], 9.9–17.0), the median PFS of the 51 patients was 42.6 months (95% CI, 27.7—not reached) and the median overall survival (OS) was not reached. The 2‐year PFS rate and OS rate were 66.5 and 82.2%, respectively. Sixty‐eight patients received at least one cycle of CPET regimen and were included as the safety assessment population. The most common grade 3/4 adverse event was neutropenia (n = 22, 32.3%). Twelve patients showed treatment‐related infections and recovered from antibiotic therapy; the other adverse events were mostly mild and reversible. The oral CPET regimen is an effective, tolerable, and economical choice for untreated AITL in a Chinese population. This trial was registered in www.clinicaltrials.gov as NCT03273452.

Preparing for CAR T cell therapy: patient selection, bridging therapies and lymphodepletion

Chimeric antigen receptor (CAR) T cells have emerged as a potent therapeutic approach for patients with certain haematological cancers, with multiple CAR T cell products currently approved by the FDA for those with relapsed and/or refractory B cell malignancies. However, in order to derive the desired level of effectiveness, patients need to successfully receive the CAR T cell infusion in a timely fashion. This process entails apheresis of the patient's T cells, followed by CAR T cell manufacture. While awaiting infusion at an authorized treatment centre, patients may receive interim disease-directed therapy. Most patients will also receive a course of pre-CAR T cell lymphodepletion, which has emerged as an important factor in enabling durable responses. The time between apheresis and CAR T cell infusion is often not a simple journey, with each milestone being a critical step that can have important downstream consequences for the ability to receive the infusion and the strength of clinical responses. In this Review, we provide a summary of the many considerations for preparing patients with B cell non-Hodgkin lymphoma or acute lymphoblastic leukaemia for CAR T cell therapy, and outline current limitations and areas for future research.

Crosstalk between p38 MAPK and GR Signaling

The p38 MAPK is a signaling pathway important for cells to respond to environmental and intracellular stress. Upon activation, the p38 kinase phosphorylates downstream effectors, which control the inflammatory response and coordinate fundamental cellular processes such as proliferation, apoptosis, and differentiation. Dysregulation of this signaling pathway has been linked to inflammatory diseases and cancer. Secretion of glucocorticoids (GCs) is a classical endocrine response to stress. The glucocorticoid receptor (GR) is the primary effector of GCs and plays an important role in the regulation of cell metabolism and immune response by influencing gene expression in response to hormone-dependent activation. Its ligands, the GCs or steroids, in natural or synthetic variation, are used as standard therapy for anti-inflammatory treatment, severe asthma, autoimmune diseases, and several types of cancer. Several years ago, the GR was identified as one of the downstream targets of p38, and, at the same time, it was shown that glucocorticoids could influence p38 signaling. In this review, we discuss the role of the crosstalk between the p38 and GR in the regulation of gene expression in response to steroids and comprehend the importance and potential of this interplay in future clinical applications.

Clinical Features and Risk Factors of Severe Pneumonia in Children With Acute Lymphoblastic Leukemia

OBJECTIVE

This study aims to analyze the clinical characteristics of pediatric acute lymphoblastic leukemia (ALL) complicated by pneumonia and the risk factors of severe cases to preliminarily construct a prediction model for ALL complicated by severe pneumonia.

METHODS

A retrospective analysis was carried out on the clinical data of children diagnosed with ALL complicated by pneumonia hospitalized at the Department of Pediatrics of the Affiliated Hospital of Southwest Medical University between January 2013 and December 2020. The risk factors of severe ALL complicated by pneumonia were investigated with logistic regression analysis, and the risk prediction model was constructed.

RESULTS

A total of 116 cases of pediatric ALL complicated by pneumonia were analyzed. There were 71 cases of mild pneumonia and 45 cases of severe pneumonia. The main clinical manifestations were cough in 112 cases and fever in 109. Pathogens were detected in 23 cases. Multiple regression factor analysis indicated that the use of hormones (OR 4.001, 95% CI: 1.505-10.632), neutropenia or agranulocytosis (OR 7.472, 95% CI: 2.710-20.602), hemoglobin (Hb) < 90 g/L (OR 3.270, 95% CI: 1.256~8.516), and C-reactive protein (CRP) >15 mg/L (OR 3.253, 95% CI: 1.209~8.751) were independent risk factors that were associated with severe pneumonia. Logistic regression was used to establish the risk prediction model of ALL with severe pneumonia. The p-value was 0.659. The area under the receiver operating characteristic curve was 0.851, and the sensitivity and specificity were 84.4 and 71.8%, respectively.

CONCLUSION

The development of severe pneumonia may be affected by the use of hormones, neutropenia or agranulocytosis, Hb < 90 g/L, and CRP > 15 mg/L. The prediction model based on the risk factors is effective, which can provide a reference for the clinical evaluation of acute lymphoblastic leukemia with severe pneumonia.

Influence of preoperative corticosteroid treatment on rate of diagnostic surgeries in primary central nervous system lymphoma: a multicenter retrospective study

Background

Corticosteroid therapy (CST) prior to biopsy may hinder histopathological diagnosis in primary central nervous system lymphoma (PCNSL). Therefore, preoperative CST in patients with suspected PCNSL should be avoided if clinically possible. The aim of this study was thus to analyze the difference in the rate of diagnostic surgeries in PCNSL patients with and without preoperative CST.

Methods

A multicenter retrospective study including all immunocompetent patients diagnosed with PCNSL between 1/2004 and 9/2018 at four neurosurgical centers in Austria was conducted and the results were compared to literature.

Results

A total of 143 patients were included in this study. All patients showed visible contrast enhancement on preoperative MRI. There was no statistically significant difference in the rate of diagnostic surgeries with and without preoperative CST with 97.1% (68/70) and 97.3% (71/73), respectively (p = 1.0). Tapering and pause of CST did not influence the diagnostic rate. Including our study, there are 788 PCNSL patients described in literature with an odds ratio for inconclusive surgeries after CST of 3.3 (CI 1.7–6.4).

Conclusions

Preoperative CST should be avoided as it seems to diminish the diagnostic rate of biopsy in PCNSL patients. Yet, if CST has been administered preoperatively and there is still a contrast enhancing lesion to target for biopsy, surgeons should try to keep the diagnostic delay to a minimum as the likelihood for acquiring diagnostic tissue seems sufficiently high.

Inhibition of the NRF2/KEAP1 Axis: A Promising Therapeutic Strategy to Alter Redox Balance of Cancer Cells

Significance: The nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (NRF2/KEAP1) pathway is a crucial and highly conserved defensive system that is required to maintain or restore the intracellular homeostasis in response to oxidative, electrophilic, and other types of stress conditions. The tight control of NRF2 function is maintained by a complex network of biological interactions between positive and negative regulators that ultimately ensure context-specific activation, culminating in the NRF2-driven transcription of cytoprotective genes. Recent Advances: Recent studies indicate that deregulated NRF2 activation is a frequent event in malignant tumors, wherein it is associated with metabolic reprogramming, increased antioxidant capacity, chemoresistance, and poor clinical outcome. On the other hand, the growing interest in the modulation of the cancer cells' redox balance identified NRF2 as an ideal therapeutic target. Critical Issues: For this reason, many efforts have been made to identify potent and selective NRF2 inhibitors that might be used as single agents or adjuvants of anticancer drugs with redox disrupting properties. Despite the lack of specific NRF2 inhibitors still represents a major clinical hurdle, the researchers have exploited alternative strategies to disrupt NRF2 signaling at different levels of its biological activation. Future Directions: Given its dualistic role in tumor initiation and progression, the identification of the appropriate biological context of NRF2 activation and the specific clinicopathological features of patients cohorts wherein its inactivation is expected to have clinical benefits, will represent a major goal in the field of cancer research. In this review, we will briefly describe the structure and function of the NRF2/ KEAP1 system and some of the most promising NRF2 inhibitors, with a particular emphasis on natural compounds and drug repurposing. Antioxid. Redox Signal. 34, 1428-1483.

Glucocorticoid Resistant Pediatric Acute Lymphoblastic Leukemia Samples Display Altered Splicing Profile and Vulnerability to Spliceosome Modulation

Glucocorticoid (GC) resistance is a crucial determinant of inferior response to chemotherapy in pediatric acute lymphoblastic leukemia (ALL); however, molecular mechanisms underlying this phenomenon are poorly understood. Deregulated splicing is a common feature of many cancers, which impacts drug response and constitutes an attractive therapeutic target. Therefore, the aim of the current study was to characterize global splicing profiles associated with GC resistance and determine whether splicing modulation could serve as a novel therapeutic option for GC-resistant patients. To this end, 38 primary ALL samples were profiled using RNA-seq-based differential splicing analysis. The impact of splicing modulators was investigated in GC-resistant leukemia cell lines and primary leukemic specimens. Our findings revealed, for the first time, markedly distinct splicing landscapes in ALL samples of B-cell precursor (BCP)-ALL and T-ALL lineages. Differential splicing events associated with GC resistance were involved in RNA processing, a direct response to GCs, survival signaling, apoptosis, cell cycle regulation and energy metabolism. Furthermore, our analyses showed that GC-resistant ALL cell lines and primary samples are sensitive to splicing modulation, alone and in combination with GC. Together, these findings suggest that aberrant splicing is associated with GC resistance and splicing modulators deserve further interest as a novel treatment option for GC-resistant patients.

Emerging Role of Podocalyxin in the Progression of Mature B-Cell Non-Hodgkin Lymphoma

Mature B-cell non-Hodgkin lymphoma (B-NHL) constitutes a group of heterogeneous malignant lymphoproliferative diseases ranging from indolent to highly aggressive forms. Although the survival after chemo-immunotherapy treatment of mature B-NHL has increased over the last years, many patients relapse or remain refractory due to drug resistance, presenting an unfavorable prognosis. Hence, there is an urgent need to identify new prognostic markers and therapeutic targets. Podocalyxin (PODXL), a sialomucin overexpressed in a variety of tumor cell types and associated with their aggressiveness, has been implicated in multiple aspects of cancer progression, although its participation in hematological malignancies remains unexplored. New evidence points to a role for PODXL in mature B-NHL cell proliferation, survival, migration, drug resistance, and metabolic reprogramming, as well as enhanced levels of PODXL in mature B-NHL. Here, we review the current knowledge on the contribution of PODXL to tumorigenesis, highlighting and discussing its role in mature B-NHL progression.

Efficacy of a Second Brain Biopsy for Intracranial Lesions after Initial Negativity

Background and Purpose

The rationale for performing a second brain biopsy after initial negativity is not well evaluated in the literature. This study was designed to 1) assess the efficacy of a second brain biopsy when the first biopsy was nondiagnostic, 2) identify possible factors associated with an increased diagnostic rate in the second biopsy, and 3) analyze additional morbidity induced by the second biopsy.

Methods

We performed a retrospective cohort study from 2009 to 2019, during which 1,919 patients underwent a brain biopsy, including 30 who were biopsied twice (1.6%). The specific histological diagnosis rate, diagnosis-associated factors, and complication rate were assessed for the 30 twice-biopsied patients.

Results

The second biopsy allowed a specific histological diagnosis in 86.7% of the patients who had initially undergone a nondiagnostic brain biopsy [odds ratio (OR)=7.5, 95% confidence interval (CI)=3.0–18.7, p<0.001]. The multivariate analysis showed that only prebiopsy corticosteroid administration (OR=2.6, 95% CI=1.1–6.0, p=0.01) was an important factor in predicting a nondiagnostic biopsy. None of the patients developed a symptomatic complication after the first biopsy, while two (6.0%) patients experienced a transient complication after the second biopsy (p=0.49).

Conclusions

Performing a second brain biopsy in patients who have an initial nondiagnostic biopsy is effective in most cases. We advocate that a second biopsy be systematically considered in the diagnosis algorithm of these patients after it has been verified that molecular testing cannot help to obtain a diagnosis. Corticosteroid administration can lead to nondiagnostic biopsies and should be avoided when possible during the prebiopsy period.

Corticosteroid-Induced Regression of Glioblastoma: A Radiographic Conundrum

Corticosteroid-induced regression of lesion contrast enhancement on imaging studies is most commonly appreciated with primary central nervous system lymphoma; however, although exceedingly rare, a limited number of primary and metastatic intracranial lesions have been reported to exhibit similar radiographic changes subsequent to corticosteroid therapy. To date, there have been six cases of glioblastoma reported to exhibit such changes. Lesion transformation on repeat imaging after the initiation of steroids represents a diagnostic dilemma for clinicians when attempting to differentiate between a diagnosis of glioblastoma and lymphoma. Stereotactic biopsy may be inadvertently postponed due to high clinical suspicion for steroid-induced cytotoxicity traditionally seen with lymphomatous cells. To highlight this radiographic conundrum, we present a rare case of corticosteroid-induced regression of glioblastoma and discuss the relevant literature. To our knowledge, this is the first case report to describe the molecular profile of a glioblastoma that underwent corticosteroid-induced regression.

Screening a library of approved drugs reveals that prednisolone synergizes with pitavastatin to induce ovarian cancer cell death

The survival rate for patients with ovarian cancer has changed little in the past three decades since the introduction of platinum-based chemotherapy and new drugs are needed. Statins are drugs used for the treatment and prevention of cardiovascular diseases. Recent work from our laboratory has shown that pitavastatin has potential as a treatment for ovarian cancer if dietary geranylgeraniol is controlled. However, relatively high doses of statins are required to induce apoptosis in cancer cells, increasing the risk of myopathy, the most common adverse effect associated with statins. This makes it desirable to identify drugs which reduce the dose of pitavastatin necessary to treat cancer. A drug-repositioning strategy was employed to identify suitable candidates. Screening a custom library of 100 off-patent drugs for synergistic activity with pitavastatin identified prednisolone as the most prominent hit. Prednisolone potentiated the activity of pitavastatin in several assays measuring the growth, survival or apoptosis in several ovarian cancer cells lines. Prednisolone, alone or in some cases in combination with pitavastatin, reduced the expression of genes encoding enzymes in the mevalonate pathway, providing a mechanistic explanation for the synergy.

Intrathecal betamethasone for cancer pain: A study of its analgesic efficacy and safety

BACKGROUND

A preliminary study has shown effective cancer pain relief by intrathecal betamethasone (ITB). However, further evidence is needed to support this new approach.

METHODS

Cancer patients with opioid-resistant pain received lumbar intrathecal administration of betamethasone 2 or 3 mg once a week for 28 days. Immediate and short-term analgesia (using a percentage pain reduction scale and a numerical rating scale, NRS) and long-term analgesia (using NRS) were assessed. Patients were classified into two groups according to the most painful site of metastasis: vertebral column and/or surrounding nerve plexus metastases (group A) and other metastases distal from the vertebral column (group B).

RESULTS

A total of 104 patients received ITB. Pain relief was observed not only in the lower half but also in the upper half of the body. The proportion of group A patients who experienced immediate analgesia was 81% (47/58), which was significantly greater than that of group B (P < 0.001). A decrease in NRS scores 1 day after ITB administration was observed in significantly more patients in group A than in group B (P < 0.001). Long-term analgesia was also recorded in a greater proportion of patients in group A than in group B in the 7-day (59%, 38/64 vs 6%, 2/33) and 28-day periods (71%, 40/56 vs 31%, 8/26) (P < 0.001). No adverse effects related to neurotoxicity were recorded.

CONCLUSION

Intrathecal injection of betamethasone produced analgesia for opioid-resistant cancer pain, and may be a potent therapeutic option for intolerable pain from vertebral column and/or surrounding nerve plexus metastases.

Peroxisome Proliferator-Activated Receptors (PPAR)γ Agonists as Master Modulators of Tumor Tissue

In most clinical trials, thiazolidinediones do not show any relevant anti-cancer activity when used as mono-therapy. Clinical inefficacy contrasts ambiguous pre-clinical data either favoring anti-tumor activity or tumor promotion. However, if thiazolidinediones are combined with additional regulatory active drugs, so-called ‘master modulators’ of tumors, i.e., transcriptional modulators, metronomic low-dose chemotherapy, epigenetically modifying agents, protein binding pro-anakoinotic drugs, such as COX-2 inhibitors, IMiDs, etc., the results indicate clinically relevant communicative reprogramming of tumor tissues, i.e., anakoinosis, meaning ‘communication’ in ancient Greek. The concerted activity of master modulators may multifaceted diversify palliative care or even induce continuous complete remission in refractory metastatic tumor disease and hematologic neoplasia by establishing novel communicative behavior of tumor tissue, the hosting organ, and organism. Re-modulation of gene expression, for example, the up-regulation of tumor suppressor genes, may recover differentiation, apoptosis competence, and leads to cancer control—in contrast to an immediate, ‘poisoning’ with maximal tolerable doses of targeted/cytotoxic therapies. The key for uncovering the therapeutic potential of Peroxisome proliferator-activated receptor γ (PPARγ) agonists is selecting the appropriate combination of master modulators for inducing anakoinosis: Now, anakoinosis is trend setting by establishing a novel therapeutic pillar while overcoming classic obstacles of targeted therapies, such as therapy resistance and (molecular-)genetic tumor heterogeneity.

miR-103 inhibits proliferation and sensitizes hemopoietic tumor cells for glucocorticoid-induced apoptosis

Glucocorticoid (GC) hormones are an important ingredient of leukemia therapy since they are potent inducers of lymphoid cell apoptosis. However, the development of GC resistance remains an obstacle in GC-based treatment. In the present investigation we found that miR-103 is upregulated in GC-sensitive leukemia cells treated by the hormone. Transfection of GC resistant cells with miR-103 sensitized them to GC induced apoptosis (GCIA), while miR-103 sponging of GC sensitive cells rendered them partially resistant. miR-103 reduced the expression of cyclin dependent kinase (CDK2) and its cyclin E1 target, thereby leading to inhibition of cellular proliferation. miR-103 is encoded within the fifth intron of PANK3 gene. We demonstrate that the GC receptor (GR) upregulates miR-103 by direct interaction with GC response element (GRE) in the PANK3 enhancer. Consequently, miR-103 targets the c-Myc activators c-Myb and DVL1, thereby reducing c-Myc expression. Since c-Myc is a transcription factor of the miR-17~92a poly-cistron, all six miRNAs of the latter are also downregulated. Of these, miR-18a and miR-20a are involved in GCIA, as they target GR and BIM, respectively. Consequently, GR and BIM expression are elevated, thus advancing GCIA. Altogether, this study highlights miR-103 as a useful prognostic biomarker and drug for leukemia management in the future.

Podocalyxin promotes proliferation and survival in mature B-cell non-Hodgkin lymphoma cells

Podocalyxin (PCLP1) is a CD34-related sialomucin expressed by some normal cells and a variety of malignant tumors, including leukemia, and associated with the most aggressive cancers and poor clinical outcome. PCLP1 increases breast tumor growth, migration and invasion; however, its role in hematologic malignancies still remains undetermined. The purpose of this study was to investigate the expression and function of PCLP1 in mature B-cell lymphoma cells. We found that overexpression of PCLP1 significantly increases proliferation, cell-to-cell interaction, clonogenicity, and migration of B-cell lymphoma cells. Furthermore, PCLP1 overexpression results in higher resistance to death induced by dexamethasone, reactive oxygen species and type II anti-CD20 monoclonal antibody obinutuzumab. Strikingly, enforced expression of PCLP1 enhances lipid droplet formation as well as pentose phosphate pathway and glutamine dependence, indicative of metabolic reprogramming necessary to support the abnormal proliferation rate of tumor cells. Flow cytometry analysis revealed augmented levels of PCLP1 in malignant cells from some patients with mature B-cell lymphoma compared to their normal B-cell counterparts. In summary, our results demonstrate that PCLP1 contributes to proliferation and survival of mature B-cell lymphoma cells, suggesting that PCLP1 may promote lymphomagenesis and represents a therapeutic target for the treatment of B-cell lymphomas.

Differential regulation of cell death pathways by the microenvironment correlates with chemoresistance and survival in leukaemia

Glucocorticoids (GCs) and topoisomerase II inhibitors are used to treat acute lymphoblastic leukaemia (ALL) as they induce death in lymphoid cells through the glucocorticoid receptor (GR) and p53 respectively. Mechanisms underlying ALL cell death and the contribution of the bone marrow microenvironment to drug response/resistance remain unclear. The role of the microenvironment and the identification of chemoresistance determinants were studied by transcriptomic analysis in ALL cells treated with Dexamethasone (Dex), and Etoposide (Etop) grown in the presence or absence of bone marrow conditioned media (CM). The necroptotic (RIPK1) and the apoptotic (caspase-8/3) markers were downregulated by CM, whereas the inhibitory effects of chemotherapy on the autophagy marker Beclin-1 (BECN1) were reduced suggesting CM exerts cytoprotective effects. GCs upregulated the RIPK1 ubiquitinating factor BIRC3 (cIAP2), in GC-sensitive (CEM-C7-14) but not in resistant (CEM-C1-15) cells. In addition, CM selectively affected GR phosphorylation in a site and cell-specific manner. GR is recruited to RIPK1, BECN1 and BIRC3 promoters in the sensitive but not in the resistant cells with phosphorylated GR forms being generally less recruited in the presence of hormone. FACS analysis and caspase-8 assays demonstrated that CM promoted a pro-survival trend. High molecular weight proteins reacting with the RIPK1 antibody were modified upon incubation with the BIRC3 inhibitor AT406 in CEM-C7-14 cells suggesting that they represent ubiquitinated forms of RIPK1. Our data suggest that there is a correlation between microenvironment-induced ALL proliferation and altered response to chemotherapy.

Sensitization of retinoids and corticoids to epigenetic drugs in MYC-activated lung cancers by antitumor reprogramming

Components of the SWI/SNF chromatin remodeling complex, including BRG1 (also SMARCA4), are inactivated in cancer. Among other functions, SWI/SNF orchestrates the response to retinoid acid (RA) and glucocorticoids (GC) involving downregulation of MYC. The epigenetic drugs SAHA and azacytidine, as well as RA and GC, are currently being used to treat some malignancies but their therapeutic potential in lung cancer is not well established. Here we aimed to determine the possible therapeutic effects of azacytidine and SAHA (A/S) alone or in combination with GC plus RA (GC/RA) in lung cancers with either BRG1 inactivation or MYC amplification. In vitro, responses to GC/RA treatment were more effective in MYC-amplified cells. These effects were mediated by BRG1 and involved a reprogramming towards prodifferentiation gene expression signatures and downregulation of MYC. In MYC-amplified cells, administration of GC/RA enhanced the cell growth inhibitory effects of A/S which, in turn, accentuated the prodifferentiation features promoted by GC/RA. Finally, these treatments improved overall survival of mice orthotopically implanted with MYC-amplified, but not BRG1-mutant, cells and reduced tumor cell viability and proliferation. We propose that the combination of epigenetic treatments with retinoids and corticoids of MYC-driven lung tumors constitute a strategy for therapeutic intervention in this otherwise incurable disease.

Selective glucocorticoid receptor-activating adjuvant therapy in cancer treatments

Although adverse effects and glucocorticoid resistance cripple their chronic use, glucocorticoids form the mainstay therapy for acute and chronic inflammatory disorders, and play an important role in treatment protocols of both lymphoid malignancies and as adjuvant to stimulate therapy tolerability in various solid tumors. Glucocorticoid binding to their designate glucocorticoid receptor (GR), sets off a plethora of cell-specific events including therapeutically desirable effects, such as cell death, as well as undesirable effects, including chemotherapy resistance, systemic side effects and glucocorticoid resistance. In this context, selective GR agonists and modulators (SEGRAMs) with a more restricted GR activity profile have been developed, holding promise for further clinical development in anti-inflammatory and potentially in cancer therapies. Thus far, the research into the prospective benefits of selective GR modulators in cancer therapy limped behind. Our review discusses how selective GR agonists and modulators could improve the therapy regimens for lymphoid malignancies, prostate or breast cancer. We summarize our current knowledge and look forward to where the field should move to in the future. Altogether, our review clarifies novel therapeutic perspectives in cancer modulation via selective GR targeting.

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.

Prednisolone inhibits SaOS2 osteosarcoma cell proliferation by activating inducible nitric oxide synthase

AIM: To investigate the effect of prednisolone, a synthetic glucocorticoid used in inflammatory diseases, on the growth of cultured osteosarcoma cells.

METHODS: Two osteosarcoma cell lines with different degree of differentiation were used. SaOS2 show a rather mature phenotype, while U2OS are negative for almost all osteoblastic markers. The cells were exposed to different concentrations of prednisolone (1-9 μmol/L) with or without antioxidants or the inhibitor of inducible nitric oxide synthase (iNOS) l-N⁶-(iminoethyl)-lysine-HCl (L-NIL). Cell growth was assessed by counting viable cells. The production of nitric oxide (NO) was measured in the conditioned media by the Griess method. The production of reactive oxygen species was quantified using 2’-7’-dichlorofluorescein diacetate. Western blot with specific antibodies against NOSs was performed on cell extracts.

RESULTS: Prednisolone inhibited SaOS2 cell growth in a dose dependent manner. No significant effects were observed in U2OS. The inhibition of SaOS2 growth is not due to oxidative stress, because antioxidants do not rescue cell proliferation. Since high concentrations of NO inhibit bone formation, we also measured NO and found it induced in SaOS2, but not in U2OS, exposed to prednisolone, because of the upregulation of iNOS as detected by western blot. Therefore, we treated SaOS2 with prednisolone in the presence or in the absence of L-NIL. L-NIL prevented NO release induced by prednisolone at all the concentrations apart from 9 μmol/L. At the same concentrations, we found that L-NIL rescued SaOS2 growth after exposure to prednisolone. In U2OS cells, prednisolone did not induce NO production nor affected cell growth. All together, these data indicate that a link exists between increased amounts of NO and growth inhibition in response to prednisolone in SaOS2.

CONCLUSION: Prednisolone inhibited SaOS2 proliferation by increasing the release of NO through the upregulation of iNOS, while no effect was exerted on U2OS.

Inhibition of autophagy overcomes glucocorticoid resistance in lymphoid malignant cells

Glucocorticoid (GC) resistance remains a major obstacle to successful treatment of lymphoid malignancies. Till now, the precise mechanism of GC resistance remains unclear. In the present study, dexamethasone (Dex) inhibited cell proliferation, arrested cell cycle in G0/G1-phase, and induced apoptosis in Dex-sensitive acute lymphoblastic leukemia cells. However, Dex failed to cause cell death in Dex-resistant lymphoid malignant cells. Intriguingly, we found that autophagy was induced by Dex in resistant cells, as indicated by autophagosomes formation, LC3-I to LC3-II conversion, p62 degradation, and formation of acidic autophagic vacuoles. Moreover, the results showed that Dex reduced the activity of mTOR pathway, as determined by decreased phosphorylation levels of mTOR, Akt, P70S6K and 4E-BP1 in resistant cells. Inhibition of autophagy by either chloroquine (CQ) or 3-methyladenine (3-MA) overcame Dex-resistance in lymphoid malignant cells by increasing apoptotic cell death in vitro. Consistently, inhibition of autophagy by stably knockdown of Beclin1 sensitized Dex-resistant lymphoid malignant cells to induction of apoptosis in vivo. Thus, inhibition of autophagy has the potential to improve lymphoid malignancy treatment by overcoming GC resistance.

Effect of cAMP signaling on expression of glucocorticoid receptor, Bim and Bad in glucocorticoid-sensitive and resistant leukemic and multiple myeloma cells

Stimulation of cAMP signaling induces apoptosis in glucocorticoid-sensitive and resistant CEM leukemic and MM.1 multiple myeloma cell lines, and this effect is enhanced by dexamethasone in both glucocorticoid-sensitive cell types and in glucocorticoid-resistant CEM cells. Expression of the mRNA for the glucocorticoid receptor alpha (GR) promoters 1A3, 1B and 1C, expression of mRNA and protein for GR, and the BH3-only proapoptotic proteins, Bim and Bad, and the phosphorylation state of Bad were examined following stimulation of the cAMP and glucocorticoid signaling pathways. Expression levels of GR promoters were increased by cAMP and glucocorticoid signaling, but GR protein expression was little changed in CEM and decreased in MM.1 cells. Stimulation of these two signaling pathways induced Bim in CEM cells, induced Bad in MM.1 cells, and activated Bad, as indicated by its dephosphorylation on ser112, in both cell types. This study shows that leukemic and multiple myeloma cells, including those resistant to glucocorticoids, can be induced to undergo apoptosis by stimulating the cAMP signaling pathway, with enhancement by glucocorticoids, and the mechanism by which this occurs may be related to changes in Bim and Bad expression, and in all cases, to activation of Bad.

Regulation of Bim in Health and Disease

The BH3-only Bim protein is a major determinant for initiating the intrinsic apoptotic pathway under both physiological and pathophysiological conditions. Tight regulation of its expression and activity at the transcriptional, translational and post-translational levels together with the induction of alternatively spliced isoforms with different pro-apoptotic potential, ensure timely activation of Bim. Under physiological conditions, Bim is essential for shaping immune responses where its absence promotes autoimmunity, while too early Bim induction eliminates cytotoxic T cells prematurely, resulting in chronic inflammation and tumor progression. Enhanced Bim induction in neurons causes neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's diseases. Moreover, type I diabetes is promoted by genetically predisposed elevation of Bim in β-cells. On the contrary, cancer cells have developed mechanisms that suppress Bim expression necessary for tumor progression and metastasis. This review focuses on the intricate network regulating Bim activity and its involvement in physiological and pathophysiological processes.

The effects of Jieduquyuzishen prescription-treated rat serum on the BAFF/BAFF-R signal pathway

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease mainly characterized by B cell hyperactivity. Glucocorticoid (GC) is widely used in SLE for its potent anti-inflammatory and immunosuppressive effects. Despite its important clinical efficacy, high-dose or long-term use of GC can cause severe side effects, such as osteoporosis, osteonecrosis, cataracts, hyperglycemia, coronary heart disease and cognitive impairment. Our early clinical studies have shown that Jieduquyuzishen prescription (JP) can effectively reduce the adverse effects and improve the curative effect of GC in the treatment of SLE. The BAFF/BAFF-R signaling pathway plays an important role in the development of SLE and has been regarded as a potential target for the therapy of SLE. In this study, we attempt to investigate the effect of JP on the BAFF/BAFF-R signaling pathway to explore the mechanism of JP in reducing the toxicity and enhancing the efficacy of GC. YAC-1 cells, isolated rat peripheral blood lymphocytes, polymorphonuclear neutrophils and spleen lymphocytes were treated with drug-containing serum. The results of RT-PCR, Western blot and dual-luciferase reporter gene assays indicate that either JP or GC can inhibit the mBAFF-induced up-regulation of BAFF, BAFF-R, Bcl-2, IL-10 and NF-κB in YAC-1 cells and WEHI-231 cells. Furthermore, MTS, flow cytometry and CFSE results reveal that the proliferation and survival of lymphocytes activated by mBAFF are suppressed by JP, GC and their combination. Contrary to GC, JP can reduce the apoptosis and raise the survival of polymorphonuclear neutrophils and can’t increase the apoptosis of the peripheral blood lymphocytes and spleen lymphocytes. Therefore, it is possible that JP can down-regulate the BAFF/BAFF-R signaling pathway as effectively as GC, which may result in the dosage reduction of GC, thus decreasing the toxicity and improving the efficacy of GC-based treatment of SLE.

Identifying anti-growth factors for human cancer cell lines through genome-scale metabolic modeling

Human cancer cell lines are used as important model systems to study molecular mechanisms associated with tumor growth, hereunder how genomic and biological heterogeneity found in primary tumors affect cellular phenotypes. We reconstructed Genome scale metabolic models (GEMs) for eleven cell lines based on RNA-Seq data and validated the functionality of these models with data from metabolite profiling. We used cell line-specific GEMs to analyze the differences in the metabolism of cancer cell lines, and to explore the heterogeneous expression of the metabolic subsystems. Furthermore, we predicted 85 antimetabolites that can inhibit growth of, or even kill, any of the cell lines, while at the same time not being toxic for 83 different healthy human cell types. 60 of these antimetabolites were found to inhibit growth in all cell lines. Finally, we experimentally validated one of the predicted antimetabolites using two cell lines with different phenotypic origins, and found that it is effective in inhibiting the growth of these cell lines. Using immunohistochemistry, we also showed high or moderate expression levels of proteins targeted by the validated antimetabolite. Identified anti-growth factors for inhibition of cell growth may provide leads for the development of efficient cancer treatment strategies.

Glucocorticoids and Cancer

Unlike other steroid hormone receptors, the glucocorticoid receptor (GR) is not considered an oncogene. In breast cancer, the estrogen receptor (ER) drives cell growth, proliferation, and metastasis, and the androgen receptor (AR) plays a similar role in prostate cancer. Accordingly, treatment of these diseases has focused on blocking steroid hormone receptor function. In contrast, glucocorticoids (GCs) work through GR to arrest growth and induce apoptosis in lymphoid tissue. Glucocorticoids are amazingly effective in this role, and have been deployed as the cornerstone of lymphoid cancer treatment for decades. Unfortunately, not all patients respond to GCs and dosage is restricted by immediate and long term side effects. In this chapter we review the treatment protocols that employ glucocorticoids as a curative agent, elaborate on what is known about their mechanism of action in these cancers, and also summarize the palliative uses of glucocorticoids for other cancers.

Synergistic Anti-Tumor Activity of EZH2 Inhibitors and Glucocorticoid Receptor Agonists in Models of Germinal Center Non-Hodgkin Lymphomas

Patients with non-Hodgkin lymphoma (NHL) are treated today with a cocktail of drugs referred to as CHOP (Cyclophosphamide, Hydroxyldaunorubicin, Oncovin, and Prednisone). Subsets of patients with NHL of germinal center origin bear oncogenic mutations in the EZH2 histone methyltransferase. Clinical testing of the EZH2 inhibitor EPZ-6438 has recently begun in patients. We report here that combining EPZ-6438 with CHOP in preclinical cell culture and mouse models results in dramatic synergy for cell killing in EZH2 mutant germinal center NHL cells. Surprisingly, we observe that much of this synergy is due to Prednisolone - a glucocorticoid receptor agonist (GRag) component of CHOP. Dramatic synergy was observed when EPZ-6438 is combined with Prednisolone alone, and a similar effect was observed with Dexamethasone, another GRag. Remarkably, the anti-proliferative effect of the EPZ-6438+GRag combination extends beyond EZH2 mutant-bearing cells to more generally impact germinal center NHL. These preclinical data reveal an unanticipated biological intersection between GR-mediated gene regulation and EZH2-mediated chromatin remodeling. The data also suggest the possibility of a significant and practical benefit of combining EZH2 inhibitors and GRag that warrants further investigation in a clinical setting.

In vivo model for mastocytosis: A comparative review

Human mastocytosis are heterogeneous group of neoplastic diseases characterized by a different degree of uncontrolled mast cell (MC) proliferation and activation. Interestingly, human mastocytosis share several biological and clinical features with canine mast cell disorders, so called canine mast cell tumors (CMCTs). These CMCTs are the most common spontaneous cutaneous tumors found in dogs representing a valid model to study neoplastic mast cell disorders. It has been discovered that the pathological activation of c-Kit receptor (c-KitR), expressed by MCs, has been involved in the pathogenesis of neoplastic MC disorders. In this review we have focused on human mastocytosis in terms of: (i) epidemiology and classification; (ii) pathogenesis at molecular levels; (iii) clinical presentation. In addition, we have summarized animal models useful to study neoplastic MC disorders including CMCTs and murine transgenic models. Finally, we have revised therapeutic approaches mostly common in human and canine MCTs and novel tyrosine kinase inhibitors approved for CMCTs and recently translated in human clinical trials.

Corticosteroid use in neuro-oncology: an update

Because of the lack of curative approaches for most patients with malignant brain tumors, supportive therapy, which aims at maintaining quality of life and functional independence, has a central role in the treatment of many patients. Steroids are particularly important in the setting of supportive therapy. They are commonly used to treat tumor-associated edema, and their administration is typically associated with rapid symptom relief, such as the resolution of headaches. Besides their antiedema activity, corticosteroids are characterized by their potent antilymphoma properties and their effects against acute or delayed emesis caused by systemic chemotherapy in cancer patients. Accordingly, steroids are among the most frequently used drugs in oncology. These desirable properties of steroids are counterbalanced by cardiovascular, muscular, and psychiatric side effects. On the cellular level, corticosteroids exert various effects that translate into the desired clinical activity, but they also evoke significant toxicity that may outweigh the beneficial effects. The mode of action and the limitations of steroid treatment are summarized in this review article. Interactions between steroids and other drugs must be considered. A particular challenge to the ongoing use of glucocorticoids is that newer therapeutic approaches are being introduced in neuro-oncology for which concomitant steroids are likely to be contraindicated. These include the emergence of various immunotherapeutic approaches including vaccination strategies and treatment with immune checkpoint inhibitors. Since the administration of steroids may interfere with the activity of these novel therapies, an even more critical evaluation of their use will be required.

Smac mimetic and glucocorticoids synergize to induce apoptosis in childhood ALL by promoting ripoptosome assembly

Apoptosis resistance contributes to poor outcome in pediatric acute lymphoblastic leukemia (ALL). Here, we identify a novel synergistic combination of Smac mimetic BV6 and glucocorticoids (GCs) (ie, dexamethasone, prednisolone) to trigger apoptosis in ALL cells. BV6 and GCs similarly cooperate to induce apoptosis in patient-derived leukemia samples, underlining the clinical relevance. Importantly, BV6/dexamethasone cotreatment is significantly more effective than monotherapy to delay leukemia growth in a patient-derived xenograft model of pediatric ALL without causing additional side effects. In contrast, BV6 does not increase cytotoxicity of dexamethasone against nonmalignant peripheral blood lymphocytes, mesenchymal stromal cells, and CD34-positive hematopoietic cells. We identify a novel mechanism by showing that BV6 and dexamethasone cooperate to deplete cIAP1, cIAP2, and XIAP, thereby promoting assembly of the ripoptosome, a RIP1/FADD/caspase-8-containing complex. This complex is critical and is required for BV6/dexamethasone-induced cell death, because RIP1 knockdown reduces caspase activation, reactive oxygen species production, and cell death. Ripoptosome formation occurs independently of autocrine/paracrine loops of death receptor ligands, because blocking antibodies for TNFα, tumor necrosis factor-related apoptosis-inducing ligand, or CD95 ligand or knockdown of death receptors fail to rescue BV6/dexamethasone-induced cell death. This is the first report showing that BV6 sensitizes for GC-triggered cell death by promoting ripoptosome formation with important implications for apoptosis-targeted therapies of ALL.

EMP1, a novel poor prognostic factor in pediatric leukemia regulates prednisolone resistance, cell proliferation, migration and adhesion

Still 20% of pediatric acute lymphoblastic leukemia (ALL) patients relapse on or after current treatment strategies. Treatment failure is associated with resistance to prednisolone. We aimed to find new druggable targets that modulate prednisolone resistance. We generated microarray gene expression profiles of 256 pediatric ALL patient samples and identified a 3.4-fold increase in epithelial membrane protein 1 (EMP1) expression in in vitro prednisolone-resistant compared with -sensitive patients (P=0.003). EMP1 silencing in six precursor-B ALL (BCP-ALL) and T-ALL cell lines induced apoptosis and cell-cycle arrest leading to 84.1±4.5% reduction in survival compared with non-silencing control transduced cells (non-silencing control short hairpin, shNSC) (P=0.014). Moreover, EMP1 silencing sensitized to prednisolone up to 18.8-fold (P<0.001). EMP1 silencing also abrogated migration and adhesion to mesenchymal stromal cells (MSCs) by 78.3±9.0 and 29.3±4.1% compared with shNSC (P<0.05). We discovered that EMP1 contributes to MSC-mediated prednisolone resistance. Pathway analysis indicated that EMP1 signals through the Src kinase family. EMP1-high BCP-ALL patients showed a poorer 5-year event-free survival compared with EMP1-low patients (77±2 vs. 89±2%, P=0.003). Multivariate analysis taking along white blood cell count, age, prednisolone resistance and subtype identified EMP1 as an independent predictor for poor outcome in BCP-ALL (P=0.004, hazard ratio: 2.36 (1.31-4.25). This study provides preclinical evidence that EMP1 is an interesting candidate for drug development to optimize treatment of BCP-ALL.

Non-genomic events determining the sensitivity of hemopoietic malignancies to glucocorticoid-induced apoptosis

Glucocorticoid (GC) hormones have been introduced as therapeutic agents in blood cancers six decades ago. The effectiveness of GC treatment stems from its ability to induce apoptotic death of hemopoietic cells. A major impediment in GC therapy is the acquisition of resistance to the drug upon repeated treatment. In addition, some blood cancers are a priori resistant to GC therapy. Usually, resistance to GC correlates with poor prognosis. Albeit the wide use of GC in clinical practice, their mode of action is not fully understood. The cellular response to GC is initiated by its binding to the cytosolic GC receptor (GR) that translocates to the nucleus and modulates gene expression. However, nuclear activities of GR occur in both apoptosis-sensitive and apoptosis-resistant cells. These apparent controversies can be resolved by deciphering non-genomic effects of GCs and the mode by which they modulate the apoptotic response. We suggest that non-genomic consequences of GC stimulation determine the cell fate toward survival or death. Understanding the cellular mechanisms of GC apoptotic sensitivity contributes to the development of new modalities for overcoming GC resistance.

Psychosocial factors and hematopoietic stem cell transplantation: potential biobehavioral pathways

While psychosocial factors are known to affect cancer progression via biobehavioral pathways in many patient populations, these relationships remain largely unexplored in hematopoietic stem cell transplant (HCT) patients. The purpose of this paper is to critically review the literature regarding psychosocial and endocrine/immune aspects of HCT, with an emphasis on exploring pathways that may mediate the associations between psychosocial factors and disease outcomes. These include the roles of catecholamines, glucocorticoids, inflammation, vascular endothelial growth factor (VEGF), immune reconstitution and infectious susceptibility, as well as the new opportunities available in genomics research. We also discuss the implications for potential immunomodulating psychosocial interventions. Elucidating the biological pathways that account for the associations between psychosocial factors and clinical course could ultimately lead to improved outcomes for this psychologically and immunologically vulnerable population.

Deregulated MIR335 that targets MAPK1 is implicated in poor outcome of paediatric acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) is the most common paediatric malignancy. Although 90% of patients are now long-term survivors, the remaining 10% have poor outcome predominantly due to drug resistance. In this study, we carried out genome-wide microRNA (miRNA) microarray analysis on diagnostic bone marrow samples to determine miRNA expression profiles associated with poor outcome in ALL. A reduced expression of MIR335 was identified as the most significant miRNA abnormality associated with poor outcome. It is well known that glucocorticoid (GC) resistance is one of the major reasons contributing to poor outcome. We show that exogenous expression of MIR335 in ALL cells increases sensitization to prednisolone-mediated apoptosis. Moreover, we demonstrate that MAPK1 is a novel target of MIR335, and that MEK/ERK inhibitor treatment enhanced prednisolone-induced cell death through the activation of BIM (BCL2L11). These results provide a possible underlying molecular mechanism to explain the association between reduced MIR335 with poor clinical outcome, and suggest that approaches to re-introduce MIR335 expression or override MAPK1 activity may offer promising therapeutic strategies in the treatment of ALL.

Tissue-specific actions of glucocorticoids on apoptosis: a double-edged sword

First described for their metabolic and immunosuppressive effects, glucocorticoids are widely prescribed in clinical settings of inflammation. However, glucocorticoids are also potent inducers of apoptosis in many cell types and tissues. This review will focus on the established mechanisms of glucocorticoid-induced apoptosis and outline what is known about the apoptotic response in cells and tissues of the body after exposure to glucocorticoids. Glucocorticoid-induced apoptosis affects the skeletal system, muscular system, circulatory system, nervous system, endocrine system, reproductive system, and the immune system. Interestingly, several cell types have an anti-apoptotic response to glucocorticoids that is cytoprotective. Lastly, we will discuss the pro- and anti-apoptotic effects of glucocorticoids in cancers and their clinical implications.

MicroRNAs and Glucocorticoid-Induced Apoptosis in Lymphoid Malignancies

The initial response of lymphoid malignancies to glucocorticoids (GCs) is a critical parameter predicting successful treatment. Although being known as a strong inducer of apoptosis in lymphoid cells for almost a century, the signaling pathways regulating the susceptibility of the cells to GCs are only partly revealed. There is still a need to develop clinical tests that can predict the outcome of GC therapy. In this paper, I discuss important parameters modulating the pro-apoptotic effects of GCs, with a specific emphasis on the microRNA world comprised of small players with big impacts. The journey through the multifaceted complexity of GC-induced apoptosis brings forth explanations for the differential treatment response and raises potential strategies for overcoming drug resistance.

11β-Hydroxysteroid Dehydrogenase Type II is a Potential Target for Prevention of Colorectal Tumorigenesis

Colorectal cancer (CRC) is a leading cause of cancer death, yet primary prevention remains the best approach to reducing overall morbidity and mortality. There is a clear molecular link between cyclooxygenase-2 (COX-2)-derived prostaglandin E₂ (PGE₂) production and CRC progression. Although selective COX-2 inhibitors as well as non-steroidal anti-inflammatory drugs (NSAIDs) reduce the number and sizes of colonic adenomas, increased cardiovascular risks of selective COX-2 inhibitors and increased gastrointestinal side-effects of NSAIDs limit their use in chemoprevention of CRC. Glucocorticoids induce apoptosis and are endogenous, potent COX-2 inhibitors. Glucocorticoids have been used for the treatment of hematologic malignancies, but not for solid tumors due to adverse side-effects such as immunosuppression and osteoporosis. In tissues, glucocorticoid actions are down-regulated by t y p e 2 1 1 β-hydroxysteroid dehydrogenase (11βHSD2), and inhibition of 11βHSD2 activity will elevate intracellular active glucocorticoid to levels that effectively suppress COX-2 expression. Both COX-2 and 11βHSD2 increase in Apc^+/min mouse intestinal adenomas and human colonic adenomas and either pharmacologic or genetic 11βHSD2 inhibition leads to decreases in COX-2-mediated PGE₂ production in tumors and prevents adenoma formation, tumor growth, and metastasis. 11βHSD2 inhibition may represent a novel approach for CRC chemoprevention by increasing tumor cell intracellular glucocorticoid activity, which in turn inhibits tumor growth by suppressing the COX-2-derived PGE₂ pathway, as well as other pathways, without potential side-effects relating to chronic application of COX-2 inhibitors, NSAIDs and glucocorticoids.

Identification of nuclear protein targets for six leukemogenic tyrosine kinases governed by post-translational regulation

Mutated tyrosine kinases are associated with a number of different haematological malignancies including myeloproliferative disorders, lymphoma and acute myeloid leukaemia. The potential commonalities in the action of six of these leukemogenic proteins on nuclear proteins were investigated using systematic proteomic analysis. The effects on over 3600 nuclear proteins and 1500 phosphopeptide sites were relatively quantified in seven isogenic cell lines. The effects of the kinases were diverse although some commonalities were found. Comparison of the nuclear proteomic data with transcriptome data and cytoplasmic proteomic data indicated that the major changes are due to post-translational mechanisms rather than changes in mRNA or protein distribution. Analysis of the promoter regions of genes whose protein levels changed in response to the kinases showed the most common binding site found was that for NFκB whilst other sites such as those for the glucocorticoid receptor were also found. Glucocorticoid receptor levels and phosphorylation were decreased by all 6 PTKs. Whilst Glucocorticoid receptor action can potentiate NFκB action those proteins where genes have NFκB binding sites were in often regulated post-translationally. However all 6 PTKs showed evidence of NFkB pathway modulation via activation via altered IkB and NFKB levels. Validation of a common change was also undertaken with PMS2, a DNA mismatch repair protein. PMS2 nuclear levels were decreased in response to the expression of all 6 kinases, with no concomitant change in mRNA level or cytosolic protein level. Response to thioguanine, that requires the mismatch repair pathway, was modulated by all 6 oncogenic kinases. In summary common targets for 6 oncogenic PTKs have been found that are regulated by post-translational mechanisms. They represent potential new avenues for therapies but also demonstrate the post-translational regulation is a key target of leukaemogenic kinases.

Correlation between Antistress and Hepatoprotective Effects of Schisandra Lignans Was Related with Its Antioxidative Actions in Liver Cells

The present study was conducted to investigate the relationship between the anti-stress and hepato-protective effects of Schisandra Lignans Extract (SLE) on stress-induced liver damage. Seven weeks old male mice were fixed in a restraint tube for 18 h to induce liver damage. SLE was orally administered to animals for 5 days at dosages of 100 and 200 mg/kg/day before exposed to restraint stress. Oral administration of SLE significantly reduced restraint-induced liver damage in experimental animal. SLE was further found to significantly alleviate the provocation of corticosterone in stressed mice. SLE also significantly decreased oxidative damage and increased anti-oxidative capability of liver cells by preventing the over production and accumulation of free radicals. In conclusion, the protective effects of SLE on stress-induced liver damage were confirmed, and the correlation between hepatoprotective and anti-stress effects of schisandra lignans was possible related to its alleviation on the malignant effects of stressors for bio-homeostasis, such as balance of oxidation and reduction in cells.

Glucocorticoid and proteasome inhibitor impact on the leukemic lymphoblast: multiple, diverse signals converging on a few key downstream regulators

Twenty years ago a proteasome inhibitor was suggested as therapy for glucocorticoid-resistant multiple myeloma, a disease that involves terminally differentiated B cells. Since then, research has proven that it has utility on a number of tumors resistant to chemotherapy. Hematologic malignancy, however, often involves lesser differentiated cells, which have a high potential to modulate their intrinsic machinery and thereby activate alternative rescue pathways. A corresponding multiplicity of therapies is not always practical. One approach to conditions with heterogeneous physiology is to identify key biochemical mediators, thereby reducing the number of treatment targets. Results from several ongoing studies indicate convergence of genomically diverse signal pathways to a limited number of key downstream regulators of apoptosis. Convergence of pathways can be exploited to address the problem of genetic heterogeneity in acute leukemia: this would mean treating multiple molecular aberrations with fewer drugs and enhanced therapeutic benefit.

Involvement of thioredoxin-interacting protein (TXNIP) in glucocorticoid-mediated beta cell death

AIM/HYPOTHESIS

Glucocorticoid hormones (GCs) are widely used to treat a variety of inflammatory and immune diseases. However, their long-term administration is associated with adverse metabolic effects, including glucose intolerance and diabetes. Our objective was to elucidate the mechanisms by which GCs affect beta cell survival with a specific emphasis on the role of the thioredoxin-interacting protein (TXNIP) in beta cell apoptosis.

METHODS

Human and mouse islets, together with MIN6 beta cells, were exposed to dexamethasone (Dex) and apoptosis was assessed by measuring the percentage of sub-G1 cells, the appearance of cleaved caspase-3 or by using a TUNEL assay. Dex-upregulated expression of Txnip mRNA was analysed by real-time PCR, and GC-modulated production and modification of proteins were determined by western blotting.

RESULTS

We provide evidence that TXNIP, a negative regulator of the antioxidant thioredoxin (TRX), is strongly induced in beta cells by GCs and that its induction is dependent on p38 mitogen-activated protein kinase (MAPK) activation. TXNIP downregulation by RNA interference, overexpression of the radical scavenger TRX1 or elevation of intracellular cAMP levels attenuated the Dex-mediated apoptosis. Dex-induced Txnip expression and beta cell apoptosis are mediated by the glucocorticoid receptor (GR), as the GR antagonist RU486 fully abolishes these effects.

CONCLUSIONS/INTERPRETATION

Altogether, our data suggest TXNIP as a novel mediator of GC-induced apoptosis in beta cells and further contribute to our understanding of beta cell death pathways.

Overexpression of P-glycoprotein, STAT3, phospho-STAT3 and KIT in spontaneous canine cutaneous mast cell tumours before and after prednisolone treatment

Prednisolone is a glucocorticoid (GC) commonly used in the treatment of canine mast cell tumours (MCTs); however, resistance to GCs develops in many MCTs following repeated treatment. P-glycoprotein (P-gp), signal transducer and activator of transcription 3 (STAT3) and KIT (CD117) are involved in GC resistance. The aim of this study was to evaluate the response to prednisolone treatment in canine cutaneous MCTs and to investigate the levels of P-gp, STAT3, phospho-STAT3 (pSTAT3) and KIT proteins in MCTs with or without prednisolone treatment. Immunohistochemistry was performed on tumour samples from 41 dogs with cutaneous MCTs. The overall objective response rate (including complete and partial responses) was 51.8% for dogs treated with prednisolone; poorly differentiated or higher stage MCTs had a lower response rate. The median time-span of tumours to reach maximal tumour regression was 14 d (range 3-77 d); 22 (81.5%) reached maximal regression at 21 d. The majority of MCTs overexpressed both P-gp and STAT3 before and after prednisolone treatment. Reduced expression of pSTAT3 and alterations in the KIT expression pattern were observed in MCTs post-treatment. Prednisolone treatment that caused a marked reduction in tumour volume was correlated with reduced pSTAT3 expression. A cytoplasmic KIT staining pattern was correlated with a lower tumour response rate to prednisolone treatment.

O-GlcNAc transferase is involved in glucocorticoid receptor-mediated transrepression

Recruitment of O-GlcNAc transferase (OGT) to promoters plays an important role in gene repression. Glucocorticoid signaling represses the transcriptional activities of NF-κB and AP-1 through direct binding, yet the molecular mechanisms remain to be elucidated. Here we report that OGT is an important component of GR-mediated transrepression. OGT associates with ligand-bound GR in a multi-protein repression complex. Overexpression of OGT potentiates the GR transrepression pathway, whereas depletion of endogenous OGT by RNA interference abolishes the repression. The recruitment of OGT by GR leads to increased O-GlcNAcylation and decreased phosphorylation of RNA polymerase II on target genes. Functionally, overexpression of OGT enhances glucocorticoid-induced apoptosis in resistant cell lines while knockdown of OGT prevents sensitive cell lines from apoptosis. These studies identify a molecular mechanism of GR transrepression, and highlight the function of O-GlcNAc in hormone signaling.