Corticosteroid co-treatment induces resistance to chemotherapy in surgical resections, xenografts and established cell lines of pancreatic cancer

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Overexpression of glucocorticoid receptor promotes the poor progression and induces cisplatin resistance through p38 MAP kinase in cervical cancer patients

Glucocorticoid receptor (GR) is activated by synthetic glucocorticoid or endogenous cortisol which were released by the physical and psychosocial stress, and recent studies reported that it is involved in tumor initiation and metastasis in various solid cancers. However, role of GR in cervical cancer has not been elucidated yet. Therefore, here we aim to unveil the role of GR in cervical cancer with cervical cancer clinical specimen and cervical cancer cell lines. We found that overexpression of GR was associated with poor prognosis in cervical cancer patients. Also, GR knockdown in cervical cancer cell lines showed diminished proliferation, invasion and EMT properties. Besides, we found that GR was positively associated with FoxP3 expression, and combination of GR and FoxP3 overexpression revealed as more reliable biomarker for poor prognosis and poor response to chemotherapy of cervical cancer patient than GR alone. Moreover, FACS-based Annexin-V/PI double staining and cleavage of poly ADP ribose polymerase (PARP) showed that siGR enhanced cisplatin-induced apoptosis, which was mediated by p38 MAP kinase. Collectively, our findings established that the combination of high GR and FoxP3 was associated with cervical cancer progression and platinum resistance, suggesting a potential predictive biomarker for clinical management in patients with cervical cancer.

Advantages and drawbacks of dexamethasone in glioblastoma multiforme

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

Computational insight of dexamethasone against potential targets of SARS-CoV-2

The health sector has been on the race to find a potent therapy for coronavirus disease (COVID)-19, a diseases caused by severe acute respiratory syndrome coronavirus (SARS-CoV)-2. Repurposed anti-viral drugs have played a huge role in combating the virus, and most recently, dexamethasone (Dex) have shown its therapeutic activity in severe cases of COVID-19 patients. The study sought to provide insights on the anti-COVID-19 mechanism of Dex at both atomic and molecular level against SARS-CoV-2 targets. Computational methods were employed to predict the binding affinity of Dex to SARS-CoV-2 using the Schrodinger suite (v2020-2). The target molecules and ligand (Dex) were retrieved from PDB and PubChem, respectively. The selected targets were SARS-CoV-2 main protease (Mpro), and host secreted molecules glucocorticoid receptor, and Interleukin-6 (IL-6). Critical analyses such as Protein and ligand preparation, molecular docking, molecular dynamic (MD) simulations, and absorption, distribution, metabolism, excretion (ADME), and toxicity analyses were performed using the targets and the ligand as inputs. Dex showed stronger affinity to its theoretical (glucocorticoid) receptor with a superior docking score of -14.7 and a good binding energy value of -147.48 kcal/mol; while short hydrogen bond distances were observed in both Mpro and IL-6 when compared to glucocorticoid receptor. Based on these findings, Dex-target complexes were used to perform MD simulations to analyze Dex stability at 50 ns. This study demonstrates that Dex could bind to both the viral and host receptors as a potential drug candidate for COVID-19. To ascertain the biological fitness of this study, other SARS-CoV-2 targets should be explored. Also, the in vitro studies of dexamethasone against several SARS-CoV-2 targets warrant further investigation.Communicated by Ramaswamy H. Sarma.

Outcomes of peri-operative glucocorticosteroid use in major pancreatic resections: a systematic review

BACKGROUND

There is increasing evidence that peri-operative glucocorticosteroid can ameliorate the systemic response following major surgery. Preliminary evidence suggests peri-operative usage of glucocorticosteroid may decrease post-operative complications. These positive associations have been observed in a range of different operations including intra-abdominal, thoracic, cardiac, and orthopaedic surgery. This review aims to investigate the impact of peri-operative glucocorticosteroid in major pancreatic resections.

METHODS

A systematic review based on a search in Medline and Embase databases was performed. PRISMA guidelines for systematic reviews were followed.

RESULTS

A total of five studies were analysed; three randomised controlled trials and two retrospective cohort studies. The total patient population was 1042. The glucocorticosteroids used were intravenous hydrocortisone or dexamethasone. Three studies reported significantly lower morbidity in the peri-operative glucocorticosteroid group. The number needed to treat to prevent one major complication with hydrocortisone is four patients. Two studies demonstrated that dexamethasone was associated with a statistically significantly improved median overall survival in pancreatic cancer.

CONCLUSION

This is the first systematic review conducted to investigate the significance of peri-operative glucocorticosteroid in patients undergoing pancreatic resection. This review shows a correlation of positive outcomes with the administration of glucocorticosteroid in the peri-operative setting following a major pancreatic resection.. More randomised clinical trials are required to confirm if this is a true effect, as it would have significant implications.

Glucocorticoid receptor antagonism promotes apoptosis in solid tumor cells

Background: Resistance to antiproliferative chemotherapies remains a significant challenge in the care of patients with solid tumors. Glucocorticoids, including endogenous cortisol, have been shown to induce pro-survival pathways in epithelial tumor cells. While pro-apoptotic effects of glucocorticoid receptor (GR) antagonism have been demonstrated under select conditions, the breadth and nature of these effects have not been fully established.

Materials and Methods: To guide studies in cancer patients, relacorilant, an investigational selective GR modulator (SGRM) that antagonizes cortisol activity, was assessed in various tumor types, with multiple cytotoxic combination partners, and in the presence of physiological cortisol concentrations.

Results: In the MIA PaCa-2 cell line, paclitaxel-driven apoptosis was blunted by cortisol and restored by relacorilant. In the OVCAR5 cell line, relacorilant improved the efficacy of paclitaxel and the potency of platinum agents. A screen to identify optimal combination partners for relacorilant showed that microtubule-targeted agents consistently benefited from combination with relacorilant. These findings were confirmed in xenograft models, including MIA PaCa-2, HeLa, and a cholangiocarcinoma patient-derived xenograft. In vivo, tumor-cell apoptosis was increased when relacorilant was added to paclitaxel in multiple models.

Conclusions: These observations support recently reported findings of clinical benefit when relacorilant is added to paclitaxel-containing therapy in patients with ovarian and pancreatic cancers and provide a new rationale for combining relacorilant with additional cytotoxic agents.

Self-Assembling Derivative of Hydrocortisone as Glucocorticoid Receptor-Targeted Nanotherapeutics for Synergistic, Combination Therapy against Colorectal Tumor

Hydrocortisone, a natural glucocorticoid secreted by adrenal and extra-adrenal tissues, locally governs the transcription of genes involved in inflammation, immune response, metabolism, and energy homeostasis via binding to its cognate glucocorticoid receptor (GR). In this study, we show that modified hydrocortisone (HC16), a cancer-selective cytotoxic molecule, showed synergism in combination with drugs like Doxorubicin and docetaxel, self-assembled into vesicles, entrapped docetaxel and complexed with anti-cancer plasmid DNA for enhanced killing of cancer cells. These vesicles exhibited GR-mediated nuclear localization, delivery of the p53 gene, and also inhibited cell viability selectively in RKO, HCT15, and CT26 colon cancer cells but not in normal cells like CHO and HEK293T. Apart from exerting its own anti-cancer activity, the self-assembled HC16 vesicles loaded with docetaxel sensitized the cancer cells to its drug cargo by downregulating the drug metabolizing CYP3A4 gene. This indirectly reduces the risk of nonspecific adverse effects in normal cells, as the viability of sensitized cancer cells could be significantly reduced even in low doses of cytotoxic docetaxel. The near infrared (NIR)-dye-associated self-assemblies accumulated in a colon tumor with higher orders of NIR intensity compared to those in a colon of healthy mice. Thereafter, the treatment of HC16-docetaxel-p53 vesicle/DNA complex led to significant tumor regression, which resulted in a cecum/body weight ratio in tumor-bearing mice similar to that of healthy mice measured at 24 h postcompletion of treatment. There was an up to 2.5-fold enhancement in the overall survivability of colon-tumor-bearing mice treated with HC16-docetaxel-p53 vesicle/DNA complexes when compared against the pristine docetaxel-treated groups. Further, the HC16-docetaxel-p53 vesicle/DNA complex-treated group showed reduced nuclear accumulation of cell proliferation marker Ki67, reduced protein levels of prosurvival and mesenchymal proteins like Bcl-2, PARP, vimentin, and N-cadherin, and increased the levels of pro-apoptotic activated caspases as compared to the pristine docetaxel-treated groups. The therapeutic package described herein is expected to find future use as a rational, multifaceted, GR-targeted approach for inhibiting colon tumor progression.

Stress and drug resistance in cancer

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

Glucocorticoid receptor expression is associated with inferior overall survival independent of BRCA mutation status in ovarian cancer

OBJECTIVE

High glucocorticoid receptor (GR) protein expression is associated with decreased progression-free survival in ovarian cancer patients and decreased sensitivity to chemotherapy in preclinical models. Prior studies suggest wild type BRCA1 promotes GR activation. The objective of this study was to characterize the relationship of tumor GR gene expression to outcome in ovarian cancer, and to evaluate the relationship of GR expression with BRCA status.

METHODS

Whole exome and whole genome sequencing, gene expression, and clinical data were obtained for high-grade serous ovarian cancers in The Cancer Genome Atlas. Cases with pathogenic somatic or germline BRCA1 or BRCA2 mutations were identified and classified as BRCA mutated. High or low glucocorticoid receptor expression was defined as expression above or below median of the GR/nuclear receptor subfamily 3 C1 (NR3C1) gene level. Overall survival was estimated by the Kaplan-Meier method and compared by Cox regression analysis.

RESULTS

Combined germline DNA sequencing and tumor microarray expression data were available for 222 high-grade serous ovarian cancer cases. Among these, 47 had a deleterious germline and/or somatic mutation in BRCA1 or BRCA2. In multivariate analysis, high glucocorticoid receptor gene expression was associated with decreased overall survival among ovarian cancer patients, independently of BRCA mutation status. No correlation of GR/NR3C1 gene expression with BRCA mutation status or BRCA1 or BRCA2 mRNA level was observed.

CONCLUSIONS

Increased GR gene expression is associated with decreased overall survival in ovarian cancer patients, independently of BRCA mutation status. High-grade serous ovarian cancers with high GR expression and wild type BRCA have a particularly poor outcome.

Dexamethasone alleviates pemetrexed-induced senescence in Non-Small-Cell Lung Cancer

Pemetrexed (PEM) is a novel and multi-targeted antifolate used as an antineoplastic agent for non-small cell lung cancer (NSCLC) and pleural mesothelioma. Although glucocorticoid was often used with PEM to reduce toxicity during the chemotherapy, it is not clear yet whether glucocorticoid co-administration could affect PEM efficacy in NSCLC. Here we established NSCLC cell lines and examined the effects of dexamethasone (DEX) on PEM sensitivity in vitro and in xenograft models. DEX co-administration reduced chemotherapy sensitivity to PEM in xenograft models. DEX co-administration promoted cell growth and weakened senescence growth arrest, such as altered secretions of proinflammatory and mitogenic cytokines, reminiscent of a senescence associate secretory phenotype (SASP). CSCs in DEX co-administration group were subsequently found to be less sensitive towards PEM treatment as measured by cell proliferation and generation of tumor spheres in the presence of PEM. Survival molecule B-cell lymphoma-2 (Bcl-2) may involve in this process and blockage of Bcl-2 could reverse altered senescence and CSCs abilities, thus alleviated PEM insensitivity. As such, DEX might suppress the antitumor activity of PEM through altered SASP level that had induced traits similar to CSCs.

A dual role for glucocorticoid-induced leucine zipper in glucocorticoid function: tumor growth promotion or suppression?

Glucocorticoids (GCs), important therapeutic tools to treat inflammatory and immunosuppressive diseases, can also be used as part of cancer therapy. In oncology, GCs are used as anticancer drugs for lymphohematopoietic malignancies, while in solid neoplasms primarily to control the side effects of chemo/radiotherapy treatments. The molecular mechanisms underlying the effects of GCs are numerous and often overlapping, but not all have been elucidated. In normal, cancerous, and inflammatory tissues, the response to GCs differs based on the tissue type. The effects of GCs are dependent on several factors: the tumor type, the GC therapy being used, the expression level of the glucocorticoid receptor (GR), and the presence of any other stimuli such as signals from immune cells and the tumor microenvironment. Therefore, GCs may either promote or suppress tumor growth via different molecular mechanisms. Stress exposure results in dysregulation of the hypothalamic-pituitary-adrenal axis with increased levels of endogenous GCs that promote tumorigenesis, confirming the importance of GCs in tumor growth. Most of the effects of GCs are genomic and mediated by the modulation of GR gene transcription. Moreover, among the GR-induced genes, glucocorticoid-induced leucine zipper (GILZ), which was cloned and characterized primarily in our laboratory, mediates many GC anti-inflammatory effects. In this review, we analyzed the possible role for GILZ in the effects GCs have on tumors cells. We also suggest that GILZ, by affecting the immune system, tumor microenvironment, and directly cancer cell biology, has a tumor-promoting function. However, it may also induce apoptosis or decrease the proliferation of cancer cells, thus inhibiting tumor growth. The potential therapeutic implications of GILZ activity on tumor cells are discussed here.

Discovery of a Glucocorticoid Receptor (GR) Activity Signature Using Selective GR Antagonism in ER-Negative Breast Cancer

Purpose: Although high glucocorticoid receptor (GR) expression in early-stage estrogen receptor (ER)-negative breast cancer is associated with shortened relapse-free survival (RFS), how associated GR transcriptional activity contributes to aggressive breast cancer behavior is not well understood. Using potent GR antagonists and primary tumor gene expression data, we sought to identify a tumor-relevant gene signature based on GR activity that would be more predictive than GR expression alone.Experimental Design: Global gene expression and GR ChIP-sequencing were performed to identify GR-regulated genes inhibited by two chemically distinct GR antagonists, mifepristone and CORT108297. Differentially expressed genes from MDA-MB-231 cells were cross-evaluated with significantly expressed genes in GR-high versus GR-low ER-negative primary breast cancers. The resulting subset of GR-targeted genes was analyzed in two independent ER-negative breast cancer cohorts to derive and then validate the GR activity signature (GRsig).Results: Gene expression pathway analysis of glucocorticoid-regulated genes (inhibited by GR antagonism) revealed cell survival and invasion functions. GR ChIP-seq analysis demonstrated that GR antagonists decreased GR chromatin association for a subset of genes. A GRsig that comprised n = 74 GR activation-associated genes (also reversed by GR antagonists) was derived from an adjuvant chemotherapy-treated Discovery cohort and found to predict probability of relapse in a separate Validation cohort (HR = 1.9; P = 0.012).Conclusions: The GRsig discovered herein identifies high-risk ER-negative/GR-positive breast cancers most likely to relapse despite administration of adjuvant chemotherapy. Because GR antagonism can reverse expression of these genes, we propose that addition of a GR antagonist to chemotherapy may improve outcome for these high-risk patients. Clin Cancer Res; 24(14); 3433-46. ©2018 AACR.

Dexamethasone mediates pancreatic cancer progression by glucocorticoid receptor, TGFβ and JNK/AP-1

Glucocorticoids such as dexamethasone are widely co-prescribed with cytotoxic therapy because of their proapoptotic effects in lymphoid cancer, reduction of inflammation and edema and additional benefits. Concerns about glucocorticoid-induced therapy resistance, enhanced metastasis and reduced survival of patients are largely not considered. We analyzed dexamethasone-induced tumor progression in three established and one primary human pancreatic ductal adenocarcinoma (PDA) cell lines and in PDA tissue from patients and xenografts by FACS and western blot analysis, immunohistochemistry, MTT and wound assay, colony and spheroid formation, EMSA and in vivo tumor growth and metastasis of tumor xenografts on chicken eggs and mice. Dexamethasone in concentrations observed in plasma of patients favored epithelial–mesenchymal transition, self-renewal potential and cancer progression. Ras/JNK signaling, enhanced expression of TGFβ, vimentin, Notch-1 and SOX-2 and the inhibition of E-cadherin occurred. This was confirmed in patient and xenograft tissue, where dexamethasone induced tumor proliferation, gemcitabine resistance and metastasis. Inhibition of each TGFβ receptor-I, glucocorticoid receptor or JNK signaling partially reversed the dexamethasone-mediated effects, suggesting a complex signaling network. These data reveal that dexamethasone mediates progression by membrane effects and binding to glucocorticoid receptor.

High glucocorticoid receptor expression predicts short progression-free survival in ovarian cancer

OBJECTIVE

To investigate the association of tumor glucocorticoid receptor (GR) expression and patient outcome in ovarian cancer.

METHODS

GR expression was evaluated by immunohistochemistry using tissue microarrays of specimens from 481 patients with ovarian cancer and 4 patients with benign conditions. Low GR expression was defined as an intensity of 0 or 1+ and high GR as 2+ or 3+ in >1% of tumor cells. Analyses were performed to evaluate the relationship of GR expression with clinical characteristics, progression-free survival (PFS) and overall survival (OS).

RESULTS

GR protein was highly expressed in 133 of 341 (39.0%) tumors from patients who underwent upfront cytoreduction surgery followed by adjuvant chemotherapy. High GR expression was more common in serous tumors (p<0.001), high grade tumors (p<0.001), and advanced stage tumors (p=0.037). Median PFS was significantly decreased in cases with high GR (20.4months) compared to those with low GR (36.0months, HR=1.66, 95% CI 1.29-2.14, p<0.001). GR remained an independent prognostic factor for PFS in multivariate analysis. OS was not associated with GR status.

CONCLUSIONS

These data suggest that high GR expression correlates with poor prognosis and support the hypothesis that modulating GR activity in combination with chemotherapy may improve outcomes.

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.

New dimension of glucocorticoids in cancer treatment

Glucocorticoids have been used in clinical oncology for over half a century. The clinical applications of glucocorticoids in oncology are mainly dependent on their pro-apoptotic action to treat lymphoproliferative disorders, and also on alleviating side effects induced by chemotherapy or radiotherapy in non-hematologic cancer types. Researches in the past few years have begun to unveil the profound complexity of glucocorticoids signaling and have contributed remarkably on therapeutic strategies. However, it remains striking and puzzling how glucocorticoids use different mechanisms in different cancer types and different targets to promote or inhibit tumor progression. In this review, we provide an update on glucocorticoids and its receptor, GR-mediated signaling and highlight some of the latest findings on the actions of glucocorticoids signaling during tumor progression and metastasis.

The effects of dexamethasone on the proliferation and apoptosis of human ovarian cancer cells induced by paclitaxel

BACKGROUND

Dexamethasone (DEX) has been routinely used as a pre-treatment in the clinical application of paclitaxel (PTX) to treat ovarian cancer. However, PTX-induced apoptosis might be inhibited by DEX. This study was undertaken to investigate the effects of DEX on the apoptosis induced by PTX.

METHODS

Both of SKOV-3 and HO-8910 human ovarian cancer cells were divided into four groups: (1) untreated (Con); (2) treated with DEX (0.1 μM) alone; (3) treated with PTX (50 nM); and (4) pre-treated with DEX (0.1 μM), and 24 h later, treated with PTX (DEX + PTX). Cell proliferation was determined by the 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) dye uptake method, while cell apoptosis was analyzed by propidium iodide (PI) staining and flow cytometry. Then, reverse transcription polymerase chain reactions (RT-PCRs) were applied to semi-quantitative analysis, followed by western blot analysis. Statistical analysis was performed, with Fisher's least significant difference test.

RESULTS

Our results demonstrated that DEX can differentially inhibit SKOV-3 and HO-8910 cell proliferation induced by PTX and decrease the apoptosis rates in cancer cells. Pre-treatment with DEX could up-regulate the expressions of members of anti-apoptotic Bcl-2 family (Bcl-2 and Bcl-XL) and members of IAP family (survivin). The expression of cleaved caspase-3 was down-regulated by DEX, shown by semi-quantitative RT-PCRs and western blot analysis.

CONCLUSIONS

Our data gained invaluable insights of the antagonistic mechanisms of DEX on PTX-induced cancer cell death and may provide new methods of using DEX as antineoplastic drugs or agents in the clinical treatment for ovarian cancer patients.

Analysis of gene expression for studying tumor progression: the case of glucocorticoid administration

BACKGROUND

Glucocorticoids are commonly used as adjuvant treatment for side-effects and have anti-proliferative activity in several tumors but, on the other hand, their proliferative effect has been reported in several studies, some of them involving the spread of cancer. We shall attempt to reconcile these incongruities from the genomic and tissue-physiology perspectives with our findings.

METHODS

An accurate phenotype analysis of microarray data can help to solve multiple paradoxes derived from tumor-progression models. We have developed a new strategy to facilitate the study of interdependences among the phenotypes defined by the sample clusters obtained by common clustering methods (HC, SOTA, SOM, PAM). These interdependences are obtained by the detection of non-linear expression-relationships where each fluctuation in the relationship implies a phenotype change and each relationship typology implies a specific phenotype interdependence. As a result, multiple phenotypic changes are identified together with the genes involved in the phenotype transitions. In this way, we study the phenotypic changes from microarray data that describe common phenotypes in cancer from different tissues, and we cross our results with biomedical databases to relate the glucocorticoid activity to the phenotypic changes.

RESULTS

11,244 significant non-linear expression relationships, classified into 11 different typologies, have been detected from the data matrix analyzed. From them, 415 non-linear expression relationships were related to glucocorticoid activity. Studying them, we have found the possible reason for opposite effects of some stressor agents like dexamethasone on tumor progression and it has been confirmed by literature. This hidden reason has resulted in being linked with the type of tumor progression of the tissues. In the first type of tumor progression found, new cells can be stressed during proliferation and stressor agents increase tumor proliferation. In the second type, cell stress and tumor proliferation are antagonists so, therefore, stressor agents stop tumor proliferation in order to stress the cells. The non-linear expression relationships among DUSP6, FERMT2, FKBP5, EGFR, NEDD4L and CITED2 genes are used to synthesize these findings.

High glucose-induced resistance to 5-fluorouracil in pancreatic cancer cells alleviated by 2-deoxy-D-glucose

Abnormal glucose metabolism from hyperglycemia or diabetes aggravates the progression of pancreatic cancer. It is unknown whether high glucose has an impact on the antitumor effect of 5-fluorouracil (5-Fu) and whether targeting aberrant glucose metabolism using 2-deoxy-D-glucose (2-DG) may reverse this effect in high-glucose microenvironments. The cell viability of AsPC-1 and Panc-1 was analyzed by MTT assay following 5-Fu treatment at different glucose concentrations. Altered sensitivity to 5-Fu by 2-DG was also analyzed. LY294002 was used to inhibit PI3K-Akt signaling to determine the mechanism involved. In response to glucose, 5-Fu-induced cell growth inhibition was attenuated in a dose-dependent manner, accompanied with activated p-Akt, while 2-DG enhanced 5-Fu-induced cell growth inhibition. Moreover, blocking the PI3K/Akt pathway by LY294002 effectively eliminated 2-DG-induced apoptosis. In conclusion, high glucose weakens the antitumor effect of 5-Fu via PI3K/Akt signaling. Using 2-DG in combination with 5-Fu significantly increased their therapeutic effectiveness in high-glucose microenvironments.

Identification and bioinformatic analysis of differentially expressed genes in pancreatic cancer stem cells

AIM: To identify differentially expressed genes in pancreatic cancer stem cells and to analyze them by bioinformatics.

METHODS: MIA-PaCa2 (TIC^high) and BxPc-3 (TIC^low) were used as tool cells in this study. Total RNA was prepared from MIA-PaCa2 (TIC^high) and BxPc-3 (TIC^low) cells. After quality identification and fluorescent labeling, RNA samples were hybridized with the Agilent human gene expression microarrays. Raw data were normalized using Quantile algorithm and Gene Spring Software 11.0. Gene Ontology database and KEGG database were used for GO and Pathway comments on differentially expressed genes, respectively.

RESULTS: A total of 7059 differentially expressed genes were identified (P < 0.05, fold change ≥ 2), including 3440 up-regulated and 3619 down-regulated genes in MIA-PaCa2 (TIC^high) cells. These differentially expressed genes were mainly involved in polyamine metabolic process, nucleobase-containing small molecule interconversion, histone H4 acetylation, cell division, cell cycle, apoptotic process, and toll-like receptor signaling pathway. GO analysis demonstrated they are involved in cancer, endocytosis, O-glycan biosynthesis, pyrimidine metabolism, and glutathione metabolism. Pathway analysis showed the presence of crosstalk among several signaling pathways.

CONCLUSION: Differentially expressed genes identified in this study may be involved in the regulation of different signaling pathways and the genesis of pancreatic cancer stem cells. They might become new therapeutic targets for pancreatic cancer.

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.

Quantitative proteomic analysis of differentially expressed proteins in pancreatic cancer stem cells

AIM: To screen and identify differentially expressed proteins in pancreatic cancer stem cells.

METHODS: MIA-PaCa2 (TIC^high) and BxPc-3 (TIC^low) were used in the study. Differentially expressed proteins between MIA-PaCa2 (TIC^high) and BxPc-3 (TI^Clow) cells were isolated and screened by 2D-DIGE analysis. Protein identification was performed by peptide mass fingerprinting with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF). Western blot was performed to verify the differential expression of TRIM28.

RESULTS: Fluorescent differential protein expression patterns were obtained between MIA-PaCa2 (TIC^high) and BxPc-3 (TIC^low) cells. Analyses with DeCyder v6.5 software showed a total of 23 differentially expressed protein spots (>1.5 folds), and these protein spots were identified by mass spectrometry as 19 proteins, which are involved in cell communication and signal transduction, immune response, transcription and cell cycle regulation, adipocyte differentiation and lipid droplet formation, cytoskeletal formation, cell adhesion, transport, and translation. Western blot analysis revealed that TRIM28 was highly expressed in MIA-PaCa2 (TIC^high) cells but not expressed in BxPc-3 (TIC^low) cells. Among the 19 identified proteins, 8 were up-regulated and 11 down-regulated in MIA-PaCa2 (TIC^high) cells.

CONCLUSION: The identified differentially expressed proteins, such as TRIM28, are associated with the genesis, development and regulation of pancreatic cancer stem cells. They may become new therapeutic targets for pancreatic cancer.

Dexamethasone reduces sensitivity to cisplatin by blunting p53-dependent cellular senescence in non-small cell lung cancer

Introduction

Dexamethasone (DEX) co-treatment has proved beneficial in NSCLC patients, improving clinical symptoms by the reduction of side effects after chemotherapy. However, recent studies have shown that DEX could render cancer cells more insensitive to cytotoxic drug therapy, but it is not known whether DEX co-treatment could influence therapy-induced senescence (TIS), and unknown whether it is in a p53-dependent or p53-independent manner.

Methods

We examined in different human NSCLC cell lines and detected cellular senescence after cisplatin (DDP) treatment in the presence or absence of DEX. The in vivo effect of the combination of DEX and DDP was assessed by tumor growth experiments using human lung cancer cell lines growing as xenograft tumors in nude mice.

Results

Co-treatment with DEX during chemotherapy in NSCLC resulted in increased tumor cell viability and inhibition of TIS compared with DDP treated group. DEX co-treatment cells exhibited the decrease of DNA damage signaling pathway proteins, the lower expression of p53 and p21^CIP1, the lower cellular secretory program and down-regulation of NF-κB and its signaling cascade. DEX also significantly reduced DDP sensitivity in vivo.

Conclusions

Our results underscore that DEX reduces chemotherapy sensitivity by blunting therapy induced cellular senescence after chemotherapy in NSCLC, which may, at least in part, in a p53-dependent manner. These data therefore raise concerns about the widespread combined use of gluocorticoids (GCs) with antineoplastic drugs in the clinical management of cancer patients.

Identification of differentially expressed microRNAs in pancreatic cancer stem cells

AIM: To screen and identify differentially expressed miRNAs in pancreatic cancer stem cells and to analyze them by bioinformatics.

METHODS: Total RNA was prepared from MIA-PaCa2 (TIC^high) and BxPc-3 (TIC^low) cells. After quality identification and fluorescent labeling, the RNA samples were hybridized with Agilent human miRNA microarrays. Raw data were normalized using Quantile algorithm and Gene Spring Software 11.0. Part of differentially expressed miRNAs were validated by SYBR Green real-time PCR. Sanger database was used to predict target genes for differentially expressed miRNAs. Gene Ontology database and KEGG database were used for GO annotations and Pathway annotations of target genes, respectively.

RESULTS: A total of 940 miRNAs were identified and among them 91 were differentially expressed (P < 0.05, fold change ≥ 2), including 45 up-regulated and 46 down-regulated ones in MIA-PaCa2 (TIC^high). Twenty-one miRNAs were validated by real-time PCR, and the results for 19 miRNAs were consistent with those of chip detection. 2 895 target genes were predicted for 91 differentially expressed miRNAs, and these genes were mainly involved in events, such as axon guidance, angiogenesis, and post-translational protein modification, and in pathways such as cancer, focal adhesion, Hedgehog signaling pathway, and MAPK signaling pathway.

CONCLUSION: Many differentially expressed miRNAs in pancreatic cancer stem cells have been identified, and their target genes are involved in a variety of biological events and in multiple signal pathways. These differentially expressed miRNAs may become new therapeutic targets for pancreatic cancer.

Glucocorticoid compounds modify smoothened localization and hedgehog pathway activity

The Hedgehog signaling pathway is linked to a variety of diseases, notably a range of cancers. The first generation of drug screens identified Smoothened (Smo), a membrane protein essential for signaling, as an attractive drug target. Smo localizes to the primary cilium upon pathway activation, and this transition is critical for the response to Hedgehog ligands. In a high content screen directly monitoring Smo distribution in Hedgehog-responsive cells, we identified different glucocorticoids as specific modulators of Smo ciliary accumulation. One class promoted Smo accumulation, conferring cellular hypersensitivity to Hedgehog stimulation. In contrast, a second class inhibited Smo ciliary localization and signaling activity by both wild-type Smo, and mutant forms of Smo, SmoM2, and SmoD473H, that are refractory to previously identified Smo antagonists. These findings point to the potential for developing glucocorticoid-based pharmacological modulation of Smo signaling to treat mutated drug-resistant forms of Smo, an emerging problem in long-term cancer therapy. They also raise a concern about potential crosstalk of glucocorticoid drugs in the Hedgehog pathway, if therapeutic administration exceeds levels associated with on-target transcriptional mechanisms of glucocorticoid action.

Chronic restraint stress attenuates p53 function and promotes tumorigenesis

Epidemiological studies strongly suggest that chronic psychological stress promotes tumorigenesis. However, its direct link in vivo and the underlying mechanisms that cause this remain unclear. This study provides direct evidence that chronic stress promotes tumorigenesis in vivo; chronic restraint, a well-established mouse model to induce chronic stress, greatly promotes ionizing radiation (IR)-induced tumorigenesis in p53(+/-) mice. The tumor suppressor protein p53 plays a central role in tumor prevention. Loss or attenuation of p53 function contriubutes greatly to tumorigenesis. We found that chronic restraint decreases the levels and function of p53 in mice, and furthermore, promotes the growth of human xenograft tumors in a largely p53-dependent manner. Our results show that glucocorticoids elevated during chronic restraint mediate the effect of chronic restraint on p53 through the induction of serum- and glucocorticoid-induced protein kinase (SGK1), which in turn increases MDM2 activity and decreases p53 function. Taken together, this study demonstrates that chronic stress promotes tumorigenesis in mice, and the attenuation of p53 function is an important part of the underlying mechanism, which can be mediated by glucocortcoids elevated during chronic restraint.

Targeting of cancer stem cell marker EpCAM by bispecific antibody EpCAMxCD3 inhibits pancreatic carcinoma

Patients with pancreatic cancer have a poor survival rate, and new therapeutic strategies are needed. Epithelial cell adhesion molecule (EpCAM), suggested as a marker for cancer stem cells, is over-expressed on most pancreatic tumour cells but not on normal cells and may be an ideal therapeutic target. We evaluated the anti-tumour efficiency of bispecific EpCAMxCD3 antibody linking tumour cells and T lymphocytes. In NOD SCID mice, EpCAMxCD3 had a long serum half-life (t_1/2∼ 7 days). EpCAMxCD3 significantly retarded growth of BxPC-3 pancreatic carcinoma xenografts. For mimicking a pancreatic cancer microenvironment in vitro, we used a three-dimensional tumour reconstruct system, in which lymphocytes were co-cultured with tumour cells and fibroblasts in a collagen matrix. In this in vivo–like system, EpCAMxCD3 potently stimulated production of the effector cytokines IFN-γ and TNF-α by extracorporally pre-activated lymphocytes. Moreover, compared with a bivalent anti-CD3 antibody, EpCAMxCD3 more efficiently activated the production of TNF-α and IFN-γ by non-stimulated peripheral blood mononuclear cells. Most excitingly, we demonstrate for the first time that EpCAMxCD3 induces prolonged contacts between lymphocytes and tumour cells, which may be the main reason for the observed anti-tumour effects. As an important prerequisite for future use in patients, EpCAMxCD3 did not alter lymphocyte migration as measured by time-lapse video microscopy. Our data may open a way to improve the immune response and treatment outcome in patients with pancreatic cancer.

Impact of stress on cancer metastasis

The influence of psychosocial factors on the development and progression of cancer has been a longstanding hypothesis since ancient times. In fact, epidemiological and clinical studies over the past 30 years have provided strong evidence for links between chronic stress, depression and social isolation and cancer progression. By contrast, there is only limited evidence for the role of these behavioral factors in cancer initiation. Recent cellular and molecular studies have identified specific signaling pathways that impact cancer growth and metastasis. This article provides an overview of the relationship between psychosocial factors, specifically chronic stress, and cancer progression.

Computerized detection and analysis of cancer chemotherapy-induced emesis in a small animal model, musk shrew

Vomiting is a common side effect of cancer chemotherapy and many drug treatments and diseases. In animal studies, the measurement of vomiting usually requires direct observation, which is time consuming and often lacks temporal precision. Musk shrews have been used to study the neurobiology of emesis and have a rapid emetic episode (∼1 s for a sequence of retching and expulsion). The aim of the current study was to develop a method to automatically detect and characterize emetic episodes induced by the cancer chemotherapy agent cisplatin. The body contour in each video frame was tracked and normalized to a parameterized shape basis. The tracked shape was projected to a feature space that maximized the shape variations in the consecutive frames during retching. The resulting one dimensional projection was sufficient to detect most emetic episodes in the acute (peak at 2h) and delayed (peak at 54 h) phases after cisplatin treatment. Emetic episodes were relatively invariant in the number of retches (∼6.2), duration (∼1.2s), inter-retch interval (∼198 ms), and amplitude during the 72 h after cisplatin treatment. This approach should open a new vista into emesis research to permit tracking and analysis of emesis in a small animal model and facilitate the development of new antiemetic therapies. These results also yield a better understanding of the brain's central pattern generator for emesis and indicate that the retching response in the musk shrew (at ∼5.4 Hz) is the fastest ever recorded in a free-moving animal.

Synergistic activity of sorafenib and sulforaphane abolishes pancreatic cancer stem cell characteristics

Recent evidence suggests that pancreatic cancer and other solid tumors contain a subset of tumorigenic cells capable of extensive self-renewal that contribute to metastasis and treatment resistance. Sorafenib (SO) is a promising new multikinase inhibitor for treatment of advanced kidney and liver cancers. We report here targeting of pancreatic cancer stem cells (CSC) by SO and the development of a strategy to enhance this effect. Although SO administration diminished clonogenicity, spheroid formation, aldehyde dehydrogenase 1 (ALDH1) activity, growth on immunodeficient mice, proliferation, and angiogenesis and induced apoptosis, we observed SO-induced activation of NF-kappaB associated with survival and regrowth of spheroids. For enhanced elimination of CSC characteristics by SO, we cotreated cells with sulforaphane (SF). This broccoli isothiocyanate was recently described to eliminate pancreatic CSCs by downregulation of NF-kappaB activity without inducing toxic side effects. On combination treatment, SF completely eradicated SO-induced NF-kappaB binding, which was associated with abrogated clonogenicity, spheroid formation, ALDH1 activity, migratory capacity, and induction of apoptosis. In vivo, combination therapy reduced the tumor size in a synergistic manner. This was due to induction of apoptosis, inhibition of proliferation and angiogenesis, and downregulation of SO-induced expression of proteins involved in epithelial-mesenchymal transition. Our data suggest that SF may be suited to increase targeting of CSCs by SO.

Overexpression of glucocorticoid receptor in human pancreatic cancer and in xenografts. An immunohistochemical study

Glucocorticoid receptor overexpression has been reported in a variety of human solid tumors, but much less in known about its presence in pancreatic cancer. Only one report is available in the literature, back to 1994, since that no peculiar attention has been paid to this issue. Immunohistochemical analysis of paraffin-embedded tissue sections was performed in human normal pancreata and well differentiated pancreatic adenocarcinomas (monoclonal primary antibody, ABCAM, Cambridge, UK). As positive control invasive ductal adenocarcinoma of the breast was used. In the normal non-tumorous pancreas a strong positivity was detected in all acinar cells, typically in the cytoplasm. Nuclear staining was not visible. The distribution of the positive reaction was homogenous. The ductal pancreatic carcinoma cells also displayed a strong positivity. The location of the immune reaction was mainly cytoplasmic but in some tumors a strong nuclear reaction was also noticed. In some slides acini remained also positive in the close vicinity of the tumor. Although the positivity of the ductal tumor cells was a constant finding in our samples, surprisingly, the liver metastasis was completely negative. Strong glucocorticoid receptor expression was also found in xenografted human pancreatic cancer showing a diffuse, mainly cytoplasmic positivity. Our studies have shown that the human pancreatic carcinomas do overexpress a strong glucocorticoid receptor positivity, but its significance is not clear. However, this finding might have a clinical relevance.

Mechanisms regulating the susceptibility of hematopoietic malignancies to glucocorticoid-induced apoptosis

Glucocorticoids (GCs) are commonly used in the treatment of hematopoietic malignancies owing to their ability to induce apoptosis of these cancerous cells. Whereas some types of lymphoma and leukemia respond well to this drug, others are resistant. Also, GC-resistance gradually develops upon repeated treatments ultimately leading to refractory relapsed disease. Understanding the mechanisms regulating GC-induced apoptosis is therefore uttermost important for designing novel treatment strategies that overcome GC-resistance. This review discusses updated data describing the complex regulation of the cell's susceptibility to apoptosis triggered by GCs. We address both the genomic and nongenomic effects involved in promoting the apoptotic signals as well as the resistance mechanisms opposing these signals. Eventually we address potential strategies of clinical relevance that sensitize GC-resistant lymphoma and leukemia cells to this drug. The major target is the nongenomic signal transduction machinery where the interplay between protein kinases determines the cell fate. Shifting the balance of the kinome towards a state where Glycogen synthase kinase 3alpha (GSK3alpha) is kept active, favors an apoptotic response. Accumulating data show that it is possible to therapeutically modulate GC-resistance in patients, thereby improving the response to GC therapy.

Glucocorticoid-mediated apoptosis resistance of solid tumors

More than a quarter of a century ago, the phenomenon of glucocorticoid-induced apoptosis in the majority of hematological cells was first recognized. More recently, glucocorticoid-induced antiapoptotic signaling associated with apoptosis resistance towards cytotoxic therapy has been identified in cells of epithelial origin, most of malignant solid tumors and some other tissues. Despite these huge amounts of data demonstrating differential pro- and anti-apoptotic effects of glucocorticoids, the underlying mechanisms of cell type-specific glucocorticoid signaling are just beginning to be described. This review summarizes our present understanding of cell type-specific pro- and anti-apoptotic signaling induced by glucocorticoids. We shortly introduce mechanisms of glucocorticoid resistance of hematological cells. We highlight and discuss the emerging molecular evidence of a general induction of survival signaling in epithelial cells and carcinoma cells by glucocorticoids. We give a summary of our current knowledge of decreased proliferation rates in response to glucocorticoid pre- and combination treatment, which are suspicious to be involved not only in protection of normal tissues, but also in protection of solid tumors from cytotoxic effects of anticancer agents.

Regulation of differential pro- and anti-apoptotic signaling by glucocorticoids

More than a quarter of a century ago, the phenomenon of glucocorticoid-induced apoptosis in the majority of hematological cells was first recognized. More recently, glucocorticoid-induced antiapoptotic signaling associated with apoptosis resistance has been identified in cells of epithelial origin, most of malignant solid tumors and some other tissues. Despite these huge amount of data demonstrating differential pro- and anti-apoptotic effects of glucocorticoids, the underlying mechanisms of cell type specific glucocorticoid signaling are just beginning to be described. This review summarizes our present understanding of cell type-specific pro- and anti-apoptotic signaling induced by glucocorticoids. In the first section we give a summary and update of known glucocorticoid-induced pathways mediating apoptosis in hematological cells. We shortly introduce mechanisms of glucocorticoid resistance of hematological cells. We highlight and discuss the emerging molecular evidence of a general induction of survival signaling in epithelial cells and carcinoma cells by glucocorticoids. We provide a model for glucocorticoid-induced resistance in cells growing in a tissue formation. Thus, attachment to the extracellular matrix and cell-cell contacts typical for e.g. epithelial and tumor cells may be crucially involved in switching the balance of several interacting pathways to survival upon treatment with glucocorticoids.

Glucocorticoid use in prostate cancer and other solid tumours: implications for effectiveness of cytotoxic treatment and metastases

Glucocorticoids have been used widely in conjunction with other treatment for patients with cancer because they have potent proapoptotic properties in lymphoid cells, can reduce nausea, and alleviate acute toxic effects in healthy tissue. However, glucocorticoids are used in a supportive-care role, even though to our knowledge no prospective clinical studies have assessed the effect of these steroids on the growth of solid tumours. Data from preclinical and, to some extent, clinical studies, suggest that glucocorticoids induce treatment resistance in solid tumours, including prostate cancer. Research has focussed on disseminated cells that have been shed by the tumour: the potential of glucocorticoids to render these cells resistant to apoptosis--and to downregulate the immune response--might contribute to tumour metastasis. Here, we review the benefits of glucocorticoids and their negative effects, such as induction of resistance in tumour cells and concomitant induction of apoptosis in immune cells, with particular emphasis on prostate cancer.