Differential Expression of Glucocorticoid Receptor Noncoding RNA Repressor Gas5 in Autoimmune and Inflammatory Diseases.

Glucocorticoids have strong regulatory actions on the immune system and act as potent therapeutic compounds for autoimmune and inflammatory diseases. We previously reported that the long noncoding RNA growth arrest-specific 5 (Gas5), which accumulates inside the cells in response to cellular starvation/growth arrest, functions as a potent repressor of the glucocorticoid receptor (GR) through its RNA "glucocorticoid response element (GRE)". To evaluate potential roles of Gas5 in immune-related disorders, we examined Gas5 RNA levels in various autoimmune, inflammatory, and infectious diseases using the microarray data available in the Gene Expression Omnibus. We found that Gas5 levels were altered in whole blood or leukocytes of the patients with rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and sarcoidosis. Gas5 levels were also altered in infectious diseases, such as by the human immunodeficiency virus type-1 and influenza virus, and bacterial sepsis. In our experimental analysis using mice, Gas5 levels were kept at high basal levels and did not respond to fasting in immune organs, such as spleen and thymus, while its levels in metabolic organs, including liver, fat, and skeletal muscles, were low at baseline and were highly elevated upon this treatment, possibly through suppression of the mTOR pathway. These results suggest that Gas5 plays a role in the regulation of immune functions and pathogenesis/pathophysiology of autoimmune, inflammatory, and infectious diseases in part through modulation of the GR transcriptional activity via its decoy RNA "GRE". Changes in the Gas5 levels may also influence disease response to immunosuppressive glucocorticoid therapy.

Acute and chronic stress differentially regulate cyclin-dependent kinase 5 in mouse brain: implications to glucocorticoid actions and major depression.

Stress activates the hypothalamic-pituitary-adrenal axis, which in turn increases circulating glucocorticoid concentrations and stimulates the glucocorticoid receptor (GR). Chronically elevated glucocorticoids by repetitive exposure to stress are implicated in major depression and anxiety disorders. Cyclin-dependent kinase 5 (CDK5), a molecule essential for nervous system development, function and pathogenesis of neurodegenerative disorders, can modulate GR activity through phosphorylation. We examined potential contribution of CDK5 to stress response and pathophysiology of major depression. In mice, acute immobilized stress (AS) caused a biphasic effect on CDK5 activity, initially reducing but increasing afterwards in prefrontal cortex (PFC) and hippocampus (HIPPO), whereas chronic unpredictable stress (CS) strongly increased it in these brain areas, indicating that AS and CS differentially regulate this kinase activity in a brain region-specific fashion. GR phosphorylation contemporaneously followed the observed changes of CDK5 activity after AS, thus CDK5 may in part alter GR phosphorylation upon this stress. In the postmortem brains of subjects with major depression, CDK5 activity was elevated in Brodmann's area 25, but not in entire PFC and HIPPO. Messenger RNA expression of glucocorticoid-regulated/stress-related genes showed distinct expression profiles in several brain areas of these stressed mice or depressive subjects in which CDK5-mediated changes in GR phosphorylation may have some regulatory roles. Taken together, these results indicate that CDK5 is an integral component of stress response and major depression with regulatory means specific to different stressors, brain areas and diseases in part through changing phosphorylation of GR.

Expression profiles of the nuclear receptors and their transcriptional coregulators during differentiation of neural stem cells.

Neural stem cells (NSCs) are pluripotent precursors with the ability to proliferate and differentiate into 3 neural cell lineages, neurons, astrocytes and oligodendrocytes. Elucidation of the mechanisms underlying these biologic processes is essential for understanding both physiologic and pathologic neural development and regeneration after injury. Nuclear hormone receptors (NRs) and their transcriptional coregulators also play crucial roles in neural development, functions and fate. To identify key NRs and their transcriptional regulators in NSC differentiation, we examined mRNA expression of 49 NRs and many of their coregulators during differentiation (0-5 days) of mouse embryonic NSCs induced by withdrawal of fibroblast growth factor-2 (FGF2). 37 out of 49 NRs were expressed in NSCs before induction of differentiation, while receptors known to play major roles in neural development, such as THRα, RXRs, RORs, TRs, and COUP-TFs, were highly expressed. CAR, which plays important roles in xenobiotic metabolism, was also highly expressed. FGF2 withdrawal induced mRNA expression of RORγ, RXRγ, and MR by over 20-fold. Most of the transcriptional coregulators examined were expressed basally and throughout differentiation without major changes, while FGF2 withdrawal strongly induced mRNA expression of several histone deacetylases (HDACs), including HDAC11. Dexamethasone and aldosterone, respectively a synthetic glucocorticoid and natural mineralocorticoid, increased NSC numbers and induced differentiation into neurons and astrocytes. These results indicate that the NRs and their coregulators are present and/or change their expression during NSC differentiation, suggesting that they may influence development of the central nervous system in the absence or presence of their ligands.

Glucocorticoid receptor: implications for rheumatic diseases.

The glucocorticoid receptor (GR), a member of the nuclear receptor superfamily, mediates most of the known biologic effects of glucocorticoids. The human GR gene consists of 9 exons and expresses 2 alternative splicing isoforms, the GRα and GRß. GRα is the classic receptor that binds to glucocorticoids and mediates most of the known actions of glucocorticoids, while GRß does not bind to these hormones and exerts a dominant negative effect upon the GRα-induced transcriptional activity. Each of the two GR splice isoforms has 8 translational variants with specific transcriptional activity and tissue distribution. GRα consists of three subdomains, translocates from the cytoplasm into the nucleus upon binding to glucocorticoids, and regulates the transcriptional activity of numerous glucocorticoid-responsive genes either by binding to its cognate DNA sequences or by interacting with other transcription factors. In addition to these genomic actions, the GR also exerts rapid, non-genomic effects, which are possibly mediated by membrane-localised receptors or by translocation into the mitochondria. All these actions of the GR appear to play an important role in the regulation of the immune system. Specifically, the splicing variant GRß may be involved in the pathogenesis of rheumatic diseases, while the circadian regulation of the GR activity via acetylation by the Clock transcription factor may have therapeutic implications for the preferential timing of glucocorticoid administration in autoimmune inflammatory disorders.

Tissue glucocorticoid sensitivity: beyond stochastic regulation on the diverse actions of glucocorticoids.

Glucocorticoids have a broad array of life-sustaining functions, such as for the maintenance of the basal- and stress-related organ homeostasis. They are also frequently used as therapeutic compounds for many pathologic conditions. Thus, changes of tissue sensitivity to glucocorticoids play important roles in the physiologic conditions and are associated with and influence the course of numerous pathologic states. Changes in tissue glucocorticoid sensitivity may present on either side of an optimal range, respectively as glucocorticoid resistance or hypersensitivity, and may be generalized or tissue-specific. Recent insights into the mechanisms of the glucocorticoid receptor (GR) action indicated that the glucocorticoid signaling system is highly stochastic. Indeed, numerous factors contribute to the hormonal action at each step of the GR signaling cascade, such as ligand availability, receptor isoform expression, intracellular circulation, promoter association, attraction of cofactors, and finally clearance of the receptor from the target genes. Importantly, these regulatory mechanisms appear to be functional in tissue-, gene- and cellular biologic state-specific fashions. As an example of such phase-specific factors, we discussed influence of the cyclin-dependent kinase 5 to the GR transcriptional activity, which specifically functions in the central nervous system and may thus play an important role in the regulation of glucocorticoid action in this organ.

Novel causes of generalized glucocorticoid resistance.

Glucocorticoid resistance is a rare condition characterized by generalized, partial, target-tissue insensitivity to glucocorticoids. Compensatory elevations in circulating adrenocorticotropic hormone (ACTH) concentrations lead to increased secretion of cortisol and adrenal steroids with mineralocorticoid and/or androgenic activity, but no clinical evidence of hypercortisolism. The clinical spectrum of the condition is broad, ranging from asymptomatic to severe cases of hyperandrogenism, fatigue and/or mineralocorticoid excess. The molecular basis of glucocorticoid resistance has been ascribed to mutations in the human glucocorticoid receptor (hGR) gene, which impair glucocorticoid signal transduction, thereby altering tissue sensitivity to glucocorticoids. The study of functional defects of natural hGR mutants enhances our understanding of the molecular mechanisms of hGR action and highlights the importance of integrated cellular and molecular signaling mechanisms for maintaining homeostasis and preserving normal physiology.

The PPARdelta agonist GW501516 suppresses interleukin-6-mediated hepatocyte acute phase reaction via STAT3 inhibition.

BACKGROUND: Interleukin-6 and downstream liver effectors acute phase reactants are implicated in the systemic inflammatory reaction. Peroxisome proliferator-activated receptor delta (PPARdelta), which binds to and is activated by a variety of fatty acids, was recently shown to have anti-inflammatory actions. MATERIALS AND METHODS: We examined the ability of the synthetic PPARdelta agonist GW501516 to suppress interleukin-6-induced expression of acute phase proteins in human hepatoma HepG2 cells and rat primary hepatocytes. Results GW501516 dose-dependently suppressed interleukin-6-induced mRNA expression of the acute phase protein alpha1-antichymotrypsin in HepG2 cells. The compound also suppressed interleukin-6-induced mRNA expression of alpha2-acid glycoprotein, beta-fibrinogen and alpha2-macroglobulin in and the secretion of C-reactive protein by rat primary hepatocytes. Depletion of the PPARdelta receptor, but not of PPARalpha or gamma, attenuated the suppressive effect of GW501516 on interleukin-6-induced alpha1-antichymotrypsin mRNA expression, indicating that PPARdelta specifically mediated this effect. Since interleukin-6 stimulates the transcriptional activity of the alpha1-antichymotrypsin promoter by activating the signal transducer and activator of transcription (STAT) 3, we examined functional interaction of this transcription factor and PPARdelta on this promoter. Overexpression of PPARdelta enhanced the suppressive effect of GW501516 on STAT3-activated transcriptional activity of the alpha1-antichymotrypsin promoter, while GW501516 suppressed interleukin-6-induced binding of this transcription factor to this promoter. CONCLUSIONS: These findings indicate that agonist-activated PPARdelta interferes with interleukin-6-induced acute phase reaction in the liver by inhibiting the transcriptional activity of STAT3. PPARdelta agonists might be useful for the suppression of systemic inflammatory reactions in which IL-6 plays a central role.

Statin-induced blockade of prenylation alters nucleocytoplasmic shuttling of GTP-binding proteins gamma2 and beta2 and enhances their suppressive effect on glucocorticoid receptor transcriptional activity.

BACKGROUND: We previously reported that the guanine tri-phosphate-binding proteins (G) beta and gamma are both localized in the nucleus, in addition to their expected cytoplasmic/plasma membrane localization. These proteins, as a heterodimeric complex, suppress glucocorticoid response element-mediated transcriptional activity of the glucocorticoid receptor through direct physical interactions between Gbeta and the glucocorticoid receptor. MATERIALS AND METHODS: As Ggamma is prenylated at a cysteine residue in its C-terminal portion, and as this post-translational modification is required for many of the known Gbeta/Ggamma activities, we examined the effect of its absence or diminution on Gbeta/Ggamma-induced suppression of glucocorticoid receptor-induced transcriptional activity. RESULTS: In a functional reporter assay, Ggamma2C68S, which is defective at the prenylation site, was more potent than the wild-type Ggamma2 at increasing Gbeta2-induced suppression of glucocorticoid receptor transactivation. Interestingly, the enhanced green fluorescent protein fusion of this mutant Ggamma2 was localized preferentially in the nucleus, while it was absent from the plasma membrane. Lovastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor that abrogates the prenylation of Ggamma, shifted the subcellular localization of enhanced green fluorescence protein-fused Ggamma2 and Gbeta2 from the cytoplasm/plasma membrane to the nucleus and further suppressed glucocorticoid receptor-induced transcriptional activity. CONCLUSIONS: These findings indicate that not only is the natural covalent addition of the prenyl residue to Ggamma unnecessary for the transcriptional suppression induced by Gbeta/Ggamma on the glucocorticoid receptor, but rather helps retain the Gbeta/Ggamma complex away from the nucleus decreasing its antiglucocorticoid actions.

Pituitary homeobox factor 1, a novel transcription factor in the adrenal regulating steroid 11beta-hydroxylase.

Pituitary homeobox 1 (Ptx1/Pitx1) is a homeodomain-containing transcription factor present throughout pituitary development. Ptx1/Pitx1 interacts with steroidogenic factor 1 (SF-1) in the regulation of pituitary gene expression. SF-1 also plays a critical role in the transcription of enzymes involved in adrenal steroidogenesis. Therefore, we analyzed the presence and role of Ptx1/Pitx1 in human adrenal cortex. Both Ptx1/Pitx1 and SF-1 mRNA were expressed in the human adrenal gland, and immuno-electron microscopy demonstrated the presence of Ptx1/Pitx1 protein in the nucleus of adrenocortical cells. Computer analysis revealed the presence of Ptx1/Pitx1 signal sequences within the promoter region of human 11beta hydroxylase ( hCYP11B1). To examine the role of Ptx1/Pitx1 in the regulation of the genes, we prepared reporter constructs using the 5'-flanking DNA of the hCYP11B1 gene and transfected them into Y-1 mouse adrenocortical cells, HeLa and CV-1 cells. Ptx1/Pitx1 stimulation of hCYP11B1 reporter activity (3-fold over basal) in Y-1 cells was equal to that observed with SF-1. The hCYP11B1 promoter activity in Y-1 cells was not synergistically increased by co-transfection with both Ptx1/Pitx1 and SF-1. Both basal and ACTH-stimulated hCYP11B1 reporter activities in Y-1 cells were increased by co-transfection with either Ptx1/Pitx1 or SF-1 expression vectors. In contrast, co-transfection with both Ptx1/Pitx1 and SF-1 synergistically increased hCYP11B1 promoter activity in HeLa and CV-1 cells (5-fold and 20-fold over basal, respectively). In conclusion, this study represents the first demonstration for a role of Ptx1/Pitx1 in the regulation of transcription of enzymes involved in adrenal steroidogenesis.

AIDS-related lipodystrophy/insulin resistance syndrome.

The recent development and clinical use of three different types of highly effective anti-HIV-1 drugs, including nucleotide and non-nucleotide reverse transcriptase inhibitors (NRTIs) and non-peptidic viral protease inhibitors (PIs) and their combinations, termed highly active antiretroviral therapy (HAART), have dramatically reduced the infection-related mortality of AIDS patients in developed countries. However, the prolongation of the life expectancy of HIV-1-infected patients and/or long-term use of the above antiviral agents have generated a score of new problems and complications. Among them is the relatively common AIDS-related lipodystrophy/insulin resistance syndrome, which is associated with severe metabolic disturbances such as carbohydrate intolerance/diabetes mellitus and severe dyslipidemia, which influence the quality of life and threaten the life expectancies of HIV-1-infected patients by increasing the risk of atherosclerotic cardiovascular disease. The etiology of this syndrome appears to be multi-factorial; the classes of anti-viral drugs listed above, hypercytokinemia in AIDS patients, and the HIV-1 infection itself could induce the pathologic changes of this syndrome or increase the vulnerability of patients to the adverse effect of the therapeutic compounds. In this article, we review our current understanding of the pathogenesis of this severe AIDS-associated metabolic disorder.

Expression of lymphocyte-specific chemokines in human malignant glioma: Essential role of LARC in cellular immunity of malignant glioma.

Lymphocytes are frequently observed in human malignant glioma, the mechanism(s) underlying their appearance is not fully understood. To clarify tumor immunity in malignant gliomas, we analyzed the expression of 8 novel lymphocyte-specific chemokines in human glioma cell lines and glioma tissues by RT-PCR, Northern blot, immunoblot and immunohistochemistry, and examined the correlation with the infiltration of various subsets of lymphocytes. For the 8 chemokines examined (LARC, TARC, ELC, SLC, PARC, LEC, HCC-2, and SCM-1alpha), expression of LARC was clearly detectable in all 12 glioma cell lines by RT-PCR. Additionally, expression of TARC and SCM-1alpha was detectable in the majority of glioma cell lines. However, the expression level of most chemokines was low, so that Northern blot analysis could not demonstrate their expression with the exception of LARC in 2 cell lines. Expression of LARC mRNA and LARC protein was strongly induced by phorbol myristate ester in U87 MG cells. The production of LARC protein was demonstrated in 4 of 8 glioblastoma tissues by immunoblotting, and 9 of 33 samples (27.3%) by immunohistochemistry. Interestingly, the positivity of LARC staining was significantly correlated with the infiltration of CD8-, CD4-, and CD45R0-positive cells (p<0.001). Although the constitutive expression level of LARC is low, certain stimulations could strongly induce its expression, and play a crucial role in the tumor immunity of human malignant glioma.

Pathologic human GR mutant has a transdominant negative effect on the wild-type GR by inhibiting its translocation into the nucleus: importance of the ligand-binding domain for intracellular GR trafficking.

The syndrome of familial or sporadic glucocorticoid resistance is characterized by hypercortisolism without the clinical stigmata of Cushing syndrome. This condition is usually caused by mutations of the human GR, a ligand-activated transcription factor that shuttles between the cytoplasm and the nucleus. A pathological human mutant receptor, in which Ile was replaced by Asn at position 559, had negligible ligand binding, was transcriptionally extremely weak, and exerted a transdominant negative effect on the transactivational activity of the wild-type GR, causing severe glucocorticoid resistance in the heterozygous state. To understand the mechanism of this mutant's trans-dominance, we constructed several N-terminal GR fusion chimeras to green fluorescent protein (GFP) and demonstrated that their transactivational activities were similar to those of the original proteins. The GFP-human (h) GRalphaI559N chimera was predominantly localized in the cytoplasm, and only high doses or prolonged glucocorticoid treatment triggered complete nuclear import that took 180 vs. 12 min for GFP-hGRalpha. Furthermore, hGRalphaI559N inhibited nuclear import of the wild-type GFP-hGRalpha, suggesting that its trans-dominant activity on the wild-type receptor is probably exerted at the process of nuclear translocation. As the ligand-binding domain (LBD) of the GR appears to play an important role in its nucleocytoplasmic shuttling, we also examined two additional GR-related fusion proteins. The natural hGR isoform beta (GFP-hGRbeta), containing a unique LBD, was transactivation-inactive, moderately trans-dominant, and localized instantaneously and predominantly in the nucleus; glucocorticoid addition did not change its localization. Similarly, GFP-hGR514, lacking the entire LBD, was instantaneously and predominantly localized in the nucleus regardless of presence of glucocorticoids. Using a cell fusion system we demonstrated that nuclear export of GFP-hGRalphaI559N (250 min) and GFP-hGRbeta (300 min) was drastically impaired compared with that of GFP-hGRalpha (50 min) and GFP-hGR514 (50 min), suggesting that an altered LBD may impede the exit of the GR from the nucleus. We conclude that the trans-dominant negative effect of the pathological mutant is exerted primarily at the translocation step, whereas that of the natural isoform beta is exerted at the level of transcription.

Identification of the cis-acting region in the NF2 gene promoter as a potential target for mutation and methylation-dependent silencing in schwannoma.

BACKGROUND: Although mutational inactivation and allelic loss in the NF2 gene appear to be causal events in the majority of vestibular schwannomas, involvement of another potentially important mechanism, transcriptional inactivation, has not been investigated. RESULTS: We cloned and functionally characterized the 5'-flanking region of the human NF2 gene and identified the molecular mechanisms that regulate NF2 expression. Luciferase assay and site-directed mutagenesis demonstrated that a 70-base pair (bp) region (-591 to -522 bp from the translation start site) was essential for the basic expression of the NF2 gene. A gel mobility shift assay indicated recognition by nuclear protein of the unusually long ( approximately 66 bp) sequences in this region. Recognition was inhibited by either mutation of the binding core sequence or by methylation of three CpG sites. Point mutations at these CpG sites significantly decreased promoter activity, suggesting the importance of these sites. In 14 of 23 vestibular schwannomas, these three CpG sites were methylated in a site-specific manner and the methylation status was consistent with the expression of NF2 mRNA. CONCLUSIONS: Suppressed expression by aberrant methylation or mutation of the promoter elements could be an alternative mechanism for inactivation of the NF2 gene.

Glucocorticoid and mineralocorticoid resistance/hypersensitivity syndromes.

Glucocorticoids and mineralocorticoids regulate diverse functions important to maintain central nervous system, cardiovascular, metabolic, and immune homeostasis. The actions of these hormones are mediated by their specific intracellular receptors: the glucocorticoid (GR) and mineralocorticoid (MR) receptors. Pathologic conditions associated with changes of tissue sensitivity to these hormones have been described. The syndrome of familial glucocorticoid resistance is characterized by hypercortisolism without Cushing's syndrome stigmata. The molecular defects of four kindreds and one sporadic case have been elucidated as inactivating mutations in the ligand-binding domain of GR. Two cases developed glucocorticoid resistance at the heterozygous state. In these patients, mutant receptors possessed transdominant negative activity upon the wild type receptor. Insensitivity to mineralocorticoids (which may also be caused by loss of function mutations of the MR gene) was found in one sporadic case and four autosomal dominant cases of Pseudohypoaldosteronism type 1. These included two frameshift mutations and a premature termination codon in exon 2, leading to gene products lacking the entire DNA- and ligand-binding domains, and a single base-pair deletion in the intron-5 splice donor site. Tissue hypersensitivity to glucocorticoids was recently hypothesized in patients with Human Immunodeficiency Virus (HIV) type-1 infection via the accessory proteins Vpr and Tat which enhance GR transactivation. Since HIV-1 long terminal repeat (LTR) and glucocorticoid-responsive promoters use the same set of coactivators, these proteins may stimulate HIV-1-LTR and glucocorticoid-inducible genes concurrently. The former may directly stimulate viral proliferation, while the latter may indirectly enhance viral propagation by suppressing the host immune system through glucocorticoid-mediated mechanisms.

FR198248, a new anti-influenza agent isolated from Apsergillus terreus No 13830. I. Taxomony, fermentation, isolation, physico-chemical properties and biological activities.

A novel anti-influenza agent, FR198248, was isolated from the cultured broth of a fungal strain No.13830. The strain was identified as Aspergillus terreus from morphological characteristics. FR198248, a new type of hydroxyl benzaldehyde compound, showed antiinfluenza virus activity in Madin-Darby canine kidney (MDCK) cells in vitro. The mode of action of FR198248 against influenza virus A could be ascribed to an inhibitory effect on the stage of virus adsorption. Furthermore, FR198248 possessed potent in vivo anti-influenza activity in a murine model of respiratory tract infection.

Randomized comparison of intra-arterial versus intravenous infusion of ACNU for newly diagnosed patients with glioblastoma.

This prospective randomized trial was performed to compare the effectiveness of intra-arterial ACNU with intravenous ACNU in newly diagnosed patients with supratentorial glioblastoma. The primary end points were overall survival and progression-free survival. Within 3 weeks after surgery, patients were randomly assigned to receive either intravenous or intra-arterial ACNU (80 mg/m2) once every 6 weeks concomitant with radiotherapy. Intraarterial ACNU was administered for the first 3 courses followed by intravenous administration. Eighty-four patients were enrolled onto this study and among them 82 patients who passed eligibility criteria were analyzed. Patients characteristics were not different significantly between 2 treatment arms. Median survival and progression-free survival time was 59 and 24 weeks, respectively for intra-arterial arm and 56 and 45 weeks, respectively for intravenous arm. There was no significant difference respectively between two treatment arms. Among the prognostic variables including age, Karnofsky performance status, extent of surgery and treatment arm, Cox's proportional hazards model showed that age was the only significant factor for both survival and progression-free survival (P = 0.003 and 0.016, respectively). With regard to toxicity, there was no significant difference between two treatment arms. Leukoencephalopathy was not observed in intra-arterial arm. In conclusion, intra-arterial ACNU when administered by the method in this study does not increase the survival and progression-free survival of newly diagnosed patients with glioblastoma over that afforded by intravenous ACNU.

Low glucocorticoid receptor alpha/beta ratio in T-cell lymphoblastic leukemia.

Glucocorticoid therapy is pivotal in the treatment of acute lymphoblastic leukemia (ALL); it reduces cell proliferation, promotes cell cycle arrest, and induces cell death by apoptosis. The sensitivity of leukemic cells to glucocorticoids was previously related to the cell concentration of 3[H]dexamethasone-binding sites. The latter represents the classic glucocorticoid receptor (GR) isoform alpha that binds ligand and modulates the transcription rates of glucocorticoid-responsive genes. In ALL, lymphoblasts of T-lineage are less sensitive to glucocorticoids than cells of the B-lineage. The alternatively spliced GR isoform (GRP), which exerts a dominant negative effect on GRalpha-mediated transcriptional activity, has been proposed as a possible mediator of glucocorticoid resistance. In this study, we determined the amount of GRalpha and GRbeta in mononuclear cells from 13 newly diagnosed and untreated children with ALL and 9 controls by quantitative Western analysis. Generally, leukemic patients expressed 6 times less GRalpha (ALL= 0.54 +/- 1.1; controls = 3.1 +/- 0.9; p < 0.01) than controls, but the same amount of GRbeta (ALL=3.62 +/- 3.3; controls = 3.6 +/- 3.4). ALL patients with T-cell disease had a much lower GRalpha (0.09 +/- 0.1; p < 0.01) but a similar or slightly higher GRbeta (5.98 +/- 3.9; p = 0.1) expression than controls, with a GRalpha/GRbeta ratio 15 times smaller than controls. Mononuclear leukocytes of T-cell lineage expressed significantly lower GRalpha (p = 0.04) and higher GRbeta (p < 0.01) than cells of the pre-B immunophenotype, with a 10 times smaller ratio. We conclude that the combination of low GRalpha and normal-to-high GRbeta expression in leukemic lymphoblasts might represent one of the mechanisms responsible for their reduced glucocorticoid sensitivity; this is more pronounced in T-lineage cells.

Gene delivery with optimized electroporation parameters shows potential for treatment of gliomas.

Electroporation, a standard laboratory method of introducing exogenous molecules into cells, has been gaining importance as a very effective non-viral physical technique of gene delivery. In this study, we have used subcutaneous model of the C6 rat glioma cells and established an optimal condition to obtain very high gene expression in tumor tissues using both reporter and functional genes. Tumors grown on the flanks of Wistar rats are exposed and directly injected with plasmid DNA having the constructs of luciferase, green fluorescent protein and, the fragment of the diphtheria toxin, DT-A. The tumors are then subjected to square wave pulses from an electroporator. Gene expression is found to be several orders of magnitude higher when the tumors are pulsed with the optimized electrical parameters compared to the controls. For luciferase, the enhancement is approximately 135-fold, for the green fluorescent protein, gene expression is seen over a wide area within the sections examined, as contrast to a few punctate dots in the control specimens, and finally, DT-A shows massive death in the tumor tissue. A special circular array of six needles through which pulses are delivered with rotating electric field is found to be highly efficient in transferring genes inside the tumor. Direct injection of plasmid DNA followed by electroporation allows very high in vivo gene transfer and its subsequent expression into tumor tissues. This method may be applicable to any solid tumor.