Glucocorticoid-binding proteins in human acute lymphoblastic leukemic blast cells

Of numbers and movement - understanding transcription factor pathogenesis by advanced microscopy

Transcription factors (TFs) are life-sustaining and, therefore, the subject of intensive research. By regulating gene expression, TFs control a plethora of developmental and physiological processes, and their abnormal function commonly leads to various developmental defects and diseases in humans. Normal TF function often depends on gene dosage, which can be altered by copy-number variation or loss-of-function mutations. This explains why TF haploinsufficiency (HI) can lead to disease. Since aberrant TF numbers frequently result in pathogenic abnormalities of gene expression, quantitative analyses of TFs are a priority in the field. In vitro single-molecule methodologies have significantly aided the identification of links between TF gene dosage and transcriptional outcomes. Additionally, advances in quantitative microscopy have contributed mechanistic insights into normal and aberrant TF function. However, to understand TF biology, TF-chromatin interactions must be characterised in vivo, in a tissue-specific manner and in the context of both normal and altered TF numbers. Here, we summarise the advanced microscopy methodologies most frequently used to link TF abundance to function and dissect the molecular mechanisms underlying TF HIs. Increased application of advanced single-molecule and super-resolution microscopy modalities will improve our understanding of how TF HIs drive disease.

High-Dose Medroxyprogesterone Acetate (MPA) Treatment in Advanced Breast Cancer. A Review

Medroxyprogesterone acetate (MPA) when employed at high doses ≥ 500 ≤ 1000 mg/day i.m.) can produce objective remission with improved survival in about 30% of postmenopausal women with advanced breast cancer resistant to cytotoxic drugs and endocrine therapies. When administered to women not previously treated with chemotherapy, the objective remission response rate reached 40%. From available evidence, high dose MPA can be considered a useful agent in the treatment of advanced breast cancer in postmenopausal women with soft tissue, pulmonary, pleural or osseous involvement even when patients have become refractory to prior hormone and cytotoxic therapies. Early results suggest that the response rate can be increased in patients with estrogen and/or progesterone-positive receptors. It is note worthy that in a study conducted on postmenopausal women resistant to cytotoxic and/or hormonal drugs, the median duration of survival was 13.5 months, while CRs plus PRs did not reach the median at 24 months after starting MPA treatment. High dose MPA is essentially devoid of major side effects. Relief of pain, increase in appetite and body weight, and sense of well being are characteristic features of the improved quality of life under MPA treatment. However, a gluteal abscess (from 2% to 20% dose related) is the most frequent side effect. A promising area for future studies is combined therapy using hormonal and cytotoxic agents or alternating sequential combinations. Well-designed studies are needed to develop means for increasing the complete response rate and therefore survival. Recent studies of combined chemo-and hormonal (MPA) therapy have yielded objective tumor regressions of 53 to 80% with an increased rate of complete remissions and duration of response.

Estrogen and Progesterone Binding Proteins in Human Colorectal Cancer. A Preliminary Characterization of Estradiol Receptor

Estradiol receptor (ER) and progesterone receptor (PgR) were assayed in tumors from 20 patients with primary colorectal cancer. Ten of 20 tumors contained high affinity sites for 17β-estradiol and progesterone. The highest concentration of ER was 56 fmol/mg of protein. The ER dissociation constant ranged from 1.6 × 10−10 M to 8 × 10−10 M (mean 4.6 ± 2.6). The highest concentration of PgR was 42 fmol/mg of protein. The PgR dissociation constant ranged from 3 × 10−9 to 9 × 10−9 M (mean 5.65 ± 2.1). Four out of 20 specimens analyzed were from male patients and all resulted negative for both receptors. Sixty per cent of ER positive tumors were also PgR positive, whereas only 20 % of ER negative were PgR positive. Sucrose gradient centrifugation showed that cytoplasmic ER of colorectal cancer sedimented at 3 S in the absence of protease inhibitors and at 4.5 S in the presence of 1 mM phenylmethylsulphonyl fluoride (PMSF) both in low and in high ionic strength. When chromatographed on Sephadex G-200 almost all ER was quantitatively recovered in the included fractions. Molecular weights of ER eluted from Sephadex G-200 ranged from 90,000 to 50,000 daltons. Elution profile and molecular weight heterogeneity suggest that, in spite of the presence of PMSF, there is a limited proteolysis of ER. Partially purified colorectal cancer ER did not bind to sepharose-heparin. The isoelectric point of ER was 6.4–6.5.

Common variants of the mineralocorticoid and glucocorticoid receptor genes may contribute to pregnancy-related anxiety: a pilot study

The hypothalamic-pituitary-adrenal (HPA) axis overactivity is thought to contribute to increased vulnerability to maternal stress. We hypothesize that functionally relevant polymorphic variants of the glucocorticoid (NR3C1) and mineralocorticoid (NR3C2) receptor genes mediating biological effects of cortisol, a major stress hormone, could also modulate the capacity to cope with pregnancy-related anxiety. Genomic DNA from the blood of 42 women with pregnancy-related anxiety and 42 age-matched women with normal pregnancy (5–6th months of gestation) were genotyped for markers rs6195 and rs10482605 of NR3C1 and two NR3C2 polymorphisms (rs5522 and rs2070951) using a Taqman allele discrimination assay. Serum total cortisol was measured using an ELISA technique. The allele Ser363 of rs6195 (the N363S polymorphism of NR3C1) was found to be associated with a higher risk of maternal stress (odds ratio (OR)=5.27; P=0.001). For NR3C2, the allele Val180 of rs5522 (I180V) also showed association with increased risk of neonatal stress (OR=1.97; P=0.038). Both predisposing gene variants were also associated with significantly elevated levels of cortisol in normally pregnant women and females with pregnancy-related anxiety. Our results suggest that pregnancy-related anxiety can be modulated by variants of NR3C1 and NR3C2 associated with increased basal cortisol levels. Thus, our findings provide evidence in support of the suggestion that elevated cortisol levels and HPA axis hyperactivity are implicated in pregnancy-related anxiety.

Glucocorticoid use in acute lymphoblastic leukaemia

Glucocorticoids (prednisone and dexamethasone) play an essential part in the treatment of acute lymphoblastic leukaemia (ALL), but their optimum doses and bioequivalence have not been established. Results of preclinical studies have shown that dexamethasone has a longer half-life and better CNS penetration than does prednisone. In prospective randomised trials, dexamethasone improved control of CNS leukaemia. At a prednisone-to-dexamethasone dose ratio of less than seven, dexamethasone (6-18 mg/m(2) per day) resulted in a better event-free survival than did prednisone (40-120 mg/m(2) per day), and high-dose dexamethasone (10-18 mg/m(2) per day) improved the outcome of T-cell ALL and high-risk ALL. However, dexamethasone caused more adverse effects, including infection, bone fracture, osteonecrosis, mood and behaviour problems, and myopathy. At a dose ratio greater than seven, the two drugs showed no difference in efficacy. Therefore, the efficacy of prednisone and dexamethasone is dose dependent and needs to be carefully assessed against the toxic effects. Moreover, although dexamethasone generally showed increased activity in ALL cells in vitro, the dose ratio of the two drugs that exerted equivalent cytotoxic effects differed substantially in samples from individuals. The selection of the type and dose of glucocorticoid should be based on the risk of relapse, treatment phase, and the chemotherapeutic drugs used concomitantly.

Intermittent melphalan and prednisolone therapy in plasma cell myeloma

Thirty-two consecutive, previously untreated patients with plasma cell myeloma were treated with 4-day courses of melphalan (0.25 mg/kg/day) and prednisolone (2 mg/kg/day) every sixth week. The observation period ranged from 26 to 75 months and the total median survival time was 29 months. 75% of the patients responded to therapy and their median survival time was 42 months. Sex did not influence either the response rate or the survival time. Most patients were treated in an out-patient clinic and required a minimum of check-ups.

Glucocorticoid binding and cytolethal responsiveness of hairy-cell and chronic lymphocytic leukaemia

The glucocorticoid binding properties and cytolethal responsiveness of leukaemic cells were studied in vitro in seven patients with hairy-cell leukaemia (HCL) and five with chronic lymphocytic leukaemia (CLL). Substantial levels of glucocorticoid binding were detected both in whole cell and cytosol preparations from all patients although the level of binding by HCL cells always exceeded that of CLL cells (P less than 0.05). In both leukaemic cell types the uptake and binding of prednisolone in vitro was significantly greater than that of dexamethasone (P less than 0.05). CLL cells showed a variable dose-related cytolethal response to methylprednisolone sodium succinate (MPSS) treatment in vitro although cytolytic effects were not marked in the usual pharmacological dose range (10(-5)-10(-6)M). Treatment of CLL patients with conventional doses of prednisone for extended periods or high intravenous infusions of MPSS over shorter periods had no consistent effect on the in-vitro level of steroid binding or the cytolethal responsiveness of CLL cells to glucocorticoid treatment. Although HCL cells proved highly resistant to the cytolethal effects of MPSS in vitro, the substantial binding of glucocorticoids by leukaemic cells from all HCL patients indicates the potential value of steroid therapy in this disease should be explored further.

Dexamethasone-induced apoptosis of thymocytes: role of glucocorticoid receptor-associated Src kinase and caspase-8 activation

Glucocorticoid hormones (GCHs) regulate normal and neoplastic lymphocyte development by exerting antiproliferative and/or apoptotic effects. We have previously shown that dexamethasone (DEX)-activated thymocyte apoptosis requires a sequence of events including interaction with the glucocorticoid receptor (GR), phosphatidylinositol-specific phospholipase C (PI-PLC), and acidic sphingomyelinase (aSMase) activation. We analyzed the mechanisms of GCH-activated apoptosis by focusing on GR-associated Src kinase, cytochrome c release, and caspase-8, -9, and -3 activation. We show here that PI-PLC binds to GR-associated Src kinase, as indicated by coimmunoprecipitation experiments. Moreover, DEX treatment induces PI-PLC phosphorylation and activation. DEX-induced PI-PLC phosphorylation, activation, and apoptosis are inhibited by PP1, a Src kinase inhibitor, thus suggesting that Src-mediated PI-PLC activation is involved in DEX-induced apoptosis. Caspase-9, -8, and -3 activation and cytochrome c release can be detected 1 to 2 hours after DEX treatment. Caspase-9 inhibition does not counter cytochrome c release, caspase-8 and caspase-3 activation, and apoptosis. Caspase-8 inhibition counters cytochrome c release, caspase-9 and caspase-3 activation, and apoptosis, thus suggesting that caspase-8 inhibitor can directly inhibit caspase-9 and/or that DEX-induced caspase-8 activation is upstream to mitochondria and can regulate caspase-3 directly or through cytochrome c release and the consequent caspase-9/caspase-3 activation. DEX-induced caspase-8 activation, like ceramide-induced caspase-8 activation, correlates with the formation of Fas-associated death domain protein (FADD)/caspase-8 complex. Caspase-8 activation is countered by the inhibition of macromolecular synthesis and of Src kinase, PI-PLC, and aSMase activation, suggesting it is downstream in the DEX-activated apoptotic pathway of thymocytes.

Toxicity, supportive care and costs of two chemotherapy protocols for treatment of childhood ALL in Russia: BFM 90m and MB 91

Since the late 1980s, polychemotherapy protocols for the treatment of childhood acute lymphoblastic leukaemia (ALL) derived from Western European and American regimens have been introduced in Russian paediatric oncology centres. Whereas treatment results were significantly improved compared with the results of former non-standard treatment strategies, the substantial toxicity of these protocols required a high standard of supportive care, and the high costs of treatment became a major problem. In 1991, a new protocol was developed with the aim of reducing toxicity and costs without affecting efficacy of the treatment. Since 1991, a single-centre study comparing the new Russian Protocol, Moscow-Berlin 91 (MB), with a modified version of the protocol ALL BFM 90 (BFM) of the Berlin-Frankfurt-Münster group was performed in Moscow to evaluate possible advantages of the new protocol under Russian conditions. The aim of the present analysis was to compare toxicity, need of supportive care and expense of both regimens (BFM, 25 pts; MB, 32 pts). Hepatotoxicity (liver enzymes), nephrotoxicity (creatinine), duration of neutropenia, and platelet transfusions were similar in both protocols. The median erythrocyte transfusion level was greater in the BFM (1000 ml/m2) than the MB patients (505 ml/m2, P < 0.01), as was the length of intravenous (i.v.) antibiotic therapy (22 days BFM versus 9 days MB, P < 0.01), treatment delays (39 days BFM versus 21 days MB, P < 0.001), and duration of in-patient treatment (47 days BFM versus 18 days MB, P < 0.001). Side-effects of the MB protocol occurred mainly during induction therapy. Total costs (mean cost/person/m2 body surface) of treatment including supportive care were 1.73-fold higher for the BFM protocol than MB, whereas costs of cytostatic drugs were comparable in both groups. In Russia both protocols were feasible. During consolidation therapy tolerance to treatment was better in MB 91 compared with BFM 90m, whereas toxicity during induction therapy was similar in both protocols. With respect to costs and side-effects, the MB 91 protocol appears to be an alternative to established protocols for countries with limited financial and clinical resources.

Dexamethasone-Induced Thymocyte Apoptosis: Apoptotic Signal Involves the Sequential Activation of Phosphoinositide-Specific Phospholipase C, Acidic Sphingomyelinase, and Caspases

Glucocorticoid hormones (GCH) have been implicated as regulators of T-lymphocyte growth and differentiation. In particular, it has been reported that GCH can induce thymocyte apoptosis. However, the molecular mechanisms responsible for this GCH-induced death have not been clarified. In this work, the biochemical events associated with apoptosis induced by Dexamethasone (Dex), a synthetic GCH, in normal mouse thymocytes, have been analyzed. Results indicate that Dex-induced thymocyte apoptosis is attributable to an early ceramide generation caused by the activation of an acidic sphingomyelinase (aSMase). Caspase activity plays a crucial role in Dex-induced apoptosis and is downstream the aSMase activation in that inhibition of the early ceramide generation inhibits caspase activation and thymocyte death. Moreover, Dex treatment rapidly induces diacylglycerol (DAG) generation, through a protein kinase C (PKC) and G-protein–dependent phosphatidylinositol-specific phospholipase C (PI-PLC), an event which precedes and is required for aSMase activation. Indeed, PI-PLC inhibition by U73122 totally prevents Dex-induced aSMase activity, ceramide generation, and consequently, caspase activation and apoptosis. All these effects require Dex interaction with GCH receptor (GR), are countered by the GR antagonist RU486, and precede the GCH/GR-activated transcription and protein synthesis. These observations indicate that GCH activates thymocyte death through a complex signaling pathway that requires the sequential activation of different biochemical events.

Dexamethasone-Induced Thymocyte Apoptosis: Apoptotic Signal Involves the Sequential Activation of Phosphoinositide-Specific Phospholipase C, Acidic Sphingomyelinase, and Caspases

Glucocorticoid hormones (GCH) have been implicated as regulators of T-lymphocyte growth and differentiation. In particular, it has been reported that GCH can induce thymocyte apoptosis. However, the molecular mechanisms responsible for this GCH-induced death have not been clarified. In this work, the biochemical events associated with apoptosis induced by Dexamethasone (Dex), a synthetic GCH, in normal mouse thymocytes, have been analyzed. Results indicate that Dex-induced thymocyte apoptosis is attributable to an early ceramide generation caused by the activation of an acidic sphingomyelinase (aSMase). Caspase activity plays a crucial role in Dex-induced apoptosis and is downstream the aSMase activation in that inhibition of the early ceramide generation inhibits caspase activation and thymocyte death. Moreover, Dex treatment rapidly induces diacylglycerol (DAG) generation, through a protein kinase C (PKC) and G-protein–dependent phosphatidylinositol-specific phospholipase C (PI-PLC), an event which precedes and is required for aSMase activation. Indeed, PI-PLC inhibition by U73122 totally prevents Dex-induced aSMase activity, ceramide generation, and consequently, caspase activation and apoptosis. All these effects require Dex interaction with GCH receptor (GR), are countered by the GR antagonist RU486, and precede the GCH/GR-activated transcription and protein synthesis. These observations indicate that GCH activates thymocyte death through a complex signaling pathway that requires the sequential activation of different biochemical events.

Effect of long-term corticosteroid therapy on monocyte chemotaxis in man

The influence of prednisolone on monocyte chemotactic activity in vitro at prednisolone concentrations comparable with those achieved in man following oral dosage has been investigated. Chemotactic activity of monocytes from each of sixteen normal subjects was suppressed by concentrations of prednisolone as low as 25 ng/ml (suppression of chemotaxis, 20%). Maximal suppression occurred at 100 ng/ml (suppression of chemotaxis, 48%) and no significant increase in suppression was produced by increasing the concentration to 200 ng/ml (suppression of chemotaxis, 53%). In contrast, monocytes isolated from ten patients receiving corticosteroid therapy showed no significant suppression of chemotactic activity when exposed to these concentrations of prednisolone, even though they exhibited a normal ability to respond to a chemotactic stimulus. The lack of suppression of monocyte chemotaxis in patients receiving corticosteroid therapy is unexplained, but may represent a change in the circulating monocyte or lymphocyte populations.

Comparison of the antileukemic activity in vitro of dexamethasone and prednisolone in childhood acute lymphoblastic leukemia

It is generally assumed that prednisolone (PRD) and dexamethasone (DXM) have equal glucocorticoid activity of PRD is given at sevenfold higher doses. Results of clinical studies of childhood acute lymphoblastic leukemia (ALL) suggested that DXM is more potent relative to PRD than assumed. The purpose of this study was to determine the relative antileukemic activity of PRD phosphate and DXM phosphate in 133 untreated childhood ALL samples in vitro, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay. There was a marked variation in antileukemic activity of both agents among the patient samples. The median LC50 (drug concentration lethal to 50% of the ALL cells) for PRD phosphate was 3.50 microM, for DXM phosphate 0.20 microM. The individually calculated ratios of the LC50 values for PRD and DXM phosphate showed a large range from 0.7 to >500, with a median of 16.2. This 16-fold difference could not be explained by differences between these glucocorticoids in stability, hydrolysis into unesterified drug, adhesion to the wall of the microculture plates, or protein binding. ALL cells were cross-resistant to PRD and DXM phosphate (correlation coefficient = 0.85, P<0.000001). We conclude that the in vitro antileukemic activity of DXM phosphate is median 16-fold higher than that of PRD phosphate, which contrasts to the generally assumed factor of 7. Based on the higher potency of DXM, and its more favorable pharmacokinetics as reported in the literature, DXM may be preferred to PRD as the glucocorticoid in the treatment of ALL.

Clinical aspects of glucocorticoid sensitivity

Recent studies demonstrate that primary (hereditary) abnormalities in the glucocorticoid receptor gene make 6.6% of the normal population relatively "hypersensitive" to glucocorticoids, while 2.3% are relatively "resistant." These abnormalities might explain why some individuals develop severe adverse effects during low dose glucocorticoid therapy, while others do not develop side effects even during long-term therapy with a much higher dose. Awareness of this heterogeneity in glucocorticoid sensitivity in the normal population might eventually allow the prediction of a "safe" dose of glucocorticoid in individual patients. "Resistance" to the beneficial clinical effects of glucocorticoid therapy in part of the patients with severe rheumatoid arthritis and asthma is probably rarely related to generalized primary (hereditary) glucocorticoid resistance. In the majority of patients this "resistance" seems to be acquired and localized to the sites of inflammation, where it reflects high local cytokine production, which interferes with glucocorticoid action. Recognition of localized, acquired glucocorticoid resistance is of great importance indicating as alternative drug therapy with other immune-modulating drugs like cyclosporin and methotrexate. Chronic high dose glucocorticoid treatment in such patients is ineffective in alleviating symptomatology, while generalized side effects occur, reflecting the patient's normal systemic sensitivity to these drugs.

Significance of lymphoblasts in cerebrospinal fluid in newly diagnosed pediatric acute lymphoblastic malignancies with bone marrow involvement: possible benefit of dexamethasone

We analyzed retrospectively the data on 135 children treated since 1983 for acute lymphoblastic leukaemia and non-Hodgkin's lymphoma with bone marrow involvement with respect to the presence of lymphoblasts in cerebrospinal fluid (CSF) and the number of cells in CSF, both at initial diagnosis and during follow-up. Of these children 96, 11, and 28 suffered from B-progenitor, mature B cell, and T-cell malignancies respectively. In two patients initial central nervous system involvement was documented by the presence of lymphoblasts with high CSF cell counts (B+C+ patients); 19 patients had CSF lymphoblasts with normal CSF cell counts (B+C- patients); the others had no CSF blasts and normal CSF cell counts (B-C- patients). In B+C- and B-C- patients 5-year-leukaemia-free survival was 66 and 70%, respectively (i.e., not significantly different). None of the B+C- patients experienced a first relapse in the central nervous system. Differences in outcome by comparing with reports of others may be related to the use of dexamethasone instead of prednisone in almost all of our patients.

Steroid hormone receptors in three human gastric cancer cell lines

Steroid hormone receptors in three human gastric adenocarcinoma cell lines and their transplanted tumors (except nontumorigenic KATO-III) in nude mice were determined by dextran-coated charcoal assay. Progesterone receptors (PgR) were found in all cell lines, transplanted NUGC-3, and AZ 521 tumors. Estrogen receptors (ER) were found in KATO-III cells, transplanted NUGC-3, and AZ 521 tumors, whereas glucocorticoid receptors (GR) were found only in NUGC-3 tumor and no androgen receptor was found in any cell lines or transplanted tumors. Since NUGC-3 cells had ER, PgR, and GR, it was used for the study of the effects of steroid hormones on growth. The results showed the cell cycle phase distributions and growth rate of transplanted tumors were similar in hormone-treated and nontreated groups. The persistent expression of PgR in gastric cancer cell lines and tumors, and the slight increase of tumor volumes in the progesterone-treated group suggests that progesterone and its receptors may be important in the pathogenesis of gastric cancer, but their biological function remains to be elucidated.

Glucocorticoid resistance in childhood leukemia

Glucocorticoids (GC) are being used in the treatment of childhood leukemia for several decades, most successfully in newly diagnosed acute lymphoblastic leukemia (ALL). However, GC resistance is seen in 10-30% of untreated ALL patients, and is much more frequent in relapsed ALL and in acute nonlymphoblastic leukemia (ANLL). Sensitivity or resistance to GC can be measured using a cell culture drug resistance assay. For this purpose, we use the colorimetric methyl-thiazol-tetrazolium (MTT) assay. We have shown that GC resistance in childhood leukemia is related to clinical and cell biological features, and to the clinical outcome after multi-drug chemotherapy. These results are summarized in this review. In addition, we describe the apoptotic 'cell-lysis pathway' by which GC exert their antileukemic activity. This description provides a model to discuss the mechanisms of GC resistance, and to summarize the relevant literature. Possible levels of resistance relate to the diffusion of GC through the cell membrane, binding to the GC receptor (GCR), activation of the GC-GCR complex, translocation of the complex into the nucleus, binding to DNA, endonuclease-mediated DNA fragmentation, and DNA repair. A low number of GCR has been shown to be the cause of resistance in some children with ALL. However, GC resistance is likely to be caused at the post-receptor level in most leukemias. Unfortunately, there is still a lack of knowledge relating to the clinical relevance of mechanisms of GC resistance at the post-receptor level. Studies on the mechanisms of GC resistance other than those directly related to the GCR should be initiated, especially if patient material is used, as the results might indicate ways to circumvent or modulate GC resistance. A further increase in our knowledge regarding the relation between GC resistance and patient and cell biological features, the clinical relevance of GC resistance, and the mechanisms of GC resistance in leukemia patients, may contribute to further improvement in the results of GC therapy in leukemia.

Receptors for epidermal growth factor and steroid hormones in primary colorectal tumors

The presence of epidermal growth factor, estrogen, and progesterone receptors (EGFR, ER, and PR) was investigated by a competitive binding assay in 43 colorectal adenocarcinomas and 32 normal colorectal mucosa specimens. EGFR were expressed in most of the tumor specimens analyzed at levels comparable with normal mucosa. There was no correlation between EGFR and tumor localization, tumor size, tumor stage, and grading. Among tumor specimens, 13.9% and 6.9% expressed very low but detectable ER and PR levels, respectively. No statistically significant difference was found between steroid hormone receptor levels in the tumor and normal mucosa specimens, and neither was there any correlation of ER and PR with the pathological findings. Our results suggest that the EGFR system may play a role in regulating the growth of colorectal tissues. Further studies should demonstrate whether, despite the lack of correlation with histopathological parameters, EGFR expression may have a biological significance in human colorectal cancer.

Glucocorticoid receptors in human malignancies: a review

The present knowledge of the human glucocorticoid receptor (hGCR) in primary malignancies is reviewed. It is concluded that hGCR is present in a large number of these tissues; in all tissue specimens of lymphoid malignancies and in varying fractions of the different solid tumors. The hGCR functions as a hormone dependent, specific enhancer interacting protein in mediating the considerable effects of glucocorticoids on growth regulation, both through stimulation and inhibition of expression of the target genes, including other transcription regulation systems. The processes of receptor activation and regulation, as well as the effects of glucocorticoids, are tissue-specific. Subjects for future research are proposed: Establishment of more cell lines and animal models to extend investigation beyond the present concentration on only a few cell lines, especially CEM-C7, application of 'dynamic' assays to cells obtained from patients, in an attempt to predict development of glucocorticoid resistance, and further investigation of the relationships among GCR and growth factors and oncogenes.

Size and steroid-binding characterization of membrane-associated glucocorticoid receptor in S-49 lymphoma cells

The precise mechanism for glucocorticoid-mediated lymphocytolysis is not understood, although it is presumed to be receptor mediated. We have recently presented evidence that this response is mediated by a specialized form of the glucocorticoid receptor (GR) that resides in the plasma membrane (mGR). Confirmation of the previous receptor identification studies in a population of S-49 cells enriched for mGR is now made using another antibody specific for the rodent GR, BUGR-2. The membrane resident receptor could be labeled competitively with the affinity ligand dexamethasone 21-mesylate, and Scatchard analysis of whole cell binding revealed that receptor number, but not the affinity for hormone, varied between the mGR-enriched and -deficient cell populations. Steroid specificity displacement analyses showed an order of affinities as follows: triamcinolone acetonide greater than progesterone greater than dexamethasone greater than testosterone = estrogen. Studies of mGR by one- and two-dimensional gel electrophoresis, immunoblot, autoradiography, and density gradients revealed a species with an equivalent size to cytosolic receptor as well as multiple higher molecular weight species, confirming earlier studies. To offer a possible explanation for the nucleic acid origins of the mGR, RNA from the mGR-enriched cells was probed with rat GR cDNA; mGR-enriched cells contained higher levels of GR mRNA. Possible molecular etiologies of larger receptor species in membrane are discussed.

Lower incidence of meningeal leukemia when prednisone is replaced by dexamethasone in the treatment of acute lymphocytic leukemia

In 1971, Cancer and Leukemia Group B (CALGB) mounted a study of acute lymphocytic leukemia (ALL) that compared the effects of the two steroid hormones dexamethasone and prednisone. Six-hundred-forty-six children and adolescents with ALL were randomized to receive either prednisone or dexamethasone as part of their remission induction therapy. The 493 evaluable patients who achieved complete remission received the same steroid as pulses throughout remission. Specific central nervous system (CNS) therapy was randomized to either six injections of intrathecal methotrexate (IT MTX) alone or to six injections of IT MTX with cranial radiation (2,400 cGy). Both cranial radiation and dexamethasone offered increased protection against CNS relapse as the first site of failure over IT MTX alone. There were 30 CNS relapses among 238 patients (12.6%) receiving cranial radiation plus IT MTX, whereas there were 70 CNS relapses among 225 (P less than 0.001) (22.5%) in those who received IT MTX alone. Similarly, there were 33 CNS relapses among 231 (14.3%) children treated with dexamethasone, whereas there were 67 CNS relapses among 262 (25.6%) treated with prednisone (P = 0.017). Both steroids appeared equal in protecting the bone marrow. Recent national studies have shown significant improvements in preventing CNS relapse over the results in the present report. However, this finding warrants further investigation and, with further documentation, could lead to the substitution of prednisone by dexamethasone to aid further in preventing CNS relapse. This may be particularly important in patients at higher risk for CNS relapse.

Mechanisms to improve chemotherapy effectiveness

Although many effective anti-cancer agents are now available, their curative potential is compromised by a variety of problems related to tumor sensitivity, drug access, and pharmacokinetics. Central to the problem of inadequate chemotherapy is drug resistance. Drug resistance may be intrinsic, acquired, or induced, and it may develop to one drug or it may occur simultaneously to multiple agents (pleiotropic). Substantial progress has been made in our understanding of the mechanisms of drug resistance and techniques for overcoming that resistance. New evidence has emerged that highlights the importance of dose intensity in achieving successful drug treatment outcomes. Retrospective analysis of studies in breast, ovarian, colon cancer, and lymphoma suggest that new studies designed to optimize dose intensity may yield improved results. Several prospective trials have now corroborated the retrospectively derived importance of dose intensity as an independent factor in achieving improved survival. Finally, new techniques for drug delivery offer considerable promise. Chemotherapy by regional infusion and perfusion, implantable drug delivery systems, and continuous infusion of chemotherapy are unique novel techniques that may improve the efficacy of presently available chemotherapeutic agents even as new agents are developed.

Prognostic significance of glucocorticoid receptor determination in patients with chronic lymphocytic leukemia and immunocytoma--lack of a positive correlation between receptor levels and clinical responsiveness

Glucocorticoid receptors (GR) have been suggested to have prognostic significance in patients with CLL treated with chemotherapy containing glucocorticoid. In this study, the GR levels in 65 patients with advanced CLL and immunocytoma (clinical stages III and IV according to Rai) were determined by means of a whole cell assay. The median GR-level was 1,920 bs/c with a range from 0 to 9591. The patients were subsequently treated according to a prospective, randomized trial with either a combination of chlorambucil and prednisolone, or with prednimustine. No significant difference in receptor levels was found between responders (median = 1940 bs/c; n = 47) and nonresponders (median = 1950 bs/c; n = 14). To assess the influence of receptor content on prognosis we have analyzed the relationship between GR content and survival time and duration of response. There was no significant difference in duration of response and in survival between those patients with high (greater than 1920 bs/c) and those with low GR levels (less than 1920 bs/c) (log-rank test). Our data suggest that determination of GR provides no reliable indicator for clinical response to regimens with glucocorticoid as a component in patients with CLL and immunocytoma.

Levels of the 90kd heat shock protein and resistance to glucocorticoid-mediated cell killing in a range of human and murine lymphocyte cell lines

The 90kd heat shock protein is associated with the receptors for glucocorticoids and other steroids. The steroid is believed to function by releasing the receptor from hsp90 allowing the receptor to bind to DNA and activate transcription. The levels of hsp90 have been measured in a variety of lymphoid cell lines and compared with their sensitivity to steroid mediating killing. No correlation of high hsp90 levels with steroid resistance was observed. However, increased levels of hsp90 in response to steroid were observed in a number of cell lines. The significance of these findings is discussed in terms of the modulation of the cells response to steroid treatment and the mechanism of steroid resistance.

Steroid hormone receptors in human salivary gland tumours

Major salivary gland tumours were studied for the presence of hormone receptors for oestrogen and progesterone. Of the eight salivary gland tumours exhibiting varied histology, none showed high affinity receptors for oestrogen or progesterone. Salivary tissue from four patients with non-neoplastic salivary gland disease was also studied and found not to contain high affinity receptor sites. The absence of hormone receptors in these glands suggests that such tumours are not dependent on endocrine function.

Interleukin 2 synthesis in the presence of steroids: a model of steroid resistance

In this study interleukin 2 (IL-2) synthesis by human lymphocytes in the presence and absence of prednisolone in a group of normal subjects has been assessed. An association between suppression in vitro of induced phytohaemagglutinin-blastogenesis by prednisolone and synthesis of IL-2 was found. Those subjects whose lymphocytes are identified as steroid-resistant have significantly higher IL-2 activity in the supernatants of both steroid and non-steroid treated lymphocyte cultures than steroid sensitive subjects. The addition of exogenous IL-2 was found to ablate the suppressive effects of steroids on lymphocyte blastogenesis. These results suggest that significantly greater activity of IL-2 in the culture supernatants of steroid resistant subjects may represent a mechanism for glucocorticoid resistance in vitro and help explain the relationship between increased loss of grafts and steroid resistance in renal allograft recipients.

Circadian variation of cytosol glucocorticoid receptors in human polymorphonuclear leukocytes (PMN) and mononuclear cells (MN) in a normal population

Glucocorticoid cytosol and whole cell receptors from human PMN's have been quantified, and compared to those of human MN leukocytes on the same blood sample. The normal cytosol PMN receptor density (N = 15) averaged 1,254 +/- 105 (SE) molecules bound/cell at 0900 h and increased significantly to 1,497 +/- 98 at 2,100 h (P less than 0.02). MN cell cytosol receptor density was 1,198 +/- 145 at 0900 h and increased significantly to 1,551 +/- 117 molecules bound/cell at 2,100 h (P less than 0.01). Corresponding whole cell receptor densities at 0900 h were 2,845 +/- 273 (PMN) and 3,547 +/- 290 (MN) and these did not change significantly at 2,100 h.

CONCLUSIONS

Cytosol receptors in normal human PMN and MN cells increased significantly at 2,100 h from the 0900 h level while serum cortisol levels were dropping. Whole cell receptors in the same PMN and MN cell samples did not change significantly between 0900 and 2,100 h. The normal circadian variation in serum cortisol influences the distribution of the glucocorticoid receptor between the cytosol and the nucleus, but does not influence the amount of receptor available to the whole cell. This is the first time that an endogenous physiological variation of cortisol concentration has been utilized to demonstrate a corresponding change in receptor capacity in vivo.

Androgen and progesterone receptors in colonic and rectal cancers

Androgen, progesterone and estrogen receptors were analyzed in 12 primary colonic cancers and 16 primary rectal cancers. Androgen and progesterone receptors were positive in some colonic cancers and rectal carcinomas; however, none of the specimens analyzed showed estradiol receptor.

Glucocorticoid receptors and glucocorticoid resistance in human leukemia in vivo and in vitro

Clinical measurements quantitating glucocorticoid receptor sites in leukemic blasts may give useful prognostic information. In childhood ALL, where the most data is available, "high" receptor content in peripheral or marrow blasts correlated with likelihood of remission on therapy, longer durations of remission and better prognosis generally. In lymphomas and CLL as well, high receptor content correlated with likelihood of response to steroid therapy, though the number of studies is less. In AML the correlation with receptor site content is moot, and in other leukemias the reports are less complete. A model system for childhood ALL is provided by CEM cells, a glucocorticoid sensitive human cell line from a patient with the disease. These cells have glucocorticoid receptors which must be filled by hormone for greater than 24 hr for cell lysis to begin. Four types of glucocorticoid resistance have been identified thus far in clones of these cells. Their distinctive properties are described and their relevance to clinical situations briefly discussed.

Determination of glucocorticoid receptors in leukemic myeloblasts by isoelectric focusing in polyacrylamide gel

We investigated the optimal conditions for measuring glucocorticoid receptor in blast cells from patients with acute nonlymphocytic leukemia. Cytosol receptor measured with isoelectric focusing was saturated after 60 min of incubation at 0 degrees C with 100 nM of either dexamethasone or triamcinolone. Saturation was achieved when cytosol from at least 7 X 10(6) cells was used for incubation. Trypsin treatment of the cytosol resulted in a sharpened peak of receptor focusing at pH 5.6 with no loss of receptor-bound radioactivity. The two physical forms of glucocorticoid receptor were isolated with DEAE cellulose chromatography. They were both found to focus at pH 5.6 during isoelectric focusing.

Glucocorticoid receptors in human leukemias and related diseases

The evidence to date is compelling that steroid initiated cell lysis involves participation of the glucocorticoid receptor. Not only do the concentrations and specificity of hormones for cell lysis and receptor occupancy correspond, but also steroid resistant cells selected with or without prior mutagenesis often have altered receptors. The glucocorticoid receptor protein from humans and other species is a approximately 95,000 d, thiol group-containing monomer, prone to aggregation when "unactivated." After having bound steroid and been "activated," the monomeric steroid-receptor complex is altered in charge and shape so that its binding to chromatin and DNA is greatly enhanced. Simple measurement of numbers of receptor sites in cells from patients with various blood dyscrasias has given, in some disease, good correlations between high numbers of receptor sites and good therapeutic response. These correlations are strongest for childhood acute lymphoblastic leukemia (ALL) and for non Hodgkins' lymphoma. In other diseases, notably acute myelogenous leukemia, such correlations have not been found. The CEM human ALL line has been used in vitro to study mechanisms of glucocorticoid action and resistance. The requirement for "activated" steroid-receptor complex for cell lysis is shown in these cells by the spontaneous occurrence of steroid resistant, activation-labile receptor mutants. A second category of resistant cells with normal receptors has been defined. Treatment of these "lysis defective" resistant cells with compounds which result in DNA demethylation can render them steroid sensitive. Since DNA demethylation can allow formerly silent genes to become transcribed, it is possible that one or more genes specific for lysis has been "opened" in such cells. Alternatively, DNA demethylation may produce a general biochemical effect on the cell which renders it susceptible to lysis. Mutagenized CEM cells selected for steroid resistance give rise to a third class of mutants, which are deficient in receptor quantity. Each of these classes of steroid resistant cells contains information pertinent to understanding the use of glucocorticoids and the role of glucocorticoid receptors in human leukopathic disease.

The adverse effect of prolonged prednisolone pretreatment in children with acute lymphoblastic leukemia

Between 1971 and 1981, 699 children were diagnosed to have acute lymphoblastic leukemia (ALL) in Hungary. 34 of these children had received prednisolone therapy prior to the establishment of the diagnosis. The most frequent presumptive diagnoses that prompted steroid treatment were aplastic conditions and arthritic disorders. Leukemia was diagnosed when the presenting symptoms reappeared usually several weeks after the initiation of steroid therapy and often following withdrawal of the drug. Initial leukemic burden, as judged by leukocyte count and hepatosplenomegaly, was smaller in these patients than in other children with leukemia at the time of diagnosis. Although they entered remission at the same rate as the other patients, the length of continuous complete remission was significantly shorter in the prednisolone pretreated group. It appears that prolonged prednisolone therapy given before remission induction imparts a distinct unfavorable prognosis.

Estradiol and progesterone receptors in normal and pathologic colonic mucosa in humans

The presence of estradiol (E) and progesterone (Pg) receptors (R) has been demonstrated also in normal and neoplastic tissues known to be hormone-independent and in particular in primitive colonic cancer, and, possibly, in healthy colonic mucosa. In this study endoscopic and surgical colonic mucosa specimens from 55 subjects were analyzed and divided as follows: 21 samples from healthy subjects, 12 normal mucosa samples from subjects affected with colonic cancer, 8 adenomatous polyps specimens, 5 samples from ulcerative colitis drawn on areas showing macroscopic lesions and 9 colonic cancer specimens. In the control group we have observed 6 cases positive for ER (28.6%) and 2 positive for PgR (14.3%). Six normal mucosa specimens from subjects affected with colonic cancer were found to be positive for ER (50%) and 2 for PgR (16.7%). Five colonic cancers resulted ER positive (55.5%) and 4 PgR positive (44.4%). Four polyps were ER positive (50%) and 3 PgR positive (37.5%); in this group only one subject showed positive binding in the surrounding normal tissue. These data confirm the presence of ER and PgR in colonic cancer and colonic adenomas (so-called precancerous disease); in these subjects the finding of steroid receptors also in normal mucosa suggests that the presence of steroid binding could be considered as a marker of a precancerous condition.

Glucocorticoid receptors of normal and leukemic cells: role of proliferation conditions

A published whole-cell binding assay of 3H-dexamethasone (3H-DEX) was combined with cell sedimentation analysis to investigate various factors influencing specific binding of glucocorticoids by leukemic lymphoblasts. Studies with mouse L1210 and human HL-60 cell lines revealed that glucocorticoid (GC) receptors accumulate during G1 phase of the cell cycle. In human lymphoblastic leukemia, the per cell receptor number was highest in cells in S and G2 phase and lowest in small, noncycling cells. In normal human white blood cells, GC receptor content was maximal in large lymphocytes and monocytes while no receptors were present in small lymphocytes. However, the receptor density of large lymphocytes was still 3-4 fold lower than of leukemic lymphoblasts of similar size. In L1210 cells the number of GC receptors decreased considerably in stationary cultures or following inhibition of cell cycle progression by dibutyryl cyclic AMP (dbc-AMP). Receptor content was also reduced in cells growing as ascites tumors in hosts with terminal disease. Accordingly, the receptor content in leukemic blasts appeared highly dependent on cell cycle distribution and on the proliferative status of the tumor cells. These findings may in part explain the large interpatient variation and the conflicting views regarding GC receptor content and prognosis in acute lymphoblastic leukemia.

The measurement of glucocorticoid receptors in human placental cytosol

Cytosol preparations of human term placenta in Tris-HCl buffer containing dithiothreitol were incubated with [3H]dexamethasone at 4 degrees C. Under these conditions the specific binding of [3H]dexamethasone was low when compared with cytosol preparations of sheep fetal lung or ovine placenta. The inclusion of sodium molybdate in the homogenization buffer and the removal of endogenous steroids by treating the cytosol with charcoal before incubation led to a faster and increased uptake of [3H]dexamethasone by human placenta. Scatchard plot analysis of the data showed that the placenta possesses a single class of high-affinity (Kd = 13 +/- 2 nM) low-capacity (193 +/- 34 fmol/mg protein) binding sites for [3H]dexamethasone. The binding of [3H]dexamethasone was reversible and was not due to plasma contamination. The specificity of the binding sites was confirmed by competition experiments in which the highest displacement of [3H]dexamethasone from the binding sites was caused by natural and synthetic corticosteroids. These findings indicate that the human placenta at term contains specific glucocorticoid receptors in high concentrations.

Impact of treatment efficacy on the prognostic value of glucocorticoid receptor levels in childhood acute lymphoblastic leukemia

Glucocorticoid receptor (GR) levels were quantitated in leukemic blasts from bone marrow aspirates of 249 children with acute lymphoblastic leukemia (ALL) who were entered on two St. Jude Total Therapy Studies. Of these, 235 were evaluable for analysis of the relation of GR levels to clinical outcome. For the 42 patients in the earlier Total Therapy Study IX, lower GR levels (less than 16,000 sites/cell) were associated with both induction failure and more frequent relapse (p less than 0.01) [Cancer Research, Vol. 42, p. 4801 (1982)]. When patients with 'high-risk' features (leukocyte count greater than 100 X 10(3)/mm3, positive erythrocyte rosette test, central nervous system involvement, and mediastinal mass) were excluded, lower receptor levels were still associated with early and more frequent relapse (p less than 0.02). The other 193 evaluable patients were consecutively admitted to Total Therapy Study X, in which patients with 'standard-risk' or 'high-risk' features were assigned to separate protocols--XS and XH, respectively. Induction chemotherapy in both protocols consisted of prednisone, vincristine and L-asparaginase; patients in the XH protocol received additional epipodophyllotoxin (VM-26) and cytosine arabinoside twice a week for 2 weeks preceding the conventional induction therapy. To compare the prognostic value of GR level in Study X with that of Study IX (which included both 'high-risk' and 'standard-risk' patients but did not separate them into different protocol groups), children in the XH and XS protocols were analysed together. The proportion of patients with 'standard-risk' features was the same in the two studies: 69% in Study IX and 73% in Study X. In Study X, which had a significantly better treatment result (p less than 0.001), lower receptor levels were not associated with induction failure, but were correlated with more frequent relapse (p less than 0.05). When patients in XH and XS protocols were analysed separately, however, receptor levels were no longer related to treatment outcome. Thus, GR level in childhood ALL has prognostic value, but it is not an independent factor and its importance is related to the efficacy of treatment.

The relationship of blast cell glucocorticoid receptor levels to response to single-agent steroid trial and remission response in children with acute lymphoblastic leukemia

Of 263 children with glucocorticoid receptor (GR) levels measured at diagnosis of acute lymphoblastic leukemia (ALL), 27 received single-agent glucocorticoid before combination induction chemotherapy and were evaluable for in vivo clinical response to steroid. Twenty-one were glucocorticoid-responsive and 6 were resistant. There was no difference between the two groups in the distribution of age, sex, white blood cell count, immunophenotype of blasts, initial central nervous system disease or mediastinal mass. The median GR level, however, was appreciably lower in the group of patients with resistant disease (6250 vs 17,800 sites/cell, p = 0.06). Five of 12 patients with GR levels of less than 10,000 sites/cell compared to 1 of 15 with higher levels had glucocorticoid-resistant ALL (p = 0.03). All 21 patients with glucocorticoid-sensitive disease achieved a complete remission after combination induction chemotherapy, but only 3 of 5 evaluable patients in the other group did (p less than 0.04). Two patients were studied both at diagnosis and at relapse; both had decreased GR levels at relapse (below detection in one) and failed to respond to glucocorticoid. We conclude that a lower GR level is associated with glucocorticoid resistance and furthermore that a decrease in the level of GR is a mechanism of acquiring steroid resistance.

Presence and steroid inducibility of glutamine synthetase in human leukemic cells

Glutamine synthetase (EC 6.3.1.2; GS) is present in lymphoblasts from patients with acute lymphoblastic leukemia (ALL) as well as in normal peripheral blood lymphocytes. In 16 out of 20 ALL patients studied exposure of the cells to physiological concentrations of dexamethasone in vitro increased enzyme activity above the control levels. The increase was specific for glucocorticoid receptor ligands. A direct correlation was found between the magnitude of glucocorticoid-mediated increase of GS activity and the cellular levels of specific glucocorticoid receptors assayed in the same cell specimen. Moreover, the basal levels of the enzyme measured in cells prior to exposure to dexamethasone correlated negatively with receptor density. It is suggested that the presence of steroid-inducible GS in ALL cells may prove to be a marker for functional receptor sites.

Steroid receptors in breast angiosarcoma

The presence of receptors for estrogen, glucocorticoid and progesterone was determined in the cytosol of two breast angiosarcomas. Estrogen and glucocorticoid receptors were present in both of them. Progesterone receptors were present in one of the two tumors assayed. Occupied nuclear estrogen receptors have been found in the nuclear extracts of both tumors. Unoccupied nuclear receptors were found only in the progesterone-positive tumor. Density gradient analysis suggested that glucocorticoid and estrogen bindings were located predominantly in the 6S and 7 to 8S regions, whereas receptor for progesterone sedimented at 4S.