Interaction between the amino- and carboxyl-terminal regions of the rat androgen receptor modulates transcriptional activity and is influenced by nuclear receptor coactivators

Identical N-terminal deletions in the wild-type rat androgen receptor (rAR) and a constitutively active rAR (ARDelta641-902) devoid of the ligand-binding domain (LBD) resulted in dissimilar consequences in transcriptional activation: deletion of residues 149-295 abolished wild-type AR activity, but did not influence that of ARDelta641-902. The activity of the N-terminal transactivation domain is thus controlled by the hormone-occupied LBD, suggesting that the N- and C-terminal regions of rAR communicate. Consistent with this idea, a strong androgen-dependent interaction between the N-terminal region and LBD was demonstrated in a mammalian two-hybrid system using GAL4 and VP16 fusion proteins. This interaction can be direct or indirect. Several nuclear receptor coactivators (CBP, F-SRC-1, SRC-1, and RIP140) that interact with other steroid receptors were tested as potential mediators of the N- and C-terminal interaction of rAR using the mammalian two-hybrid system. CBP or F-SRC-1 not only enhanced AR-mediated transactivation, but also facilitated the androgen-dependent interaction between the N- and C-terminal domains, implying that part of the coactivator-dependent transcriptional activation occurs via this mechanism. In contrast, SRC-1, a coactivator for the progesterone receptor, inhibited both AR-mediated transactivation and interaction between the N and C termini. Recruitment of coregulators may involve AR domains other than the LBD, as F-SRC-1 and CBP enhanced, but SRC-1 repressed, the transcriptional activity of ARDelta641-902. Collectively, interplay between the N-terminal region and LBD of rAR results in the formation of a transactivation complex that includes coregulators and that is mandatory for optimal activation of androgen-induced promoters.

Newer immunosuppressive drugs: a review

In recent years, many new immunosuppressive drugs have been discovered and developed for clinical use in transplantation. This review focuses on those drugs (leflunomide, mycophenolate mofetil, sirolimus, tacrolimus) that have been shown to have immunosuppressive activity in patients. Different anti-interleukin-2 receptor antibodies are also reviewed as an example of a resurgence of development in the area of monoclonal antibodies. The price for reducing the incidence of allograft rejection by improved immunosuppression was thought to be a proportional increase in the incidence of infection and malignancy. Data from Phase III clinical trials of new immunosuppressants, however, show a statistically significant reduction in the incidence of acute rejection produced by these new drugs, which has not been accompanied by increases in infection and malignancy rates. The wide array of new drugs offers the opportunity to use combinations that block different pathways of immune activation while at the same time selecting drug combinations with nonoverlapping toxicity profiles so that doses of each single drug can be reduced below toxicity levels. The immunosuppressive therapy for patients can be tailored according to their individual needs.

Mutual transcriptional interference between RelA and androgen receptor

Cross-modulation between androgen receptor (AR) and NF-kappaB/Rel proteins was studied using various androgen- and NF-kappaB-regulated reporter genes under transient transfection conditions. In COS-1 cells, elevated expression of RelA (p65) repressed AR-mediated transactivation in a dose-dependent manner, whereas NFkappaB1 (p50), another major member of the NF-kappaB family, did not influence transactivation. The repression of AR appeared to involve the N-terminal region of the protein between residue 297 and the DNA-binding domain. RelA-mediated transrepression could not be overcome by increasing the amount of AR. Transcriptional interference between RelA and AR was mutual in that cotransfected AR was able to attenuate transactivation by RelA in a dose- and steroid-dependent fashion. An excess of RelA was able to rescue the repression to some extent. Immunological analyses of RelA and AR protein levels indicated that transrepression was not due to reciprocal decrease in their amounts. Neither did AR increase the concentration of IkappaBalpha, which can sequester and inactivate RelA. Electrophoretic mobility shift assays using extracts from cotransfected cells and purified recombinant proteins showed that AR and RelA did not significantly influence each other's DNA binding activity. Nevertheless, protein-protein interaction experiments demonstrated a weak association between AR and RelA. Collectively, these data suggest that the mutual repression in intact cells is due to formation of AR-RelA complexes that are held together by another partner or to competition for a coactivator required for transcription.

Genetic and Phenotypic Correlations Between Milk Coagulation Properties, Milk Production Traits, Somatic Cell Count, Casein Content, and pH of Milk

Genetic and phenotypic correlations between milk coagulation properties (MCP: coagulation time and curd firmness), milk yield, fat content, protein content, ln(somatic cell count) (SCS), casein content, and pH of milk and heritability of these traits were estimated from data consisting of milk samples of 4664 Finnish Ayrshire cows sired by 91 bulls. In addition, differences in average estimated breeding values (EBV) for the above traits between the cows with noncoagulating (NC) milk and those with milk that coagulated (CO samples) were examined. The estimations were carried out to study the possibilities of indirect genetic improvement of MCP by use of the above characteristics. The genetic and phenotypic correlations between MCP and the milk production traits were low or negligible. The genetic associations between desirable MCP and low SCS were rather strong (-0.45 to 0.29). Desirable MCP correlated both genetically and phenotypically with low pH of milk (-0.51 to 0.50). The rather high heritability estimates for curd firmness in different forms (0.22 to 0.39), and the wide variation in the proportion of daughters producing NC milk between the sires (0 to 47%) suggested that noncoagulation of milk is partly caused by additive genetic factors. Based on the genetic correlations between curd firmness and SCS and the high EBV for SCS obtained for the cows with NC-milk, it is possible that the loci causing noncoagulation of milk and increasing somatic cell count of milk are closely linked or partly the same. One means to genetically improve MCP and to reduce the occurrence of NC milk could thus be selection for low somatic cell count of milk.

Genetic parameters for the milk coagulation properties and prevalence of noncoagulating milk in Finnish dairy cows

The genetic parameters were estimated for milk coagulation properties and milk production traits, and the prevalence of noncoagulating milk in the Finnish dairy cattle population was investigated. Data were included for 789 Finnish Ayrshire cows and 86 Finnish Friesian cows from 51 herds. The animal model used for estimation included fixed effects for parity, stage of lactation, breed, and herd. Further, effects of milk protein genotypes on phenotypic and genetic variation in the studied traits were examined. Heritability estimates for the milk coagulation properties were moderately high. The kappa-casein B allele was associated with the best phenotypic and genetic values for curd firmness, and the A and E alleles were associated with the poorest. About 24% of the additive genetic variation in the curd firmness was due to milk protein polymorphism. About 8% of the Finnish Ayrshire cows in the present study produced noncoagulating milk. Because of the occurrence of the noncoagulating milk and a possibly unfavorable genetic trend in the milk coagulation properties, it would be important to improve these traits in the Finnish Ayrshire breed. Milk coagulation properties could be improved directly by selecting for these traits or indirectly by favoring the kappa-casein B allele or by selecting against genetic markers associated with poorly coagulating or noncoagulating milk.

Stimulation of androgen-regulated transactivation by modulators of protein phosphorylation

The effect of modulators of protein phosphorylation on the transcriptional activity of the androgen receptor (AR) was studied under transient expression conditions. Activators of protein kinase-A [8-bromo-cAMP (8-Br-cAMP)] and protein kinase-C (phorbol 12-myristate 13-acetate) or an inhibitor of protein phosphatase-1 and -2A (okadaic acid) influenced minimally pMMTV-chloramphenicol acetyl-transferase (CAT) activity in CV-1 cells cotransfected with an AR expression plasmid in the absence of androgen. In the presence of testosterone, however, all compounds enhanced AR-mediated transactivation by 2- to 4-fold. A nonsteroidal antiandrogen, Casodex, behaved as a pure antagonist; it blunted the action of testosterone and was not rendered agonistic by activators of protein kinase-A. A reporter plasmid containing two androgen response elements (AREs) in front of the thymidine kinase promoter (pARE2tk-CAT) was also used to examine promoter specificity. It was activated by 8-Br-cAMP, forskolin, or okadaic acid even without AR or androgen. However, when forskolin or okadaic acid was used together with androgen and AR, the resulting AR-dependent transactivation of pARE2tk-CAT was more than additive. Intact DNA- and ligand-binding domains, but not the N-terminal amino acid residues 40-147, of the receptor were mandatory for the synergism between protein kinase-A activators and androgen. Immunoreactive AR content in transfected COS-1 cells was not influenced by exposure to 8-Br-cAMP. Similar results were obtained by ligand binding assays. Quantitative or qualitative differences were not observed in DNA-binding characteristics between receptors extracted from cells treated with testosterone with or without protein kinase-A activator. Collectively, the synergistic stimulation of AR-dependent transactivation by androgen and protein kinase activators is not due to changes in cellular AR content or affinity of the receptor for the cognate DNA element; rather, this phenomenon seems to result from altered interaction of ligand-activated AR with other proteins in the transcription machinery.

CHEK2 variants associate with hereditary prostate cancer

Recently, variants in CHEK2 gene were shown to associate with sporadic prostate cancer in the USA. In the present study from Finland, we found that the frequency of 1100delC, a truncating variant that abrogates the kinase activity, was significantly elevated among 120 patients with hereditary prostate cancer (HPC) (four out of 120 (3.3%); odds ratio 8.24; 95% confidence interval 1.49-45.54; P=0.02) compared to 480 population controls. Suggestive evidence of segregation between the 1100delC mutation and prostate cancer was seen in all positive families. In addition, I157T variant had significantly higher frequency among HPC patients (13 out of 120 (10.8%); odds ratio 2.12; 95% confidence interval 1.06-4.27; P=0.04) than the frequency 5.4% seen in the population controls. The results suggest that CHEK2 variants are low-penetrance prostate cancer predisposition alleles that contribute significantly to familial clustering of prostate cancer at the population level.

Unifying model of driven polymer translocation

We present a Brownian dynamics model of driven polymer translocation, in which nonequilibrium memory effects arising from tension propagation (TP) along the cis side subchain are incorporated as a time-dependent friction. To solve the effective friction, we develop a finite chain length TP formalism, based on the idea suggested by Sakaue [Phys. Rev. E 76, 021803 (2007)]. We validate the model by numerical comparisons with high-accuracy molecular dynamics simulations, showing excellent agreement in a wide range of parameters. Our results show that the dynamics of driven translocation is dominated by the nonequilibrium TP along the cis side subchain. Furthermore, by solving the model for chain lengths up to 10^{10} monomers, we show that the chain lengths probed by experiments and simulations are typically orders of magnitude below the asymptotic limit. This explains both the considerable scatter in the observed scaling of translocation time with respect to chain length, and some of the shortcomings of present theories. Our study shows that for a quantitative theory of polymer translocation, explicit consideration of finite chain length effects is required.

Effect of physical training on exercise capacity and gas exchange in patients with chronic heart failure

Decreased exercise capacity is the main factor restricting the daily life of patients with chronic congestive heart failure (CHF). We performed a controlled, randomized study to evaluate the effect of dynamic exercise training of moderate intensity on exercise capacity and gas exchange in patients with CHF. Twenty-seven patients with stable CHF, New York Heart Association (NYHA) functional class II and III, were randomized to training (n = 12) and control (n = 15) groups. During a 3-month period, the training group underwent a supervised physical training program using a bicycle ergometer for 30 min 3 times a week at a load corresponding to 50 to 60% of their peak oxygen consumption. Thereafter, they were advised to continue training at home for the next 3 months. The control group did not change their previous physical activity. A graded maximal exercise test with respiratory gas analysis and an endurance test with constant submaximal workload were performed at baseline and after 3 and 6 months. The exercise endurance increased from 14.7 +/- 2.0 to 27.8 +/- 2.7 min (p < 0.01) and the peak oxygen consumption tended to improve from 19.3 +/- 1.6 to 21.7 +/- 2.3 mL/kg/min (p = 0.09) during the supervised training period. At submaximal workloads, minute ventilation was reduced by 16% per se (p < 0.01) and by 7% in proportion to carbon dioxide production (p < 0.05). Oxygen consumption at the anaerobic threshold increased from 10.5 +/- 0.8 to 12.7 +/- 1.0 mL/kg/min (p < 0.05). The positive training effects were associated with an improvement in the NYHA functional class. The effects of supervised training were preserved during the home-based training period. The results indicate that physical training of moderate intensity significantly improves the exercise capacity and reduces the exaggerated ventilatory response to exercise, particularly at submaximal working levels in patients with CHF. This is associated with alleviation of symptoms.

Influence of non-universal effects on dynamical scaling in driven polymer translocation

We study the dynamics of driven polymer translocation using both molecular dynamics (MD) simulations and a theoretical model based on the non-equilibrium tension propagation on the cis side subchain. We present theoretical and numerical evidence that the non-universal behavior observed in experiments and simulations are due to finite chain length effects that persist well beyond the relevant experimental and simulation regimes. In particular, we consider the influence of the pore-polymer interactions and show that they give a major contribution to the non-universal effects. In addition, we present comparisons between the theory and MD simulations for several quantities, showing extremely good agreement in the relevant parameter regimes. Finally, we discuss the potential limitations of the present theories.

Associations between casein haplotypes and first lactation milk production traits in Finnish Ayrshire cows

The objective of this study was to estimate the effects of beta-kappa-casein (CN) haplotypes on first-lactation milk production traits. The beta-kappa-CN haplotypes were deduced using information on beta- and kappa-CN genotypes of cows and their sires for 16,973 Finnish Ayrshire cows that had at least nine paternal half sibs. Effects of CN haplotypes on milk production traits were estimated for one haplotype at a time using an animal model, which included the fixed effects for calving year and month, age at calving, days open, beta-lactoglobulin, and a beta-kappa-CN haplotype. Differences in milk production traits were also estimated between haplotype combinations A1A+A2B and A1B+A2A within beta-kappa-CN genotype A1A2AB and between combinations A1E+A2A and A1A+A2E within genotype A1A2AE. The beta-kappa-CN haplotypes A2A and A2B were associated with high milk and protein yields and low fat content, and those that included the beta-CN A1 allele were associated with low yields and high fat content. Protein content was affected by the kappa-CN locus; haplotype A1B was associated with high protein content and A1E was with low protein content. The haplotype combination A1A+A2B was associated with 140 kg more milk yield (P = 0.045) and 0.03 percentage units less protein content (P = 0.055) than combination A1B+A2A, and combination A1A+A2E showed 0.02 percentage units greater protein content (P = 0.098) than A1E+A2A. These results indicate that genes linked to the CN loci contribute to the variation in milk yield and protein content.

Associations between milk protein polymorphism and first lactation milk production traits in Finnish Ayrshire cows

Genotypic effects of beta-casein (CN), kappa-CN, and beta-lactoglobulin (LG) on milk, fat, and protein production and fat and protein percentages were estimated for 18,686 Finnish Ayrshire cows in first lactation using an animal model. Casein genotype effects were estimated including individual beta-CN and kappa-CN simultaneously in a model and then as composite beta-kappa-CN. The A2 allele of beta-CN and the A allele of kappa-CN, as well as the A1 allele of beta-CN and the B or E allele of kappa-CN, appeared together more frequently than was expected. Because of linkage disequilibrium in the casein loci and, consequently, unbalanced data, some contradictory effects of casein genotypes were obtained with the two models. A well-founded way to estimate the effects of casein genotypes was to use beta-kappa-CN genotypes. Composite casein genotypes including the A2 allele of beta-CN were associated with the highest milk and protein production and the lowest fat content, those including the B allele of kappa-CN with the highest protein content, and those including the E allele of kappa-CN with the lowest protein content. The effect of the beta-kappa-CN genotypes on protein content was moderately strong, and the effect was somewhat smaller for other traits. The AA genotype of beta-LG had a favorable effect on milk and protein production, and the BB genotype had a favorable effect on fat content.

The therapeutic prescription for the organ transplant recipient: the linkage of immunosuppression and antimicrobial strategies

Infection and rejection, the two major barriers to successful organ transplantation, are closely linked, with immunosuppressive therapy being central to the pathogenesis of both. After almost two decades when azathioprine and prednisone, supplemented by antilymphocyte antibody therapy, were the cornerstones of post-transplant immunosuppressive programs, there has been a major increase in the therapeutic armamentarium available to treat rejection: cyclosporine, tacrolimus, mycophenolate mofetil, rapamycin, and antibodies directed against the interleukin-2 receptor. These agents are potent inhibitors of microbial specific T cell function, thus potentiating opportunistic infection with herpes group viruses, fungal and mycobacterial species, Strongyloides stercoralis, and a variety of intracellular pathogens. The mechanisms by which each of these drugs exerts its effects are an important determinant of the antimicrobial strategies that will be necessary to combat infection. Indeed, strategies to limit these infections are being linked to the nature of the immunosuppressive therapy required in a particular patient. Thus, the therapeutic prescription for the transplant patient is said to have two components: an immunosuppressive component to prevent and treat rejection, and an antimicrobial one to make it safe. In addition to using antimicrobial agents therapeutically, in the transplant patient prevention is stressed in which antibiotics are deployed prophylactically or preemptively.

Combined immunosuppression with cyclosporine (neoral) and SDZ RAD in non-human primate lung transplantation: systematic pharmacokinetic-based trials to improve efficacy and tolerability

BACKGROUND

We studied the efficacy and tolerability of combined immunosuppressive therapy with cyclosporine A microemulsion (Neoral) plus the macrolide SDZ RAD 40-0 (2-hydroxyethyl) rapamycin (RAD) in a stringent cynomolgus monkey lung graft model in comparison with cyclosporine or SDZ RAD monotherapy.

METHODS

Thirty-nine cynomolgus monkeys received mixed lymphocyte reaction (MLR) mismatched unilateral lung transplants. Immunosuppressants were administered orally as single daily doses. The observation period was 28 days and follow-up included serial trough blood drug concentrations measured by high performance liquid chromatography/mass spectrometry, blood analyses, chest radiographs, open lung biopsies, as well as tissue drug concentrations and graft histology at necropsy.

RESULTS

Graft biopsies in monkeys treated with vehicle (n=4), Neoral (day 1-7: 150 mg/kg/day; day 8-28: 100 mg/kg/day; n=6; mean +/- SE trough level (MTL): 292+/-17 ng/ml) or SDZ RAD monotherapy (1.5 mg/kg/day; n=6; MTL: 15+/-1 ng/ml) showed severe rejection. Coadministration in two transplant monkeys of Neoral (150/100 mg/kg/day) and SDZ RAD (1.5 mg/kg/day) caused their early death. In both animals, SDZ RAD blood levels were more than 5-fold higher than under monotherapy (MTL: 82+/-18 ng/ml). Simultaneous administration (n=6) of Neoral (150/100 mg/kg/day; MTL: 217+/-16 ng/ml) and SDZ RAD (0.3 mg/kg/day; MTL: 24+/-2 ng/ml) improved graft outcome (mild rejection). Side effects included renal failure (n=2) and seizures (n=1). Three monkeys survived to day 28. In this group the MTL for cyclosporin was 143+/-13 and for RAD 38+/-3. Staggered treatment completely prevented rejection in four of six grafts. However, five of six monkeys had moderate to severe diarrhea. In a concentration-controlled trial of simultaneously administered Neoral and SDZ RAD in transplant monkeys (target SDZ RAD MTL: 20-40 ng/ml; cyclosporine MTL: 100-200 ng/ml) all six monkeys survived with improved drug tolerability and an average biopsy score of mild rejection.

CONCLUSION

Combination of orally administered SDZ RAD and Neoral showed excellent immunosuppressive efficacy in a stringent lung transplant model. The drug interaction and the narrow therapeutic index of this drug combination required careful dose adjustments to optimize tolerability and efficacy.

The presence of a transcription activation function in the hormone-binding domain of androgen receptor is revealed by studies in yeast cells

To assess the importance of various regions of the androgen receptor (AR) in transcriptional regulation, we have compared its activation functions (AFs) in yeast and mammalian cells. The receptor's amino-terminal region contains a major transcriptional activator (AF-1) in both cell types, whereas AF-2 in the ligand-binding domain (LBD) is very weak in mammalian cells but clearly functional in the yeast. Hormone-binding ability of LBD is mandatory for AF-2 to operate, as illustrated by mutated LBD constructs. The activity of AF-2 in yeast is severely attenuated when the hinge region is attached to LBD, suggesting that the former region modulates AF-2 in vivo, probably by presenting an interface for interacting proteins.

A missense substitution A49T in the steroid 5-alpha-reductase gene (SRD5A2) is not associated with prostate cancer in Finland

Prostatic steroid 5-alpha-reductase gene (SRD5A2) encodes a critical enzyme involved in the conversion of testosterone to dihydrotestosterone. A germline mis-sense substitution (A49T) leads to a variant SRD5A2 protein, which has a 5-fold higher in vitro V _max than the wild-type protein (Ross et al, 1998; Makridakis et al, 1999). The A49T variant was recently associated with 2.5 to 3.28-fold increased risk of prostate cancer (PC) in African-American and Hispanic men (Makridakis et al, 1999). Also, Jaffe et al (2000) reported an association between A49T and more aggressive disease among Caucasian patients. Here, we report that the prevalence of the A49T variant in 449 Finnish PC patients was 6.0%, not significantly different from 6.3% observed in 223 patients with benign prostatic hyperplasia or 5.8% in 588 population-based controls (odds ratio for PC 1.04, 95% C.I. 0.62–1.76 P = 0.89). There was no association between A49T and the family history of the patients nor with tumour stage or grade. Our results argue against a prominent role of the A49T variant as a genetic risk factor for prostate cancer development and progression in the Finnish population. © 2001 Cancer Research Campaign www.bjcancer.com

Nordic collaborative study of the BARD1 Cys557Ser allele in 3956 patients with cancer: enrichment in familial BRCA1/BRCA2 mutation-negative breast cancer but not in other malignancies

BACKGROUND

BARD1 was originally identified as a BRCA1-interacting protein but has also been described in tumour-suppressive functions independent of BRCA1. Several studies have indicated that the BARD1 gene is a potential target for germline changes predisposing to breast and ovarian cancer. The C-terminal Cys557Ser change has previously been uncovered to associate with an increased risk of breast cancer and was recently shown to result in defective apoptotic activities.

AIM AND METHODS

Conformation-sensitive gel electrophoresis, minisequencing, TaqMan assays, denaturing high-performance liquid chromatography analysis and DNA sequencing were used to investigate the prevalence of the Cys557Ser allele in a large Nordic case-control study cohort consisting of 2906 patients with breast or ovarian cancer, 734 with prostate cancer, 188 with colorectal cancer, 128 men with breast cancer, and 3591 controls from Finland, Iceland, Denmark, Sweden and Norway.

RESULTS

The frequency of the BARD1 Cys557Ser variant seemed to increase among patients from families with breast or ovarian cancer lacking BRCA1 or BRCA2 mutations: a significant difference was obtained compared with controls (6.8% v 2.7%; p<0.001; odds ratio (OR) 2.6; 95% confidence interval (CI) 1.7 to 4.0) and with patients from BRCA1/BRCA2 mutation-positive families (6.8% v 2.2%; p = 0.01; OR 3.2; 95% CI 1.2 to 8.3). In contrast, no major association with male breast, ovarian, colorectal or prostate cancer was observed. Additionally, a novel BARD1 allele resulting in Ser558Pro was identified in familial breast cancer cases.

CONCLUSION

These results provide further evidence that BARD1 Cys557Ser confers a slightly increased risk of breast cancer in women.

High-resolution CT in long-term follow-up after lung transplantation

OBJECTIVE

Our aim was to evaluate the development of changes on high-resolution CT (HRCT) associated with chronic pulmonary rejection.

MATERIALS AND METHODS

Repeated HRCT examinations were performed 140 times on 13 consecutive lung transplant recipients during a mean observation period of 26 months. The postoperative time interval to the first detection of each chronic change on CT was calculated and compared with the onset of chronic rejection. Bronchiolitis obliterans syndrome (BOS) or the histologic diagnosis of obliterative bronchiolitis was assessed by the published criteria of the International Society for Heart and Lung Transplantation.

RESULTS

BOS developed in eight patients, on an average, within 11.6 (+/-5.0) months. Histologic diagnosis was available from five patients. On HRCT, among the first identifiable chronic changes were volume contraction, decreased peripheral vascular and bronchial markings, and thickening of septal lines, all of which appeared between 7 (+/-5.0) and 11 (+/-6.8) months postoperatively. The mean interval for appearance of bronchodilatation was 12.5 (+/-8.7) months. Hyperlucency and mosaic phenomenon were identified, on an average, 16 (+/-6.3) and 21 (+/-7.3) months after transplantation.

CONCLUSION

On radiologic monitoring of lung recipients with HRCT, in addition to bronchodilatation. a special attention should be paid to the early chronic changes, including diminution of peripheral bronchovascular markings, thickening of septal lines, and volume reduction, which usually precede the establishment of the diagnosis of chronic rejection, whereas hyperlucency and mosaic phenomenon usually appear during more advanced BOS.

Prevention of acute allograft rejection in nonhuman primate lung transplant recipients: induction with chimeric anti-interleukin-2 receptor monoclonal antibody improves the tolerability and potentiates the immunosuppressive activity of a regimen using low doses of both microemulsion cyclosporine and 40-O-(2-hydroxyethyl)-rapamycin

BACKGROUND

In previous studies of cynomolgus monkey lung allograft recipients, we demonstrated significant immunosuppressive efficacy but reduced tolerability after combined treatment with high doses of microemulsion cyclosporine (CsA) and SDZ RAD (40-O-(2-hydroxyethyl)-rapamycin). The current study was designed to compare efficacy and tolerability of a combination of low-dose CsA and high-dose SDZ RAD (CTL group) to triple therapy using the chimeric anti-interleukin-2 (IL-2) receptor (CD25) monoclonal antibody (mAb) basiliximab (anti-IL-2 receptor mAb) for induction therapy (basiliximab: 5 mg intravenously on days 0 and 4) plus low-dose CsA and low-dose SDZ RAD for maintenance immunosuppression (CD25 group). CsA and anti-IL-2 receptor mAb are drugs that reduce cytokine synthesis and block IL-2-mediated lymphocyte stimulation, respectively. SDZ RAD blocks lymphocyte stimulation by other cytokines (e.g., IL-15) that are not inhibited by anti-IL-2 receptor mAb.

METHODS

Twelve unilateral lung transplants were performed. Recipients were observed for 49 days by daily weight assessment, hemograms, blood chemistries, radiographs, and lung biopsies. Monkeys were euthanized before day 49 in the event of excessive weight loss (>25%) or organ failure. Target CsA trough levels were 100-200 ng/ml. Target SDZ RAD trough levels in the CTL group (no mAb) were 20-40 ng/ml, and 10-20 ng/ml in the CD25 group.

RESULTS

None of the monkeys in the CD25 group needed to be euthanized early due to signs of drug toxicity. In contrast, four monkeys in the CTL group were sacrificed on days 28-35 as a result of excessive weight loss (n=3) and renal functional impairment (n=1). Three recipients in the CD25 group were euthanized on days 36, 38, and 46 as a result of persistent high fever associated with severe rejection. The median animal survival in the CTL group was 32 vs. 46 days in the CD25 group (P<0.04). The only two long-term survivors in the CTL group showed moderate rejection at day 49. The median rejection scores at day 14 (A0) and day 28 (A2) were identical in the two groups, despite the fact that the mean SDZ RAD trough level was significantly lower in the CD25 group (CTL: 38+/-3 ng/ml, CD25: 18+/-2 ng/ml, P<0.0001). After basiliximab levels fell below the minimum therapeutic level (1 mg/ml) on day 28, the median rejection score at day 49 increased to A4 in the CD25 group.

CONCLUSION

This is the first study to combine an anti-IL-2 receptor mAb with a drug from the rapamycin class plus CsA. Our study shows that induction therapy with basiliximab enabled SDZ RAD blood levels to be significantly reduced, which led to improved tolerability without the penalty of increased rejection.

Capturing dynamics with Eiger, a fast-framing X-ray detector

Eiger is the next-generation single-photon-counting pixel detector following the widely used Pilatus detector. Its smaller pixel size of 75 µm × 75 µm, higher frame rate of up to 22 kHz, and practically zero dead-time (~4 µs) between exposures will further various measurement methods at synchrotron sources. In this article Eiger's suitability for X-ray photon correlation spectroscopy (XPCS) is demonstrated. By exploiting its high frame rate, complementary small-angle X-ray scattering (SAXS) and XPCS data are collected in parallel to determine both the structure factor and collective diffusion coefficient of a nano-colloid suspension. For the first time, correlation times on the submillisecond time scale are accessible with a large-area pixel detector.

Identification of germline MLH1 alterations in familial prostate cancer

Several linkage and loss of heterozygosity (LOH) analyses suggest that the region 3p21-p26, which is a chromosomal location of MLH1, could harbour a susceptibility gene for prostate cancer (PRCA). Furthermore, in a recent candidate single nucleotide polymorphism (SNP) analysis the I219V variation of the MLH1 gene was associated with PRCA. Microsatellite instability (MSI) and germ-line MLH1 mutations were originally demonstrated in hereditary non-polyposis colorectal cancer (HNPCC) but MSI and loss of MLH1 function have also been detected in PRCA. To assess the contribution of MLH1 germline mutations to the development of PRCA in Finland different approaches were used. First, the samples from 11 PRCA-colon cancer patients were screened for MLH1, MSH2 and MSH6 protein expression by immunohistochemistry (IHC). IHC revealed one patient with a putative MLH1 aberration and sequencing of this sample revealed five sequence variants including two missense variants P434L and I219V. Second, the samples from Finnish hereditary prostate cancer (HPC) families were used for the screening of MLH1 mutations which produced twelve MLH1 sequence variants including two missense mutations, I219V, as in the PRCA-colon cancer patient, and V647M. P434L and V647 were both novel, rare variants. Carrier frequencies of the I219V mutation were compared between hereditary prostate cancer (HPC) patients, unselected PRCA cases, patients with benign prostate hyperplasia and controls, but no differences between the sample groups were found. P434L was not present in this study population and V647M was a very rare variant found only in one HPC family. According to the present results, MLH1 does not have a major role in PRCA causation in Finland.

Major surgery increases serum levels of vascular endothelial growth factor only temporarily

BACKGROUND

Vascular endothelial growth factor (VEGF) is a hypoxia-induced endothelial cell-specific mitogen, which is angiogenic in vivo and up-regulated in several malignancies. VEGF can be used as a prognostic marker, but the effect of surgical trauma on serum VEGF (S-VEGF) concentrations is unknown and might reduce the value of VEGF as a serum marker.

METHODS

We monitored S-VEGF levels by enzyme-linked immunosorbent assay in patients undergoing surgery.

RESULTS

Eighteen patients with major surgery had slightly elevated S-VEGF compared with the preoperative level (median 9.5 pg/mL) on the first (median 35 pg/mL; P = 0.0002) and third (median 19 pg/mL; P = 0.004) postoperative day, but not in later samples. The levels measured in 8 patients after minor surgery did not differ from the preoperative levels (P = 0.14).

CONCLUSIONS

Even major surgery is associated only with a slight and transient increase in S-VEGF levels, and, therefore, is unlikely to interfere markedly with the use of VEGF as a prognostic marker.

Heterodimerization is mainly responsible for the dominant negative activity of amino-terminally truncated rat androgen receptor forms

Rat androgen receptor (rAR) mutants devoid of the amino-terminal transactivation domain are able to behave as dominant negative regulators of wild-type rAR. To address the underlying mechanisms of the trans-dominant negative action, we have examined the roles of the DNA-binding domain (DBD) and the ligand-binding domain (LBD) in this process. Transactivation experiments in CV-1 cells complemented by electrophoretic mobility shift assays revealed that the dominant negative receptor forms repress the function of wild-type rAR mainly through heterodimer formation, rather than through competition for binding to cognate DNA elements. Heterodimerization of receptor forms containing LBDs may take place even in the absence of specific DNA binding.