Blockade of Hsp90 by 17AAG antagonizes MDMX and synergizes with Nutlin to induce p53-mediated apoptosis in solid tumors

Strategies to induce p53 activation in wtp53-retaining tumors carry high potential in cancer therapy. Nutlin, a potent highly selective MDM2 inhibitor, induces non-genotoxic p53 activation. Although Nutlin shows promise in promoting cell death in hematopoietic malignancies, a major roadblock is that most solid cancers do not undergo apoptosis but merely reversible growth arrest. p53 inhibition by unopposed MDMX is one major cause for apoptosis resistance to Nutlin. The Hsp90 chaperone is ubiquitously activated in cancer cells and supports oncogenic survival pathways, many of which antagonize p53. The Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17AAG) is known to induce p53-dependent apoptosis. We show here that in multiple difficult-to-kill solid tumor cells 17AAG modulates several critical components that synergize with Nutlin-activated p53 signaling to convert Nutlin's transient cytostatic response into a cytotoxic killing response in vitro and in xenografts. Combined with Nutlin, 17AAG destabilizes MDMX, reduces MDM2, induces PUMA and inhibits oncogenic survival pathways, such as PI3K/AKT, which counteract p53 signaling at multiple levels. Mechanistically, 17AAG interferes with the repressive MDMX-p53 axis by inducing robust MDMX degradation, thereby markedly increasing p53 transcription compared with Nutlin alone. To our knowledge Nutlin+17AAG represents the first effective pharmacologic knockdown of MDMX. Our study identifies 17AAG as a promising synthetic lethal partner for a more efficient Nutlin-based therapy.

Effects of risedronate on bone marrow adipocytes in postmenopausal women

SUMMARY

Aminobisphosphonates promote osteoblastogenesis while inhibiting adipogenesis in vitro. Their effect on adipogenesis in vivo remains unknown. In this study, we demonstrate that risedronate prevents marrow fat infiltration in postmenopausal women after 3 years of treatment.

INTRODUCTION

Age-related bone loss is associated with high levels of adipogenesis within the bone marrow at the expense of osteoblast population. Bisphosphonates stimulate osteoblastogenesis while inhibiting adipogenesis in vitro. In the present study, we tested whether the effect of bisphosphonates on marrow adipogenesis in vitro is also seen in vivo.

METHODS

We analyzed transiliac bone biopsies from a randomized, placebo-controlled clinical trial that evaluated the effects of risedronate treatment 5 mg/day on vertebral and non-vertebral fractures in women with postmenopausal osteoporosis. Paired bone biopsies were obtained from a subset of patients at baseline and after treatment with placebo or risedronate for 3 years (n = 14 per group). Biopsies were stained with toluidine blue and hematoxylin/eosin. Adipocyte volume/tissue volume (AV/TV), mean adipocyte number (AD(#)), and mean adipocyte diameter (AD(diam)) were quantified. Finally, expression levels of the adipogenesis transcription factor peroxisome proliferator activator gamma 2 (PPARγ2) within the bone marrow were quantified using immunohistochemistry.

RESULTS

In the placebo group, AV/TV, AD(#), and AD(diam) significantly increased after 3 years (~15%, p < 0.01). In contrast, AD(diam) remained unchanged and AV/TV and AD(#) were significantly reduced (~20%) in the risedronate group at 3 years (p < 0.01). These changes were associated with a significant reduction in PPARγ2 expression in the bone marrow of risedronate-treated women.

CONCLUSIONS

Risedronate reduces bone marrow fat in postmenopausal women. These findings are the first demonstration of an effect of bisphosphonates on marrow fat in humans in vivo. By regulating the amount of fat within the bone marrow, this effect may contribute to the beneficial effect of bisphosphonates on bone mass.

The correlation between the oral glucose tolerance test 30-minutes plasma glucose and risk factors for diabetes and cardiovascular diseases: a cross-sectional epidemiological study of diabetes in Fujian Province in the South-East of China

OBJECTIVE

To investigate the correlation between abnormal oral glucose tolerance test (OGTT) 30-min plasma glucose (PG) and risk factors and metabolic abnormalities of diabetes and cardiovascular diseases (CVD).

METHODS

Participants (no.=2457) underwent a physical examination, blood biochemistry examination, OGTT, and a 12-lead electrocardiogram. We measured fasting PG (FPG) and PG at 30 min (30minPG) and 1 h (1hPG) of the OGTT. The association between an increase in 30minPG (by 1 SD) and the metabolic abnormalities of diabetes and CVD such as hypertension, overweight and obesity, central obesity, and hyperlipidemia; osteoporosis was assessed by logistic regression analysis after controlling for FPG and 2hPG.

RESULTS

This analysis showed that an increase of 30minPG by 1 SD (1.92 mmol/l) significantly increased the risk of chronic metabolic abnormalities in diabetes and CVD such as hypertension, overweight, and obesity, central obesity, hyperlipidemia, and osteoporosis. Stepwise multiple regression analysis also showed that 30minPG was significantly correlated with male gender, smoking, FPG, 2hPG, total cholesterol, waist/hip ratio, and blood pressure.

CONCLUSIONS

An elevation of 30minPG increased the risk of diabetes and CVD. The increased risk was independent of FPG, 2hPG, age, sex, and smoking status.

Tunneling Effects and Electrical Conductivity of CNT Polymer Composites

A three-dimensional (3D) carbon nanotube (CNT) network computational model was developed to investigate the electrical conductivity and current flow in polymer composites with randomly dispersed CNTs. A search algorithm was developed to determine conductive paths for 3D CNT arrangements and to account for electron tunneling effects. Tunneled currents were obtained as a function of tunneling distance and matrix material. Several possible CNT conductive paths were obtained and finite-element representative volume elements (RVEs) were then used to predict current densities in different CNT arrangements. The predictions indicate that random CNT arrangements can be optimized for current transport.

Vascular endothelium changes after conditioning in hematopoietic stem cell transplantation: role of cyclophosphamide and busulfan

Vascular endothelial injury, a feature of some complications of hematopoietic stem cell transplantation (HSCT), is characterized by increased endothelial cells. We investigated that classical pretreatment drugs in HSCT could result in vascular endothelial injury in mice. Six-to eight-week-old female BALB/c mice were divided into a control group, a cyclophosphamide group (60 mg/kg per day for 2 days) and a busulfan group (4 mg/kg per day for 4 days). We observed the general state of health and regularly counted the number of white blood cells. Circulating endothelial cells and their progenitors were estimated by flow cytometry. Morphologic endothelial changes were analyzed with optical and transmission electron microscopy. After conditioning with cyclophosphamide or busulfan, white blood cells fell to a low number with injuries noted on hematoxylin and eosin-stained pathology sections. Circulating endothelial cells and their progenitors peaked significantly higher than in the control group. Vascular endothelial injuries were observed in the 2 experimental groups by transmission electron microscopy. These data support the hypothesis the vascular endothelial injury occurs during conditioning with cyclophosphamide or busulfan for HSCT, with simultaneous mobilization of endothelial progenitor cells.

Mapping quantitative trait loci using the MCMC procedure in SAS

The MCMC procedure in SAS (called PROC MCMC) is particularly designed for Bayesian analysis using the Markov chain Monte Carlo (MCMC) algorithm. The program is sufficiently general to handle very complicated statistical models and arbitrary prior distributions. This study introduces the SAS/MCMC procedure and demonstrates the application of the program to quantitative trait locus (QTL) mapping. A real life QTL mapping experiment in wheat female fertility trait was used as an example for the demonstration. The fertility trait phenotypes were described under three different models: (1) the Poisson model, (2) the Bernoulli model and (3) the zero-truncated Poisson model. One QTL was identified on the second chromosome. This QTL appears to control the switch of seed-producing ability of female plants but does not affect the number of seeds produced once the switch is turned on.

hSSB1 binds and protects p21 from ubiquitin-mediated degradation and positively correlates with p21 in human hepatocellular carcinomas

Downregulation of hSSB1, a single-stranded DNA-binding protein, causes increased radiosensitivity, defective checkpoint activation and genomic instability. However, the mechanisms of hSSB1 function in these responses remain to be uncovered. Here, we present evidence that hSSB1 directly binds p21 and this interaction may prevent p21 from ubiquitin-mediated degradation. Furthermore, both promotion of the G1/S transition and abrogation of the G2/M checkpoints induced by hSSB1 knockdown are partially dependent on p21. Most importantly, hSSB1 and p21 levels are positively correlated in human hepatocellular carcinomas (HCC), as determined by immunostaining. Therefore, hSSB1 may positively modulate p21 to regulate cell cycle progression and DNA damage response, implicating hSSB1 as a novel, promising therapeutic target for cancers such as HCC.

Edaravone alleviates delayed neuronal death and long-dated cognitive dysfunction of hippocampus after transient focal ischemia in Wistar rat brains

Edaravone is currently being used in acute ischemic stroke both in clinical and experimental research as a potent antioxidant. Here we explore the effects of edaravone on delayed neuronal death (DND) and long-dated cognitive dysfunction of hippocampus after cerebral ischemia-reperfusion (IR) injury and explain the underlying mechanisms and pathways. Our findings suggested that edaravone not only significantly alleviated delayed neuronal death and cognitive dysfunction of hippocampus after cerebral focal ischemia, but also markedly decreased malondialdehyde (MDA) levels. In addition, edaravone increased superoxide dismutase (SOD) levels and reduced the levels of inflammatory cytokines such as IL-1β and TNF-α expression; edaravone, also suppressed glial fibrillary acidic protein (GFAP) proliferation at days 3, 7 and 30 after reperfusion. Overall, the consensus emerging from this body of data indicated that edaravone exerts a later neuroprotective effect to hippocampus through its ability to inhibit inflammation, suppression of astrocyte activation and scavenging free radicals in stroke events.

Abstract P5-01-12: Specific Tumor Component Spectrum as a Predictor of Response to Neoadjuvant Chemotherapy in Breast Cancer

BACKGROUND: Monitoring individual tumor response to neoadjuvant chemotherapy could provide surrogate markers for oncologists to adjust therapeutics in order to minimize collateral damage from ineffective therapies. Diffuse optical spectroscopy imaging (DOSI), by increasing the wavelength range and resolution, has been employed to characterize malignant tumor and its response to neoadjuvant chemotherapy since it measures the abundance in the four major chromophores (lipid, oxy-hemoglobin, deoxy-hemoglobin and water). Through the application of a spectral analysis method, Self-Referencing Differential Spectroscopy (SRDS) analysis, which accounts for only intersubject variability, a novel optical intrinsic biomarker which is unique to cancer was revealed. By fitting the difference spectrum between tumor and normal tissues to the four component basis spectra, the residuals disclose a spectral fingerprint called specific tumor component (STC) spectrum which contains specific absorption bands which separate normal from abnormal tissue and benign from malignant tumors.

PATIENTS AND METHODS: 14 patients were enrolled in this study and all the subjects provided informed written consent according to an institution-approved protocol. Measurements were taken pre-, post-neoajuvant chemotherapy and the midpoint in the treatment. The chemotherapy regimen is 2-4 cycles of doxorubicin-cyclophosphamide (A/C), followed by 2-4 cycles of carboplatin-taxol/abraxane-avastin (nabTC). Tumor classification was confirmed by pathology reports and 8 out of 14 patients were classified as complete responders (CR); the rest as noneresponders (NR). Pre and post-treatment STC spectra were compared in different pathological responding categories. Data were analyzed by using custom software designed for Matlab. The concentrations of NIR absorbers will be calculated from a spectral model of tissue absorption by using the basis spectra. For the SRDS method, the absorption spectra will be further analyzed by using custom software (Elantest; Laboratory for Fluorescence Dynamics, Irvine, Calif, www.lfd.edu). Details of SRDS method has been described previously.

RESULTS: The shape of STC spectra for non-responders was well preserved since insusceptible tumor structure will remain basically unaffected during the chemotherapy. Whereas in the completed responders, the therapy-induced changes in tumor microvasculature, edema, and necrosis lead to a significant dissimilarity in STC spectra.

CONCLUSION: STC spectrum, as an endogenous in vivo biomarker, can predict pathological response in breast tumors treated with neoadjuvant chemotherapy.

Integrated biomarker response index for the assessment of environmental stress of the Yangtze River (Nanjing section)

In the present study, multibiomarker effects of the river water of three representative sections in Nanjing section of the Yangtze River were investigated in goldfish (Carassius auratus). The organic toxicants were extracted from the water samples using solid phase extraction. Acetylcholinesterase (AChE), glutathione-S-transferase (GST), 7-ethoxyresorufin-O-deethylase (EROD), glutathione peroxidase (GPx) and Na+/K+-ATPase activities were determined after exposure of the extracted components. The fractions of water samples from three sections (Daqiao, Sanchahe and Jiangxinzhou) altered these enzymatic activities. With the change of the extracts polarity, the levels of AChE, GST, EROD, Na+/K+-ATPase activities were different. The responses of enzymatic activities were mostly significant for those exposures of intermediate polar components (50-80% methanol extracts) and weakly polar components (ether and ether/hexane extracts). It has been shown that toxicants were mainly concentrated in these fractions in the Yangtze River (Nanjing section). With regard to response for different sections, EROD and GST activities seem to be more sensitive biomarkers. Integrated biomarker response index (IBR) were calculated and used to evaluate an integrated impact of pollutants from different sampling sections. The order of negative biological effects of the three sections was Jiangxinzhou>Sanchahe>Daqiao. The wild fish living in Nanjing section of the Yangtze River were at potential ecological risk.

Part 5. Public health and air pollution in Asia (PAPA): a combined analysis of four studies of air pollution and mortality

BACKGROUND

In recent years, Asia has experienced rapid economic growth and a deteriorating environment caused by the increasing use of fossil fuels. Although the deleterious effects of air pollution from fossil-fuel combustion have been demonstrated in many Western nations, few comparable studies have been conducted in Asia. Time-series studies of daily mortality in Asian cities can contribute important new information to the existing body of knowledge about air pollution and health. Not only can these studies verify important health effects of air pollution in local regions in Asia, they can also help determine the relevance of existing air pollution studies to mortality and morbidity for policymaking and environmental controls. In addition, the studies can help identify factors that might modify associations between air pollution and health effects in various populations and environmental conditions. Collaborative multicity studies in Asia-especially when designed, conducted, and analyzed using a common protocol-will provide more robust air pollution effect estimates for the region as well as relevant, supportable estimates of local adverse health effects needed by environmental and public-health policymakers.

SPECIFIC OBJECTIVES

The Public Health and Air Pollution in Asia (PAPA*) project, sponsored by the Health Effects Institute, consisted of four studies designed to assess the effects of air pollution on mortality in four large Asian cities, namely Bangkok, in Thailand, and Hong Kong, Shanghai, and Wuhan, in China. In the PAPA project, a Common Protocol was developed based on methods developed and tested in NMMAPS, APHEA, and time-series studies in the literature to help ensure that the four studies could be compared with each other and with previous studies by following an established protocol. The Common Protocol (found at the end of this volume) is a set of prescriptive instructions developed for the studies and used by the investigators in each city. It is flexible enough to allow for adjustments in methods to optimize the fit of health-effects models to each city's data set. It provides the basis for generating reproducible results in each city and for meta-estimates from combined data. By establishing a common methodology, factors that might influence the differences in results from previous studies can more easily be explored. Administrative support was provided to ensure that the highest quality data were used in the analysis. It is anticipated that the PAPA results will contribute to the international scientific discussion of how to conduct and interpret time-series studies of air pollution and will stimulate the development of high-quality routine systems for recording daily deaths and hospital admissions for time-series analysis.

METHODS

Mortality data were retrieved from routine databases with underlying causes of death coded using the World Health Organization (WHO) International Classification of Diseases, 9th revision or 10th revision (ICD-9, ICD-10). Air quality measurements included nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter with aerodynamic diameter < or = 10 microm (PM10), and ozone (O3) and were obtained from several fixed-site air monitoring stations that were located throughout the metropolitan areas of the four cities and that met the standards of procedures for quality assurance and quality control carried out by local government units in each city. Using the Common Protocol, an optimized core model was established for each city to assess the effects of each of the four air pollutants on daily mortality using generalized linear modeling with adjustments for time trend, seasonality, and other time-varying covariates by means of a natural-spline smoothing function. The models were adjusted to suit local situations by correcting for influenza activity, autocorrelation, and special weather conditions. Researchers in Hong Kong, for example, used influenza activity based on frequency of respiratory mortality; researchers in Hong Kong and Shanghai used autoregressive terms for daily outcomes at lag days; and researchers in Wuhan used additional smoothing for periods with extreme weather conditions.

RESULTS AND DISCUSSION

For mortality due to all natural (nonaccidental) causes at all ages, the effects of air pollutants per 10-microg/m3 increase in concentration was found to be higher in Bangkok than in the three Chinese cities, with the exception of the effect of NO2 in Wuhan. The magnitude of the effects for cardiovascular and respiratory mortality were generally higher than for all natural mortality at all ages. In addition, the effects associated with PM10 and O3 in all natural, cardiovascular; and respiratory mortality were found to be higher in Bangkok than in the three Chinese cities. The explanation for these three findings might be related to consistently higher daily mean temperatures in Bangkok, variations in average time spent outdoors by the susceptible populations, and the fact that less air conditioning is available and used in Bangkok than in the other cities. However, when pollutant concentrations were incorporated into the excess risk estimates through the use of interquartile range (IQR), the excess risk was more comparable across the four cities. We found that the increases in effects among older age groups were greater in Bangkok than in the other three cities. After excluding data on extremely high concentrations of PM10 in Bangkok, the effect estimate associated with PM10 concentrations decreased in Bangkok (suggesting a convex relationship between risk and PM10, where risk levels off at high concentrations) instead of increasing, as it did in the other cities. This leveling off of effect estimates at high concentrations might be related to differences in vulnerability and exposure of the population to air pollution as well as to the sources of the air pollutant. IMPLICATIONS OF THE STUDY: The PAPA project is the first coordinated Asian multicity air pollution study ever published; this signifies the beginning of an era of cooperation and collaboration in Asia, with the development of a common protocol for coordination, data management, and analysis. The results of the study demonstrated that air pollution in Asia is a significant public health burden, especially given the high concentrations of pollutants and high-density populations in major cities. When compared with the effect estimates reported in the research literature of North America and Western Europe, the study's effect estimates for PM10 were generally similar and the effect estimates for gaseous pollutants were relatively higher. In Bangkok, however, a tropical city where total exposures to outdoor pollution might be higher than in most other cities, the observed effects were greater than those reported in the previous (i.e., Western) studies. In general, the results suggested that, even though social and environmental conditions across Asia might vary, it is still generally appropriate to apply to Asia the effect estimates for other health outcomes from previous studies in the West. The results also strongly support the adoption of the global air quality guidelines recently announced by WHO.

Associations between the genetic polymorphisms of MTHFR and outcomes of methotrexate treatment in rheumatoid arthritis

OBJECTIVES

To determine whether 5, 10-methylenetetrahydrofolate reductase (MTHFR) rs1801133C/T, rs1801131A/C, rs2274976A/G, rs2066462C/T genetic polymorphisms are associated with clinical response and adverse effects (AEs) of methotrexate (MTX) treatment in Chinese Han patients with rheumatoid arthritis (RA).

METHODS

One hundred and ten RA patients defined by the American College of Rheumatology (ACR) 1987 revised criteria were involved in this study. All patients were treated with low-dose MTX (10-15 mg/week) without concomitant uses of other DMARDs. Clinical response (using ACR20 criteria) and AEs were evaluated at 0, 4, 12, 16 and 24 weeks. The genotypes of MTHFR rs1801133C/T, rs1801131A/C, rs2274976A/G and rs2066462C/T were detected by real-time fluorescent quantitative PCR.

RESULTS

The allele frequency of rs1801131C in the clinical response group was higher than in the non-response group (21.0% vs. 8.1%, p<0.05), and the patients with CC or AC genotype had greater clinical response than those with AA genotype. The allele frequencies of rs1801133T and rs2274976A were higher in the group with AEs than that without AEs (56.4% vs. 37.5% and 14.9% vs. 4.2%, respectively, both p<0.05). The patients with CT or TT genotype in rs1801133 had higher risks of AEs than those with CC genotype.

CONCLUSIONS

While rs1801131A/C genetic polymorphism is associated with the clinical response, rs1801133C/T and rs2274976A/G genetic polymorphisms are associated with MTX-related AEs in the treatment of RA. This suggests individualisation is necessary to achieve optimal outcomes in MTX therapy of RA.

Dexamethasone synergizes with lenalidomide to inhibit multiple myeloma tumor growth, but reduces lenalidomide-induced immunomodulation of T and NK cell function

To determine the effect of dexamethasone on the antimyeloma effects of lenalidomide, we tested in vitro proliferation, tumor suppressor gene expression, caspase activity, cell cycling, and apoptosis levels in a series of multiple myeloma (MM) and plasma cell leukemia cell lines treated with lenalidomide and dexamethasone, alone or in combination. The effect of dexamethasone on the immunomodulatory activities of lenalidomide such as T cell and natural killer (NK) cell activation was measured via interleukin [IL]-2 production, and interferon-gamma and granzyme B production respectively. Lenalidomide inhibited proliferation in most cell lines tested, and this effect was enhanced by dexamethasone. This effect was observed in MM cells containing the high-risk cytogenetic abnormalities t(4;14), t(14;16), del17p, del13, and hypodiploidy. Mechanistically, lenalidomide plus dexamethasone synergistically induced expression of the tumor suppressor genes Egr1, Egr2, Egr3, p15, p21, and p27 in MM cell lines and MM patient cells. The combination activated caspases 3, 8, and 9; and induced cell cycle arrest and apoptosis. Lenalidomide alone increased T cell production of IL-2, and NK cell production of interferon-gamma and granzyme B. Notably, dexamethasone antagonized these immunostimulatory effects of lenalidomide in a dose-dependent manner. These data further elucidate the mechanism of action of lenalidomide and dexamethasone in MM, and suggest that use of low-dose dexamethasone with lenalidomide may retain the antiproliferative effect of lenalidomide while permitting greater immunomodulatory effects of this combination regimen.