Net primary productivity of China's terrestrial ecosystems from a process model driven by remote sensing

The terrestrial carbon cycle is one of the foci in global climate change research. Simulating net primary productivity (NPP) of terrestrial ecosystems is important for carbon cycle research. In this study, China's terrestrial NPP was simulated using the Boreal Ecosystem Productivity Simulator (BEPS), a carbon-water coupled process model based on remote sensing inputs. For these purposes, a national-wide database (including leaf area index, land cover, meteorology, vegetation and soil) at a 1 km resolution and a validation database were established. Using these databases and BEPS, daily maps of NPP for the entire China's landmass in 2001 were produced, and gross primary productivity (GPP) and autotrophic respiration (RA) were estimated. Using the simulated results, we explore temporal-spatial patterns of China's terrestrial NPP and the mechanisms of its responses to various environmental factors. The total NPP and mean NPP of China's landmass were 2.235 GtC and 235.2 gCm(-2)yr(-1), respectively; the total GPP and mean GPP were 4.418 GtC and 465 gCm(-2)yr(-1); and the total RA and mean RA were 2.227 GtC and 234 gCm(-2)yr(-1), respectively. On average, NPP was 50.6% of GPP. In addition, statistical analysis of NPP of different land cover types was conducted, and spatiotemporal patterns of NPP were investigated. The response of NPP to changes in some key factors such as LAI, precipitation, temperature, solar radiation, VPD and AWC are evaluated and discussed.

Brain damage following severe acute normovolemic hemodilution in combination with controlled hypotension in rats

BACKGROUND AND AIM

The reduced oxygen content and perfusion pressure during acute normovolemic hemodilution (ANH) and controlled hypotension (CH) raise concerns about hypoperfusion and ischemic injury to the brain. In this study on rats, we examined the brain damage following four different degrees of ANH combined with CH.

METHODS

Forty rats were randomly assigned to receive a sham operation or CH and ANH [with a hematocrit (Hct) of 30, 25, 20 or 15%]. ANH was performed after baseline physiological parameters had been monitored for 20 min; 30 min later, CH was induced using sodium nitroprusside, and the mean arterial blood pressure was maintained at 50-60 mmHg for 1 h. Rats were killed 3.5 h after hemodilution. Ultrastructural alterations in the CA1 region of the rat hippocampus were observed, and serum concentrations of S100B and neuron-specific enolase (NSE) were measured before and after ANH.

RESULTS

The serum S100B concentration increased significantly in the Hct 20% + CH and Hct 15% + CH groups. However, there were no significant differences in the serum levels of NSE between the groups. In the CA1 region of the rat hippocampus, marked ultrastructural alterations, such as mitochondrial denaturalization and nucleus distortion, were observed in the Hct 20% + CH and Hct 15% + CH groups.

CONCLUSION

Severe ANH (Hct < or = 20%) combined with CH may induce cerebral damage, as confirmed by marked ultrastructural alterations in the CA1 region of the rat hippocampus and significantly increased serum levels of S100B, and should be avoided.

Controlled release of insulin from PLGA nanoparticles embedded within PVA hydrogels

A simple and versatile delivery platform for peptide and protein based on physically cross-linked poly (vinyl alcohol) (PVA) hydrogels containing insulin-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles was successfully fabricated. The particle morphology and size were characterized by SEM and laser light scattering method, respectively. Results showed that these particles had a mean diameter of 615 nm with a narrow size distribution and homogeneous particle production. The protein encapsulation efficiency was 72.6%. When insulin-loaded PLGA nanoparticles were administered intraperitoneally as a single dose (20 U/kg) to streptozotocin-induced diabetic mouse, blood glucose levels of these mice decreased and it could be sustained at such levels over 24 h. In vitro release further indicated that entrapment of the nanoparticles into the PVA hydrogels causes a reduction in both the release rate and the total amount of insulin released, which suggesting that PLGA nanoparticles entrapped into the PVA hydrogels showed more suitable controlled release kinetics for protein delivery.

Correlation between angiotensinogen gene polymorphisms and essential hypertension in Chinese population

Essential hypertension (EHT) has a genetic basis. Considering the pathological, physiological and biological mechanisms implicated in blood pressure regulation, many candidates have been listed as hypertension genes, of which the angiotensinogen gene (AGT) is weighed as the most promising one.

Evidence of immune tolerance to blood group antigens in a case of ABO-incompatible pediatric liver transplantation

In a 12-year-old patient with blood group O, who had received a partial liver graft 10 years ago from his father with blood group A, the levels of anti-A-specific antibodies (Abs) were persistently undetectable after the transplantation, while the levels of anti-B-specific Abs gradually increased and attained a plateau. Peripheral blood mononuclear cells (PBMCs) from this patient were engrafted into NOD/SCID mouse in order to investigate the immune response to donor-type blood group antigens. Even after sensitization with blood group-A erythrocytes, no anti-A Abs were detected in the serum samples of the mouse that received PBMCs from the blood group-O recipient of group-A liver allograft, however, immunoglobulins specific for antigens other than the A antigens were produced. Thus, we provide a possible evidence of immune tolerance to blood group antigens in this ABO-incompatible pediatric liver transplantation.

Selective hepatic vascular exclusion and Pringle maneuver: a comparative study in liver resection

OBJECTIVE

Most liver resections require champing of the hepatic pedicle (Pringle maneuver) to avoid excessive blood loss. But Pringle maneuver cannot control backflow bleeding of the hepatic vein. Resection of liver tumors involving hepatic veins may cause massive hemorrhage or air embolism from injuries of the hepatic vein. Although total hepatic vascular exclusion (THVE) can prevent bleeding of the hepatic vein effectively, it also may result in systemic hemodynamic disturbance because of the clamped inferior vena cava (IVC). SHVE, a new technique, can control the inflow and outflow of the liver without clamping the vena cava. We compared the effects of selective hepatic vascular exclusion (SHVE) and Pringle maneuver in resection of liver tumors involving the junction of the hepatic vein.

METHODS

From January 2000 to October 2005, 2100 patients with liver tumors had undergone liver resections in our department. Among them, tumors of 235 cases adhered to or were close to the junction of one or more hepatic veins. Both SHVE and Pringle maneuver were used to control blood loss during hepatectomy. These 235 cases were divided into two groups: Pringle maneuver group (110) from January 2000 to December 2002 and SHVE group (125) from January 2003 to October 2005. Data were analyzed regarding the intraoperative and postoperative courses of the patients. In the SHVE group, total SHVE (clamping the porta hepatis and all major hepatic veins) was used in 69 cases and partial SHVE (clamping the porta hepatic and one or two hepatic veins) in 56 cases. There were three methods in hepatic veins occlusion: ligating with suture, encircling and occluding with tourniquets and clamping with Satinsky clamps.

RESULTS

There was no difference between the two groups regarding the age, gender, tumor size, cirrhosis and HBsAg rate, ischemia time and operating time. Intraoperative blood loss and transfusion requirements were significantly decreased in the SHVE group. Hepatic veins rupture with massive blood loss occurred in 14 and air embolism in three during the tumor resection, but there was no massive blood loss and air embolism in the SHVE group due to hepatic vein occlusion. Postoperative bleeding, reoperation, liver failure and mortality rate were higher, and ICU stay and hospital stay were longer in the Pringle group than those in the SHVE group.

CONCLUSION

SHVE is much more effective than Pringle maneuver in controlling intraoperative bleeding. It can prevent massive blood loss and air embolism from hepatic veins rupture and can reduce the postoperative complication rate and mortality rate. Clamping the hepatic veins with Satinsky clamps is much safer and easier than ligating with suture and occluding with tourniquets.

Matrix metalloproteinase 2 (MMP2) polymorphism, Helicobacter pylori (HP) infection and esophageal adenocarcinoma (EA) risk

10553

Background: Epidemiologic studies suggest that HP infection protects against EA risk, as HP-mediated chronic atrophic gastritis reduces acid reflux. Genetic variations may modify the host response to HP infection and alter this risk. MMP2 expression is commonly upregulated in HP infections. We hypothesize that a functional MMP2 promoter polymorphism (-C1306T) that abolishes a Sp1 binding site and decreases promoter activity will also reduce the protective effects of HP infections in EA risk. Methods: HP status was determined in 98 EA patients and 101 age and gender matched healthy controls, using a commercially available serum immunoblotting kit (Helicoblot 2.1, Genelabs Diagnostics) that measures ever, current, CagA+ and VacA+ HP infections. Genotyping was performed using TaqMan. Data were analyzed using unconditional logistic regression. Results: 39% of cases and 44% of controls (P=0.69) had MMP2 variants (T/T or C/T). 36% of cases and 42% of controls were ever HP infected (P= 0.35). In individuals carrying the MMP2 wild type (CC) genotype, ever HP infection was strongly protective against EA [Odds Ratio (OR) 0.32: 95% CI, 0.13–0.75; P=0.008]. In contrast, in individuals carrying the MMP2 variants that are associated with lower promoter activity, this protective effect was lost (OR 1.76; 95% CI, 0.06–5.2; P= 0.30). Similar results were found when evaluating the MMP2 and current, CagA or VacA infection. Statistical interactions between MMP2 genotype and ever HP infection (P=0.027) and between MMP2 genotype and VacA+ infection (P= 0.035) were significant. Conclusions: We are the first to report that host factors such as the MMP2 polymorphism modulate the role of HP infection in EA susceptibility.

No significant financial relationships to disclose.

Stage and histology influence the relationship between MDM2 promoter polymorphism and esophageal cancer and overall survival (OS)

21047

Background: A single nucleotide polymorphism in the MDM2 promoter (SNP309) has been found to affect OS of advanced stage gastric adenocarcinoma (AD) and early stage squamous (SQ) cell carcinoma of the lung. The aim of this study was to evaluate the role of this polymorphism in the prognosis of esophageal cancer, another aerodigestive cancer. Methods: 150 early stage (E) and 118 locally advanced stage (LA) esophageal cancers were genotyped for MDM2 SNP309 using Taqman. The primary endpoint was overall survival (OS). Results: E disease: n=23 stage I; n=127 stage II. LA disease: n=93, Stage III; n=25, Stage IVA. AD comprised 215 (81%), while SQ comprised 45 (17%) of cases; 8 (3%) had poorly differentiated tumors. Median follow-up = 32 months. Median OS were 36 and 21 months for E and LA disease, respectively. Both histology and disease stage affected the relationship between SNP309 and esophageal cancer OS (see Table ). The wildtype T/T genotype conferred a worse OS in E patients (log-rank, p=0.03), especially those with AD (log-rank, p=0.003). In Cox proportional hazards interaction analyses, after adjusting for age, gender, stage and PS, there were statistically significant interactions between MDM2 SNP309 and disease stage (interaction p=0.004) and between MDM2 SNP309 and histologic subtype (AD vs. SQ)(interaction p=0.02). Thus, the direction of SNP309 association from our AD and E esophageal cancer patients are opposite to those of our SQ and LA esophageal cancer patients. However, our SQ and LA results are similar to the SQ lung cancer and advanced stage gastric cancers previously reported. This suggests that biologic mechanisms underpinning the prognostic role of SNP309 are dependent on extent of disease and histologic subtype. Conclusion: Histology and disease stage interact with the prognostic role of MDM2 SNP309 polymorphism in esophageal cancer OS.

[Table: see text]

No significant financial relationships to disclose.

Prognostic significance of nuclear excision (NER) and base excision (BER) DNA repair gene polymorphisms in esophageal cancer

2511

Background: DNA repair pathways are involved in cisplatin-induced damage (NER pathway) & radiation damage (BER pathway). Some single nucleotide polymorphisms (SNPs) of DNA repair genes are associated with DNA repair capacity, cancer risk & outcomes. We investigated the prognostic significance of 7 NER/BER SNPs on disease free (DFS) & overall survival (OS) in esophageal cancer. Methods: 150 patients with esophageal cancer treated with cisplatin-based chemoradiation & surgery were genotyped for BER (XRCC1 Arg399Gln; APE1 Asp148Glu; hOGG1 Ser326Cys) & NER (ERCC1 8092C/A; ERCC1 codon 118 C/T; XPD Asp312Asn; XPD Lys751Gln) SNPs. Analysis involved Kaplan-Meier curves, log-rank tests, and Cox proportional hazards models. Results: Median age: 63 years (range 28–80); 91% male; 100% ECOG performance status (PS) 0–1; adenocarcinoma 79%; stages IIA 22%, IIB 30%, III 33%, and IVA 15%. No SNPs were associated with stage or PS. Multiple NER SNP was independently prognostic for OS and DFS (see Table ). When compared to individuals who were wildtype in all four studied NER SNPs, individuals with variants in all four NER SNPs were associated with substantial improvement in OS (Adjusted Hazard Ratio (AHR) = 0.40, 95% confidence interval (CI) = 0.2–0.7) and DFS (AHR = 0.44, 95%CI = 0.2–0.8). Furthermore, increasing numbers of variant genotypes were associated with a progressive increase in OS & DFS when all seven NER/BER pathway SNPs were analysed together ( Table ). There was a 3.8- fold increase in OS (75 vs. 20 months) and five-fold increase in DFS (51 vs. 10 months) when comparing individuals with 6–7 SNPs with variant alleles to individuals with 0–1 SNPs with variant alleles. Conclusions: The ERCC1 8092 C/A, XPD Asp312Asn & XPD Lys751Gln SNPs in the NER pathway are associated individually with prognosis in esophageal cancer patients treated with cisplatin-based trimodality regimens. In addition, as the number of NER and BER SNPs carrying variant alleles increased, OS and DFS improved dramatically.

[Table: see text]

No significant financial relationships to disclose.

MMP1 1G/2G promoter polymorphism and risk of esophageal adenocarcinoma

10555

Background: The 2G allele of the MMP1 -1607 1G/2G promoter polymorphism creates an Ets binding site that leads to increased transcriptional and enzyme activity, particularly in the presence of growth factors and cytokines. This polymorphism has been associated with greater risk of cancer (e.g., renal cell, lung and oral cancers, glioblastomas) and cancer invasiveness (e.g., melanoma, cervical, lung and colorectal cancer). The aim of the current study was to evaluate the role of this MMP 1G/2G polymorphism in the risk of esophageal adenocarcinoma (EA). Methods: We evaluated 323 histologically confirmed EA cases and 464 healthy controls frequency-matched for age and gender. Genotyping of the MMP1 1G/2G promoter polymorphism involved a Taqman approach. All EAs had endoscopic evidence showing that the center of the tumors were located at or above the gastroesophageal junction. Odds Ratios (OR) were calculated using multivariate logistic regression, adjusted for age, gender, smoking status, and body-mass index (BMI) at the age of 18 years (to represent a healthy adult BMI). Results: Genotype frequencies were: 33% (1G/1G), 47% (1G/2G) & 20% (2G/2G) in controls; in cases, 26% (1G/1G), 50% (1G/2G) & 24% (2G/2G). 88% of cases were male. The MMP1 2G/2G and 1G/2G genotypes conferred a greater risk of EA, with adjusted ORs of 1.50 (95%CI=1.0–2.3) and 1.34 (95%CI=0.9–1.9), respectively, when compared with the wildtype 1G/1G genotype. The 2G allele (2G/2G + 1G/2G) conferred an adjusted OR of 1.38 (95%CI=1.0–1.9). By stage, the adjusted ORs for the 2G allele were 1.26 (95%CI=0.8–2.1), 1.45 (95%CI=0.9–2.3), & 1.54 (95%CI=0.9–2.7) for node negative, node-positive, and metastatic disease, respectively. Conclusions: The 2G allele of the MMP1 -1607 1G/2G polymorphism was associated with an increased risk of EA in this analysis. In addition, there was a non-significant trend towards conferring greater risk in the more advanced stages of EA, suggesting a possible role of this polymorphism in the invasiveness of this cancer.

No significant financial relationships to disclose.

Monitoring of microbiological water quality by real-time pcr

A new method was developed to evaluate the microbiological water quality. Deoxyribonucleic acid of water-borne bacteria was extracted and quantified using real-time polymer chain reaction detection system with a selected universal primer set. Quantification of the deoxyribonucleic acid in environmental water samples is independent of the culture condition, nutrient condition, or the bacterial metabolic states and can reflect the relatively small environmental changes which can not be detected through the other parameters. Therefore, this method can well represent the microbiological water quality. Compared with the conventional plate count method, deoxyribonucleic acid quantification has higher sensitivity, precision and reliability. The relationship between concentration of bacterial deoxyribonucleic acid and other water quality parameters was examined. Concentration of deoxyribonucleic acid was not well correlated with the plate count number, turbidity or other physical and chemical parameters.

Epidermal growth factor receptor polymorphisms and clinical outcomes in non-small-cell lung cancer patients treated with gefitinib

The-216G/T, -191C/A, intron 1 and Arg497Lys epidermal growth factor receptor (EGFR) polymorphisms were evaluated in 92 advanced non-small-cell lung cancer patients treated with gefitinib, an EGFR tyrosine-kinase inhibitor. Improved progression free survival (PFS) was found in patients homozygous for the shorter lengths of intron 1 polymorphism (S/S; S=16 or fewer CA repeats; log-rank test (LRT) P=0.03) and for patients carrying any T allele of the -216G/T polymorphism (LRT, P=0.005). When considered together, patients with intron 1 S/S genotype and at least one T allele of -216G/T had improved PFS (LRT P=0.0006; adjusted hazard ratio (AHR), 0.60 (95% confidence interval, 0.36-0.98)) and overall survival (LRT P=0.02; AHR, 0.60 (0.36-1.00)) when compared with all others. The T allele of -216G/T was also associated with significantly higher rates of stable disease/partial response (P=0.01) and a significantly higher risk of treatment-related rash/diarrhea (P=0.004, multivariate model). EGFR intron 1 and -216G/T polymorphisms influence clinical outcomes in gefitinib-treated non-small-cell lung cancer patients.

The extracellular signal-regulated kinase signaling pathway is involved in the modulation of morphine-induced reward by mPer1

Although there are clear interactions between circadian rhythms and drug addiction, mechanisms for such interactions remain unknown. Studies have shown that the circadian clock gene Period in Drosophila melanogaster could influence behavioral responses to cocaine, and the mouse homologues, mPer1 and mPer2, modulate cocaine sensitization and reward. In the present study, we applied DNAzyme targeting mPer1 to interfere the expression of mPer1 in CNS in mice, and studied its effects on morphine-induced reward and its molecular mechanism. The results demonstrated that the DNAzyme could attenuate the expression of mPer1 in CNS in mice and downregulate the increased extracellular signal-regulated kinase (ERK) activity induced by morphine in whole brain and the nucleus accumbens, the key region of drug addiction. Mice treated with morphine and injected intracerebroventricularly with DNAzyme did not show preference to the morphine-trained side. These results indicate that drug dependence seems to be influenced at least partially by mPer1 and its mechanism may involve the ERK signal pathway.

Genotypes and haplotypes of the VEGF gene are associated with higher mortality and lower VEGF plasma levels in patients with ARDS

BACKGROUND

Endothelial injury is an important prognostic factor in acute respiratory distress syndrome (ARDS). Vascular endothelial growth factor (VEGF) plays a critical role in endothelial destruction and angiogenesis. Genetic variations of the VEGF gene have been associated with VEGF production. A study was undertaken to investigate the impact of VEGF gene polymorphisms on the clinical outcomes of ARDS.

METHODS

Three VEGF polymorphisms (-460C/T, +405C/G and +936C/T) were determined in 1253 patients in an intensive care unit with risk factors for ARDS, 394 of whom developed ARDS. Patients were followed for assessment of 60 day survival. Plasma VEGF levels were measured in 71 patients with ARDS.

RESULTS

The +936TT (OR 4.29, 95% CI 1.12 to 16.40, p = 0.03) and +936CT+TT (OR 1.98, 95% CI 1.14 to 3.42, p = 0.01) genotypes were significantly associated with increased mortality from ARDS. Plasma VEGF levels in patients with ARDS with the +936CT+TT genotype were significantly lower than in subjects with the +936CC genotype (median 49 (IQR 16-98) pg/ml vs 112 (IQR 47-162) pg/ml, p = 0.02). At the haplotype level, haplotype TCT (-460T+405C+936T) was significantly associated with a higher rate of mortality (OR 2.89, 95% CI 1.30 to 6.43, p = 0.009) and haplotype CGT (-460C+405G+936T) was associated less strongly with increased mortality (OR 1.90, 95% CI 0.94 to 3.83, p = 0.07) in patients with ARDS. Lower plasma VEGF levels were correlated with the probability of haplotype CGT (coefficient = -0.26, p<0.05), but the same trend of correlation was not significant to haplotype TCT.

CONCLUSIONS

VEGF polymorphisms may contribute to the prognosis and inter-individual variations in circulating VEGF levels in patients with ARDS.

An auditory vigilance task for mental fatigue detection

An Auditory Vigilance Task (AVT) as a validation criterion for monitoring mental fatigue was proposed in this study. The biological basis of this task design is on the understanding that mental fatigue is a cortical deactivation. This AVT is simple to perform, free of learning curve and independent on acquired skills (aptitude, knowledge). The validity and sensitivity of this task was verified by a scientifically controlled 25-hour fatigue experiment recorded by Electroencephalogram (EEG). Results showed that this AVT is highly sensitive to changes during fatigue process. The effectiveness of this AVT was compared to one subjective rating scale (FSS). The 5-level fatigue EEG datasets (labeled by AVT and FSS respectively) were fed into Support Vector Machines (SVM). SVM test accuracy indicated that AVT is more effective than subject's own estimation. The results demonstrate conclusively that this AVT is suitable for fatigue detection study as a reliable validation criterion.

Role of acetylcholine transmission in nucleus accumbens and ventral tegmental area in heroin-seeking induced by conditioned cues

The involvement of cholinergic transmission in heroin self-administration and the reinstatement of heroin-seeking was examined in rats trained to nose-poke for i.v. heroin. Systemic treatment with physostigmine, an inhibitor of acetylcholinesterase, modestly reduced the acquisition and rate of heroin self-administration, and this suppression of heroin intake was reversed by pretreatment with scopolamine but not by mecamylamine. Following 10-14 days of self-administration, rats were left in the home environment for 14 days. Subsequently, rats were evaluated for extinction of nose-pokes during the first hour after being returned to the self-administration apparatus. One hour later a conditioned stimulus (house light, light in the nose-poke hole, sound of the infusion pump) was presented to initiate cue-induced reinstatement. Physostigmine produced a dose-dependent inhibition of cue-induced reinstatement, but only the dose of 0.5 mg/kg significantly decreased nose-poke responding in the extinction test. Chronic treatment with physostigmine (0.1 mg/kg) did not impair performance during acquisition of heroin self-administration. However, during a subsequent reinstatement test conducted in the absence of physostigmine pretreatment, heroin seeking was significantly below that of rats chronically pretreated with saline. To evaluate brain regions mediating the effects of systemic drug treatment on reinstatement, physostigmine was microinjected into the nucleus accumbens (NAc) or ventral tegmental area (VTA). Microinjection of physostigmine into the NAc prior to presenting conditioned cues inhibited the reinstatement of heroin-seeking, without affecting extinction responding. In contrast, microinjection of physostigmine into the VTA augmented the reinstatement induced by conditioned cues and extinction responding. Inactivation of either NAc or VTA by microinjecting tetrodotoxin blocked both extinction responding and cue-induced reinstatement. These data demonstrate that cholinergic transmission influences heroin self-administration and reinstatement. Moreover, cue-induced reinstatement was inhibited by physostigmine in the NAc and potentiated by cholinergic stimulation in the VTA.

Transition-metal-ethylene complexes as high-capacity hydrogen-storage media

From first-principles calculations, we predict that a single ethylene molecule can form a stable complex with two transition metals (TM) such as Ti. The resulting TM-ethylene complex then absorbs up to ten hydrogen molecules, reaching to gravimetric storage capacity of approximately 14 wt %. Dimerization, polymerizations, and incorporation of the TM-ethylene complexes in nanoporous carbon materials are also discussed. Our results are quite remarkable and open a new approach to high-capacity hydrogen-storage materials discovery.

Effect of femtosecond laser irradiation on structure of UV grade fused silica

A p-polarized femtosecond laser beam was used to irradiate a UV grade fused silica to create microchannels, which are useful for producing optical gratings or micro fluidics devices. The laser irradiated surface was characterized using optical microscope, stylus profiler, SEM, XRD and TEM. A special technique was used to protect the laser irradiated surfaces in preparing cross-sectional TEM samples. The XRD spectra and TEM observation reveal that structure of the fused silica remain amorphous after the femtosecond laser irradiation.

Ubiquitin E3 ligase WWP1 as an oncogenic factor in human prostate cancer

The gene for E3 ubiquitin ligase WWP1 is located at 8q21, a region frequently amplified in human cancers, including prostate cancer. Recent studies have shown that WWP1 negatively regulates the TGFbeta tumor suppressor pathway by inactivating its molecular components, including Smad2, Smad4 and TbetaR1. These findings suggest an oncogenic role of WWP1 in carcinogenesis, but direct supporting evidence has been lacking. In this study, we examined WWP1 for gene dosage, mRNA expression, mutation and functions in a number of human prostate cancer samples. We found that the WWP1 gene had copy number gain in 15 of 34 (44%) xenografts and cell lines from prostate cancer and 15 of 49 (31%) clinical prostate cancer samples. Consistently, WWP1 was overexpressed in 60% of xenografts and cell lines from prostate cancer. Mutation of WWP1 occurred infrequently in prostate cancer. Functionally, WWP1 overexpression promoted colony formation in the 22Rv1 prostate cancer cell line. In PC-3 prostate cancer cells, WWP1 knockdown significantly suppressed cell proliferation and enhanced TGFbeta-mediated growth inhibition. These findings suggest that WWP1 is an oncogene that undergoes genomic amplification at 8q21 in human prostate cancer, and WWP1 overexpression is a common mechanism involved in the inactivation of TGFbeta function in human cancer.

Cathepsin D-mediated proteolysis of apolipoprotein E: possible role in Alzheimer's disease

Proteolysis of apolipoprotein E (apoE) may be involved in the pathogenesis of Alzheimer's disease (AD). We previously identified aspartic protease(s) as possibly contributing to the proteolysis of apoE in human brain homogenates. The current study used biochemical and immunohistochemical methods to examine whether cathepsin D (catD) and cathepsin E (catE), candidate aspartic proteases, may be involved in apoE proteolysis. CatD was found to proteolyze both lipid-free recombinant full-length human apoE and lipidated human plasma full-length apoE (apoE4/dipalmitoylphosphatidylcholine-reconstituted discs). CatE was found to proteolyze lipid-free recombinant human apoE to a much greater extent than lipidated apoE. This proteolysis, as well as proteolysis of human apoE added to brain homogenates from apoE-deficient mice, was inhibited by pepstatin A (an aspartic protease inhibitor), but not by phenylmethanesulfonyl fluoride (a serine protease inhibitor). The major apoE fragment obtained with catD included the receptor-binding domain and had an apparent molecular weight similar to that found in human brain homogenates. There was little immunoreactivity for catE in AD brain tissue sections. In contrast, qualitative and quantitative analyses of immunostained sections of the frontal cortex revealed that catD and apoE are colocalized in a subset of predominantly dense-core neuritic plaques and in some neurofibrillary tangles. A positive correlation was observed between estimated duration of illness and the percentage of apoE-positive plaques that were also catD-positive. These results suggest that aspartic proteases, catD in particular, may be involved in proteolysis of apoE and perhaps contribute to the generation of apoE fragments previously implicated in AD pathology.