Filamin A is essential for active cell stiffening but not passive stiffening under external force

The material properties of a cell determine how mechanical forces are transmitted through and sensed by that cell. Some types of cells stiffen passively under large external forces, but they can also alter their own stiffness in response to the local mechanical environment or biochemical cues. Here we show that the actin-binding protein filamin A is essential for the active stiffening of cells plated on collagen-coated substrates. This appears to be due to a diminished capability to build up large internal contractile stresses in the absence of filamin A. To show this, we compare the material properties and contractility of two human melanoma cell lines that differ in filamin A expression. The filamin A-deficient M2 cells are softer than the filamin A-replete A7 cells, and exert much smaller contractile stresses on the substratum, even though the M2 cells have similar levels of phosphorylated myosin II light chain and only somewhat diminished adhesion strength. In contrast to A7 cells, the stiffness and contractility of M2 cells are insensitive to either myosin-inhibiting drugs or the stiffness of the substratum. Surprisingly, however, filamin A is not required for passive stiffening under large external forces.

Electrical and photoresponse properties of an intramolecular p-n homojunction in single phosphorus-doped ZnO nanowires

The single-crystal n-type and p-type ZnO nanowires (NWs) were synthesized via a chemical vapor deposition method, where phosphorus pentoxide was used as the dopant source. The electrical and photoluminescence studies reveal that phosphorus-doped ZnO NWs (ZnO:P NWs) can be changed from n-type to p-type with increasing P concentration. Furthermore, we report for the first time the formation of an intramolecular p-n homojunction in a single ZnO:P NW. The p-n junction diode has a high on/off current ratio of 2.5 x 10(3) and a low forward turn-on voltage of approximately 1.37 V. Finally, the photoresponse properties of the diode were investigated under UV (325 nm) excitation in air at room temperature. The high photocurrent/dark current ratio (3.2 x 10(4)) reveals that the diode has a potential as extreme sensitive UV photodetectors.

Changes in condom use behaviours among clients of female sex workers in China

BACKGROUND

Clients of female sex workers (CFSWs) are at risk for HIV transmission; relevant surveillance and interventions for this vulnerable group are scarce. The China-UK HIV/AIDS Prevention and Care Project launched an enhanced intervention programme involving peer education, seminars, testing services and social gatherings and so forth, and two behavioural surveillance studies (BSS) targeting CFSWs in Suining, Sichuan.

METHODS

Two cross-sectional BSS (a baseline survey and an evaluative survey) were conducted in September 2005 and May 2006, respectively. In total, 356 and 372 respondents who patronised some low-end sex services were interviewed by peer interviewers. Another triangulation condom audit exercise was conducted in June 2006.

RESULTS

Prevalence of respondents using at least one prevention service increased from 50.3% in 2005 to 68.5% in 2006 (AOR = 2.2). Respondents of the evaluative survey compared with their counterparts of the baseline survey had lower prevalence of inconsistent condom users in the last 6 months (44.1% vs 77.0%; AOR = 0.2) and higher prevalence of condom use in the last episode of commercial sex (78.0% vs 41.5%; AOR = 4.9). The triangulation audit showed that condoms were used by 73.8% of CFSWs. The multivariate analysis shows that year of study (OR = 0.3), self-reported sexually transmitted disease symptoms (OR = 2.9), use of face-to-face counselling services (OR = 0.5) and so forth were significantly associated with inconsistent condom use during commercial sex in the last 6 months.

CONCLUSIONS

Condom use and service use behaviours changed in the study population over a time period when an enhanced intervention programme was implemented. Such effective programmes may be applied to other locations in China.

Drug resistance in the Chinese National Pediatric Highly Active Antiretroviral Therapy Cohort: implications for paediatric treatment in the developing world

China's National Pediatric ART Program began in 2005, in which 32 ART-experienced and 51 antiretroviral therapy (ART)-naïve children received paediatric formulations of (zidovudine or stavudine) plus lamivudine plus (nevirapine or efavirenz). Reverse transcriptase sequencing and analysis was performed on plasma samples with >1000 HIV copies/mL after one year of treatment. Thirty-four samples were sequenced. Nearly all patients had nucleoside reverse transcriptase inhibitor and non-nucleoside reverse transcriptase inhibitor mutations. High/intermediate resistance was found to lamivudine/emtricitabine in 31 patients; to didanosine, abacavir, stavudine and zidovudine in 18 patients; and to tenofovir in 11 patients. All had high-level resistance to nevirapine; all but one had high/intermediate-level resistance to efavirenz. Viral load was the only cohort characteristic significantly associated with developing resistance. Resistance to zidovudine, stavudine and tenofovir was more common in ART-experienced versus ART-naïve patients ( P = 0.02–0.05). Drug resistance is high in this cohort. Second-line therapy will require additional ART strategies and options, which are currently unavailable in most developing settings.

Clonal integration supports the expansion from terrestrial to aquatic environments of the amphibious stoloniferous herb Alternanthera philoxeroides

Effects of clonal integration on land plants have been extensively studied, but little is known about the role in amphibious plants that expand from terrestrial to aquatic conditions. We simulated expansion from terrestrial to aquatic habitats in the amphibious stoloniferous alien invasive alligator weed (Alternanthera philoxeroides) by growing basal ramets of clonal fragments in soils connected (allowing integration) or disconnected (preventing integration) to the apical ramets of the same fragments submerged in water to a depth of 0, 5, 10 or 15 cm. Clonal integration significantly increased growth and clonal reproduction of the apical ramets, but decreased both of these characteristics in basal ramets. Consequently, integration did not affect the performance of whole clonal fragments. We propose that alligator weed possesses a double-edged mechanism during population expansion: apical ramets in aquatic habitats can increase growth through connected basal parts in terrestrial habitats; however, once stolon connections with apical ramets are lost by external disturbance, the basal ramets in terrestrial habitats increase stolon and ramet production for rapid spreading. This may contribute greatly to the invasiveness of alligator weed and also make it very adaptable to habitats with heavy disturbance and/or highly heterogeneous resource supply.

Recycle of Alum recovered from water treatment sludge in chemically enhanced primary treatment

An investigation was made to study the feasibility of recovering the Alum from coagulation sludges and reusing it in chemically enhanced primary treatment (CEPT) process to make the CEPT more cost-effective and recover the resource (Alum) efficiently. The optimum condition and efficiency of the acidification method for Alum recovery from coagulation sludge were investigated in the test. The results show that when the recovery rate of Alum reaches its highest level, 84.5%, the reduction rate of sludge is 35.5%. It turns out that the capability of recovered coagulant to remove turbidity, UV(254) and COD are 96%, 46% and 53%, respectively. The results prove that the recovered coagulants could be used in CEPT and the efficiency of recovered coagulant to remove pollutants is similar to that of fresh coagulant. Although some substances will be enriched during recycle, they have little effect on the quality of treated wastewater. The experiments verify that it would be an advisable and cost-effective way to recover Alum from coagulation sludges in water treatment and chemical wastewater treatment, and it could be then recycled to CEPT as well as reduce sludge volume.

Application of cumulative odds logistic model on risk factors analysis for sexually transmitted infections among female sex workers in Kaiyuan city, Yunnan province, China

OBJECTIVES

To investigate the epidemiology of sexually transmitted infections (STI) among female sex workers (FSW) in Kaiyuan city, Yunnan province, China, and to identify risk factors associated with STI.

METHODS

A cross-sectional study of 737 FSW was carried out from March to May 2006, with confidential interviews and laboratory tests for STI. A cumulative logit model was used to evaluate the risk factors for STI.

RESULTS

The overall prevalence of HIV is 10.3%. The prevalence of syphilis, herpes simplex virus type 2, gonorrhoea, chlamydia and trichomonas was 7.5%, 68.1%, 8.3%, 25.9% and 10.6%, respectively. In multivariate cumulative odds logistic analysis, the factors associated with STI were education level, living in the entertainment location, injection drug use, non-injection drug use, over five clients in the previous week and inconsistent use of condoms with clients.

CONCLUSION

The findings highlight the gravity of the STI epidemic among FSW in China, where sexual transmission has now overtaken unsafe injection practices as the dominant mode of HIV transmission. Targeted intervention programmes for FSW should focus on increasing condom use, strengthening knowledge and awareness of STI/HIV and encouraging routine screening and treatment-seeking behaviours. Reducing the spread of STI also has profound implications for the prevention of HIV.

Phase II study of weekly administration of docetaxel (D) in combination with the epidermal growth factor receptor (EGFR) inhibitor erlotinib (E) in metastatic breast cancer (MBC)

Abstract #3124

Background: Single agent weekly docetaxel (D) is an active agent in the treatment of metastatic breast cancer (MBC) with response rates of 29% - 53%. Erlotinib (OSI-774, Tarceva®) is a tyrosine kinase inhibitor directed against EGFR, which is overexpressed in 30-40% of breast cancers, making EGFR an attractive treatment target. This study was designed to assess the combination of D and E in previously untreated recurrent and/or MBC.
 Methods: Adult patients with histologically confirmed MBC without prior chemotherapy for recurrence or metastases were eligible. Treatment plan was: D (initially 35 mg/m2 intravenous infusion weekly x 3 every 4 weeks) and E 150 mg orally daily uninterrupted. In patients with responding or stable disease, E was continued in 4 week cycles following a minimum of 6 cycles of D and E. Estimates of overall survival (OS) and progression free survival (PFS) were made by Kaplan-Meier method and the difference between groups by log-rank test. Tumor EGFR expression by immunohistochemisty and ER/PR was correlated with OS and PFS.
 Results: 39 female pts were enrolled between 12/02 and 8/06. The median age was 51 yrs (range 28-78). The median number of cycles of D and E received was 4 (range 1-26) and of E following D and E was 11 (range 2-18). EGFR, ER/PR and Her-2/neu status was determined on 35/39 patients. EGFR: 23 positive, 12 negative. ER/PR: 25 positive, 10 negative. Her-2/neu: 2 positive, 33 negative. Ten pts. were not evaluable for survival or response due to toxicity occurring within the first cycle. Best responses (n=29) ; PR 11(39%), SD 4 (14%), PD 13 (45%), and clinical benefit (PR+SD) 15 (54%). Median PFS was 8 mos (95% CI: 4.4-12.2). PFS for EGFR negative tumors appeared better than EGFR positive tumors (12 mos PFS 33% vs. 23%) but was not significant (p = 0.53). There was no difference in OS between these groups (p=0.38). PFS and OS for ER/PR positive pts was significantly higher than ER/PR negative pts 6 mos PFS 67% vs. 25% (p= 0.009) and 2 yr OS 53.9% vs. 12.5% (p=0.015). , All patients were included for toxicity assessment (n-39). The first 26 pts received planned D dose of 35mg/m2. Because of non-hematologic toxicity, trial was subsequently modified to start D at 25 mg/m2. Grade 3 or 4 Leukopenia was seen in 15% pts. Principal non-hematologic grade 3-4 toxicities included anorexia, diarrhea, and fatigue (18% pts).
 Conclusions: Combination therapy for advanced breast cancer with docetaxel and erlotinib shows promising activity with favorable response compared with other studies. There was no significant association with EGFR expression and PFS, however this combination is more favorable for ER positive patients. Randomized trials for ER positive disease is warranted to further investigate the efficacy of this combination compared to single agent docetaxel.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3124.

A 6 gene molecular predictor of lapatinib related benefit: from cell line models to clinical trials

Abstract #58

Background: Identification of molecular predictors of response is an important aspect of individualized cancer treatment. Responses to lapatinib (L), an oral inhibitor of HER2 and EGFR, approved in combination with capecitabine for HER2+ metastatic breast cancer (MBC), were evaluated in a panel of BC cell lines. Computational approaches were used to identify transcripts that quantitatively associate with response to L in the cell line panel that were then tested in 2 clinical trials.
 Methods: The clinical utility of a 6-gene predictor was tested retrospectively using a branched-chain DNA assay in paraffin-embedded archival tumor tissue from patients (pts) with HER2 negative or untested MBC tumors enrolled in a phase III trial of paclitaxel (P) vs. P+L, and from pts with HER2 positive MBC enrolled in a L monotherapy trial. Expression of HER2 transcript using the branched-chain assay was compared with HER2 fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) status; discordant cases were analyzed. Response patterns for pts with HER2+ tumors and a computational model that predicts L sensitivity or resistance is described.
 Results: Ingenuity analysis of the mRNA predictors of response to L identified in the BC cell line panel revealed saturated gene networks with HER2 as a major node. The 6-gene predictor of response was comprised of 2 genes associated with sensitivity to L: HER2 and GRB7; 4 genes associated with resistance to L: CRK, ACOT9, FLJ31079, and DDX5. Expression results for the 6 genes and progression-free survival (PFS) data were available for 159 pts on L+P. Median PFS in the branched-chain HER2+ group was 32.9 wks vs. 22.4 wks in the HER2-negative group. The 6-gene predictor was used to predict response to L in the HER2+ pts. Comparison of PFS in the 24 “L sensitive” tumors vs. 25 “L resistant” tumors indicated that the predictor, derived from cell-line analyses, had the potential to predict clinical response to L in pts treated with L+P (HR=0.58; 95% CI=0.30-1.11; p=0.07). The 6-gene predictor was further tested in an independent L monotherapy study in pts with HER2 FISH+ MBC. Comparison of PFS in the 24 “L sensitive” tumors vs. 28 “ L resistant” tumors reconfirmed the potential of the 6-gene predictor to enrich for HER2+ pts most likely to experience clinical benefit from L (HR=0.40; 95% CI=0.19-0.84; p=0.015). Further testing is ongoing.
 Conclusions: This study suggests that molecular predictors of clinical response can be developed through an analysis of response from a collection of 50 BC cell lines. The identification of a L specific 6-gene assay is promising as a clinical predictor of benefit from L in pts with HER2+ BC.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 58.

MUC1 expression in early-stage triple-negative breast cancer

Abstract #3009

Background. Triple-negative breast cancer (TNBC) comprises ∼10-15% of newly-diagnosed early-stage breast cancer. Most TN tumors are high grade and have a high incidence of recurrence and distant metastases. Patients with early stage TNBC usually do not receive any maintenance systemic therapy beyond standard cytotoxic chemotherapy and may therefore benefit from novel experimental therapies, including immunotherapy. MUC1 is a tumor antigen expressed on differentiated tumor cells, including BC, and therefore represents an ideal target for MUC1-based vaccination. In this study, we evaluated TNBC for the expression of MUC1 by immunohistochemical (IHC) analysis.
 Material and Methods. Fifty-three cases of ER(-) PR(-) HER-2/neu(-) early-stage BC were evaluated for expression of the MUC1 glycoprotein by IHC stain analysis. Immunoreactivity was graded based on the intensity and percent of tumor cells staining for MUC1. Intensity of staining was graded as negative (0), positive (1) or strongly-positive (2), and the percent of tumor cells staining positively was graded from 0 to 100%. A specimen was considered positive if immunoreactive cells were found in at least 5% of tumor cells. An overall score of 0 to 2.0 was then calculated for each case by multiplying the intensity of staining by the percent of tumor cells staining positively.
 Results. Forty nine of the fifty three cases of TNBC (92%) were MUC1+ by IHC stain analysis. The mean score was 0.90, with a range of 0 to 1.9. Cases were evenly distributed over this range, and the majority of cases (66%) exhibited moderate to strong expression of MUC1 (score 0.5 to 1.90). A minority of cases (26%) demonstrated weak expression, and 8% of cases lacked expression of MUC1 by study criteria.
 Discussion. MUC1 expression has been documented in the epithelium of secretory tubules, acini, and intralobular ducts of normal breast tissue and in breast carcinoma of undefined subtype. However, this is the first study to specifically evaluate TNBC for the expression of MUC1. The results of our study suggest that the vast majority of cases of early stage TNBC express MUC1. Since other MUC1+ tumors such as prostate, pancreatic and ER+ breast cancer have been successfully vaccinated with MUC1-based peptide vaccines, this study suggests that consideration may be given to patients with early stage TNBC as possible candidates for such novel MUC1-based vaccines after having completed standard therapies for TNBC.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3009.

Ferric coagulant recovered from coagulation sludge and its recycle in chemically enhanced primary treatment

An investigation was conducted to study the feasibility of ferric coagulant recovery from chemical sludge and its recycle in chemically enhanced primary treatment (CEPT) to make the process more cost-effective, as well as reduce sludge volume. The optimum conditions and efficiency of the acidification for ferric coagulant recovery from coagulation sludge were investigated. Experimental results showed that the recovered coagulants can be used in CEPT and the pollutants removal efficiency is similar to that of fresh coagulant, and for some aspects the effect of recovered coagulants is better than that of fresh ones, such as turbidity removal. Although some substances will be enriched during recycle, they have little effect on treated wastewater quality. Acidification condition also had significant influence on reduction of sludge volume. The efficiency of coagulant recovery had a linear relationship with sludge reduction. Experiments verify that it would be a sustainable and cost-effective way to recover ferric coagulant from coagulation sludge in water treatment and chemical wastewater treatment, and then recycle it to CEPT, as well as reduce sludge volume.

Spatially resolved photoluminescence study of single ZnO tetrapods

ZnO tetrapods and nanowires were fabricated by a simple method of thermal evaporation of pure Zn powder in the air. These nanostructures, formed in different temperature regions of the same apparatus, displayed distinct photoluminescence (PL) characteristics. Spatially resolved PL measurements on legs of individual tetrapods show that the green luminescence (GL) decreases with decreasing leg diameter, and there was no detectable GL from nanowires grown simultaneously. These PL properties suggest that the green luminescence may not come from surface states, but rather from bulk defects.

Connexin 43 hemichannels contribute to the propagation of apoptotic cell death in a rat C6 glioma cell model

Gap junctions (GJs) have been demonstrated to communicate cell death signals from apoptotic to healthy cells, thereby spatially extending apoptosis. Before being incorporated into GJs, hemichannels (hemi-GJs) are normally closed but recent evidence suggests that they can be opened by various messengers and conditions, thereby forming a pore through which molecules can enter or leave the cell potentially leading to cell death. The aim of this study was to determine the contribution of GJs and hemichannels in the communication of apoptosis toward surrounding cells. We induced apoptosis in C6 glioma cells stably transfected with connexin (Cx)43, with cytochrome C (cytC) using in situ electroporation and found that healthy surrounding cells underwent apoptotic transformation. Work with various cell death markers, wild-type (WT) and Cx43-expressing cells, inhibitors of GJs and/or hemichannels, and Cx43 gene silencing showed that GJs contribute to the spread of apoptosis in a zone next to where apoptosis was triggered whereas hemichannels also promoted cell death beyond this area. Buffering cytoplasmic Ca(2+) changes inhibited the spread of apoptosis in both cases. We conclude that Cx43 hemichannels, in concert with their GJ counterparts, play a role in communicating cytC-induced apoptotic cell death messages.

Analysis of the interindividual conservation of T cell receptor alpha- and beta-chain variable regions gene in the peripheral blood of patients with systemic lupus erythematosus

The aim of this study was to find conserved motifs in specific T cell receptor (TCR) alpha- and beta-chains, and to analyse the association between complementarity determining region 3 (CDR3) spectratype and systemic lupus erythematosus (SLE) activity. TCR alpha-and beta-chain CDR3 spectratypes were analysed in 20 SLE patients. The CDR3 spectratypes of three patients were monitored over time, and the CDR3 regions of clonally expanded T cells were sequenced. CDR3 spectratype analysis showed prominent usage of TCR AV8, AV14, AV23, AV30, AV31, BV2, BV8, BV11, BV14, BV16, BV19 and BV24 families in SLE patients. The CDR3 spectratype showed dynamic change correlating with SLE activity. The sequence of the CDR3 region in clonally expanded T cells suggested a conserved GGX amino acid motif in both alpha- and beta-chains. The Ja34 and Jb2s1 region genes were found in high frequency. Both TCR Valpha and Vbeta gene usage is highly restricted in SLE, suggesting that the TCRs recognize a limited number of antigenic epitopes. The conserved motifs and limited use of joining region genes may indicate the recognition of similar antigenic epitopes in multiple individuals.

Evaluation of cotton rats as a model for severe acute respiratory syndrome

Experimental studies were conducted to evaluate two species of cotton rats, Sigmodon hispidus and Sigmodon fulviventer, as a model for severe acute respiratory syndrome (SARS). Blood and turbinate wash samples, and lung tissue were collected from each animal at different time points after SARS coronavirus (CoV) infection for determining the growth curve of virus, if any, by the standard infectivity assay in Vero E6 cells. In addition, sections of the lung, liver, spleen, and kidney were taken and used for histology analysis. All animals were observed daily for signs of illness, and in some experiments, animals were weighed on the day when they were sacrificed. The results indicated that the cotton rat species, S. hispidus and S. fulviventer, were not a useful model for either SARS-CoV infection or disease. This observation was supported by the absence of any signs of illness, the failure to consistently demonstrate virus in the blood and tissues, and the absent of any notable histopathology. However, infected animals were capable of producing neutralizing antibodies against SARS-CoV, suggesting the seroconversion did occur. Further studies are warranted to consider other animal species in efforts to find better animal models for the evaluation of SARS-CoV vaccines and antiviral drugs.