HEF1, a novel target of Wnt signaling, promotes colonic cell migration and cancer progression

Misregulation of the canonical Wnt/β-catenin pathway and aberrant activation of Wnt signaling target genes are common in colorectal cancer (CRC) and contribute to cancer progression. Altered expression of human enhancer of filamentation 1 (HEF1; also known as NEDD9 or Cas-L) has been implicated in progression of melanoma, breast, and CRC. However, the regulation of HEF1 and the role of HEF1 in CRC tumorigenesis are not fully understood. We here identify HEF1 as a novel Wnt signaling target. The expression of HEF1 was upregulated by Wnt-3a, β-catenin, and Dvl2 in a dose-dependent manner, and was suppressed following β-catenin downregulation by shRNA. In addition, elevated HEF1 mRNA and protein levels were observed in CRC cell lines and primary tumor tissues, as well as in the colon and adenoma polyps of Apc(Min/+) mice. Moreover, HEF1 levels in human colorectal tumor tissues increased with the tumor grade. Chromatin immunoprecipitation (ChIP) assays and promoter analyses revealed three functional T-cell factor (TCF)-binding sites in the promoter of HEF1 responsible for HEF1 induction by Wnt signaling. Ectopic expression of HEF1 increased cell proliferation and colony formation, while downregulation of HEF1 in SW480 cells by shRNA had the opposite effects and inhibited the xenograft tumor growth. Furthermore, overexpression of HEF1 in SW480 cells promoted cell migration and invasion. Together, our results determined a novel role of HEF1 as a mediator of the canonical Wnt/β-catenin signaling pathway for cell proliferation, migration, and tumorigenesis, as well as an important player in colorectal tumorigenesis and progression. HEF1 may represent an attractive candidate for drug targeting in CRC.

Measurement of the parity-violating longitudinal single-spin asymmetry for W± boson production in polarized proton-proton collisions at sqrt[s] = 500 GeV

We report the first measurement of the parity-violating single-spin asymmetries for midrapidity decay positrons and electrons from W+ and W- boson production in longitudinally polarized proton-proton collisions at sqrt[s] = 500 GeV by the STAR experiment at RHIC. The measured asymmetries, A(L)(W+) = -0.27 ± 0.10(stat.) ± 0.02(syst.) ± 0.03(norm.) and A(L)(W-) = 0.14 ± 0.19(stat.) ± 0.02(syst.) ± 0.01(norm.), are consistent with theory predictions, which are large and of opposite sign. These predictions are based on polarized quark and antiquark distribution functions constrained by polarized deep-inelastic scattering measurements.

GaN-Based MSM uv Photodetectors

Results obtained from interdigital metal-semiconductor-metal (MSM) type of GaN based UV photodetectors are presented. MSM devices were fabricated using two types of GaN; high-resistive GaN and Mg doped GaN. For the high-resistive GaN detector, the lowest dark current is ∼0.1 nA and the UV responsivity of the device was about 460 AAV at a DC bias of 30 V. The Mg doped GaN exhibited large gains, 1150 A/W at 2.0 V, but at much higher dark currents, 400 nA. The high gain in this device is not well understood but was attributed to an ‘avalanche’ effect and is under investigation. It was found that the surface plasma treatment plays an important role in the device performance. After an appropriate plasma treatment the detectors showed higher responsivity with lower dark current.

Development of High-Efficiency Zn2SiO4:Mn Thin Films for Flat Panel Cathodoluminescent Displays

Zn2SiO4:Mn thin films were deposited and studied as thin film phosphors for flat panel cathodoluminescent displays. Crystallized films with improved electrical conductivity were obtained after conventional and rapid thermal annealings in a N2 environment at 850Xy11100 °C for 0.25 to 60 minutes. A maximum cathodoluminescent efficiency of 1.3 Lm/W was achieved under dc excitation at 1500 volts. The luminescent emission from these thin films was peaked around 525 nm. The decay time of these films was controlled in the range of 2 to 10 ms by varying the deposition and annealing parameters. The fast response time of these thin films overcomes the long decay limitation of the Zn2SiO4:Mn powder phosphor in practical display applications.

Approach to high-frequency, cavity-enhanced Faraday rotation in fluids

Recent work demonstrating detection of nuclear spin magnetization via Faraday rotation in transparent fluids promises novel opportunities for magnetic resonance imaging and spectroscopy. Unfortunately, low sensitivity is a serious concern. With this motivation in mind, we explore the use of an optical cavity to augment the Faraday rotation experienced by a linearly polarized beam traversing a sample fluid. Relying on a setup that affords reduced sample size and high-frequency modulation, we demonstrate amplification of regular (i.e., nonnuclear) Faraday rotation of order 20. Extensions of the present methodology that take into account the geometric constraints imposed by a high-field magnet may open the way to high-sensitivity, optically-detected magnetic resonance in the liquid state.

Technological Development for Commercialization of Amorphous Silicon Based Multijunction Modules

Some of the significant steps in technological development for large-scale commercialization of amorphous silicon (a-Si:H) based multijunction photovoltaic modules are presented. These developments are establishing a high quality baseline process for manufacturing large-area ( ˜ 8 ft2) a-Si:H/a-SiGe:H tandem junction modules with improved stabilized conversion efficiency, throughput, yield, and reduced materials usage.

Mechanism of Cu removal during CMP in H2O2-glycine based slurries

Hydroxyl radical generation has been observed during Cu CMP using hydrogen peroxide-glycine based slurries. While the Cu dissolution/polish rates increased with increasing glycine concentration, the copper dissolution rate decreased with increasing peroxide concentration indicating the occurrence of both dissolution and passive film formation during CMP. This is further confirmed by both in situ and ex situ electrochemical experiments.

Expressions of BAFF/BAFF receptors and their correlation with disease activity in Chinese SLE patients

B-cell activating factor belonging to tumour necrosis factor family (BAFF) is essential for B-cell survival and function through interaction with its receptors BAFF receptor 3 (BR3), B-cell maturation antigen (BCMA) and/or transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), though BCMA and/or TACI can also bind to a proliferation-inducing ligand (APRIL). We evaluate the correlation of the expressions of these ligands/receptors with different clinical manifestations of systemic lupus erythematosus (SLE). Levels of BAFF and APRIL in plasma from 73 SLE patients were determined by enzyme-linked immunosorbent assay. Expressions of BR3, TACI and BCMA on CD19+ B cells were detected by flow cytometry. Clinical data were collected and disease activity was evaluated using SLEDAI-2000. SLE patients had elevated BAFF and APRIL levels in their plasma. BAFF levels correlated positively with SLEDAI while negatively with the BR3 protein expression on CD19+ B cells (p < .05). The detected BR3 protein expression in SLE patients was reduced on CD19+IgD+CD27-, CD19+IgD+CD27+ as well as CD19+IgD-CD27+ B cells compared to the counterparts of healthy controls (p < .001), whereas SLE patients did not differ from healthy controls in BR3 mRNA levels. In untreated new-onset patients, the expression rate of BR3 on CD19+ B cells correlated negatively with SLEDAI (p < .05). Elevation of BAFF and reduction of BR3 on CD19+ B cells were more obvious in those with lupus nephritis (LN, p < .05). TACI expression on CD19+ B cells was up-regulated only in those subjects with LN (p < .05). Elevated plasma BAFF and reduced BR3 protein expression on peripheral B cells could act as biomarkers for active disease in SLE patients. High expression of TACI may indicate the occurrence of LN.

Rapid 5-fluorouracil plasma quantification by immunoassay: Validation with FOLFOX6 clinical samples

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Background: 5-fluorouracil (5-FU) is one of the most widely used chemotherapy agents in the treatment of colorectal cancer. Studies over the last 30 years have demonstrated wide pharmacokinetic variability of 5-FU which can lead to undue toxicity and suboptimal treatment. Recent clinical studies have demonstrated that managing plasma 5-FU levels and adjusting doses to target steady state concentrations effectively minimizes toxicity and improves outcome.

Methods: An existing immunoassay using a novel antibody to 5-FU was modified to directly quantify 5-FU in patient plasma samples without any sample pretreatment. The assay was adapted to Beckman Coulter AU analyzers and to Roche COBAS c 111 analyzer. Method comparison to LC-MS/MS, limit of detection (LoD), lower limit of quantitation (LLoQ), precision, and linearity of the assay were evaluated. The assay was also validated by testing samples of patients being treated by modified FOLFOX6 from an on-going clinical trial ( NCT00943137 ).

Results: The modified immunoassay was confirmed to have a linear reportable range from 85 to 18,000ng/mL and a LoD of 52ng/mL. The immunoassay was established to have good precision (CV<6%) around the medical decision points for FOLFOX and FOLFIRI regimens. Method comparison of the immunoassay obtained by testing 58 clinical samples from patients under 5-FU treatment provides excellent correlation to LC- MS/MS: Deming slope 1 ± 0.05, R > 0.98. Another 82 samples of patients on modified FOLFOX6 regimen from clinical trial (( NCT00943137 ) were tested using the immunoassay and range of these sample were reported to be from 95 to 2,970 ng/mL.

Conclusions: The assay provided the performance required to rapidly quantify 5-FU plasma concentrations. It was fast (time to 1st result < 10 minutes), precise, correlated well to a physical method, required only 100uL sample on the analyzer and 7ul for actual testing per assay, and was easily adapted to a variety of clinical analyzers. Clinical and pharmacokinetic laboratories could use this assay to introduce an evidence-based approach to optimize 5-FU dosing that would have higher throughput, simpler methodology, and require less labor, space or expense than the physical methods.

[Table: see text]

Primary malignant melanoma of the esophagus: a study of clinical features, pathology, management and prognosis

Primary malignant melanoma of the esophagus (PMME) is a rare disease that is characterized by aggressive invasion, early metastasis, and poor prognosis. Treatment protocols are not well-established. To understand this condition more precisely, we performed a retrospective review of eight cases of PMME diagnosed at the Thoracic Department of the Cancer Center at Sun Yat-Sen University between 1985 and 2009. Eight PMME patients (five men and three women) with a mean age of 58 years (range: 48 to 72 years) were included. Dysphagia was the most common presenting symptom. All patients underwent an Ivor-Lewis esophagogastrectomy and lymph node dissection with postoperative adjuvant chemotherapy. One patient with stage III/pT4N0M0 underwent postoperative chemotherapy plus radiotherapy. Four patients died of distant metastases. The median survival time was 28 months (range: 11 months to 6 years). Our data confirm that PMME is a highly aggressive disease with a poor prognosis. If the diagnosis is suspected or confirmed as PMME, and the patients have no distal metastases or extensive lymph node enlargement, we suggest that surgery should be the first choice of treatment. With regard to adjuvant therapy, we recommend the addition of chemotherapy. The role of radiotherapy remains questionable and requires further investigation.

Phase II trial of irinotecan and cisplatin combination as first-line chemotherapy in patients with advanced esophageal squamous-cell carcinoma: An interim report

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Background: Although the irinotecan and cisplatin combination has been used in esophageal cancer treatment, we tested the combination specifically in unresectable or metastatic esophageal squamous cell carcinoma with different doses to decrease the toxicity and keep the efficacy.

Methods: Patients were eligible if they had histologic proof of unresectable or metastatic squamous cell carcinoma of the esophagus, between 18-75 years of age with a Karnofsky performance status ≥ 80. No prior chemotherapy was allowed. Patients were treated with irinotecan 130 mg/m2 and cisplatin 60 mg/m2 repeated 3 weeks. Response was evaluated every two cycles of treatment by using RECIST criteria. The sample size was calculated using Simon's 2-stage design. The primary end point of the study was objective response rate. The second end points are PFS and toxicity. Accrual was planned to a total of 46 patients with the targeted response rate of 50%. The first stage requires at least 7 or more out of 16 patients to have a confirmed partial or complete response before proceeding to the second stage.

Results: Twenty one patients have been enrolled so far, of which 16 patients were assessable for response. The overall response rate was 43.8%(7/16), including one complete response (6.3%) and six partial response (37.5%). Among 13 patients who presented with dysphagia at baseline, 10 (62.5%) had the symptom either completely resolved or significantly improved. The most common toxicities were neutropenia, diarrhea and alopecia. Seven patients (33.3%) developed grade 3 neutropenia and one had (4.8%) with febrile neutropenia. One patient (4.8%) had grade 3 diarrhea. There were no treatment-related deaths.

Conclusions: The combination of irinotecan plus cisplatin with lower doses showed equivalent efficacy and less toxicity in patients with unresectable or metastatic squamous-cell carcinoma of the esophagus. The study is ongoing.

No significant financial relationships to disclose.

Study of genotypic variations and protein expression of the xCT subunit of cystine/glutamate transporter in pancreatic cancer

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Background: The plasma membrane xCT cystine-specific subunit of the cystine/glutamate transporter contributes to chemotherapy resistance in pancreatic cancer by regulating intracellular glutathione levels and protecting cancer cells against oxidative stress. We previously noted that the rs7674870 single nucleotide polymorphism (SNP) of xCT correlated with overall survival in pancreatic cancer and may be predictive of platinum resistance. There are no data regarding xCT protein expression in pancreatic cancer or the functional significance of this SNP.

Methods: Paraffin-embedded core and surgical biopsy tumor specimens from 49 patients with metastatic pancreatic adenocarcinoma were analyzed by immunohistochemistry (IHC) using an xCT specific antibody (Novus Biologicals). xCT protein IHC expression scores (product of intensity and percentage of staining cells) were analyzed in relation to overall survival and genotype of the patients using the one factor ANOVA test, Kaplan-Meier plot, log-rank test, and Cox regression analysis. Overall survival was measured from the date of diagnosis to the date of death or last follow-up.

Results: Positive xCT expression was detected in 38 (78%) of the 49 samples, and 9 (18%) patients had high levels of expression. High xCT expression was associated with lower overall survival as compared with low expression (5.1 months versus 8.8 months; p = 0.119). In a multivariate Cox regression model with adjustment for prognostic parameters of age, sex, performance status and CA19-9 level, high xCT expression was associated with a 2.1-fold increased risk of death (p = 0.096). Performance status also correlated with overall survival (p = 0.027). Preliminary analysis on the genotype-phenotype association (n = 12) indicated that xCT expression was higher with the TT genotype than the TC/CC genotype (p = 0.115), which is consistent with the previous observation that the TT genotype was associated with reduced survival.

Conclusions: These data provide supporting evidence for a possible role of cystine/glutamate transporter xCT subunit in pancreatic cancer progression and survival. Further pharmacogenomic and clinicopathologic studies are ongoing.

No significant financial relationships to disclose.

Differential expression of small ubiquitin-like modifier family of proteins in patients with colorectal adenocarcinoma

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Background: The cytotoxic effects of radiation and chemotherapy are mediated in part by DNA damage. The small ubiquitin-like modifier (SUMO) family of proteins regulates DNA repair pathways by activating factors involved in homologous recombination (HR) or non- homologous end joining (NHEJ). Our objective was to determine the potential role of SUMO proteins in patients with colorectal cancer.

Methods: We first assessed two established colorectal cancer cell lines (HCT116 and HT29) and two normal colonic mucosa cell populations utilizing ultra high-throughput expression analysis (Solexa) to examine differential expression of genes involved in SUMOylation (SAE1, SAE2, PIAS-1, and DNAPKcs). To verify the clinical relevance of SUMOylation in colorectal cancer, we obtained archived specimens from patients with colorectal cancer (n=51) and examined the expression of these proteins in both benign and malignant tissue by immunohistochemistry (IHC).

Results: Ultra high-throughput expression analysis of cancer and normal cells revealed a 10 to 15-fold upregulation of SAE2 (heterodimer of the E1 activation enzyme in SUMOylation), a 10 to 11-fold upregulation of DNAPKcs (catalytic subunit in NHEJ repair pathway), and a 6-fold upregulation of SAE1 in cancer cells. In contrast, PIAS-1 showed similar expression levels between cancer and normal colonic cells. By IHC, SAE1 and SAE2 were highly expressed in 65% and 53% of tumor specimens, respectively; but only in 7% and 0% of normal tissues, respectively. DNAPKcs was also highly expressed in tumor tissues (63%) with corresponding low expression (0%) in normal tissues. Corroborating the cell line results, PIAS-1 was infrequently expressed in both tumor (10%) and normal tissues (0%).

Conclusions: We are the first to demonstrate the differential expression of SUMO proteins in colorectal cancer cell lines and in clinical specimens. SUMO proteins have a role in DNA repair and their expression in colorectal cancer may modify tumor response to chemoradiotherapy.

No significant financial relationships to disclose.