Expression of FOXP3 in esophageal squamous cell carcinoma relating to the clinical data

Forkhead box protein 3 (FOXP3) has been studied as a biomarker in many human malignancies recently. But in esophageal squamous cell carcinoma (ESCC) the studies are limited. In this study, expression of FOXP3 in ESCC tissue was evaluated in relation to the clinical data. Detection of FOXP3 mRNA was made by using quantitative real-time PCR while protein expression was assessed by immunocytochemistry (n = 112). The results were correlated to the clinical data including age, gender, carcinoma size, carcinoma differentiation, lymphatic invasion and pathological stage. A significantly higher FOXP3 expression in tumors was confirmed than in normal-appearing mucosa. The FOXP3 mRNA and protein expressions were higher in advanced stages (stage II B and III) than in early stages (stage I and stage II A). A significantly higher FOXP3 expression in tumors with lymph node metastasis was also confirmed than in those without lymph node metastasis. No significant correlation was found in age, gender, carcinoma size, or carcinoma differentiation. These results suggest that expression of FOXP3 was higher in ESCC tissue and was closely correlated to lymphatic invasion and pathological stage. It may imply that FOXP3 might play an important role in esophageal carcinoma progression.

Novel sulfated glucomannan-barium-alginate microcapsules in islet transplantation: significantly decreased the secretion of monocyte chemotactic protein 1 and improved the activity of islet in rats

The sulfated glucomannan can be used to filter the heparin-binding properties of cytokines. In this study, novel sulfated glucomannan-barium-alginate (SGA) microcapsules were prepared to encapsulate islets with barium-alginate (ABa) and calcium alginate-poly-l-lysine (APA) microcapsules as controls. SD rat islets were purified as donor cells to Lewis rats that had been treated with streptozotocin. Intraperitoneal transplantation was performed with about 3000 islet equivalent (IEQ) rat. At week three after transplantation, the concentrations of monocyte chemotactic protein-1 (MCP-1), interleukin (IL)-1 beta, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha in intraperitoneal fluid were determined using ELISA. At week 8, the islet cell mass in the abdominal microcapsules was excised to test insulin release. The EB-FDA fluorescence staining method was used to observe the functional activity of the islet cells. Compared with ABa and APA microcapsules, SGA microcapsules showed significantly decreased MCP-1 secretion by beta-cells. Also, the concentrations of cytokines IL-1beta, IFN-gamma, and TNF-alpha were decreased significantly. The activity of the transplanted islets was significantly improved in SGA microcapsules, which shielded against cytokines better than ABa or APA microcapsules and may serve as novel method.

Assessment of serum concentrations of Dkk1 as potential biomarker for esophageal squamous cell carcinoma

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Background: Esophageal squamous cell carcinoma (ESCC) is one of the most common fatal cancers worldwide due to the lack of an early disease screening strategy. Identification of diagnostic markers will greatly improve the morbid outcome. Dickkopf 1 (Dkk1) is a secreted antagonist of Wnt signaling pathway, an important pathway in tumorigenesis. The expressions of Dkk1 seem to be tumor-specific: reduced expressions have been seen in colorectal cancer, but elevated levels were reported for hepatoblastomas. In ESCC, the situation is less clear, for both elevation and reduction of Dkk1 were reported. The serum concentrations of Dkk1 have also been shown to be higher in ESCC patients’ sera in one study. In view of the varied outcome from Dkk1 tissue expressions and the scarce reports on Dkk1 serum concentration from ESCC patients, we therefore sought to determine the tissue expression and serum concentrations of Dkk1 as our first step to evaluate the potential of Dkk1 as a diagnostic marker for ESCC. Methods: The expression levels of Dkk1 in ten ESCC tumor and adjacent non-tumor tissues were examined by Western blot. Serum Dkk1 level of 168 samples were quantified in a double-blind fashion by ELISA (Dkk1 Duoset ELISA development kit from R & D Systems, Minneapolis, MN). To ensure that the serum Dkk1 detection was not affected by autoantibodies against Dkk1 present in sera, we also measured serum Dkk1 autoantibody levels by ELISA with modifications to the ELISA kit. Results: Seven out of ten of the tumors showed elevated Dkk1 level, while only two out of ten of the control normal tissue showed elevation. Surprisingly, after decoding of our serum samples into 80 patients and 88 normal controls, we found that Dkk1 level was significantly lower in patient sera (2.99ng/ml) than the normal samples (5.32ng/ml) (p=0.0001; t-test). The measurements were not obscured by the presence of Dkk1 autoantibodies, as they were not different between patient and control samples. Conclusions: Contrary to previous published results, we found Dkk1 is suppressed in patient sera, and thus our result undermines the potential of serum Dkk1 level as a predictive marker for ESCC. Further investigations will be needed to explain the discrepancies between the studies.

No significant financial relationships to disclose.

Enhanced remedial amendment delivery through fluid viscosity modifications: experiments and numerical simulations

Low-permeability zones are typically bypassed when remedial fluids are injected into subsurface heterogeneous aquifer systems. Therefore, contaminants in the bypassed areas may not be contacted by the amendments in the remedial fluid, which may significantly prolong remediation operations. Laboratory experiments and numerical studies have been conducted to investigate the use of a shear-thinning polymer (Xanthan gum) to improve access to low-permeability zones in heterogeneous systems. The chemicals sodium mono-phosphate and the surfactant MA-80 were used as the remedial amendments. The impact of polymer concentration, fluid injection rate, and permeability contrast in the heterogeneous systems has been studied in a series of eleven two-dimensional flow cell experiments. The Subsurface Transport over Multiple Phases (STOMP) simulator was modified to include polymer-induced shear-thinning effects. The experimental and simulation results clearly show that using the polymer leads to an enhanced delivery of remedial amendments to lower-permeability zones and an increased sweeping efficiency. An added benefit of using the polymer is the stabilization of the displacing front when density differences exist between displaced and displacing fluids. The modified STOMP simulator was able to predict the experimental observed fluid displacing behavior well and might be used to predict subsurface remediation performance when a shear-thinning fluid is used to remediate a heterogeneous system at larger scales.

Detection of let-7a microRNA by real-time PCR in colorectal cancer: a single-centre experience from China

Colorectal cancer, a heterogeneous disease arising from a complex series of molecular changes, is one of the world's leading causes of cancer deaths. MicroRNAs (miRNAs), an extensive class of small non-coding RNAs, have been implicated in cancer development and progression. One of the first miRNAs to be identified was let-7 miRNA, which has recently been found to be expressed at reduced levels in human lung cancer cells. We used a rapid stem-loop reverse transcription polymerase chain reaction method to quantify human let-7a miRNA expression in samples of human colorectal cancer. This method was able to detect let-7a miRNA in as little as 0.05 ng of total RNA from colorectal mucosa and its specificity was high (100%). Our results showed that the expression of let-7a miRNA was considerably reduced in two of eight patients. To our knowledge, this is the first study of Chinese patients to show reduced expression of endogenous let-7 miRNA in colorectal cancer.

Effect of left ventricular shape alteration on contractility and function

We have investigated the effect of left ventricular (LV) shape on contractility and ejection function. In this study, a new contractility index is developed in terms of the wall stress (sigma*, normalized with respect to LV pressure) by means of an LV ellipsoidal model. Using cine-ventriculography data, the LV ellipsoidal model (LVEM) major (B) and minor axes (A) are derived for the entire cardiac cycle. Thereafter, a new contractility index (CONT1) is derived as dsigma*/dt, incorporating the LV ellipsoidal shape factor. Also, another contractility index (CONT2) was developed in terms of the generated sigma* at the start of ejection phase, and maximized with respect to B/Ashape parameter, to obtain the optimal value of B/Aover the physiological ranges of the ratio of myocardial volume and LV volume. The in vivovalue of B/Aat the start of ejection is compared with this optimal value, and the LV contractility is evaluated in terms of the proximity of the in vivo B/Ato the optimal B/A. The results indicate that a non-optimal less-ellipsoidal shape (or more spherical) is associated with decreased contractility (and poor systolic function) of the LV, associated with a failing heart.

A non-invasive system for assessment of aortic stiffness in clinical practice

Previously aortic stiffness is frequently assessed through pulse pressure and pulse wave velocity (PWV) measurements. However, these methods need aortic pressure obtained by catheterization. A new model has been developed to rapidly determine the aortic pressure profile and simultaneously calculate aortic stiffness. Comparison between the aortic pressure result obtained from this and catheterization data demonstrates good agreement, while this method is non-invasive. This totally non-invasive method should be useful in assessing arteriosclerotic disease in clinical setting.

Adeno-associated virus 2-mediated gene transfer: role of a cellular serine/threonine protein phosphatase in augmenting transduction efficiency

We have documented that a cellular chaperone protein, FKBP52, when phosphorylated at tyrosine and/or serine/threonine (Ser/Thr) residues, interacts with the D-sequence in the inverted terminal repeats of the adeno-associated virus 2 (AAV) genome, inhibits the viral second-strand DNA synthesis, and leads to inefficient transgene expression from recombinant AAV vectors in certain cell types. We have also demonstrated that FKBP52 is dephosphorylated at tyrosine residues by T-cell protein tyrosine phosphatase (TC-PTP), and that deliberate overexpression of TC-PTP leads to more efficient viral second-strand DNA synthesis, and increased transgene expression. However, the identity of the putative Ser/Thr protein phosphatase that dephosphorylates FKBP52 at Ser/Thr residues has remained elusive. Using known inhibitors of Ser/Thr phosphatases, we have now identified protein phosphatase 5 (PP5) to be a candidate enzyme. Deliberate overexpression of PP5 in 293 cells, which does not influence cellular growth, leads to approximately 5-fold increase in the transduction efficiency of conventional single-stranded AAV vectors, but no significant enhancement in the transduction efficiency of self-complementary AAV vectors, suggesting that PP5 plays a role in AAV second-strand DNA synthesis. Electrophoretic mobility-shift assays show that in cells overexpressing PP5, the extent of the complex formation between FKBP52 and the AAV D-sequence is significantly reduced. These studies suggest that PP5-mediated dephosphorylation of FKBP52 at Ser/Thr residues augments viral second-strand DNA synthesis and enhances AAV transduction efficiency, which has implications in the optimal use of these vectors in human gene therapy.

Dose banding of chemotherapy doses at the Juravinski Cancer Centre

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Background: As the number and complexity of chemotherapy regimens increase, the demands on pharmacy services to reduce chemotherapy preparation and checking times continues to increase. Dose banding, a system whereby doses of intravenous cytotoxic drugs calculated on an individual basis are rounded up or down to predetermined standard doses (the maximum variation of the adjustment between standard dose and doses constituting each band is 5% or less) was identified as a strategy that could be used to address some of the issues around time pressures to help reduce patient waiting times for treatment. Methods: The project consisted of 3 phases; Phase I - literature review to identify dose banding publications; Phase II - selection of drugs to be banded for the pilot. The two drugs selected were 5FU and leukovorin, and Phase III - Time studies pre-, interim and post dose banding implementation to determine drug dispensing time and patients’ wait time for pharmacy related procedures. This occurred for a 2 week period (10 working days) either prior to implementation (pre- 819 patients studied), 4 days after implementation (interim - 854 patients studied) and 4 weeks after implementation (post - 785 patients studied). Results: Drug dispensing time did not decrease with dose banding (pre- 7.9 min, interim - 7.6 min and post - 9.4 min). However, the average patient wait time decreased after piloting the dose banding project (pre - 31.6 min, interim 23.7 min, and post - 27.8 min). The percentage of doses that were banded were 37.8% in the interim time study and 58.2% in the post time study. Conclusions: Although dose banding did not reduce dispensing time in this study, likely because the preparation for dispensing 5FU and leukovorin syringes is normally very simple and quick, patient’s wait time for pharmacy related procedures did decrease. This was probably due to contributions of other factors in the pharmacy process. A reduction in dispensing time could likely be achieved if more complex regimens were considered for dose banding. Dose banding could be used to increase capacity within the chemotherapy suite on the day of administration. It also allows for a better work schedule and increases efficiencies within the chemotherapy preparation and administration areas. (Sponsored by funds from Cancer Care Ontario)

No significant financial relationships to disclose.

HGS-ETR1, a fully human TRAIL-receptor 1 monoclonal antibody, induces cell death in multiple tumour types in vitro and in vivo

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in a variety of tumour cells through activation of TRAIL-R1 and TRAIL-R2 death signalling receptors. Here, we describe the characterisation and activity of HGS-ETR1, the first fully human, agonistic TRAIL-R1 mAb that is being developed as an antitumour therapeutic agent. HGS-ETR1 showed specific binding to TRAIL-R1 receptor. HGS-ETR1 reduced the viability of multiple types of tumour cells in vitro, and induced activation of caspase 8, Bid, caspase 9, caspase 3, and cleavage of PARP, indicating activation of TRAIL-R1 alone was sufficient to induce both extrinsic and intrinsic apoptotic pathways. Treatment of cell lines in vitro with HGS-ETR1 enhanced the cytotoxicity of chemotherapeutic agents (camptothecin, cisplatin, carboplatin, or 5-fluorouracil) even in tumour cell lines that were not sensitive to HGS-ETR1 alone. In vivo administration of HGS-ETR1 resulted in rapid tumour regression or repression of tumour growth in pre-established colon, non-small-cell lung, and renal tumours in xenograft models. Combination of HGS-ETR1 with chemotherapeutic agents (topotecan, 5-fluorouracil, and irinotecan) in three independent colon cancer xenograft models resulted in an enhanced antitumour efficacy compared to either agent alone. Pharmacokinetic studies in the mouse following intravenous injection showed that HGS-ETR1 serum concentrations were biphasic with a terminal half-life of 6.9–8.7 days and a steady-state volume of distribution of approximately 60 ml kg⁻¹. Clearance was 3.6–5.7 ml⁻¹ day⁻¹ kg⁻¹. These data suggest that HGS-ETR1 is a specific and potent antitumour agent with favourable pharmacokinetic characteristics and the potential to provide therapeutic benefit for a broad range of human malignancies.

Improved transduction of primary murine hepatocytes by recombinant adeno-associated virus 2 vectors in vivo

Adeno-associated virus 2 (AAV) vectors are currently in use in Phase I/II clinical trials for gene therapy of cystic fibrosis and hemophilia B. Although 100% of murine hepatocytes can be targeted by AAV vectors, the transgene expression is limited to approximately 5% of hepatocytes. Since the viral genome is a single-stranded DNA, and single strands of both polarities are encapsidated with equal frequency, it has been suggested that failure to undergo DNA strand-annealing accounts for the lack of efficient transgene expression. We and others, on the other hand, have proposed that failure to undergo viral second-strand DNA synthesis attributes to the observed low efficiency of transgene expression. We have previously documented that a cellular protein, designated FKBP52, when present in phosphorylated forms, inhibits the viral second-strand DNA synthesis, and consequently, limits transgene expression in nonhepatic cells, whereas unphosphorylated forms of FKBP52 have no effect. To further evaluate whether phosphorylated FKBP52 is also involved in regulating AAV-mediated transgene expression in murine hepatocytes, we generated transgenic mice overexpressing the cellular T-cell protein tyrosine phosphatase (TC-PTP) protein, known to catalyze dephosphorylation of FKBP52, as well as mice deficient in FKBP52. We demonstrate here that dephosphorylation of FKBP52 in TC-PTP transgenic (TC-PTP-TG) mice, and removal of FKBP52 in FKBP52-knockout (FKBP52-KO) mice results in efficient transduction of murine hepatocytes following tail-vein injection of recombinant AAV vectors. We also document efficient viral second-strand DNA synthesis in hepatocytes from both TC-PTP-TG and FKBP52-KO mice. Thus, our data strongly support the contention that the viral second-strand DNA synthesis, rather than DNA strand-annealing, is the rate-limiting step in the efficient transduction of hepatocytes, which should have implications in the optimal use of recombinant AAV vectors in human gene therapy.

[Effects of Ganoderma lucidum (Leyss ex Fr) Karst compound on the proliferation and differentiation of K562 leukemic cells]

A series of experiments including cell culture and benzidine staining test were undertaken to investigate the effects of Ganoderma lucidum(Leyss ex Fr) Karst Compound(GLC) on the proliferation and differentiation of K562 leukemic cells. The results showed that different concentrations of GLC(from 4 mg.ml-1 to 12 mg.ml-1) could promote human bone marrow granulocyte-macrophage colony forming unit (CFU-GM) proliferation, but suppressed the growth of K562 leukemic cell colonies, and IC50 was 9.2 mg.ml-1. The data from liquid culture demonstrated that GLC could suppress K562 cells proliferation in a dose-dependent(from 4 mg.ml-1 to 20 mg.ml-1) and time-dependent(from 1-5 days) manner. K562 cells could be induced to differentiate into more mature erythrocytic cells by 4 mg.ml-1 and 8 mg.ml-1 GLC. It is concluded that GLC may be a good medicine for leukemia therapy.

A possible role of initial cell death due to mechanical stretch in the regulation of subsequent cell proliferation in experimental vein grafts

The proliferation of vascular cells contributes to the formation of neointima and hypertrophy of the blood vessel wall. Here we show that mechanical stretch possibly regulates the proliferation of vascular cells via the mediation of cell death in a rat vein graft model. The wall of vein grafts is subject to a suddenly increased mechanical stretch due to exposure to arterial blood pressure. Such a stretch induces rapid cell death with a reduction in cell density by approximately 60% within the first day after surgery. The initial cell death was followed by an increase in the percentage of proliferating cells, as shown by a BrdU incorporation assay (1.55 +/- 1.27%, 8.48 +/- 2.27%, 11.93 +/- 2.36%, 6.36 +/- 1.77%, and 5.60 +/- 1.46% at days 1, 5, 10, 20, and 30, respectively). When mechanical stretch was reduced by restraining the vein graft using a polytetrafluoroethylene sheath, the percentage of proliferating cells reduced significantly (0.76 +/- 0.76%, 1.70 +/- 0.46%, 1.29 +/- 0.56%, 0.99 +/- 0.83%, and 0.47+/-0.52% at days 1, 5, 10, 20, and 30, respectively). A further reduction in cell density, induced by local administration of a cell death inducer ceramide to experimental vein grafts (without sheath), enhanced subsequent cell proliferation. In contrast, a prevention of cell death, induced by local administration of a cell death inhibitor tetrapeptide-aldehyde DEVD-CHO to experimental vein grafts (without sheath), significantly reduced subsequent cell proliferation. These results suggest that mechanical stretch induces cell death, which possibly mediates subsequent cell proliferation in the present model.

Mutations of tyrosine 537 in the human estrogen receptor-alpha selectively alter the receptor's affinity for estradiol and the kinetics of the interaction

Mutation of tyrosine 537 (Y537) of the human estrogen receptor-alpha (hERalpha) produces receptors having a range of constitutive activity, which suggests that this residue modulates the conformational changes of the receptor. We investigated the effect of several mutations at this position, to phenylalanine (Y537F), to serine (Y537S), and to glutamic acid (Y537E), on the hormone-binding properties of the receptor. The affinities of the wt, the Y537F mutant, and the Y537S mutant for estradiol were similar: K(a) = 2.2 +/- 0.2, 3.9 +/- 0.5, and 2.8 +/- 0.4 nM(-1), respectively. By contrast, the affinity of the Y537E mutant for estradiol was reduced 10-fold, K(a) = 0.2 +/- 0.1 nM(-1). All proteins bound [(3)H]estradiol with a positive cooperative mechanism (n(H) = 1.7-1.9), indicating they can form dimers. The wt receptor and the Y537S and Y537E mutants exhibited biphasic dissociation kinetics, which is also indicative of dimerization. Surprisingly, the half-lives of the slow component of the wt and the Y537E mutant were indistinguishable, 118 +/- 3.4 and 122 +/- 4.5 min, respectively, even though the affinity of the Y537E mutant for hormone was reduced 10-fold. The half-life of the slow component of the Y537S mutant was reduced to 96.5 +/- 3.8 min. Molecular models were constructed and compared to identify changes in the structure that correlate with the observed effects on hormone binding. Local alterations in hydrogen bonding, the position of side chains, and the position of the peptide backbone were observed. Taken together, these results show that mutations at Y537 selectively alter the affinity and kinetics of hormone binding to the receptor, and are consistent with the idea that the estradiol-estrogen receptor interaction can follow more than one pathway.

Control of the shape of a thrombus-neointima-like structure by blood shear stress

Fluid mechanical factors are thought to influence vascular morphogenesis. Here we show how blood shear stress regulates the shape of a thrombus-neointima-like tissue on a polymer micro-cylinder implanted in the center of the rat vena cava with the micro-cylinder perpendicular to blood flow. In this model, the micro-cylinder is exposed to a laminarflow with a known shear stress field in the leading region and a vortexflow in the trailing region. At 1, 5, 10, 20, and 30 days after implantation, it was found that the micro-cylinder was encapsulated by a thrombus-neointima-like tissue with a streamlined body profile. The highest growth rate of the thrombus-neointima-like tissue was found along the trailing and leading stagnation edges of the micro-cylinder. Blood shear stress in the laminar flow region was inversely correlated with the rate of thrombus formation and cell proliferation, and the percentage of smooth muscle a actin-positive cells. These biological changes were also found in the trailing vortex flow region, which was associated with lowered shear stress. These results suggest that blood shear stress regulates the rate of thrombus and neointimal formation and, thus, influences the shape of the thrombus-neointima-like structure in the present model.