Expression of the TMPRSS2:ERG fusion gene predicts cancer recurrence after surgery for localised prostate cancer

The prostate-specific gene, TMPRSS2 is fused with the gene for the transcription factor ERG in a large proportion of human prostate cancers. The prognostic significance of the presence of the TMPRSS2:ERG gene fusion product remains controversial. We examined prostate cancer specimens from 165 patients who underwent surgery for clinically localised prostate cancer between 1998 and 2006. We tested for the presence of TMPRSS2:ERG gene fusion product, using RT–PCR and direct sequencing. We conducted a survival analysis to determine the prognostic significance of the presence of the TMPRSS2:ERG fusion gene on the risk of prostate cancer recurrence, adjusting for the established prognostic factors. We discovered that the fusion gene was expressed within the prostate cancer cells in 81 of 165 (49.1%) patients. Of the 165 patients, 43 (26.1%) developed prostate-specific antigen (PSA) relapse after a mean follow-up of 28 months. The subgroup of patients with the fusion protein had a significantly higher risk of recurrence (58.4% at 5 years) than did patients who lacked the fusion protein (8.1%, P<0.0001). In a multivariable analysis, the presence of gene fusion was the single most important prognostic factor; the adjusted hazard ratio for disease recurrence for patients with the fusion protein was 8.6 (95% CI=3.6–20.6, P<0.0001) compared to patients without the fusion protein. Among prostate cancer patients treated with surgery, the expression of TMPRSS2:ERG fusion gene is a strong prognostic factor and is independent of grade, stage and PSA level.

Genome scan implicates adhesion biological pathways in secondary leukemia

The genetic risk factors for etoposide-induced leukemia with MLL translocations remain largely unknown. To identify genetic risk factors for and novel characteristics of secondary leukemia, we profiled 116,204 single nucleotide polymorphisms (SNPs) in germline and paired leukemic cell DNA from 13 secondary leukemia/myelodysplasia cases and germline DNA from 13 matched and 156 unmatched controls, all with acute lymphoblastic leukemia treated with etoposide. We analyzed global gene expression from a partially overlapping cohort. No single locus was altered in most cases. We discovered 81 regions of loss of heterozygosity (LOH) in leukemic blasts and 309 SNPs whose allele frequencies differed in cases vs controls. Candidate genes were prioritized on the basis of genes whose SNPs or expression differentiated cases from controls or showed LOH or copy number change in germline vs paired blast DNA from the 13 cases. Three biological pathways were altered: adhesion, Wnt signaling and regulation of actin. Validation experiments using a genome scan for etoposide-induced leukemogenic MLL chimeric fusions in 15 HapMap cell lines also implicated genes involved in adhesion, a process linked to de novo leukemogenesis. Independent clinical epidemiologic and in vitro genome-wide approaches converged to identify novel pathways that may contribute to therapy-induced leukemia.

Chimeric immune receptors (CIRs) specific to JC virus for immunotherapy in progressive multifocal leukoencephalopathy (PML)

Progressive multifocal leukoencephalopathy (PML) is a deadly brain disease caused by the polyomavirus JC (JCV). The aim of this study is to develop 'designer T cells' armed with anti-JCV TCR-based chimeric immune receptors (CIRs) by gene modification for PML immunotherapy. Two T cell lines specific to two dominant CTL epitopes derived from JCV VP1 protein (termed p36 and p100) from an HLA-A0201+ PML survivor were generated for TCR cloning. Two distinct dominant TCR alpha chains (Valpha6 and Valpha12) and a unique TCR beta chain (Vbeta5.1) were cloned from the p36-specific cell line, while only one alpha (Valpha8.6) and one beta (Vbeta2) chains were dominant in the p100-specific line. Retroviral constructs encoding CIRs were created with the extracellular domains of TCR alpha and beta chains fused to the transmembrane and cytoplasmic portions of CD3zeta (ValphaCalphaCD3zeta or VbetaCbetaCD3zeta). Cellular expression and screening for binding specific peptide-HLA-A0201 tetramer confirmed the reactivity of the p100 TCRalphabeta and of one of the two pairs of p36 TCRalphabeta (Valpha12 and Vbeta5.1). Functional tests confirmed CIR-expressing T cells secreted cytokines and expressed potent cytotoxicity on contact with A0201+ B-lymphoblastoid line loaded with peptides and/or with HLA-A0201+ cells expressing native JCV VP1 protein. In conclusion, anti-JCV designer T cells were generated.

Three-dimensional finite element model of the two-layered oesophagus, including the effects of residual strains and buckling of mucosa

This study was carried out to develop a two-layered finite element model of the oesophagus. The outer muscle and inner mucosal layer were constructed individually with different mechanical properties and zero-stress opening angles. With the model, two simulations were performed. First, the distention of oesophageal wall under the pressurized state was investigated, from which the effects of residual strains on the stress distribution were evaluated. Second, the buckling modes were determined using a linear eigenvalue analysis. The self-contact capability in ABAQUS was applied to simulate the folding of mucosa under the muscle contraction. The first simulation indicated that, by taking the residual strains into account, the mucosa undertook a very small portion of stress and the luminal pressure almost transmitted completely to the outer muscle layer. On the other hand, the folding of mucosa was shown to be able to reduce the contractile force of circular muscle to maintain the lumen closure. In conclusion, the preliminary study demonstrated the feasibility of simulating the oesophageal peristaltic transport using finite element analysis.

Expression and clinicopathological significance of oestrogen-responsive ezrin?radixin?moesin-binding phosphoprotein 50 in breast cancer

AIMS

Ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) is a post synaptic density-95/Disk-large/ZO-1 homologous domain-containing protein that is involved in the linkage of integral membrane proteins to the cytoskeleton and plays an important role in cell signalling. To gain insights into its biological relevance, this study examined expression of EBP50 in two cohorts of breast carcinoma.

METHODS AND RESULTS

Forty-nine breast carcinoma tissue specimens were first examined by both immunohistochemistry and RNA in situ hybridization. EBP50 expression was correlated with various clinicopathological variables. The relative abundance of EBP50 mRNA in breast carcinomas and their corresponding normal tissue was compared using reverse transcriptase-polymerase chain reaction (RT-PCR). EBP50 immunoreactivity was then further independently validated in 120 breast carcinomas on tissue microarrays. EBP50 immunoreactivity was observed in morphologically normal and cancerous epithelial cells contrasting with the adjacent immunonegative stromal cells. An elevated cytoplasmic accumulation of EBP50 protein was readily detected in 73.5-80% of breast carcinomas. EBP50 immunoreactivity was significantly associated with tumour stage, lymph node and oestrogen receptor status. These immunohistochemical observations were further validated using RNA in situ hybridization and RT-PCR. EBP50 immunoreactivity was significantly correlated with the mRNA expression level.

CONCLUSION

Oestrogen-responsive EBP50 may play an important role in tumour progression and might be a potential marker of invasiveness for breast cancer.

The role of contrast-enhanced ultrasound in planning treatment protocols for hepatocellular carcinoma before radiofrequency ablation

AIM

To evaluate the clinical value of contrast-enhanced ultrasound (CEUS) for patients with hepatocellular carcinoma (HCC) in identifying the tumour number, ablation range and feeding vessels before ultrasound-guided radiofrequency ablation (RFA), and to compare the efficacy of RFA after CEUS with the efficacy of RFA after non-enhanced ultrasonography (US) without contrast medium administration.

MATERIALS AND METHODS

From 2002 to 2005, 81 patients with 110 HCCs underwent CEUS with SonoVue before RFA treatment (group A). Eighty six patients with 112 HCCs who underwent US without contrast enhancement before RFA served as the control group (group B). The average diameters of the lesions in group A and group B were 3.6+/-1.1cm and 3.5+/-1.1cm, respectively. There were no significant differences in clinical data between the two groups. Regular follow-up after treatment was performed using contrast-enhanced computed tomography (CECT). After treatment, complete necrosis was defined as the absence of viable tissue in treated tumours at the 1-year follow-up CECT.

RESULTS

Using CEUS an additional seven small lesions (< or =2.0 cm) were found compared with those found using CECT and conventional US. CEUS showed that 56.4% of lesions (62/110 tumours) were larger in size and 49.1% (54/110 tumours) became more irregular in shape during the arterial phase than on conventional US. Feeding vessels were detected using CEUS in 52 (91.2%) of 57 lesions that were larger than 3.5 cm. The follow-up period was at least 1 year for each case. The complete tumour necrosis rate in group A was significantly higher than that in group B (92.2% versus 83.0%; p=0.036).

CONCLUSION

CEUS can be used to more accurately define the size and contour of lesions, and to detect additional small or satellite lesions and the feeding vessel of HCC tumours. CEUS provided important information for designing the ablation protocol, and might improve the efficacy of RFA.

Identification and characterization of a novel p42.3 gene as tumor-specific and mitosis phase-dependent expression in gastric cancer

Multiple genetic alterations are attributed to gastric cancer (GC); however, only a few critical genes have been identified so far. In this study, we isolated and characterized a novel gene p42.3, represented as tumor-specific and mitosis phase-dependent expression protein in GC cell line BGC823. Our data showed that the expression of p42.3 was cell cycle-dependent in GC cell lines. Moreover, p42.3 was specifically expressed in primary GC tissues but not in the matched normal mucosa of stomach, and this gene was expressed in diverse embryonic tissues. Furthermore, significant suppression of cell proliferation and tumorigenicity were detected and G(2)/M phase arrest was observed in cell line BGC823 depleted of p42.3 expression by RNAi technique, and we confirmed the expression changes of cyclin B1 and Chk2 following the silence of p42.3. Taken together, we cloned and characterized p42.3 gene that was specifically expressed in GC tumors but not in normal gastric mucosa, and the gene was associated with M-phase regulation. Moreover, p42.3 might be involved in cell proliferation and tumorigenesis; therefore, this gene might have potential applications in the diagnosis or treatment of GC.

Effect of pioglitazone on the expression of inflammatory cytokines in attenuating rat cardiomyocyte hypertrophy

Pioglitazone, one of the synthetic peroxisome proliferator-activated receptor (PPARgamma) agonists, has been found to inhibit inflammatory response. However, it is not known yet whether the preventive effect of pioglitazone on cardiac hypertrophy is related to its antiinflammatory function. The objective of this study was to investigate the role of pioglitazone in attenuation of cardiac hypertrophy and its relation to the inhibitory effect on the inflammatory cytokine expression in cultured neonatal rat cardiomyocytes. The mRNA expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), interleukin (IL)-1beta, IL-6, and PPARgamma was measured by using RT-PCR. Cardiomyocyte hypertrophy was induced by stimulating angiotensin II (Ang II) and evaluated both by measuring surface area of cardiac myocyte and 3H-leucine incorporation. The expressions of IL-1beta, IL-6, ANP, and BNP were significantly enhanced, whereas that of PPARgamma was significantly reduced in Ang II-induced hypertrophic cardiomyocytes. Pioglitazone decreased cardiac myocyte surface area and inhibited 3H-leucine incorporation into cardiomyocytes. Furthermore, pioglitazone upregulated the suppressed expression of PPARgamma and attenuated the increased IL-1beta and IL-6 expression. The effect of pioglitazone might be associated with PPARgamma activation and the consequent antiinflammatory function in prevention and treatment of cardiac hypertrophy.

Using HapMap Tools in Pharmacogenomic Discovery: The Thiopurine Methyltransferase Polymorphism

One purpose of the International HapMap Project is to provide a genome-wide resource to discover pharmacogenetic determinants of drug response. The thiopurine methyltransferase (TPMT) 719A>G single-nucleotide polymorphism (SNP) causes decreased TPMT activity, increased intracellular thiopurines, and drug toxicities. Using HapMap cell lines and 3.3 million SNPs, we tested whether the TPMT 719A>G SNP could be identified as predicting TPMT phenotype. Assuming TPMT was a candidate gene, five SNPs and four haplotypes predicted TPMT phenotype, two of which were in complete linkage disequilibrium with the functional 719A>G SNP. We also used a genome-wide approach to rank all 17,542 genes as predictors of TPMT activity. A TPMT haplotype, HAP1, significantly predicted TPMT phenotype; however, haplotypes of 96 genes ranked higher than TPMT. Our findings show that HapMap resources are useful for pharmacogenetic discovery when the candidate gene is known, but challenges remain for definitive gene identification when a genome-wide agnostic approach is employed.

3D Mechanical properties of the layered esophagus: experiment and constitutive model

The identification of a three dimensional constitutive model is useful for describing the complex mechanical behavior of a nonlinear and anisotropic biological tissue such as the esophagus. The inflation tests at the fixed axial extension of 1, 1.125, and 1.25 were conducted on the muscle and mucosa layer of a porcine esophagus separately and the pressure-radius-axial force was recorded. The experimental data were fitted with the constitutive model to obtain the structure-related parameters, including the collagen amount and fiber orientation. Results showed that a bilinear strain energy function (SEF) with four parameters could fit the inflation data at an individual extension very well while a six-parameter model had to be used to capture the inflation behaviors at all three extensions simultaneously. It was found that the collagen distribution was axial preferred in both layers and the mucosa contained more collagen, which were in agreement with the findings through a pair of uniaxial tensile test in our previous study. The model was expected to be used for the prediction of stress distribution within the esophageal wall under the physiological state and provide some useful information in the clinical studies of the esophageal diseases.

MEPE expression in osteocytes during orthodontic tooth movement

MEPE and DMP1 may play a role in mineralisation and demineralisation within the osteocyte microenvironment. Our earlier studies showed that DMP1 is mechanically responsive [Gluhak-Heinrich J, Ye L, Bonewald LF, Feng JQ, MacDougall M, Harris SE, et al. Mechanical loading stimulates dentin matrix protein 1 (DMP1) in osteocytes in vivo. J Bone Min Res 2003;18(5):807-17].

OBJECTIVES

To examine the effect of mechanical loading on the expression of MEPE using mouse tooth movement model, and compare this effect to that on DMP1.

METHODS

In situ hybridisation and immunohistochemistry was performed on 38 treated and 38 control bone sites loaded 6-72 h. ImageJ was used for quantification of mRNA expression in osteocytes.

RESULTS

Alveolar osteocytes showed high basal level of MEPE that decreased during the first day of loading, followed by 2.8-fold stimulation at day 3, and returning to a control level by day 7.

CONCLUSION

The osteocyte specific mechanical stimulation of MEPE was delayed and different, compared to that of DMP1. This suggests a distinct role of MEPE and DMP1 in the response of osteocytes to mechanical loading in vivo.

Instability of the two-layered thick-walled esophageal model under the external pressure and circular outer boundary condition

The mucosal folding is a phenomenon observed for some biological tissues, including the pulmonary airway and gastrointestinal tract. In order to understand the mechanism of the formation of mucosal folding, a thick-walled two-layered cylindrical mathematical model was developed to investigate the buckling behavior under the external pressure and circular outer boundary condition. With the finite element method, the validity and accuracy of the proposed model was verified. The results showed that the fold number was in the range of 4-6, which was agreed with the experimental observation for the mucosal folding of a porcine esophagus. The fold number was found to decrease with the increase in the ratio of the inner to outer material stiffness. The increase in the thickness of inner layer also caused a slight declination of the fold number. Since the effects of both the material and geometrical nonlinearities have been accounted for, this model is more general to be used for the prediction of the buckling behavior of the layered structure with a wide range of thickness ratios and/or stiffness ratios.

A novel MASH1 enhancer with N-myc and CREB-binding sites is active in neuroblastoma

Neuroblastoma is one of the most common solid tumors in childhood. With the aim of developing a targeting vector for neuroblastoma, we cloned and characterized an enhancer in the 5'-flanking regions of the MASH1 gene by a random-trap method from a 36 kb cosmid DNA. The enhancer-containing clone was identified by the expression of GFP when transfected into neuroblastoma cell lines. The enhancer-luciferase activity is higher in neuroblastoma cell lines, IMR32, BE2 and SH-SY5Y, compared with those in non-neuroblastoma cell lines, U1242 glioma, N417 small cell lung cancer and EOMA hemangioma. The core enhancer was determined within a 0.2 kb fragment, yielding three- to fourfold higher activity than that of the MASH1 promoter alone in IMR32 and BE2. This area possesses GATA- and CREB-binding sites, as well as the E-box. EMSA on this area demonstrated that CREB/ATF could bind the DNA. Chromatin immunoprecipitation assay revealed that N-myc, CREB, and co-activators CBP and PCAF, but not HDAC1, are bound to the core enhancer at the same time as the co-activators and N-myc bind to the promoter. This supports the idea that the commonly overexpressed genes HASH1 and N-myc are regulated in concert, confirming their importance as prognostic markers or targets for therapy.

Identification of differential melanocortin 4 receptor agonist profiles at natively expressed receptors in rat cortical astrocytes and recombinantly expressed receptors in human embryonic kidney cells

Using cAMP accumulation as a functional readout, we pharmacologically characterized the response of native melanocortin receptors in cultured rat astrocytes, and found this response to be mediated by the melanocortin 4 receptor (MC4R). Melancortin agonists stimulate cAMP in a concentration-dependent manner in both astrocytes and human embryonic kidney cells recombinantly expressing rat MC4R (HEK-rMC4R), however, the relative potency and intrinsic activity of both small molecule and peptide agonists are reduced in the native system. As such, the small molecules THIQ, NBI-702 and MB243 display 43, 30 and 18% of the maximal response elicited by alpha-MSH in astrocytes. Likewise, the peptides MTII and ACTH display 55 and 72% of the maximal response elicited by alpha-MSH in these cells. In contrast, all of these compounds elicit full agonist responses with similar intrinsic activity to alpha-MSH in HEK-rMC4R cells. MC4R mRNA was detected in astrocytes, however radioligand binding experiments failed to detect measurable MC4R in astrocyte membranes, in contrast to membranes from HEK-rMC4R cells that display a binding site density of 18.1+/-1.5 fmol/mg. We propose that the divergent observations in functional activity between the cell types reflect differences in receptor expression and that caution should be exercised when interpreting agonist activity in over-expression systems for the purposes of drug discovery.