Steroid Receptor RNA Activator Protein (SRAP): A Potential New Prognostic Marker for Estrogen Receptor-Positive/Node-Negative/Younger Breast Cancer Patients

Purpose: The steroid receptor RNA activator (SRA) is a functional RNA suspected to participate in the mechanisms underlying breast tumor progression. This RNA is also able to encode for a protein, SRAP, whose exact function remains to be determined. Our aim was to assess, in a large breast cancer cohort, whether levels of this protein could be associated with outcome or established clinical parameters.Experimental Design: Following antibody validation, we have assessed SRAP expression by tissue-microarray (TMA) analysis of 372 tumors with known steroid receptor and node status. Clinical follow-up was available for all the corresponding patients. Immunohistochemical scores were independently determined by two investigators and averaged. Statistical analyses were performed using standard univariate and multivariate tests.Results: SRAP levels were significantly (Mann-Whitney rank sum test, P<0.05) higher in estrogen receptor-alpha positive (ER+, n = 273), in progesterone receptor positive (PR+, n= 256) and in older patients (age ≥ 65 years, n = 183). When considering ER+ tumors, PR+ tumors, or young patients (< 65 years), patients with high SRAP expression had a significantly (Mantel-Cox test, P < 0.05) worse breast cancer specific survival (BCSS) than patients with low SRAP levels. SRAP also appeared as a very powerful indicator of poor prognostic for BCSS in the subset of ER+, node negative and young breast cancer patients (Cox regression analysis, n = 60, BCSS Hazard Ratio=13.937, P<0.0001).Conclusion: Our data suggest that SRAP might be a new predictor of breast cancer specific survival in younger breast cancer patients with ER+/node negative tumors.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2017.

MicroRNA-7 modulates CD98 expression during intestinal epithelial cell differentiation

The transmembrane glycoprotein CD98 regulates multiple cellular functions, including extracellular signaling, epithelial cell adhesion/polarity, amino acid transport, and cell-cell interactions. MicroRNAs post-transcriptionally regulate gene expression, thereby functioning as modulators of numerous cellular processes, such as cell differentiation, proliferation, and apoptosis. Here, we investigated if microRNAs regulate CD98 expression during intestinal epithelial cell differentiation and inflammation. We found that microRNA-7 repressed CD98 expression in Caco2-BBE cells by directly targeting the 3'-untranslated region of human CD98 mRNA. Expression of CD98 was decreased, whereas that of microRNA-7 was increased in well-differentiated Caco2-BBE cells compared with undifferentiated cells. Undifferentiated crypt cells isolated from mouse jejunum showed higher CD98 levels and lower levels of mmu-microRNA-706, a murine original microRNA candidate for CD98, than well-differentiated villus cells. Importantly, microRNA-7 decreased Caco2-BBE cell attachment on laminin-1, and CD98 overexpression recovered this inhibition, suggesting that microRNA-7 modulates epithelial cell adhesion to extracellular matrix, which in turn could affect proliferation and differentiation during the migration of enterocytes across the crypt-villus axis, by regulating CD98 expression. In a pathological context, the pro-inflammatory cytokine interleukin 1-beta increased CD98 expression in Caco2-BBE cells by decreasing microRNA-7 levels. Consistent with the in vitro findings, microRNA-7 levels were decreased in actively inflamed Crohn disease colonic tissues, where CD98 expression was up-regulated, compared with normal tissues. Together, these results reveal a novel mechanism underlying regulation of CD98 expression during patho-physiological states. This study raises microRNAs as a promising target for therapeutic modulations of CD98 expression in intestinal inflammatory disorders.

Pathogenic bacteria induce colonic PepT1 expression: an implication in host defense response

BACKGROUND & AIMS

Expression of the di/tripeptide transporter PepT1 has been observed in the colon under inflammatory conditions; however, the inducing factors and underlying mechanisms remain unknown. Here, we address the effects of pathogenic bacteria on colonic PepT1 expression together with its functional consequences.

METHODS

Human colonic HT29-Cl.19A cells were infected with the attaching and effacing enteropathogenic Escherichia coli (EPEC). Wild-type and PepT1 transgenic mice or cultured colonic tissues derived from these mice were infected with Citrobacter rodentium, a murine attaching and effacing pathogen related to EPEC.

RESULTS

EPEC induced PepT1 expression and activity in HT29-Cl.19A cells by intimately attaching to host cells through lipid rafts. Induction of PepT1 expression by EPEC required the transcription factor Cdx2. PepT1 expression reduced binding of EPEC to lipid rafts, as well as activation of nuclear factor-kappaB and mitogen-activated protein kinase and production of interleukin-8. Accordingly, ex vivo and in vivo experiments revealed that C rodentium induced colonic PepT1 expression and that, compared with their wild-type counterparts, PepT1 transgenic mice infected with C rodentium exhibited decreased bacterial colonization, production of proinflammatory cytokines, and neutrophil infiltration into the colon.

CONCLUSIONS

Our findings demonstrate a molecular mechanism underlying the regulation of colonic PepT1 expression under pathologic conditions and reveal a novel role for PepT1 in host defense via its capacity to modulate bacterial-epithelial interactions and intestinal inflammation.

Evaluation of the cytotoxicity of a two photon absorbing fluorescence compound on human HepG2 cells and its application to tracking human hepatic cancer cells in mice

Small organic dyes have been applied widely in fluorescence imaging techniques for biomedical research. We investigated the cytotoxicity of a novel fluorescent dye, trans-4-(N-2-hydroxyethyl-N-ethyl amino)-4'-(dimethyl amino) stilbene (DMAHAS), on human hepatocellular carcinoma (HepG2) cells using methyl thiazolyl tetrazolium(MTT), a neutral red assay, a Coomassie brilliant blue assay, and flow cytometric analysis. Our results showed that DMAHAS had live cell permeability, stable cytosolic localization and no significant cytotoxicity to HepG2 cells. We explored its application further for tumor cell tracking in a human liver tumor xenograft mouse model. Tumor xenografts were examined by fluorescence imaging and conventional histological methods. In addition, a method based on DMAHAS release was developed for tumor-specific cytotoxicity analysis. Our study indicated that DMAHAS is a reliable probe for tumor tracking and fluorescence imaging.

Inflammasomes are differentially expressed in cardiovascular and other tissues

To determine the expression of components in Toll-like receptors (TLRs)/Nod-like receptors (NLRs)/inflammasome/caspase-1/interleukin (IL-1)-beta pathway, we examined the expression profiles of those genes by analyzing the data from expression sequence tag cDNA cloning and sequencing. We made several important findings: firstly, among 11 tissues examined, vascular tissues and heart express fewer types of TLRs and NLRs than immune and defense tissues including blood, lymph nodes, thymus and trachea; secondly, brain, lymph nodes and thymus do not express proinflammatory cytokines IL-1beta and IL-18 constitutively, suggesting that these two cytokines need to be upregulated in the tissues; and thirdly, based on the expression data of three characterized inflammasomes (NALP1, NALP3 and IPAF inflammasome), the examined tissues can be classified into three tiers: the first tier tissues including brain, placenta, blood and thymus express inflammasome(s) in constitutive status; the second tier tissues have inflammasome(s) in nearly-ready expression status (with the requirement of upregulation of one component); the third tier tissues, like heart and bone marrow, require upregulation of at least two components in order to assemble functional inflammasomes. Our original model of three-tier expression of inflammasomes would suggest a new concept of tissue inflammation privilege, and provides an insight to the differences among tissues in initiating acute inflammation in response to stimuli.

Temporal and spatial analysis of clinical and molecular parameters in dextran sodium sulfate induced colitis

Background

Inflammatory bowel diseases (IBD), including mainly ulcerative colitis (UC) and Crohn's disease (CD), are inflammatory disorders of the gastrointestinal tract caused by an interplay of genetic and environmental factors. Murine colitis model induced by Dextran Sulfate Sodium (DSS) is an animal model of IBD that is commonly used to address the pathogenesis of IBD as well as to test efficacy of therapies. In this study we systematically analyzed clinical parameters, histological changes, intestinal barrier properties and cytokine profile during the colitic and recovery phase.

Methods

C57BL/6 mice were administered with 3.5% of DSS in drinking water for various times. Clinical and histological features were determined using standard criteria. Myeloperoxidase (MPO) activity, transepithelial permeability and proinflammatory mediators were determined in whole colon or proximal and distal parts of colon.

Results

As expected after administration of DSS, mice manifest loss of body weight, shortening of colon length and bloody feces. Histological manifestations included shortening and loss of crypts, infiltration of lymphocytes and neutrophil, symptoms attenuated after DSS withdrawal. The MPO value, as inflammation indicator, also increases significantly at all periods of DSS treatment, and even after DSS withdrawal, it still held at very high levels. Trans-mucosal permeability increased during DSS treatment, but recovered to almost control level after DSS withdrawal. The production of proinflammatory mediators by colonic mucosa were enhanced during DSS treatment, and then recovered to pre-treated level after DSS withdrawal. Finally, enhanced expression of proinflammatory mediators also revealed a different profile feature in proximal and distal parts of the colon.

Conclusion

Experimental colitis induced by DSS is a good animal model to study the mechanisms underlying the pathogenesis and intervention against IBD, especially UC.

A first-in-human phase I study to evaluate the pan-PI3K inhibitor GDC-0941 administered QD or BID in patients with advanced solid tumors

3501

Background: The PI3K-PTEN-AKT signaling pathway is deregulated in a wide variety of cancers. GDC-0941 is a potent and selective oral inhibitor of the class I PI3K with 3 nM IC50 for the p110-alpha subunit in vitro and 28 nM IC50 in a cell-based pAKT assay and demonstrates broad activity in breast, ovarian, lung, and prostate cancer models. Methods: A Phase I dose escalation study using a 3+3 design was initiated in patients (pts) with solid tumors. GDC-0941 was given on d1, followed by 1 wk washout to study single-dose PK and PD markers. GDC-0941 was then administered qd on a 3 wk on, 1 wk off, schedule. Steady-state PK and PD were evaluated after 1 wk of continuous dosing. A separate concurrent dose-escalation arm with bid dosing was initiated after the third qd cohort. Results: Nineteen pts have been enrolled in 5 successive dose-escalation cohorts in the qd arm with dose levels up to 80 mg daily. Seven pts were enrolled in 2 cohorts in the bid arm at total daily doses of 60 and 80 mg. The most frequently reported drug-related AEs were Grade 1/2 nausea, fatigue, diarrhea, peripheral edema, and dysgeusia; no drug related grade >3 events have been reported. PK data suggest dose-proportional increases in Cmax and AUC. Potential signs of anti-tumor activity have been observed with a soft tissue sarcoma pt on-study for >176 days with stable disease (30 mg qd), an ovarian cancer pt with an on-study 2.8-fold decrease in CA-125 response to normal levels (30 mg bid) and a pt with endometrial cancer with a decrease in tumor FDG-PET uptake (80 mg qd). Conclusions: GDC-0941 is generally well-tolerated with potential signs of anti-tumor activity. Preliminary PK data suggest dose-proportional increases in exposure over the dose levels evaluated. Dose-escalation on both the qd and bid schedules continues with updated data to be presented.

[Table: see text]

A phase I study evaluating the pharmacokinetics (PK) and pharmacodynamics (PD) of the oral pan-phosphoinositide-3 kinase (PI3K) inhibitor GDC-0941

3538

Background: The PI3K-PTEN-AKT signaling pathway is deregulated in a wide variety of cancers. GDC-0941 is a potent and selective oral inhibitor of class I PI3K and demonstrates activity in a broad range of preclinical models (breast, ovarian, lung, and prostate). Methods: Patients (pts) with histologically confirmed advanced solid tumors and ECOG PS 0–1 were treated with GDC-0941 using a 3+3 escalation design at a single institution. Treatment was a single dose with 1wk washout, followed by GDC-0941 qd on a 3wk on, 1wk off schedule. Objectives were to determine MTD and DLT, evaluate PD endpoints in surrogate (pAKT in platelet rich plasma) and tumor (pAKT and pS6 in paired tumor biopsies and FDG uptake via PET imaging) tissues, and describe anti-tumor activity. Results: Thirteen patients have been enrolled in 4 successive cohorts (15–60 mg qd). GDC-0941 was generally well-tolerated with no drug related Grade 3 or 4 AEs or DLTs to date. Grade 1 diarrhea, nausea, dysgeusia, peripheral sensory neuropathy, dry mouth, thrombocytopenia, and increased aspartate aminotransferase have been observed. Preliminary PK data suggest dose-proportional increases in fasting mean Cmax and AUC. Preliminary PD data show decreased levels of pAKT in platelet rich plasma correlated with GDC-0941 plasma concentrations. GDC-0941 effects on FDG-PET imaging is being assessed, with 1 patient with HER2+ metastatic breast cancer showing a reduction in FDG uptake and improvement of a chest wall lesion (dose level 60 mg qd). Evaluation of PI3K pathway modulation from paired tumor biopsies is underway. Conclusions: GDC-0941 is generally well tolerated when administered qd at doses associated with inhibition of pAKT in surrogate tissues. Evidence of PD activity in tumor tissue has also been observed. Dose-escalation continues and updated PK/PD data will be presented.

[Table: see text]

Formation of an intermediate compound with a B12H12 cluster: experimental and theoretical studies on magnesium borohydride Mg(BH4)2

Experimental and theoretical studies on Mg(BH4)2 were carried out from the viewpoint of the formation of the intermediate compound MgB12H12 with B12H12 cluster. The full dehydriding and partial rehydriding reactions of Mg(BH4)2 occurred according to the following multistep reaction: Mg(BH4)2 -->1/6MgB12H12 + 5/6MgH2 + 13/6H2 <--> MgH2 + 2B + 3H2 <--> Mg + 2B + 4H2. The dehydriding reaction of Mg(BH4)2 starts at approximately 520 K, and 14.4 mass% of hydrogen is released upon heating to 800 K. Furthermore, 6.1 mass% of hydrogen can be rehydrided through the formation of MgB12H12. The mechanism for the formation of MgB12H12 under the present rehydriding condition is also discussed.

CD25high T cells with a prolonged survival inhibit development of diabetes

The goal of this study is to examine a novel hypothesis that the progression of diabetes is partially due to the weakened survival of CD25high T cells, and prolonging survival of CD25high T cells inhibits the development of diabetes. Since CD28 co-stimulation is essential for the survival of CD4+CD25high T cells, we determined whether CD28-upregulated translationally controlled tumor protein (TCTP) prolongs the survival of CD4+CD25high regulatory T cells (Tregs) by a transgenic approach. The TCTP transgene prevents Tregs from undergoing apoptosis induced by interleukin-2 withdrawal-, dexamethasone-, cyclophosphamide-, and anti-Fas treatment in vitro. In addition, transgenic Tregs express higher levels of FOXP3 than wild-type counterparts and maintain suppressive activity, suggesting that TCTP promotes Tregs escape from thymic negative selection, and that prolonged survival does not attenuate Treg suppression. Moreover, TCTP transgenic Tregs inhibit the development of autoimmune diabetes due to increased survival of suppressive Tregs and decreased expression of pancreatic TNF-alpha. Promoting the survival of CD25high T cells leads to prolonged survival of Tregs but not activated CD25+ non-Treg T cells. Thus, we propose a new model of "two phase survival" for Tregs. Our results suggest that modulation of Treg survival can be developed as a new therapy for autoimmune diseases.

First Report of Syringa oblata and S. reticulata Leafroll Disease in China

Syringa oblata is an important ornamental tree widely grown in China. In September of 2008, S. oblata plants exhibiting symptoms of leafroll and yellowing were found in a garden on the Northwest A&F University campus. Samples were collected from this site. Total DNA was extracted from 0.5 g of phloem tissue from leaf midribs and stems of each sample. DNA samples were analyzed with a nested PCR assay using phytoplasma 16S rDNA universal primers R16mF2/R16mR1 followed by specific primers R16F2n/R16R2 (1), which amplified a 1,452- and 1,246-bp product, respectively. We tested all 30 lilac samples, 20 of which had symptoms of leafroll and yellowing. These produced the expected 1,452- and 1,246-bp PCR products In contrast, the remaining 10 samples from symptomless trees yielded no PCR products. We also surveyed another lilac variety (Syringa reticulata), which is widely grown on the campus, and tested 50 samples with the above method. Again, 1.4- and 1.2-kb PCR products were amplified from all 30 trees displaying leafroll and yellowing symptoms, but not from the other 20 samples from symptomless trees. A comparative analysis of sequences derived from the two hosts showed that the phytoplasmas infecting them were most similar (>99%) to paulownia witches'-broom (PaWB) phytoplasma (GenBank Accession No. EF199937). Restriction fragment length polymorphism (RFLP) analysis of the nested 1.2-kb 16S rDNA products with endonucleases AluI and MseI indicated that all symptomatic plants were infected by the phytoplasmas belonging to aster yellow group (16SrI) subgroup D (16SrI-D) PaWB phytoplasma (2). 16S rDNA sequence comparisons and RFLP analysis of the cloned 16S rDNA from S. oblata (GenBank Accession No. FJ445224) and S. reticulate (GenBank Accession No. FJ445225) indicated that the phytoplasmas infecting them were nearly identical (99.8% identity). To our knowledge, this is the first report of the presence of the phytoplasma associated with a leafroll disease of S. oblata and S. reticulata in China. References: (1) D. E. Gundersen and I.-M. Lee. Phytopathol. Mediterr. 35:144, 1996. (2) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998.

Efficacy and safety of ginsenoside-Rd for acute ischaemic stroke: a randomized, double-blind, placebo-controlled, phase II multicenter trial

BACKGROUND AND PURPOSE

Ginsenoside-Rd is a selective competitive Ca2+ receptor antagonist. A phase II randomized, double-blind, placebo-controlled, multicenter study was conducted to examine the efficacy and safety of ginsenoside-Rd in patients with acute ischaemic stroke.

METHODS

A total of 199 patients were randomized equally to receive a 14-day infusion of placebo (group B), ginsenoside-Rd 10 mg (group A) or ginsenoside-Rd 20 mg (group C). Primary end-points were National Institutes of Health Stroke Scale (NIHSS) scores at 15 days. Secondary end-points were NIHSS scores and the Barthel Index at 8 days, the Barthel Index and the modified Rankin scale at 15 days and 90 days. The safety end-points included serious and non-serious adverse events, laboratory values and vital signs. Analysis was by intention to treat.

RESULTS

For the primary study outcome, there is significant difference amongst the three groups at 15 days in NIHSS scores (P = 0.0003). Comparing group A with B and group B with C, the difference in the mean for NIHSS was significant in statistics (P = 0.0004, P = 0.0009 respectively). This is no significant difference between group A and C (P = 0.9640). For the secondary study outcome, ginsenoside-Rd did not improve neurological functioning. Incidence of serious and non-serious adverse events was similar amongst the three groups.

CONCLUSIONS

Ginsenoside-Rd may be of some benefit in acute ischaemic stroke.

Physical activity and colon cancer prevention: a meta-analysis

Although an inverse association between physical activity and risk of colon cancer is well established, a formal estimate of the magnitude of this risk reduction that includes recent studies is not available. This analysis examines the association by sex and study design, restricting analyses to studies where data for colon cancer alone were available. The authors reviewed published studies through June 2008 examining the association between physical activity and risk of colon cancer. Heterogeneity and publication bias were evaluated and random effects models used to estimate relative risks (RR). Differences by sex and study design were evaluated. A total of 52 studies were included. An inverse association between physical activity and colon cancer was found with an overall relative risk (RR) of 0.76 (95% confidence interval (CI): 0.72, 0.81). For men, the RR was 0.76 (95% CI: 0.71, 0.82); for women, this was little different, (RR=0.79, 95% CI: 0.71, 0.88). The findings from case-control studies were stronger (RR=0.69, 95% CI: 0.65, 0.74) than for cohort studies (RR=0.83, 95% CI: 0.78, 0.88). This study confirms previous studies reporting an inverse association between physical activity and colon cancer in both men and women, and provides quantitative estimates of the inverse association.

Protection mechanisms against Abeta42 aggregation

It is widely accepted that Abeta42 aggregation is a central event in the pathogenesis of Alzheimer's disease. Abeta42 oligomers and fibrils cause the breakdown of neural circuits, neuronal death and eventually dementia. There are a number of physiological molecules that can protect Abeta42 from aggregation. Promoting such protective molecules and mechanisms against Abeta42 aggregation may be a novel direction in AD drug discovery. One of the most striking protective molecules is none other than Abeta40, which inhibits Abeta42 aggregation in a specific and dosage dependent manner. Abeta40 is a critical, built-in mechanism against Abeta42 aggregation. A number of other molecules and mechanisms also inhibit Abeta42 aggregation, such as heat shock proteins, L-PGDS, heme and methionine oxidation. The relevance of these protective mechanisms to AD pathogenesis and intervention is discussed.

Multi-modality imaging of N-methyl-N-nitrosourea-induced mammary tumors by MRI and small animal PET

Abstract #6008

Background: We evaluated the use of high resolution Magnetic Resonance Imaging (MRI) and small animal Positron Emission Tomography (PET) imaging in assessing tumor proliferation and response to therapy in N-methyl-N-nitrosourea (MNU)-induced mammary tumors.&#x2028; Materials and Methods: The study comprised of 30 untreated MNU rats, 6 Targretin-treated MNU rats, and 6 Vorozole-treated MNU rats. Rats received a baseline imaging session when they developed their first palpable mammary tumor and were subsequently randomized into a control group or a treatment group with either Targretin (220mg/kg in the diet) or Vorozole (1.25mg/kg body weight by gavage). Treatment lasted for 8 weeks following the baseline imaging session. Each rat was imaged for 10-weeks at 2-week intervals with a) FDG to assess the metabolic state of tumors, b) MRI to monitor tumor volume, and c) [18F]ISO-1, a Sigma-2 radiolabeled ligand, to assess the proliferative status of MNU-induced tumors. Static images (10-minute) were obtained 60-minutes post-injection of FDG and [18F]ISO-1. In untreated tumors, a minimum of 40 PET outcome measures were assessed for their ability to predict changes in MRI-derived volume measurements between consecutive imaging sessions. In addition, regression analysis was performed to assess the correlation (R) between the measures. In treated tumors, the time-course of changes in PET outcome measures relative to baseline was evaluated to assess the efficacy of Targretin and Vorozole, in particular in characterizing short-term response (initial 2-weeks) and response to treatment withdrawal (weeks 8-10).&#x2028; Results: An index characterizing a MRI-normalized [18F]ISO-1 uptake significantly correlated (R=0.7, P&lt;0.0003) with changes in tumor volume between consecutive imaging sessions in untreated tumors. In contrast, there was no correlation between FDG outcome measures and changes in tumor volume. Targretin had the strongest short-term efficacy with a reduction in tumor load, on average, by as much as 60% compared with Vorozole's 20% reduction in tumor load. We observed higher rate of tumor resurgence in rats treated with Vorozole compared with Targretin, suggesting a residual effect of Targretin. In general, PET outcome measures of both FDG and [18F]ISO-1 delineated short-term response to treatment and non-responding tumors. [18F]ISO-1 was more sensitive than FDG in capturing tumor growth following treatment withdrawal at week 8.&#x2028; Conclusion: MRI and small animal PET provide a platform to assess MNU-induced tumor proliferation and the efficacy of therapeutic interventions non-invasively, as demonstrated in this work.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6008.