Isolation and characterization of 20 polymorphic microsatellite loci in the migratory freshwater fish Leporinus obtusidens (Characiformes: Anostomidae) using 454 shotgun pyrosequencing

Twenty polymorphic microsatellite markers were developed for the Neotropical fish Leporinus obtusidens using a next generation sequencing approach and tested in two other characifomes species, Schizodon platae and Prochilodus lineatus. Microsatellite loci alleles in L. obtusidens ranged between 2 and 20 alleles per locus (mean = 5·7), with expected heterozygosity values ranging from 0·097 to 0·956 (mean = 0·578) and observed heterozygosity values ranging from 0·000 to 0·800 (mean = 0·400) in a sample of 20 specimens from the lower Paraná River (Argentina). Most of these markers will be a valuable tool for captive breeding and stocking programmes, as well as for analyses of population connectivity and genetic structure in this broadly distributed Neotropical migratory fish.

Study of the Complexes of the Ascorbic Acid-Iron(III) System

The blue complex of L-ascorbic acid with Fe3+ ions has been obtained and isolated. Various spectrographic and analytical techniques have been used to study this complex. A kinetic study was also carried out on L-ascorbic acid oxidation by Fe3+ by means of the stoppod flow technique for rapid processes.

Abstract P5-09-19: Progesterone receptor isoform A as a predictive marker of antiprogestin therapy in breast cancer: A tissue culture method to evaluate drug responsiveness

Two thirds of breast cancers express steroid hormone receptors and are susceptible to an endocrine therapy usually aimed to target the estrogen receptors (ER). There is however compelling evidence suggesting that progesterone receptors (PR) participate together with ER, modulating breast cancer growth. Based on our results obtained in an experimental breast cancer model in which antiprogestins induce complete regression of carcinomas with higher levels of PR isoform A (PR-A) than isoform B (PR-B), we propose that antiprogestins such as mifepristone (MFP) might be a possible therapeutic option for patients expressing high levels of PR-A. The goal of our study is to correlate the ratio of PR isoform expression, with the in vitro responsiveness of human breast cancer samples to MFP. Preliminary studies indicated that primary cultures of breast cancer samples overexpressing PR-A were responsive to MFP (10 nM) in vitro. However, since the rate of successful primary cultures was not encouraging (7%), we decided to develop a tissue culture assay to evaluate MFP responsiveness of breast cancer samples in vitro.

Forty five breast cancer samples obtained from the General Pacheco´s Hospital, Buenos Aires, were kept in culture medium at room temperature and in dry ice. The former were cut in slices of 100 μm using a tissue chopper usually used to slice mouse nervous tissue for short incubations, and were incubated on filters in the presence of growth medium (fetal calf serum 10%) with or without MFP (10 nM), for 48 hs at 37º C. The slices were then fixed, paraffin embedded, and processed for Ki-67 staining to evaluate proliferating cells. Frozen samples were processed for Western blotting and the ratio of both PR isoforms was determined in nuclear extracts. In 17/45 (38%) of the samples valuable information was obtained. This was related with the quality (size and amount of viable cells) of the sample. The number of Ki-67 positive cells over the total viable cells was evaluated by a pathologist (M. May) in at least six different control or MFP-treated slices. From nine cases in which the Ki-67 index in control slices doubled the value obtained in MFP-treated slices (p<0.05), 8 were samples in which PR-A was higher than PR-B. MFP increased (p<0.05) the Ki-67 index in one sample with higher levels of PR-B than PR-A. No significant differences were observed in the remaining cases (null, equimolar or higher levels of PR-B than PR-A). We still plan to increase the number of samples in our study. Our data suggest that the tissue culture method developed is much more efficient than the primary cultures to evaluate drug or hormone responsiveness in breast cancer tissue. The results obtained herein support the proposal of PR-A as a predictive marker of antiprogestin therapy in breast cancer patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-09-19.

Abstract PD1-7: Phosphatase and tensin homolog deleted from chromosome 10 (PTEN) evaluation in the NeoALTTO trial (BIG 01-06)

Introduction

Assessment of PTEN might be an important tool in identifying patients unlikely to derive substantial benefit from trastuzumab and lapatinib-based therapies. Current studies failed to demonstrate an unequivocal predictive role of PTEN in human epidermal growth factor receptor-2 (HER2)-positive breast cancer both in neo-adjuvant and adjuvant settings. Lack of standardization of PTEN status determination in formalin fixed paraffin embedded (FFPE) tissue samples together with the small datasets analyzed in previous studies may have contributed to conflicting PTEN results and high variability of PTEN loss rates reported (22%-64%).

Methods

In the present study we have conducted a preliminary analysis investigating the influence of the antibodies, scoring methods and cutoff criteria used, together with the impact of inter-observer variability on PTEN status determination. Core biopsies from 429 FFPE baseline samples from early-stage HER2-positive breast cancer patients prospectively collected in the neoALTTO trial were stained with two widely used anti-PTEN monoclonal antibodies (clone 6H2.1 from DAKO and clone 138G6 from Cell Signaling Technology-CST). Two different pathologists independently scored the slides using the H-score system. Two different cut-off criteria were used to define PTEN loss of expression: H-score < 50 and ≤10% positive staining (any level of intensity).

Results

Out of 429 processed samples, 363 and 369 were evaluable for observer 1 (CST and DAKO, respectively) and 367 were evaluable for observer 2, with an average missing rate of 15%. A strong linear correlation was observed between CST and DAKO antibodies for both observers (R2 > 0.7). After setting a cutoff for PTEN loss, the observed discordance rate was below 10%, with the number of discordant cases ranging from 28 to 33 (depending on the cut-off criteria and observer). Inter-observer correlation was strong with both antibodies (R2 = 0.8). Based on the cutoff criteria and antibodies used, inter-observer discordance rates ranged between 6% and 10%; the lowest rate observed at ≤10% cutoff threshold with CST antibody. PTEN was classified as “loss” in 23%, 19%, 16%, and 13% of cases by observer 1 and in 32%, 29%, 24%, 19% of cases by observer 2 using DAKO H-score<50, CST H-score<50, DAKO≤10%, and CST≤10% criteria, respectively.

Conclusion

Our preliminary analysis showed high inter-antibody and inter-observer concordant rates for PTEN status determination by IHC. However, the lack of a standardized definition of PTEN cutoff thresholds for defining negativity and positivity generated loss call rates ranging from 13% to 32% within the same dataset. Correlative analyses with pCR and PIK3CA status are ongoing to determine the impact of PTEN expression and its variability in predicting response to single-agent or dual HER2 targeting.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD1-7.

The influence of dietary locust bean gum and live yeast on some digestive immunological parameters of piglets experimentally challenged with Escherichia coli

Gums and yeast cells are natural mannose-rich products that can be used as subtracts for adhesion of gram-negative bacteria. The aim of the study was to investigate the role of dietary locust bean gum (LBG; Salmosan, ITPSA, Spain) or live yeast (Saccharomyces cerevisiae Sc47; Actisaf, Lesaffre, France) as immunological enhancers of the intestinal function of piglets. Treatments included a noninfected group fed with a control diet and 4 other groups orally challenged with 1x10(8) cfu of Escherichia coli K88. The challenged groups were fed the control or the control diet supplemented with colistin, LBG, or yeast. Twenty-five Landrace × Duroc piglets weaned at 4 wk were used. The animals were group housed, challenged on day 14, and euthanized 2 d later. Blood, bile, ileum, and mesenteric lymph node (MLN) samples were obtained for analysis of C-reactive protein (CRP), secretory immunoglobulin A (sIgA), and Toll-like receptors 2 (TLR2) and 4 (TLR4). Challenge increased the level of CRP of piglets fed the control diet, but this did not happen in the piglets fed the supplemented diets (P < 0.001). Challenge upregulated TLR2 in MLN and TLR4 in ileum and MLN (P < 0.05). This was prevented by yeast supplementation for the TLR2 in MLN and TLR4 in ileum. Pigs fed colistin and LBG diets showed intermediate but nonsignificant responses. In conclusion, the results suggest that colistin, live yeast, and LBG reduce the levels of CRP in blood of piglets challenged with E. coli, and yeast reduces the expression of Toll-like receptors in the intestine.

Sex peptide of Drosophila melanogaster males is a global regulator of reproductive processes in females

Seminal fluid proteins (Sfps) alter female behaviour and physiology and can mediate sexual conflict. In Drosophila melanogaster, a single Sfp, the sex peptide (SP), triggers remarkable post-mating responses in females, including altered fecundity, feeding, immunity and sexual receptivity. These effects can favour the evolutionary interests of males while generating costs in females. We tested the hypothesis that SP is an upstream master-regulator able to induce diverse phenotypes through efficient induction of widespread transcriptional changes in females. We profiled mRNA responses to SP in adult female abdomen (Abd) and head+thorax (HT) tissues using microarrays at 3 and 6 h following mating. SP elicited a rich, subtle signature of temporally and spatially controlled mRNAs. There were significant alterations to genes linked to egg development, early embryogenesis, immunity, nutrient sensing, behaviour and, unexpectedly, phototransduction. There was substantially more variation in the direction of differential expression across time points in the HT versus Abd. The results support the idea that SP is an important regulator of gene expression in females. The expression of many genes in one sex can therefore be under the influence of a regulator expressed in the other. This could influence the extent of sexual conflict both within and between loci.

Neutrophil to lymphocyte ratio (NLR) as an indicator of poor prognosis in stage IV non-small cell lung cancer

BACKGROUND

Neutrophil to lymphocyte ratio (NLR), an index of systemic inflammation, has been associated with worse survival for many types of cancer. The aim of this study is to investigate the clinical significance of the blood NLR as a prognostic factor in non-small cell lung cancer (NSCLC) patients.

METHODS AND PATIENTS

Stage IV NSCLC patients diagnosed in our institution between April 2004 and March 2009 were retrospectively reviewed. Potential prognostic factors such as histology, gender, performance status, response to chemotherapy and NLR were analyzed. NLR was assessed baseline and during chemotherapy treatment. Overall survival (OS) and progression free survival (PFS) were calculated by the Kaplan-Meier method.

RESULTS

A total of 171 patients were included in the study and 60 patients (35.1 %) presented a NLR ≥ 5. Median survival for the entire cohort was 9.3 months. We found that patients with undifferentiated carcinoma and patients with NLR ≥ 5 had a worse survival. Median PFS of patients with NLR <5 was 5.62 months and in patients with NLR ≥ 5 was 3.25 months (p = 0.098), and OS was 11.1 versus 5.6 months for patients with NLR<5 and NLR ≥ 5, respectively (p = 0.017). During the chemotherapy treatment, patients who normalized NLR after one cycle presented better outcomes (OS 8.7 vs. 4.3 months, p = 0.001, for patients who normalized NLR and for patients who remained persistently elevated). After multivariate analysis, histology and NLR remained independent predictors of survival (p < 0.05).

CONCLUSION

In our analysis, elevated NLR is a predictor of shorter survival in patients with advanced NSCLC and the variation of NLR during the first cycle of treatment predicts survival. NLR is an easily measured, reproducible test that could be considered to be incorporated in the routine practice in NSCLC patients.

Exploratory analysis of activation of PTEN-PI3K pathway and downstream proteins in malignant pleural mesothelioma (MPM)

BACKGROUND

Malignant pleural mesothelioma (MPM) is a highly aggressive neoplasm with elevated AKT/mTOR activity. We aimed to identify the expression and phosphorylation status of PTEN, PI3K and downstream signaling in MPM.

PATIENTS AND METHODS

Thirty consecutive MPM patients were identified. Clinical data analyzed: sex, age, histology, performance status (PS), white blood count, and neutrophil-lymphocyte ratio (NLR). Paraffin-embedded biopsies were used for immunohistochemical analysis.

RESULTS

Overexpression of PTEN, pMAPK, mTOR, pAKT, 4E-BP1, p4E-BP1, eIF-4E, peIF-4E, p-S6 and FOXO3a in MPM was found in 90%, 100%, 93.3%, 80%, 100%, 43.3%, 96.7%, 100%, 63.3% and 100% of tumors respectively. There was a significant correlation between low pS6 protein expression and longer progression free survival (PFS: 7.9 vs 5.6 months; p = 0.04) and overall survival (OS: 23.4 vs 5.6 months; p = 0.05). Patients with concomitant low expression of pS6 and p4E-BP1 and overexpression of FOXO3a had significantly better prognosis (34.6 vs 1.9 months; p = 0.004). In multivariate analysis, histology and NLR were independent prognostic factors (p = 0.02 and p = 0.04 respectively), but pS6 only showed a trend (p = 0.8).

CONCLUSIONS

This study shows PI3K pathway and downstream proteins in MPM are frequently activated and provides prognostic information. The role of PI3K pathway is worth of prospective validation in future studies on MPM.