Molecular characterization of the region 7q22.1 in splenic marginal zone lymphomas

Splenic marginal zone lymphomas (SMZL) are an uncommon type of B-cell non-Hodgkin's lymphoma (NHL-B) in which no specific chromosomal translocations have been described. In contrast, the most frequent cytogenetic abnormality is the loss of the long arm of chromosome 7 (7q). Previous reports have located this loss in the 7q32 region. In order to better characterize the genomic imbalances in SMZL, molecular studies were carried out in 73 patients with SMZL. To gain insight into the mapping at 7q a tiling array was also used. The results confirmed the loss of 7q as the most frequent change. In addition, several abnormalities, including 4q22.1, 1q21.3-q22, 6q25.3, 20q13.33, 3q28, 2q23.3-q24.1 and 17p13, were also present. A loss of 7q22.1 at 99925039-101348479 bp was observed in half of the cases. The region of 7q22.1 has not previously been characterised in SMZL. Our results confirmed the presence of a new region of loss on chromosome 7 in these NHL.     

Protection against tuberculosis in Eurasian wild boar vaccinated with heat-inactivated Mycobacterium bovis

Tuberculosis (TB) caused by Mycobacterium bovis and closely related members of the Mycobacterium tuberculosis complex continues to affect humans and animals worldwide and its control requires vaccination of wildlife reservoir species such as Eurasian wild boar (Sus scrofa). Vaccination efforts for TB control in wildlife have been based primarily on oral live BCG formulations. However, this is the first report of the use of oral inactivated vaccines for controlling TB in wildlife. In this study, four groups of 5 wild boar each were vaccinated with inactivated M. bovis by the oral and intramuscular routes, vaccinated with oral BCG or left unvaccinated as controls. All groups were later challenged with a field strain of M. bovis. The results of the IFN-gamma response, serum antibody levels, M. bovis culture, TB lesion scores, and the expression of C3 and MUT genes were compared between these four groups. The results suggested that vaccination with heat-inactivated M. bovis or BCG protect wild boar from TB. These results also encouraged testing combinations of BCG and inactivated M. bovis to vaccinate wild boar against TB. Vaccine formulations using heat-inactivated M. bovis for TB control in wildlife would have the advantage of being environmentally safe and more stable under field conditions when compared to live BCG vaccines. The antibody response and MUT expression levels can help differentiating between vaccinated and infected wild boar and as correlates of protective response in vaccinated animals. These results suggest that vaccine studies in free-living wild boar are now possible to reveal the full potential of protecting against TB using oral M. bovis inactivated and BCG vaccines.     

Red and processed meat and colorectal cancer incidence: meta-analysis of prospective studies

Background

The evidence that red and processed meat influences colorectal carcinogenesis was judged convincing in the 2007 World Cancer Research Fund/American Institute of Cancer Research report. Since then, ten prospective studies have published new results. Here we update the evidence from prospective studies and explore whether there is a non-linear association of red and processed meats with colorectal cancer risk.

Methods and Findings

Relevant prospective studies were identified in PubMed until March 2011. For each study, relative risks and 95% confidence intervals (CI) were extracted and pooled with a random-effects model, weighting for the inverse of the variance, in highest versus lowest intake comparison, and dose-response meta-analyses. Red and processed meats intake was associated with increased colorectal cancer risk. The summary relative risk (RR) of colorectal cancer for the highest versus the lowest intake was 1.22 (95% CI  = 1.11−1.34) and the RR for every 100 g/day increase was 1.14 (95% CI  = 1.04−1.24). Non-linear dose-response meta-analyses revealed that colorectal cancer risk increases approximately linearly with increasing intake of red and processed meats up to approximately 140 g/day, where the curve approaches its plateau. The associations were similar for colon and rectal cancer risk. When analyzed separately, colorectal cancer risk was related to intake of fresh red meat (RR _{for 100 g/day increase}  = 1.17, 95% CI  = 1.05−1.31) and processed meat (RR _{for 50 g/day increase}  = 1.18, 95% CI  = 1.10−1.28). Similar results were observed for colon cancer, but for rectal cancer, no significant associations were observed.

Conclusions

High intake of red and processed meat is associated with significant increased risk of colorectal, colon and rectal cancers. The overall evidence of prospective studies supports limiting red and processed meat consumption as one of the dietary recommendations for the prevention of colorectal cancer.     

Antitumor activity of sorafenib in human cancer cell lines with acquired resistance to EGFR and VEGFR tyrosine kinase inhibitors

Treatment of non small cell lung cancer (NSCLC) and colorectal cancer (CRC) have substantially changed in the last years with the introduction of epidermal growth factor receptor (EGFR) inhibitors in the clinical practice. The understanding of mechanisms which regulate cells sensitivity to these drugs is necessary for their optimal use.An in vitro model of acquired resistance to two tyrosine kinase inhibitors (TKI) targeting the EGFR, erlotinib and gefitinib, and to a TKI targeting EGFR and VEGFR, vandetanib, was developed by continuously treating the human NSCLC cell line CALU-3 and the human CRC cell line HCT116 with escalating doses of each drug. MTT, western blot analysis, migration, invasion and anchorage-independent colony forming assays were conducted in vitro and experiments with established xenografts in athymic nude mice were performed in vivo in sensitive, wild type (WT) and TKI-resistant CALU-3 and HCT116 cell lines.As compared to WT CALU-3 and HCT116 human cancer cells, TKI-resistant cell lines showed a significant increase in the levels of activated, phosphorylated AKT, MAPK, and of survivin. Considering the role of RAS and RAF as downstream signals of both the EGFR and VEGFR pathways, we treated resistant cells with sorafenib, an inhibitor of C-RAF, B-RAF, c-KIT, FLT-3, RET, VEGFR-2, VEGFR-3, and PDGFR-β. Sorafenib reduced the activation of MEK and MAPK and caused an inhibition of cell proliferation, invasion, migration, anchorage-independent growth in vitro and of tumor growth in vivo of all TKI-resistant CALU-3 and HCT116 cell lines.These data suggest that resistance to EGFR inhibitors is predominantly driven by the RAS/RAF/MAPK pathway and can be overcame by treatment with sorafenib.     

Low digit ratio 2D:4D in alcohol dependent patients

The ratio of the lengths of the second and fourth finger (2D∶4D) has been described as reflecting the degree of prenatal androgen exposure in humans. 2D∶4D is smaller for males than females and is associated with traits such as left-handedness, physical aggression, attention-deficit-hyperactivity disorder and a genetic polymorphism of the androgen receptor. All of these traits are known to be correlated to the vulnerability for alcohol dependency. We therefore hypothesized low 2D∶4D in patients with alcohol dependency. In the present study on 131 patients suffering from alcohol dependency and 185 healthy volunteers, we found that alcohol dependent patients had smaller 2D∶4D ratios compared to controls with preserved sexual dimorphism but with reduced right-left differences. The detection of alcohol dependency based on 2D∶4D ratios was most accurate using the right hand of males (ROC-analysis: AUC 0.725, sensitivity 0.667, specificity 0.723). These findings provide novel insights into the role of prenatal androgen exposure in the development of alcohol dependency and for the use of 2D∶4D as a possible trait marker in identifying patients with alcohol dependency.     

Tyrosine phosphorylation of phosphoinositide-dependent kinase 1 by the insulin receptor is necessary for insulin metabolic signaling

In L6 myoblasts, insulin receptors with deletion of the C-terminal 43 amino acids (IR(Delta43)) exhibited normal autophosphorylation and IRS-1/2 tyrosine phosphorylation. The L6 cells expressing IR(Delta43) (L6(IRDelta43)) also showed no insulin effect on glucose uptake and glycogen synthase, accompanied by a >80% decrease in insulin induction of 3-phosphoinositide-dependent protein kinase 1 (PDK-1) activity and tyrosine phosphorylation and of protein kinase B (PKB) phosphorylation at Thr(308). Insulin induced the phosphatidylinositol 3 kinase-dependent coprecipitation of PDK-1 with wild-type IR (IR(WT)), but not IR(Delta43). Based on overlay blotting, PDK-1 directly bound IR(WT), but not IR(Delta43). Insulin-activated IR(WT), and not IR(Delta43), phosphorylated PDK-1 at tyrosines 9, 373, and 376. The IR C-terminal 43-amino-acid peptide (C-terminal peptide) inhibited in vitro PDK-1 tyrosine phosphorylation by the IR. Tyr-->Phe substitution prevented this inhibitory action. In the L6(hIR) cells, the C-terminal peptide coprecipitated with PDK-1 in an insulin-stimulated fashion. This peptide simultaneously impaired the insulin effect on PDK-1 coprecipitation with IR(WT), on PDK-1 tyrosine phosphorylation, on PKB phosphorylation at Thr(308), and on glucose uptake. Upon insulin exposure, PDK-1 membrane persistence was significantly reduced in L6(IRDelta43) compared to control cells. In L6 cells expressing IR(WT), the C-terminal peptide also impaired insulin-dependent PDK-1 membrane persistence. Thus, PDK-1 directly binds to the insulin receptor, followed by PDK-1 activation and insulin metabolic effects.     

Towards systematic identification of Plasmodium essential genes by transposon shuttle mutagenesis

After the deciphering of the genome sequences of several Plasmodium species, efforts must turn to elucidating gene function and identifying essential gene products. However, random approaches are lacking and gene targeting is inefficient in Plasmodium. Here, we established shuttle transposon mutagenesis in Plasmodium berghei. We constructed a mini-Tn5 derivative that can transpose into parasite genes cloned in Escherichia coli, providing an efficient means of generating knockout fragments. A 10⁴-fold increase in frequencies of double-crossover homologous recombination in the parasite using a new electroporation technology permits to reproducibly generate pools of distinct mutants after transfection with mini-Tn5-interrupted sequences. The procedure opens the way to the systematic identification of essential genes in Plasmodium.     

Analysis of NK cells and chemokine receptors in tumor infiltrating CD4 T lymphocytes in human renal carcinomas

Recent data suggest that chemokines and chemokine receptors mediate leukocyte recruitment of all components of the antitumor response. This study aimed to phenotypically characterize the immune lymphocyte infiltrate in human renal cell carcinomas (RCCs) and at the invasive margin (tumor–host interface) and to define the association of these findings with established prognostic indicators. Tumor infiltrating lymphocytes (TILs) were obtained from 24 patients with RCC undergoing radical nephrectomy. Peripheral blood cells from 37 patients were also obtained before surgery. Our findings are consistent with the preferential recruitment of CD4+ Th1-polarized effector memory cells that express CXCR3/CCR5. These cells were the main component of TILs and expressed as CXCR3, CCR5, CD45RO, and CD95. Natural killer (NK) cells were found in significantly higher proportions in TILs of RCCs than in peripheral blood lymphocytes (PBLs) or in other tumors studied (colorectal and breast cancers), where these cells were found in small proportions. No differences in nuclear grade or other studied parameters were observed between the TILs and the lymphocytes present at the invasive margin, which showed a similar composition. However, differences were found according to the tumor stage. First, significantly fewer NK cells were observed in PBLs from metastatic patients. Second, a significantly lower proportion of CCR5/CXCR3/CD4+ cells and a higher proportion of CCR4/CD4+ cells were observed in metastatic patients, suggesting that preferential Th1-polarization may gradually change during the progression of renal cancer cells. Finally, the frequency of CD25/CD4+ cells was higher in metastatic patients. Although the sample of patients with metastasis was small, the overall results suggest a change in composition of the TILs that may potentially confer a selective advantage for tumor growth and may account for the suppression of an effective cytotoxic response.     

Exposure to chronic stress downregulates corticosterone responses to acute stressors

We used captive European starlings (Sturnus vulgaris) to test whether corticosterone responses differed in birds held under normal laboratory conditions or conditions of chronic stress. Surprisingly, both basal corticosterone concentrations and corticosterone responses to acute stress were significantly reduced when birds were chronically stressed. To determine the mechanism underlying this reduced response, animals under both conditions were injected with lactated Ringer's solution (control), adrenocorticotropin (ACTH), arginine vasotocin (AVT), or dexamethasone (DEX). ACTH increased corticosterone concentrations above stress-induced levels in both cases, although maximum responses were lower in chronically stressed birds. AVT did not augment the corticosterone response under nonchronically stressed conditions, but it did under chronically stressed conditions. DEX reduced maximal corticosterone concentrations in both cases. Neither ovine nor rat corticotropin-releasing factor (CRF) altered normal stress responses. These data indicate that changes in responsiveness of the hypothalamic-pituitary-adrenal axis to ACTH and AVT serve to downregulate corticosterone responses during chronic stress. Furthermore, these data lead to the following hypothesis: ACTH output from the pituitary limits maximum corticosterone concentrations under normal conditions, but reduced AVT release from the hypothalamus regulates lower corticosterone concentrations under chronic stress conditions.