Leishmania amazonensis induces modulation of costimulatory and surface marker molecules in human macrophages.

Manipulation of costimulatory and surface molecules that shape the extent of immune responses by Leishmania is suggested as one of the mechanisms of evading the host's defences. The experiments reported here were designed to evaluate the expressions of CD11b, CD11c, CD14, CD18, CD54, CD80, CD86, CD206, MHC class II and TLR-2 (Toll-like receptor 2) in human macrophages infected with L. amazonensis. Phenotypic evaluation revealed a negative modulation in CD11b, CD11c, CD14, CD18, CD54 and MHC class II molecules, depending on the level of infection. The results showed that as early as 1 hour after infection no reduction in marker expression occurs, whereas after 24 hours, downregulation of these molecules was observed in macrophages. No significant changes were observed in the expressions of CD80, CD86, CD206 and TLR2. Evidence of the differential modulation of markers expression and that after parasite uptake no reduction in surface marker expression occurs indicates that parasite internalization is not involved in the phenomena of down-modulation.

Is there room for luminal-basal urothelial cell population quantification? / ¿Hay lugar para la cuantificación de la población de células uroteliales luminales basales?

PURPOSE: Three cell layers compose the urothelium: basal, intermediate and luminal ("umbrella cells") and different diseases might arise from different cell populations. The aim of this study is to analyze the quantification ability of such cell populations by using four different protocols. METHODS: Twenty male rats (Wistar) were randomized in four groups of five animals: scraping, enzymatic 30, 45 and 60minutes. The cells were isolated, analyzed by flow cytometer and data processed by BD FACSDIVA™ software. RESULTS: The urothelium was separated in two cell populations that are different in size and complexity. The group that showed more efficiency in cells dissociation and cells separation was enzymatic protocol 45minutes. CONCLUSIONS: Enzymatic protocol 45minutes was able to isolate urothelial cell populations and might be explored as potential prognostic tool, patient selection and therapeutic target in urothelial diseases. Future studies should validate the potential clinical application to the proposed rational of luminal-basal paradigm in the urothelial cancer as hope for individualized approach.

IGFBP7 participates in the reciprocal interaction between acute lymphoblastic leukemia and BM stromal cells and in leukemia resistance to asparaginase.

The interaction of acute lymphoblastic leukemia (ALL) blasts with bone marrow (BM) stromal cells (BMSCs) has a positive impact on ALL resistance to chemotherapy. We investigated the modulation of a series of putative asparaginase-resistance/sensitivity genes in B-precursor ALL cells upon coculture with BMSCs. Coculture with stromal cells resulted in increased insulin-like growth factor (IGF)-binding protein 7 (IGFBP7) expression by ALL cells. Assays with IGFBP7 knockdown ALL and stromal cell lines, or with addition of recombinant rIGFBP7 (rIGFBP7) to the culture medium, showed that IGFBP7 acts as a positive regulator of ALL and stromal cells growth, and significantly enhances in-vitro resistance of ALL to asparaginase. In these assays, IGFBP7 function occurred mainly in an insulin- and stromal-dependent manner. ALL cells were found to contribute substantially to extracellular IGFBP7 levels in the conditioned coculture medium. Diagnostic BM plasma from children with ALL had higher levels of IGFBP7 than controls. IGFBP7, in an insulin/IGF-dependent manner, enhanced asparagine synthetase expression and asparagine secretion by BMSCs, thus providing a stromal-dependent mechanism by which IGFBP7 protects ALL cells against asparaginase in this coculture system. Importantly, higher IGFBP7 mRNA levels were associated with lower leukemia-free survival (Cox regression model, P=0.003) in precursor B-cell Ph(-) ALL patients (n=147) treated with a contemporary polychemotherapy protocol.

The Wnt signaling pathway regulates Nalm-16 b-cell precursor acute lymphoblastic leukemic cell line survival and etoposide resistance.

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is the most common malignancy in children. The Wnt signaling pathway has been found to be extensively involved in cancer onset and progression but its role in BCP-ALL remains controversial. We evaluate the role of the Wnt pathway in maintenance of BCP-ALL cells and resistance to chemotherapy. Gene expression profile revealed that BCP-ALL cells are potentially sensitive to modulation of Wnt pathway. Nalm-16 and Nalm-6 cell lines displayed low levels of canonical activation, as reflected by the virtually complete absence of total beta-catenin in Nalm-6 and the beta-catenin cell membrane distribution in Nalm-16 cell line. Canonical activation with Wnt3a induced nuclear beta-catenin translocation and led to BCP-ALL cell death. Lithium chloride (LiCl) also induced a cytotoxic effect on leukemic cells. In contrast, both Wnt5a and Dkk-1 increased Nalm-16 cell survival. Also, Wnt3a enhanced the in vitro sensitivity of Nalm-16 to etoposide (VP-16) while treatment with canonical antagonists protected leukemic cells from chemotherapy-induced cell death. Overall, our results suggest that canonical activation of the Wnt pathway may exerts a tumor suppressive effect, thus its inhibition may support BCP-ALL cell survival.