Combined effects of retinoic acid and histone deacetylase inhibitors on human neuroblastoma SH-SY5Y cells

8 pages, 7 figures.-- El pdf del artículo es la versión post-print.All-trans retinoic acid (RA) causes differentiation of neuroblastoma cells, and retinoids have been used in clinical trials in children with advanced neuroblastoma. Combination of RA with histone deacetylase inhibitors (HDACi) could result in improved antitumorigenic activity. We have examined the effect of the HDACi trichostatin A (TSA), sodium butyrate, and suberoylanilide hydroxamic acid (SAHA), alone and in combination with RA in human neuroblastoma SH-SY5Y cells. At concentrations that cause sustained increase of histone H3 acetylation, HDACi produced extensive apoptotic cell death as shown by flow cytometry analysis and induction of poly(ADP-ribose) polymerase proteolysis. HDACi inhibited SH-SY5Y cell growth at a much larger extent than RA. This compound did not cause apoptosis and did not further increase HDACi-mediated cell death. In contrast, both types of drugs cooperated to inhibit cell growth, although synergistic effects were not found. In surviving cells, HDACi repressed cyclin D1 expression and increased the cyclin kinase inhibitors (CKI) p21(Waf1/Cip1) and p27(Kip1). Cyclin D1 was not affected by RA, but this retinoid also increased CKI levels. Induction of p21(Waf1/Cip1) and p27(Kip1) by HDACi was further enhanced in the presence of RA. This effect seems to be at least partially due to transcriptional stimulation of CKI gene expression because both types of drugs cooperated to increase CKI mRNA levels and to activate the CKI promoters in transient transfection assays. These results show the strong antitumorigenic effects of HDACi in neuroblastoma cells and reinforce the idea that combination therapy could be useful to inhibit tumor growth.BFU2004 03465 from Ministerio de Ciencia y Tecnología, RD06/0020/0036 from Fondo de Investigaciones Sanitarias, and by Fundación La Caixa. Maxy De los Santos is a fellow of Fundación Carolina.Peer reviewe

Native rodent species are unlikely sources of infection for Leishmania (Viannia) braziliensis along the Transoceanic Highway in Madre de Dios, Peru.

An estimated 2.3 million disability-adjusted life years are lost globally from leishmaniasis. In Peru's Amazon region, the department of Madre de Dios (MDD) rises above the rest of the country in terms of the annual incidence rates of human leishmaniasis. Leishmania (Viannia) braziliensis is the species most frequently responsible for the form of disease that results in tissue destruction of the nose and mouth. However, essentially nothing is known regarding the reservoirs of this vector-borne, zoonotic parasite in MDD. Wild rodents have been suspected, or proven, to be reservoirs of several Leishmania spp. in various ecosystems and countries. Additionally, people who live or work in forested terrain, especially those who are not regionally local and whose immune systems are thus naïve to the parasite, are at most risk for contracting L. (V.) braziliensis. Hence, the objective of this study was to collect tissues from wild rodents captured at several study sites along the Amazonian segment of the newly constructed Transoceanic Highway and to use molecular laboratory techniques to analyze samples for the presence of Leishmania parasites. Liver tissues were tested via polymerase chain reaction from a total of 217 rodents; bone marrow and skin biopsies (ear and tail) were also tested from a subset of these same animals. The most numerous rodent species captured and tested were Oligoryzomys microtis (40.7%), Hylaeamys perenensis (15.7%), and Proechimys spp. (12%). All samples were negative for Leishmania, implying that although incidental infections may occur, these abundant rodent species are unlikely to serve as primary reservoirs of L. (V.) braziliensis along the Transoceanic Highway in MDD. Therefore, although these rodent species may persist and even thrive in moderately altered landscapes, we did not find any evidence to suggest they pose a risk for L. (V.) braziliensis transmission to human inhabitants in this highly prevalent region

Outbreak of Cutaneous Leishmaniasis in Peruvian Military Personnel Undertaking Training Activities in the Amazon Basin, 2010

ArticleMilitary personnel deployed to the Amazon Basin are at high risk for cutaneous leishmaniasis (CL). We responded to an outbreak among Peruvian Army personnel returning from short-term training in the Amazon, conducting active case detection, lesion sample collection, and risk factor assessment. The attack rate was 25% (76/303); the incubation period was 2–36 weeks (median = 8). Most cases had one lesion (66%), primarily ulcerative (49%), and in the legs (57%). Real-time polymerase chain reaction (PCR) identified Leishmania (Viannia) braziliensis (59/61 = 97%) and L. (V.) guyanensis (2/61 = 3%). Being male (risk ratio [RR] = 4.01; P = 0.034), not wearing long-sleeve clothes (RR = 1.71; P = 0.005), and sleeping in open rooms (RR = 1.80; P = 0.009) were associated with CL. Sodium stibogluconate therapy had a 41% cure rate, less than previously reported in Peru (70%; P < 0.001). After emphasizing pre-deployment education and other basic prevention measures, trainees in the following year had lower incidence (1/278 = 0.4%; P < 0.001). Basic prevention can reduce CL risk in deployed militaries.The outbreak response was supported by the Peruvian Army Health Command COSALE and the Peruvian Ministry of Health through the General Epidemiology Directorate and the Health Directorate II, south Lima, and the. In addition, partial support was provided by grants CO497_11_L1 and CO466_11_L1 of the Global Emerging Infections Surveillance and Response System (AFHSC/GEIS) of the U.S. Department of Defense and the training grant 2D43 TW007393 awarded to the U.S. Naval Medical Research Unit No. 6 (NAMRU-6) by the Fogarty International Center of the National Institutes of Health (FIC/NIH). This study is part of the dissertation of Marianela Ore for a Masters in Epidemiological Research offered jointly by the Universidad Peruana Cayetano Heredia (UPCH) and NAMRU-6

Interacción de ligandos de receptores nucleares con los inhibidores de desacetilasas de histonas sobre la proliferación y diferenciación de células de neuroblastoma y adenocarcinoma mamario humanos

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid. Facultad de Medicina. Departamento de Bioquímica. Fecha de lectura: 27 de Febrero de 200

Identificación de una nueva proteína en Leishmania (Viannia) peruviana

El análisis de la secuencia nucleotídica y aminoacídica de un clon de la biblioteca de expresión en fago λgt11 de Leishmania (Viannia) peruviana, estableció identidad parcial con los genes de las proteínas acídicas ribosomales P2 de Leishmania (Leishmania) infantum. Este hallazgo unido a ciertos dominios geonómicos conservados, sugeridos de la comparación de 14 secuencias de otras proteínas P1 eucarióticas, confirman que la secuencia del inserto de clon codifica la proteína acídica ribosomal P1 de L. (V.) peruviana denominada LpP1. Este es el primer reporte sobre este tipo de proteína en el género Leishmania

Anti-estrogenic actions of histone deacetylase inhibitors in MCF-7 breast cancer cells

Anti-estrogens are the current endocrine therapy of choice in the treatment of estrogen receptor (ER)-positive breast cancers. Histone deacetylase inhibitors (HDACi) also constitute a promising treatment for therapy, and combination of anti-estrogens with HDACi may improve efficacy while reducing side effects. We have examined the effect of the HDACi sodium butyrate and suberoylanilide hydroxamic acid (SAHA), alone and in combination with 17β-estradiol (E 2) and the pure anti-estrogen ICI 182.780 (ICI) in human MCF-7 breast cancer cells. HDACi caused a sustained increase of histone H3 acetylation and caused cell death as shown by flow cytometry analysis. In surviving cells, both inhibitors were even stronger than ICI in depleting cyclin D1 levels, inducing expression of the cyclin kinase inhibitor p21 Waf1/Cip1 blocking phosphorylation of the retinoblastoma protein, or inhibiting cell growth. No additive effects of ICI with either butyrate or SAHA were found. In addition, these drugs were able to antagonize the effects of E 2 on expression of cell cycle proteins, cell growth, and transcription of ER-dependent genes. The anti-estrogenic effects of HDACi appear to be related to a strong downregulation of the expression of ERα that appears to be secondary to both transcriptional and post-transcriptional regulation. ERα phosphorylation is involved in estrogen signaling, and HDACi also prevented receptor phosphorylation in Ser-118 both in the absence and presence of ER ligands. These results provide further support for the use of deacetylase inhibitors as chemotherapeutic agents in the treatment of breast cancer tumors.This work was supported by grants BFU2004 03165 from the Ministerio de Educación y Ciencia, RD06/0020/0036 and PIO40682 from the Fondo de Investigaciones Sanitarias and from the EU Project CRESCENDO (FP6-018652). Maxy De los Santos was financed by a fellowship from Fundación Carolina

Histone deacetylase inhibitors regulate retinoic acid receptor beta expression in neuroblastoma cells by both transcriptional and posttranscriptional mechanisms

12 pages, 8 figures.The retinoic acid receptor beta (RARbeta) is a retinoic acid (RA)-inducible tumor suppressor, which plays an important role in the arrest of neuroblastoma cell growth. Using human neuroblastoma SH-SY5Y cells, we have examined the regulation of RARbeta expression by histone deacetylase inhibitors (HDACi), considered to be promising agents in anticancer therapy. Our results show that HDACi cooperated with RA to increase RARbeta mRNA levels and to activate the RARbeta2 promoter in transient transfection assays. Chromatin immunoprecipitation assays showed that the basal RARbeta2 promoter that contains the RA response element was refractory to acetylation by both HDACi and RA. In addition, HDACi caused a transient increase in acetylation of a downstream RARbeta2 region, even though global histones remain hyperacetylated after a prolonged treatment with the inhibitors. RA potentiated this response and maintained acetylation for a longer period. Despite the cooperation of RA with HDACi to increase transcription of the RARbeta gene, these inhibitors caused a paradoxical reduction of the cellular levels of the RARbeta protein in cells treated with the retinoid. This reduction is secondary to a change in the protein half-life that is decreased by the HDACi due to increased ubiquitin-independent proteasomal degradation. These results show that HDACi regulate expression of the tumor suppressor gene RARbeta by both transcriptional and posttranscriptional mechanisms and might then modulate sensitivity to the retinoid in neuroblastoma cells.This work was supported by BFU2004 03165 from the Ministerio de Educación y Ciencia, RD06/0020/0036 from the Fondo de Investigaciones Sanitarias, and from the European Union Project CRESCENDO (FP6-018652). M.D.l.S. was financed by a fellowship from Fundación Carolina.Peer reviewe

Genetic diversity and population structure of Leishmania (Viannia) braziliensis in the Peruvian jungle.

BackgroundHuman cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis is highly prevalent in the Peruvian jungle, where it affects military forces deployed to fight against drug trafficking and civilian people that migrate from the highland to the lowland jungle for economic activities such as mining, agriculture, construction, and chestnut harvest. We explored the genetic diversity and population structure of 124 L. (V.) braziliensis isolates collected from the highland (Junín, Cusco, and Ayacucho) and lowland Peruvian jungle (Loreto, Ucayali, and Madre de Dios). All samples were genotyped using Multilocus Microsatellite Typing (MLMT) of ten highly polymorphic markers.Principal findingsHigh polymorphism and genetic diversity were found in Peruvian isolates of L. (V.) braziliensis. Most markers are not in Hardy-Weinberg equilibrium; this deviation is most likely caused by local inbreeding, as shown by the positive FIS values. Linkage Disequilibrium in subpopulations was not strong, suggesting the reproduction was not strictly clonal. Likewise, for the first time, two genetic clusters of this parasite were determined, distributed in both areas of the Peruvian jungle, which suggested a possible recent colonization event of the highland jungle from the lowland jungle.ConclusionsL. (V.) braziliensis exhibits considerable genetic diversity with two different clusters in the Peruvian jungle. Migration analysis suggested a colonization event between geographical areas of distribution. Although no human migration was observed at the time of sampling, earlier displacement of humans, reservoirs, or vectors could have been responsible for the parasite spread in both regions