Xeroderma pigmentosum group D 751 polymorphism as a predictive factor in resected gastric cancer treated with chemo-radiotherapy

AIM: To evaluate the potential association of xeroderma pigmentosum group D (XPD) codon 751 variant with outcome after chemo-radiotherapy in patients with resected gastric cancer. METHODS: We used PCR-RFLP to evaluate the genetic XPD Lys751Gln polymorphisms in 44 patients with stage III (48%) and IV (20%) gastric cancer treated with surgery following radiation therapy plus 5-fluorouracil/ leucovorin based chemotherapy. RESULTS: Statistical analysis showed that 75% (12 of 16) of relapse patients showed Lys /Lys genotype more frequently (P = 0.042). The Lys polymorphism was an independent predictor of high-risk relapse-free survival from Cox analysis (HR: 3.07, 95% CI: 1.07-8.78, P = 0.036) and Kaplan-Meir test (P = 0.027, log-rank test). CONCLUSION: XPD Lys751Gln polymorphism may be an important marker in the prediction of clinical outcome to chemo-radiotherapy in resected gastric cancer patients

A gene signature of 8 genes could identify the risk of recurrence and progression in Dukes' B colon cancer patients

The benefit of postoperative adjuvant chemotherapy in patients with Dukes' B colorectal cancer is still uncertain and its routine use is not recommended. The five-year relapse rate is approximately 25-40% and the identification of patients at high risk of recurrence would represent an important strategy for the use of adjuvant chemotherapy. We retrospectively analyzed gene expression profiles in frozen tumor specimens from patients with Dukes' B colorectal cancer by using high density oligonucleotide microarrays. Our results show a subset of 48 genes differentially expressed with an associated probability <0.001 in the t-test. Another statistical procedure based on the Fisher criterion resulted in 11 genes able to separate both groups. We selected the 8 genes present in both subsets. The differential expression of five genes (CHD2, RPS5, ZNF148, BRI3 and MGC23401) in colon cancer progression was confirmed by real-time PCR in an independent set of patients of Dukes' B and C stages

New symmetrical quinazoline derivatives selectively induce apoptosis in human cancer cells

In the search of new symmetrical derivatives with anticancer activity, we have looked for novel compounds able to induce a selective proapoptotic mechanism in cancer cells. The potential antitumoral activity of several quinazoline derivatives was evaluated in vitro examining their cytotoxic effects against human breast, colon and bladder cancer cell lines. The IC(50) value of the compounds that showed cytotoxic activity was calculated. These compounds were tested for their ability to induce caspase-3 activation and nuclear chromatin degradation. Non-tumoral human cell lines were used to test the selectivity of the cytotoxic compounds against cancer cells. Several compounds showed no cytotoxicity in these cell lines. Finally, JRF12 (2,4-dibenzylaminoquinazoline) was chosen as the best candidate and its mechanism of action was studied in more detail. A time dependent evaluation of apoptosis was performed in the three cancer cell lines, followed by an evaluation of the cell cycle regulation involvement that showed a decrease of cells in G(1) phase and increase of cells in G(2) phase before cell death. 2,4-dibenzylaminoquinazoline treatment produces few changes in the expression of genes as evaluated by using oligonucleotide microarrays and Q-RT-PCR assays. In conclusion, 2,4-dibenzylaminoquinazoline is a promising anticancer drug showing cytostatic and apoptotic effects mainly in a transcription independent manner

Identification by Real-time PCR of 13 mature microRNAs differentially expressed in colorectal cancer and non-tumoral tissues

PURPOSE: Diffuse large B-cell lymphoma (DLBCL) heterogeneity has prompted investigations for new biomarkers that can accurately predict survival. A previously reported 6-gene model combined with the International Prognostic Index (IPI) could predict patients' outcome. However, even these predictors are not capable of unambiguously identifying outcome, suggesting that additional biomarkers might improve their predictive power. EXPERIMENTAL DESIGN: We studied expression of 11 microRNAs (miRNA) that had previously been reported to have variable expression in DLBCL tumors. We measured the expression of each miRNA by quantitative real-time PCR analyses in 176 samples from uniformly treated DLBCL patients and correlated the results to survival. RESULTS: In a univariate analysis, the expression of miR-18a correlated with overall survival (OS), whereas the expression of miR-181a and miR-222 correlated with progression-free survival (PFS). A multivariate Cox regression analysis including the IPI, the 6-gene model-derived mortality predictor score and expression of the miR-18a, miR-181a, and miR-222, revealed that all variables were independent predictors of survival except the expression of miR-222 for OS and the expression of miR-18a for PFS. CONCLUSION: The expression of specific miRNAs may be useful for DLBCL survival prediction and their role in the pathogenesis of this disease should be examined further

LMO2 expression reflects the different stages of blast maturation and genetic features in B-cell acute lymphoblastic leukemia and predicts clinical outcome

BACKGROUND: LMO2 is highly expressed at the most immature stages of lymphopoiesis. In T-lymphocytes, aberrant LMO2 expression beyond those stages leads to T-cell acute lymphoblastic leukemia, while in B cells LMO2 is also expressed in germinal center lymphocytes and diffuse large B-cell lymphomas, where it predicts better clinical outcome. The implication of LMO2 in B-cell acute lymphoblastic leukemia must still be explored. DESIGN AND METHODS: We measured LMO2 expression by real time RT-PCR in 247 acute lymphoblastic leukemia patient samples with cytogenetic data (144 of them also with survival and immunophenotypical data) and in normal hematopoietic and lymphoid cells. RESULTS: B-cell acute lymphoblastic leukemia cases expressed variable levels of LMO2 depending on immunophenotypical and cytogenetic features. Thus, the most immature subtype, pro-B cells, displayed three-fold higher LMO2 expression than pre-B cells, common-CD10+ or mature subtypes. Additionally, cases with TEL-AML1 or MLL rearrangements exhibited two-fold higher LMO2 expression compared to cases with BCR-ABL rearrangements or hyperdyploid karyotype. Clinically, high LMO2 expression correlated with better overall survival in adult patients (5-year survival rate 64.8% (42.5%-87.1%) vs. 25.8% (10.9%-40.7%), P= 0.001) and constituted a favorable independent prognostic factor in B-ALL with normal karyotype: 5-year survival rate 80.3% (66.4%-94.2%) vs. 63.0% (46.1%-79.9%) (P= 0.043). CONCLUSIONS: Our data indicate that LMO2 expression depends on the molecular features and the differentiation stage of B-cell acute lymphoblastic leukemia cells. Furthermore, assessment of LMO2 expression in adult patients with a normal karyotype, a group which lacks molecular prognostic factors, could be of clinical relevance

Involvement of miRNAs in the differentiation of human glioblastoma multiforme stem-like cells

Glioblastoma multiforme (GBM)-initiating cells (GICs) represent a tumor subpopulation with neural stem cell-like properties that is responsible for the development, progression and therapeutic resistance of human GBM. We have recently shown that blockade of NFκB pathway promotes terminal differentiation and senescence of GICs both in vitro and in vivo, indicating that induction of differentiation may be a potential therapeutic strategy for GBM. MicroRNAs have been implicated in the pathogenesis of GBM, but a high-throughput analysis of their role in GIC differentiation has not been reported. We have established human GIC cell lines that can be efficiently differentiated into cells expressing astrocytic and neuronal lineage markers. Using this in vitro system, a microarray-based high-throughput analysis to determine global expression changes of microRNAs during differentiation of GICs was performed. A number of changes in the levels of microRNAs were detected in differentiating GICs, including over-expression of hsa-miR-21, hsa-miR-29a, hsa-miR-29b, hsa-miR-221 and hsa-miR-222, and down-regulation of hsa-miR-93 and hsa-miR-106a. Functional studies showed that miR-21 over-expression in GICs induced comparable cell differentiation features and targeted SPRY1 mRNA, which encodes for a negative regulator of neural stem-cell differentiation. In addition, miR-221 and miR-222 inhibition in differentiated cells restored the expression of stem cell markers while reducing differentiation markers. Finally, miR-29a and miR-29b targeted MCL1 mRNA in GICs and increased apoptosis. Our study uncovers the microRNA dynamic expression changes occurring during differentiation of GICs, and identifies miR-21 and miR-221/222 as key regulators of this process

A cyclin-D1 interaction with BAX underlies its oncogenic role and potential as a therapeutic target in mantle cell lymphoma

The chromosomal translocation t(11;14)(q13;q32) leading to cyclin-D1 overexpression plays an essential role in the development of mantle cell lymphoma (MCL), an aggressive tumor that remains incurable with current treatment strategies. Cyclin-D1 has been postulated as an effective therapeutic target, but the evaluation of this target has been hampered by our incomplete understanding of its oncogenic functions and by the lack of valid MCL murine models. To address these issues, we generated a cyclin-D1-driven mouse model in which cyclin-D1 expression can be regulated externally. These mice developed cyclin-D1-expressing lymphomas capable of recapitulating features of human MCL. We found that cyclin-D1 inactivation was not sufficient to induce lymphoma regression in vivo; however, using a combination of in vitro and in vivo assays, we identified a novel prosurvival cyclin-D1 function in MCL cells. Specifically, we found that cyclin-D1, besides increasing cell proliferation through deregulation of the cell cycle at the G(1)-S transition, sequestrates the proapoptotic protein BAX in the cytoplasm, thereby favoring BCL2's antiapoptotic function. Accordingly, cyclin-D1 inhibition sensitized the lymphoma cells to apoptosis through BAX release. Thus, genetic or pharmacologic targeting of cyclin-D1 combined with a proapoptotic BH3 mimetic synergistically killed the cyclin-D1-expressing murine lymphomas, human MCL cell lines, and primary lymphoma cells. Our study identifies a role of cyclin-D1 in deregulating apoptosis in MCL cells, and highlights the potential benefit of simultaneously targeting cyclin-D1 and survival pathways in patients with MCL. This effective combination therapy also might be exploited in other cyclin-D1-expressing tumors

Long-term thermal sensitivity of Earth’s tropical forests

The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate

Análisis de la implicación de los microRNAs en la diferenciación de las células madre tumorales de glioblastoma multiforme

Los objetivos de esta tesis son: 1 - Establecimiento de cultivos de neuroesferas a partir de muestras quirúrgicas de pacientes con GBM. a) Análisis de su capacidad de autorrenovación. b) Estudio de su capacidad de desarrollo tumoral en un modelo de xenotransplante en ratones inmunodeficientes mediante inyección estereotáctica intracraneal. c) Análisis de su capacidad de diferenciación a los principales linajes neurales presentes en el SNC. 2 - Validación de un modelo de inducción de la diferenciación in vitro de las neuroesferas (o BTSCs) en presencia de factores de crecimiento. 3 - Análisis de la expresión global de miRNAs durante el proceso de diferenciación in vitro de las BTSCs de GBM mediante microarrays de miRNAs. 4 - Estudio de la implicación funcional de los miRNAs validados y seleccionados en la diferenciación in vitro de las BTSCs de GBM. a) Análisis del papel de estos miRNAs en la inducción de cambios de expresión de los marcadores de diferenciación neural. b) Estudio de otras posibles funciones de estos miRNAs en la biología de las BTSCs. 5 - Análisis de la expresión génica de las dianas potenciales de los miRNAs seleccionados y de su implicación en las rutas alteradas más relevantes de la diferenciación de las BTSCs. a) Examen de las rutas moleculares alteradas durante la diferenciación in vitro de las BTSCs. b) Búsqueda de posibles dianas de los miRNAs seleccionados entre los genes cuya expresión varía durante el proceso de diferenciación de las BTSCs