Leukocyte telomere length and hTERT genetic polymorphism rs2735940 influence the renal cell carcinoma clinical outcome.

Aim: Analysis of the genetic hTERT-1327 C>T (rs2735940) influence on leukocyte telomere length (LTL) and tumor development, progression and overall survival in renal cell carcinoma (RCC) patients. Materials & methods: Using leukocyte DNA of RCC patients and healthy individuals, LTL measurement and allelic discrimination of rs2735940 was performed by real-time PCR. Results: RCC patients showed shorter LTL than healthy individuals and LTL increased with clinical stage. CC+TC genotypes healthy carriers' presented shorter LTL. However, no statistical association between the different genotypes and RCC risk. Nevertheless, CC homozygous presented a reduced time to disease progression and a lower overall survival. The use of hTERT-1327 single nucleotide polymorphism information increased the capacity to predict risk for RCC progression. Conclusion: In fact, in healthy individuals, hTERT-1327 CC+TC genotypes were associated with shorter LTL, and this single nucleotide polymorphism was associated with time to disease progression, being a promising potential prognosis biomarker to be used in the future.

MicroRNAs and altered metabolism of clear cell renal cell carcinoma: Potential role as aerobic glycolysis biomarkers.

BACKGROUND: Warburg Effect is a metabolic switch that occurs in most of cancer cells but its advantages are not fully understood. This switch is known to happen in renal cell carcinoma (RCC), which is the most common solid cancer of the adult kidney. RCC carcinogenesis is related to pVHL loss and Hypoxia Inducible Factor (HIF) activation, ultimately leading to the activation of several genes related to glycolysis. MicroRNAs (miRNAs) regulate gene expression at a post-transcriptional level and are also deregulated in several cancers, including RCC. SCOPE OF REVIEW: This review focuses in the miRNAs that direct target enzymes involved in glycolysis and that are deregulated in several cancers. It also reviews the possible application of miRNAs in the improvement of clinical patients' management. MAJOR CONCLUSIONS: Several miRNAs that direct target enzymes involved in glycolysis are downregulated in cancer, strongly influencing the Warburg Effect. Due to this strong influence, FDG-PET can possibly benefit from measurement of these miRNAs. Restoring their levels can also bring an improvement to the current therapies. GENERAL SIGNIFICANCE: Despite being known for almost a hundred years, the Warburg Effect is not fully understood. MiRNAs are now known to be intrinsically connected with this effect and present an opportunity to understand it. They also open a new door to improve current diagnosis and prognosis tests as well as to complement current therapies. This is urgent for cancers like RCC, mostly due to the lack of an efficient screening test for early relapse detection and follow-up and the development of resistance to current therapies.

Cytomegalovirus infection in patients who underwent allogeneic hematopoietic stem cell transplantation in Portugal: a five-year retrospective review.

Cytomegalovirus (CMV) infection is 1 of the leading causes of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (aHSCT), mainly within the first 100 days after transplantation. We aimed to characterize CMV infection in a cohort of 305 patients with different malignancies undergoing aHSCT at the Portuguese Institute of Oncology of Porto between January 2008 and December 2012. In total, 184 patients (60.3%) developed CMV infection, mainly viral reactivations rather than primary infections (96.2% versus 3.8%, respectively). The majority of patients (166 of 184) developed CMV infection ≤100 days after transplantation, with median time to infection of 29 days (range, 0 to 1285) and median duration of infection of 10 days (range, 2 to 372). Multivariate analysis revealed that CMV infection was increased in donor (D)-/recipient (R)+ and D+/R+ (odds ratio [OR], 10.5; 95% confidence interval [CI], 4.35 to 25.4; P < .001) and in patients with mismatched or unrelated donors (OR, 2.54; 95% CI, 1.34 to 4.80; P = .004). Cox regression model showed that the risk of death was significantly increased in patients >38 years old (OR, 1.89; 95% CI, 1.14 to 3.12; P = .0137), who underwent transplantation with peripheral blood (OR, 3.02; 95% CI, 1.33 to 6.86; P = .008), with mismatched or unrelated donor (OR, 2.16; 95% CI, 1.48 to 3.13; P < .001), and who developed CMV infection (OR, 1.76; 95% CI, 1.07 to 2.90; P = .025). Moreover, patients who developed CMV infection had a significantly reduced median post-transplantation survival (16 versus 36 months; P = .002).

Influence of peripheral whole-blood microRNA-7 and microRNA-221 high expression levels on the acquisition of castration-resistant prostate cancer: evidences from in vitro and in vivo studies.

Prostate cancer (PC) is the more frequently diagnosed neoplasia in men in developed countries. The evolution of PC to castration-resistant prostate cancer (CRPC) represents real problems of clinical management, in consequence to the limited therapeutic options. MicroRNAs (miRNAs) are small noncoding RNAs that play an important role in gene expression and function regulation. The increased evidence that miRNAs are involved in cancer development and progression has made them potential biomarkers for cancer diagnosis, prognosis, and aggressiveness. Our purpose was to identify a miRNA expression profile associated with the development of CRPC. We firstly observed a miRNA expression profile differentially expressed between the castration-resistant (CR) PC3 cell line and the hormone-sensitive LnCaP cell line, where miR-7, miR-221, and miR-222 were upregulated in PC3 (11.3-fold increase, P = 0.012; 11.3-fold increase, P = 0.002; 8.6-fold increase, P = 0.002, respectively). We also observed that the trend of miR-1233 expression levels was higher in PC3 (3.7-fold increase, P = 0.057). These miRNAs differentially expressed in vitro were studied in a peripheral whole-blood samples from PC patients. We observed that patients presenting an early CR acquisition (≤ 20 months) had higher expression levels of miR-7 and miR-221 (P = 0.034 and P = 0.036, respectively). Furthermore, we found that patients diagnosed with high-Gleason score tumors and presenting simultaneous higher miR-7 expression levels have a significant reduce time to CR compared with patients who present lower miR-7 expression levels (11 vs. 51 months, log-rank test P = 0.004). We also found that patients diagnosed with high-Gleason score tumors and higher expression levels of miR-221 have an early CRPC compared to patients with lower miR-221 expression levels (10 vs. 46 months, log-rank test P = 0.012). We observed a significantly lower overall survival in patients with higher peripheral whole-blood expression levels of miR-7 (28 vs. 116 months, log-rank test P = 0.001). Our results suggest that miR-7 and miR-221 peripheral whole-blood expression levels can be potential predictive biomarkers of CRPC development.

Higher circulating expression levels of miR-221 associated with poor overall survival in renal cell carcinoma patients.

The mechanisms involved in renal cell carcinoma (RCC) development and progression remain unclear, and new biomarkers for early detection, follow-up of the disease and prognosis are needed in routine practice to improve the diagnostic and/or prognostic accuracy. There is increasing evidence that microRNAs (miRNAs) are involved in cancer development and progression. The up-regulation of miR-221/222 has been described in several human cancers, and during RCC development, this up-regulation can modulate the metastatic process. Our purpose was to investigate the circulating expression levels of miR-221/222 as potential biomarkers for RCC detection and their influence in patients' overall survival. The circulating miR-221/222 was studied by relative quantification in 77 plasma samples. A follow-up study was undertaken to evaluate the overall survival. We observed that RCC patients presented higher circulating expression levels of miR-221 and miR-222 than healthy individuals (2(-ΔΔCt) = 2.8, P = 0.028; 2(-ΔΔCt) = 2.2, P = 0.044, respectively). The RCC patients with metastasis at diagnosis also presented higher circulating expression levels of miR-221 than patients with no metastasis (2(-ΔΔCt) = 10.9, P = 0.001). We also observed a significantly lower overall survival in patients with higher expression levels of miR-221 (48 vs 116 months, respectively; P = 0.024). Furthermore, multivariate Cox regression analysis using the tumour, nodes and metastasis stage (TNM stage); Fuhrman nuclear grade and age (≥60 years) as covariants demonstrated a higher risk of specific death by cancer in patients who presented higher expression levels of miR-221 (hazard ratio (HR) = 10.7, 95% confidence interval 1.33-85.65, P = 0.026). The concordance (c) index showed that the definition of profiles that contain information regarding tumour characteristics associated with circulating miR-221 expression information presents an increased capacity to predict the risk of death by RCC (c index model 1, 0.800 vs model 2, 0.961). Our results, which identified the plasma miR-221/222 at variable levels during RCC development, suggest that these miRNAs may have a potential as noninvasive biomarkers of RCC development.

Structural similarity based kriging for quantitative structure activity and property relationship modeling.

Structurally similar molecules tend to have similar properties, i.e. closer molecules in the molecular space are more likely to yield similar property values while distant molecules are more likely to yield different values. Based on this principle, we propose the use of a new method that takes into account the high dimensionality of the molecular space, predicting chemical, physical, or biological properties based on the most similar compounds with measured properties. This methodology uses ordinary kriging coupled with three different molecular similarity approaches (based on molecular descriptors, fingerprints, and atom matching) which creates an interpolation map over the molecular space that is capable of predicting properties/activities for diverse chemical data sets. The proposed method was tested in two data sets of diverse chemical compounds collected from the literature and preprocessed. One of the data sets contained dihydrofolate reductase inhibition activity data, and the second molecules for which aqueous solubility was known. The overall predictive results using kriging for both data sets comply with the results obtained in the literature using typical QSPR/QSAR approaches. However, the procedure did not involve any type of descriptor selection or even minimal information about each problem, suggesting that this approach is directly applicable to a large spectrum of problems in QSAR/QSPR. Furthermore, the predictive results improve significantly with the similarity threshold between the training and testing compounds, allowing the definition of a confidence threshold of similarity and error estimation for each case inferred. The use of kriging for interpolation over the molecular metric space is independent of the training data set size, and no reparametrizations are necessary when more compounds are added or removed from the set, and increasing the size of the database will consequentially improve the quality of the estimations. Finally it is shown that this model can be used for checking the consistency of measured data and for guiding an extension of the training set by determining the regions of the molecular space for which new experimental measurements could be used to maximize the model's predictive performance.

Noncontiguous atom matching structural similarity function.

Measuring similarity between molecules is a fundamental problem in cheminformatics. Given that similar molecules tend to have similar physical, chemical, and biological properties, the notion of molecular similarity plays an important role in the exploration of molecular data sets, query-retrieval in molecular databases, and in structure-property/activity modeling. Various methods to define structural similarity between molecules are available in the literature, but so far none has been used with consistent and reliable results for all situations. We propose a new similarity method based on atom alignment for the analysis of structural similarity between molecules. This method is based on the comparison of the bonding profiles of atoms on comparable molecules, including features that are seldom found in other structural or graph matching approaches like chirality or double bond stereoisomerism. The similarity measure is then defined on the annotated molecular graph, based on an iterative directed graph similarity procedure and optimal atom alignment between atoms using a pairwise matching algorithm. With the proposed approach the similarities detected are more intuitively understood because similar atoms in the molecules are explicitly shown. This noncontiguous atom matching structural similarity method (NAMS) was tested and compared with one of the most widely used similarity methods (fingerprint-based similarity) using three difficult data sets with different characteristics. Despite having a higher computational cost, the method performed well being able to distinguish either different or very similar hydrocarbons that were indistinguishable using a fingerprint-based approach. NAMS also verified the similarity principle using a data set of structurally similar steroids with differences in the binding affinity to the corticosteroid binding globulin receptor by showing that pairs of steroids with a high degree of similarity (>80%) tend to have smaller differences in the absolute value of binding activity. Using a highly diverse set of compounds with information about the monoamine oxidase inhibition level, the method was also able to recover a significantly higher average fraction of active compounds when the seed is active for different cutoff threshold values of similarity. Particularly, for the cutoff threshold values of 86%, 93%, and 96.5%, NAMS was able to recover a fraction of actives of 0.57, 0.63, and 0.83, respectively, while the fingerprint-based approach was able to recover a fraction of actives of 0.41, 0.40, and 0.39, respectively. NAMS is made available freely for the whole community in a simple Web based tool as well as the Python source code at http://nams.lasige.di.fc.ul.pt/.

Influence of survivin (BIRC5) and caspase-9 (CASP9) functional polymorphisms in renal cell carcinoma development: a study in a southern European population.

Renal cell carcinoma (RCC) is the most common cancer of the adult kidney and its incidence and mortality has increase in the last 20 years. The disruption of cellular death is one the mechanism involved in cancer development. This process is precise regulated by apoptotic and anti-apoptotic molecules. Survivin (BIRC5) is a member of the inhibitor of apoptosis protein family and has the ability to inhibit the activation of the pro-apoptotic caspase-9 (CASP9). Thus BIRC5 and CASP9 functional polymorphisms might modulate the apoptosis and consequently RCC development. Our purpose was to investigate the potential role of BIRC5-31G/C and CASP9+83C/T functional polymorphisms in the risk for the development of RCC and metastatic disease. We studied the BIRC5-31G/C and CASP9+83C/T functional polymorphisms by PCR-RFLP and allelic discrimination using the 7300 real-time polymerase chain reaction system, respectively, in 178 RCC patients and in 305 healthy individuals. Regarding the BIRC5-31G/C polymorphism, there is a trend to an overrepresentation of CC genotype in RCC group compared with normal controls (aOR, 1.94; P=0.053). We observed, after gender stratification and age-adjustment, that BIRC5-31CC and CASP9+83CT/TT genotypes were associated with an increased risk for RCC development in the female group of our southern European study population (aOR=3.85; P=0.019; aOR=2.98; P=0.028; respectively). Concerning the waiting time for onset of metastatic disease, we observed that BIRC5-31CC homozygous developed metastasis 8 years earlier than the G carriers using a Cox proportional hazard model with gender as covariate (HR=4.9, P=0.038, P bootstrap=0.009). The Cox regression proportional hazard model was validated using bootstrap statistic with 1,000 samples of the same number of patients as the original dataset. Our results suggest that individual differences influence the susceptibility to RCC and tumor behavior. This genetic profile may help to define higher risk groups that would benefit from individualized chemoprevention strategies and therapies.

A Bayesian approach to in silico blood-brain barrier penetration modeling.

The human blood-brain barrier (BBB) is a membrane that protects the central nervous system (CNS) by restricting the passage of solutes. The development of any new drug must take into account its existence whether for designing new molecules that target components of the CNS or, on the other hand, to find new substances that should not penetrate the barrier. Several studies in the literature have attempted to predict BBB penetration, so far with limited success and few, if any, application to real world drug discovery and development programs. Part of the reason is due to the fact that only about 2% of small molecules can cross the BBB, and the available data sets are not representative of that reality, being generally biased with an over-representation of molecules that show an ability to permeate the BBB (BBB positives). To circumvent this limitation, the current study aims to devise and use a new approach based on Bayesian statistics, coupled with state-of-the-art machine learning methods to produce a robust model capable of being applied in real-world drug research scenarios. The data set used, gathered from the literature, totals 1970 curated molecules, one of the largest for similar studies. Random Forests and Support Vector Machines were tested in various configurations against several chemical descriptor set combinations. Models were tested in a 5-fold cross-validation process, and the best one tested over an independent validation set. The best fitted model produced an overall accuracy of 95%, with a mean square contingency coefficient (ϕ) of 0.74, and showing an overall capacity for predicting BBB positives of 83% and 96% for determining BBB negatives. This model was adapted into a Web based tool made available for the whole community at http://b3pp.lasige.di.fc.ul.pt.

Mitochondrial Sirtuin-3 (SIRT3) Prevents Doxorubicin-Induced Dilated Cardiomyopathy by Modulating Protein Acetylation and Oxidative Stress.

BACKGROUND: High doses of doxorubicin put cancer patients at risk for developing dilated cardiomyopathy. Previously, we showed that doxorubicin treatment decreases SIRT3 (sirtuin 3), the main mitochondrial deacetylase and increases protein acetylation in rat cardiomyocytes. Here, we hypothesize that SIRT3 expression can attenuate doxorubicin induced dilated cardiomyopathy in vivo by preventing the acetylation of mitochondrial proteins. METHODS: Nontransgenic, M3-SIRT3 (truncated SIRT3; short isoform), and M1-SIRT3 (full-length SIRT3; mitochondrial localized) transgenic mice were treated with doxorubicin for 4 weeks (8 mg/kg body weight per week). Echocardiography was performed to assess cardiac structure and function and validated by immunohistochemistry and immunofluorescence (n=4-10). Mass spectrometry was performed on cardiac mitochondrial peptides in saline (n=6) and doxorubicin (n=5) treated hearts. Validation was performed in doxorubicin treated primary rat and human induced stem cell derived cardiomyocytes transduced with adenoviruses for M3-SIRT3 and M1-SIRT3 and deacetylase deficient mutants (n=4-10). RESULTS: Echocardiography revealed that M3-SIRT3 transgenic mice were partially resistant to doxorubicin induced changes to cardiac structure and function whereas M1-SIRT3 expression prevented cardiac remodeling and dysfunction. In doxorubicin hearts, 37 unique acetylation sites on mitochondrial proteins were altered. Pathway analysis revealed these proteins are involved in energy production, fatty acid metabolism, and oxidative stress resistance. Increased M1-SIRT3 expression in primary rat and human cardiomyocytes attenuated doxorubicin-induced superoxide formation, whereas deacetylase deficient mutants were unable to prevent oxidative stress. CONCLUSIONS: Doxorubicin reduced SIRT3 expression and markedly affected the cardiac mitochondrial acetylome. Increased M1-SIRT3 expression in vivo prevented doxorubicin-induced cardiac dysfunction, suggesting that SIRT3 could be a potential therapeutic target for mitigating doxorubicin-induced dilated cardiomyopathy.

Cancer Cells' Metabolism Dynamics in Renal Cell Carcinoma Patients' Outcome: Influence of GLUT-1-Related hsa-miR-144 and hsa-miR-186.

The cancer cells' metabolism is altered due to deregulation of key proteins, including glucose transporter 1 (GLUT-1), whose mRNA levels are influenced by microRNAs (miRNAs). Renal cell carcinoma (RCC) is the most common and lethal neoplasia in the adult kidney, mostly due to the lack of accurate diagnosis and follow-up biomarkers. Being a metabolic associated cancer, this study aimed to understand the hsa-miR-144-5p and hsa-miR-186-3p's potential as biomarkers of clear cell RCC (ccRCC), establishing their role in its glycolysis status. Using three ccRCC lines, the intra- and extracellular levels of both miRNAs, GLUT-1's mRNA expression and protein levels were assessed. Glucose consumption and lactate production were evaluated as glycolysis markers. A decrease of intracellular levels of these miRNAs and increase of their excretion was observed, associated with an increase of GLUT-1's levels and glycolysis' markers. Through a liquid biopsy approach, we found that RCC patients present higher plasmatic levels of hsa-miR-186-3p than healthy individuals. The Hsa-miR144-5p's higher levels were associated with early clinical stages. When patients were stratified according to miRNAs plasmatic levels, low plasmatic levels of hsa-miR-144-5p and high plasmatic levels of hsa-miR-186-3p (high-risk group) showed the worst overall survival. Thus, circulating levels of these miRNAs may be potential biomarkers of ccRCC prognosis.

Migration as a Determinant in the Development of Children Emotional and Behavior Problems: A Quantitative Study for Lisbon Region, Portugal.

The role of migration as a determinant in child mental health has been demonstrated in a number of studies. However, results are not always consistent, and the research continues to be scarce, especially in Portugal. We examined the association between sociodemographic profiles and the chance for the development of emotional and behavioral difficulties in a group of 420 children, immigrant (n = 217) and born in Portugal to Portuguese born parents (n = 203). We used a structured questionnaire to obtain sociodemographic information and the Strength and Difficulties Questionnaire (SDQ). Descriptive statistics were used to characterize children and their families; variables were compared between groups using the Chi-squared, Fisher's Exact Test, or the Mann-Whitney U test and logistic regression was used to analyze the association between socio-demographic factors and emotional and behavioral difficulties. Results showed a pattern of social and mental health inequalities with immigrant children at a disadvantage: they are more often part of families with low income and where parents had low skilled jobs. Internalizing behaviors are more frequent in immigrants than in children born in Portugal to Portuguese-born parents (p = 0.001) whereas a high total SDQ difficulties score (p = 0.039) and externalizing behaviors were more frequent in 1st generation immigrant children (p = 0.009). A low family income (aOR 4.5; 95% CI: 1.43-13.95), low parental education level (aOR 2.5; 95% CI: 1.11-5.16), and being a first-generation immigrant child (aOR 2.2; 95% CI: 1.06-4.76) increased significantly the chance of developing emotional and behavioral difficulties. This study contributes to the identification of children vulnerable to mental health problems who can benefit from monitoring, early detection and preventive interventions in order to mitigate possible negative outcomes in the future.

Genetic polymorphism in EGF is associated with prostate cancer aggressiveness and progression-free interval in androgen blockade-treated patients.

PURPOSE: Most prostate cancer patients develop resistance to androgen deprivation treatment, resulting in hormone resistance. Epidermal growth factor (EGF) activates several pro-oncogenic intracellular pathways inducing proliferation, differentiation, and tumorigenesis in epithelial cells. The EGF-EGF receptor pathway seems to be especially relevant in hormone-resistant prostate cancer stage. A single nucleotide polymorphism G>A in +61 locus of EGF gene has been described, in which A homozygous carriers express significantly less EGF protein compared with G allele carriers. Our purpose was to investigate the potential prognostic and predictive role of EGF functional genetic variant +61 G>A in prostate cancer patients submitted to androgen blockade therapy (ABT). EXPERIMENTAL DESIGN: We conducted a case-control study in prostate cancer patients treated with ABT (n = 123) and in healthy controls without evidence of cancer (n = 152). Cumulatively, a follow-up study (median follow-up, 37 months) was undertaken to evaluate response to ABT therapy in prostate cancer patients. EGF +61 G>A genotypes were detected by PCR-RFLP. RESULTS: We found increased risk in G carriers, after age-adjusted regression analysis, for being diagnosed with Gleason > or =7 and with metastatic disease compared with control group (CG; age-adjusted odds ratio, 3.37, P = 0.004 and age-adjusted odds ratio, 2.61, P = 0.043, respectively). Kaplan-Meier survival analysis and log-rank test showed an influence of EGF +61 G>A polymorphism in time to relapse during ABT (P = 0.018). CONCLUSIONS: EGF functional polymorphism may contribute to earlier relapse in ABT patients, supporting the involvement of EGF as an alternative pathway in hormone-resistant prostatic tumors. Furthermore, our results lend support to EGF-EGF receptor pathway as an additional therapeutic target during hormonal treatment.

Dysregulated expression of microRNA-150 in human papillomavirus-induced lesions of K14-HPV16 transgenic mice.

AIMS: High-risk human papillomavirus (HPV) infection is one of the major causes of infection-related cancers worldwide. MicroRNAs (miRNAs) are a family of non-coding RNAs (ncRNAs), whose dysregulated levels may cause an aberrant expression of genes involved in oncogenic pathways and consequently lead to cancer development. This is the case of the miRNA-150 (miR-150), whose expression in HPV-induced lesions remains unclear and the present work aims to clarify it. We employed K14-HPV16 mice, which express the early genes of HPV16 in basal keratinocytes, leading to the development of hyperplastic and dysplastic skin lesions and squamous cell carcinomas, and are a representative model of HPV-induced cancers. MAIN METHODS: In order to evaluate the expression of miR-150 in HPV-induced lesions, we performed qPCR in wild-type mice (HPV-/-) and in skin lesions of K14-HPV16 transgenic mice (HPV+/-). Matched skin samples were analyzed histologically. KEY FINDINGS: 24-26weeks-old HPV+/- mice showed diffuse epidermal hyperplasia and focal dysplasia in a hyperplastic background (31.8% incidence), but 28-30weeks-old HPV+/- mice presented higher incidence of dysplasia (100.0%). MiR-150 was upregulated in HPV+/- mice when compared with HPV-/- mice (p<0.001). MiR-150 was also overexpressed in diffuse dysplastic lesions when compared with hyperplastic lesions (p=0.005). SIGNIFICANCE: The present results suggest that miR-150 is overexpressed in HPV-induced lesions in this model and its expression seems to increase with lesion progression, along the process of multi-step carcinogenesis.

Circulating biomarkers in renal cell carcinoma: the link between microRNAs and extracellular vesicles, where are we now?

Renal cell carcinoma (RCC) is a lethal urological cancer, with incidence and mortality rates increasing by 2-3% per decade. The lack of standard screening tests contributes to the fact that one-third of patients are diagnosed with locally invasive or metastatic disease. Moreover, 20-40% of RCC patients submitted to surgical nephrectomy will develop metastasis. MicroRNAs (miRNAs) are small non-coding RNAs responsible for gene regulation at a post-transcriptional level. It is accepted that they are deregulated in cancer and can influence tumor development. Thus, miRNAs are promising RCC biomarkers, since they can be detected using non-invasive methods. They are highly stable and easier to quantify in circulating biofluids. The elevated miRNA stability in circulating samples may be the consequence of their capacity to circulate inside of extracellular microvesicles (EMVs), for example, the exosomes. The EMVs are bilayered membrane vesicles secreted by all cell types. They can be released in the interstitial space or into circulating biofluids, which allows the travelling, binding and entrance of these vesicles in receptor cells. This type of cell communication can shuttle bioactive molecules between cells, allowing the horizontal transference of genetic material. In this review, we focus on circulating miRNAs (miR-210, miR-1233, miR-221, miR-15a, miR-451, miR-508, miR-378) in the biofluids of RCC patients and attempt to establish the diagnostic and prognostic accuracy, their synergic effects, and the pathways involved in RCC biology.

Combined Influence of EGF+61G>A and TGFB+869T>C Functional Polymorphisms in Renal Cell Carcinoma Progression and Overall Survival: The Link to Plasma Circulating MiR-7 and MiR-221/222 Expression.

The epidermal growth factor (EGF) is responsible for the activation of intracellular signal transducers that act on cell-cycle progression, cell motility, angiogenesis and inhibition of apoptosis. However, cells can block these effects activating opposite signaling pathways, such as the transforming growth factor beta 1 (TGFß1) pathway. Thus changes in expression levels of EGF and TGFB1 in renal cells might modulate the renal cell carcinoma (RCC) development, in consequence of changes in regulatory elements of signaling networks such as the microRNAs (miRNAs). Our purpose was to investigate the synergic role of EGF+61G>A and TGFB1+869T>C polymorphisms in RCC development. Genetic polymorphisms were studied by allelic discrimination using real-time PCR in 133 RCC patients vs. 443 healthy individuals. The circulating EGF/EGFR-MAPK-related miR-7, miR-221 and miR-222 expression was analyzed by a quantitative real-time PCR in plasma from 22 RCC patients vs. 27 healthy individuals. The intermediate/high genetic proliferation profile patients carriers present a significantly reduced time-to-progression and a higher risk of an early relapse compared with the low genetic proliferation profile carriers (HR = 8.8, P = 0.038) with impact in a lower overall survival (Log rank test, P = 0.047). The RCC patients presented higher circulating expression levels of miR-7 than healthy individuals (6.1-fold increase, P<0.001). Moreover, the intermediate/high genetic proliferation profile carriers present an increase in expression levels of miR-7, miR-221 and miR-222 during the RCC development and this increase is not observed in low genetic proliferation profile (P<0.001, P = 0.004, P<0.001, respectively). The stimulus to angiogenesis, cell-cycle progression and tumoral cells invasion, through activation of EGFR/MAPK signaling pathway in intermediate/high proliferation profile carriers is associated with an early disease progression, resulting in a poor overall survival. We also demonstrated that the intermediate/high proliferation profile is an unfavorable prognostic factor of RCC and miR-7, miR-221 and miR-222 expressions may be useful phenotype biomarkers of EGFR/MAPK activation.

Random forests for feature selection in QSPR Models - an application for predicting standard enthalpy of formation of hydrocarbons.

BACKGROUND: One of the main topics in the development of quantitative structure-property relationship (QSPR) predictive models is the identification of the subset of variables that represent the structure of a molecule and which are predictors for a given property. There are several automated feature selection methods, ranging from backward, forward or stepwise procedures, to further elaborated methodologies such as evolutionary programming. The problem lies in selecting the minimum subset of descriptors that can predict a certain property with a good performance, computationally efficient and in a more robust way, since the presence of irrelevant or redundant features can cause poor generalization capacity. In this paper an alternative selection method, based on Random Forests to determine the variable importance is proposed in the context of QSPR regression problems, with an application to a manually curated dataset for predicting standard enthalpy of formation. The subsequent predictive models are trained with support vector machines introducing the variables sequentially from a ranked list based on the variable importance. RESULTS: The model generalizes well even with a high dimensional dataset and in the presence of highly correlated variables. The feature selection step was shown to yield lower prediction errors with RMSE values 23% lower than without feature selection, albeit using only 6% of the total number of variables (89 from the original 1485). The proposed approach further compared favourably with other feature selection methods and dimension reduction of the feature space. The predictive model was selected using a 10-fold cross validation procedure and, after selection, it was validated with an independent set to assess its performance when applied to new data and the results were similar to the ones obtained for the training set, supporting the robustness of the proposed approach. CONCLUSIONS: The proposed methodology seemingly improves the prediction performance of standard enthalpy of formation of hydrocarbons using a limited set of molecular descriptors, providing faster and more cost-effective calculation of descriptors by reducing their numbers, and providing a better understanding of the underlying relationship between the molecular structure represented by descriptors and the property of interest.

Renal cell carcinoma development and miRNAs: a possible link to the EGFR pathway.

Renal cell carcinoma (RCC) is the most common solid cancer of the adult kidney and the majority of RCC cases are detected accidentally. This reality and the nonexistence of a standard screening test contribute to the fact that one third of patients are diagnosed with local invasive disease or metastatic disease. miRNAs are a family of small ncRNAs that regulate gene expression and have been identified as key regulators in many biological processes including cell development, differentiation, apoptosis and proliferation. The EGF receptor signaling pathway is usually deregulated in cancer and it is suggested to have an important role in RCC. Further studies are needed to characterize deregulation of this pathway during RCC development. In this review we highlight some potential miRNAs that could be involved in the modulation of the EGF receptor pathway and consequently in RCC development.

Improvement of a predictive model of castration-resistant prostate cancer: functional genetic variants in TGFß1 signaling pathway modulation.

Prostate cancer (PC) is the most frequently diagnosed cancer in men. The acquisition of castration-resistant (CR) phenotype is associated with the activation of signaling pathways mediated by growth factors. The TGFß1 and its receptors have an important role in tumor progression, being the pro-apoptotic function modulated by the expression of TGFBR2. A single nucleotide polymorphism -875 G > A in TGFBR2 gene has been described, which may influence the expression levels of the receptor. Our purpose was to investigate the potential role of TGFBR2-875G>A in PC risk and in the response to androgen deprivation therapy (ADT). TGFBR2-875G>A polymorphism was studied by allelic discrimination using real-time polymerase chain reaction (PCR) in 891 patients with PC and 874 controls. A follow-up study was undertaken to evaluate response to ADT. The TGFBR2 and SMAD7 mRNA expression were analyzed by a quantitative real-time PCR. We found that TGFBR2-875GG homozygous patients present lower expression levels of TGFBR2 mRNA (AA/AG: 2(-ΔΔCT) =1.5, P=0.016). GG genotype was also associated with higher Gleason grade (OR=1.51, P=0.019) and increased risk of an early relapse after ADT (HR=1.47, P=0.024). The concordance (c) index analysis showed that the definition of profiles that contains information regarding tumor characteristics associated with genetic information present an increased capacity to predict the risk for CR development (c-index model 1: 0.683 vs model 2: 0.736 vs model 3: 0.746 vs model 4: 0.759). The TGFBR2-875G>A contribution to an early relapse in ADT patients, due to changes in mRNA expression, supports the involvement of TGFß1 pathway in CRPC. Furthermore, according to our results, we hypothesize the potential benefits of the association of genetic information in predictive models of CR development.

EGFR signaling pathway and related-miRNAs in age-related diseases: the example of miR-221 and miR-222.

Presently, neurodegenerative diseases and cancer are the most clinically problematic age-related diseases worldwide. Although being distinct disorders, their developments share common cellular mechanisms. Oncogenesis and neurodegeneration arise from the deregulation of signaling pathways, as a consequence of the resulting imbalance in cellular homeostasis. The epidermal growth factor receptor (EGFR) belongs to an important cellular signaling pathway, which regulates proliferation, differentiation, cell cycle and migration. As transcriptional targets of EGFR, the microRNAs-221/222 (miR-221/222) are important expression regulators. Dysfunctions in their networks are associated with cellular disruptions. The transcriptional activation of these microRNAs (miRNAs) seems to be involved in cell cycle, apoptosis, metastization, and in the acquisition of resistance to therapies. The up-regulation of miR-221/222 is associated with increased expression levels of matrix metalloproteinases (MMPs) and repression of cell cycle inhibitors, which are key molecules in oncogenesis and neurodegeneration processes. The interaction loop between proliferative signaling pathways and miRNA expression could reveal new targets for controlling the molecular behavior of age-related diseases.