DIS3L2 knockdown impairs key oncogenic properties of colorectal cancer cells via the mTOR signaling pathway.

DIS3L2 degrades different types of RNAs in an exosome-independent manner including mRNAs and several types of non-coding RNAs. DIS3L2-mediated degradation is preceded by the addition of nontemplated uridines at the 3'end of its targets by the terminal uridylyl transferases 4 and 7. Most of the literature that concerns DIS3L2 characterizes its involvement in several RNA degradation pathways, however, there is some evidence that its dysregulated activity may contribute to cancer development. In the present study, we characterize the role of DIS3L2 in human colorectal cancer (CRC). Using the public RNA datasets from The Cancer Genome Atlas (TCGA), we found higher DIS3L2 mRNA levels in CRC tissues versus normal colonic samples as well as worse prognosis in patients with high DIS3L2 expression. In addition, our RNA deep-sequencing data revealed that knockdown (KD) of DIS3L2 induces a strong transcriptomic disturbance in SW480 CRC cells. Moreover, gene ontology (GO) analysis of significant upregulated transcripts displays enrichment in mRNAs encoding proteins involved in cell cycle regulation and cancer-related pathways, which guided us to evaluate which specific hallmarks of cancer are differentially regulated by DIS3L2. To do so, we employed four CRC cell lines (HCT116, SW480, Caco-2 and HT-29) differing in their mutational background and oncogenicity. We demonstrate that depletion of DIS3L2 results in reduced cell viability of highly oncogenic SW480 and HCT116 CRC cells, but had little or no impact in the more differentiated Caco-2 and HT-29 cells. Remarkably, the mTOR signaling pathway, crucial for cell survival and growth, is downregulated after DIS3L2 KD, whereas AZGP1, an mTOR pathway inhibitor, is upregulated. Furthermore, our results indicate that depletion of DIS3L2 disturbs metastasis-associated properties, such as cell migration and invasion, only in highly oncogenic CRC cells. Our work reveals for the first time a role for DIS3L2 in sustaining CRC cell proliferation and provides evidence that this ribonuclease is required to support the viability and invasive behavior of dedifferentiated CRC cells.

Nonsense-mediated RNA decay and its bipolar function in cancer.

Nonsense-mediated decay (NMD) was first described as a quality-control mechanism that targets and rapidly degrades aberrant mRNAs carrying premature termination codons (PTCs). However, it was found that NMD also degrades a significant number of normal transcripts, thus arising as a mechanism of gene expression regulation. Based on these important functions, NMD regulates several biological processes and is involved in the pathophysiology of a plethora of human genetic diseases, including cancer. The present review aims to discuss the paradoxical, pro- and anti-tumorigenic roles of NMD, and how cancer cells have exploited both functions to potentiate the disease. Considering recent genetic and bioinformatic studies, we also provide a comprehensive overview of the present knowledge of the advantages and disadvantages of different NMD modulation-based approaches in cancer therapy, reflecting on the challenges imposed by the complexity of this disease. Furthermore, we discuss significant advances in the recent years providing new perspectives on the implications of aberrant NMD-escaping frameshifted transcripts in personalized immunotherapy design and predictive biomarker optimization. A better understanding of how NMD differentially impacts tumor cells according to their own genetic identity will certainly allow for the application of novel and more effective personalized treatments in the near future.

Perspective in Alternative Splicing Coupled to Nonsense-Mediated mRNA Decay.

Alternative splicing (AS) of precursor mRNA (pre-mRNA) is a cellular post-transcriptional process that generates protein isoform diversity. Nonsense-mediated RNA decay (NMD) is an mRNA surveillance pathway that recognizes and selectively degrades transcripts containing premature translation-termination codons (PTCs), thereby preventing the production of truncated proteins. Nevertheless, NMD also fine-tunes the gene expression of physiological mRNAs encoding full-length proteins. Interestingly, around one third of all AS events results in PTC-containing transcripts that undergo NMD. Numerous studies have reported a coordinated action between AS and NMD, in order to regulate the expression of several genes, especially those coding for RNA-binding proteins (RBPs). This coupling of AS to NMD (AS-NMD) is considered a gene expression tool that controls the ratio of productive to unproductive mRNA isoforms, ultimately degrading PTC-containing non-functional mRNAs. In this review, we focus on the mechanisms underlying AS-NMD, and how this regulatory process is able to control the homeostatic expression of numerous RBPs, including splicing factors, through auto- and cross-regulatory feedback loops. Furthermore, we discuss the importance of AS-NMD in the regulation of biological processes, such as cell differentiation. Finally, we analyze interesting recent data on the relevance of AS-NMD to human health, covering its potential roles in cancer and other disorders.

Experimental supporting data on DIS3L2 over nonsense-mediated mRNA decay targets in human cells.

In this article, we present supportive data related to the research article "A role for DIS3L2 over natural nonsense-mediated mRNA decay targets in human cells" [1], where interpretation of the data presented here is available. Indeed, here we analyze the impact of the DIS3L2 exoribonuclease over nonsense-mediated mRNA decay (NMD)-targets. Specifically, we present data on: a) the expression of various reporter human ß-globin mRNAs, monitored by Northern blot and RT-qPCR, before and after altering DIS3L2 levels in HeLa cells, and b) the gene expression levels of deregulated transcripts generated by re-analyzing publicly available data from UPF1-depleted HeLa cells that were further cross-referenced with a dataset of transcripts upregulated in DIS3L2-depleted cells. These analyses revealed that DIS3L2 regulates the levels of a subset of NMD-targets. These data can be valuable for researchers interested in the NMD mechanism.

A role for DIS3L2 over natural nonsense-mediated mRNA decay targets in human cells.

The nonsense-mediated decay (NMD) pathway selectively degrades mRNAs carrying a premature translation-termination codon but also regulates the abundance of a large number of physiological mRNAs that encode full-length proteins. In human cells, NMD-targeted mRNAs are degraded by endonucleolytic cleavage and exonucleolytic degradation from both 5-' and 3'-ends. This is done by a process not yet completely understood that recruits decapping and 5'-to-3' exonuclease activities, as well as deadenylating and 3'-to-5' exonuclease exosome activities. In yeast, DIS3/Rrp44 protein is the catalytic subunit of the exosome, but in humans, there are three known paralogues of this enzyme: DIS3, DIS3L1, and DIS3L2. However, little is known about their role in NMD. Here, we show that some NMD-targets are DIS3L2 substrates in human cells. In addition, we observed that DIS3L2 acts over full-length transcripts, through a process that also involves UPF1. Moreover, DIS3L2-mediated decay is dependent on the activity of the terminal uridylyl transferases Zcchc6/11 (TUT7/4). Together, our findings establish a role for DIS3L2 and uridylation in NMD.

Clinically Applicable Inhibitors Impacting Genome Stability.

Advances in technology have facilitated the molecular profiling (genomic and transcriptomic) of tumours, and has led to improved stratification of patients and the individualisation of treatment regimes. To fully realize the potential of truly personalised treatment options, we need targeted therapies that precisely disrupt the compensatory pathways identified by profiling which allow tumours to survive or gain resistance to treatments. Here, we discuss recent advances in novel therapies that impact the genome (chromosomes and chromatin), pathways targeted and the stage of the pathways targeted. The current state of research will be discussed, with a focus on compounds that have advanced into trials (clinical and pre-clinical). We will discuss inhibitors of specific DNA damage responses and other genome stability pathways, including those in development, which are likely to synergistically combine with current therapeutic options. Tumour profiling data, combined with the knowledge of new treatments that affect the regulation of essential tumour signalling pathways, is revealing fundamental insights into cancer progression and resistance mechanisms. This is the forefront of the next evolution of advanced oncology medicine that will ultimately lead to improved survival and may, one day, result in many cancers becoming chronic conditions, rather than fatal diseases.

Función telomérica y sirtuinas 1 y 6 en cáncer colorrectal en pacientes obesos y no obesos. Correlaciones clínicas / Telomere function and sirtuins 1 and 6 in colorectal cancer from obese and non-obese patients. Clinical correlations

La disfunción telomérica constituye un evento frecuente en el cáncer colorrectal (CCR). El objetivo de este trabajo consiste en analizar el estatus telomérico y las sirtuinas 1 y 6, en relación con el pronóstico de pacientes afectados de CCR. Asimismo, se investiga la posible relación existente entre la obesidad y la predisposición a desarrollar CCR. Se han investigado parámetros de función telomérica, como la longitud de los telómeros y la actividad telomerasa, así como la expresión relativa de SIRT1 y SIRT6 en muestras de tejido tumoral colorrectal, tejido no tumoral (control), y tejidos adiposos subcutáneo y omental. La longitud telomérica se determinó por las técnicas TRF (Telomere Restriction Fragment) y por PCR cuantitativa (qRT-PCR). La expresión relativa de SIRT1 y SIRT6 se evaluó por qRT-PCR. Los telómeros tumorales críticamente acortados se relacionan con un pronóstico clínico favorable en CCR y se correlacionan con los niveles de expresión más elevados de SIRT1. La expresión reducida de SIRT1 (RQ ≤ 0,5) se detecta en tumores que confieren una evolución clínica más adversa. Los telómeros de las células no tumorales de pacientes obesos o con sobrepeso son significativamente más largos que los de pacientes con normopeso. En tejido adiposo omental, la longitud telomérica relativa es inferior en pacientes obesos con CCR respecto a pacientes obesos sin CCR. El análisis de la longitud telomérica y de SIRT1 presenta interés en la investigación de la evolución clínica de sujetos afectados de CCR y en el establecimiento de la predisposición de individuos obesos al desarrollo de este tipo tumoral

Telomere dysfunction is a frequent event in colorectal cancer (CRC). The aim of this study consists of analyzing telomere status and sirtuins 1 and 6, in relation to the prognosis of patients affected by CRC. We have also investigated the possible relationship between obesity and the predisposition to develop CRC. Telomere function parameters, such as telomere length and telomerase activity, as well as the relative expression of SIRT1 and SIRT6 in samples of colorectal tumor tissue, non-tumor tissue (control), and subcutaneous and omental adipose tissues have been investigated. The telomere length was determined by TRF (Telomere Restriction Fragment) and quantitative PCR (qRT-PCR). The relative expression of SIRT1 and SIRT6 was assessed by qRT-PCR. The critically shortened tumor telomeres were associated with a favorable clinical prognosis in CRC and correlate with the higher expression levels of SIRT1. Reduced expression of SIRT1 (RQ ≤ 0.5) was detected in tumors that confer a more adverse clinical evolution. The telomeres of the non-tumor cells from obese or overweight patients were significantly longer than those of patients showing normal weight. In omental adipose tissue, telomere length was lower in obese patients with CRC than in obese patients without CRC. Analyses of the telomeric length and SIRT1 seem of interest in the investigation of the clinical evolution of subjects affected by CRC and in the establishment of the predisposition of obese individuals to the development of this tumor type

[Some observations on high specialty medical care in Mexico]. / Algunas observaciones acerca de la atención médica de alta especialidad en México.

OBJECTIVES: To put forth the concept of highly specialized medical care, in agreement with the nature of its practice, and evaluate the feasibility of creating a support service network. METHODS: Qualitative study of the current practice and requirements for 39 selected medical specialties, using the technique of focused groups of experts in each specialty. In accordance with the "Grounded Theory", variables were systematized and categorized and then compared in order to identify relationships between categories and link them to consensus testimonial references. On the basis of the characteristics of each kind of practice, one key expert integrated and validated service portfolios. RESULTS: We developed an integrated a concept for highly specialize medical care with 39 operational catalogs of those diagnoses that belong to each specialty, along with catalogs of the resources required by each specialty. CONCLUSIONS: Highly specialized care is a desirable model for clinical practice, but does not constitute a different level of care. Currently, medical practice is constrained by the lack of well-defined boundaries and scarcity of resources in order to be conceptualized as high specialty. It is therefore more convenient to strengthen the concept of third level of care in order to identify opportunities for the establishment of high specialty areas that will in turn serve as the focal points for medical innovation.

[Development of a position on sexuality in health care providers]. / Desarrollo de una postura ante la sexualidad en personal de salud.

BACKGROUND: two attitudes were considered about sexual practice; one is centered in the reproduction, attaching to as a natural thing and intolerance to different expressions of sexuality. The other view according to prevent damage and sexual practices without guilt, bashful attitudes and intolerance. Our objective was to evaluate the effect of an educational intervention, upon the development of the position on sexuality in health care providers. METHODS: study of comparative intervention. Two experimental groups and one control group with initial and final measurements were used. To compare two groups we used the U tests of Mann-Whitney and Kruskal-Wallis. RESULTS: the initial median of the experimental group 1 (GE1) and the witness (GT) were equal and significantly different from the experimental group 2 (GE2); in this one, only 31% of its members initiated without position, as opposed to the 100% of the GE1, and of 93 % of the GT. CONCLUSIONS: a high proportion of health care providers had no posture on sexuality. A position was not reached with the accumulating information; it develops through the questioning of their experience, the educational perspective being an essential factor to achieving it.

[Comparison of traditional cardiovascular risk factors frequency among women of different education levels]. / Comparación de frecuencia de factores de riesgo cardiovascular tradicionales en mujeres con distinto nivel educativo.

INTRODUCTION: Ischemic heart disease is the first cause of death in the world in both genders between 30 and 40 years of age. It has been proposed that socioeconomic status could affect the prevalence of cardiovascular risk factors (CVRF), as well as cardiovascular disease incidence and mortality. The purpose of this work was to compare the frequency of CVRF in two groups of women with different educational level. RESULTS: A higher frequency of visceral obesity was identified in the women with lower educational level and hypo-HDL-C in the group of women with higher educational level. Correlation between age and modifiable CVRF was different between the studied groups. A larger proportion of women with higher educational level than those with lower educational level drank alcoholic beverages and smoked cigarettes. DISCUSSION: Frequency of identified modifiable CVRF was similar to that found in other Hispanic-American populations. The inverse relationship between CVRF and educational level, a commonly used measure of socioeconomic status, and prevalence of CVRF informed in English and American studies was not observed in this investigation; probably because social and cultural conditions could affect the educational level in a different manner. Health education programs must take into account the cultural processes of each country, city, or community, regardless of the socioeconomic status, based on social and cultural backgrounds of each group.

Comparación de frecuencia de factores de riesgo cardiovascular tradicionales en mujeres con distinto nivel educativo / Comparison of traditional cardiovascular risk factors frequency among women of different education levels

INTRODUCTION: Ischemic heart disease is the first cause of death in the world in both genders between 30 and 40 years of age. It has been proposed that socioeconomic status could affect the prevalence of cardiovascular risk factors (CVRF), as well as cardiovascular disease incidence and mortality. The purpose of this work was to compare the frequency of CVRF in two groups of women with different educational level. RESULTS: A higher frequency of visceral obesity was identified in the women with lower educational level and hypo-HDL-C in the group of women with higher educational level. Correlation between age and modifiable CVRF was different between the studied groups. A larger proportion of women with higher educational level than those with lower educational level drank alcoholic beverages and smoked cigarettes. DISCUSSION: Frequency of identified modifiable CVRF was similar to that found in other Hispanic-American populations. The inverse relationship between CVRF and educational level, a commonly used measure of socioeconomic status, and prevalence of CVRF informed in English and American studies was not observed in this investigation; probably because social and cultural conditions could affect the educational level in a different manner. Health education programs must take into account the cultural processes of each country, city, or community, regardless of the socioeconomic status, based on social and cultural backgrounds of each group.

[Acceptance and rejection of vasectomy in rural males]. / Aceptación y rechazo de vasectomía en hombres del medio rural.

BACKGROUND: One problem in rural population is the gap between coverage of contraception and scant masculine participation, which could be due to lack of information of to other sociocultural factors. METHODS: We investigated, in two stages, the characteristics or the profile of the sexual and reproductive behavior of males in an exploratory study by means of focus groups to determine their relevant motivations and characteristics and subsequently, a structured questionnaire to ascertain the magnitude of the factors explored. The population corresponded to zones of rural hospital medical services zones of medical services in seven ethnic groups of the Mexican Republic and included men who accepted and who rejected vasectomy. RESULTS: The profile of males who accepted vasectomy allowed to determine that there exist a unsatisfied demand for contraceptive protection and the desire of not having additional children; in addition, we found that the decision to accept vasectomy is determined to a greater extent for reasons different from that of information on the contraceptive method. The important proportion of males who were non-users of contraceptive methods who accepted vasectomy supposed information on contraception to be the most consistent reason; nonetheless, this information was not considered sufficient and timely; thus, adverse economic situation, a certain condition related with the couple such as health or love for the female partner are the more weighty reasons for deciding to accept vasectomy, while the fear of poor sexual performance is the most powerful factor for rejection of vasectomy. CONCLUSIONS: Masculine participation in family planning is a factor that conditions contraceptive coverage and its respective benefits. The profile of the male who accepts vasectomy aids in identifying candidates forthe procedure and in reducing unsatisfied demand. Greater diffusion of information of the contraceptive method of vasectomy, greater links between male needs and vasectomy, and maintaining or increasing access to family planning are required.

[Evaluation of the clinical aptitude in physicians of the first level of attention]. / Evaluación de la aptitud clínica en médicos de primer nivel de atención.

OBJECTIVE: To evaluate the development through time of the clinical aptitude in physicians of the first level of attention and the influence of categories of first level physicians. MATERIAL AND METHODS: In a cross-section design the clinical aptitude was studied in three categories of physicians of the first level of attention: general practitioners with functions of family medicine, family physicians, and family physicians working as head of a clinical department in Family Medicine Units with 10 or more consulting rooms. To evaluate the clinical aptitude, an instrument with 12 real clinical cases and 412 questions was used with nine indicators; this instrument was validated in a previous study. RESULTS: 499 physicians of the three categories were included, the scores range was between 52 and 245, with an average of 169 (41%). When comparing the categories of physicians, significant differences were found, in favor of the physicians with a specialty. There were no differences among heads of clinical departments and family physicians. In the global analysis among indicators no differences were found. When correlating the clinical aptitude with the years of experience, without considering the category, a correlation of 0.02 was obtained. CONCLUSIONS: Experience seems to have no influence in the development of clinical aptitude; passive continuing education seems to have little influence in the physicians deepening into frequent health-problem solving in their practice.