Hotspot mutations in the spliceosome gene SF3B1 are reported in ∼20% of uveal melanomas. SF3B1 is involved in 3′-splice site (3′ss) recognition during RNA splicing; however, the molecular mechanisms of its mutation have remained unclear. Here we show, using RNA-Seq analyses of uveal melanoma, that the SF3B1R625/K666 mutation results in deregulated splicing at a subset of junctions, mostly by the use of alternative 3′ss. Modelling the differential junctions in SF3B1WT and SF3B1R625/K666 cell lines demonstrates that the deregulated splice pattern strictly depends on SF3B1 status and on the 3'ss-sequence context. SF3B1WT knockdown or overexpression do not reproduce the SF3B1R625/K666 splice pattern, qualifying SF3B1R625/K666 as change-of-function mutants. Mutagenesis of predicted branchpoints reveals that the SF3B1R625/K666-promoted splice pattern is a direct result of alternative branchpoint usage. Altogether, this study provides a better understanding of the mechanisms underlying splicing alterations induced by mutant SF3B1 in cancer, and reveals a role for alternative branchpoints in disease.
MotivationReverse phase protein array (RPPA) is a powerful dot-blot technology that allows studying protein expression levels as well as post-translational modifications in a large number of samples simultaneously. Yet, correct interpretation of RPPA data has remained a major challenge for its broad-scale application and its translation into clinical research. Satisfying quantification tools are available to assess a relative protein expression level from a serial dilution curve. However, appropriate tools allowing the normalization of the data for external sources of variation are currently missing.ResultsHere we propose a new method, called NormaCurve, that allows simultaneous quantification and normalization of RPPA data. For this, we modified the quantification method SuperCurve in order to include normalization for (i) background fluorescence, (ii) variation in the total amount of spotted protein and (iii) spatial bias on the arrays. Using a spike-in design with a purified protein, we test the capacity of different models to properly estimate normalized relative expression levels. The best performing model, NormaCurve, takes into account a negative control array without primary antibody, an array stained with a total protein stain and spatial covariates. We show that this normalization is reproducible and we discuss the number of serial dilutions and the number of replicates that are required to obtain robust data. We thus provide a ready-to-use method for reliable and reproducible normalization of RPPA data, which should facilitate the interpretation and the development of this promising technology.AvailabilityThe raw data, the scripts and the NormaCurve package are available at the following web site: http://microarrays.curie.fr.
Background:The SHIVA trial is a multicentric randomised proof-of-concept phase II trial comparing molecularly targeted therapy based on tumour molecular profiling vs conventional therapy in patients with any type of refractory cancer. Results of the feasibility study on the first 100 enrolled patients are presented.Methods:Adult patients with any type of metastatic cancer who failed standard therapy were eligible for the study. The molecular profile was performed on a mandatory biopsy, and included mutations and gene copy number alteration analyses using high-throughput technologies, as well as the determination of oestrogen, progesterone, and androgen receptors by immunohistochemistry (IHC).Results:Biopsy was safely performed in 95 of the first 100 included patients. Median time between the biopsy and the therapeutic decision taken during a weekly molecular biology board was 26 days. Mutations, gene copy number alterations, and IHC analyses were successful in 63 (66%), 65 (68%), and 87 (92%) patients, respectively. A druggable molecular abnormality was present in 38 patients (40%).Conclusions:The establishment of a comprehensive tumour molecular profile was safe, feasible, and compatible with clinical practice in refractory cancer patients.
Objectives Research on men who have sex with men (MSM) in sub-Saharan Africa was neglected for a long time. The objective of this study was to understand factors associated with unprotected anal intercourse (UAI) with male partners among a group of MSM living in the city of Douala, Cameroon. Methods In 2008, a survey on the sexual activity and practices of MSM was set up in Douala in collaboration with a local community-based organisation. Data were collected among a convenience sample of 168 MSM during face-to-face interviews with trained interviewers. Results A total of 142 individuals reported sexual activity during the previous 6 months, among whom 80 (57%) reported UAI with male partners. In a multivariate logistic regression model adjusted for the frequency of sexual intercourse, not having had access to prevention interventions and not knowing any HIV-infected person were both independently associated with a higher risk of UAI. Other factors associated with this higher risk included having had a stable male partnership at some point in one's life and not having been out of Douala for more than 4 weeks during the previous year. Conclusions This community-based research is the first study of MSM in Cameroon and the HIV transmission risks they face. Results show the importance of HIV prevention interventions from peers, and underline the need to maintain efforts to develop specific interventions targeting MSM more efficiently in the African context.
The sexuality of people living with HIV (PLHIV) is a key issue in the fight against HIV, as it influences both the dynamic of the epidemic and the quality of life of PLHIV. The present study examined the factors associated with cessation of sexual relations after HIV diagnosis among men and women in five countries: Mali, Morocco, Democratic Republic of the Congo, Romania and Ecuador. A community-based cross-sectional study was implemented by a mixed consortium [researchers/community-based organizations (CBO)]. Trained CBO members interviewed 1500 PLHIV in contact with CBOs using a 125-item questionnaire. A weighted multivariate logistic regression and a separate gender analysis were performed. Among the 1413 participants, 471 (33%) declared that they stopped having sexual relations after their HIV diagnosis, including 318 women (42%) and 153 men (23%) (p < .001). Concerning women, variables associated with the cessation of sexual relations in the final multivariate model were mainly related with relational factors and the possibility of getting social support (e.g., needing help to disclose HIV serostatus, feeling lonely every day, not finding support in CBOs, not being in a couple). Men's sexual activity was more associated with their representations and their perception of the infection (e.g., thinking they will have their HIV infection for the rest of their life, perceiving the HIV infection as a mystery, perceiving the infection as serious). Furthermore, the following variables were associated with both men and women sexual behaviours: being older, having suffered from serious social consequences after serostatus disclosure and not being able to regularly discuss about HIV with their steady partner. Results suggested clear differences between men and women regarding cessation of sexual relations and highlighted the importance of implementing gender-based tailored interventions that promote safe and satisfying sexuality, as it is known to have a positive impact on the overall well-being of PLHIV.
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