Increased chromosomal radiosensitivity in asymptomatic carriers of a heterozygous BRCA1 mutation

Background: Breast cancer risk increases drastically in individuals carrying a germline BRCA1 mutation. The exposure to ionizing radiation for diagnostic or therapeutic purposes of BRCA1 mutation carriers is counterintuitive, since BRCA1 is active in the DNA damage response pathway. The aim of this study was to investigate whether healthy BRCA1 mutations carriers demonstrate an increased radiosensitivity compared with healthy individuals. Methods: We defined a novel radiosensitivity indicator (RIND) based on two endpoints measured by the G2 micronucleus assay, reflecting defects in DNA repair and G2 arrest capacity after exposure to doses of 2 or 4 Gy. We investigated if a correlation between the RIND score and nonsense-mediated decay (NMD) could be established. Results: We found significantly increased radiosensitivity in the cohort of healthy BRCA1 mutation carriers compared with healthy controls. In addition, our analysis showed a significantly different distribution over the RIND scores (p = 0.034, Fisher’s exact test) for healthy BRCA1 mutation carriers compared with non-carriers: 72 % of mutation carriers showed a radiosensitive phenotype (RIND score 1–4), whereas 72 % of the healthy volunteers showed no radiosensitivity (RIND score 0). Furthermore, 28 % of BRCA1 mutation carriers had a RIND score of 3 or 4 (not observed in control subjects). The radiosensitive phenotype was similar for relatives within several families, but not for unrelated individuals carrying the same mutation. The median RIND score was higher in patients with a mutation leading to a premature termination codon (PTC) located in the central part of the gene than in patients with a germline mutation in the 5′ end of the gene. Conclusions: We show that BRCA1 mutations are associated with a radiosensitive phenotype related to a compromised DNA repair and G2 arrest capacity after exposure to either 2 or 4 Gy. Our study confirms that haploinsufficiency is the mechanism involved in radiosensitivity in patients with a PTC allele, but it suggests that further research is needed to evaluate alternative mechanisms for mutations not subjected to NMD

Expansion of the Human Phenotype Ontology (HPO) knowledge base and resources.

The Human Phenotype Ontology (HPO)-a standardized vocabulary of phenotypic abnormalities associated with 7000+ diseases-is used by thousands of researchers, clinicians, informaticians and electronic health record systems around the world. Its detailed descriptions of clinical abnormalities and computable disease definitions have made HPO the de facto standard for deep phenotyping in the field of rare disease. The HPO\u27s interoperability with other ontologies has enabled it to be used to improve diagnostic accuracy by incorporating model organism data. It also plays a key role in the popular Exomiser tool, which identifies potential disease-causing variants from whole-exome or whole-genome sequencing data. Since the HPO was first introduced in 2008, its users have become both more numerous and more diverse. To meet these emerging needs, the project has added new content, language translations, mappings and computational tooling, as well as integrations with external community data. The HPO continues to collaborate with clinical adopters to improve specific areas of the ontology and extend standardized disease descriptions. The newly redesigned HPO website (www.human-phenotype-ontology.org) simplifies browsing terms and exploring clinical features, diseases, and human genes

Transcriptome Profiling of Whole Blood Cells Identifies PLEK2 and C1QB in Human Melanoma

Developing analytical methodologies to identify biomarkers in easily accessible body fluids is highly valuable for the early diagnosis and management of cancer patients. Peripheral whole blood is a "nucleic acid-rich" and "inflammatory cell-rich" information reservoir and represents systemic processes altered by the presence of cancer cells.We conducted transcriptome profiling of whole blood cells from melanoma patients. To overcome challenges associated with blood-based transcriptome analysis, we used a PAXgene™ tube and NuGEN Ovation™ globin reduction system. The combined use of these systems in microarray resulted in the identification of 78 unique genes differentially expressed in the blood of melanoma patients. Of these, 68 genes were further analyzed by quantitative reverse transcriptase PCR using blood samples from 45 newly diagnosed melanoma patients (stage I to IV) and 50 healthy control individuals. Thirty-nine genes were verified to be differentially expressed in blood samples from melanoma patients. A stepwise logit analysis selected eighteen 2-gene signatures that distinguish melanoma from healthy controls. Of these, a 2-gene signature consisting of PLEK2 and C1QB led to the best result that correctly classified 93.3% melanoma patients and 90% healthy controls. Both genes were upregulated in blood samples of melanoma patients from all stages. Further analysis using blood fractionation showed that CD45(-) and CD45(+) populations were responsible for the altered expression levels of PLEK2 and C1QB, respectively.The current study provides the first analysis of whole blood-based transcriptome biomarkers for malignant melanoma. The expression of PLEK2, the strongest gene to classify melanoma patients, in CD45(-) subsets illustrates the importance of analyzing whole blood cells for biomarker studies. The study suggests that transcriptome profiling of blood cells could be used for both early detection of melanoma and monitoring of patients for residual disease

Degradation of high affinity HuD targets releases Kv1.1 mRNA from miR-129 repression by mTORC1

Little is known about how a neuron undergoes site-specific changes in intrinsic excitability during neuronal activity. We provide evidence for a novel mechanism for mTORC1 kinase–dependent translational regulation of the voltage-gated potassium channel Kv1.1 messenger RNA (mRNA). We identified a microRNA, miR-129, that repressed Kv1.1 mRNA translation when mTORC1 was active. When mTORC1 was inactive, we found that the RNA-binding protein, HuD, bound to Kv1.1 mRNA and promoted its translation. Unexpectedly, inhibition of mTORC1 activity did not alter levels of miR-129 and HuD to favor binding to Kv1.1 mRNA. However, reduced mTORC1 signaling caused the degradation of high affinity HuD target mRNAs, freeing HuD to bind Kv1.1 mRNA. Hence, mTORC1 activity regulation of mRNA stability and high affinity HuD-target mRNA degradation mediates the bidirectional expression of dendritic Kv1.1 ion channels

DETERMINATION OF THE MECHANISM OF INITIATION OF POLIOVIRUS PROTEIN SYNTHESIS.

It is well documented that shortly after infection with poliovirus, host protein synthesis is inhibited. This defect is at the level of initiation and is thought to be caused by a virally-induced alteration of the initiation factor CBPII. This factor is needed for binding and recognition of capped host mRNA to the 40S ribosomal subunit. Consequently, it has been postulated that poliovirus RNA itself is able to initiate protein synthesis via a "cap-independent" mechanism. In order to define the concept of a "cap-independent" mechanism more fully, the importance of the 5' terminus and 5' noncoding region were investigated. Consequently, restriction fragments from the poliovirus clones, pVR104 and pVR105, were selected which hybridized in four regions of the poliovirus genome: (a) a site within the coding sequence; (b) the area covering the AUG at the beginning of the NCVPOO reading frame; (c) a region in the middle of the 5' untranslated region of the genome; (d) the 5' terminal region of the genome. Hybrid molecules were used to program a micrococcal nuclease treated, PV1-infected cell-free system. Message function was measured by the synthesis of protein products, analyzed by SDS-PAGE, formation of polyribosomes and initiation complexes. As expected, the hybrid formed within the coding region allowed the synthesis of the predicted truncated protein. The hybrid covering the AUG codon at position N743 prevented translation. Interestingly, the hybrid in the untranslated 5' region and the hybrid formed at the 5' terminal sequence, inhibited translation and prevented formation of an initiation complex and polyribosomes. This suggested that poliovirus mRNA, despite its lack of a 5' cap, interacts with ribosomes in an manner similar to capped eucaryotic mRNAs and in agreement with a proposed scanning mechanism. Virus specific RNA binding proteins were also characterized in a preliminary investigation to determine which viral proteins exhibit RNA binding capability and through this interaction direct the functional role that the RNA plays within the cell. It was determined that four virus specific proteins do exhibit RNA binding properties. Due to the known functions of these viral proteins, it is unlikely that any of these proteins are responsible for the translational advantage of PV1 RNA in infected cells

Hyperthermia-Induced Drug Delivery from Thermosensitive Liposomes Encapsulated in an Injectable Hydrogel for Local Chemotherapy

A novel drug delivery system, enabling an in situ, thermally triggered drug release is described, consisting of an injectable thermoresponsive chitosan hydrogel containing doxorubicin-loaded thermosensitive liposomes. The design, fabrication, characterization, and an assessment of in vitro bioactivity of this formulation is detailed. Combining on-demand drug delivery with in situ gelation results in a promising candidate for local chemotherap

Medication Adherence in Children and Adolescents with HIV Infection: Associations with Behavioral Impairment

The impact of behavioral functioning on medication adherence in children with perinatally acquired HIV infection is not well-explored, but has important implications for intervention. This report addresses the relationship between behavioral functioning and child self-report or caregiver report of medication adherence among children and adolescents enrolled in Pediatric AIDS Clinical Trials Group Protocol 219C (conducted 2000–2007). A total of 1134 participants, aged 3–17 years, received a behavioral evaluation and adherence assessment. Complete adherence was defined as taking 100% of prescribed antiretroviral medications during three days preceding the study visit. Multivariable logistic regression models were used to evaluate associations between adherence and behavioral functioning, adjusting for potential confounders, including demographic, psychosocial, and health factors. Children demonstrated higher than expected rates of behavioral impairment (≈7% expected with T > 65) in the areas of conduct problems (14%, z = 7.0, p < 0.001), learning problems (22%, z = 12.2, p < 0.001), somatic complaints (22%, z = 12.6, p < 0.001), impulsivity-hyperactivity (20%, z = 11.1, p < 0.001), and hyperactivity (19%, z = 10.6, p < 0.001). Children with behavioral impairment in one or more areas had significantly increased odds of nonadherence [adjusted odds ratio (aOR) = 1.49, p = 0.04]. The odds of nonadherence were significantly higher for those with conduct problems and general hyperactivity (aOR = 2.03, p = 0.005 and aOR = 1.68, p = 0.02, respectively). Psychosocial and health factors, such as recent stressful life events and higher HIV RNA levels, were also associated with nonadherence. Knowledge of behavioral, health, and social influences affecting the child and family should guide the development of appropriate, evidence-based interventions for medication adherence

Increased chromosomal radiosensitivity in asymptomatic carriers of a heterozygous BRCA1 mutation

Background: Breast cancer risk increases drastically in individuals carrying a germline BRCA1 mutation. The exposure to ionizing radiation for diagnostic or therapeutic purposes of BRCA1 mutation carriers is counterintuitive, since BRCA1 is active in the DNA damage response pathway. The aim of this study was to investigate whether healthy BRCA1 mutations carriers demonstrate an increased radiosensitivity compared with healthy individuals. Methods: We defined a novel radiosensitivity indicator (RIND) based on two endpoints measured by the G2 micronucleus assay, reflecting defects in DNA repair and G2 arrest capacity after exposure to doses of 2 or 4 Gy. We investigated if a correlation between the RIND score and nonsense-mediated decay (NMD) could be established. Results: We found significantly increased radiosensitivity in the cohort of healthy BRCA1 mutation carriers compared with healthy controls. In addition, our analysis showed a significantly different distribution over the RIND scores (p = 0.034, Fisher's exact test) for healthy BRCA1 mutation carriers compared with non-carriers: 72 % of mutation carriers showed a radiosensitive phenotype (RIND score 1-4), whereas 72 % of the healthy volunteers showed no radiosensitivity (RIND score 0). Furthermore, 28 % of BRCA1 mutation carriers had a RIND score of 3 or 4 (not observed in control subjects). The radiosensitive phenotype was similar for relatives within several families, but not for unrelated individuals carrying the same mutation. The median RIND score was higher in patients with a mutation leading to a premature termination codon (PTC) located in the central part of the gene than in patients with a germline mutation in the 5' end of the gene. Conclusions: We show that BRCA1 mutations are associated with a radiosensitive phenotype related to a compromised DNA repair and G2 arrest capacity after exposure to either 2 or 4 Gy. Our study confirms that haploinsufficiency is the mechanism involved in radiosensitivity in patients with a PTC allele, but it suggests that further research is needed to evaluate alternative mechanisms for mutations not subjected to NMD