Genetic analysis in the Collaborative Cross breeding population

Genetic reference populations in model organisms are critical resources for systems genetic analysis of disease related phenotypes. The breeding history of these inbred panels may influence detectable allelic and phenotypic diversity. The existing panel of common inbred strains reflects historical selection biases, and existing recombinant inbred panels have low allelic diversity. All such populations may be subject to consequences of inbreeding depression. The Collaborative Cross (CC) is a mouse reference population with high allelic diversity that is being constructed using a randomized breeding design that systematically outcrosses eight founder strains, followed by inbreeding to obtain new recombinant inbred strains. Five of the eight founders are common laboratory strains, and three are wild-derived. Since its inception, the partially inbred CC has been characterized for physiological, morphological, and behavioral traits. The construction of this population provided a unique opportunity to observe phenotypic variation as new allelic combinations arose through intercrossing and inbreeding to create new stable genetic combinations. Processes including inbreeding depression and its impact on allelic and phenotypic diversity were assessed. Phenotypic variation in the CC breeding population exceeds that of existing mouse genetic reference populations due to both high founder genetic diversity and novel epistatic combinations. However, some focal evidence of allele purging was detected including a suggestive QTL for litter size in a location of changing allele frequency. Despite these inescapable pressures, high diversity and precision for genetic mapping remain. These results demonstrate the potential of the CC population once completed and highlight implications for development of related populations.     

RANKL expression in normal and malignant breast tissue responds to progesterone and is up-regulated during the luteal phase

The receptor activator of nuclear factor-κB ligand (RANKL) acts as a paracrine factor in progesterone-induced mammary epithelial proliferation and tumorigenesis. This evidence comes mainly from mouse models. Our aim was to examine whether RANKL expression in human normal and malignant breast is under the control of progesterone throughout the menstrual cycle. Breast epithelial samples were obtained by random fine needle aspiration (rFNA) of the contralateral unaffected breasts (CUB) of 18 breast cancer patients, with simultaneous serum hormone measurements. Genes correlated with serum progesterone levels were identified through Illumina microarray analysis. Validation was performed using qRT-PCR in rFNA samples from CUB of an additional 53 women and using immunohistochemistry in tissue microarrays of 61 breast cancer samples. Expression of RANKL, DIO2, and MYBPC1 was correlated with serum progesterone in CUB, and was significantly higher in luteal phase. RANKL and MYBPC1 mRNA expression were highly correlated between CUB and matched tumor samples. RANKL protein expression was also significantly increased in the luteal phase and highly correlated with serum progesterone levels in cancer samples, especially in hormone receptor positive tumors. The regulatory effects of progesterone on the expression of RANKL, DIO2, and MYBPC1 were confirmed in three-dimensional cultures of normal breast organoids. In normal breast and in breast cancer, RANKL mRNA and protein expression fluctuate with serum progesterone with highest levels in the luteal phase, suggesting that RANKL is a modulator of progesterone signaling in normal and malignant breast tissue and a potential biomarker of progesterone action and blockade.     

Gender differences in cigarette smoking, social correlates and cessation among adolescents

Background

Despite well-established gender differences in adult smoking behaviors, relatively little is known about gender discrepancies in smoking behaviors among adolescents, and even less is known about the role of gender in smoking cessation among teen populations.

Method

The present study examined gender differences in a population of 755 adolescents seeking to quit smoking through the American Lung Association's Not-On-Tobacco (N-O-T) program. All participants enrolled in the N-O-T program between 1998 and 2009. All participants completed a series of questionnaires prior to and immediately following the cessation intervention. Analyses examined gender differences in a range of smoking variables, cessation success and direct and indirect effects on changes in smoking behaviors.

Results

Females were more likely to have parents, siblings and romantic partners who smokes, perceive that those around them will support a cessation effort, smoke more prior to intervention if they have friends who smoke, and to have lower cessation motivation and confidence if they have a parent who smokes. Conversely, males were more likely to have lower cessation motivation and confidence and be less likely to quit if they have a friend who smokes.

Conclusions

Gender plays an important role in adolescent smoking behavior and smoking cessation. Further research is needed to understand how these differences may be incorporated into intervention design to increase cessation success rates among this vulnerable population of smokers.     

Exploring the Severity of Dependence Scale (SDS) as a possible measure of nicotine dependence

ABSTRACT

Background: The time to first cigarette (TTFC) of the day is an emerging single-item indicator of nicotine dependence due to its robust associations with indices of physical dependence. However, it is unclear if this measure adequately captures other dimensions of dependence. The Severity of Dependence Scale (SDS) is a brief questionnaire used to assess psychological aspects of dependence that has not yet been extensively applied to smoking research. Methods: We examined associations between the SDS and TTFC among 255 smokers during the baseline session of a cessation trial. We also examined associations of the SDS and TTFC with biobehavioral dependence indices, quitting behaviors, and cognitive-affective variables and compared the relative contributions of both measures in predicting these variables. Results: TTFC was unrelated to SDS total score, but was related to individual SDS items. TTFC, but not SDS, was correlated with indices of physical dependence (e.g., cigarettes per day [CPD], carbon monoxide [CO]). Both TTFC and SDS were associated with quitting behaviors, with opposite directionality of associations. TTFC and SDS were both associated with cognitive-affective variables, but SDS outperformed TTFC in strength and number of these relationships. Including both the SDS and TTFC as regression model predictors often increased the amount of variance explained. Conclusions: Findings suggest that SDS and TTFC assess different constructs of nicotine dependence; among smokers, the SDS appears to tap into nonphysical components of dependence (e.g., loss of control) that relate to quitting motivation and affect. Assessing nicotine dependence using only the SDS may fail to capture physical dependence and, further, may not reflect the same domains of addiction the SDS assesses in other drugs of abuse. Nonetheless, using 3 SDS items in addition to TTFC may offer utility over using TTFC alone.     

Evaluation of pharmacodynamic biomarkers in a Phase 1a trial of dulanermin (rhApo2L/TRAIL) in patients with advanced tumours

Background:

Dulanermin (rhApo2L/TRAIL) induces apoptosis by binding to death receptors DR4 and DR5, leading to caspase activation and subsequent cell death. A Phase1a trial evaluated the safety and tolerability of dulanermin in patients with advanced tumours. One aim was to develop and validate pharmacodynamic biomarkers to monitor dulanermin activity in patient serum.

Methods:

We optimised assays to measure the cell-death markers caspase 3/7, cytokeratin 18 and genomic DNA in serum. Mice bearing Colo205 xenografts were treated with dulanermin and sera were collected and assayed for apoptotic markers. Upon validating these assays, we monitored apoptotic markers in patients who received dulanermin.

Results:

We detected transient increases in apoptotic markers in mouse sera 8–24 h after dulanermin treatment. This increase was dose-dependent and correlated with active caspase 3 detected by IHC in Colo205 tumours. A statistically significant increase in serum caspase 3/7 was detected in cohorts of colorectal and sarcoma patients 24 h after receiving dulanermin dosed above 4 mg kg⁻¹.

Conclusion:

Owing to limited responses in the Phase 1a study, the changes in circulating cell-death markers were not evaluable. Future studies with dulanermin are needed to determine the utility of these assays with respect to providing evidence of activity or predicting overall response.     

Characterization of 2-(2,6-dichloro-benzyl)-thiazolo[5,4-d]pyrimidin-7-yl]-(4-trifluoromethyl-phenyl)-amine (JNJ-39729209) as a novel TRPV1 antagonist

As an integrator of multiple nociceptive and/or inflammatory stimuli, TRPV1 is an attractive therapeutic target for the treatment of various painful disorders. Several TRPV1 antagonists have been advanced into clinical trials and the initial observations suggest that TRPV1 antagonism may be associated with mild hyperthermia and thermal insensitivity in man. However, no clinical efficacy studies have been described to date, making an assessment of risk:benefit impossible. Furthermore, it is not clear whether these early observations are representative of all TRPV1 antagonists and whether additional clinical studies with novel TRPV1 antagonists are required in order to understand optimal compound characteristics. In the present study we describe 2-(2,6-dichloro-benzyl)-thiazolo[5,4-d]pyrimidin-7-yl]-(4-trifluoromethyl-phenyl)-amine (JNJ-39729309) as a novel, TRPV1 antagonist. JNJ-39729209 displaced tritiated resiniferotoxin binding to TRPV1 and prevented TRPV1 activation by capsaicin, protons and heat. In-vivo, JNJ-39729209 blocked capsaicin-induced hypotension, induced a mild hyperthermia and inhibited capsaicin-induced hypothermia in a dose dependent manner. JNJ-39729209 showed significant efficacy against carrageenan- and CFA-evoked thermal hyperalgesia and exhibited significant anti-tussive activity in a guinea-pig model of capsaicin-induced cough. In pharmacokinetic studies, JNJ-39729209 was found to have low clearance, a moderate volume of distribution, good oral bioavailability and was brain penetrant. On the basis of these findings, JNJ-39729209 represents a structurally novel TRPV1 antagonist with potential for clinical development. The advancement of JNJ-39729209 into human clinical trials could be useful in further understanding the analgesic potential of TRPV1 antagonists.     

Detection of endolymphatic hydrops using traditional MR imaging sequences

Purpose

The purpose of this study was to determine whether Meniere's disease (MD) produces endolymphatic cavity size changes that are detectable using unenhanced high-resolution T2-weighted MRI.