Targeting the Notch Pathway to Prevent Rejection

Immune rejection is mediated by a complex interplay of cellular and humoral mechanisms. Current therapeutic strategies, which rely on global immunosuppression, can result in serious complications and are not completely effective. Notch signaling is a cell-to-cell communication pathway that plays an important role during T cell development and in the regulation of peripheral immune responses. Initial work, performed mainly through gain-of-function approaches, paradoxically identified Notch as an inducer of tolerance; however, recent studies using loss-of-function approaches in mouse models of transplant rejection and graft-versus-host disease have clarified an important role for Notch as a central mediator of T cell alloreactivity. Short-term inhibition of individual Notch ligands in the peritransplant period had long-lasting protective effects. In a vascularized heart allograft model, blockade of Delta-like Notch ligands dampened both cellular and humoral rejection. In this minireview, we summarize current knowledge about the role of Notch signaling during allograft rejection and provide an overarching mechanism through which Notch acts to promote T cell pathogenicity and allograft damage. We propose that targeting elements of the Notch pathway could provide a new therapeutic approach to prevent allograft rejection.

Molecular changes in appearance of a cancer cell among normal HEK293T cells

In very early stages of cancer development, one or a few cells expressing cancer-associated genes appear among a much larger number of surrounding normal cells. To analyze the molecular changes induced by this co-existence, we artificially prepared transformed cells with complete loss of tumor suppressor gene, SCRIB, among normal human embryonic kidney (HEK293T) cells. A cell strain with SCRIB-knockout was successfully constructed by using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 nuclease system and co-cultured with normal cells. By measuring the time-course changes in cell numbers when SCIRB-knockout cells (cancer model) or cells with normal level of SCRIB expression were respectively co-cultured with wild-type normal HEK293T cells, it was shown that the SCRIB-knockout strain was beneficial for proliferation when mixed together with normal cells. Moreover, as a result of proteome analysis on wild-type cells separated from co-culture with SCRIB-knockout cells, a total of 843 proteins were identified, among which 139 proteins were specific. Among the specifically identified proteins, 22 proteins were annotated to be involved in cytoskeletons including microtubule motor activity-associated proteins. It was implied that molecular changes in cytoskeletons occurred in normal cells when co-cultured with SCRIB knockout cells, but the SCRIB knockout might affect proliferation of the transformed cells with SCRIB knockout by defensive or offensive mechanism of surrounding normal cells.

When efficacy beliefs affect team attributions: relationships between self- and collective efficacy beliefs and team attributions over time

BACKGROUND

This study investigated the extent to which efficacy beliefs and perceptions of team performance influenced team causal attributions overtime.

METHODS

A total of 258 undergraduate students were assigned to a three or four person team and played three games against three different opponents in a semi-round robin team bowling tournament.

RESULTS

Multilevel modelling analyses revealed that individuals' perceptions in team performance were positively associated with internal, stable, and team controllable attributions. Collective efficacy beliefs positively predicted team attributions overtime; whereas, self-efficacy beliefs were a negative predictor of team attributions across the tournament.

CONCLUSIONS

The results indicated that individuals' perceptions of their team's success/failure were the stronger determinant of team attributions than their team's winning/losing and, as well as, the efficacy beliefs - team attributions relationships were moderated by time.

Term elective induction of labour and perinatal outcomes in obese women: retrospective cohort study

OBJECTIVE

To compare perinatal outcomes between elective induction of labour (eIOL) and expectant management in obese women.

DESIGN

Retrospective cohort study.

SETTING

Deliveries in California in 2007.

POPULATION

Term, singleton, vertex, nonanomalous deliveries among obese women (n = 74 725).

METHODS

Women who underwent eIOL at 37 weeks were compared with women who were expectantly managed at that gestational age. Similar comparisons were made at 38, 39, and 40 weeks. Results were stratified by parity. Chi-square tests and multivariable logistic regression were used for statistical comparison.

MAIN OUTCOME MEASURES

Method of delivery, severe perineal lacerations, postpartum haemorrhage, chorioamnionitis, macrosomia, shoulder dystocia, brachial plexus injury, respiratory distress syndrome.

RESULTS

The odds of caesarean delivery were lower among nulliparous women with eIOL at 37 weeks [odds ratio (OR) 0.55, 95% confidence interval (CI) 0.34-0.90] and 39 weeks (OR 0.77, 95% CI 0.63-0.95) compared to expectant management. Among multiparous women with a prior vaginal delivery, eIOL at 37 (OR 0.39, 95% CI 0.24-0.64), 38 (OR 0.65, 95% CI 0.51-0.82), and 39 weeks (OR 0.67, 95% CI 0.56-0.81) was associated with lower odds of caesarean. Additionally, eIOL at 38, 39, and 40 weeks was associated with lower odds of macrosomia. There were no differences in the odds of operative vaginal delivery, lacerations, brachial plexus injury or respiratory distress syndrome.

CONCLUSIONS

In obese women, term eIOL may decrease the risk of caesarean delivery, particularly in multiparas, without increasing the risks of other adverse outcomes when compared with expectant management.

The behaviour of residual tumour after the intentional incomplete excision of a vestibular schwannoma: is it such a bad thing to leave some behind?

OBJECTIVES

To evaluate the biological behaviour of tumour remnants intentionally left in the surgical bed following the incomplete excision of vestibular schwannomas (VS) and to review the relation between extent of resection and preservation of facial nerve function.

METHODS

A retrospective chart review of 450 patients who underwent surgery for resection of VS over 23 years (1992-2014). Of these, 50 (11%) patients had residual tumour intentionally left on/around the facial nerve (near-total or subtotal excision) to preserve facial nerve function intra-operatively. The growth of residual tumour was evaluated using serial magnetic resonance imaging scanning; pre- and postoperative facial nerve function was assessed using the House-Brackmann grading scale.

SETTING

Tertiary referral neurotology unit.

RESULTS

Of the 42 non-NF2 cases where the tumour was intentionally incompletely excised, 28 (67%) patients underwent subtotal resection (mean follow-up 68.5 ± 39.0 months) and 14 (33%) underwent near-total resection (mean follow-up 72.9 ± 48.3 months). Three patients (all in subtotal resection group) showed regrowth. This was not statistically different from the near-total resection group (χ² = 0.92, P = 0.31). The mean overall growth for these cases was 0.68 mm ± 0.32 mm/year. 5 (one near total, four subtotal) of the eight NF2 patients (62.5%) were excluded from our analysis. In the non-NF2 group, poor facial nerve outcomes (House-Brackmann scores of III-IV) were seen in 2/14 and V-VI in 3/14 of the near total compared with 7/25 and 4/25 respectively in the subtotal group.

CONCLUSIONS

Given that the primary surgery for the VS was only for tumours that were relatively large or grew during conservative treatment, the low rate of tumour remnant growth (7%) is reassuring. It may be appropriate to have a lower threshold for leaving tumour on the facial nerve in non-NF2 patients where complete resection may jeopardise facial nerve function.

Abstract P2-09-04: Implementation of next generation cancer gene panel testing in a large HMO

Background: Next generation cancer gene panel testing is fairly new in clinical practice. Little is known about the diagnostic yield of multigene cancer panel testing in community based hospitals.

Objective: To describe characteristics of a diverse cohort who underwent high/moderate risk multigene panel testing for either a personal or a family history of cancer in a large health plan, and report the proportion of pathogenic/likely pathogenic variants (PV/LPV) and variants of unknown clinical significance (VUS) by race/ethnicity.

Methods: Subjects included all 586 female patients who were referred for genetic counseling and underwent multigene panel testing between July 2014 and January 2015. Based on a literature review, the custom-designed high/moderate risk gene panel included 20 cancer susceptibility genes (described below). All tests were performed by the same commercial laboratory (GeneDx).

Results: Of the 586 women, 78 (13.3%) tested positive PV/LPV316 (53.9%) tested negative; and 192 (32.8%) carried one or more VUS. Age at testing ranged from 22-81 years (median 50 years). More women with PV/LPV results tended to be obese than those who tested negative (39.7% vs. 31.2%), and had greater comorbidity (Charlson Index of >3, 35.9% vs. 33.2%).

Of 586 women, 305 (52.0%) had a cancer diagnosis, mainly first primary breast cancer (n=290, 95.1%), while some also had a second primary breast cancer (n=67, 11.4%). Of the 305 women with cancer, 131 (42.9%) were diagnosed prior to the multigene testing implementation (1987-2013), while 174 (57.1%) were diagnosed after implementation.

The cohort was diverse in terms of race/ethnicity: Western/Northern European (31.2%), Latina/Caribbean (30.0%), Asian (14.8%), African-American (7.2%), Ashkenazi Jewish (6.3%), Native American (5.9%), and other (14.9%) (percent exceeds 100% due to mixed race/ethnicity). Of the 192 women who carried a VUS, 60.4% were Western/Northern European, and 46.4% were Latina/Caribbean. Pathogenic or likely pathogenic mutations were higher in Latina /Caribbean women (37.2%), followed by Western/Northern European (26.7%), and African (10.3%). We identified a total of 84 pathogenic mutations among the 78 women with PV/LPV in the following genes: BRCA1 (n=22), BRCA2 (n=17), MUTYH (n=16; all heterozygous), CHEK2 (n=9), ATM (n=4), PALB2 (n=4), PMS2 (n=3), MLH1 (n=2), VHL (n=2), and one mutation in each of the following genes: APC, CDH1, PTEN, TP53, and STK11. VUS were detected in 192 patients (32.7%) of the 586 tested. VUS in ATM (n=57), APC (n=32) and CHEK2 (n=25) comprised 59.4% of all VUS detected.

Discussion: The large percent of VUS was surprising, given that our panel included only high/moderate risk cancer genes. The over-representation of BRCA1/2 among all mutations (45.1%) likely reflected a greater proportion of patients referred for genetic counseling with a personal and/or family breast cancer history. Given that 35% of our positive results were dominant-acting pathogenic or suspected pathogenic mutations, our results suggest that multigene cancer panel testing is an appropriate method for detecting germline mutations in a high-risk cohort in a managed care setting.

Citation Format: Haque R, Alvarado M, Ahmed SA, Chung J, Tiller GE. Implementation of next generation cancer gene panel testing in a large HMO. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-09-04.

27 AN IMPROVED LARGE ANIMAL MODEL FOR THE STUDY OF ADULT STEM CELLS

Murine models for the study of adult stem cell populations have broadened the understanding of previously uncharacterized stem cell niches. The development of murine reporter lines for the leucine-rich repeat-containing G-protein-coupled receptor-5 (Lgr5) has highlighted the importance of this gene as a stem cell marker in the stomach, intestine, hair follicle, liver, and kidney in mice. These models however have significant limitations in terms of translational applications because of anatomical and physiological differences between humans and mice. In order to overcome these limitations, we have sought to develop a porcine LGR5 reporter line. We report the generation of a porcine stem cell reporter line using the combination of transcription activator-like effector nucleases and somatic cell NT. Transcription activator-like effector nuclease-mediated homologous recombination was used to drive the integration of an internal ribosome entry site green fluorescent protein fusion into the 3′ untranslated region of the LGR5 locus in porcine fetal fibroblast cells. Multiple cell lines were developed and screened for the proper integration event. Upon confirmation of proper integration by genomic DNA sequencing, these lines were used as donors for somatic cell NT. Transfer of the somatic cell NT reconstructed embryos to a surrogate gilt resulted in 3 live births, and the establishment of a founder line of LGR5-green fluorescent protein reporter pigs. We have begun to characterise these lines, having observed fluorescent labelling of putative stem cell populations in the intestinal crypts and hair follicles from these animals. Many of these observations parallel the expression patterns observed in similar murine models. We have confirmed the fluorescent reporter signal by immunohistochemistry using an anti-green fluorescent protein antibody, and are working towards colocalization studies using anti-LGR5 antibodies and RNA in situ hybridization, as well as the characterisation of additional stem cell populations in the pig. The development of this line of transgenic pigs represents significant progress toward the study of adult stem cells, their progenitors, and the stem cell niche, using a large animal model with an anatomy, physiology, and ability to recapitulate human disease that overcomes the current limitations of rodent models. Funding was provided by NIH R21OD019738.

The Effect of Improved Water Supply on Diarrhea Prevalence of Children under Five in the Volta Region of Ghana: A Cluster-Randomized Controlled Trial

Although a number of studies have been conducted to explore the effect of water quality improvement, the majority of them have focused mainly on point-of-use water treatment, and the studies investigating the effect of improved water supply have been based on observational or inadequately randomized trials. We report the results of a matched cluster randomized trial investigating the effect of improved water supply on diarrheal prevalence of children under five living in rural areas of the Volta Region in Ghana. We compared the diarrheal prevalence of 305 children in 10 communities of intervention with 302 children in 10 matched communities with no intervention (October 2012 to February 2014). A modified Poisson regression was used to estimate the prevalence ratio. An intention-to-treat analysis was undertaken. The crude prevalence ratio of diarrhea in the intervention compared with the control communities was 0.85 (95% CI 0.74–0.97) for Krachi West, 0.96 (0.87–1.05) for Krachi East, and 0.91 (0.83–0.98) for both districts. Sanitation was adjusted for in the model to remove the bias due to residual imbalance since it was not balanced even after randomization. The adjusted prevalence ratio was 0.82 (95% CI 0.71–0.96) for Krachi West, 0.95 (0.86–1.04) for Krachi East, and 0.89 (0.82–0.97) for both districts. This study provides a basis for a better approach to water quality interventions.

Common Genetic Variant Association with Altered HLA Expression, Synergy with Pyrethroid Exposure, and Risk for Parkinson's Disease: An Observational and Case-Control Study

Background:

The common noncoding single-nucleotide polymorphism (SNP) rs3129882 in HLA-DRA is associated with risk for idiopathic Parkinson’s disease (PD). The location of the SNP in the major histocompatibility complex class II (MHC-II) locus implicates regulation of antigen presentation as a potential mechanism by which immune responses link genetic susceptibility to environmental factors in conferring lifetime risk for PD.

Aims:

The aim of this study was to determine the effect of this SNP on the MHC-II locus and its synergy with pesticide exposure.

Methods:

For immunophenotyping, blood cells from 81 subjects were analyzed by quantitative reverse transcription-PCR and flow cytometry. A case–control study was performed on a separate cohort of 962 subjects to determine association of pesticide exposure and the SNP with risk of PD.

Results:

Homozygosity for G at this SNP was associated with heightened baseline expression and inducibility of MHC class II molecules in B cells and monocytes from peripheral blood of healthy controls and PD patients. In addition, exposure to a commonly used class of insecticide, pyrethroids, synergized with the risk conferred by this SNP (odds ratio=2.48, P=0.007), thereby identifying a novel gene–environment interaction that promotes risk for PD via alterations in immune responses.

Conclusions:

In sum, these novel findings suggest that the MHC-II locus may increase susceptibility to PD through presentation of pathogenic, immunodominant antigens and/or a shift toward a more pro-inflammatory CD4+ T-cell response in response to specific environmental exposures, such as pyrethroid exposure through genetic or epigenetic mechanisms that modulate MHC-II gene expression.

Contrast-enhanced ultrasound (CEUS) versus computed tomography angiography (CTA) in detection of endoleaks in post-EVAR patients. Are delayed type II endoleaks being missed? A systematic review and meta-analysis

PURPOSE

The purpose of this systematic review is to assess the accuracy of contrast-enhanced ultrasound (CEUS) to computed tomography angiography (CTA) for the detection of endoleaks within EVAR surveillance program.

MATERIAL AND METHODS

A systematic review in Pubmed, Embase and Cochrane database was performed. Articles assessing diagnostic accuracy and comparative modality (CTA vs. CEUS) for endoleaks in adult patients within surveillance programs were retrieved. Methodological assessment was performed, using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tools. The sensitivity and specificity of data were extracted and statistical analysis was performed using MetaDiSc version 1.4.

RESULTS

Eight articles were found eligible (n = 454 patients). The pooled sensitivity of CEUS at detecting endoleak is 0.914 (CI 0.866-0.949) and pooled specificity is 0.782 (CI 0.741-0.820).

CONCLUSION

The CEUS with its dynamic nature and longer scanning window demonstrated to be a highly sensitive modality for endoleak detection in comparison to CTA in delayed endoleaks type II.

Processable conducting graphene/chitosan hydrogels for tissue engineering

Electrically conductive, mechanically improved graphene/chitosan/lactic acid composites were synthesised and could be easily processed into multi-layer scaffolds using additive fabrication techniques.