Operational relevance of the Sydney Declaration: The example of the Australian Federal Police (AFP) Forensics Command

In 2022, a group of eminent forensic scientists published The Sydney Declaration - Revisiting the essence of forensic science through its fundamental principles in Forensic Science International. The Sydney Declaration was delivered to revisit "the essence of forensic science, its purpose, and fundamental principles". At its heart, revisiting these foundational principles is hoped to "benefit forensic science as a whole to be more relevant, effective and reliable". But can these principles be translated operationally by a forensic services provider to achieve the benefits prescribed? How do we make the leap from a theoretical concept and begin to put it into practice to bring about the real and meaningful change that the declaration hopes to achieve? In this paper we will attempt to discuss how the Australian Federal Police (AFP) Forensics Command has reflected on the Sydney Declaration by relating reforms developed and implemented to our operating model with some selected principles. We hope to show that while the Sydney Declaration could be perceived as academic and disconnected from operations, it has the potential to impact and positively influence reforms and changes for forensic science providers. The AFP Forensics Command experience shows the operational relevance of The Sydney Declaration.

Measuring the impact of scientific publications and publication extenders: examples of novel approaches

Different stakeholders, such as authors, research institutions, and healthcare professionals (HCPs) may determine the impact of peer-reviewed publications in different ways. Commonly-used measures of research impact, such as the Journal Impact Factor or the H-index, are not designed to evaluate the impact of individual articles. They are heavily dependent on citations, and therefore only measure impact of the overall journal or researcher respectively, taking months or years to accrue. The past decade has seen the development of article-level metrics (ALMs), that measure the online attention received by an individual publication in contexts including social media platforms, news media, citation activity, and policy and patent citations. These new tools can complement traditional bibliometric data and provide a more holistic evaluation of the impact of a publication. This commentary discusses the need for ALMs, and summarizes several examples - PlumX Metrics, Altmetric, the Better Article Metrics score, the EMPIRE Index, and scite. We also discuss how metrics may be used to evaluate the value of "publication extenders" - educational microcontent such as animations, videos and plain-language summaries that are often hosted on HCP education platforms. Publication extenders adapt a publication's key data to audience needs and thereby extend a publication's reach. These new approaches have the potential to address the limitations of traditional metrics, but the diversity of new metrics requires that users have a keen understanding of which forms of impact are relevant to a specific publication and select and monitor ALMs accordingly.

Echocardiographic image collection and evaluation in infants with CHD: lessons learned from the imaging core lab for the Residual Lesion Score study

Many factors affect patient outcome after congenital heart surgery, including the complexity of the heart disease, pre-operative status, patient specific factors (prematurity, nutritional status and/or presence of comorbid conditions or genetic syndromes), and post-operative residual lesions. The Residual Lesion Score is a novel tool for assessing whether specific residual cardiac lesions after surgery have a measurable impact on outcome. The goal is to understand which residual lesions can be tolerated and which should be addressed prior to leaving the operating room. The Residual Lesion Score study is a large multicentre prospective study designed to evaluate the association of Residual Lesion Score to outcomes in infants undergoing surgery for CHD. This Pediatric Heart Network and National Heart, Lung, and Blood Institute-funded study prospectively enrolled 1,149 infants undergoing 5 different congenital cardiac surgical repairs at 17 surgical centres. Given the contribution of echocardiographic measurements in assigning the Residual Lesion Score, the Residual Lesion Score study made use of a centralised core lab in addition to site review of all data. The data collection plan was designed with the added goal of collecting image quality information in a way that would permit us to improve our understanding of the reproducibility, variability, and feasibility of the echocardiographic measurements being made. There were significant challenges along the way, including the coordination, de-identification, storage, and interpretation of very large quantities of imaging data. This necessitated the development of new infrastructure and technology, as well as use of novel statistical methods. The study was successfully completed, but the size and complexity of the population being studied and the data being extracted required more technologic and human resources than expected which impacted the length and cost of conducting the study. This paper outlines the process of designing and executing this complex protocol, some of the barriers to implementation and lessons to be considered in the design of future studies.

INX-315, a Selective CDK2 Inhibitor, Induces Cell Cycle Arrest and Senescence in Solid Tumors

Cyclin-dependent kinase 2 (CDK2) is thought to play an important role in driving proliferation of certain cancers, including those harboring CCNE1 amplification and breast cancers that have acquired resistance to CDK4/6 inhibitors (CDK4/6i). The precise impact of pharmacologic inhibition of CDK2 is not known due to the lack of selective CDK2 inhibitors. Here we describe INX-315, a novel and potent CDK2 inhibitor with high selectivity over other CDK family members. Using cell-based assays, patient-derived xenografts (PDX), and transgenic mouse models, we show that INX-315 (i) promotes retinoblastoma protein hypophosphorylation and therapy-induced senescence (TIS) in CCNE1-amplified tumors, leading to durable control of tumor growth; (ii) overcomes breast cancer resistance to CDK4/6i, restoring cell cycle control while reinstating the chromatin architecture of CDK4/6i-induced TIS; and (iii) delays the onset of CDK4/6i resistance in breast cancer by driving deeper suppression of E2F targets. Our results support the clinical development of selective CDK2 inhibitors.

SIGNIFICANCE

INX-315 is a novel, selective inhibitor of CDK2. Our preclinical studies demonstrate activity for INX-315 in both CCNE1-amplified cancers and CDK4/6i-resistant breast cancer. In each case, CDK2 inhibition induces cell cycle arrest and a phenotype resembling cellular senescence. Our data support the development of selective CDK2 inhibitors in clinical trials. See related commentary by Watts and Spencer, p. 386. This article is featured in Selected Articles from This Issue, p. 384.

Outcomes for central venous catheter repair in patients receiving long-term home parenteral support: A descriptive cohort study

BACKGROUND

Central venous catheter (CVC) complications are frequently reported in patients receiving home parenteral support (HPS). Compromised CVC integrity or breakage is one such issue. Repairing such breakages can potentially avoid costly and risky catheter replacements.

METHODS

We completed a retrospective descriptive cohort study using a prospectively maintained data set, in a national UK intestinal failure reference center. Repair success, CVC longevity, and catheter-related bloodstream infection (CRBSI) rates after repair were the primary outcome measures.

RESULTS

A total of 763 patients received HPS. There were 137 CVC repairs: 115 (84%) tunneled CVCs and 22 peripherally inserted central catheters (PICCs) attempted in 72 patients. Of the 137 attempts at CVC repair, 120 (88%) were deemed to be successful, allowing a median duration of subsequent CVC use of 336 days following repair (range 3-1696 days), which equates to 99,602 catheter days of HPS infusion. Three patients had a CRBSI within 90 days of repair, and patients required admission to the hospital for refeeding on 14 occasions following repair, such that hospitalization was avoided in 103/120 (86%) occasions following successful CVC repair. There was no increase in the recorded rate of CRBSIs in patients undergoing CVC repair compared with the CRBSI rates of all HPS-dependent patients under our care during the study period (0.03 vs 0.344/1000 catheter days, respectively).

CONCLUSION

This is the largest single-center experience to demonstrate that CVCs, including PICCs, used for the administration of HPS can be safely repaired, prolonging CVC longevity without leading to an increased risk of CRBSI.

Reduction is sufficient for the disassembly of ricin and Shiga toxin 1 but not Escherichia coli heat-labile enterotoxin

Many AB toxins contain an enzymatic A moiety that is anchored to a cell-binding B moiety by a disulfide bridge. After receptor-mediated endocytosis, some AB toxins undergo retrograde transport to the endoplasmic reticulum (ER) where reduction of the disulfide bond occurs. The reduced A subunit then dissociates from the holotoxin and enters the cytosol to alter its cellular target. Intoxication requires A chain separation from the holotoxin, but, for many toxins, it is unclear if reduction alone is sufficient for toxin disassembly. Here, we examined the link between reduction and disassembly for several ER-translocating toxins. We found disassembly of the reduced Escherichia coli heat-labile enterotoxin (Ltx) required an interaction with one specific ER-localized oxidoreductase: protein disulfide isomerase (PDI). In contrast, the reduction and disassembly of ricin toxin (Rtx) and Shiga toxin 1 (Stx1) were coupled events that did not require PDI and could be triggered by reductant alone. PDI-deficient cells accordingly exhibited high resistance to Ltx with continued sensitivity to Rtx and Stx1. The distinct structural organization of each AB toxin thus appears to determine whether holotoxin disassembly occurs spontaneously upon disulfide reduction or requires the additional input of PDI.

Longitudinal Follow-Up of Children With HLHS and Association Between Norwood Shunt Type and Long-Term Outcomes: The SVR III Study

OBJECTIVE

In the SVR trial (Single Ventricle Reconstruction), newborns with hypoplastic left heart syndrome were randomly assigned to receive a modified Blalock-Taussig-Thomas shunt (mBTTS) or a right ventricle-to-pulmonary artery shunt (RVPAS) at Norwood operation. Transplant-free survival was superior in the RVPAS group at 1 year, but no longer differed by treatment group at 6 years; both treatment groups had accumulated important morbidities. In the third follow-up of this cohort (SVRIII [Long-Term Outcomes of Children With Hypoplastic Left Heart Syndrome and the Impact of Norwood Shunt Type]), we measured longitudinal outcomes and their risk factors through 12 years of age.

METHODS

Annual medical history was collected through record review and telephone interviews. Cardiac magnetic resonance imaging (CMR), echocardiogram, and cycle ergometry cardiopulmonary exercise tests were performed at 10 through 14 years of age among participants with Fontan physiology. Differences in transplant-free survival and complication rates (eg, arrhythmias or protein-losing enteropathy) were identified through 12 years of age. The primary study outcome was right ventricular ejection fraction (RVEF) by CMR, and primary analyses were according to shunt type received. Multivariable linear and Cox regression models were created for RVEF by CMR and post-Fontan transplant-free survival.

RESULTS

Among 549 participants enrolled in SVR, 237 of 313 (76%; 60.7% male) transplant-free survivors (mBTTS, 105 of 147; RVPAS, 129 of 161; both, 3 of 5) participated in SVRIII. RVEF by CMR was similar in the shunt groups (RVPAS, 51±9.6 [n=90], and mBTTS, 52±7.4 [n=75]; P=0.43). The RVPAS and mBTTS groups did not differ in transplant-free survival by 12 years of age (163 of 277 [59%] versus 144 of 267 [54%], respectively; P=0.11), percentage predicted peak Vo2 for age and sex (74±18% [n=91] versus 72±18% [n=84]; P=0.71), or percentage predicted work rate for size and sex (65±20% versus 64±19%; P=0.65). The RVPAS versus mBTTS group had a higher cumulative incidence of protein-losing enteropathy (5% versus 2%; P=0.04) and of catheter interventions (14 versus 10 per 100 patient-years; P=0.01), but had similar rates of other complications.

CONCLUSIONS

By 12 years after the Norwood operation, shunt type has minimal association with RVEF, peak Vo2, complication rates, and transplant-free survival. RVEF is preserved among the subgroup of survivors who underwent CMR assessment. Low transplant-free survival, poor exercise performance, and accruing morbidities highlight the need for innovative strategies to improve long-term outcomes in patients with hypoplastic left heart syndrome.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT0245531.

Assessment of Local and Regional Control in Atypical (WHO Grade 2) Meningiomas Receiving Fractioned Stereotactic Radiotherapy

PURPOSE/OBJECTIVE(S)

The optimal delivery of postoperative radiotherapy to WHO grade 2 or atypical meningiomas (AM) is controversial. The historical standard of care has been high dose fractionated radiation to the resection bed and a 2 cm CTV as in RTOG 0539. Single fraction radiosurgery offers a more conformal alternative with demonstrated local control for smaller AM in less sensitive areas. Though less studied, fractionated stereotactic radiosurgery (FSRT) promises safer treatment of larger AM in more sensitive locations while minimizing the treated volume. This single institution retrospective review examines the hypothesis that local and marginal failure patterns in AM treated with five fraction FSRT remain unacceptably high.

MATERIALS/METHODS

Thirty-nine patients received 27.5 - 30 Gy in 5 fractions to their AM from 2009 to 2022 with grading based on the WHO criteria active at the time of treatment. All treatments were frameless VMAT deliveries with no PTV margin. Histological diagnosis of AM, gross disease at time of FSRT, five fraction FSRT, and lack of prior local radiation were required for inclusion. Single fraction treatments were excluded. Local recurrence was defined similar to RECIST criteria as an increase of 20% in the greatest cross-sectional diameter on MRI (or CT if MRI contraindicated) with at least one voxel touching the prescription volume. To examine the role of CTV margin, marginal recurrence was defined as any new lesion outside of the prescription volume but within 2 cm of the resection cavity. High grade toxicity per CTCAE v5 was an irreversible grade 3 or any grade 4 toxicity. Resection for radionecrosis was considered a local failure if any viable tumor was seen on pathology.

RESULTS

Median follow up was 32.5 months (range 3.2-147.5 months). The number of AM treated post STR, post GTR recurrence, and definitively were 26, 16, and 5 respectively. 3-year local tumor control was estimated to be 84%. As expected, larger tumors were more likely to fail locally (p >.001). Two (5%) patients experienced high grade toxicity - both symptomatic radionecrosis requiring resection. Three-year marginal control was estimated to be 92.3%. Of the 5 tumors treated to the entire resection cavity, none experienced a marginal failure. Interestingly, recurrent tumors s/p GTR were more likely to recur marginally than tumors treated after STR (p = .009). Only 1 (4%) tumor treated after STR failed marginally while 4 (33%) tumors treated after GTR recurrence failed.

CONCLUSION

The rate of high-grade toxicity in AM receiving FSRT was low. Local control appeared comparable to historical rates which may suggest the need for dose escalation with longer term follow-up. Recurrent tumors appear more prone to marginal failures, however more work is needed to determine which patients may benefit from additional CTV margin and more prolonged fractionated dose schedules. Improved targeting with newer imaging studies (e.g., DOTATATE PET) should be examined to determine if more accurate targeting will improve outcomes.

A systematic approach towards missing lab data in electronic health records: A case study in non-small cell lung cancer and multiple myeloma

Real-world data derived from electronic health records often exhibit high levels of missingness in variables, such as laboratory results, presenting a challenge for statistical analyses. We developed a systematic workflow for gathering evidence of different missingness mechanisms and performing subsequent statistical analyses. We quantify evidence for missing completely at random (MCAR) or missing at random (MAR), mechanisms using Hotelling's multivariate t-test, and random forest classifiers, respectively. We further illustrate how to apply sensitivity analyses using the not at random fully conditional specification procedure to examine changes in parameter estimates under missing not at random (MNAR) mechanisms. In simulation studies, we validated these diagnostics and compared analytic bias under different mechanisms. To demonstrate the application of this workflow, we applied it to two exemplary case studies with an advanced non-small cell lung cancer and a multiple myeloma cohort derived from a real-world oncology database. Here, we found strong evidence against MCAR, and some evidence of MAR, implying that imputation approaches that attempt to predict missing values by fitting a model to observed data may be suitable for use. Sensitivity analyses did not suggest meaningful departures of our analytic results under potential MNAR mechanisms; these results were also in line with results reported in clinical trials.

Maximizing atmospheric-disturbed fiber coupling efficiency with speckle-based phase retrieval and a single-pixel camera

An approach to adaptive optics utilizing a single-pixel camera (SPC) is proposed to maximize fiber coupling efficiency at the receiver side of an optical satellite-to-ground link perturbed by atmospheric turbulence. Using a single-pixel wavefront sensor enables operation at longer optical wavelengths, such as near and far infrared, which have advantageous propagation characteristics for free space optical communication. In this approach, a focal plane intensity image of the atmospheric-disturbed wavefront is taken via an SPC using a compressed sensing technique. An iterative speckle-based phase retrieval algorithm is then applied to infer the phase distortion corrected by a deformable mirror in a feedback loop. This computational approach to inferring the phase of the wavefront overcomes the limitations of traditional Shack-Hartman-based approaches, which are difficult to implement at high speed and at the long infrared wavelengths proposed for future optical satellite communication downlinks. It has been shown that fiber coupling efficiency is increased from less than 5% to 40%-50% in medium-to-strong turbulence scenarios with the phase retrieval algorithm proposed in this work.

Hedgehog target genes regulate lipid metabolism to drive basal cell carcinoma and medulloblastoma

Hedgehog (Hh) signaling is essential for development, homeostasis, and regeneration1. Misactivation of the Hh pathway underlies medulloblastoma, the most common malignant brain tumor in children, and basal cell carcinoma (BCC), the most common cancer in the United States2. Primary cilia regulate Hh signal transduction3, but target genes that drive cell fate decisions in response to ciliary ligands or oncogenic Hh signaling are incompletely understood. Here we define the Hh gene expression program using RNA sequencing of cultured cells treated with ciliary ligands, BCCs from humans, and Hh-associated medulloblastomas from humans and mice (Fig. 1a). To validate our results, we integrate lipidomic mass spectrometry and bacterial metabolite labeling of free sterols with genetic and pharmacologic approaches in cells and mice. Our results reveal novel Hh target genes such as the oxysterol synthase Hsd11β1 and the adipokine Retnla that regulate lipid metabolism to drive cell fate decisions in response to Hh pathway activation. These data provide insights into cellular mechanisms underlying ciliary and oncogenic Hh signaling and elucidate targets to treat Hh-associated cancers.

Magnetization Transfer Contrast - Is it Sensitive Enough to Differentiate Demyelination from Axonal Loss?

Background and Objective

Magnetization transfer contrast imaging (MTC) exploits the principle of exchange of energy between the bound and free protons and was shown to be pathologically informative. There is, however, controversy as to whether it correlates with axonal loss (AL), demyelination (DM), or both. This study addresses the pathophysiological process that underlies the white matter injury using the metric derivative of MTC, magnetization transfer ratio (MTR), and defines the role of MTR in identifying the different stages of inflammation, that is, edema, DM, and AL, using optic nerve as the model.

Materials and Methods

One hundred and forty-two patients with a single, unilateral episode of optic neuritis (ON) were included in the study. Patients were divided into three groups - those with AL, those with DM, and those who were clinically optic neurites but without any electrophysiological changes suggestive of either AL or DM. MTR and electrophysiological studies were performed in the post-acute stage of ON and the results were compared to those obtained from the unaffected optic nerve.

Results

MTR was significantly reduced in the optic nerves of both DM and AL groups when compared to that in normal optic nerves (P < 0.001). The difference in MTR between the AL and DM groups did not reach statistical significance. Patient group with acute ON did not show any change in the MTR values compared to the normal controls.

Conclusions

MTR is a sensitive technique to identify neuronal injury, whether it is DM or AL. It, however, cannot differentiate these two pathological processes. MTR is not sensitive to identify acute ON.

Land use modification causes slow, but predictable, change in soil microbial community composition and functional potential

BACKGROUND

Bacterial communities are critical to ecosystem functioning and sensitive to their surrounding physiochemical environment. However, the impact of land use change on microbial communities remains understudied. We used 16S rRNA gene amplicon sequencing and shotgun metagenomics to assess soil microbial communities' taxonomic and functional responses to land use change. We compared data from long-term grassland, exotic forest and horticulture reference sites to data from sites that transitioned from (i) Grassland to exotic forest or horticulture and from (ii) Exotic forest to grassland.

RESULTS

Community taxonomic and functional profiles of the transitional sites significantly differed from those within reference sites representing both their historic and current land uses (P < 0.001). The bacterial communities in sites that transitioned more recently were compositionally more similar to those representing their historic land uses. In contrast, the composition of communities from sites exposed to older conversion events had shifted towards the compositions at reference sites representing their current land use.

CONCLUSIONS

Our study indicates that microbial communities respond in a somewhat predictable way after a land use conversion event by shifting from communities reflecting their former land use towards those reflecting their current land use. Our findings help us to better understand the legacy effects of land use change on soil microbial communities and implications for their role in soil health and ecosystem functioning. Understanding the responsiveness of microbial communities to environmental disturbances will aid us in incorporating biotic variables into soil health monitoring techniques in the future.

Abstract 6545: Investigating secondary findings in a pediatric cancer cohort: preliminary findings

Purpose: An expected outcome following germline genome sequencing in oncology is the discovery of ‘secondary findings’ (SFs). SFs comprise pathogenic(P)/likely P (LP) germline variants in cancer genes not typically associated with the presenting cancer, in addition to germline variants of uncertain significance (VUS) to the patient’s cancer. Due to the rarity of childhood cancers and a dearth of studies analyzing SFs, many pediatric SFs are categorized as VUS without clinical interpretation. Interpreting SFs poses significant challenges: VUSs and other SFs are frequently not included in clinical molecular reports, and even when reported (often through research), their clinical utility and long-term impact on patient health are unclear. However, we know VUSs can have clinical importance because some VUSs, when investigated thoroughly, have been reclassified as pathogenic predictors of significant health conditions in children. We hypothesize that an in-depth characterization of the landscape of germline SFs/VUSs across a diverse pediatric cancer cohort will reveal new roles of these genes and mutations in pediatric cancers.

Methods: To explore germline SFs in pediatric cancer patients, we analyzed germline whole-genome sequencing (WGS) data for patients with rare, relapsed, refractory, and metastatic childhood cancers enrolled in the SickKids Cancer Sequencing Program (KiCS). We developed a custom analysis pipeline to identify germline single-nucleotide variants and indels deemed SFs, auto-classify their pathogenicity (ex. P, LP, or VUS) using CharGer, filter for PanCanAtlas-indicated cancer predisposition genes, and sort the remaining variants by cancer and non-cancer associations.

Results: The KiCS cohort (n = 511) encompassed over 133 different tumor types; the median age of participants was 14 years (SD = 10.27) and 55% of patients were male. Ongoing work in our lab will catalogue the frequency and distribution of SFs in KiCS and analyze germline variants by subgroup (gene, tumor subtype, stage, demographics, gene function). We will also compare SF prevalence in KiCS to the general population using the gnomAD dataset. Results from preliminary analyses of this cohort will be presented.

Significance: SFs/VUSs are under-utilized in cancer management. This work advances the holistic understanding of germline genomics in pediatric oncology and the roles of SFs in disease. Future studies will evaluate SFs by patient ancestry and validate cancer associations through the evaluation of allelic imbalance/loss of heterozygosity in matched tumor genomes.

Citation Format: Safa Majeed, Stephenie Prokopec, Brianne Laverty, Vallijah Subasri, Michael Taylor, Yvonne Bombard, Trevor Pugh, Adam Shlien, Anita Villani, David Malkin. Investigating secondary findings in a pediatric cancer cohort: preliminary findings. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6545.

Abstract 5994: INX-315, a potent and selective CDK2 inhibitor, demonstrates robust antitumor activity in CCNE1-amplified cancers

Cyclin-dependent kinases (CDK) are a family of serine/threonine kinases that heterodimerize with regulatory subunits called cyclins to drive cell cycle progression. Uncontrolled cellular proliferation is a hallmark of cancer commonly driven by dysregulated kinase activity of specific CDK family members, including cyclin-dependent kinase 2 (CDK2). Aberrant CDK2 activity most frequently occurs through amplification of CCNE1 and/or overexpression of its protein product cyclin E1, which is a canonical binding partner of CDK2. Overexpression of cyclin E1 is observed in many solid tumors including in patients with high grade serous ovarian cancer (HGSOC), gastric cancer, and ER-positive breast cancer patients whose tumors have progressed on a prior CDK4/6 inhibitor regimen. Selective inhibition of CDK2 is thus a compelling therapeutic approach to regain cell cycle control. Here, we report preclinical data supporting the development of INX-315 for patients with cancers in which proliferation is CDK2-dependent. INX-315 is a potent inhibitor of CDK2/cyclin E (0.6 nM biochemical IC50) with high selectivity over other CDK family members in both biochemical and intracellular NanoBRET assays. In CCNE1-amplified human ovarian and gastric cancer cell lines, INX-315 potently inhibited Rb phosphorylation, induced a G1 cell cycle arrest, and inhibited proliferation. INX-315 also showed potent anti-proliferative activity in luminal breast cancer cell lines that had been cultured in CDK4/6 inhibitor (+/- anti-estrogen therapy) for prolonged periods to the point of developing drug resistance. While these cell lines did not readily respond to either CDK4/6 or CDK2 inhibition alone, combination treatment again suppressed Rb phosphorylation, accompanied by G1 arrest and a senescent-like phenotype. Lastly, in CCNE1-amplified xenograft models of ovarian and gastric carcinomas, INX-315 inhibited Rb-phosphorylation and induced tumor regression. These data demonstrate INX-315 to be a potent and selective CDK2 inhibitor that may benefit patients with CDK2/cyclin E driven cancers.

Citation Format: Alec G. Trub, John E. Bisi, Catherine Dietrich, Michael Taylor, Jay C. Strum, Shom Goel, Patrick J. Roberts. INX-315, a potent and selective CDK2 inhibitor, demonstrates robust antitumor activity in CCNE1-amplified cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5994.

Slow, slow, quick, quick, slow: five altmetric sources observed over a decade show evolving trends, by research age, attention source maturity and open access status

The study of temporal trends in altmetrics is under-developed, and this multi-year observation study addresses some of the deficits in our understanding of altmetric behaviour over time. The attention surrounding research outputs, as partially captured by altmetrics, or alternative metrics, constitutes many varied forms of data. Over the years 2008–2013, a set of 7739 papers were sampled on six occasions. Five altmetric data sources were recorded (Twitter, Mendeley, News, Blogs and Policy) and analysed for temporal trends, with particular attention being paid to their Open Access status and discipline. Twitter attention both starts and ends quickly. Mendeley readers accumulate quickly, and continue to grow over the following years. News and blog attention is quick to start, although news attention persists over a longer timeframe. Citations in policy documents are slow to start, and are observed to be growing over a decade after publication. Over time, growth in Twitter activity is confirmed, alongside an apparent decline in blogging attention. Mendeley usage is observed to grow, but shows signs of recent decline. Policy attention is identified as the slowest form of impact studied by altmetrics, and one that strongly favours the Humanities and Social Sciences. The Open Access Altmetrics Advantage is seen to emerge and evolve over time, with each attention source showing different trends. The existence of late-emergent attention in all attention sources is confirmed.

The Effect of Documenting Patient Weight in Kilograms on Pediatric Medication Dosing Errors in Emergency Medical Services

Objectives: Up to 40% of children who receive a medication from emergency medical services (EMS) are subject to a dosing error. One of the reasons for this is difficulties adjusting dosages for weight. Converting weights from pounds to kilograms complicates this further. This is the rationale for the National EMS Quality Alliance measure Pediatrics-03b, which measures the proportion of children with a weight documented in kilograms. However, there is little evidence that this practice is associated with lower rates of dosing errors. Therefore, our objective was to determine whether EMS documentation of weight in kilograms was associated with a lower rate of pediatric medication dosing errors.Methods: We conducted a retrospective cross-sectional study of children 0-14 y/o in the 2016-17 electronic Maryland Emergency Medical Services Data System that received a weight-based medication. Using validated age-based formulas, we assigned a weight to patients without one documented. Doses were classified as errors and severe errors if they deviated from the state protocol by >20% or >50%, respectively. We compared the dosage errors in the two groups and completed secondary analyses for specific medications and age groups.Results: We identified 3,618 cases of medication administration, 53% of which had a documented weight. Patients with a documented weight had a significantly lower overall dose error rate than those without (22 vs. 26%, p<.05). A sensitivity analysis in which we assigned a weight to those patients with a weight recorded did not significantly change this result. Sub-analyses by individual medication showed that only epinephrine (34 vs. 56%, p<.05) and fentanyl (10 vs. 31%, p <.05) had significantly lower dosing error rates for patients with a documented weight. Infants were the only age group where documenting a weight was associated with a lower dosing error rate (33 vs. 53% p<.05).Conclusion: Our findings suggest that documenting a weight in kilograms is associated with a small but significantly lower rate of pediatric dosing errors by EMS. Documenting a weight in kilograms appears particularly important for specific medications and patient age groups. Additional strategies (including age-based standardized dosing) may be needed to further reduce pediatric dosing errors by EMS.

Factors associated with strong opioid use for noncancer pain in patients with chronic intestinal failure

BACKGROUND

Chronic analgesic use is described in home parenteral nutrition (HPN)-dependent patients, but there are limited data on factors associated with opioid use for noncancerous pain.

METHODS

Patients attending a national UK intestinal failure reference center were divided in two groups according to strong opioid (SO) usage; risk factors for SO usage were analyzed using logistic regression.

RESULTS

A total of 168 HPN-dependent patients were included. During the study period, 73 patients (43.5%) had documented SO usage (SO group), whereas the remainder did not (No-SO group). The prevalence of Crohn's disease among the No-SO group was twofold higher than among the SO group (43.2% vs 24.7%; P = 0.013), whereas those with surgical complications were twice as prevalent among the SO group (19.2% vs 8.4%, respectively; P = 0.04). The rate of working-age unemployment was significantly higher in the SO group (90.6%) than the No-SO group (55.6%; P = 0.001). Multivariate regression showed unemployment as an independent risk factor for SO usage (OR, 6.005; 95% CI, 1.435-25.134), whereas Crohn's disease (OR, 0.284; 95% CI, 0.09-0.898) and <4 intravenous support (IVS) nights per week (OR, 0.113; 95% CI, 0.012-1.009) were protective factors. The life-long incidence of catheter-related bloodstream infection (CRBSI) was comparable between groups (34.2% SO vs 27.4% No-SO; P = 0.336).

CONCLUSION

SO use is frequent among HPN-dependent patients and associated with high rates of unemployment and ≥4 IVS nights per week, but not with increased rate of CRBSI. The reduced usage among patients with Crohn's disease warrants further evaluation but might be due to the chronicity as compared with other IF etiologies.

Echocardiography Provides a Reliable Estimate of Total Cardiac Volume for Pediatric Heart Transplantation

BACKGROUND

Donor-to-recipient size matching for heart transplantation typically involves comparing donor and recipient body weight; however, weight is not linearly related to cardiac size. Attention has shifted toward the use of computed tomography- (CT-) derived total cardiac volume (TCV), that is, CT-TCV, to compare donor and recipient heart organ size. At this time, TCV size matching is near impossible for most centers due to logistical limitations. To overcome this impediment, echocardiogram-derived TCV (ECHO-TCV) is an attractive, alternative option to estimate CT-TCV. The goal of this study is to test whether ECHO-TCV is an accurate and reliable surrogate for TCV measurement compared with the gold standard CT-TCV.

METHODS

ECHO-TCV and CT-TCV were measured in a cohort spanning the neonatal to young adult age range with the intention to simulate the pediatric heart transplant donor pool. ECHO-TCV was measured using a modified Simpson's summation-of-discs method from the apical 4-chamber (A4C) view. The gold standard of CT-TCV was measured from CT scans using three-dimensional reconstruction software. The relationship between ECHO-TCV and CT-TCV was evaluated and compared with other anthropometric and image-based markers that may predict CT-TCV. Inter-rater reliability of ECHO-TCV was tested among 4 independent observers. Subanalyses were performed to identify imaging views and timing that enable greater accuracy of ECHO-TCV.

RESULTS

Banked imaging data of 136 subjects with both echocardiogram and CT were identified. ECHO-TCV demonstrated a linear relationship to CT-TCV with a Pearson correlation coefficient of r = 0.96 (95% CI, 0.95-0.97; P < .0001) and mean absolute percent error of 8.6%. ECHO-TCV correlated most strongly with CT-TCV in the subset of subjects <4 years of age (n = 33; r = 0.98; 95% CI, 0.96-0.99; P < .0001). The single-score intraclass correlation coefficient across all 4 raters is 0.96 (interquartile range, 0.93-0.98). ECHO-TCV measured from a standard A4C view at end diastole with the atria in the plane of view had the strongest correlation to CT-TCV.

CONCLUSIONS

ECHO-TCV by the A4C view was found to be both an accurate and reliable alternative measurement of CT-TCV and is derived from readily available donor ECHO images. The ECHO-TCV findings in this study make the ECHO method an attractive means of direct donor-to-recipient TCV size matching in pediatric heart transplantation.

Effects of membrane viscoelasticity on the red blood cell dynamics in a microcapillary

The mechanical properties of red blood cells (RBCs) play key roles in their biological functions in microcirculation. In particular, RBCs must deform significantly to travel through microcapillaries with sizes comparable with or even smaller than their own. Although the dynamics of RBCs in microcapillaries have received considerable attention, the effect of membrane viscoelasticity has been largely overlooked. In this work, we present a computational study based on the boundary integral method and thin-shell mechanics to examine how membrane viscoelasticity influences the dynamics of RBCs flowing through straight and constricted microcapillaries. Our results reveal that the cell with a viscoelastic membrane undergoes substantially different motion and deformation compared with results based on a purely elastic membrane model. Comparisons with experimental data also suggest the importance of accounting for membrane viscoelasticity to properly capture the transient dynamics of an RBC flowing through a microcapillary. Taken together, these findings demonstrate the significant effects of membrane viscoelasticity on RBC dynamics in different microcapillary environments. The computational framework also lays the groundwork for more accurate quantitative modeling of the mechanical response of RBCs in their mechanotransduction process in subsequent investigations.

Long-term survival following fungal catheter-related bloodstream infection for patients with intestinal failure receiving home parenteral support

BACKGROUND

A fungal-related catheter-related bloodstream infection (CRBSI) is less frequent than those induced by bacteria. In the past, a single episode of fungal CRBSI has been used as a marker of home parenteral nutrition (HPN) failure and thus a possible indication for intestinal transplantation.

METHODS

Survival outcomes were assessed from a prospectively maintained database of patients initiated on HPN for underlying chronic intestinal failure between 1993 and 2018, with a censoring date of December 31, 2020. Cox regression was performed to assess predictors of mortality with univariable and multivariable analysis.

RESULTS

A total of 1008 patients were included in the study, with a total of 1 364 595 catheter days. There were 513 CRBSI events recorded in 262 patients, equating to a CRBSI rate of 0.38/1000 catheter days. A total of 38/262 (14.5%) patients had at least one episode of fungal CRBSI, whereas 216/262 (82.4%) had at least one bacterial but no fungal CRBSI. The median time between HPN initiation and the first CRBSI episode was 20.6 months (95% confidence interval, 16.5-24.1). Episodes of fungal or bacterial CRBSI and the number of CRBSI episodes were not associated with increased mortality. Overall, 15 CRBSI-related deaths were observed in the observation period (0.01 CRBSI deaths/1000 catheter days), two of these were fungal in origin.

CONCLUSION

The occurrence of a fungal CRBSI does not increase the risk of death compared with patients who have bacterial CRBSI or those without a CRBSI event.

Routine ultrasound for suspected appendicitis in children: a single-centre retrospective cohort study

INTRODUCTION

Appendicitis continues to be a common surgical emergency in children, but its diagnosis remains challenging. Use of diagnostic imaging to confirm appendicitis has gained popularity in some countries because it is associated with lower negative appendicectomy rates. This study reports our centre's experience of adopting routine ultrasound for the investigation of suspected appendicitis in children.

METHODS

A single-centre retrospective cohort study was performed investigating all children aged 5-16 years admitted under surgeons with suspected appendicitis, in January-December 2019. Primary outcomes were the rate of ultrasound use, its accuracy in diagnosing/excluding appendicitis and negative appendicectomy rate. Other outcomes were treatment received, length of stay and complications.

RESULTS

The majority of the 193 children with suspected appendicitis underwent a diagnostic ultrasound (87.5%). Ultrasound was highly sensitive (0.90, 95% confidence interval (CI) 0.81-0.96) and specific (1.0, 95% CI 0.96-1.0) for appendicitis in this study. Negative appendicectomy rate was extremely low (1.4%). Laparoscopic appendicectomy was the preferred management (75/86), with one case started open and no conversions to open. A minority of cases of simple appendicitis (10/86) were treated primarily with antibiotics. Rates of complex appendicitis and postoperative complications were similar to other studies.

CONCLUSION

Ultrasound can be highly sensitive and specific for appendicitis. Its routine use to confirm appendicitis prior to surgery is associated with a low negative appendicectomy rate. This is a major change in practice for a general surgical unit in the United Kingdom.

Genomic analysis of the population structure of Paenibacillus larvae in New Zealand

New Zealand is a remote country in the South Pacific Ocean. The isolation and relatively late arrival of humans into New Zealand has meant there is a recorded history of the introduction of domestic species. Honey bees (Apis mellifera) were introduced to New Zealand in 1839, and the disease American foulbrood was subsequently found in the 1870s. Paenibacillus larvae, the causative agent of American foulbrood, has been genome sequenced in other countries. We sequenced the genomes of P. larvae obtained from 164 New Zealand apiaries where American foulbrood was identified in symptomatic hives during visual inspection. Multi-locus sequencing typing (MLST) revealed the dominant sequence type to be ST18, with this clonal cluster accounting for 90.2% of isolates. Only two other sequence types (with variants) were identified, ST5 and ST23. ST23 was only observed in the Otago area, whereas ST5 was limited to two geographically non-contiguous areas. The sequence types are all from the enterobacterial repetitive intergenic consensus I (ERIC I) genogroup. The ST18 and ST5 from New Zealand and international P. larvae all clustered by sequence type. Based on core genome MLST and SNP analysis, localized regional clusters were observed within New Zealand, but some closely related genomes were also geographically dispersed, presumably due to hive movements by beekeepers.

The cytopathic activity of cholera toxin requires a threshold quantity of cytosolic toxin

After binding to the surface of a target cell, cholera toxin (CT) moves to the endoplasmic reticulum (ER) by retrograde transport. In the ER, the catalytic CTA1 subunit dissociates from the rest of the toxin and is transferred to the cytosol where it is degraded by a ubiquitin-independent proteasomal mechanism. However, CTA1 persists long enough to induce excessive cAMP production through the activation of Gsα. It is generally believed that only one or a few molecules of cytosolic CTA1 are necessary to elicit a cytopathic effect, yet no study has directly correlated the levels of cytosolic toxin to the extent of intoxication. Here, we used the technology of surface plasmon resonance to quantify the cytosolic pool of CTA1. Our data demonstrate that only 4% of surface-bound CTA1 is found in the cytosol after 2 h of intoxication. This represented around 2600 molecules of cytosolic toxin per cell, and it was sufficient to produce a robust cAMP response. However, we did not detect elevated cAMP levels in cells containing less than 700 molecules of cytosolic toxin. Thus, a threshold quantity of cytosolic CTA1 is required to elicit a cytopathic effect. When translocation to the cytosol was blocked soon after toxin exposure, the pool of CTA1 already in the cytosol was degraded and was not replenished. The cytosolic pool of CTA1 thus remained below its functional threshold, preventing the initiation of a cAMP response. These observations challenge the paradigm that extremely low levels of cytosolic toxin are sufficient for toxicity, and they provide experimental support for the development of post-intoxication therapeutic strategies.

Radiotherapy for nasopharyngeal carcinoma: Effect on the eye 10 years later: A case report

A patient who had previously received radiotherapy for a nasopharyngeal carcinoma was rightfully discharged from otorhinolaryngology and oncology once treatment was completed. After 10 years, the patient presented with visual loss in one eye and was found to have radiation retinopathy. This case highlights the importance of recognising the effects that radiation administered to structures near the eye can have on vision. The latency of this case demonstrates the need for routine eye tests in patients who have undergone radiotherapy near the orbit. Prompt recognition and referral to ophthalmologists is necessary for all suspected cases to best manage visual loss.

The pediatric heart network's study on long-term outcomes of children with HLHS and the impact of Norwood Shunt type in the single ventricle reconstruction trial cohort (SVRIII): Design and adaptations

BACKGROUND

The Single Ventricle Reconstruction (SVR) Trial was the first randomized clinical trial of a surgical approach for treatment of congenital heart disease. Infants with hypoplastic left heart syndrome (HLHS) and other single right ventricle (RV) anomalies were randomized to a modified Blalock Taussig Thomas shunt (mBTTS) or a right-ventricular-to-pulmonary-artery shunt (RVPAS) at the time of the Norwood procedure. The aim of the Long-term Outcomes of Children with HLHS and the Impact of Norwood Shunt Type (SVR III) study is to compare early adolescent outcomes including measures of cardiac function, transplant-free survival, and neurodevelopment, between those who received a mBTTS and those who received an RVPAS.

METHODS

Transplant-free survivors of the SVR cohort were enrolled at 10 to 15 years of age for multifaceted in-person evaluation of cardiac function (cardiac magnetic resonance [CMR], echocardiogram and exercise test) and neurodevelopmental evaluation. Right ventricular ejection fraction measured by CMR served as the primary outcome. Development of arrhythmias, protein losing enteropathy, and other comorbidities were assessed through annual medical history interview. Through the course of SVR III, protocol modifications to engage SVR trial participants were designed to enhance recruitment and retention.

CONCLUSIONS

Evaluation of long-term outcomes will provide important data to inform decisions about the shunt type placed at the Norwood operation and will improve the understanding of cardiovascular and neurodevelopmental outcomes for early adolescents with HLHS.

EPCO-35. THE ZINC FINGER IN THE CEREBELLUM (ZIC1/4) LOCUS IS A CONTEXT DEPENDENT DRIVER GENE IN MEDULLOBLASTOMA

Medulloblastoma (MB) is a malignant paediatric brain tumor comprised of 4 molecularly and clinically distinct subgroups: WNT, SHH, Group 3 and Group 4. Previous studies have reported recurrent, mutually exclusive epigenetic modifier mutations converging in these subgroups, as well as aberrant H3K27me3 depositions within these tumors. While these observations hint at aberrant epigenetic mechanisms driving MB pathobiology, detailed understanding of MB chromatin landscape remains elusive to date. As such, chromatin landscape of MB was defined by conducting H3K27Ac ChIP-Seq in 102 primary MB tumors and H3K27me3 ChIP-Seq in 63 overlapping tumors. Chromatin landscape of Medulloblastoma was subgroup specific and H3K27me3 modification recurrently repressed ZIC1 in Group 3 and 4 MB, a driver gene that is also recurrently mutated within Group 4 and SHH MB. Validation cohort comprised of 251 MB samples with matching RNA-Seq and WGS data demonstrated that the ZIC1 - ZIC4 locus (ZIC1/4) undergoes recurrent epigenetic repression of single alleles in 25% of Group 3, 50% of Group 4 but rarely in other subgroups. Strikingly, ZIC1 mutations in the Group 4 tumors always occurred in the context of repression of the wildtype allele, revealing a recurrent convergence of genetic and epigenetic mechanisms targeting both copies of ZIC1. Overexpression of ZIC1 and ZIC4 together, or ZIC1 alone to a lesser extent, lead to reduced proliferation of Group 3 MB cells in vitro and in vivo. Intriguingly, while Group 4 ZIC1 mutations exhibited loss of function phenotypes, SHH ZIC1 mutations exhibited gain of function phenotypes. Overexpression of ZIC1 in Granule Progenitor Cells (GPC), which give rise to SHH MB, resulted in increased proliferation of cells in contrast to Group 3 MB cells. Taken together, we demonstrate that multiple epigenetic and genetic mechanisms converge to govern context dependent driver roles for ZIC1 and ZIC4 underlying MB pathobiology.

CSIG-34. LIN28B-LET-7-PBK PATHWAY IS AN IMPORTANT REGULATOR OF GROUP 3 MEDULLOBLASTOMA PROLIFERATION

Children with Group 3 medulloblastoma (MB) have a very poor long-term outcome and many do not survive beyond 5 years. Several drivers for Group 3 MB have been identified but none have resulted in targeted therapy to date. LIN28B is a stem cell factor upregulated in Group 3 MB and is associated with worse survival. Here we investigate the role of the LIN28B pathway in Group 3 MB development. Pharmacologic inhibition of the LIN28B pathway is feasible and may provide a unique opportunity to target this tumor. Using LIN28B knockdown and overexpression in Group 3 MB cells we test LIN28B’s effect on proliferation, self-renewal and metastasis. We investigate the effect of LIN28B knockdown on survival as well as proliferation and apoptosis markers using orthotopic xenografts in vivo. We also investigate the role of let-7 and its downstream target PBK on Group 3 MB proliferation. Finally, we use a LIN28 inhibitor 1632 and a PBK inhibitor HITOPK032 to treat Group 3 MB cell lines and then assess their impact on proliferation and apoptosis. We find that down-regulation of LIN28B or PBK using shRNA results in significant reduction in cell proliferation. In contrast overexpression of LIN28B increases Group 3 cell proliferation and tumor sphere formation. LIN28B knockdown also significantly (p&lt; 0.01) increases survival in mice with orthotopic Group 3 tumors. The LIN28 inhibitor 1632 also leads to significant reduction in MB growth through decreased cell cycle entry and increased apoptosis. In addition, HITOPK032 also demonstrates significant reduction in Group 3 MB cell proliferation at low micromolar concentration. We also demonstrate that HITOPK032 in combination with CDK 4/6 inhibition can additively inhibit proliferation of Group 3 MB cells. Our study establishes a critical role for the LIN28B-let-7-PBK pathway in Group3 MB and provides encouraging preliminary preclinical results for drugs that target this pathway.

DDDR-33. TARGETING TGFΒ PATHWAY DEPENDENCIES IN GROUP 3 MEDULLOBLASTOMA

Medulloblastoma (MB) is one of the most prevalent malignant brain tumors in children, with tremendous cognitive and neuroendocrine disability among survivors. Group 3 (G3) MBs have poor overall survival at &lt; 50%, few recurrent mutations, higher frequency of metastasis, and no targeted therapies. Amplification of MYC (c-myc) and activation of TGFβ signaling are frequent in G3 MB. We hypothesize that the TGFβ pathway and MYC contribute to the intrinsic resistance of G3 MB through deregulation of key genes and pathways. We previously established humanized models for SHH MB by introducing MYCN or PTCH1 deletions into neuroepithelial stem (NES) cells derived from normal human induced pluripotent stem cells (hIPSCs). In this study, we transduced NES cells with TGFb effectors activated in G3 MB (ACVR2A, TGFbR1, TGFb1, TGFb3, and SMAD5) alone and/or in combination with MYC, prioritizing combinations observed in patients. Excitingly, both MYC and TGFβ effectors drove tumor formation in vivo with the combination of TGFβ effectors with MYC leading to more aggressive tumors. We thus describe six new humanized isogenic models for both non-MYC and MYC driven G3 MB. We next found that NES cells expressing MYC with either TGFβR1 or TGFβ1 showed resistance to clinical TGFβR1 inhibitors, compared to cells driven by either TGFβR1 or TGFβ1 alone. To decipher mechanisms of resistance, we integrated CUT & RUN to probe for MYC genomic localization and relevant histone PTMs with RNA-seq analysis of MYC and TGFβ pathway driven NES cells. We discovered a subset of genes upregulated in MYC and TGFb-driven lines that are targets of the histone demethylase KDM2B. We postulate that epigenetic remodeling via MYC and recruitment of other MYC-interacting cofactors culminates in transcriptional changes that lead to aggressive disease. Overall, our studies provide insights on identifying new therapeutic avenues for patients with MYC and TGFβ driven G3 MB.

STEM-25. IN VIVO FUNCTIONAL GENOMICS IDENTIFIES ESSENTIALITY OF POTASSIUM HOMEOSTASIS IN MEDULLOBLASTOMA

Distinguishing cancer maintenance genes—i.e. genes essential and specific to tumor survival—from initiation, progression, and passenger genes is critical for developing effective cancer therapeutics. We engineered the Lazy Piggy genetic screening system, which uses a Sleeping Beauty / piggyBac hybrid transposon to dysregulate and later restore gene expression. In vivo spatiotemporal control of Lazy Piggy transposon insertion and remobilization depletes insertions that are non-essential for tumor survival while enriching for maintenance driver insertions. Using this functional genomic approach, we identify potassium channels as a regulator for medulloblastoma, the most common pediatric brain malignancy. Loss of potassium channel Kcnb2 diminishes the pool of medulloblastoma-propagating cells by hampering their replication potential, thereby prolonging the survival of tumor-bearing mice. Mechanistically, Kcnb2 governs potassium homeostasis to regulate plasma membrane tension-gated EGFR signaling, which drives the proliferative expansion of medulloblastoma-propagating cells. Our in vivo functional genomics reveals potassium homeostasis as a tumor maintenance essentiality, establishes a link between potassium channel activity and plasma membrane tension, and defines a mechanism by which ion homeostasis integrates biomechanical and biochemical signaling to promote medulloblastoma aggression.

EPCO-38. TYPE B ULTRA LONG-RANGE INTERACTIONS IN PFAS (TULIPS) ARE RECURRENT EPIGENOMIC FEATURES OF PFA EPENDYMOMA

Posterior Fossa Group A (PFA) ependymomas are pediatric brain tumors with extremely poor survival outcomes. As protein-coding mutations in PFA are exceedingly rare, the underlying etiology of these tumors remains elusive. Elevated CpG island methylation and depletion of H3K27me3 have been described in PFA, leading to the hypothesis that PFA may be driven by a dysregulated epigenetic state. In this study, we sought to determine how three-dimensional (3D) genome features (such as DNA loops, domains, and compartments) differ between pediatric brain tumors. We performed Hi-C sequencing on a collection of 64 patient specimens and patient-derived primary cultures that collectively span multiple subgroups of ependymoma, medulloblastoma, high-grade glioma, and non-neoplastic brain. For certain samples, we further performed RNA-seq, histone modification ChIP-seq, or whole-genome bisulfite sequencing to allow multiomic data integration. Overall, the 3D genome organization of PFA samples appeared distinct from other tumor types. We identified and defined TULIPs: a subset of type B compartments, separated by genomic distances greater than 10 Mbp, that exhibit a striking fivefold increase in reciprocal interaction strength. These TULIPs recurred at the same genomic positions across the vast majority of PFA samples with minimal representation among other tumor or non-tumor samples. TULIPs displayed enrichment for heterochromatic features such as H3K9me3 and late replication timing and were depleted of euchromatic features such as H3K27ac and protein-coding genes. By using immuno-fluorescence for H3K9me3 and oligo-FISH to label TULIP regions, we demonstrated that TULIP regions are more compact in PFA than other tumors. Finally, by applying inhibitors of H3K9 lysine methylation to PFA cultures we showed that TULIPs become more diffuse and cell viability is reduced. Altogether, this work defines TULIPs as highly recurrent epigenetic features of PFA tumors.

CSIG-28. THE HEDGEHOG GENE EXPRESSION PROGRAM REGULATES LIPID FEEDBACK MECHANISMS UNDERLYING HEDGEHOG-ASSOCIATED MEDULLOBLASTOMA

Misactivation of the Hedgehog pathway can cause cancers such as medulloblastomas, the most common malignant brain tumors in children. Hedgehog signals are transmitted through primary cilia, where Hedgehog ligands bind to Patched1 and activate Smoothened through interactions with cilia-associated sterol lipids. The gene expression programs driving cellular responses to ciliary Hedgehog signals are incompletely understood. Thus, to define Hedgehog target genes and elucidate mechanisms underlying Hedgehog-associated medulloblastomas, we performed RNA sequencing of cells after treatment with Hedgehog ligands (Shh, Dhh, Ihh), cilia-associated lipids (7b,27-dihydroxycholesterol, 24(S),25-epoxycholesterol), or synthetic lipids or small molecules that activate Smoothened (20(S)-hydroxycholesterol, SAG). Nonspecific gene expression changes were identified by performing RNA sequencing (1) after treatment of CRISPR mediated Smo-/- cells with the same Hedgehog pathway agonists, (2) after treatment with vehicle controls, or (3) after treatment with sterol lipids that are unable to activate Smoothened (7a,27-dihydroxycholesterol). Differentially expressed genes were integrated across RNA sequencing of human medulloblastomas (n=458) or the Math1-Cre SmoM2 mouse genetic model of Hedgehog-associated medulloblastoma. Mechanistic studies validating Hedgehog target genes were performed using CRISPR interference, genetic gain-of-function, molecular biology, quantitative immunofluorescence, or cell biology approaches. RNA sequencing after treatment with Hedgehog pathway agonists identified a core gene expression program comprised of 155 genes driving lipid synthesis, metabolism, signaling, adhesion, or angiogenesis. Integration of transcriptomic datasets revealed a conserved gene expression program driving cellular responses to ciliary Hedgehog signals in human or mouse medulloblastomas, including known target genes such as Gli1 or Ptch1, and novel target genes such as Hsd11b1 or Retnla. Retnla is a regulator of sterol synthase expression, and Hsd11b1 is a sterol synthase that opposes the action of Hsd11b2, a driver and druggable dependency underlying Hedgehog-associated medulloblastoma. In support of these findings, mechanistic studies demonstrated Retnla drives expression of Hsd11b2, and showed Hsd11b1 negatively regulates the Hedgehog pathway.

EXTH-79. HIJACKING A NEURODEVELOPMENTAL EPIGENOMIC PROGRAM IN METASTATIC DISSEMINATION OF MEDULLOBLASTOMA

Normal brain development relies on precise genetic and epigenetic spatiotemporal regulation of gene expression. How dysregulation of neurodevelopment relates to medulloblastoma, the most common pediatric brain tumor, remains elusive. Here, we uncovered a novel neurodevelopmental epigenomic program that regulates Purkinje cell migration in developing cerebellum is hijacked to induce tumor metastatic dissemination in medulloblastoma. Integrating publicly available datasets with our in-house data, unsupervised analyses revealed that BAF60C/SMARCD3, a subunit of SWI/SNF chromatin remodeling complex, promotes tumor cell migration in vitro and metastasis in vivo. Based on analyzing the single-cell RNAseq data of cerebellum developmental trajectory in mice and humans, aligning with the medulloblastoma patients’ datasets, we found that BAF60C/SMARCD3 regulated DAB1-mediated Reelin signaling is involved in Purkinje cell positioning during cerebellum development and medulloblastoma metastasis by orchestrating the cis-regulatory elements (CREs) at the DAB1 gene locus. Moreover, analysis of spatiotemporal gene expression and chromatin architecture in the human and mouse cerebellum demonstrated that transcription activity of the BAF60C/SMARCD3-DAB1 circuit is downregulated in a mature state of cerebellar development, however, is upregulated in metastatic medulloblastoma. We further identified that a core set of transcription factors, enhancer of zeste homolog 2 (EZH2) and nuclear factor I X (NFIX), bi-directionally control BAF60C/SMARCD3 transcriptional regulation by coordinating with the CREs at the BAF60C/SMARCD3 gene locus to form a chromatin hub during developing cerebellar development and medulloblastoma metastatic dissemination. Highly expressed BAF60C/SMARCD3 activates the Reelin/DAB1 signaling pathway downstream Src kinase, which was validated in the pair-wised primary and metastatic tumors from medulloblastoma patients. Preclinical medulloblastoma mouse models revealed that inhibiting Src activity reduces tumor cell migration and metastatic dissemination at a lower and safe dose. Together, these data deepen our understanding of how the developmental program influences disease progression and provide an opportunity for the development of therapeutics for this devastating brain cancer in children.

Standardised survival and excess Life Years Lost in patients with type 3 intestinal failure

BACKGROUND & AIMS

Long term outcomes have been reported in home parenteral nutrition (HPN)-dependent patients with type 3 intestinal failure (IF), but there are limited survival data standardised to the general population that would help provide a meaningful prognosis for patients and clinicians. The primary aim of this study was therefore to investigate the survival of HPN-dependent patients and to evaluate the specific impact of type 3 IF on their life expectancy standardised to that of the general population.

METHODS

This was a cohort study of adult patients initiated on HPN between 1978 and 2018 at a national UK IF reference centre and followed up until death or censoring date of 31st December 2020. The standardised mortality ratio (SMR) was calculated as observed deaths divided by expected deaths using UK Office for National Statistics database. Excess Life Years Lost (LYL) were calculated separately for each sex as the differences in average life expectancy between patients with type 3 IF and the general population. Survival data were evaluated using cox regression models adjusting for confounding.

RESULTS

In total, 1046 patients were identified, with a total observation time of 7344.1 patient-years. Patients with malignancy (n = 206) were excluded from the survival analysis. Of the remaining 840 patients, 398 were alive by the end of follow-up. The probability of survival was 91.8% at 1 year, 69.3% at 5 years, 54.3% at 10 years, 29.8% at 20 years and 16.7% at 30 years. Patients who did not achieve nutritional autonomy had an increased likelihood of death compared to patients who ceased HPN. In total, 40 (9.0%) deaths were HPN or IF-related, while underlying disease leading to IF accounted for 98 (22.2%) deaths. There were 270 (61.1%) deaths not related to IF, with the majority of these patients dying from infections unrelated to HPN. Overall mortality rates were higher among patients with a diagnosis of type 3 IF compared with the general UK population with a SMR of 7.48 (95% CI 6.80 to 8.21) and an excess mortality rate of 54.0 per 1000 person-years. All mechanisms of IF were associated with excess mortality, with SMR ranging from 6.82 (95% CI 5.98 to 7.72) for short bowel syndrome to 15.51 (95% CI 11.73 to 20.03) for dysmotility. On average, the excess LYL was 17.45 years for males and 17.39 years for females compared with the general population of the same age.

CONCLUSION

This the largest single-centre series reporting survival outcomes in patients with type 3 IF over more than a four-decade period and the first to report LYL in this patient cohort. Type 3 IF was associated with more than seven-fold higher mortality rates than for the general UK population and shorter life expectancies of more than 17 years. Survival, however, was better in those able to achieve nutritional autonomy. Since the majority of deaths were due to non-HPN or non-IF causes, there is clearly a need now to further explore these causes of death in order to improve our understanding of excessive mortality in type 3 IF and develop ways to prevent it.

Prognostic prediction of genotype versus phenotype in genetic cardiomyopathies

Background

In cardiomyopathies (CMPs), the diverse genetic background often leads to phenotypic heterogeneity. Currently, genotype-phenotype studies are founded on clinical phenotype-based classification of CMPs, contributing possible biases due to the exclusion of specific and unascertained phenotypic expressions of CMP genes.

Purpose

We sought to define differences in outcome when stratifying patients based on phenotype at presentation compared with genotype in a large cohort of CMP patients with positive genetic testing.

Methods

In this study, we included the whole spectrum of non-hypertrophic CMP phenotypes, genetically determined: dilated cardiomyopathy (DCM), arrhythmogenic right ventricular cardiomyopathy (ARVC), left ventricular arrhythmogenic cardiomyopathy (ALVC) and biventricular ARVC (BiV). The primary and secondary outcomes were: 1) all-cause mortality/heart transplant (D/HT); 2) heart failure-related death/heart transplant/left ventricular assist device implantation (DHF/HT/VAD); and 3) sudden cardiac death/life-threatening ventricular arrhythmias (SCD/MVA).

Results

Two hundred and eighty-one patients (80% DCM) carrying pathogenic or likely pathogenic variants were included in this study. The phenotype was classified as DCM, ARVC, ALVC and BiV according to current consensus criteria. The median follow-up was 188 months. Variants in titin (TTN; 34%) and sarcomeric genes (SARC; 22%) were the most frequent genotypes and almost invariably associated with a DCM phenotype. DSP, LMNA and FLNC displayed more heterogeneous phenotypic presentations, including DCM, ARVC, ALVC, BiV. At survival analysis, the arrhythmic outcome occurred more frequently in patients without a DCM phenotype and in carriers of DSP, PKP2, LMNA and FLNC variants. However, after adjustment for age and sex, the genotype-based classification but not the phenotype-based classification was predictive of the arrhythmic outcome. LMNA showed the worst trend in term of D/HT and DHF/HT/LVAD.

Conclusions

In genetic cardiomyopathies, genotype is associated with significant phenotypic heterogeneity. Nevertheless, in our study, the genotypic-based classification showed higher precision in predicting CMP patients' outcome in respect to the phenotype-based classification. These findings add to the current understanding of inherited CMPs and may implement the risk stratification of patients with positive genetic testing.

Funding Acknowledgement

Type of funding sources: None.

Injectable carbon nanotube-functionalized hydrogel as a tool for cardiac tissue engineering

Background/Introduction

Heart failure (HF) is an expensive major public health problem in the United States and around the world (1). The current treatments for HF are aimed at reducing symptoms, slowing disease progression, and reducing mortality and not aimed at repairing heart muscle or restoring function. Furthermore, even with these treatments, approximately half of patients with HF will die within 5 years of diagnosis (2). Cardiac transplantation remains the only definitive treatment for those affected with end-stage HF, but availability of donor hearts remains a major limitation (3).

Purpose

The ability of the adult heart to regenerate cardiomyocytes (CMs) lost after injury is limited, generating interest in developing tissue engineering therapies to avoid progression towards HF. Rigid carbon nanotubes (CNTs) scaffolds have been used to improve CMs viability, proliferation, and maturation (4), but require undesirable invasive surgeries for implantation. To overcome this limitation, we engineered an injectable reverse thermal gel (RTG) functionalized with CNTs (RTG-CNT) that transitions from a liquid-solution to a gel-based matrix shortly after reaching body temperature allowing for a liquid-based delivery rapidly followed by a stable-gel localization (5).

Methods and results

Here we show experimental evidences the RTG-CNT hydrogel, used as a three-dimensional (3D) niche to culture human induced pluripotent stem cells (hiPSC)-CMs, promotes hiPSC-CMs alignment and elongation with increased Cx43 localization and improved contraction function when compared with traditional two-dimensional (2D) fibronectin controls and plain 3D RTG system without CNTs. Moreover, the short-term (4-week) biocompatibility of the RTG-CNT hydrogel was also assessed in a mouse model (intracardial injection). The results confirmed that the RTG-CNT hydrogel is well tolerated by the cardiac tissue.

Conclusion

Our results indicated that the injectable RTG-CNT hydrogel has the potential to be used as a minimally invasive tool for cardiac tissue engineering efforts.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): NATIONAL HEART, LUNG, AND BLOOD (NHLBI) INSTITUTE

Knowledge transfer of eLearning objects: Lessons learned from an intercontinental capacity building project

Background

Effective knowledge transfer of eLearning objects can hasten the adoption and dissemination of technology in teaching and learning. However, challenges exist which hinder inter-organisational knowledge transfer, particularly across continents. The ACoRD project aimed to transfer knowledge on digital learning development from UK/EU (provider) to Malaysian (receiver) higher education institutions (HEIs). This study explores the challenges encountered during the knowledge transfer process and lessons learned.

Methods

This is a qualitative study involving both the knowledge providers and receivers in focus group discussions (n = 25). Four focus group discussions were conducted in the early (n = 2) and mid-phase (n = 2) of the project by trained qualitative researchers using a topic guide designed to explore experiences and activities representing knowledge transfer in multi-institutional and multi-cultural settings. The interviews were audio-recorded, transcribed verbatim, and checked. The transcripts were analysed using thematic analysis.

Results

Five main themes emerged from this qualitative study: mismatched expectations between providers and receivers; acquiring new knowledge beyond the professional "comfort zone"; challenges in cascading newly acquired knowledge to colleagues and management; individual and organisational cultural differences; and disruption of knowledge transfer during the COVID-19 pandemic.

Conclusion

This study highlights the need to create a conducive platform to facilitate continuous, timely and bi-directional needs assessment and feedback; this should be done in the early phase of the knowledge transfer process. The challenges and strategies identified in this study could guide more effective knowledge transfer between organisations and countries.

Home Parenteral Nutrition in Patients with Advanced Cancer: Quality Outcomes from a Centralized Model of Care Delivery

Lack of expertise in home parenteral nutrition (HPN) management has been reported as a barrier to its initiation in patients with advanced cancer (AC), and there are limited data describing hospital readmissions and HPN-related complications. We aimed to assess a centralized approach for managing HPN in AC and evaluate associated outcomes, including hospital readmissions and HPN-related complications. This was a cohort study of adults with AC requiring palliative HPN between 2010–2018 at a tertiary intestinal failure (IF) center, primarily utilizing a centralized model of HPN oversight to discharge patients remotely from an oncology center to their homes over a wide geographic area. A total of 126 patients were included, with a median distance between the patient’s home and the IF center of 17.5 km (IQR 10.9–39.1; maximum 317.4 km). A total of 28 (22%) patients experienced at least one HPN-related complication, the most common being a central venous catheter (CVC) occlusion and electrolyte abnormalities. The catheter-related bloodstream infection (CRBSI) rate was 0.49/1000 catheter days. The CVC type, administration of concomitant chemotherapy via a distinct CVC lumen separate from PN, venting gastrostomy and distance between the patient’s home and the IF center were not associated with CRBSI or mechanical CVC complications. A total of 82 (65.1%) patients were readmitted while on HPN, but only 7 (8.5%) of these readmissions were HPN-related. A total of 44 (34.9%) patients died at home, 41 (32.5%) at a hospice and 41 (32.5%) in a hospital. In conclusion, this study demonstrates that a centralized approach to IF care can provide HPN to patients over a large geographical area while maintaining low HPN-related complications that are comparable to patients requiring HPN for benign conditions and low hospital readmission rates.

Preservation of endocrine function after Ommaya reservoir insertion in children with cystic craniopharyngioma

INTRODUCTION

Children with craniopharyngiomas (CP) can experience significant morbidities caused by extensive surgery and/or radiation. Ommaya reservoir insertion (ORI) into cystic CP represents a minimally invasive approach allowing immediate decompression and aims to avoid additional injuries. The purpose of this study was to determine the surgical outcome and relevance of upfront ORI (± intracystic treatment) for preservation of endocrine function.

METHODS

We performed a retrospective chart review of children with CP treated at the Hospital for Sick Children between 01/01/2000 and 15/01/2020. Endocrine function was reviewed at the time of initial surgery and throughout follow-up. New endocrinological deficits related to the index procedure were defined as immediate failure (IF), whereas postoperative duration of endocrinological stability (ES) was analyzed using the Kaplan-Meier method. The rate of IF and ES was compared between the treatment groups.

RESULTS

Seventy-nine patients were included and had a median age of 8.3 years (range 2.1-18.0 years); 31 were males. Fifty-three patients with upfront surgical treatment, including 29 ORI and 24 gross total or partial resections had sufficient endocrinological follow-up data. Endocrine dysfunction occurring immediately after the index procedure (IF) was observed in 15 patients (62.5%) in the resection group compared to two patients (6.8%) in the ORI group, odds ratio: 0.05 (CI: 0.01-0.26, p < 0.0001). Excluding those with immediate endocrinological deficits, mean ES after ORI was 19.4 months (CI: 11.6-34.2), compared to 13.4 months (CI:10.6-NA) after surgical resection.

CONCLUSIONS

Endocrine function was preserved in patients with upfront ORI (± intracystic treatment), which was confirmed as a minimally invasive procedure with an overall low morbidity profile.