A First-in-Class, Highly Selective and Cell-Active Allosteric Inhibitor of Protein Arginine Methyltransferase 6.

Protein arginine methyltransferase 6 (PRMT6) catalyzes monomethylation and asymmetric dimethylation of arginine residues in various proteins, plays important roles in biological processes, and is associated with multiple cancers. To date, a highly selective PRMT6 inhibitor has not been reported. Here we report the discovery and characterization of a first-in-class, highly selective allosteric inhibitor of PRMT6, (R)-2 (SGC6870). (R)-2 is a potent PRMT6 inhibitor (IC50 = 77 ± 6 nM) with outstanding selectivity for PRMT6 over a broad panel of other methyltransferases and nonepigenetic targets. Notably, the crystal structure of the PRMT6-(R)-2 complex and kinetic studies revealed (R)-2 binds a unique, induced allosteric pocket. Additionally, (R)-2 engages PRMT6 and potently inhibits its methyltransferase activity in cells. Moreover, (R)-2's enantiomer, (S)-2 (SGC6870N), is inactive against PRMT6 and can be utilized as a negative control. Collectively, (R)-2 is a well-characterized PRMT6 chemical probe and a valuable tool for further investigating PRMT6 functions in health and disease.

Correlation of Pulmonary Function to Novel Radiographic Parameters of Collapsing Parasol Deformity in Spinal Muscular Atrophy.

Spinal muscular atrophy (SMA) is a neuromuscular disease with manifestations of scoliosis, pulmonary function decline, and, uniquely, collapse of the ribs. Methods to quantify rib deformity and its impact on pulmonary function are sparse. The authors propose new radiographic measurements to quantify the aspect of SMA known as collapsing parasol deformity and correlate these measurements with pulmonary function. Twenty-eight full-spine radiographs of pediatric SMA patients were measured twice by 3 independent investigators, with 2 weeks separating each measurement. Radiographic measurements, demographics, spirometry results, and assisted ventilation rating were obtained. Twenty-one patients with spirometry metrics were assessed to correlate pulmonary function and spinal measurements. The intrarater intraclass correlation coefficient (ICC) for the measurements ranged from 0.706 to 0.99, and the interrater ICC ranged from 0.64 to 0.97. Eighteen of 19 variables had ICC values greater than 0.75 for inter- and intrarater reliability. Twenty-one patients with forced expiratory volume in 1 second and forced vital capacity were assessed in terms of these measurements. Ratio of the concave hemithoracic width at T6/convex hemithoracic width at T6 (P=.004) and ratio of convex vertical rib displacement at the apical rib/concave vertical rib displacement (P=.021) were both significantly correlated with decreased pulmonary function. No significant correlation was found examining the average vertical rib displacement at the apical rib. High inter-and intrarater reliability can be obtained in a variety of spinal measurements of SMA patients. Various measurements are correlated to diminished pulmonary function, specifically variables showing asymmetric changes in the chest cavity. [Orthopedics. 2021;44(2):e287-e293.].

Understanding Respiratory Restrictions as a Function of the Scoliotic Spinal Curve in Thoracic Insufficiency Syndrome: A 4D Dynamic MR Imaging Study.

BACKGROUND: Over the past 100 years, many procedures have been developed for correcting restrictive thoracic deformities which cause thoracic insufficiency syndrome. However, none of them have been assessed by a robust metric incorporating thoracic dynamics. In this paper, we investigate the relationship between radiographic spinal curve and lung volumes derived from thoracic dynamic magnetic resonance imaging (dMRI). Our central hypothesis is that different anteroposterior major spinal curve types induce different restrictions on the left and right lungs and their dynamics. METHODS: Retrospectively, we included 25 consecutive patients with thoracic insufficiency syndrome (14 neuromuscular, 7 congenital, 4 other) who underwent vertical expandable prosthetic titanium rib surgery and received preimplantation and postimplantation thoracic dMRI for clinical care. We measured thoracic and lumbar major curves by the Cobb measurement method from anteroposterior radiographs and classified the curves as per Scoliosis Research Society (SRS)-defined curve types. From 4D dMRI images, we derived static volumes and tidal volumes of left and right lung, along with left and right chest wall and left and right diaphragm tidal volumes (excursions), and analyzed their association with curve type and major curve angles. RESULTS: Thoracic and lumbar major curve angles ranged from 0 to 136 and 0 to 116 degrees, respectively. A dramatic postoperative increase in chest wall and diaphragmatic excursion was seen qualitatively. All components of volume increased postoperatively by up to 533%, with a mean of 70%. As the major curve, main thoracic curve (MTC) was associated with higher tidal volumes (effect size range: 0.7 to 1.0) than thoracolumbar curve (TLC) in preoperative and postoperative situation. Neither MTC nor TLC showed any meaningful correlation between volumes and major curve angles preoperatively or postoperatively. Moderate correlations (0.65) were observed for specific conditions like volumes at end-inspiration or end-expiration. CONCLUSIONS: The relationships between component tidal volumes and the spinal curve type are complex and are beyond intuitive reasoning and guessing. TLC has a much greater influence on restricting chest wall and diaphragm tidal volumes than MTC. Major curve angles are not indicative of passive resting volumes or tidal volumes. LEVEL OF EVIDENCE: Level II-diagnostic.

Genetic testing and cascade screening in pediatric long QT syndrome and hypertrophic cardiomyopathy.

BACKGROUND: The efficacy of cascade screening for the inherited heart conditions long QT syndrome (LQTS) and hypertrophic cardiomyopathy (HCM) is incompletely characterized. OBJECTIVE: The purpose of this study was to examine the use of genetic testing and yield of cascade screening across diverse regions in the United States and to evaluate obstacles to screening in multipayer systems. METHODS: An institutional review board-approved 6 United States pediatric center retrospective chart review of LQTS and HCM patients from 2008-2014 was conducted for (1) genetic test completion and results and (2) family cascade screening acceptance, methods, results, and barriers. RESULTS: The families of 315 index patients (mean age 9.0 ± 5.8 years) demonstrated a 75% (254) acceptance of cascade screening. The yield of relative screening was 39% (232/601), an average of 0.91 detected per family. Genetic testing was less utilized in HCM index patients and relatives. Screening participation was greater in families of gene-positive index patients (88%) (P <.001) compared to gene-negative patients (53%). Cascade method utilization: Cardiology-only 45%, combined genetic and cardiology 39%, and genetic only 16%. Screening yield by method: combined 57%, genetic-only 29%, and cardiology-only 20%. Family decisions were the leading barriers to cascade screening (26% lack of followthrough and 26% declined), whereas insurance (6%) was the least cited barrier. CONCLUSION: Family participation in cascade screening is high, but the greatest barriers are family mediated (declined, lack of followthrough). Positive proband genetic testing led to greater participation. Cardiology-only screening was the most utilized method, but combined cardiology and genetic screening had the highest detection.

Can We Save the Implant: Rib-based Implant Removal Rates and Risk Factors Following Irrigation and Debridement (I&D) Surgery?

BACKGROUND: In the event of a surgical site infection, management includes surgical debridement in an attempt to treat the infection and retain the implant; however they are often unsuccessful in this regard. Although studies have described the incidence of complications, current literature does not have sufficient evidence to provide clear recommendations regarding retention versus removal of implants. This study aims to identify predictive factors associated with the need for implant removal to decrease unnecessary attempts at implant retention. METHODS: A retrospective review of early-onset scoliosis patients at a single institution treated with rib-based vertical expandable prosthetic titanium rib implants who developed infection requiring irrigation and debridement (I&D) due to wound problems including surgical site infection, skin slough, and wound dehiscence. All patients had a minimum of a 2-year follow-up. Univariate and multivariate logistic regression analyses were conducted to determine the odds of implant removal. RESULTS: Fifty-nine of 181 patients (32%) required an I&D due to a wound problem. These patients underwent the initial implant procedure at a mean age of 4.6±3.8 years. In total, 29 patients ultimately underwent implant removal. Significant predictive factors for removal included total number of wound problems, total number of I&Ds, days from identification of wound problem to I&D procedure, days on antibiotics, total number of surgeries, presence of gastrostomy tube, and nonambulatory status (P<0.0001, 0.001, 0.095, 0.093, 0.082, 0.054, and 0.026, respectively). Multiple logistic regression results indicated a total number of wound problems [odds ratio (OR): 6.00, P=0.001], average days from identification of wound problem to I&D (OR: 1.03, P=0.039), and presence of a gastrostomy tube (OR: 5.7, P=0.07) as independent predictors for implant removal. CONCLUSIONS: Data suggests that time from the onset of signs of infection until debridement surgery inversely correlates with the ability to retain the implants. In addition, gastrostomy tube and history of previous wound infections may be predictive clinical factors for implant removal in patients with a rib-based vertical expandable prosthetic titanium rib instrumentation. Such information can be useful for clinicians in deciding on whom to attempt implant retention versus removal when a wound problem presents itself. LEVEL OF EVIDENCE: Level III.

Comprehensive Wound Risk Stratification of Rib-Based Distraction Instrumentation Procedures.

STUDY DESIGN: Single-center retrospective analysis of a prospectively collected registry. OBJECTIVES: Identify factors predictive of rib-based distraction (RBD) instrumentation wound complication. Create a risk stratification model for RBD instrumentation wound complication. SUMMARY OF BACKGROUND DATA: RBD instrumentation procedures have a high rate of wound complications, often requiring unplanned operative treatment. Currently, there is a relative lack of understanding of RBD complication risk factors compared with the comprehensive understanding of complication risk factors for other spine surgeries. METHODS: Between January 2011 and September 2015, patients treated with RBD instrumentation at a single institution were analyzed for risk factors associated with surgical wound complications that resulted in unplanned operative treatment. Univariate logistic regression determined predictors of wound complication and multivariate regression determined independent predictive factors; α = 0.10. RESULTS: A total of 122 patients aged 0-18 years underwent 140 implant surgeries in which 22 resulted in complications: 18 (82%) infectious and 4 (18%) noninfectious. Mean age at surgery was 5.2 years. Univariate analysis showed a correlation between wound complication rates and the following: male gender (p = .097), diapered patient with lower back incision (p = .004), bilateral procedure (p = .008), more than three incisions (p = .011), left iliac incision (p = .097), right iliac incision (p = .009), patient age ≤4 years (p = .10), and operative time >150 minutes (p = .079). Multivariate analysis identified the following independent predictors: age ≤ 4 years (p = .002), male gender (p = .04), number of skin incisions (p = .001), left iliac incision (p = .018), and nutritionally challenged (p = .044). The multivariate model predicted wound complications with an area under the receiver operating characteristic curve of 0.88. CONCLUSIONS: Knowledge of risk factors for RBD instrumentation wound complications can be used to construct patient risk models. This can identify patients at higher risk for complications and influence clinical decision making. LEVEL OF EVIDENCE: Level II.

Aurora A-Selective Inhibitor LY3295668 Leads to Dominant Mitotic Arrest, Apoptosis in Cancer Cells, and Shows Potent Preclinical Antitumor Efficacy.

Although Aurora A, B, and C kinases share high sequence similarity, especially within the kinase domain, they function distinctly in cell-cycle progression. Aurora A depletion primarily leads to mitotic spindle formation defects and consequently prometaphase arrest, whereas Aurora B/C inactivation primarily induces polyploidy from cytokinesis failure. Aurora B/C inactivation phenotypes are also epistatic to those of Aurora A, such that the concomitant inactivation of Aurora A and B, or all Aurora isoforms by nonisoform-selective Aurora inhibitors, demonstrates the Aurora B/C-dominant cytokinesis failure and polyploidy phenotypes. Several Aurora inhibitors are in clinical trials for T/B-cell lymphoma, multiple myeloma, leukemia, lung, and breast cancers. Here, we describe an Aurora A-selective inhibitor, LY3295668, which potently inhibits Aurora autophosphorylation and its kinase activity in vitro and in vivo, persistently arrests cancer cells in mitosis, and induces more profound apoptosis than Aurora B or Aurora A/B dual inhibitors without Aurora B inhibition-associated cytokinesis failure and aneuploidy. LY3295668 inhibits the growth of a broad panel of cancer cell lines, including small-cell lung and breast cancer cells. It demonstrates significant efficacy in small-cell lung cancer xenograft and patient-derived tumor preclinical models as a single agent and in combination with standard-of-care agents. LY3295668, as a highly Aurora A-selective inhibitor, may represent a preferred approach to the current pan-Aurora inhibitors as a cancer therapeutic agent.

Site-specific Surgical Site Infection Rates for Rib-based Distraction.

BACKGROUND: Implantable rib-based distraction devices have revolutionized the treatment of children with early onset scoliosis and thoracic insufficiency syndrome. Unfortunately, the need for multiple skin incisions and repeated surgeries in a fragile patient population creates considerable infection risk. In order to assess rates of infection for different incision locations and potential risk factors, we generated a prospectively collected database of patients treated with rib-based distraction devices. METHODS: We analyzed a cohort of patients with thoracic insufficiency syndrome from various etiologies that our institution treated with rib-based distraction devices from 2013 to 2016. Surgery type (implantation, expansion, revision/removal), and surgeon adjudicated surgical site infection (SSI) were collected. For this study, we developed a novel, rib-based distraction device surgical site labeling system in which incisions could be labeled as either proximal or distal surgical exposure areas. Treating surgeons documented the operative site, procedure, and SSI site in real-time. RESULTS: A total of 166 unique patients underwent 670 procedures during the study period, producing 1537 evaluable surgical sites; 1299 proximal and 238 distal. Patients were 6.81±4.0 years of age on average. Forty-seven procedures documented SSIs (7.0%), while 40 (24.1%) patients experienced an infection. Analysis showed significant variation in the rate of infection between implantation, and expansion, and revision procedures, with implantation procedures having the highest infection rate at 13.1% (P<0.01). Infections occurred more frequently at distal sites than proximal ones (P=0.02). CONCLUSIONS: Our novel, surgeon-entered, prospective quality improvement database has identified distal surgical sites as being at higher risk for SSI than proximal ones. Further, rib-based distraction device implantation procedures were identified as being at a greater risk for SSI than expansion or revision procedures. We believe this data can lead to improved prevention measures, anticipatory guidance, and patient care. LEVEL OF EVIDENCE: Level II-prognostic study.

Chemotherapy-Induced Distal Enhancers Drive Transcriptional Programs to Maintain the Chemoresistant State in Ovarian Cancer.

Chemoresistance is driven by unique regulatory networks in the genome that are distinct from those necessary for cancer development. Here, we investigate the contribution of enhancer elements to cisplatin resistance in ovarian cancers. Epigenome profiling of multiple cellular models of chemoresistance identified unique sets of distal enhancers, super-enhancers (SE), and their gene targets that coordinate and maintain the transcriptional program of the platinum-resistant state in ovarian cancer. Pharmacologic inhibition of distal enhancers through small-molecule epigenetic inhibitors suppressed the expression of their target genes and restored cisplatin sensitivity in vitro and in vivo. In addition to known drivers of chemoresistance, our findings identified SOX9 as a critical SE-regulated transcription factor that plays a critical role in acquiring and maintaining the chemoresistant state in ovarian cancer. The approach and findings presented here suggest that integrative analysis of epigenome and transcriptional programs could identify targetable key drivers of chemoresistance in cancers. SIGNIFICANCE: Integrative genome-wide epigenomic and transcriptomic analyses of platinum-sensitive and -resistant ovarian lines identify key distal regulatory regions and associated master regulator transcription factors that can be targeted by small-molecule epigenetic inhibitors.

Increased complications without neurological benefit are associated with prophylactic spinal cord untethering prior to scoliosis surgery in children with myelomeningocele.

PURPOSE: Children with myelomeningocele (MMC) are at increased risk of developing neuromuscular scoliosis and spinal cord re-tethering (Childs Nerv Syst 12:748-754, 1996; Neurosurg Focus 16:2, 2004; Neurosurg Focus 29:1, 2010). Some centers perform prophylactic untethering on asymptomatic MMC patients prior to scoliosis surgery because of concern that additional traction on the cord may place the patient at greater risk of neurologic deterioration peri-operatively. However, prophylactic untethering may not be justified if it carries increased surgical risks. The purpose of this study was to determine if prophylactic untethering is necessary in asymptomatic children with MMC undergoing scoliosis surgery. METHODS: A multidisciplinary, retrospective cohort study from seven children's hospitals was performed including asymptomatic children with MMC < 21 years old, managed with or without prophylactic untethering prior to scoliosis surgery. Patients were divided into three groups for analysis: (1) untethering at the time of scoliosis surgery (concomitant untethering), (2) untethering within 3 months of scoliosis surgery (prior untethering), and (3) no prophylactic untethering. Baseline data, intra-operative reports, and 90-day post-operative outcomes were analyzed to assess for differences in neurologic outcomes, surgical complications, and overall length of stay. RESULTS: A total of 208 patients were included for analysis (mean age 9.4 years, 52% girls). No patient in any of the groups exhibited worsened motor or sensory function at 90 days post-operatively. However, comparing the prophylactic untethering groups with the group that was not untethered, there was an increased risk of surgical site infection (SSI) (31.3% concomitant, 28.6% prior untethering vs. 12.3% no untethering; p = 0.0104), return to the OR (43.8% concomitant, 23.8% prior untethering vs. 17.4% no untethering; p = 0.0047), need for blood transfusion (51.6% concomitant, 57.1% prior untethering vs. 33.8% no untethering; p = 0.04), and increased mean length of stay (LOS) (13.4 days concomitant, 10.6 days prior untethering vs. 6.8 days no untethering; p < 0.0001). In multivariable logistic regression analysis, prophylactic untethering was independently associated with increased adjusted relative risks of surgical site infection (aRR = 2.65, 95% CI 1.17-5.02), unplanned re-operation (aRR = 2.17, 95% CI 1.02-4.65), and any complication (aRR = 2.25, 95% CI 1.07-4.74). CONCLUSION: In this study, asymptomatic children with myelomeningocele who underwent scoliosis surgery developed no neurologic injuries regardless of prophylactic untethering. However, those who underwent prophylactic untethering were more likely to experience SSIs, return to the OR, need a blood transfusion, and have increased LOS than children not undergoing untethering. Based on these data, prophylactic untethering in asymptomatic MMC patients prior to scoliosis surgery does not provide any neurological benefit and is associated with increased surgical risks.

Aurora A Kinase Inhibition Is Synthetic Lethal with Loss of the RB1 Tumor Suppressor Gene.

Loss-of-function mutations in the retinoblastoma gene RB1 are common in several treatment-refractory cancers such as small-cell lung cancer and triple-negative breast cancer. To identify drugs synthetic lethal with RB1 mutation (RB1 mut), we tested 36 cell-cycle inhibitors using a cancer cell panel profiling approach optimized to discern cytotoxic from cytostatic effects. Inhibitors of the Aurora kinases AURKA and AURKB showed the strongest RB1 association in this assay. LY3295668, an AURKA inhibitor with over 1,000-fold selectivity versus AURKB, is distinguished by minimal toxicity to bone marrow cells at concentrations active against RB1 mut cancer cells and leads to durable regression of RB1 mut tumor xenografts at exposures that are well tolerated in rodents. Genetic suppression screens identified enforcers of the spindle-assembly checkpoint (SAC) as essential for LY3295668 cytotoxicity in RB1-deficient cancers and suggest a model in which a primed SAC creates a unique dependency on AURKA for mitotic exit and survival. SIGNIFICANCE: The identification of a synthetic lethal interaction between RB1 and AURKA inhibition, and the discovery of a drug that can be dosed continuously to achieve uninterrupted inhibition of AURKA kinase activity without myelosuppression, suggest a new approach for the treatment of RB1-deficient malignancies, including patients progressing on CDK4/6 inhibitors.See related commentary by Dick and Li, p. 169.This article is highlighted in the In This Issue feature, p. 151.

LLY-283, a Potent and Selective Inhibitor of Arginine Methyltransferase 5, PRMT5, with Antitumor Activity.

Protein arginine methyltransferase 5 (PRMT5) is a type II arginine methyltransferase that catalyzes the formation of symmetric dimethylarginine in a number of nuclear and cytoplasmic proteins. Although the cellular functions of PRMT5 have not been fully unraveled, it has been implicated in a number of cellular processes like RNA processing, signal transduction, and transcriptional regulation. PRMT5 is ubiquitously expressed in most tissues and its expression has been shown to be elevated in several cancers including breast cancer, gastric cancer, glioblastoma, and lymphoma. Here, we describe the identification and characterization of a novel and selective PRMT5 inhibitor with potent in vitro and in vivo activity. Compound 1 (also called LLY-283) inhibited PRMT5 enzymatic activity in vitro and in cells with IC50 of 22 ± 3 and 25 ± 1 nM, respectively, while its diastereomer, compound 2 (also called LLY-284), was much less active. Compound 1 also showed antitumor activity in mouse xenografts when dosed orally and can serve as an excellent probe molecule for understanding the biological function of PRMT5 in normal and cancer cells.

How Often Do You Lengthen? A Physician Survey on Lengthening Practice for Prosthetic Rib Devices.

STUDY DESIGN: Physician survey. OBJECTIVES: To identify physician practice patterns in use of prosthetic rib devices. BACKGROUND: Management of scoliosis with prosthetic ribs involves repeated expansions. Despite this, there is a paucity of literature on expansion practice. We believe that despite minimal literature, there exist surgeon practice patterns. METHODS: Thirty-seven surgeons from the Children's Spine Study Group, with prosthetic rib experience, were anonymously surveyed about their expansion practice. RESULTS: There was strong consensus that elapsed time since previous surgery was the most important factor in choosing lengthening intervals, with 94.5% of responders agreeing. Surgeons indicated that they often apply a standard expansion interval. 97.3% reported using one in >25% of cases, with 70.3% using a standard interval in >80% of cases. Six months was the most commonly reported elapsed time interval, with 78.4% of responders in agreement. There was also consensus on non-time factors. Patient maturity was cited a major factor in choosing lengthening interval in >80% of cases by 59.5% of responders. Patient age was frequently cited as a factor, with 73% of surgeons using it in >25% of cases. Additionally, there was consensus on factors that were not utilized. More than three-fourths (75.7%) stated that they use patients' bone quality <25% of the time. Similarly, 70.3% used resistance encountered in the last lengthening <25% of the time, with 13.5% never considering. CONCLUSION: Despite the lack of evidence-based guidelines regarding lengthening practice for prosthetic ribs, there is some consensus on the factors used to choose an appropriate expansion interval. The greatest consensus surrounded the use of a standard six-month elapsed time interval between expansions. From these data, we conclude that specialists have reached relative consensus on factors important for choosing an appropriate expansion interval. We believe these data are an important step toward developing best practice guidelines and identifying areas of equipoise amenable for future research. LEVEL OF EVIDENCE: Level V.

Quantitative dynamic MRI (QdMRI) Volumetric Analysis of Pediatric Patients with Thoracic Insufficiency Syndrome.

The lack of standardizable objective diagnostic measurement techniques is a major hurdle in the assessment and treatment of pediatric patients with thoracic insufficiency syndrome (TIS). The aim of this paper is to explore quantitative dynamic MRI (QdMRI) volumetric parameters derived from thoracic dMRI in pediatric patients with TIS and the relationships between dMRI parameters and clinical measurements. 25 TIS patients treated with vertical expandable prosthetic titanium rib (VEPTR) surgery are included in this retrospective study. Left and right lungs at end-inspiration and end-expiration are segmented from constructed 4D dMRI images. Lung volumes and excursion (or tidal) volumes of the left/right chest wall and hemi-diaphragms are computed. Commonly used clinical parameters include thoracic and lumbar Cobb angles and respiratory measurements from pulmonary function testing (PFT). 200 3D lungs in total (left & right, pre-operative & post-operative, end-inspiration & end-expiration) are segmented for analysis. Our analysis indicates that change of resting breathing rate (RR) following surgery is negatively correlated with that of QdMRI parameters. Chest wall tidal volumes and hemi-diaphragm tidal volumes increase significantly following surgery. Clinical parameter RR reduced after surgical treatment with P values around 0.06 but no significant differences were found on other clinical parameters. The significant increase in post-operative tidal volumes suggests a treatment-related improvement in lung capacity. The reduction of RR following surgery shows that breathing function is improved. The QdMRI parameters may offer an objective marker set for studying TIS, which is currently lacking.

Citrullination/Methylation Crosstalk on Histone H3 Regulates ER-Target Gene Transcription.

Posttranslational modifications of histone tails are a key contributor to epigenetic regulation. Histone H3 Arg26 and Lys27 are both modified by multiple enzymes, and their modifications have profound effects on gene expression. Citrullination of H3R26 by PAD2 and methylation of H3K27 by PRC2 have opposing downstream impacts on gene regulation; H3R26 citrullination activates gene expression, and H3K27 methylation represses gene expression. Both of these modifications are drivers of a variety of cancers, and their writer enzymes, PAD2 and EZH2, are the targets of drug therapies. After biochemical and cell-based analysis of these modifications, a negative crosstalk interaction is observed. Methylation of H3K27 slows citrullination of H3R26 30-fold, whereas citrullination of H3R26 slows methylation 30,000-fold. Examination of the mechanism of this crosstalk interaction uncovered a change in structure of the histone tail upon citrullination which prevents methylation by the PRC2 complex. This mechanism of crosstalk is reiterated in cell lines using knockdowns and inhibitors of both enzymes. Based our data, we propose a model in which, after H3 Cit26 formation, H3K27 demethylases are recruited to the chromatin to activate transcription. In total, our studies support the existence of crosstalk between citrullination of H3R26 and methylation of H3K27.

Management and outcomes of scoliosis in children with congenital diaphragmatic hernia.

PURPOSE: The purpose of this study was to evaluate the management and outcomes of CDH patients with scoliosis. METHODS: From January 1996 to August 2015, 26 of 380 (7%) CDH patients were diagnosed with scoliosis. Six (23%) were prenatally diagnosed by ultrasound, and 9 (35%) were diagnosed postnatally. The remaining 11 (42%) developed scoliosis after discharge. Mean follow-up was 6.6years. RESULTS: Among the 15 patients with congenital scoliosis, there were 2 (13%) perinatal deaths. Five of the 13 (38%) survivors required orthopedic surgery, and 2 have required bracing. The mean age at initial surgery was 7years. These five children underwent an average of 2.8 (range 1-7) expansions or revisions. All surgical patients required supplemental oxygen at 28days of life, and 1 required a tracheostomy. None of the 11 patients who developed scoliosis later in life required surgery, but 3 have required bracing. Six of the 11 (55%) required a patch repair for CDH compared to 158 of 264 (60%) CDH patients without scoliosis (p=0.73). CONCLUSIONS: Early diagnosis of scoliosis in CDH patients is associated with a high rate of surgery. There was not a higher incidence of patch repair among patients who developed scoliosis. LEVEL OF EVIDENCE: Prognosis. Retrospective study, level II.

NSD2 contributes to oncogenic RAS-driven transcription in lung cancer cells through long-range epigenetic activation.

The histone methyltransferase NSD2/WHSC1/MMSET is overexpressed in a number of solid tumors but its contribution to the biology of these tumors is not well understood. Here, we describe that NSD2 contributes to the proliferation of a subset of lung cancer cell lines by supporting oncogenic RAS transcriptional responses. NSD2 knock down combined with MEK or BRD4 inhibitors causes co-operative inhibitory responses on cell growth. However, while MEK and BRD4 inhibitors converge in the downregulation of genes associated with cancer-acquired super-enhancers, NSD2 inhibition affects the expression of clusters of genes embedded in megabase-scale regions marked with H3K36me2 and that contribute to the RAS transcription program. Thus, combinatorial therapies using MEK or BRD4 inhibitors together with NSD2 inhibition are likely to be needed to ensure a more comprehensive inhibition of oncogenic RAS-driven transcription programs in lung cancers with NSD2 overexpression.

Effect of Release of the First Pediatric Appropriate Use Criteria on Transthoracic Echocardiogram Ordering Practice.

Pediatric appropriate use criteria (AUC) were recently published for initial outpatient transthoracic echocardiography (TTE). The purpose of this study was to determine the effect of AUC publication on TTE ordering patterns of pediatric cardiologists. Data were prospectively collected on patients who had initial outpatient TTE ordered before (phase I, April to September 2014) and 3 months after (phase II, January to April 2015) AUC document publication at 6 centers. Site investigators assessed each study's indication and assigned AUC appropriateness as "appropriate" (A), "may be appropriate" (M), "rarely appropriate" (R), or "unclassifiable." One hundred three physicians ordered 4,562 TTEs (2,655 phase I and 1,907 phase II). Overall, there was no statistically significant change in the proportion of A, M, or unclassifiable, but R decreased (12.0% to 9.6%, p = 0.01). There was significant variability among the centers in the percentage of studies for indications rated R (4.9% to 34.8%). There was no significant change in any of the appropriateness ratings at 4 centers, a decrease in R and an increase in A at 1 and a decrease in R and increase in unclassifiable at another. The first pediatric AUC document had only a small impact on physician ordering behavior for initial TTEs, including a small decrease in R. There was a significant variability in appropriateness of studies among centers. These data suggest that active educational interventions are required to substantially improve the appropriate use of pediatric TTE in the outpatient setting.