Chromatin organization in myelodysplastic syndrome.

Disordered chromatin organization has emerged as a new aspect of the pathogenesis of myelodysplastic syndrome (MDS). Characterized by lineage dysplasia and a high transformation rate to acute myeloid leukemia (AML), the genetic determinant of MDS is thought to be the main driver of the disease's progression. Among the recurrently mutated pathways, alterations in chromatin organization, such as the cohesin complex, have a profound impact on hematopoietic stem cell (HSC) function and lineage commitment. The cohesin complex is a ring-like structure comprised of structural maintenance of chromosomes (SMC), RAD21, and STAG proteins that involve three-dimensional (3D) genome organization via loop extrusion in mammalian cells. The partial loss of the functional cohesin ring leads to altered chromatin accessibility specific to key hematopoietic transcription factors, which is thought to be the molecular mechanism of cohesin dysfunction. Currently, there are no specific targeting agents for cohesin mutant MDS/AML. Potential therapeutic strategies have been proposed based on the current understanding of cohesin mutant leukemogenesis. Here, we will review the recent advances in investigation and targeting approaches against cohesin mutant MDS/AML.

Noncanonical Activity of Med4 as a Gatekeeper of Metastasis through Epigenetic Control of Integrin Signaling.

Breast cancer metastatic relapse after a latency period, known as metastatic dormancy. Through genetic screening in mice, we identified the mediator complex subunit 4 (Med4) as a novel tumor-cell intrinsic gatekeeper in metastatic reactivation. Med4 downregulation effectively awakened dormant breast cancer cells, prompting macroscopic metastatic outgrowth in the lungs. Med4 depletion results in profound changes in nuclear size and three-dimensional chromatin architecture from compacted to relaxed states in contrast to the canonical function of the Mediator complex. These changes rewire the expression of extracellular matrix proteins, integrins, and signaling components resulting in integrin-mediated mechano-transduction and activation of YAP and MRTF. The assembly of stress fibers pulls on the nuclear membrane and contributes to reinforcing the overall chromatin modifications by Med4 depletion. MED4 gene deletions were observed in patients with metastatic breast cancer, and reduced MED4 expression correlates with worse prognosis, highlighting its significance as a potential biomarker for recurrence.

Dysregulated miRNAs modulate tumor microenvironment associated signaling networks in pancreatic ductal adenocarcinoma.

The desmoplastic and complex tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) has presented tremendous challenges for developing effective therapeutic strategies. Strategies targeting tumor stroma, albeit with great potential, have met with limited success due to the lack of knowledge on the molecular dynamics within the tumor microenvironment (TME). In pursuit of a better understanding of the influence of miRNAs on TME reprogramming and to explore circulating miRNAs as diagnostic and prognostic biomarkers for PDAC, using RNA-seq, miRNA-seq, and single-cell RNA-seq (scRNA-seq), we investigated the dysregulated signaling pathways in PDAC TME modulated by miRNAs from plasma and tumor tissue. Our bulk RNA-seq in PDAC tumor tissue identified 1445 significantly differentially expressed genes with extracellular matrix and structure organization as the top enriched pathways. Our miRNA-seq identified 322 and 49 abnormally expressed miRNAs in PDAC patient plasma and tumor tissue, respectively. We found many of the TME signaling pathways were targeted by those dysregulated miRNAs in PDAC plasma. Combined with scRNA-seq from patient PDAC tumor, our results revealed that these dysregulated miRNAs were closely associated with extracellular matrix (ECM) remodeling, cell-ECM communication, epithelial-mesenchymal transition, as well as immunosuppression orchestrated by different cellular components of TME. The findings of this study could assist the development of miRNA-based stromal targeting biomarkers or therapy for PDAC patients.

Till SMARCA5 loss do nucleosomes part.

In this issue of Molecular Cell, Bomber et al. demonstrate that acute loss of SMARCA5 in human cells leads to eviction of CTCF and an increase in nucleosome repeat length without direct impact on transcriptional activity.

National trends and clinical outcomes of interventional approaches following admission for infected necrotizing pancreatitis in the United States.

BACKGROUND: With recent studies demonstrating the efficacy of minimally invasive approaches following infected necrotizing pancreatitis, latest guideline recommendations support their use. However, large-scale studies are lacking, and the national landscape following these guidelines remains poorly characterized. The present study examined trends in intervention strategies and the association of approach on clinical outcomes and resource use in a nationally representative cohort. METHODS: The 2016-2019 National Inpatient Sample was queried for adult hospitalizations for pancreatitis with infected necrosis. Patients were classified as drain only (DO) if they received only percutaneous or endoscopic drainage, minimally invasive (MIS) if they underwent endoscopic or laparoscopic debridement, and Open if they underwent open debridement. The primary outcome was in-hospital mortality, while secondary outcomes included perioperative complications, home discharge, and resource use. Multivariable regression models were developed to evaluate the association of intervention with clinical and financial endpoints. RESULTS: Of 4,605 patients who received interventions, 1,735 (37.6%) were DO, 1,490 (32.4%) were MIS, and 1,380 (30.0%) were considered Open. The proportion of DO and MIS increased, while Open declined (2016, 47.0%; 2019, 24.6%; p < 0.001). Compared with Open, MIS had lower rates of abdominal compartment syndrome while having greater rates of preoperative closed drainage (31.9% vs. 13.8%, p < 0.001). After adjustment, odds of in-hospital mortality, respiratory failure, prolonged ventilation, and acute kidney injury were significantly higher in the Open cohort compared with MIS. Hospitalization duration was longer ( ß , +12.1 days; 95% confidence interval, 6.8-17.5), and costs were higher ( ß , +$58.7K; 95% confidence interval, 33.5-83.9) in Open compared with MIS. CONCLUSION: Minimally invasive approaches for infected pancreatic necrosis have increased over time, while open necrosectomy has declined. Open approaches compared with drainage only or minimally invasive debridement were associated with greater odds of numerous in-hospital complications and resource burden. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Srsf2P95H/+ co-operates with loss of TET2 to promote myeloid bias and initiate a chronic myelomonocytic leukemia-like disease in mice.

Recurrent mutations in RNA splicing proteins and epigenetic regulators contribute to the development of myelodysplastic syndrome (MDS) and related myeloid neoplasms. In chronic myelomonocytic leukemia (CMML), SRSF2 mutations occur in ~50% of patients and TET2 mutations in ~60%. Clonal analysis indicates that either mutation can arise as the founder lesion. Based on human cancer genetics we crossed an inducible Srsf2P95H/+ mutant model with Tet2fl/fl mice to mutate both concomitantly in hematopoietic stem cells. At 20-24 weeks post mutation induction, we observed subtle differences in the Srsf2/Tet2 mutants compared to either single mutant. Under conditions of native hematopoiesis with aging, we see a distinct myeloid bias and monocytosis in the Srsf2/Tet2 mutants. A subset of the compound Srsf2/Tet2 mutants display an increased granulocytic and distinctive monocytic proliferation (myelomonocytic hyperplasia), with increased immature promonocytes and monoblasts and binucleate promonocytes. Exome analysis of progressed disease demonstrated mutations in genes and pathways similar to those reported in human CMML. Upon transplantation, recipients developed leukocytosis, monocytosis, and splenomegaly. We reproduce Srsf2/Tet2 co-operativity in vivo, yielding a disease with core characteristics of CMML, unlike single Srsf2 or Tet2 mutation. This model represents a significant step toward building high fidelity and genetically tractable models of CMML.

Genome-wide screening identifies cell-cycle control as a synthetic lethal pathway with SRSF2P95H mutation.

Current strategies to target RNA splicing mutant myeloid cancers proposes targeting the remaining splicing apparatus. This approach has only been modestly sensitizing and is also toxic to non-mutant-bearing wild-type cells. To explore potentially exploitable genetic interactions with spliceosome mutations, we combined data mining and functional screening for synthetic lethal interactions with an Srsf2P95H/+ mutation. Analysis of missplicing events in a series of both human and murine SRSF2P95H mutant samples across multiple myeloid diseases (acute myeloid leukemia, myelodysplastic syndromes, chronic myelomonocytic leukemia) was performed to identify conserved missplicing events. From this analysis, we identified that the cell-cycle and DNA repair pathways were overrepresented within the conserved misspliced transcript sets. In parallel, to functionally define pathways essential for survival and proliferation of Srsf2P95H/+ cells, we performed a genome-wide Clustered regularly interspaced short palindromic repeat loss-of-function screen using Hoxb8 immortalized R26-CreERki/+Srsf2P95H/+ and R26-CreERki/+Srsf2+/+ cell lines. We assessed loss of single guide RNA representation at 3 timepoints: immediately after Srsf2P95H/+ activation, and at 1 week and 2 weeks after Srsf2P95H/+ mutation. Pathway analysis demonstrated that the cell-cycle and DNA damage response pathways were among the top synthetic lethal pathways with Srsf2P95H/+ mutation. Based on the loss of guide RNAs targeting Cdk6, we identified that palbociclib, a CDK6 inhibitor, showed preferential sensitivity in Srsf2P95H/+ cell lines and in primary nonimmortalized lin-cKIT+Sca-1+ cells compared with wild-type controls. Our data strongly suggest that the cell-cycle and DNA damage response pathways are required for Srsf2P95H/+ cell survival, and that palbociclib could be an alternative therapeutic option for targeting SRSF2 mutant cancers.

Sarcopenia Is Associated with Mortality in Adults: A Systematic Review and Meta-Analysis.

BACKGROUND: Sarcopenia can predispose individuals to falls, fractures, hospitalization, and mortality. The prevalence of sarcopenia depends on the population studied and the definition used for the diagnosis. OBJECTIVE: This systematic review and meta-analysis aimed to investigate the association between sarcopenia and mortality and if it is dependent on the population and sarcopenia definition. METHODS: A systematic search was conducted in MEDLINE, EMBASE, and Cochrane from 1 January 2010 to 6 April 2020 for articles relating to sarcopenia and mortality. Articles were included if they met the following criteria - cohorts with a mean or median age ≥18 years and either of the following sarcopenia definitions: Asian Working Group for Sarcopenia (AWGS and AWGS2019), European Working Group on Sarcopenia in Older People (EWGSOP and EWGSOP2), Foundation for the National Institutes of Health (FNIH), International Working Group for Sarcopenia (IWGS), or Sarcopenia Definition and Outcomes Consortium (SDOC). Hazard ratios (HR) and odds ratios (OR) were pooled separately in meta-analyses using a random-effects model, stratified by population (community-dwelling adults, outpatients, inpatients, and nursing home residents). Subgroup analyses were performed for sarcopenia definition and follow-up period. RESULTS: Out of 3,025 articles, 57 articles were included in the systematic review and 56 in the meta-analysis (42,108 participants, mean age of 49.4 ± 11.7 to 86.6 ± 1.0 years, 40.3% females). Overall, sarcopenia was associated with a significantly higher risk of mortality (HR: 2.00 [95% CI: 1.71, 2.34]; OR: 2.35 [95% CI: 1.64, 3.37]), which was independent of population, sarcopenia definition, and follow-up period in subgroup analyses. CONCLUSIONS: Sarcopenia is associated with a significantly higher risk of mortality, independent of population and sarcopenia definition, which highlights the need for screening and early diagnosis in all populations.

Selective Estrogen Receptor Modulators: A Potential Option For Non-Binary Gender-Affirming Hormonal Care?

Gender dysphoria describes the distress associated with having a gender identity that differs from one's birth-assigned sex. To relieve this distress, transgender, and gender diverse (henceforth, trans) individuals commonly undergo medical transition involving hormonal treatments. Current hormonal treatment guidelines cater almost exclusively for those who wish to transition from male to female or vice versa. In contrast, there is a dearth of hormonal options for those trans individuals who identify as non-binary and seek an androgynous appearance that is neither overtly male nor female. Though prolonged puberty suppression with gonadotrophin releasing hormone agonists (GnRHa) could in theory be gender-affirming by preventing the development of unwanted secondary sex characteristics, this treatment option would be limited to pre- or peri-pubertal adolescents and likely have harmful effects. Here, we discuss the theoretical use of Selective Estrogen Receptor Modulators (SERMs) for non-binary people assigned male at birth (AMAB) who are seeking an androgynous appearance through partial feminization without breast growth. Given their unique range of pharmacodynamic effects, SERMs may represent a potential gender-affirming treatment for this population, but there is a lack of knowledge regarding their use and potentially adverse effects in this context.

Sarcopenia is associated with 3-month and 1-year mortality in geriatric rehabilitation inpatients: RESORT.

BACKGROUND: Sarcopenia is highly prevalent in geriatric rehabilitation patients and can worsen prognosis. This study aimed to investigate the association of sarcopenia and components of sarcopenia with 3-month and 1-year post-discharge mortality in geriatric rehabilitation inpatients. METHODS: REStORing health of acutely unwell adulTs (RESORT) is an observational, prospective longitudinal cohort of geriatric rehabilitation inpatients. Sex-stratified Cox proportional-hazards analyses were used to associate sarcopenia (and its components) at admission, by the European Working Group on Sarcopenia in Older People (EWGSOP, EWGSOP2) and the Asian Working Group for Sarcopenia 2019 (AWGS 2019), with 3-month and 1-year post-discharge all-cause mortality. RESULTS: Patients (n = 1,406) had a median interquartile ranges [IQR] age of 83.0 [77.4-88.2] years (58% females). Sarcopenia was significantly associated with 3-month and 1-year mortality in females (EWGSOP, EWGSOP2 and AWGS 2019) and males (EWGSOP2, AWGS 2019). In females, low muscle mass (EWGSOP, EWGSOP2 and AWGS 2019) was significantly associated with 3-month and 1-year mortality; low muscle strength (EWGSOP, EWGSOP2 and AWGS 2019) was significantly associated with 1-year mortality. For males, low muscle mass (EWGSOP2, AWGS 2019) was significantly associated with 3-month and 1-year mortality; low muscle strength (EWGSOP2, AWGS 2019) was significantly associated with 3-month mortality. The association between physical performance with mortality was not analysed due to less than five events (death) in patients with normal physical performance. CONCLUSIONS: Sarcopenia, low muscle mass and low muscle strength at admission are associated with a significantly higher risk of mortality post-discharge from geriatric rehabilitation, highlighting the need to measure muscle mass and strength in clinical practice.

Learning arbitrary stimulus-reward associations for naturalistic stimuli involves transition from learning about features to learning about objects.

Most cognitive processes are studied using abstract or synthetic stimuli with specific features to fully control what is presented to subjects. However, recent studies have revealed enhancements of cognitive capacities (such as working memory) when processing naturalistic versus abstract stimuli. Using abstract stimuli constructed from distinct visual features (e.g., color and shape), we have recently shown that human subjects can learn multidimensional stimulus-reward associations via initially estimating reward value of individual features (feature-based learning) before gradually switching to learning about reward value of individual stimuli (object-based learning). Here, we examined whether similar strategies are adopted during learning about naturalistic stimuli that are clearly perceived as objects (instead of a combination of features) and contain both task-relevant and irrelevant features. We found that similar to learning about abstract stimuli, subjects initially adopted feature-based learning more strongly before transitioning to object-based learning. However, there were three key differences between learning about naturalistic and abstract stimuli. First, compared with abstract stimuli, the initial learning strategy was less feature-based for naturalistic stimuli. Second, subjects transitioned to object-based learning faster for naturalistic stimuli. Third, unexpectedly, subjects were more likely to adopt feature-based learning for naturalistic stimuli, both at the steady state and overall. These results suggest that despite the stronger tendency to perceive naturalistic stimuli as objects, which leads to greater likelihood of using object-based learning as the initial strategy and a faster transition to object-based learning, the influence of individual features on learning is stronger for these stimuli such that ultimately the object-based strategy is adopted less. Overall, our findings suggest that feature-based learning is a general initial strategy for learning about reward value of all types of multi-dimensional stimuli.

Switching to Lurasidone following 12 months of treatment with Risperidone: results of a 6-month, open-label study.

BACKGROUND: Patients with a diagnosis of schizophrenia are at an increased risk for developing metabolic syndrome, which is associated with greater cardiovascular morbidity and mortality. Treatment with some commonly used antipsychotic medications may increase the risk of developing metabolic syndrome. The aim of the study was to evaluate the safety of lurasidone in patients who continued lurasidone or switched from risperidone to lurasidone. A secondary aim was assessment of the effect of long-term lurasidone on the Positive and Negative Syndrome Scale (PANSS). METHODS: The treatment sample in the current study consisted of clinically stable patients with schizophrenia (N = 223) who had completed a 12-month, double-blind study of lurasidone vs. risperidone. In the current extension study, all patients received 6 months of open-label treatment with lurasidone, either continuing lurasidone assigned during the preceding double-blind trial, or switching from double-blind risperidone to lurasidone. Safety and tolerability parameters included body weight, prolactin, and metabolic laboratory tests. RESULTS: Six months of OL treatment with lurasidone was generally well-tolerated, with a low incidence of parkinsonism (4.5%) and akathisia (3.1%). Overall, few adverse events were rated as severe (4.9%), and discontinuation due to an adverse event was low in the lurasidone continuation vs. risperidone switch groups (3.7% vs. 6.9%). In the lurasidone continuation versus risperidone switch groups, change from OL baseline to 6-month endpoint (observed case) was observed in mean body weight (- 0.6 vs. -2.6 kg), median total cholesterol (- 4.0 vs. + 4.5 mg/dL), triglycerides (- 4.5 vs. -5.5 mg/dL), glucose (0.0 vs. -3.0 mg/dL) and prolactin (males, + 0.15 vs. -11.2 ng/mL; females, + 1.3 vs. -30.8 ng/mL). Improvement in PANSS total score was maintained, from OL baseline to endpoint in the continuation vs. switch groups (+ 1.0 vs. -1.0; OC). CONCLUSIONS: In this 6-month extension study, lurasidone treatment was generally well-tolerated and associated with minimal effects on weight, metabolic parameters, and prolactin levels. Patients who switched from risperidone to lurasidone experienced reductions in weight, metabolic parameters and prolactin levels commensurate with increases in these safety parameters experienced during the previous 12 months of treatment with risperidone. TRIAL REGISTRATION: ClinicalTrials.gov NCT00641745 (Date of Registration: March 24, 2008).

Gastric Cancer Peritoneal Carcinomatosis Risk Score.

BACKGROUND: Gastric cancer (GC) peritoneal carcinomatosis (PC) is associated with a poor prognosis. Although grade, histology, and stage are associated with PC, the cumulative risk of PC when multiple risk factors are present is unknown. This study aimed to develop a cumulative GCPC risk score based on individual demographic/tumor characteristics. METHODS: Patient-level data (2004-2014) from the California Cancer Registry were reviewed by creating a keyword search algorithm to identify patients with gastric PC. Multivariable logistic regression was used to assess demographic/tumor characteristics associated with PC in a randomly selected testing cohort. Scores were assigned to risk factors based on beta coefficients from the logistic regression result, and these scores were applied to the remainder of the subjects (validation cohort). The summed scores of each risk factor formed the total risk score. These were grouped, showing the percentages of patients with PC. RESULTS: The study identified 4285 patients with gastric adenocarcinoma (2757 males, 64.3%). The median age of the patients was 67 years (interquartile range [IQR], 20 years). Most of the patients were non-Hispanic white (n = 1748, 40.8%), with proximal (n = 1675, 39.1%) and poorly differentiated (n = 2908, 67.9%) tumors. The characteristics most highly associated with PC were T4 (odds ratio [OR], 3.12; 95% confidence interval [CI], 2.19-4.44), overlapping location (OR 2.27; 95% CI 1.52-3.39), age of 20-40 years (OR 3.42; 95% CI 2.24-5.21), and Hispanic ethnicity (OR 1.86; 95% CI 1.36-2.54). The demographic/tumor characteristics used in the risk score included age, race/ethnicity, T stage, histology, tumor grade, and location. Increasing GCPC score was associated with increasing percentage of patients with PC. CONCLUSION: Based on demographic/tumor characteristics in GC, it is possible to distinguish groups with varying odds for PC. Understanding the risk for PC based on the cumulative effect of high-risk features can help clinicians to customize surveillance strategies and can aid in early identification of PC.

Modeling human RNA spliceosome mutations in the mouse: not all mice were created equal.

Myelodysplastic syndromes (MDS) and related myelodysplastic/myeloproliferative neoplasms (MDS/MPNs) are clonal stem cell disorders, primarily affecting patients over 65 years of age. Mapping of the MDS and MDS/MPN genome identified recurrent heterozygous mutations in the RNA splicing machinery, with the SF3B1, SRSF2, and U2AF1 genes being frequently mutated. To better understand how spliceosomal mutations contribute to MDS pathogenesis in vivo, numerous groups have sought to establish conditional murine models of SF3B1, SRSF2, and U2AF1 mutations. The high degree of conservation of hematopoiesis between mice and human and the well-established phenotyping and genetic modification approaches make murine models an effective tool with which to study how a gene mutation contributes to disease pathogenesis. The murine models of spliceosomal mutations described to date recapitulate human MDS or MDS/MPN to varying extents. Reasons for the differences in phenotypes reported between alleles of the same mutation are varied, but the nature of the genetic modification itself and subsequent analysis methods are important to consider. In this review, we summarize recently reported murine models of SF3B1, SRSF2, and U2AF1 mutations, with a particular focus on the genetically engineered modifications underlying the models and the experimental approaches applied.

Srsf2P95H initiates myeloid bias and myelodysplastic/myeloproliferative syndrome from hemopoietic stem cells.

Mutations in SRSF2 occur in myelodysplastic syndromes (MDS) and MDS/myeloproliferative neoplasms (MPN). SRSF2 mutations cluster at proline 95, with the most frequent mutation being a histidine (P95H) substitution. They undergo positive selection, arise early in the course of disease, and have been identified in age-related clonal hemopoiesis. It is not clear how mutation of SRSF2 modifies hemopoiesis or contributes to the development of myeloid bias or MDS/MPN. Two prior mouse models of Srsf2P95H mutation have been reported; however, these models do not recapitulate many of the clinical features of SRSF2-mutant disease and relied on bone marrow (BM) transplantation stress to elicit the reported phenotypes. We describe a new conditional murine Srsf2P95H mutation model, where the P95H mutation is expressed physiologically and heterozygously from its endogenous locus after Cre activation. Using multiple Cre lines, we demonstrate that during native hemopoiesis (ie, no BM transplantation), the Srsf2P95H mutation needs to occur within the hemopoietic stem-cell-containing populations to promote myelomonocytic bias and expansion with corresponding transcriptional and RNA splicing changes. With age, nontransplanted Srsf2P95H animals developed a progressive, transplantable disease characterized by myeloid bias, morphological dysplasia, and monocytosis, hallmarks of MDS/MPN in humans. Analysis of cooccurring mutations within the BM demonstrated the acquisition of additional mutations that are recurrent in humans with SRSF2 mutations. The tractable Srsf2P95H/+ knock-in model we have generated is highly relevant to human disease and will serve to elucidate the effect of SRSF2 mutations on initiation and maintenance of MDS/MPN.

Five lessons in uncomplicated appendicitis: Can we remove the surgery?

Appendicectomy has remained the treatment of choice for appendicitis for over a century and is the most commonly performed emergency operation in children. However, emerging evidence suggests that appendicectomy may not always be necessary in uncomplicated appendicitis, with early paediatric trials demonstrating that antibiotic-only therapy can be safe and effective. Further rigorously designed and appropriately powered studies are necessarily to establish the place of non-operative management of uncomplicated appendicitis in the future.

Nonoperative management in children with early acute appendicitis: A systematic review.

PURPOSE: Appendectomy has remained the gold standard treatment of acute appendicitis for more than 100years. Nonoperative management (NOM) has been shown to be a valid treatment alternative for acute uncomplicated appendicitis in adults. A systematic review of available evidence comparing operative management (OM) and NOM in children with acute uncomplicated appendicitis was performed. METHODS: Systematic searches of MedLine, Embase, and a clinical trial register (https://clinicaltrials.gov/) were performed in March 2016. Only articles that studied NOM for uncomplicated appendicitis in children were included. Data generation was performed independently by two authors, and quality was assessed using the rating schema by the Oxford Centre for Evidence-Based Medicine. RESULTS: 15 articles were selected: four retrospective analyses, four prospective cohort studies, four prospective nonrandomized comparative trials and one randomized controlled trial (RCT). Initial success of the NOM groups (a cure within two weeks of intervention) ranged from 58 to 100%, with 0.1-31.8% recurrence at one year. CONCLUSION: Although present literature is scarce, publications support the feasibility of further studies investigating NOM of acute uncomplicated appendicitis in children. Higher quality prospective RCTs with larger sample sizes and robust randomization methods, studying the noninferiority of NOM with antibiotics compared with OM are required to establish its utility. LEVEL OF EVIDENCE: This manuscript is a systematic review and thus assigned the lowest evidence used from the manuscripts analyzed which is a Level IV.

Acute uncomplicated appendicitis study: rationale and protocol for a multicentre, prospective randomised controlled non-inferiority study to evaluate the safety and effectiveness of non-operative management in children with acute uncomplicated appendicitis.

INTRODUCTION: This article presents an overview of a prospective randomised controlled non-inferiority study designed to evaluate the safety and effectiveness of non-operative management (NOM) with operative management in children with acute uncomplicated appendicitis (AUA). Here, we present the study protocol for this APRES study, a multicentre Australian study. The rationale and details of future analysis, in particular, non-inferiority calculations, cost-effectiveness, feasibility and acceptability of each intervention. DESIGN: A multicentre, prospective randomised controlled clinical trial, conducted in 2 Australian tertiary paediatric hospitals. PARTICIPANTS: Children who meet the inclusion criteria of an age between 5 and 15 years and a clinical diagnosis of AUA will be invited to participate, and after consent will be randomised via a computer-based program into treatment groups. The study started in June 2016, and the target recruitment is 220 patients. INTERVENTIONS: Children in the control group will be treated with prophylactic antibiotics and appendicectomy, and those in the intervention group will be treated with antibiotic therapy alone. Primary outcome measures include unplanned or unnecessary operation and complications at 30 days. Secondary outcomes include longer term complications within 1 year, length of stay, time off work and school analgesic requirements and cost. ANALYSIS: Data analyses will be on the intention-to-treat principle using non-inferiority analysis. Analysis will include the Pearson χ2 test for categorical variables and independent sample t-test or Mann-Whitney test for continuous variables. Non-inferiority for NOM will be tested using 1-sided Wald tests with an α level of 0.05. ETHICS AND DISSEMINATION: The research has been approved by the Human Research Ethics Committee of the Sydney Children's Hospital Network. In addition, results will be reported through academic journals, seminars and conference presentations. TRIAL REGISTRATION NUMBERS: NCT02795793; ACTRN12616000788471.

Enhanced Antitumor Activity of an Anti-5T4 Antibody-Drug Conjugate in Combination with PI3K/mTOR inhibitors or Taxanes.

PURPOSE: Targeted treatment of solid or liquid tumors with antibody-drug conjugates (ADCs) can lead to promising clinical benefit. The aim of the study is to investigate combination regimens of auristatin-based ADCs in preclinical models of cancer. EXPERIMENTAL DESIGN: An auristatin-based anti-5T4 antibody conjugate (5T4-ADC) and auristatin payloads were combined with the dual PI3K/mTOR catalytic site inhibitor PF-05212384 (PF-384) or taxanes in a panel of tumor cell lines. Drug interactions in vitro were evaluated using cell viability assays, apoptosis induction, immunofluorescence, mitotic index, and immunoblotting. Breast cancer cells treated with auristatin analogue or 5T4-ADC were profiled by total- and phospho-proteomics. Antitumor efficacy of selected combinations was evaluated in 5T4-positive human breast or lung tumor xenografts in vivo. RESULTS: In vitro, auristatin-based agents displayed strong synergistic or additive activity when combined with PF-384 or taxanes, respectively. Further, treatment of 5T4-ADC plus PF-384 resulted in stronger induction of apoptosis and cell line-specific attenuation of pAKT and pGSK. Interestingly, proteomic analysis revealed unique effects of auristatins on multiple components of mRNA translation. Addition of PF-384 further amplified effects of 5T4-ADC on translational components, providing a potential mechanism of synergy between these drugs. In human tumor xenografts, dual targeting with 5T4-ADC/PF-384 or 5T4-ADC/paclitaxel produced substantially greater antitumor effects with longer average survival as compared with monotherapy treatments. CONCLUSIONS: Our results provide a biologic rationale for combining 5T4-ADC with either PI3K/mTOR pathway inhibitors or taxanes and suggest that mechanisms underlying the synergy may be attributed to cellular effects of the auristatin payload.