RNA m6A reader YTHDF2 facilitates precursor miR-126 maturation to promote acute myeloid leukemia progression.

As the most common internal modification of mRNA, N6-methyladenosine (m6A) and its regulators modulate gene expression and play critical roles in various biological and pathological processes including tumorigenesis. It was reported previously that m6A methyltransferase (writer), methyltransferase-like 3 (METTL3) adds m6A in primary microRNAs (pri-miRNAs) and facilitates its processing into precursor miRNAs (pre-miRNAs). However, it is unknown whether m6A modification also plays a role in the maturation process of pre-miRNAs and (if so) whether such a function contributes to tumorigenesis. Here, we found that YTHDF2 is aberrantly overexpressed in acute myeloid leukemia (AML) patients, especially in relapsed patients, and plays an oncogenic role in AML. Moreover, YTHDF2 promotes expression of miR-126-3p (also known as miR-126, as it is the main product of precursor miR-126 (pre-miR-126)), a miRNA that was reported as an oncomiRNA in AML, through facilitating the processing of pre-miR-126 into mature miR-126. Mechanistically, YTHDF2 recognizes m6A modification in pre-miR-126 and recruits AGO2, a regulator of pre-miRNA processing, to promote the maturation of pre-miR-126. YTHDF2 positively and negatively correlates with miR-126 and miR-126's downstream target genes, respectively, in AML patients, and forced expression of miR-126 could largely rescue YTHDF2/Ythdf2 depletion-mediated suppression on AML cell growth/proliferation and leukemogenesis, indicating that miR-126 is a functionally important target of YTHDF2 in AML. Overall, our studies not only reveal a previously unappreciated YTHDF2/miR-126 axis in AML and highlight the therapeutic potential of targeting this axis for AML treatment, but also suggest that m6A plays a role in pre-miRNA processing that contributes to tumorigenesis.

QKI shuttles internal m7G-modified transcripts into stress granules and modulates mRNA metabolism.

N7-methylguanosine (m7G) modification, routinely occurring at mRNA 5' cap or within tRNAs/rRNAs, also exists internally in messenger RNAs (mRNAs). Although m7G-cap is essential for pre-mRNA processing and protein synthesis, the exact role of mRNA internal m7G modification remains elusive. Here, we report that mRNA internal m7G is selectively recognized by Quaking proteins (QKIs). By transcriptome-wide profiling/mapping of internal m7G methylome and QKI-binding sites, we identified more than 1,000 high-confidence m7G-modified and QKI-bound mRNA targets with a conserved "GANGAN (N = A/C/U/G)" motif. Strikingly, QKI7 interacts (via C terminus) with the stress granule (SG) core protein G3BP1 and shuttles internal m7G-modified transcripts into SGs to regulate mRNA stability and translation under stress conditions. Specifically, QKI7 attenuates the translation efficiency of essential genes in Hippo signaling pathways to sensitize cancer cells to chemotherapy. Collectively, we characterized QKIs as mRNA internal m7G-binding proteins that modulate target mRNA metabolism and cellular drug resistance.

Phosphorylation stabilized TET1 acts as an oncoprotein and therapeutic target in B cell acute lymphoblastic leukemia.

Although the overall survival rate of B cell acute lymphoblastic leukemia (B-ALL) in childhood is more than 80%, it is merely 30% in refractory/relapsed and adult patients with B-ALL. This demonstrates a need for improved therapy targeting this subgroup of B-ALL. Here, we show that the ten-eleven translocation 1 (TET1) protein, a dioxygenase involved in DNA demethylation, is overexpressed and plays a crucial oncogenic role independent of its catalytic activity in B-ALL. Consistent with its oncogenic role in B-ALL, overexpression of TET1 alone in normal precursor B cells is sufficient to transform the cells and cause B-ALL in mice within 3 to 4 months. We found that TET1 protein is stabilized and overexpressed because of its phosphorylation mediated by protein kinase C epsilon (PRKCE) and ATM serine/threonine kinase (ATM), which are also overexpressed in B-ALL. Mechanistically, TET1 recruits STAT5B to the promoters of CD72 and JCHAIN and promotes their transcription, which in turn promotes B-ALL development. Destabilization of TET1 protein by treatment with PKC or ATM inhibitors (staurosporine or AZD0156; both tested in clinical trials), or by pharmacological targeting of STAT5B, greatly decreases B-ALL cell viability and inhibits B-ALL progression in vitro and in vivo. The combination of AZD0156 with staurosporine or vincristine exhibits a synergistic effect on inhibition of refractory/relapsed B-ALL cell survival and leukemia progression in PDX models. Collectively, our study reveals an oncogenic role of the phosphorylated TET1 protein in B-ALL independent of its catalytic activity and highlights the therapeutic potential of targeting TET1 signaling for the treatment of refractory/relapsed B-ALL.

METTL16 drives leukemogenesis and leukemia stem cell self-renewal by reprogramming BCAA metabolism.

N6-methyladenosine (m6A), the most prevalent internal modification in mammalian mRNAs, is involved in many pathological processes. METTL16 is a recently identified m6A methyltransferase. However, its role in leukemia has yet to be investigated. Here, we show that METTL16 is a highly essential gene for the survival of acute myeloid leukemia (AML) cells via CRISPR-Cas9 screening and experimental validation. METTL16 is aberrantly overexpressed in human AML cells, especially in leukemia stem cells (LSCs) and leukemia-initiating cells (LICs). Genetic depletion of METTL16 dramatically suppresses AML initiation/development and maintenance and significantly attenuates LSC/LIC self-renewal, while moderately influencing normal hematopoiesis in mice. Mechanistically, METTL16 exerts its oncogenic role by promoting expression of branched-chain amino acid (BCAA) transaminase 1 (BCAT1) and BCAT2 in an m6A-dependent manner and reprogramming BCAA metabolism in AML. Collectively, our results characterize the METTL16/m6A/BCAT1-2/BCAA axis in leukemogenesis and highlight the essential role of METTL16-mediated m6A epitranscriptome and BCAA metabolism reprograming in leukemogenesis and LSC/LIC maintenance.

RNA N6 -methyladenosine reader YTHDC1 is essential for TGF-beta-mediated metastasis of triple negative breast cancer.

RNA N6 -methyladenosine (m6A) modification and its regulators fine tune gene expression and contribute to tumorigenesis. This study aims to uncover the essential role and the underlying molecular mechanism(s) of the m6A reader YTHDC1 in promoting triple negative breast cancer (TNBC) metastasis. METHODS: In vitro and in vivo models were employed to determine the pathological function of YTHDC1 in TNBC metastasis. To identify bona fide YTHDC1 target RNAs, we conducted RNA-seq, m6A-seq, and RIP-seq, followed by integrative data analysis and validation assays. RESULTS: By analyzing The Cancer Genome Atlas (TCGA) dataset, we found that elevated expression of YTHDC1 is positively correlated with poor prognosis in breast cancer patients. Using a mammary fat pad mouse model of TNBC, YTHDC1 significantly promoted lung metastasis of TNBC cells. Through multiple transcriptome-wide sequencing and integrative data analysis, we revealed dysregulation of metastasis-related pathways following YTHDC1 depletion and identified SMAD3 as a bona fide YTHDC1 target RNA. Depletion of YTHDC1 caused nuclear retention of SMAD3 mRNA, leading to lower SMAD3 protein levels. Loss of YTHDC1 led to impaired TGF-ß-induced gene expression, leading to inhibition of epithelial-mesenchymal transition (EMT) and suppressed TNBC cell migration and invasion. SMAD3 overexpression was able to restore the response to TGF-ß in YTHDC1 depleted TNBC cells. Furthermore, we demonstrated that the oncogenic role of YTHDC1 is mediated through its recognition of m6A as m6A-binding defective mutants of YTHDC1 were unable to rescue the impaired cell migration and invasion of YTHDC1 knockout TNBC cells. CONCLUSIONS: We show that YTHDC1 plays a critical oncogenic role in TNBC metastasis through promoting the nuclear export and expression of SMAD3 to augment the TGF-ß signaling cascade. Overall, our study demonstrates that YTHDC1 is vital for TNBC progression by enhancing TNBC cell survival and TGF-ß-mediated EMT via SMAD3 to enable the formation of distant metastasis and highlights the therapeutic potential of targeting the YTHDC1/m6A/SMAD3 axis for TNBC treatment.

In the hands of a few: Disaster recovery committee networks.

When disaster strikes, urban planners often rely on feedback and guidance from committees of officials, residents, and interest groups when crafting reconstruction policy. Focusing on recovery planning committees after Japan's 2011 earthquake, tsunami, and nuclear disasters, we compile and analyze a dataset on committee membership patterns across 39 committees with 657 members. Using descriptive statistics and social network analysis, we examine 1) how community representation through membership varied among committees, and 2) in what ways did committees share members, interlinking members from certain interests groups. This study finds that community representation varies considerably among committees, negatively related to the prevalence of experts, bureaucrats, and business interests. Committee membership overlap occurred heavily along geographic boundaries, bridged by engineers and government officials. Engineers and government bureaucrats also tend to be connected to more members of the committee network than community representatives, giving them prized positions to disseminate ideas about best practices in recovery. This study underscores the importance of diversity and community representation in disaster recovery planning to facilitate equal participation, information access, and policy implementation across communities.

Left Ventricular Global Strain Analysis by Two-Dimensional Speckle-Tracking Echocardiography: The Learning Curve.

BACKGROUND: The application of left ventricular (LV) global strain by speckle-tracking is becoming more widespread, with the potential for incorporation into routine clinical echocardiography in selected patients. There are no guidelines or recommendations for the training requirements to achieve competency. The aim of this study was to determine the learning curve for global strain analysis and determine the number of studies that are required for independent reporting. METHODS: Three groups of novice observers (cardiology fellows, cardiac sonographers, medical students) received the same standardized training module prior to undertaking retrospective global strain analysis on 100 patients over a period of 3 months. To assess the effect of learning, quartiles of 25 patients were read successively by each blinded observer, and the results were compared to expert for correlation. RESULTS: Global longitudinal strain (GLS) had uniform learning curves and was the easiest to learn, requiring a minimum of 50 patients to achieve expert competency (intraclass correlation coefficient > 0.9) in all three groups over a period of 3 months. Prior background knowledge in echocardiography is an influential factor affecting the learning for interobserver reproducibility and time efficiency. Short-axis strain analysis using global circumferential stain and global radial strain did not yield a comprehensive learning curve, and expert level was not achieved by the end of the study. CONCLUSIONS: There is a significant learning curve associated with LV strain analysis. We recommend a minimum of 50 studies for training to achieve competency in GLS analysis.

A rare mechanism of very late bare metal stent thrombosis--role of optical coherence imaging in its evaluation and management.

Very late stent thrombosis is an uncommon event following implantation with bare metal stents (BMS) in coronary arteries. Long term follow up studies have shown that a small number of BMS develop very late thrombosis following years of stability. Atherosclerotic transformation of neointimal tissue is increasingly being recognised as the cause of these adverse events. A 49 year-old male presented with acute inferior wall myocardial infarction resulting from thrombosis of the BMS implanted in his right coronary artery five years earlier. He was successfully thrombolysed and his coronary angiogram showed mild diffuse instent restenosis. The intravascular optical coherence tomography revealed instent neoatherosclerotic plaque rupture without any flow limiting stenosis as the likely culprit event.

Drug eluting stents trapping intramural hematoma in spontaneous coronary artery dissection and healing pattern at six months: optical coherence tomography findings.

Spontaneous coronary artery dissections (SCAD) are often difficult to diagnose and manage. Intravascular imaging such as optical coherence tomography (OCT) improves diagnosis and may assist in management. Recent data suggest that percutaneous coronary interventions (PCI) in in SCAD are associated with poor outcomes. This report provides striking OCT images of potential complications associated with PCI in SCAD, as well as demonstrates medium term OCT data in residual hematoma healing and stent coverage in SCAD.

Day procedure intervention is safe and complication free in higher risk patients undergoing transradial angioplasty and stenting. The discharge study.

OBJECTIVES: To assess the timeframe of postprocedural complications following transradial percutaneous intervention in selected nonlow-risk risk patients as a feasibility study for same day discharge. BACKGROUND: Percutaneous coronary intervention (PCI) is traditionally performed as an inpatient procedure. Transradial access with its lower complication rate facilitates safe and same day discharge. We hypothesize that with current standards of pharmacotherapy and intervention, complications post transradial percutaneous coronary angioplasty even in a nonlow-risk patient cohort will be evident within 6 hr or occur more than 24 hr post procedure. Under these circumstances, overnight stay results in no improvement in patient safety. METHODS: 2,189 patients underwent transradial PCI at our institution between January 2005 and June 2006. Of these 1,174 were assessed as intermediate or high risk and admitted postprocedure. The remaining 1,015 were assessed as low risk and discharged the day of procedure. All 1,174 inpatients were entered into our study database. Information was collected on patient demographics, angiographic characteristics, post procedural complications, and timing of post procedural events. RESULTS: 1,543 ACC type B2 or C lesions were treated in 1,174 patients. All post-procedural complications were identified within 6 hr of the intervention or occurred more than 24 hr later when patients would have been discharged according to overnight admission protocols. CONCLUSIONS: Day case transradial percutaneous intervention with a 6-hr period of post procedure observation is a safe and feasible practice. The presence of higher-risk features should not be considered an absolute indication for overnight admission in patients considered clinically appropriate for discharge.

Suspected aortic dissection and other aortic disorders: multi-detector row CT in 373 cases in the emergency setting.

PURPOSE: To retrospectively review the authors' experience with multi-detector row computed tomography (CT) for detection of aortic dissection in the emergency setting. MATERIALS AND METHODS: The investigation was institutional review board approved, did not require informed patient consent, and was HIPAA compliant. In 373 clinical evaluations in the emergency setting, 365 patients suspected of having aortic dissection and/or other aortic disorders underwent multidetector CT. Criteria for acute aortic disorder were confirmed by using surgical and pathologic diagnoses or findings at clinical follow-up and any subsequent imaging as the reference standard. Positive cases were characterized according to type of disorder interpreted. Resulting sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated by using two-way contingency tables. All cases found to be negative for acute aortic disorders were grouped according to alternative CT findings. RESULTS: Sixty-seven (18.0%) of the 373 cases were interpreted as positive for acute aortic disorder. One hundred twelve acute aortic disorders were identified in these 67 cases: 23 acute aortic dissections, 14 acute aortic intramural hematomas, 20 acute penetrating aortic ulcers, 44 new or enlarging aortic aneurysms, and 11 acute aortic ruptures. Three hundred five (81.8%) cases were interpreted as negative for acute aortic disorder. In 48 negative cases, multidetector CT depicted alternative findings that accounted for the clinical presentation. Of these, three included both acute aortic disorders and alternative findings, and 45 included only alternative findings. One (0.3%) case was indeterminate for acute aortic disorder. Overall, 112 findings were interpreted as positive for acute aortic disorder, an alternative finding, or both at CT. No interpretations were false-positive, one was false-negative, 67 were true-positive, and 304 were true-negative. Sensitivity, specificity, PPV, NPV, and accuracy were 99% (67 of 68), 100% (304 of 304), 100% (67 of 67), 99.7% (304 of 305), and 99.5% (371 of 373), respectively. CONCLUSION: The positivity rate for acute aortic dissection or other acute aortic disorder in 373 cases examined at multi-detector row CT was 18.0%.

Trends in the use of CT and radiography in the evaluation of facial trauma, 1992-2002: implications for current costs.

OBJECTIVE: CT has replaced conventional radiography of the face in many trauma centers. Concern exists that increased costs are associated with increased use of CT. Our goal was to compare the amount of CT and radiography performed for facial trauma at a level 1 trauma center in 1992 and in 2002 and to determine hospital costs for the imaging of these patients. MATERIALS AND METHODS: The changes in volume and types of facial imaging examinations were determined comparing 1992 and 2002. Hospital costs of different imaging examinations were determined for 2002. Current costs of imaging facial trauma were compared with what 2002 costs would have been if the practice pattern in 1992 had continued. RESULTS: In 1992, 890 patients were evaluated for facial trauma. Six hundred seventy-one had only radiography, 153 only CT of the face, and 66 both CT and radiography. In 2002, 828 patients were evaluated. Five hundred eighty-four patients had only CT of the face; 228, only radiography; and 16, both CT and radiography. The number of facial imaging examinations per patient in 1992 and 2002 was 1.23 and 1.03, respectively. The 2002 hospital cost of a facial CT examination was $121 and of a facial radiography series was $154. Using CT instead of radiography for evaluating facial injury resulted in an overall cost savings of 22% per patient in 2002. CONCLUSION: The availability of CT has not resulted in increased use of facial imaging. The increased use of CT from 1992 to 2002 results in decreased current costs for the hospital.