Publications by authors named "Jeffrey Chang"

tRNA modifications are critical for several aspects of their functions, including decoding, folding, and stability. Using a multifaceted approach encompassing eCLIP-seq and nanopore tRNA-seq, we show that the human tRNA methyltransferase TRMT1L interacts with the component of the Rix1 ribosome biogenesis complex and binds to the 28S rRNA as well as to a subset of tRNAs. Mechanistically, we demonstrate that TRMT1L is responsible for catalyzing N2,N2-dimethylguanosine (mG) solely at position 27 of tRNA-Tyr-GUA.

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Metaplastic breast cancer (MpBC) is a highly chemoresistant subtype of breast cancer with no standardized therapy options. A clinical study in anthracycline-refractory MpBC patients suggested that nitric oxide synthase (NOS) inhibitor NG-monomethyl-l-arginine (L-NMMA) may augment anti-tumor efficacy of taxane. We report that NOS blockade potentiated response of human MpBC cell lines and tumors to phosphoinositide 3-kinase (PI3K) inhibitor alpelisib and taxane.

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Triple negative breast cancer (TNBC) that fails to respond to neoadjuvant chemotherapy (NACT) can be lethal. Developing effective strategies to eradicate chemoresistant disease requires experimental models that recapitulate the heterogeneity characteristic of TNBC. To that end, we established a biobank of 92 orthotopic patient-derived xenograft (PDX) models of TNBC from the tumors of 75 patients enrolled in the ARTEMIS clinical trial ( NCT02276443 ) at MD Anderson Cancer Center, including 12 longitudinal sets generated from serial patient biopsies collected throughout NACT and from metastatic disease.

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Research Question: Could a predictive model, using data from all US fertility clinics reporting to the Society for Assisted Reproductive Technology, estimate the likelihood of patients using their stored oocytes?

Design: Multiple learner algorithms, including penalized regressions, random forests, gradient boosting machine, linear discriminant analysis and bootstrap aggregating decision trees were used. Data were split into training and test datasets. Patient demographics, medical and fertility diagnoses, partner information and geographic locations were analysed.

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To retrospectively analyze clinical outcomes of patients with "treatment-resistant" neovascular age-related macular degeneration or diabetic macular edema who were switched to intravitreal faricimab injections (IFIs) using a "real-world" treat-and-extend (TAE) protocol. Seventy-one eyes from 62 patients receiving antivascular endothelial growth factor injections were evaluated before and after switching to IFI. Demographic and clinical data were collected.

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tRNA modifications are critical for several aspects of their functions, including decoding, folding, and stability. Using a multifaceted approach encompassing eCLIP-seq and Nanopore tRNA-seq, we show that the human tRNA methyltransferase TRMT1L interacts with component of the Rix1 ribosome biogenesis complex and binds to the 28S rRNA, as well as to a subset of tRNAs. Mechanistically, we demonstrate that TRMT1L is responsible for catalyzing m G solely at position 27 of tRNA-Tyr-GUA.

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Article Synopsis
  • The study investigates the effectiveness of the anti-EGFR monoclonal antibody panitumumab combined with carboplatin and paclitaxel for treating chemotherapy-resistant triple-negative breast cancer (TNBC) patients.
  • It included 43 patients who had not sufficiently responded to prior doxorubicin and cyclophosphamide treatment, achieving a combined pathological complete response/residual cancer burden class I rate of 30.2%.
  • The results indicate that panitumumab shows promise as part of neoadjuvant therapy for TNBC, warranting further evaluation in larger clinical trials.
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Luminal androgen receptor (LAR)-enriched triple-negative breast cancer (TNBC) is a distinct subtype. The efficacy of AR inhibitors and the relevant biomarkers in neoadjuvant therapy (NAT) are yet to be determined. We tested the combination of the AR inhibitor enzalutamide (120 mg daily by mouth) and paclitaxel (80 mg/m weekly intravenously) (ZT) for 12 weeks as NAT for LAR-enriched TNBC.

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Triple negative breast cancer (TNBC) accounts for 15-20% of breast cancer cases in the United States. Systemic neoadjuvant chemotherapy (NACT), with or without immunotherapy, is the current standard of care for patients with early-stage TNBC. However, up to 70% of TNBC patients have significant residual disease once NACT is completed, which is associated with a high risk of developing recurrence within two to three years of surgical resection.

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Background: Cancer susceptibility germline mutations are associated with pancreatic ductal adenocarcinoma (PDAC). However, the hereditary status of PDAC and its impact on survival is largely unknown in the Asian population.

Methods: Exome sequencing was performed on 527 blood samples from PDAC individuals and analyzed for mutations in 80 oncogenic genes.

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Objectives: The aim of this research was to compare the penetration ability of calcium silicate-based sealers (iRoot SP and TotalFill BC HiFlow) and an epoxy resin-based sealer (AH Plus) into the lateral canals using the single-cone (SC) or continuous wave compaction (CW) obturation techniques.

Methods: Ninety single-rooted human teeth received canal instrumentation and diaphanisation before artificial lateral canals were created at 3 different root levels. The specimens were randomly allocated into 6 groups based on the combination of obturation technique and sealer used.

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Tumors are comprised of subpopulations of cancer cells that harbor distinct genetic profiles and phenotypes that evolve over time and during treatment. By reconstructing the course of cancer evolution, we can understand the acquisition of the malignant properties that drive tumor progression. Unfortunately, recovering the evolutionary relationships of individual cancer cells linked to their phenotypes remains a difficult challenge.

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Article Synopsis
  • Recent research focuses on the phosphoinositide 3-kinase pathway in breast cancer, highlighting the role of PTEN as a crucial component.
  • The study aimed to investigate PTEN expression changes in triple-negative breast cancer (TNBC) patients and assess if next-generation sequencing (NGS) could effectively identify PTEN loss, serving as an alternative to traditional immunohistochemistry (IHC).
  • Findings revealed inconsistencies in PTEN expression between pretreatment and post-treatment samples, with some tumors showing intratumoral heterogeneity and overlapping copy numbers, suggesting that testing multiple specimens may be necessary for accurate assessment in clinical trials.
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Chromophore photoisomerization is a fundamental process in chemistry and in the activation of many photosensitive proteins. A major task is understanding the effect of the protein environment on the efficiency and direction of this reaction compared to what is observed in the gas and solution phases. In this study, we set out to visualize the hula twist (HT) mechanism in a fluorescent protein, which is hypothesized to be the preferred mechanism in a spatially constrained binding pocket.

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Publications comparing variant caller algorithms present discordant results with contradictory rankings. Caller performances are inconsistent and wide ranging, and dependent upon input data, application, parameter settings, and evaluation metric. With no single variant caller emerging as a superior standard, combinations or ensembles of variant callers have appeared in the literature.

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Aim: This in vitro study aimed to evaluate the effect of matrix metalloproteinase (MMP) inhibitors on the bond strength of resin-cemented fibre posts to radicular dentin under an aged-loaded condition.

Materials And Methods: Radicular dentin was prepared and irrigated by MMP inhibitor solution after root canal obturation in 60 extracted single-rooted teeth based on 6 groups: (1) 2% chlorhexidine (CHX) + loaded; (2) CHX + unloaded; (3) 0.5% benzalkonium chloride (BAC) + loaded; (4) BAC + unloaded; (5) 17% ethylenediaminetetraacetic acid (EDTA) + loaded; and (6) EDTA + unloaded.

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Background: Postpartum hemorrhage (PPH) is one of the leading causes of obstetric complications. The goal of this study was to identify risk factors for obstetric (OB) massive transfusion (MT) and determine the feasibility of developing a low-titer group O RhD-positive whole blood (LTO + WB) protocol for OB hemorrhage.

Study Design And Methods: A retrospective study of OB patients who received transfusion within 24 h.

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High-grade serous ovarian cancer (HGSC) is frequently characterized by homologous recombination (HR) DNA repair deficiency and, while most such tumors are sensitive to initial treatment, acquired resistance is common. We undertook a multiomics approach to interrogate molecular diversity in end-stage disease, using multiple autopsy samples collected from 15 women with HR-deficient HGSC. Patients had polyclonal disease, and several resistance mechanisms were identified within most patients, including reversion mutations and HR restoration by other means.

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The Omicron BA.1 variant of SARS-CoV-2 escapes convalescent sera and monoclonal antibodies that are effective against earlier strains of the virus. This immune evasion is largely a consequence of mutations in the BA.

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Objective: To test the hypothesis that the (i) presence of non-carious cervical lesions (NCCLs) and (ii) type of post system have no effect on the fracture resistance and pattern in endodontically treated maxillary premolars.

Methods: Human maxillary first premolars (n=60) with two root canals were randomly allocated into four groups (n=15). Buccal wedge-shaped NCCLs were prepared in 45 teeth specimens.

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For many classes of biomolecules, population-level heterogeneity is an essential aspect of biological function─from antibodies produced by the immune system to post-translationally modified proteins that regulate cellular processes. However, heterogeneity is difficult to fully characterize for multiple reasons: (i) single-molecule approaches are needed to avoid information lost by ensemble-level averaging, (ii) sufficient statistics must be gathered on both a per-molecule and per-population level, and (iii) a suitable analysis framework is required to make sense of a potentially limited number of intrinsically noisy measurements. Here, we introduce an approach that overcomes these difficulties by combining three techniques: a DNA nanoswitch construct to repeatedly interrogate the same molecule, a benchtop centrifuge force microscope (CFM) to obtain thousands of statistics in a highly parallel manner, and a Bayesian nonparametric (BNP) inference method to resolve separate subpopulations with distinct kinetics.

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Oncogenic KRAS expression generates a metabolic dependency on aerobic glycolysis, known as the Warburg effect. We report an effect of increased glycolytic flux that feeds into glycosphingolipid biosynthesis and is directly linked to KRAS oncogenic function. High resolution imaging and genetic approaches show that a defined subset of outer leaflet glycosphingolipids, including GM3 and SM4, is required to maintain KRAS plasma membrane localization, with GM3 engaging in cross-bilayer coupling to maintain inner leaflet phosphatidylserine content.

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Article Synopsis
  • Patient-derived xenograft (PDX) models of breast cancer offer a powerful method for drug testing and discovering biomarkers, especially in triple-negative breast cancer (TNBC).
  • The research involved creating PDX models from breast cancer patients before and after neoadjuvant chemotherapy, resulting in 62 successful models from a total of 269 samples, with better success rates from treatment-resistant tumors.
  • A predictive model for PDX engraftment was established, focusing on key patient tumor characteristics, and these PDX models are now a valuable resource for advancing treatment strategies in TNBC.
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