Publications by authors named "Nikki Kong"

Student-faculty partnerships can drive innovation in parasitology education and outreach. We provide recommendations for building successful partnerships during the design, implementation, and impact assessment stages. We also introduce a new series of freely available educational and community outreach materials available on a platform that the parasitology community can contribute to.

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Targeted protein degradation (TPD) has emerged as a potentially transformational therapeutic modality with considerable promise. Molecular glue degraders remodel the surface of E3 ligases inducing interactions with neosubstrates resulting in their polyubiquitination and proteasomal degradation. Molecular glues are clinically precedented and have demonstrated the ability to degrade proteins-of-interest (POIs) previously deemed undruggable due to the absence of a traditional small molecule binding pocket.

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Thalidomide and its derivatives are molecular glues that bind cereblon (CRBN), a component of an E3 ubiquitin ligase complex, and mediate protein interactions with neosubstrates resulting in their polyubiquitination and proteasomal degradation. The structural features of neosubstrate binding have been elucidated that highlight key interactions with a β-hairpin degron containing a glycine, which is present in a wide-range of proteins, including zinc-finger transcription factors such as IKZF1, and the translation termination factor GSPT1. Here, we profile 14 closely-related thalidomide derivatives in CRBN occupancy, and IKZF1 and GSPT1 degradation cell-based assays, and use crystal structures, computational docking and molecular dynamics to delineate subtle structure-activity relationships.

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Article Synopsis
  • - The study focuses on creating new covalent inhibitor drugs by targeting histidine residues in proteins, as traditional methods often rely on targeting cysteine, which is less common in binding sites.
  • - The researchers utilized structure-based drug design to develop the compound EM12, which effectively interacts with a specific histidine (His353) in the cereblon E3 ubiquitin ligase complex, leading to potent inhibition.
  • - Additionally, the compound EM12-FS, while able to label His353, also disrupts a related protein essential for certain cellular processes, showcasing the potential for targeted protein degradation in drug discovery.
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Immunomodulatory drugs (IMiDs) thalidomide, lenalidomide, and pomalidomide engage cereblon and mediate a protein interface with neosubstrates such as zinc finger transcription factors promoting their polyubiquitination and degradation. The IMiDs have garnered considerable excitement in drug discovery, leading to exploration of targeted protein degradation strategies. Although the molecular modes-of-action of the IMiDs and related degraders have been the subject of intense research, their pharmacokinetics and disposition have been relatively understudied.

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Article Synopsis
  • Oncofetal protein SALL4 is important for the survival of cancer cells, but targeting it only works for patients with SALL4-positive tumors.
  • Researchers discovered that by artificially introducing SALL4 in SALL4-negative cancer cells, these cells became partially reliant on SALL4 for survival, which could be exploited for treatment.
  • Using the FDA-approved drug 5-aza-2'-deoxycytidine (DAC) to induce SALL4 expression in these cancer cells made them more sensitive to another drug, entinostat, allowing for a new therapeutic strategy for previously untreatable patients.
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CUT&RUN is a recently developed chromatin profiling technique that enables high-resolution chromatin mapping and probing. Herein, we describe our adapted CUT&RUN protocol for transcription factors (TFs). Our protocol outlines all necessary steps for TF profiling including the procedure to obtain proteinA-Mnase, while also outlining the bioinformatic pipeline steps required to process, analyze, and identify novel binding sites and sequences.

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The architecture of chromatin regulates eukaryotic cell states by controlling transcription factor access to sites of gene regulation. Here we describe a dual transposase-peroxidase approach, integrative DNA and protein tagging (iDAPT), which detects both DNA (iDAPT-seq) and protein (iDAPT-MS) associated with accessible regions of chromatin. In addition to direct identification of bound transcription factors, iDAPT enables the inference of their gene regulatory networks, protein interactors and regulation of chromatin accessibility.

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The zinc finger transcription factor SALL4 is highly expressed in embryonic stem cells, downregulated in most adult tissues, but reactivated in many aggressive cancers. This unique expression pattern makes SALL4 an attractive therapeutic target. However, whether SALL4 binds DNA directly to regulate gene expression is unclear, and many of its targets in cancer cells remain elusive.

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Background & Aims: Some oncogenes encode transcription factors, but few drugs have been successfully developed to block their activity specifically in cancer cells. The transcription factor SALL4 is aberrantly expressed in solid tumor and leukemia cells. We developed a screen to identify compounds that reduce the viability of liver cancer cells that express high levels of SALL4, and we investigated their mechanisms.

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Hematopoietic stem cells are capable of self-renewal or differentiation along three main lineages: myeloid, erythroid, and lymphoid. One of the earliest lineage decisions for blood progenitor cells is whether to adopt the lymphoid or myeloid fate. Previous work had shown that myocyte enhancer factor 2C (MEF2C) is indispensable for the lymphoid fate decision, yet the specific mechanism of action remained unclear.

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There is a growing body of evidence supporting that cancer cells share many similarities with embryonic stem cells (ESCs). For example, aggressive cancers and ESCs share a common gene expression signature that includes hundreds of genes. Since ESC genes are not present in most adult tissues, they could be ideal candidate targets for cancer-specific diagnosis and treatment.

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Amphibian neural development occurs as a two-step process: (1) induction specifies a neural fate in undifferentiated ectoderm; and (2) transformation induces posterior spinal cord and hindbrain. Signaling through the Fgf, retinoic acid (RA) and Wnt/β-catenin pathways is necessary and sufficient to induce posterior fates in the neural plate, yet a mechanistic understanding of the process is lacking. Here, we screened for factors enriched in posterior neural tissue and identify spalt-like 4 (sall4), which is induced by Fgf.

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The embryonic stem (ES) cell gene has recently been identified as a new target for cancer therapy, including leukemia. SALL4 is expressed in ES cells and during embryonic development, but is absent in most adult tissues. It is, however, aberrantly expressed in various solid tumors and hematologic malignancies such as myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML).

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Background: Stem cell factor SALL4 is a zinc finger transcription factor. It plays vital roles in the maintenance of embryonic stem cell properties, functions as an oncogene in leukemia, and has been recently proposed to use for cord blood expansion. The mechanism(s) by which SALL4 functions in normal human hematopoiesis, including identification of its target genes, still need to be explored.

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Transcriptional repressors are thought to inhibit gene expression by interfering with the binding or function of RNA Polymerase II, perhaps by promoting local chromatin condensation. Here, we present evidence for a distinctive mechanism of repression, whereby sequence-specific repressors prevent the looping of distal enhancers to the promoter. Particular efforts focus on the Snail repressor, which plays a conserved role in promoting epithelial-mesenchyme transitions in both invertebrates and vertebrates, including mesoderm invagination in Drosophila, neural crest migration in vertebrates, and tumorigenesis in mammals.

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SALL4, a member of the SALL gene family, is one of the most important transcriptional regulators of stem cells. It is of particular interest to stem cell biologists because it is linked to the self-renewal of both embryonic stem cells (ESCs) and hematopoietic stem cells (HSCs), and it is involved in human leukemia. In ESCs, the Sall4/Oct4/Nanog core transcriptional network governs the self-renewal and pluripotent properties of human and murine ESCs.

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Background: The embryonic stem cell (ESC) factor, SALL4, plays an essential role in both development and leukemogenesis. It is a unique gene that is involved in self-renewal in ESC and leukemic stem cell (LSC).

Methodology/principal Findings: To understand the mechanism(s) of SALL4 function(s), we sought to identify SALL4-associated proteins by tandem mass spectrometry.

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SALL4, a newly identified zinc-finger transcriptional factor important for embryonic development, is mapped to chromosome 20q13. Previously, we reported that SALL4 was constitutively expressed in acute myeloid leukemia and SALL4 transgenic mice developed acute myeloid leukemia. In this study, we aimed to survey SALL4 protein expression in benign and neoplastic hematopoietic tissues in addition to acute myeloid leukemia using immunostaining with a polyclonal anti-SALL4 antibody.

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