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Browsing by Author "Qin, Zhaohui"
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Item Combined loss of Tet1 and Tet2 promotes B-cell, but not myeloid malignancies in mice.(Elsevier, 2015-11-24) Zhao, Zhigang; Chen, Li; Dawlaty, Meelad M.; Pan, Feng; Weeks, Ophelia; Zhou, Yuan; Cao, Zeng; Shi, Hui; Wang, Jiapeng; Lin, Li; Chen, Shi; Yuan, Weiping; Qin, Zhaohui; Ni, Hongyu; Nimer, Stephen D.; Yang, Feng-Chun; Jaenisch, Rudolf; Jin, Peng; Xu, Mingjiang; Department of Pediatrics, IU School of MedicineTET1/2/3 are methylcytosine dioxygenases that regulate cytosine hydroxymethylation. Tet1/2 are abundantly expressed in HSC/HPCs and are implicated in hematological malignancies. Tet2-deletion in mice causes myeloid malignancies, while Tet1-null mice develop B-cell lymphoma after an extended period of latency. Interestingly, TET1/2 are often concomitantly downregulated in acute B-lymphocytic leukemia. Here, we investigated the overlapping and non-redundant functions of Tet1/2 in HSC maintenance and development of hematological malignancies using Tet1/2 double knockout (DKO) mice. DKO and Tet2−/− HSC/HPCs showed overlapping and unique 5hmC and 5mC profiles, and behaved differently. DKO mice exhibited strikingly decreased incidence and delayed-onset of myeloid malignancies compared to Tet2−/− mice, and in contrast developed lethal B-cell malignancies. Transcriptome analysis of DKO tumors revealed expression changes in many genes dysregulated in human B-cell malignancies, such as LMO2, BCL6 and MYC. These results highlight the critical roles of TET1/2 individually and together via communication in the pathogenesis of hematological malignancies.Item MammOnc-DB, an integrative breast cancer data analysis platform for target discovery(Research Square, 2024-09-26) Varambally, Sooryanarayana; Karthikeyan, Santhosh Kumar; Chandrashekar, Darshan; Sahai, Snigdha; Shrestha, Sadeep; Aneja, Ritu; Singh, Rajesh; Kleer, Celina; Kumar, Sidharth; Qin, Zhaohui; Nakshatri, Harikrishna; Manne, Upender; Creighton , Chad; Surgery, School of MedicineBreast cancer (BCa) is one of the most common malignancies among women worldwide. It is a complex disease that is characterized by morphological and molecular heterogeneity. In the early stages of the disease, most BCa cases are treatable, particularly hormone receptor-positive and HER2-positive tumors. Unfortunately, triple-negative BCa and metastases to distant organs are largely untreatable with current medical interventions. Recent advances in sequencing and proteomic technologies have improved our understanding of the molecular changes that occur during breast cancer initiation and progression. In this era of precision medicine, researchers and clinicians aim to identify subclass-specific BCa biomarkers and develop new targets and drugs to guide treatment. Although vast amounts of omics data including single cell sequencing data, can be accessed through public repositories, there is a lack of user-friendly platforms that integrate information from multiple studies. Thus, to meet the need for a simple yet effective and integrative BCa tool for multi-omics data analysis and visualization, we developed a comprehensive BCa data analysis platform called MammOnc-DB (http://resource.path.uab.edu/MammOnc-Home.html), comprising data from more than 20,000 BCa samples. MammOnc-DB was developed to provide a unique resource for hypothesis generation and testing, as well as for the discovery of biomarkers and therapeutic targets. The platform also provides pre- and post-treatment data, which can help users identify treatment resistance markers and patient groups that may benefit from combination therapy.Item Targeting MLL1 H3K4 methyltransferase activity in mixed-lineage leukemia(Elsevier, 2014-01-23) Cao, Fang; Townsend, Elizabeth C.; Karatas, Hacer; Xu, Jing; Li, Li; Lee, Shirley; Liu, Liu; Chen, Yong; Ouillette, Peter; Zhu, Jidong; Hess, Jay L.; Atadja, Peter; Lei, Ming; Qin, Zhaohui; Malek, Sami; Wang, Shaomeng; Dou, Yali; IU School of MedicineHere we report a comprehensive characterization of our recently developed inhibitor MM-401 that targets the MLL1 H3K4 methyltransferase activity. MM-401 is able to specifically inhibit MLL1 activity by blocking MLL1-WDR5 interaction and thus the complex assembly. This targeting strategy does not affect other mixed-lineage leukemia (MLL) family histone methyltransferases (HMTs), revealing a unique regulatory feature for the MLL1 complex. Using MM-401 and its enantiomer control MM-NC-401, we show that inhibiting MLL1 methyltransferase activity specifically blocks proliferation of MLL cells by inducing cell-cycle arrest, apoptosis, and myeloid differentiation without general toxicity to normal bone marrow cells or non-MLL cells. More importantly, transcriptome analyses show that MM-401 induces changes in gene expression similar to those of MLL1 deletion, supporting a predominant role of MLL1 activity in regulating MLL1-dependent leukemia transcription program. We envision broad applications for MM-401 in basic and translational research.