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University of Tennessee Health Science Center

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Full-Text Articles in Medical Molecular Biology

Identifying The Molecular Cause Of Extreme Endoplasmic Reticulum Dilation In Pediatric Osteosarcoma And Its Relationship To The Disease, Rachael Wood Dec 2021

Identifying The Molecular Cause Of Extreme Endoplasmic Reticulum Dilation In Pediatric Osteosarcoma And Its Relationship To The Disease, Rachael Wood

Theses and Dissertations (ETD)

Pediatric osteosarcoma tumors are characterized by an unusual abundance of grossly dilated endoplasmic reticulum and an immense genomic instability that has complicated identifying new effective molecular therapeutic targets. Here we report a novel molecular signature that encompasses the majority of 108 patient tumor samples, PDXs and osteosarcoma cell lines. These tumors exhibit reduced expression of four critical COPII vesicle proteins that has resulted in the accumulation of procollagen-I protein within ‘hallmark’ dilated ER. Using CRISPR activation technology, increased expression of only SAR1A and SEC24D to physiologically normal levels was sufficient to restore both collagen-I secretion and resolve dilated ER morphology …


The Heme-Regulated Inhibitor Pathway Modulates Susceptibility Of Poor Prognosis B-Lineage Acute Leukemia To Bh3-Mimetics, Kaitlyn Hill Smith Apr 2021

The Heme-Regulated Inhibitor Pathway Modulates Susceptibility Of Poor Prognosis B-Lineage Acute Leukemia To Bh3-Mimetics, Kaitlyn Hill Smith

Theses and Dissertations (ETD)

Anti-apoptotic MCL1 is one of the most frequently amplified genes in human cancers and its elevated expression confers resistance to many therapeutics including the BH3-mimetic agents ABT-199 and ABT-263. The anti-malarial, dihydroartemisinin (DHA) translationally represses MCL-1 and synergizes with BH3-mimetics. To explore how DHA represses MCL-1, a genome-wide CRISPR screen identified that loss of genes in the heme synthesis pathway renders mouse BCR-ABL+ B-ALL cells resistant to DHA-induced death. Mechanistically, DHA disrupts the interaction between heme and the eIF2α kinase heme regulated inhibitor (HRI) triggering the integrated stress response. Genetic ablation of Eif2ak1, which encodes HRI, blocks MCL-1 repression in …