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Cancer Biology Commons

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Full-Text Articles in Cancer Biology

Functional Characterization Of Cancer-Associated Dna Polymerase Ε Variants, Stephanie R. Barbari Dec 2021

Functional Characterization Of Cancer-Associated Dna Polymerase Ε Variants, Stephanie R. Barbari

Theses & Dissertations

Replicative DNA polymerases ε (Polε) and δ (Polδ) achieve high fidelity DNA synthesis through a precise balance of polymerization and exonucleolytic proofreading. Errors that escape proofreading are corrected by DNA mismatch repair (MMR). Ultramutated human cancers with proficient MMR carry alterations in the exonuclease domain of Polε, which were initially predicted to abolish proofreading. However, functional studies in yeast of the most recurrent Polε-P286R variant suggested defects beyond a loss of exonuclease activity. Indeed, biochemical analysis of the yeast Polε-P286R analog revealed increased polymerization capacity in addition to decreased proofreading, which enables efficient mismatch extension and bypass of replication-blocking non-B …


The Role Of Histone Chaperone Fact Complex In Base Excision Repair Pathway And Its Therapeutic Potential In Colon Cancer And Medulloblastoma, Heyu Song Dec 2019

The Role Of Histone Chaperone Fact Complex In Base Excision Repair Pathway And Its Therapeutic Potential In Colon Cancer And Medulloblastoma, Heyu Song

Theses & Dissertations

Base excision repair (BER) pathway is required for the removal of damaged bases caused by alkylation, oxidation and ring-saturation. Human apurinic/apyrimidinic endonuclease 1 (APE1) plays a central role in BER pathway. Although repair of damaged bases by recombinant APE1 has been well investigated in vitro, how APE1 gains access to damaged bases in the context of chromatin is largely unknown. A prominent member of the histone chaperone family, FACT (Facilitates Chromatin Transcription) is thought to reorganize nucleosomes through the destabilization of multiple intra-nucleosome contacts. FACT complex is composed of two polypeptides identified as SPT16 (Suppressor of Ty 16) and SSRP1 …


Defining The Role Of Interferon Regulatory Factor 4 In Chronic Lymphocytic Leukemia., Vipul Shukla May 2016

Defining The Role Of Interferon Regulatory Factor 4 In Chronic Lymphocytic Leukemia., Vipul Shukla

Theses & Dissertations

Chronic Lymphocytic Leukemia (CLL) represents the most common adult leukemia in the Western hemisphere. Despite considerable progress in our current understanding of CLL, this disease remains incurable and the molecular events underlying the complex pathogenesis of CLL are not fully elucidated. Interferon Regulatory Factor 4 (IRF4) belongs to the IRF superfamily of transcription factors that has been shown to play critical roles at multiple stages of B cell development. Interestingly, a Genome Wide Association Study identified Single Nucleotide Polymorphism (SNP) mediated IRF4 down regulation, as a major predisposing genetic event during the development of CLL. However, whether low levels of …


Recurrent Mutations Of T-Cell Receptor And Co-Stimulatory Signaling Proteins In Peripheral T-Cell Lymphomas, Joseph Rohr May 2016

Recurrent Mutations Of T-Cell Receptor And Co-Stimulatory Signaling Proteins In Peripheral T-Cell Lymphomas, Joseph Rohr

Theses & Dissertations

Peripheral T-cell lymphomas (PTCLs) comprise a heterogeneous group of mature T-cell neoplasms with a poor prognosis. Recently, mutations in TET2 and other epigenetic modifiers as well as RHOA have been identified in these diseases, particularly in angioimmunoblastic T-cell lymphoma (AITL). CD28 is the major co-stimulatory receptor in T-cells which, upon binding ligand, induces sustained T-cell proliferation and cytokine production when combined with T-cell receptor stimulation, through many signaling molecules including VAV1. This thesis identifies recurrent mutations in CD28 in PTCLs, as well as mutations in VAV1. Two residues of CD28 – D124 and T195 – were recurrently mutated in 11.3% …