Publications by authors named "Andrew C Porter"

This article examined the discriminant and convergent validity of commonly used self-report measures of self-criticism, self-esteem, and shame. A confirmatory factor analysis (CFA) using multiple self-report measures of each construct showed low levels of discriminant validity between self-reported self-esteem, shame, and self-criticism and instead demonstrated correspondingly high levels of shared variance. However, bifactor analyses on the items across each measure suggested that self-report measures of self-esteem, shame, and self-criticism may contain distinct characteristics that are underrepresented in current measures of each construct.

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This paper examined the unique associations of latent self-esteem with symptoms of depression, over-and-above latent shame-proneness (study 1) and latent self-criticism (study 2), among two samples of undergraduate students. In study 1, confirmatory factor analysis (CFA) showed convergent and discriminant validity for most measures of shame-proneness and self-esteem. Shame-proneness and self-esteem (taken separately) were strongly related to depressive symptoms.

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The current review provides an evidence base update of psychosocial treatments for self-injurious thoughts and behaviors (SITBs) in youth. A systematic search was conducted of 2 major scientific databases (PsycInfo and PubMed) and ClinicalTrials.gov for relevant randomized controlled trials (RCTs) published prior to June 2018.

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This study examined the unique associations of shame-proneness and self-criticism to symptoms of disordered eating and depression among 186 undergraduate students. The study also tested the degree to which self-criticism and shame-proneness accounted for the association between disordered eating and depressive symptoms. Both shame-proneness and self-criticism were significantly related to disordered eating and depressive symptoms.

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We demonstrate the usefulness of synthetic lethal screening of a conditionally BCL6-deficient Burkitt lymphoma cell line, DG75-AB7, with a library of small molecules to determine survival pathways suppressed by BCL6 and suggest mechanism-based treatments for lymphoma. Lestaurtinib, a JAK2 inhibitor and one of the hits from the screen, repressed survival of BCL6-deficient cells in vitro and reduced growth and proliferation of xenografts in vivo BCL6 deficiency in DG75-AB7 induced JAK2 mRNA and protein expression and STAT3 phosphorylation. Surface IL10RA was elevated by BCL6 deficiency, and blockade of IL10RA repressed STAT3 phosphorylation.

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DNA double-strand breaks (DSBs) are toxic lesions, which if improperly repaired can result in cell death or genomic instability. DSB repair is usually facilitated by the classical non-homologous end joining (C-NHEJ), or homologous recombination (HR) pathways. However, a mutagenic alternative NHEJ pathway, microhomology-mediated end joining (MMEJ), can also be deployed.

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Understanding the mechanisms of chromosomal double-strand break repair (DSBR) provides insight into genome instability, oncogenesis and genome engineering, including disease gene correction. Research into DSBR exploits rare-cutting endonucleases to cleave exogenous reporter constructs integrated into the genome. Multiple reporter constructs have been developed to detect various DSBR pathways.

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The correction of disease-causing mutations by single-strand oligonucleotide-templated DNA repair (ssOR) is an attractive approach to gene therapy, but major improvements in ssOR efficiency and consistency are needed. The mechanism of ssOR is poorly understood but may involve annealing of oligonucleotides to transiently exposed single-stranded regions in the target duplex. In bacteria and yeast it has been shown that ssOR is promoted by expression of Redβ, a single-strand DNA annealing protein from bacteriophage lambda.

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Modulating chromatin through histone methylation orchestrates numerous cellular processes. SETD2-dependent trimethylation of histone H3K36 is associated with active transcription. Here, we define a role for H3K36 trimethylation in homologous recombination (HR) repair in human cells.

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Background: Mutations in the β-globin gene (HBB) cause haemoglobinopathies where current treatments have serious limitations. Gene correction by homologous recombination (HR) is an attractive approach to gene therapy for such diseases and is stimulated by gene-specific endonucleases, including zinc finger nucleases (ZFNs). Customised nucleases targeting HBB have previously been shown to promote HR-mediated HBB modification in 0.

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As proliferating cells transit from interphase into M-phase, chromatin undergoes extensive reorganization, and topoisomerase (topo) IIα, the major isoform of this enzyme present in cycling vertebrate cells, plays a key role in this process. In this study, a human cell line conditional null mutant for topo IIα and a derivative expressing an auxin-inducible degron (AID)-tagged version of the protein have been used to distinguish real mitotic chromosome functions of topo IIα from its more general role in DNA metabolism and to investigate whether topo IIβ makes any contribution to mitotic chromosome formation. We show that topo IIβ does contribute, with endogenous levels being sufficient for the initial stages of axial shortening.

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The EGF receptor (EGFR) is therapeutically targeted by antibodies and small molecules in solid tumors including lung, colorectal, and breast cancer. However, chemotherapy remains important, and efforts to improve efficacy through combination with targeted agents is challenging. This study examined the effects of short and long durations of exposure to the EGFR- and HER2-targeted tyrosine kinase inhibitors (TKI) gefitinib and lapatinib, on induction of cell death and DNA damage by topoisomerase IIα (Topo IIα) poisons, in the SK-Br-3 HER2-amplified breast cancer cell line.

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Cyclin-dependent kinase 1 (Cdk1) controls cell proliferation and is inhibited by promising anticancer agents, but its mode of action and the consequences of its inhibition are incompletely understood. Cdk1 promotes S- and M-phases during the cell-cycle but also suppresses endoreduplication, which is associated with polyploidy and genome instability. The complexity of Cdk1 regulation has made it difficult to determine whether these different roles require different thresholds of kinase activity and whether the surge of activity as inhibitory phosphates are removed at mitotic onset is essential for cell proliferation.

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Type II DNA topoisomerases catalyse DNA double-strand cleavage, passage and re-ligation to effect topological changes. There is considerable interest in elucidating topoisomerase II roles, particularly as these proteins are targets for anti-cancer drugs. Here we uncover a role for topoisomerase IIα in RNA polymerase I-directed ribosomal RNA gene transcription, which drives cell growth and proliferation and is upregulated in cancer cells.

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Topoisomerase II alpha (TOP2A) has a crucial role in proper chromosome condensation and segregation. Here we report the interaction of TOP2A with ataxia telangiectasia mutated (ATM) and its phosphorylation in an ATM-dependent manner after DNA damage. In vitro kinase assay and site-directed mutagenesis studies revealed that serine 1512 is the target of phosphorylation through ATM.

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BCL6 is essential for normal antibody responses and is highly expressed in germinal centre B-cells. Constitutive expression due to chromosomal translocations or mutations of cis-acting regulatory elements contributes to diffuse large B-cell lymphoma. BCL6 expression is therefore tightly regulated in a lineage- and developmental-stage-specific manner, and disruption of normal controls can contribute to lymphomagenesis.

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Eukaryotic type II topoisomerases (Topo II) are implicated in a wide range of cellular processes. Cells in which Topo II protein has been specifically depleted or mutated provide powerful systems for analysing the normal in vivo functions of Topo II proteins and for assessing their roles in various chemotherapy regimens. Summarised here are the ways in which Topo II has been depleted or mutated in animal cells and the type of information gleaned.

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Coadministration of the iron chelator dexrazoxane reduces by 80% the incidence of heart failure in cancer patients treated with anthracyclines. The clinical application of dexrazoxane is limited, however, because its ability to inhibit topoisomerase IIα (TOP2A) is feared to adversely affect anthracycline chemotherapy, which involves TOP2A-mediated generation of DNA double-strand breaks (DSB). Here, we investigated the apoptotic effects of dexrazoxane and the anthracycline doxorubicin, alone and in combination, in a tumor cell line with conditionally regulated expression of TOP2A.

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