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Genetics
Published in Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple, Basic Urological Sciences, 2021
DNA transcription to RNA (nucleus)Initiation, elongation, termination (Figure 2.3).Mediated by RNA polymerase.Pre-messenger RNA (mRNA) matures to form mature mRNA (see Chapter 1).
Breast Imaging with Radiolabeled Estrogen Receptor Ligands
Published in Raymond Taillefer, Iraj Khalkhali, Alan D. Waxman, Hans J. Biersack, Radionuclide Imaging of the Breast, 2021
Klemens Maria Scheidhauer, Anton Scharl
Estrogens enter tumor cells by passive diffusion and bind with high affinity and specificity to estrogen receptors (ER) [1]. Estrogen receptors are ligand-activated (transcription regulators); the interaction of the ligand-receptor complexes with DNA occurs at special transcription-activating nucleotide sequences, referred to as estrogen-responsive elements (EREs) that lie within the respective promoter regions. The metabolic effect of estrogens takes place through an activation of genes whose gene products control the cell cycle. Those changes occur in DNA transcription that in turn affect cellular protein synthesis [2,3].
Neurologic Side Effects
Published in Ayse Serap Karadag, Berna Aksoy, Lawrence Charles Parish, Retinoids in Dermatology, 2019
Retinoids are either natural or synthetic compounds with functional properties of vitamin A. Retinoid receptors are located in the cell nucleus, similar to steroids, vitamin D, and thyroid hormone receptors (12). Alterations in DNA transcription is the primary mechanism of their biologic effects. In binding to the regulatory regions of DNA, they modify the transcription of many genes. Retinoids may affect cell growth and differentiation, immunomodulation, tumor promotion, and malignant potential of cells (13).
Further understanding of glioma mechanisms of pathogenesis: implications for therapeutic development
Published in Expert Review of Anticancer Therapy, 2020
Michael Ruff, Sani Kizilbash, Jan Buckner
PARP inhibition in MGMT promoter-methylated glioblastoma may be a viable strategy to exploit further the reduced DNA-repair capacity in the setting of coincident TMZ chemotherapy. PARP (poly (ADP-ribose) polymerases) are enzymes that catalyze the transfer of ADP-ribose to target proteins – playing a critical role in DNA repair in addition to DNA transcription, replication, recombination and chromatin modulation. In tumors with defective homologous recombination mechanisms, PARP-mediated DNA repair may be a mechanism of escape and cell survival [28]. As such, PARP inhibitors may also increase tumor sensitivity to DNA-damaging agents or push cells with defective homologous recombination (e.g., BRCA1 mutations) toward apoptosis. Recently, a clinical trial of patients with MGMT-promoter unmethylated glioblastoma treated with veliparib in addition to standard therapies in the upfront setting was underwhelming [29]. A current study (NCT02152982) utilizing veliparib as a PARP inhibitor in MGMT-promoter methylated GBM is underway. This strategy may be more effective in patients with relatively deficient DNA repair (e.g., MGMT-methylated) than in the unmethylated group. Additionally, PARP inhibitors may be a rational treatment approach in IDH-mutated tumors as well (discussed further below).
Association of small-fiber polyneuropathy with three previously unassociated rare missense SCN9A variants
Published in Canadian Journal of Pain, 2020
Mary A. Kelley, Anne Louise Oaklander
Gene panels and whole exome sequencing can miss copy number variants and chromosomal rearrangements such as repeat expansions, insertions, deletions, and some translocations. Another limitation is that they miss effects caused by alterations in noncoding DNA sequences, including some that modulate DNA transcription and translation. Variants in non-protein-coding regions sometimes convey harm by altering biophysical properties of RNA genes or microRNAs to alter transcription or otherwise deter normal cell functioning.45,47 In addition, mitochondrial mutations, which are not captured, can be salient for small fiber and other polyneuropathies, including those associated with multiple lipomas.48–52 Whole genome sequencing will eventually replace gene panels and whole exome sequencing as prices continue to drop and evidence of its value increases.53
The potential of circulating cell free RNA as a biomarker in cancer
Published in Expert Review of Molecular Diagnostics, 2019
Ka Wan Emily Cheung, Sin-yu Rachel Choi, Lok Ting Claire Lee, Nga Lam Ella Lee, Hin Fung Tsang, Yin Tung Cheng, William Chi Shing Cho, Elaine Yue Ling Wong, Sze Chuen Cesar Wong
mRNAs are recognized as the protein-coding transcripts that hold information generated from DNA transcription inside the cell nucleus, which then undergo multiple processes, including 5ʹ methyl capping, splicing of intronic regions, and 3ʹ polyadenylation to achieve mRNA maturation [109]. Consequently, mRNAs reflect the state of genome and homeostatic state in cells. Under normal circumstances, mature mRNAs then travel through the nuclear pore to the cell cytoplasm for translation of proteins or are degraded by cellular mechanisms [109]. However, mRNAs have been detected in the circulation, which are thought to be associated with cell lysis through normal cell turnover or cellular excretion, of which the highly degradative ccfRNA molecules are believed to be packaged in order to avoid RNase degradation [110]. Although the detailed mechanisms of how RNAs enter the circulation, how they are stabilized and taken up by cells are currently unknown, ongoing research highly suggests that ccfRNAs can be potential cancer biomarkers [110].