Homologous recombination (HR) is an important mechanism for repairing DNA double-strand breaks (DSBs) and preserving genome integrity. Pathogenic mutations in the HR proteins BRCA2 and the RAD51 paralogs predispose individuals to breast, ovarian, pancreatic, and prostate cancer. The RAD51 paralogs: RAD51B, RAD51C, RAD51D, XRCC2, and XRCC3 form two complexes RAD51B-RAD51C-RAD51D-XRCC2 (BCDX2) and RAD51C-XRCC3 (CX3).
View Article and Find Full Text PDFPoly (ADP-ribose) glycohydrolase (PARG) inhibitors are currently under clinical development for the treatment of DNA repair-deficient cancers; however, their precise mechanism of action is still unclear. Here, we report that PARG inhibition leads to excessive PARylated poly (ADP-ribose) polymerase 1 (PARP1) reducing the ability of PARP1 to properly localize to sites of DNA damage. Strikingly, the mis-localized PARP1 accumulates as aggregates throughout the nucleus.
View Article and Find Full Text PDFBackground: An effective vaccine is required to end the HIV pandemic. We evaluated the safety and immunogenicity of a DNA (DNA-HIV-PT123) vaccine with low- or high-dose bivalent (TV1.C and 1086.
View Article and Find Full Text PDFBRCA2 is a tumor suppressor protein responsible for safeguarding the cellular genome from replication stress and genotoxicity, but the specific mechanism(s) by which this is achieved to prevent early oncogenesis remains unclear. Here, we provide evidence that BRCA2 acts as a critical suppressor of head-on transcription-replication conflicts (HO-TRCs). Using Okazaki-fragment sequencing (Ok-seq) and computational analysis, we identified origins (dormant origins) that are activated near the transcription termination sites (TTS) of highly expressed, long genes in response to replication stress.
View Article and Find Full Text PDFThe optimal timing of immunosuppression and post-transplantation cyclophosphamide (PTCy) in haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is unknown. However, cytokine release syndrome (CRS) following haplo-HSCT is associated with worse transplantation outcomes, and the incidence of CRS may be affected by the timing of immunosuppression and PTCy. In this study, we compared CRS and other transplantation outcomes in 2 cohorts receiving different immunosuppression and PTCy schedules following haplo-HSCT.
View Article and Find Full Text PDFMutations in the breast cancer susceptibility gene, , greatly increase an individual's lifetime risk of developing breast and ovarian cancers. suppresses tumor formation by potentiating DNA repair via homologous recombination. Central to recombination is the assembly of a RAD51 nucleoprotein filament, which forms on single-stranded DNA (ssDNA) generated at or near the site of chromosomal damage.
View Article and Find Full Text PDFPathogenic mutations in the BRCA2 tumor suppressor gene predispose to breast, ovarian, pancreatic, prostate, and other cancers. BRCA2 maintains genome stability through homology-directed repair (HDR) of DNA double-strand breaks (DSBs) and replication fork protection. Nonsense or frameshift mutations leading to truncation of the BRCA2 protein are typically considered pathogenic; however, missense mutations resulting in single amino acid substitutions can be challenging to functionally interpret.
View Article and Find Full Text PDFThe BRCA2 germline missense variant, R3052W, resides in the DNA binding domain and has been previously classified as a pathogenic allele. In this study, we sought to determine how R3052W alters the cellular functions of BRCA2 in the DNA damage response. The BRCA2 R3052W mutated protein exacerbates genome instability, is unable to rescue homology-directed repair, and fails to complement cell survival following exposure to PARP inhibitors and crosslinking drugs.
View Article and Find Full Text PDFObjectives: Fecal pancreatic elastase (PE) assays are screening tests for exocrine pancreatic insufficiency (EPI). We analytically evaluated a new PE assay and retrospectively analyzed data from an academic hospital and reference laboratory to understand the clinical utility.
Methods: Forty stool samples with different PE concentrations were tested on the ScheBo enzyme-linked immunosorbent assay (ELISA) versus DiaSorin LIAISON immunoassay; a simple-to-use extraction device was assessed.
DNA fiber combing is a versatile technique that provides insight into replication fork dynamics at single-molecule resolution. DNA fibers are bound to silanized coverslips and combed, which straightens and aligns the fibers along a single axis. Here, we present a DNA fiber combing protocol that does not use commercial kits; we detail the steps to prepare all materials, reagents, and silanized coverslips.
View Article and Find Full Text PDFChimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of relapsed/refractory B-cell malignancies. However, there is no data on the safety and efficacy of CAR T-cell therapy in patients with end stage renal disease (ESRD) requiring dialysis. In this report, we present two patients with DLBCL and ESRD who were successfully treated with different CAR T-cell products.
View Article and Find Full Text PDFGenes (Basel)
August 2021
The gene encodes DNA polymerase θ, a 2590 amino acid protein product harboring DNA-dependent ATPase, template-dependent DNA polymerase, dNTP-dependent endonuclease, and 5'-dRP lyase functions. Polymerase θ participates at an essential step of a DNA double-strand break repair pathway able to join 5'-resected substrates by locating and pairing microhomologies present in 3'-overhanging single-stranded tails, cleaving the extraneous 3'-DNA by dNTP-dependent end-processing, before extending the nascent 3' end from the microhomology annealing site. Metazoans require polymerase θ for full resistance to DNA double-strand break inducing agents but can survive knockout of the gene.
View Article and Find Full Text PDFObjectives: To compare the PhiCal assay (CALPRO), the first US Food and Drug Administration-approved assay for fecal calprotectin, to 4 next-generation assays.
Methods: Stool samples from 50 patients were selected, and relevant clinical information was collected. Comparisons were performed using the PhiCal, fCAL turbo (BÜHLMANN), LIAISON Calprotectin (DiaSorin), QUANTA Lite Calprotectin ELISA (Inova Diagnostics), and Calprotectin Chemiluminescence ELISA (ALPCO) assays.
Alpha Thalassemia/Mental Retardation Syndrome X-Linked (ATRX) is mutated frequently in gliomas and represents a potential target for cancer therapies. ATRX is known to function as a histone chaperone that helps incorporate histone variant, H3.3, into the genome.
View Article and Find Full Text PDFPathological mutations in homology-directed repair (HDR) genes impact both future cancer risk and therapeutic options for patients. HDR is a high-fidelity DNA repair pathway for resolving DNA double-strand breaks throughout the genome. BRCA2 is an essential protein that mediates the loading of RAD51 onto resected DNA breaks, a key step in HDR.
View Article and Find Full Text PDFObjective: This study evaluated costs and healthcare utilization associated with a culturally-sensitive, medical and education program for pediatric Latino patients with type 1 diabetes.
Research Design And Methods: Program participants included Latino children ages 1-20 years old diagnosed with type 1 diabetes (n = 57). Control subjects with type 1 diabetes were matched by age, sex, and zip code to intervention participants from the Colorado All Payer Claims Database.
Background: Fecal calprotectin (FC) is a screening test for intestinal inflammation, and often used by clinicians to help identify and monitor patients with inflammatory bowel disease (IBD). Improvements in FC assays include moving to more automated immunoassays compared to ELISAs and simple-to-use extraction devices compared to manual weighing for the extraction process.
Methods: A method comparison was performed between the PhiCal ELISA and LIAISON immunoassay for 53 stool samples, and the screening results were compared to the gold standard endoscopy with biopsy results.
Cancers with hereditary defects in homologous recombination rely on DNA polymerase θ (pol θ) for repair of DNA double-strand breaks. During end joining, pol θ aligns microhomology tracts internal to 5'-resected broken ends. An unidentified nuclease trims the 3' ends before synthesis can occur.
View Article and Find Full Text PDFMethods Mol Biol
March 2021
The homologous recombination (HR) pathway maintains genomic integrity by repairing DNA double-strand breaks (DSBs), single-strand DNA gaps, and collapsed replication forks. The process of HR involves strand invasion, homology search, and DNA strand exchange between paired DNA molecules. HR is critical for the high-fidelity repair of DNA DSBs in mitotic cells and for the exchange of genetic information during meiosis.
View Article and Find Full Text PDFThe efficient maintenance of genome integrity in the face of cellular stress is vital to protect against human diseases such as cancer. DNA replication, chromatin dynamics, cellular signaling, nuclear architecture, cell cycle checkpoints, and other cellular activities contribute to the delicate spatiotemporal control that cells utilize to regulate and maintain genome stability. This perspective will highlight DNA double-strand break (DSB) repair pathways in human cells, how DNA repair failures can lead to human disease, and how PARP inhibitors have emerged as a novel clinical therapy to treat homologous recombination-deficient tumors.
View Article and Find Full Text PDFBackground: The Pox-Protein Public-Private Partnership is performing a suite of trials to evaluate the bivalent subtype C envelope protein (TV1.C and 1086.C glycoprotein 120) vaccine in the context of different adjuvants and priming agents for human immunodeficiency virus (HIV) type 1 (HIV-1) prevention.
View Article and Find Full Text PDFBACKGROUNDRV144 is the only preventive HIV vaccine regimen demonstrating efficacy in humans. Attempting to build upon RV144 immune responses, we conducted a phase 1, multicenter, randomized, double-blind trial to assess the safety and immunogenicity of regimens substituting the DNA-HIV-PT123 (DNA) vaccine for ALVAC-HIV in different sequences or combinations with AIDSVAX B/E (protein).METHODSOne hundred and four HIV-uninfected participants were randomized to 4 treatment groups (T1, T2, T3, and T4) and received intramuscular injections at 0, 1, 3, and 6 months (M): T1 received protein at M0 and M1 and DNA at M3 and M6; T2 received DNA at M0 and M1 and protein at M3 and M6; T3 received DNA at M0, M1, M3, and M6 with protein coadministered at M3 and M6; and T4 received protein and DNA coadministered at each vaccination visit.
View Article and Find Full Text PDFOne of the most successful HIV vaccines to date, the RV144 vaccine tested in Thailand, demonstrated correlates of protection including cross-clade V1V2 immunoglobulin G (IgG) breadth, Env-specific CD4 T cell polyfunctionality, and antibody-dependent cellular cytotoxicity (ADCC) in vaccinees with low IgA binding. The HIV Vaccine Trials Network (HVTN) 097 trial evaluated this vaccine regimen in South Africa, where clade C HIV-1 predominates. We compared cellular and humoral responses at peak and durability immunogenicity time points in HVTN 097 and RV144 vaccinee samples, and evaluated vaccine-matched and cross-clade immune responses.
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