Transcription elongation defects link oncogenic SF3B1 mutations to targetable alterations in chromatin landscape.

Transcription and splicing of pre-messenger RNA are closely coordinated, but how this functional coupling is disrupted in human diseases remains unexplored. Using isogenic cell lines, patient samples, and a mutant mouse model, we investigated how cancer-associated mutations in SF3B1 alter transcription. We found that these mutations reduce the elongation rate of RNA polymerase II (RNAPII) along gene bodies and its density at promoters.

The FANCI/FANCD2 complex links DNA damage response to R-loop regulation through SRSF1-mediated mRNA export.

Fanconi anemia (FA) is characterized by congenital abnormalities, bone marrow failure, and cancer susceptibility. The central FA protein complex FANCI/FANCD2 (ID2) is activated by monoubiquitination and recruits DNA repair proteins for interstrand crosslink (ICL) repair and replication fork protection. Defects in the FA pathway lead to R-loop accumulation, which contributes to genomic instability.

Mechanism of PARP inhibitor resistance and potential overcoming strategies.

PARP inhibitors (PARPi) are a kind of cancer therapy that targets poly (ADP-ribose) polymerase. PARPi is the first clinically approved drug to exert synthetic lethality by obstructing the DNA single-strand break repair process. Despite the significant therapeutic effect in patients with homologous recombination (HR) repair deficiency, innate and acquired resistance to PARPi is a main challenge in the clinic.

Direct stimulation of de novo nucleotide synthesis by O-GlcNAcylation.

O-linked β-N-acetyl glucosamine (O-GlcNAc) is at the crossroads of cellular metabolism, including glucose and glutamine; its dysregulation leads to molecular and pathological alterations that cause diseases. Here we report that O-GlcNAc directly regulates de novo nucleotide synthesis and nicotinamide adenine dinucleotide (NAD) production upon abnormal metabolic states. Phosphoribosyl pyrophosphate synthetase 1 (PRPS1), the key enzyme of the de novo nucleotide synthesis pathway, is O-GlcNAcylated by O-GlcNAc transferase (OGT), which triggers PRPS1 hexamer formation and relieves nucleotide product-mediated feedback inhibition, thereby boosting PRPS1 activity.

Transcription elongation defects link oncogenic splicing factor mutations to targetable alterations in chromatin landscape.

Unlabelled: Transcription and splicing of pre-messenger RNA are closely coordinated, but how this functional coupling is disrupted in human disease remains unexplored. Here, we investigated the impact of non-synonymous mutations in SF3B1 and U2AF1, two commonly mutated splicing factors in cancer, on transcription. We find that the mutations impair RNA Polymerase II (RNAPII) transcription elongation along gene bodies leading to transcription-replication conflicts, replication stress and altered chromatin organization.

An In Vivo Model for Elucidating the Role of an Erythroid-Specific Isoform of Nuclear Export Protein Exportin 7 (Xpo7) in Murine Erythropoiesis.

Erythroid nuclear condensation is a complex process in which compaction to one-tenth its original size occurs in an active nucleus simultaneously undergoing transcription and cell division. We previously found that the nuclear exportin Exportin7 (Xpo7), which is erythroid- specific and highly induced during terminal erythropoiesis, facilitates nuclear condensation. We also identified a previously unannotated, erythroid-specific isoform of Xpo7 (Xpo7B) containing a novel first exon Xpo7-1b expressed only in late Ter119 erythroblasts.

Homologous Recombination Repair in Biliary Tract Cancers: A Prime Target for PARP Inhibition?

Biliary tract cancers (BTCs) are a heterogeneous group of malignancies that make up ~7% of all gastrointestinal tumors. It is notably aggressive and difficult to treat; in fact, >70% of patients with BTC are diagnosed at an advanced, unresectable stage and are not amenable to curative therapy. For these patients, chemotherapy has been the mainstay treatment, providing an inadequate overall survival of less than one year.

Regulation of Chemosensitivity in Human Medulloblastoma Cells by p53 and the PI3 Kinase Signaling Pathway.

In medulloblastoma, p53 expression has been associated with chemoresistance and radiation resistance and with poor long-term outcomes in the -mutated sonic hedgehog, MYC-p53, and p53-positive medulloblastoma subgroups. We previously established a direct role for p53 in supporting drug resistance in medulloblastoma cells with high basal protein expression levels (D556 and DAOY). We now show that genetic suppression in medulloblastoma cells with low basal p53 protein expression levels (D283 and UW228) significantly reduced drug responsiveness, suggesting opposing roles for low p53 protein expression levels.

Is Essential for Primitive Erythropoiesis.

Congenital dyserythropoietic anemia type I (CDA I) is an autosomal recessive disease characterized by moderate to severe macrocytic anemia and pathognomonic morphologic abnormalities of the erythroid precursors, including spongy heterochromatin. The disease is mainly caused by mutations in (encoding for Codanin-1). No patients with homozygous null type mutations have been described, and mouse null mutants die during early embryogenesis prior to the initiation of erythropoiesis.

Bone marrow transplant using fludarabine-based reduced intensity conditioning regimen with in vivo T cell depletion in patients with Fanconi anemia.

FA is the most common cause of inherited BMF syndromes. The only cure for BMF in FA remains HSCT. Due to DNA instability in FA, RIC has been used to decrease immediate and late complications of HSCT.

Patterns of medication use at end of life by pediatric inpatients with cancer.

Objective: To describe medication utilization patterns by pediatric inpatients with cancer during their last week of life.

Methods: This retrospective study used data from the Vizient Clinical Database/Resource Manager, a national compilation of clinical and resource use data from over 100 academic medical centers and affiliates. Patients (0-21 years) with malignancy who died during hospitalization (2010-2017) were included (N = 1659).

The DNA-binding activity of USP1-associated factor 1 is required for efficient RAD51-mediated homologous DNA pairing and homology-directed DNA repair.

USP1-associated factor 1 (UAF1) is an integral component of the RAD51-associated protein 1 (RAD51AP1)-UAF1-ubiquitin-specific peptidase 1 (USP1) trimeric deubiquitinase complex. This complex acts on DNA-bound, monoubiquitinated Fanconi anemia complementation group D2 (FANCD2) protein in the Fanconi anemia pathway of the DNA damage response. Moreover, RAD51AP1 and UAF1 cooperate to enhance homologous DNA pairing mediated by the recombinase RAD51 in DNA repair via the homologous recombination (HR) pathway.

Total knee arthroplasty in hemophilia A.

Hemophilia A is a rare genetic disorder involving a deficiency of clotting factor VIII. Coagulation factor replacement therapy has prolonged the life expectancy of patients with hemophilia, but recurrent hemarthrosis of major joints is often a common occurrence. Therefore, orthopaedic adult reconstructive surgeons increasingly encounter hemophilic arthropathy in young adults and consider treating with total joint arthroplasty.

DNA requirement in FANCD2 deubiquitination by USP1-UAF1-RAD51AP1 in the Fanconi anemia DNA damage response.

Fanconi anemia (FA) is a multigenic disease of bone marrow failure and cancer susceptibility stemming from a failure to remove DNA crosslinks and other chromosomal lesions. Within the FA DNA damage response pathway, DNA-dependent monoubiquitinaton of FANCD2 licenses downstream events, while timely FANCD2 deubiquitination serves to extinguish the response. Here, we show with reconstituted biochemical systems, which we developed, that efficient FANCD2 deubiquitination by the USP1-UAF1 complex is dependent on DNA and DNA binding by UAF1.

Binding of FANCI-FANCD2 Complex to RNA and R-Loops Stimulates Robust FANCD2 Monoubiquitination.

Fanconi anemia (FA) is characterized by developmental abnormalities, bone marrow failure, and cancer predisposition. FA cells are hypersensitive to DNA replicative stress and accumulate co-transcriptional R-loops. Here, we use the Damage At RNA Transcription assay to reveal colocalization of FANCD2 with R-loops in a highly transcribed genomic locus upon DNA damage.

Reprogramming human T cell function and specificity with non-viral genome targeting.

Decades of work have aimed to genetically reprogram T cells for therapeutic purposes using recombinant viral vectors, which do not target transgenes to specific genomic sites. The need for viral vectors has slowed down research and clinical use as their manufacturing and testing is lengthy and expensive. Genome editing brought the promise of specific and efficient insertion of large transgenes into target cells using homology-directed repair.

Chimeric antigen receptor T cell (CAR-T) immunotherapy for solid tumors: lessons learned and strategies for moving forward.

Recently, the US Food and Drug Administration (FDA) approved the first chimeric antigen receptor T cell (CAR-T) therapy for the treatment CD19-positive B cell acute lymphoblastic leukemia. While CAR-T has achieved remarkable success in the treatment of hematopoietic malignancies, whether it can benefit solid tumor patients to the same extent is still uncertain. Even though hundreds of clinical trials are undergoing exploring a variety of tumor-associated antigens (TAA), no such antigen with comparable properties like CD19 has yet been identified regarding solid tumors CAR-T immunotherapy.

NCCN Guidelines Insights: Acute Lymphoblastic Leukemia, Version 1.2017.

The prognosis for patients with newly diagnosed acute lymphoblastic leukemia (ALL) has improved with the use of more intensive chemotherapy regimens, tyrosine kinase inhibitors, targeted agents, and allogeneic hematopoietic cell transplantation. However, the management of relapsed or refractory (R/R) ALL remains challenging and prognosis is poor. The NCCN Guidelines for ALL provide recommendations on standard treatment approaches based on current evidence.

A novel role for non-ubiquitinated FANCD2 in response to hydroxyurea-induced DNA damage.

This corrects the article DOI: 10.1038/onc.2015.

Promotion of RAD51-Mediated Homologous DNA Pairing by the RAD51AP1-UAF1 Complex.

The UAF1-USP1 complex deubiquitinates FANCD2 during execution of the Fanconi anemia DNA damage response pathway. As such, UAF1 depletion results in persistent FANCD2 ubiquitination and DNA damage hypersensitivity. UAF1-deficient cells are also impaired for DNA repair by homologous recombination.