Browsing by Subject "Fanconi anemia (FA)"

Now showing 1 - 4 of 4
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    Fanconi anemia and the cell cycle: new perspectives on aneuploidy
    (H1, 2014-04-01) Nalepa, Grzegorz; Clapp, D. Wade; Pediatrics, School of Medicine
    Fanconi anemia (FA) is a complex heterogenic disorder of genomic instability, bone marrow failure, cancer predisposition, and congenital malformations. The FA signaling network orchestrates the DNA damage recognition and repair in interphase as well as proper execution of mitosis. Loss of FA signaling causes chromosome instability by weakening the spindle assembly checkpoint, disrupting centrosome maintenance, disturbing resolution of ultrafine anaphase bridges, and dysregulating cytokinesis. Thus, the FA genes function as guardians of genome stability throughout the cell cycle. This review discusses recent advances in diagnosis and clinical management of Fanconi anemia and presents the new insights into the origins of genomic instability in FA. These new discoveries may facilitate the development of rational therapeutic strategies for FA and for FA-deficient malignancies in the general population.
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    Interleukin 8/KC enhances G-CSF induced hematopoietic stem/progenitor cell mobilization in Fancg deficient mice
    (AME Publishing Company, 2014) Li, Yan; Xing, Wen; He, Yong-Zheng; Chen, Shi; Rhodes, Steven D.; Yuan, Jin; Zhou, Yuan; Shi, Jun; Bai, Jie; Zhang, Feng-Kui; Yuan, Wei-Ping; Cheng, Tao; Xu, Ming-Jiang; Yang, Feng-Chun; Department of Pediatrics, IU School of Medicine
    BACKGROUND: Fanconi anemia (FA) is a heterogeneous genetic disorder characterized by a progressive bone marrow aplasia, chromosomal instability, and acquisition of malignancies. Successful hematopoietic cell transplantation (HCT) for FA patients is challenging due to hypersensitivity to DNA alkylating agents and irradiation of FA patients. Early mobilization of autologous stem cells from the bone marrow has been thought to be ideal prior to the onset of bone marrow failure, which often occurs during childhood. However, the markedly decreased response of FA hematopoietic stem cells to granulocyte colony-stimulating factor (G-CSF) is circumventive of this autologous HCT approach. To-date, the mechanism for defective stem cell mobilization in G-CSF treated FA patients remains unclear. METHODS: Fancg heterozygous (Fancg (+/-)) mice utilized in these studies. Student's t-test and one-way ANOVA were used to evaluate statistical differences between WT and Fancg (-/-) cells. Statistical significance was defined as P values less than 0.05. RESULTS: Fancg deficient (Fancg (-/-)) mesenchymal stem/progenitor cells (MSPCs) produce significant lower levels of KC, an interleukin-8 (IL-8) related chemoattractant protein in rodents, as compared to wild type cells. Combinatorial administration of KC and G-CSF significantly increased the mobilization of hematopoietic stem/progenitor cells (HSPCs) in Fancg (-/-) mice. CONCLUSIONS: In summary, our results suggest that KC/IL-8 could be proved useful in the synergistic mobilization of FA HSPCs in combination with G-CSF.
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    Numbers of long-term hematopoietic stem cells from bone marrow of fanca and fancc knockout mice can be greatly enhanced by their collection and processing in physioxia conditions
    (Elsevier, 2021) Broxmeyer, Hal E.; Capitano, Maegan L.; Cooper, Scott; Potchanant, Elizabeth Sierra; Clapp, D. Wade; Microbiology and Immunology, School of Medicine
    Fanconi anemia (FA) is associated with bone marrow failure. Bone marrow (BM) from patients with FA and fanca−/− and fancc−/− mice are deficient in hematopoietic stem (HSCs) and progenitor cells (HPCs). Decreased HSCs/HPCs compromise their use in human and mouse hematopoietic cell transplantation (HCT) and gene therapy to correct genetic defects causing FA. We reported increased collection of HSCs from mouse bone marrow and mobilized peripheral blood, and human cord blood of normal donors after collection/processing in low (3%) oxygen (physioxia). We assessed comparative contents of long-term (LT)-HSCs from BM of fanca−/− and fancc−/− when collected/processed at 3% O2, in order to negate effects of extra physiological shock stress (EPHOSS) induced by collection/processing in ambient air. Collection/processing of BM from fanca−/− and fancc−/− mice in physioxia demonstrated a ≥3-fold increase in LT-HSCs compared to that in ambient air. This was associated with decreased phenotypic multipotential progenitor cells and functional granulocyte macrophage, erythroid, and multi-potential progenitors, results similar to that for BM from normal donor mice. Increased collection of HSCs could have clinical applicability for gene therapy and HCT.
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    Replication gaps are a key determinant of PARP inhibitor synthetic lethality with BRCA deficiency
    (Cell Press, 2021) Cong, Ke; Peng, Min; Kousholt, Arne Nedergaard; Lee, Wei Ting C.; Lee, Silviana; Nayak, Sumeet; Krais, John; VanderVere-Carozza, Pamela S.; Pawelczak, Katherine S.; Calvo, Jennifer; Panzarino, Nicholas J.; Turchi, John J.; Johnson, Neil; Jonkers, Jos; Rothenberg, Eli; Cantor, Sharon B.; Medicine, School of Medicine
    Mutations in BRCA1 or BRCA2 (BRCA) is synthetic lethal with poly(ADP-ribose) polymerase inhibitors (PARPi). Lethality is thought to derive from DNA double-stranded breaks (DSBs) necessitating BRCA function in homologous recombination (HR) and/or fork protection (FP). Here, we report instead that toxicity derives from replication gaps. BRCA1- or FANCJ-deficient cells, with common repair defects but distinct PARPi responses, reveal gaps as a distinguishing factor. We further uncouple HR, FP, and fork speed from PARPi response. Instead, gaps characterize BRCA-deficient cells, are diminished upon resistance, restored upon resensitization, and, when exposed, augment PARPi toxicity. Unchallenged BRCA1-deficient cells have elevated poly(ADP-ribose) and chromatin-associated PARP1, but aberrantly low XRCC1 consistent with defects in backup Okazaki fragment processing (OFP). 53BP1 loss resuscitates OFP by restoring XRCC1-LIG3 that suppresses the sensitivity of BRCA1-deficient cells to drugs targeting OFP or generating gaps. We highlight gaps as a determinant of PARPi toxicity changing the paradigm for synthetic lethal interactions.