scholarly journals Fanconi anemia genes act to suppress a cross-linker-inducible p53- independent apoptosis pathway in lymphoblastoid cell lines

Blood ◽  
1996 ◽  
Vol 87 (3) ◽  
pp. 938-948 ◽  
Author(s):  
FA Kruyt ◽  
LM Dijkmans ◽  
TK van den Berg ◽  
H Joenje
Keyword(s):  
Fanconi Anemia ◽  
Bone Marrow Failure ◽  
Complementation Group ◽  
Dominant Negative ◽  
Bone Marrow Failure Syndrome ◽  
Apoptosis Pathway ◽  
Barr Virus ◽  
Cycle Arrest ◽  
P53 Activation ◽  
Epstein Barr

Hypersensitivity to cross-linking agents such as mitomycin C (MMC) is characteristic of cells from patients suffering from the inherited bone marrow failure syndrome. Fanconi anemia (FA). Here, we link MMC hypersensitivity of Epstein-Barr virus (EBV)-immortalized FA lymphoblasts to a high susceptibility for apoptosis and p53 activation. In MMC-treated FA cells belonging to complementation group C (FA-C), apoptosis followed cell cycle arrest in the G2 phase. In stably transfected FA-C cells, plasmid-driven expression of the wild-type cytoplasmic FAC protein relieved MMC-dependent G2 arrest and suppressed p53 activation. However, in both FA and non-FA lymphoblasts, p53 seemed not to be instrumental in the induction of MMC-dependent apoptosis, since overexpression of a dominant-negative p53 mutant failed to affect cell survival. In addition, no differences in the level of Bcl-2 expression, an inhibitor of apoptosis, were detected between FA and non- FA cells either in the absence or presence of MMC. Our findings suggest that FAC and the other putative FA gene products may function in a yet to be identified p53-independent apoptosis pathway.

scholarly journals Analysis of disease model iPSCs derived from patients with a novel Fanconi anemia-like IBMFS ADH5/ALDH2 deficiency

Blood ◽  
2021 ◽  
Author(s):  
Anfeng Mu ◽  
Asuka Hira ◽  
Akira Niwa ◽  
Mitsujiro Osawa ◽  
Kenichi Yoshida ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Lines ◽  
Fanconi Anemia ◽  
Bone Marrow Failure ◽  
Disease Model ◽  
Dominant Negative ◽  
Bone Marrow Failure Syndrome ◽  
Repair Capacity ◽  
Deficient Cell

We have recently discovered Japanese children with a novel Fanconi anemia-like inherited bone marrow failure syndrome. This disorder is likely caused by the loss of a catabolic system directed toward endogenous formaldehyde, due to biallelic variants in ADH5 combined with a heterozygous ALDH2*2 dominant-negative allele (rs671), which is associated with alcohol-induced Asian flushing. PHA-stimulated lymphocytes from these patients displayed highly increased numbers of spontaneous sister chromatid exchanges (SCEs), reflecting homologous recombination repair of formaldehyde damage. Here we report that, by contrast, patient-derived fibroblasts showed normal levels of SCEs, suggesting that different cell types or conditions generate varying amounts of formaldehyde. To obtain insights about endogenous formaldehyde production and how defects in ADH5/ALDH2 affect human hematopoiesis, we constructed disease model cell lines, including iPS cells (iPSC). We found that ADH5 is the primary defense against formaldehyde, and ALDH2 provides a backup. DNA repair capacity in the ADH5/ALDH2-deficient cell lines can be overwhelmed by exogenous low-dose formaldehyde as indicated by higher levels of DNA damage than FANCD2-deficient cells. Although ADH5/ALDH2-deficient cell lines were healthy and showed stable growth, disease model iPSCs displayed drastically defective cell expansion when stimulated into hematopoietic differentiation in vitro, displaying increased levels of DNA damage. The expansion defect was partially reversed by treatment with a new small molecule termed C1, which is an agonist of ALDH2, thus identifying a potential therapeutic strategy for the patients. We propose that hematopoiesis or lymphocyte blastogenesis may entail formaldehyde generation that necessitates elimination by ADH5/ALDH2 enzymes.

scholarly journals The Fanconi Anemia Group C Gene Product Is Located in Both the Nucleus and Cytoplasm of Human Cells

Blood ◽  
1998 ◽  
Vol 91 (4) ◽  
pp. 1418-1425 ◽  
Author(s):  
Maureen E. Hoatlin ◽  
Tracy A. Christianson ◽  
Winnie W. Keeble ◽  
Adam T. Hammond ◽  
Yu Zhi ◽  
...  
Keyword(s):  
Cell Lines ◽  
Fanconi Anemia ◽  
Immunoblot Analysis ◽  
Subcellular Fractionation ◽  
Complementation Group ◽  
Intracellular Location ◽  
Barr Virus ◽  
Epstein Barr ◽  
Anemia Group ◽  
Transformed Cell Lines

Abstract The Fanconi anemia (FA) complementation group C (FAC) protein gene encodes a cytoplasmic protein with a predicted Mrof 63,000. The protein's function is unknown, but it has been hypothesized that it either mediates resistance to DNA cross-linking agents or facilitates repair after exposure to such factors. The protein also plays a permissive role in the growth of colony-forming unit–granulocyte/macrophage (CFU-GM), burst-forming unit–erythroid (BFU-E), and CFU-erythroid (CFU-E). Attributing a specific function to this protein requires an understanding of its intracellular location. Recognizing that prior study has established the functional importance of its cytoplasmic location, we tested the hypothesis that FAC protein can also be found in the nucleus. Purified recombinant Escherichia coli–derived FAC antigens were used to create antisera able to specifically identify an Mr = 58,000 protein in lysates from human Epstein-Barr virus (EBV)-transformed cell lines by immunoblot analysis. Subcellular fractionation of the cell lysates followed by immunoblot analysis revealed that the majority of the FAC protein was cytoplasmic, as reported previously; however, approximately 10% of FAC protein was reproducibly detected in nuclear fractions. These results were reproducible by two different fractionation methods, and included markers to control for contamination of nuclear fractions by cytoplasmic proteins. Moreover, confocal image analysis of human 293 cells engineered to express FAC clearly demonstrated that FAC protein is located in both cytoplasmic and nuclear compartments, consistent with data obtained from fractionation of the FA cell lines. Finally, complementation of the FAC defect using retroviral-mediated gene transfer resulted in a substantial increase in nuclear FAC protein. Therefore, while cytoplasmic localization of this protein appears to be functionally important, it may also exert some essential nuclear function.

scholarly journals Potential anti-tumor immune response mechanisms of SARS-CoV-2 in lymphomas: can the devil be converted into a boon?

2021 ◽  
Author(s):  
Debmalya Barh ◽  
Sandeep Tiwari ◽  
Lucas Gabriel Rodrigues Gomes ◽  
Marianna E. Weener ◽  
Khalid J. Alzahrani ◽  
...  
Keyword(s):  
Immune Response ◽  
Binding Site ◽  
Therapeutic Potential ◽  
Rare Event ◽  
M Protein ◽  
Barr Virus ◽  
Cycle Arrest ◽  
Ring Complex ◽  
Gamma Tubulin ◽  
Epstein Barr

Abstract Recently, two cases of complete remission of classical Hodgkin lymphoma (cHL) and follicular lymphoma (FL) after SARS-CoV-2 infection were reported. However, the precise molecular mechanism of this rare event is yet to be understood. Here, we hypothesize a potential anti-tumor immune response of SARS-CoV-2 and based on computational approach show that (i) SARS-CoV-2 Spike-RBD may bind to extracellular domains of CD15, CD27, CD45, and CD152 receptors of cHL or FL, (ii) upon internalization, SARS-CoV-2 membrane (M) protein and Orf3a may bind to gamma-tubulin complex component 3 (GCP3) at its tubulin gamma-1 chain (TUBG1) binding site, (iii) M protein may also interact with TUBG1 blocking its binding to GCP3, (iv) both M and Orf3a may render the GCP2-GCP3 lateral binding where M possibly interacts with GCP2 at its GCP3 binding site and Orf3a to GCP3 at its GCP2 interacting residues, (v) interactions of M and Orf3a with these gamma-tubulin ring complex components potentially block the initial process of microtubule nucleation, leading to cell cycle arrest and apoptosis, (vi) Spike-RBD may also interact with and block PD-1 signaling similar to pembrolizumab and nivolumab like monoclonal antibodies and may induce B-cell apoptosis and remission, (vii) finally, the TRADD interacting PVQLSY motif of Epstein-Barr virus LMP-1, that is responsible for NF-kB mediated oncogenesis, potentially interacts with SARS-CoV-2 Mpro, nsp7, nsp10, and Spike proteins and may regulate the LMP-1 mediated cell proliferation. Taken together, our results suggest a possible therapeutic potential of SARS-CoV-2 in proliferative disorders.

scholarly journals Radiosensitization Effect of Nedaplatin on Nasopharyngeal Carcinoma Cells in Different Status of Epstein-Barr Virus Infection

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Li Yin ◽  
Jing Wu ◽  
Jianfeng Wu ◽  
Jinjun Ye ◽  
Xuesong Jiang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Nasopharyngeal Carcinoma ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Epstein Barr Virus ◽  
Barr Virus ◽  
Cycle Arrest ◽  
M Phase ◽  
Epstein Barr ◽  
Mts Assay

This study aims to evaluate the radiosensitization effect of nedaplatin on nasopharyngeal carcinoma (NPC) cell lines with different Epstein-Barr virus (EBV) status. Human NPC cell lines CNE-2 (EBV-negative) and C666 (EBV-positive) were treated with 0–100 μg/mL nedaplatin, and inhibitory effects on cell viability and IC50were calculated by MTS assay. We assessed changes in radiosensitivity of cells by MTS and colony formation assays, and detected the apoptosis index and changes in cell cycle by flow cytometry. MTS assay showed that nedaplatin caused significant cytotoxicity in CNE-2 and C666 cells in a time- and dose-dependent manner. After 24 h, nedaplatin inhibited growth of CNE-2 and C666 cells with IC50values of 34.32 and 63.69 μg/mL, respectively. Compared with radiation alone, nedaplatin enhanced the radiation effect on both cell lines. Nedaplatin markedly increased apoptosis and cell cycle arrest in G2/M phase. Nedaplatin radiosensitized human NPC cells CNE-2 and C666, with a significantly greater effect on the former. The mechanisms of radiosensitization include induction of apoptosis and enhancement of cell cycle arrest in G2/M phase.

scholarly journals Curcumin Inhibits Proliferation of Epstein–Barr Virus-Associated Human Nasopharyngeal Carcinoma Cells by Inhibiting EBV Nuclear Antigen 1 Expression

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Limei Liu ◽  
Jiaomin Yang ◽  
Wuguang Ji ◽  
Chao Wang
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Epstein Barr Virus ◽  
Lytic Replication ◽  
Nuclear Antigen ◽  
Mrna Levels ◽  
Curcumin Treatment ◽  
Antitumor Effects ◽  
Barr Virus ◽  
Cycle Arrest ◽  
Epstein Barr

This investigation aims to study the effect of curcumin on the proliferation, cycle arrest, and apoptosis of Epstein–Barr virus- (EBV-) positive nasopharyngeal carcinoma (NPC) cells. EBV+ NPC cells were subjected to curcumin treatment. The cell viability was evaluated with the CCK-8. Cell cycle and apoptosis were analyzed by flow cytometry analysis. Expression (protein and mRNA) levels were detected with western blotting and quantitative real-time PCR, respectively. Curcumin efficiently reduced the viability of EBV+ NPC cells. Curcumin induced the cycle arrest of the HONE1 and HK1-EBV cells positive for EBV. Moreover, curcumin treatment promoted the NPC cell apoptosis, via the mitochondria- and death receptor-mediated pathways. Furthermore, curcumin decreased the expression of EBNA1 in the HONE1 and HK1-EBV cells and inhibited the transcriptional level of EBNA1 in the HeLa cells. Curcumin induced EBNA1 degradation via the proteasome-ubiquitin pathway. In addition, curcumin inhibited the proliferation of HONE1 and HK1-EBV cells positive for EBV, probably by decreasing the expression level of EBNA1. In both the HONE1 and HK1-EBV cells, curcumin inhibited the EBV latent and lytic replication. Curcumin could reduce the EBNA1 expression and exert antitumor effects against NPC in vitro.

scholarly journals Epstein-Barr Virus-Encoded Bcl-2 Homologue Functions as a Survival Factor in Wp-Restricted Burkitt Lymphoma Cell Line P3HR-1

2009 ◽  
Vol 84 (6) ◽  
pp. 2893-2901 ◽  
Author(s):  
Ami Watanabe ◽  
Seiji Maruo ◽  
Taku Ito ◽  
Miho Ito ◽  
Koichi Ricardo Katsumura ◽  
...  
Keyword(s):  
Cell Line ◽  
Burkitt Lymphoma ◽  
Epstein Barr Virus ◽  
Virus Genome ◽  
Dominant Negative ◽  
Stable Transfection ◽  
Genome Maintenance ◽  
Barr Virus ◽  
Survival Factor ◽  
Epstein Barr

ABSTRACT Burkitt lymphoma (BL) is etiologically associated with Epstein-Barr virus (EBV). EBV-positive BL tumors display two latent forms of infection. One is referred to as latency I infection, in which EBV expresses the virus genome maintenance protein EBNA1 as the only viral protein. The other is referred to as Wp-restricted latency and was recently identified in a subset of BL tumors. In these tumors, EBV expresses EBNA1, EBNA3A, EBNA3B, EBNA3C, a truncated form of EBNA-LP, and the viral Bcl-2 homologue BHRF1, all of which are driven by the BamHI W promoter (Wp). To investigate the role of EBV in Wp-restricted BL, we conditionally expressed a dominant-negative EBNA1 (dnEBNA1) mutant which interrupts the virus genome maintenance function of EBNA1 in the P3HR-1 BL cell line. Induction of dnEBNA1 expression caused loss of the EBV genome and resulted in apoptosis of P3HR-1 cells in the absence of exogenous apoptosis inducers, indicating that P3HR-1 cells cannot survive without EBV. Stable transfection of the BHRF1 gene into P3HR-1 cells rescued the cells from the apoptosis induced by dnEBNA1 expression, whereas stable transfection of truncated EBNA-LP, EBNA3A, or EBNA3C did not. Moreover, knockdown of BHRF1 expression in P3HR-1 cells resulted in increased cell death. These results indicate that EBV is essential for the survival of P3HR-1 cells and that BHRF1 functions as a survival factor. Our finding implies a critical contribution of BHRF1 to the pathogenesis of Wp-restricted BLs.

scholarly journals Fanconi anemia group J mutation abolishes its DNA repair function by uncoupling DNA translocation from helicase activity or disruption of protein-DNA complexes

Blood ◽  
2010 ◽  
Vol 116 (19) ◽  
pp. 3780-3791 ◽  
Author(s):  
Yuliang Wu ◽  
Joshua A. Sommers ◽  
Avvaru N. Suhasini ◽  
Thomas Leonard ◽  
Julianna S. Deakyne ◽  
...  
Keyword(s):  
Dna Repair ◽  
Fanconi Anemia ◽  
Atp Hydrolysis ◽  
Bone Marrow Failure ◽  
Dna Helicase ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Dna Complexes ◽  
Null Cell ◽  
Negative Effect

Abstract Fanconi anemia (FA) is a genetic disease characterized by congenital abnormalities, bone marrow failure, and susceptibility to leukemia and other cancers. FANCJ, one of 13 genes linked to FA, encodes a DNA helicase proposed to operate in homologous recombination repair and replicational stress response. The pathogenic FANCJ-A349P amino acid substitution resides immediately adjacent to a highly conserved cysteine of the iron-sulfur domain. Given the genetic linkage of the FANCJ-A349P allele to FA, we investigated the effect of this particular mutation on the biochemical and cellular functions of the FANCJ protein. Purified recombinant FANCJ-A349P protein had reduced iron and was defective in coupling adenosine triphosphate (ATP) hydrolysis and translocase activity to unwinding forked duplex or G-quadruplex DNA substrates or disrupting protein-DNA complexes. The FANCJ-A349P allele failed to rescue cisplatin or telomestatin sensitivity of a FA-J null cell line as detected by cell survival or γ-H2AX foci formation. Furthermore, expression of FANCJ-A349P in a wild-type background exerted a dominant-negative effect, indicating that the mutant protein interferes with normal DNA metabolism. The ability of FANCJ to use the energy from ATP hydrolysis to produce the force required to unwind DNA or destabilize protein bound to DNA is required for its role in DNA repair.

Sign in / Sign up

Export Citation Format

Share Document