Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To induce cell death in osteosarcoma, a murine osteosarcoma clone, DOS C14 was exposed to: i) topoisomerase II-reactive epipodophyllotoxin, etoposide (ETO); ii) glucocorticoid analogue, dexamethasone (DEX); and iii) ultraviolet light (UV) irradiation. In MTT assay, fifty micromolar ETO, 100 mu M DEX and UV irradiation for 90 min reduced the cell number to 20% of that of the control. The cytotoxic effects of ETO and DEX were dose-dependent, while those of UV irradiation were time-dependent. Endonuclease cleavage of DNA into internucleosomal fragments was not recognized on DOS C14 osteosarcoma treated with 50 mu M ETO, 100 mu M DEX or UV irradiation. Aurintricarboxylic acid (ATA) also failed to inhibit the reduction in the number of viable cells. However, DNA from DOS C14 osteosarcoma cells exposed to 1 h UV irradiation showed smearing DNA fragments after treatment with S1 endonuclease, while such single strand modification was not detected in DNA extracted from cells exposed to ETO or DEX. On the other hand, pulse field gel electrophoresis revealed that cleavage of DNA into high molecular weight fragments estimated as 50-150 kilobase pairs (kbp) with a peak of 100 kbp was found in DOS C14 osteosarcoma cells exposed to 50 mu M ETO and 100 mu M DEX. The cytotoxicity of ETO and DEX was reduced by okadaic acid, while UV-induced cytotoxicity was not reduced by okadaic acid. Furthermore, okadaic acid inhibited the formation of high molecular weight DNA fragments in a dose-dependent manner. These results suggest that two types of DNA degradation exist in osteosarcoma death; one is random breakage of DNA, and the other is large DNA fragmentation, which may be produced by an activation of putative ATA-insensitive and okadaic acid-sensitive endonuclease.
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PMID:Different types of DNA cleavage involved in osteosarcoma cell death. 2154 94

Tumor angiogenesis contributes to inferior prognosis in osteosarcoma. Apurinic/apyrimidinic endonuclease 1 (APE1) and fibroblast growth factor 2 (FGF2) and its receptor 3 (FGFR3) signaling pathway plays an important role in the angiogenic process. In this study we observed that high expression of APE1, FGF2 and FGFR3, and microvessel density are positively correlated with poor prognosis of osteosarcoma patients. Furthermore, the Cox model showed that the tumor size, FGF2 and its receptor 3 (FGFR3), and microvessel density were adverse prognostic factors. Based on our clinical data, and the fact that APE1 is involved in tumor angiogenesis, we hypothesize that it is very likely that APE1 may indirectly promote angiogenesis by upregulating fibroblast FGF2 and FGFR3. Our preliminary data show small interfering RNA-mediated silence of APE1 experiments, which further supports this hypothesis. APE1-small interfering RNA significantly inhibited tumor angiogenesis by downregulating in vitro expression of FGF2 and FGFR3 in human umbilical vein endothelial cells in Matrigel tube formation assay, and further inhibited tumor growth in vivo in a mouse xenograft model. Thus, the proposed APE1-FGF2 and FGFR3 pathway may provide a novel mechanism for regulation of FGF2 and FGFR3 by APE1 in tumor angiogenesis.
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PMID:Apurinic/apyrimidinic endonuclease 1 induced upregulation of fibroblast growth factor 2 and its receptor 3 induces angiogenesis in human osteosarcoma cells. 2432 8

CRISPR is a genome-editing platform that makes use of the bacterially-derived endonuclease Cas9 to introduce DNA double-strand breaks at precise locations in the genome using complementary guide RNAs. We developed a nuclear domain knock-in screen, whereby the insertion of a gene encoding the green fluorescent protein variant Clover is inserted by Cas9-mediated homology directed repair (HDR) within the first exon of genes that are required for the structural integrity of subnuclear domains such as the nuclear lamina and promyelocytic leukemia nuclear bodies (PML NBs). Using this approach, we compared strategies for enhancing CRISPR-mediated HDR, focusing on known genes and small molecules that impact non-homologous end joining (NHEJ) and homologous recombination (HR). Ultimately, we identified the small molecule RS-1 as a potent enhancer of CRISPR-based genome editing, enhancing HDR 3- to 6-fold depending on the locus and transfection method. We also characterized U2OS human osteosarcoma cells expressing Clover-tagged PML and demonstrate that this strategy generates cell lines with PML NBs that are structurally and functionally similar to bodies in the parental cell line. Thus, the nuclear domain knock-in screen that we describe provides a simple means of rapidly evaluating methods and small molecules that have the potential to enhance Cas9-mediated HDR.
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PMID:Nuclear domain 'knock-in' screen for the evaluation and identification of small molecule enhancers of CRISPR-based genome editing. 2642 72

Human RecQ-like helicase 4 (RECQL4) plays crucial roles in replication initiation and DNA repair; however, the contextual regulation of its unwinding activity is not fully described. Mutations in RECQL4 have been linked to three diseases including Rothmund-Thomson syndrome, which is characterized by osteoskeletal deformities, photosensitivity, and increased osteosarcoma susceptibility. Understanding regulation of RECQL4 helicase activity by interaction partners will allow deciphering its role as an enzyme and a signaling cofactor in different cellular contexts. We became interested in studying the interaction of RECQL4 with ribosomal protein S3 (RPS3) because previous studies have shown that RPS3 activity is sometimes associated with phenotypes mimicking those of mutated RECQL4. RPS3 is a small ribosomal protein that also has extraribosomal functions, including apurnic-apyrimidinic endonuclease-like activity suggested to be important during DNA repair. Here, we report a functional and physical interaction between RPS3 and RECQL4 and show that this interaction may be enhanced during cellular stress. We show that RPS3 inhibits ATPase, DNA binding, and helicase activities of RECQL4 through their direct interaction. Further domain analysis shows that N-terminal 1-320 amino acids of RECQL4 directly interact with the C-terminal 94-244 amino acids of RPS3 (C-RPS3). Biochemical analysis of C-RPS3 revealed that it comprises a standalone apurnic-apyrimidinic endonuclease-like domain. We used U2OS cells to show that oxidative stress and UV exposure could enhance the interaction between nuclear RPS3 and RECQL4. Regulation of RECQL4 biochemical activities by RPS3 along with nuclear interaction during UV and oxidative stress may serve to modulate active DNA repair.
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PMID:Ribosomal Protein S3 Negatively Regulates Unwinding Activity of RecQ-like Helicase 4 through Their Physical Interaction. 2815 39


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