scholarly journals Mutation of the Murine Bloom's Syndrome Gene Produces Global Genome Destabilization

2006 ◽  
Vol 26 (17) ◽  
pp. 6713-6726 ◽  
Author(s):  
Nicholas Chester ◽  
Holger Babbe ◽  
Jan Pinkas ◽  
Charlene Manning ◽  
Philip Leder
Keyword(s):  
Cell Lines ◽  
Human Cancer ◽  
Genetic Disorder ◽  
Dna Helicase ◽  
Sister Chromatid Exchanges ◽  
Conditional Knockout ◽  
Chromosome Loss ◽  
Bloom's Syndrome ◽  
Bloom’S Syndrome

ABSTRACT Bloom's syndrome (BS) is a genetic disorder characterized cellularly by increases in sister chromatid exchanges (SCEs) and numbers of micronuclei. BS is caused by mutation in the BLM DNA helicase gene and involves a greatly enhanced risk of developing the range of malignancies seen in the general population. With a mouse model for the disease, we set out to determine the relationship between genomic instability and neoplasia. We used a novel two-step analysis to investigate a panel of eight cell lines developed from mammary tumors that appeared in Blm conditional knockout mice. First, the panel of cell lines was examined for instability. High numbers of SCEs were uniformly seen in members of the panel, and several lines produced chromosomal instability (CIN) manifested by high numbers of chromosomal structural aberrations (CAs) and chromosome missegregation events. Second, to see if Blm mutation was responsible for the CIN, time-dependent analysis was conducted on a tumor line harboring a functional floxed Blm allele. The floxed allele was deleted in vitro, and mutant as well as control subclones were cultured for 100 passages. By passage 100, six of nine mutant subclones had acquired high CIN. Nine mutant subclones produced 50-fold more CAs than did nine control subclones. Finally, chromosome loss preceded the appearance of CIN, suggesting that this loss provides a potential mechanism for the induction of instability in mutant subclones. Such aneuploidy or CIN is a universal feature of neoplasia but has an uncertain function in oncogenesis. Our results show that Blm gene mutation produces this instability, strengthening a role for CIN in the development of human cancer.

scholarly journals RECQ-like helicases Sgs1 and BLM regulate R-loop–associated genome instability

2017 ◽  
Vol 216 (12) ◽  
pp. 3991-4005 ◽  
Author(s):  
Emily Yun-Chia Chang ◽  
Carolina A. Novoa ◽  
Maria J. Aristizabal ◽  
Yan Coulombe ◽  
Romulo Segovia ◽  
...  
Keyword(s):  
Genome Instability ◽  
Human Cancer ◽  
Dna Helicase ◽  
Bloom's Syndrome ◽  
Human Cancer Cells ◽  
Bloom’S Syndrome ◽  
Dna Replication And Repair ◽  
Copy Number Changes ◽  
Long Genes

Sgs1, the orthologue of human Bloom’s syndrome helicase BLM, is a yeast DNA helicase functioning in DNA replication and repair. We show that SGS1 loss increases R-loop accumulation and sensitizes cells to transcription–replication collisions. Yeast lacking SGS1 accumulate R-loops and γ-H2A at sites of Sgs1 binding, replication pausing regions, and long genes. The mutation signature of sgs1Δ reveals copy number changes flanked by repetitive regions with high R-loop–forming potential. Analysis of BLM in Bloom’s syndrome fibroblasts or by depletion of BLM from human cancer cells confirms a role for Sgs1/BLM in suppressing R-loop–associated genome instability across species. In support of a potential direct effect, BLM is found physically proximal to DNA:RNA hybrids in human cells, and can efficiently unwind R-loops in vitro. Together, our data describe a conserved role for Sgs1/BLM in R-loop suppression and support an increasingly broad view of DNA repair and replication fork stabilizing proteins as modulators of R-loop–mediated genome instability.

scholarly journals The Bloom's Syndrome Helicase Is Critical for Development and Function of the αβ T-Cell Lineage

2007 ◽  
Vol 27 (5) ◽  
pp. 1947-1959 ◽  
Author(s):  
Holger Babbe ◽  
Nicholas Chester ◽  
Philip Leder ◽  
Boris Reizis
Keyword(s):  
T Cell ◽  
Genetic Disorder ◽  
Cell Lineage ◽  
Unknown Origin ◽  
Cell Receptor ◽  
Dna Helicase ◽  
Vital Role ◽  
Bloom's Syndrome ◽  
Bloom’S Syndrome ◽  
And Function

ABSTRACT Bloom's syndrome is a genetic disorder characterized by increased incidence of cancer and an immunodeficiency of unknown origin. The BLM gene mutated in Bloom's syndrome encodes a DNA helicase involved in the maintenance of genomic integrity. To explore the role of BLM in the immune system, we ablated murine Blm in the T-cell lineage. In the absence of Blm, thymocytes were severely reduced in numbers and displayed a developmental block at the β-selection checkpoint that was partially p53 dependent. Blm-deficient thymocytes rearranged their T-cell receptor (TCR) β genes normally yet failed to survive and proliferate in response to pre-TCR signaling. Furthermore, peripheral T cells were reduced in numbers, manifested defective homeostatic and TCR-induced proliferation, and produced extensive chromosomal damage. Finally, CD4+ and CD8+ T-cell responses were impaired upon antigen challenge. Thus, by ensuring genomic stability, Blm serves a vital role for development, maintenance, and function of T lymphocytes, suggesting a basis for the immune deficiency in Bloom's syndrome.

Synthesis and Cytotoxicity Assessment of Novel 7-O- and 14-O-Derivatives of Glaucocalyxin A

2020 ◽  
Vol 20 (10) ◽  
pp. 1241-1249
Author(s):  
Hong-Chuan Liu ◽  
Li-Ming Qiao ◽  
Wei Zheng ◽  
Zhao-Bao Xiang ◽  
Hai-Sheng Chen ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Cell Lines ◽  
Cancer Cell ◽  
Human Cancer ◽  
Folk Medicine ◽  
A549 Cells ◽  
Cancer Cell Lines ◽  
Human Cancer Cell Lines ◽  
Derivatives Of

Background: Rabdosia japonica has been historically used in China as a popular folk medicine for the treatment of cancer, hepatitis, and gastricism. Glaucocalyxin A (GLA), an ent-kaurene diterpene isolated from Rabdosia japonica, is one of the main active ingredients showing potent inhibitory effects against several types of tumor cells. To the best of our knowledge, studies regarding the structural modification and Structure- Activity Relations (SAR) of this compound have not yet been reported. Objective: The aim of this study was to discover more potent derivatives of GLA and investigate their SAR and cytotoxicity mechanisms. Methods: Novel 7-O- and 14-O-derivatives of GLA were synthesized by condensation of acids or acyl chloride. The anti-tumor activities of these derivatives against various human cancer cell lines were evaluated in vitro by MTT assays. Apoptosis assays of compound 17 (7,14-diacylation product) were performed on A549 and HL-60 cells by flow cytometry and TUNNEL. The acute toxicity of this compound was tested on mice, at the dose of 300mg per kg body weight. Results: Seventeen novel 7-O- and 14-O-derivatives of GLA (1-17) were synthesized. These compounds showed potent cytotoxicity against the tested cancer cell lines, and almost all of them were found to be more cytotoxic than GLA and oridonin. Of the synthesized derivatives, compound 17 presented the greatest cytotoxicity, with IC50 values of 0.26μM and 1.10μM in HL-60 and CCRF-CEM cells, respectively. Furthermore, this compound induced weak apoptosis of A549 cells but showed great potential in stimulating the apoptosis of HL- 60 cells. Acute toxicity assays indicated that compound 17 is relatively safer. Conclusion: The results reported herein indicate that the synthesized GLA derivatives exhibited greater cytotoxicity against leukemia cells than against other types of tumors. In particular, 7,14-diacylation product of GLA was found to be an effective anti-tumor agent. However, the cytotoxicity mechanism of this product in A549 cells is expected to be different than that in other tumor cell lines. Further research is needed to confirm this hypothesis.

scholarly journals Discovery of New Pyrazolopyridine, Furopyridine, and Pyridine Derivatives as CDK2 Inhibitors: Design, Synthesis, Docking Studies, and Anti-Proliferative Activity

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3923
Author(s):  
Adel A.-H. Abdel-Rahman ◽  
Amira K. F. Shaban ◽  
Ibrahim F. Nassar ◽  
Dina S. EL-Kady ◽  
Nasser S. M. Ismail ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cancer Cell ◽  
Human Cancer ◽  
Cancer Cell Lines ◽  
Human Cancer Cell ◽  
Molecular Docking Study ◽  
Human Cancer Cell Lines ◽  
Hct 116 ◽  
Mcf 7

New pyridine, pyrazoloyridine, and furopyridine derivatives substituted with naphthyl and thienyl moieties were designed and synthesized starting from 6-(naphthalen-2-yl)-2-oxo-4-(thiophen-2-yl)-1,2-dihydropyridine-3-carbonitrile (1). The chloro, methoxy, cholroacetoxy, imidazolyl, azide, and arylamino derivatives were prepared to obtain the pyridine-−C2 functionalized derivatives. The derived pyrazolpyridine-N-glycosides were synthesized via heterocyclization of the C2-thioxopyridine derivative followed by glycosylation using glucose and galactose. The furopyridine derivative 14 and the tricyclic pyrido[3′,2′:4,5]furo[3,2-d]pyrimidine 15 were prepared via heterocyclization of the ester derivative followed by a reaction with formamide. The newly synthesized compounds were evaluated for their ability to in vitro inhibit the CDK2 enzyme. In addition, the cytotoxicity of the compounds was tested against four different human cancer cell lines (HCT-116, MCF-7, HepG2, and A549). The CDK2/cyclin A2 enzyme inhibitory results revealed that pyridone 1, 2-chloro-6-(naphthalen-2-yl)-4-(thiophen-2-yl)nicotinonitrile (4), 6-(naphthalen-2-yl)-4-(thiophen-2-yl)-1H-pyrazolo[3,4-b]pyridin-3-amine (8), S-(3-cyano-6-(naphthaen-2-yl)-4-(thiophen-2-yl)pyridin-2-yl) 2-chloroethanethioate (11), and ethyl 3-amino-6-(naphthalen-2-yl)-4-(thiophen-2-yl)furo[2,3-b]pyridine-2-carboxylate (14) are among the most active inhibitors with IC50 values of 0.57, 0.24, 0.65, 0.50, and 0.93 µM, respectively, compared to roscovitine (IC50 0.394 μM). Most compounds showed significant inhibition on different human cancer cell lines (HCT-116, MCF-7, HepG2, and A549) with IC50 ranges of 31.3–49.0, 19.3–55.5, 22.7–44.8, and 36.8–70.7 μM, respectively compared to doxorubicin (IC50 40.0, 64.8, 24.7 and 58.1 µM, respectively). Furthermore, a molecular docking study suggests that most of the target compounds have a similar binding mode as a reference compound in the active site of the CDK2 enzyme. The structural requirements controlling the CDK2 inhibitory activity were determined through the generation of a statistically significant 2D-QSAR model.

scholarly journals Synthesis of New Simplified and Racemic Hemiasterlin Derivatives with Extremely High Cytotoxicity

2018 ◽  
Vol 13 (12) ◽  
pp. 1934578X1801301
Author(s):  
Pham The Chinh ◽  
Đang Thi Tuyet Anh ◽  
Duong Huong Quynh ◽  
Le Nhat Thuy Giang ◽  
Nguyen Ha Thanh ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Cell Lines ◽  
Human Cancer ◽  
Microtubule Depolymerization ◽  
Antimitotic Agent ◽  
Human Cancer Cell Lines ◽  
Weak Activity ◽  
High Cytotoxicity ◽  
Chemistry Community

Hemiasterlin is a potent antimitotic agent acting through inhibition of microtubule depolymerization. For this reason, the synthesis of new hemiasterlin derivatives has attracted a lot of interest in the organic chemistry community recently. In this paper, the synthesis and evaluation of the cytotoxicity of new simplified and racemic hemiasterlin derivatives were reported. All of the synthesized analogues were evaluated in vitro for cytotoxic activity against four human cell lines (KB, Hep-G2, LU and MCF7). Most of these analogues possess a strong cytotoxic activity on two human cancer cell lines (KB and Hep-G2) and very weak activity on LU and MCF7 cell lines.

scholarly journals SPIONs/3D SiSBA-16 based Multifunctional Nanoformulation for target specific cisplatin release in colon and cervical cancer cell lines

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
B. Rabindran Jermy ◽  
Munther Alomari ◽  
Vijaya Ravinayagam ◽  
Sarah Ameen Almofty ◽  
Sultan Akhtar ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Magnetic Resonance ◽  
Cell Lines ◽  
Cancer Cell ◽  
Human Cancer ◽  
Cancer Cell Lines ◽  
Dapi Staining ◽  
Tem Analysis ◽  
Human Cancer Cell Lines

Abstract Multifunctional nanomaterials can be used for dual applications: drug delivery as well as in bioimaging. In current study, we investigated potential use of silica based supports; 3D cage type SiSBA-16 (S-16), monodispersed hydrophilic spherical silica (HYPS) and mesocellular foam (MSU-F) for cisplatin (Cp) delivery. To obtain magnetic resonance characteristics, 10 wt% iron oxide was loaded through enforced adsorption technique. For pH stimuli responsive release of Cp, 10 wt%SPIONs/S-16 was functionalized with 3-(Aminopropyl)triethoxysilane (A) and poly acrylic acid (PAA) termed as 10 wt%SPIONs/S-16-A-Cp and 10 wt%SPIONs/S-16-APAA-Cp. By TEM analysis, the average diameter of the SPIONs was found to range between 10–60 nm. VSM analysis showed saturation magnetization over S-16, HYPS and MSU-F were in the following order: 10 wt%SPIONs/HYPS (4.08 emug−1) > 10 wt%SPIONs /S-16 (2.39 emug−1) > 10 wt%SPIONs/MSU-F (0.23 emug−1). Cp release study using dialysis membrane in PBS solution over 10 wt%SPIONs/S-16 nanoformulations showed highest cumulative release (65%) than 10 wt%SPIONs/MSU-F-A-Cp (63%), 10 wt%SPIONs/HYPS-A-Cp (58%), and Cp-F127/S-16 (53%), respectively. 10 wt%SPIONs/S-16-A-Cp and 10 wt%SPIONs/S-16-APAA-Cp were evaluated for in vitro target anticancer efficiency in human cancer cell lines (colon cancer (HCT 116), cervical cancer (HeLa)) and normal cells (Human embryonic kidney cells (HEK293) using MTT and DAPI staining. 10 wt%SPIONs/S-16-A-Cp treated Hela and HCT116 cancerous cell lines showed significant control of cell growth, apoptotic activity and less cytotoxic effect as compared to Cp and 10 wt%SPIONs/S-16. Target specific Cp release in the cells shows that 10 wt%SPIONs/S-16-A-Cp can be easily upgraded for magnetic resonance imaging capability.

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