scholarly journals DNA sequence selectivity of human topoisomerase I-mediated DNA cleavage induced by camptothecin

2009 ◽  
Vol 18 (6) ◽  
pp. 1326-1331
Author(s):  
Chandanamali Punchihewa ◽  
Megan Carver ◽  
Danzhou Yang
Keyword(s):  
Dna Sequence ◽  
Dna Cleavage ◽  
Topoisomerase I ◽  
Sequence Selectivity

DNA sequence selectivity of cisplatin analogues in intact human cells

1998 ◽  
Vol 110 (1-2) ◽  
pp. 27-37 ◽  
Author(s):  
Vincent Murray ◽  
Joanne Whittaker ◽  
W.David McFadyen
Keyword(s):  
Dna Sequence ◽  
Human Cells ◽  
Cisplatin Analogues ◽  
Sequence Selectivity

scholarly journals Antisense transcripts enhanced by camptothecin at divergent CpG-island promoters associated with bursts of topoisomerase I-DNA cleavage complex and R-loop formation

2013 ◽  
Vol 41 (22) ◽  
pp. 10110-10123 ◽  
Author(s):  
Jessica Marinello ◽  
Giovanni Chillemi ◽  
Susana Bueno ◽  
Stefano G. Manzo ◽  
Giovanni Capranico
Keyword(s):  
Dna Cleavage ◽  
Topoisomerase I ◽  
Cpg Island ◽  
Loop Formation ◽  
Antisense Transcripts ◽  
Cleavage Complex

Molecular Beacon Enables Combination of Highly Processive and Highly Sensitive Rolling Circle Amplification Readouts for Detection of DNA-Modifying Enzymes

Nano LIFE ◽  
2015 ◽  
Vol 05 (02) ◽  
pp. 1541002 ◽  
Author(s):  
Emil L. Kristoffersen ◽  
Maria Gonzalez ◽  
Magnus Stougaard ◽  
Cinzia Tesauro
Keyword(s):  
Real Time ◽  
Dna Cleavage ◽  
Topoisomerase I ◽  
Drug Response ◽  
Molecular Beacon ◽  
Rolling Circle Amplification ◽  
Dna Topoisomerase ◽  
Rolling Circle ◽  
Topoisomerase Ib ◽  
Highly Sensitive

Here we present an optimized readout format for detection of the circularized products from a DNA-based sensor for measurement of DNA-modifying enzymes including DNA Topoisomerase I. The basic design of the DNA-sensor relies on the use of a substrate that can be circularized by the activity of DNA-modifying enzymes like type IB Topoisomerases and subsequently amplified by a rolling circle amplification (RCA) mechanism. The RCA process can be followed in real-time by the addition of a molecular beacon with a fluorophore/quencher pair. Upon hybridization to the amplified product, the fluorophore/quencher pair is separated, giving rise to a fluorescent signal, measurable in pseudo real-time using a qPCR machine or in a fluorimeter. The RCA products in complex with the molecular beacon can subsequently be moved to microscopic slides and analyzed in a fluorescence microscope. We describe the proof of the principle of this molecular beacon-based method combining the qPCR readout format with the standard Rolling circle Enhanced Enzymatic Assay previously reported. Although the qPCR setup is less sensitive, it allows easy, fast, and high-throughput measurement of enzyme activities. Human Topoisomerase IB (TopIB) is a well-known target for the clinically used anticancer drugs of the camptothecin family. The cytotoxic effect of camptothecins correlates directly with the intracellular TopIB activity affecting reversibly the Topoisomerase/DNA cleavage complexes. Therefore, we envisioned that the presented method may find use for the prediction of cellular drug response and for drug screening to discover novel molecules that specifically inhibit TopIB or other DNA-modifying enzymes.

scholarly journals DNA Topoisomerase I Inhibitory Activity of Quinochalcone C-glycosides from the Florets of Carthamus tinctorius

2017 ◽  
Vol 12 (11) ◽  
pp. 1934578X1701201
Author(s):  
Shi-Jun Yue ◽  
Wen-Xiao Wang ◽  
Cheng Qu ◽  
Lan-Ting Xin ◽  
Yu-Ping Tang ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
Dna Cleavage ◽  
Topoisomerase I ◽  
Docking Study ◽  
Carthamus Tinctorius ◽  
In Vitro Cytotoxicity ◽  
Molecular Docking Study ◽  
Dna Topoisomerase ◽  
Cleavage Complex

The DNA topoisomerase (Topo) I inhibitory activity of six quinochalcone C-glycosides (QCGs) isolated from the florets of Carthamus tinctorius were evaluated in vitro. Among them, anhydrosafflor yellow B (AHSYB, 4) and carthorquinoside B (6) could inhibit DNA Topo I at concentrations as low as 100 μM. Molecular docking study revealed that both of them have the capacity to stabilize Topo I-DNA cleavage complex in silico interacting with the essential binding sites, such as Arg364, Thr718 and TGP11. Besides, both compounds 4 and 6 exhibited no antitumor activity by in vitro cytotoxicity assays.

Sign in / Sign up

Export Citation Format

Share Document