Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:5.99.1.2 (topoisomerase)
 9,166 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A mechanism of action study was performed with 14 novel DNA binding agents characterized structurally as 2-(arylmethylamino)-1,3-propanediols (AMAPs). Correlations between 8226 myeloma cell colony formation and DNA damage were performed using soft agar colony-forming assays and alkaline elution filter techniques respectively. The frequency of double-stranded breaks (DSBs), single-stranded breaks (SSBs) and DNA-protein cross-links were compared with cell growth inhibitory potency. Highly potent AMAPs in the colony formation assays included 91U86, an N-methyl-5-benzo(c)carbazole derivative, 773U82, a 3-substituted fluoranthene derivative, and crisnatol (770U82), the 6-substituted chrysene derivative. There was a high frequency of SSBs and DSBs with many analogues, but only SSBs occurred in a concentration-dependent fashion. Using regression analysis, the degree of single-strand damage correlated with cytotoxic potency for the AMAPs, with an R-value of 0.57 (P = 0.04). By gel electrophoresis assays, three clinically tested AMAPs, crisnatol BW 770U82, BW 502U83 and BW 773U82, were shown to inhibit the decatenation of pBR 322 DNA by purified topoisomerase-II (TOPO-II) enzymes. These results suggest that while some active AMAPs, such as crisnatol (BW 770U82), BW 502U83 and BW 773U82, inhibit TOPO-II enzymes, leading to protein-associated SSBs, other mechanisms, which do not involve DNA strand damage, must also contribute to the cytotoxic effects of this class of antitumor compounds. Intercalation has been well documented for these drugs and this may explain some of the growth inhibitory activity of the AMAPs.
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PMID:Correlation of cytotoxicity and protein-associated DNA strand breaks for 2-(arylmethylamino)-1,3-propanediols. 980 65

Amonafide, a naphthalimide derivative, although selected for exploratory clinical trials for its potent anticancer activity, has long been challenged by its unpredictable side effects. In the present study, a novel amonafide analogue, 2-(2-dimethylamino)-6-thia-2-aza-benzo-[def]-chrysene-1,3-diones (R16) was synthesized by substituting 5'-NH(2) of the naphthyl with a heterocyclic group to amonafide, with additional introduction of a thiol group. In a panel of various human tumor cell lines, R16 was more cytotoxic than its parent compound amonafide. It was also effective against multidrug-resistant cells. Importantly, the i.p. administration of R16 inhibited tumor growth in mice implanted with S-180 sarcoma and H(22) hepatoma. The molecular and cellular machinery studies showed that the R16 functions as a topoisomerase II (topo II) poison via binding to the ATPase domain of human topo IIalpha. The superior cytotoxicity of R16 to amonafide was ascribed to its potent effects on trapping topo II-DNA cleavage complexes. Moreover, using a topo II catalytic inhibitor aclarubicin, ataxia-telangiectasia-mutated (ATM)/ATM- and Rad3-related (ATR) kinase inhibitor caffeine and topo II-deficient HL-60/MX2 cells, we further showed that R16-triggered DNA double-strand breaks, tumor cell cycle arrest, and apoptosis were in a topo II-dependent manner. Taken together, R16 stood out by its improved anticancer activity, appreciable anti-multidrug resistance activities, and well-defined topo II poisoning mechanisms, as comparable with the parent compound amonafide. All these collectively promise the potential value of R16 as an anticancer drug candidate, which deserves further development.
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PMID:R16, a novel amonafide analogue, induces apoptosis and G2-M arrest via poisoning topoisomerase II. 1730 47