PT  - JOURNAL ARTICLE
AU  - Chrysoula Leontiou
AU  - Gary P. Watters
AU  - Kathryn L. Gilroy
AU  - Pauline Heslop
AU  - Ian G. Cowell
AU  - Kate Craig
AU  - Robert N. Lightowlers
AU  - Jeremy H. Lakey
AU  - Caroline A. Austin
TI  - Differential Selection of Acridine Resistance Mutations in Human DNA Topoisomerase IIβ Is Dependent on the Acridine Structure
AID  - 10.1124/mol.106.032953
DP  - 2007 Apr 01
TA  - Molecular Pharmacology
PG  - 1006--1014
VI  - 71
IP  - 4
4099  - http://molpharm.aspetjournals.org/content/71/4/1006.short
4100  - http://molpharm.aspetjournals.org/content/71/4/1006.full
SO  - Mol Pharmacol2007 Apr 01; 71
AB  - Type II DNA topoisomerases are targets of acridine drugs. Nine mutations conferring resistance to acridines were obtained by forced molecular evolution, using methyl N-(4′-(9-acridinylamino)-3-methoxy-phenyl) methane sulfonamide (mAMSA), methyl N-(4′-(9-acridinylamino)-2-methoxy-phenyl) carbamate hydrochloride (mAMCA), methyl N-(4′-(9-acridinylamino)-phenyl) carbamate hydrochloride (AMCA), and N-[2-(dimethylamino)ethyl]acridines-4-carboxamide (DACA) as selection agents. Mutations βH514Y, βE522K, βG550R, βA596T, βY606C, βR651C, and βD661N were in the B′ domain, and βG465D and βP732L were not. With AMCA, four mutations were selected (βE522K, βG550R, βA596T, and βD661N). Two mutations were selected with mAMCA (βY606C and βR651C) and two with mAMSA (βG465D and βP732L). It is interesting that there was no overlap between mutation selection with AMCA and mAMSA or mAMCA. AMCA lacks the methoxy substituent present in mAMCA and mAMSA, suggesting that this motif determines the mutations selected. With the fourth acridine DACA, five mutations were selected for resistance (βG465D, βH514Y, βG550R, βA596T, and βD661N). βG465D was selected with both DACA and mAMSA, and βG550R, βA596T, and βD661N were selected with both DACA and AMCA. DACA lacks the anilino motif of the other three drugs but retains the acridine ring motif. The overlap in selection with DACA and mAMSA or AMCA suggests that altered recognition of the acridine moiety may be involved in these mutations. We used restriction fragment length polymorphisms and heteroduplex analysis to demonstrate that some mutations were selected multiple times (βG465D, βE522K, βG550R, βA596T, and βD661N), whereas others were selected only once (βH514Y, βY606C, βR651C, and βP732L). Here, we compare the drug resistance profile of all nine mutations and report the biochemical characterization of three, βG550R, βY606C, and βD661N. The American Society for Pharmacology and Experimental Therapeutics