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Depurination of dA and dG Induced by 2-bromopropane at the Physiological Condition
( Pritam Thapa ),( Jyoti Sherchan ),( Radha Karki ),( Tae Cheon Jeong ),( Eung Seok Lee ) 한국응용약물학회 2007 Biomolecules & Therapeutics(구 응용약물학회지) Vol.15 No.4
Depurination, the release of purine bases from nucleosides by hydrolysis of the N-glycosidic bond, gives rise to alterations of the cell genome. Although, cells have evolved mechanisms to repair these lesions, unrepaired apurinic sites have been shown to have two biological consequences: lethality and base substitution errors. 2-Bromopropane (2-BP) is used as an intermediate in the synthesis of pharmaceuticals, dyes, and other organics. In addition, 2-BP has been used as a cleaning solvent in electronics industry. But, 2-BP was found to cause reproductive and hematopoietic disorders in local workers exposed to it. We observed massive depurination after incubation of 2`-deoxyadenosine (dA) and 2`-deoxyguanosine (dG) with the excess amount 2-BP at the physiological condition (pH 7.4, 37℃), which were analyzed by HPLC and LC-MS/MS. In addition, time and dose response relationship of depurination in dA and dG induced by 2-BP at the physiological condition were investigated.
( Pritam Thapa ),( Yurngdong Jahng ),( Pil Hoon Park ),( Jun Goo Jee ),( Youngjoo Kwon ),( Eung Seok Lee ) 영남대학교 약품개발연구소 2014 영남대학교 약품개발연구소 연구업적집 Vol.24 No.0
Designed and synthesized twenty-four 2,4-diaryl benzofuro[3,2-b]pyridine derivatives were evaluated for topoisomerase I and II inhibitory activities as well as cytotoxicities against several human cancer cell lines. Various aryl groups such as phenyl, 2- or 3- furyl, 2- or 3-thienyl, and 2-pyridyl were substituted at 2- or 4- position of central pyridine. Compounds 8, 12, 13, and 14, with 2-furyl either at 2- or 4- position of central pyridine showed the significant topoisomerase II inhibitory activity at 100 μM.
( Pritam Thapa ),( Radha Karki ),( Min Ho Yun ),( Tara Man Kadayat ),( Eun Young Lee ),( Han Byeol Kwon ),( Young Hwa Na ),( Won Jea Cho ),( Nam Doo Kim ),( Byeong Seon Jeong ),( Young Joo Kwon ),( Eu 영남대학교 약품개발연구소 2012 영남대학교 약품개발연구소 연구업적집 Vol.22 No.0
We have designed and synthesized a series of 2,4,6-triaryl pyridine derivatives containing chlorophenyl and phenolic moeity at 2- and 4- position of the central pyridine, respectively, resulting in a total of 42 compounds. They were evaluated for topoisomerase I and II inhibitory activities as well as cytotoxicities against several human cancer cell lines. Most compounds showed better topoisomerase II inhibitory activity compared to topoisomerase I inhibitory activity. Compounds 19, 20, 26-28, and 47-50 especially showed stronger topo II inhibitory activity than etoposide. ⓒ 2012 Elsevier Masson SAS. All rights reserve
Thapa, Pritam,Jahng, Yurngdong,Park, Pil-Hoon,Jee, Jun-Goo,Kwon, Youngjoo,Lee, Eung-Seok Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.10
Designed and synthesized twenty-four 2,4-diaryl benzofuro[3,2-b]pyridine derivatives were evaluated for topoisomerase I and II inhibitory activities as well as cytotoxicities against several human cancer cell lines. Various aryl groups such as phenyl, 2- or 3- furyl, 2- or 3-thienyl, and 2-pyridyl were substituted at 2- or 4- position of central pyridine. Compounds 8, 12, 13, and 14, with 2-furyl either at 2- or 4- position of central pyridine showed the significant topoisomerase II inhibitory activity at 100 ${\mu}M$.
( Pritam Thapa ),( Kyu Yeon Jun ),( Tara Man Kadayat ),( Chanmi Park ),( Zhi Zheng ),( Til Bahadur Thapa Magar ),( Ganesh Bist ),( Aarajana Shrestha ),( Younghwa Na ),( Youngjoo Kwon ),( Eung Seok Lee 영남대학교 약품개발연구소 2016 영남대학교 약품개발연구소 연구업적집 Vol.26 No.-
To develop novel selective topoisomerase II inhibitors, we designed and synthesized a series of conforma-tionally constrained hydroxylated 4-phenyl-2-aryl chromenopyridines and evaluated their to poi so-merase inhibitory activity and cytotoxicity against three human cancer cell lines (DU145, HCn5, and T47D) and a normal cell line (MCF10A). All of the prepared compounds displayed stronger or similar topoisomerase II inhibitory activity as well as cytotoxicity against three human cancer cell lines com-pared to etoposide. Compounds 10., 109, 11., 11f, 11g, 12., 12f, and 12g especially showed stronger topoisornerase II inhibitory activity as compared to etoposide at both 100 μM and 20 μM. A structure-ac-tivity relationship study revealed that hydroxyphenyl moiety at 4-position of pyridine and ortho-hydrox-yphenyl or thienyl moiety at 2-position of pyridine has an important role in displaying selective topoisomerase II inhibition. The compound 12b with para-hydroxyphenyl and meta-hydroxyphenyl at 4- and 2-position of pyridine. respectively, showed the most significant cytotoxicity against all three can-cer cell lines, whereas less cytotoxicity to a normal cell line as compared to adriamycin.
Identification of a N7-guanine adduct of 1-bromopropane in calf thymus DNA by mass spectrometry
Pritam Thapa,김은경,Mahesh Raj Nepal,정기선,강미정,노금한,이상규,정혜광,이준호,정태천,이응석 대한독성 유전단백체 학회 2016 Molecular & cellular toxicology Vol.12 No.1
As a replacement for chlorofluorocarbons that cause ozone depletion, 1-bromopropane has been widely used in work place. In the present study, the formation of N7-guanine adduct in DNA by 1-bromopropane was evaluated in vitro to elucidate the possible mechanism of its toxic action. N7-Propyl guanine was chemically synthesized and structurally characterized by NMR, UV, HPLC, and liquid chromatographyelectrospray ionization mass spectrometry (LC- ESI MS) for using as a reference standard. An incubation of 2ʹ-deoxyguanosine with 1-bromopropane produced N7-propyl adduct, which was identified by UV, HPLC and ESI-MS. In addition, N7-guanine adduct was also identified from the incorporation of calf thymus DNA with 1-bromopropane at the physiological condition by LC-ESI MS. Furthermore, the production of adduct was proportional to the amounts of 1-bromopropane used. These results indicated that the molecular mechanism underlying toxic effects of 1-bromopropane would be associated with the adduct formation on DNA at least in part.