title: New quinoxaline 1,4-di-N-oxides. Part 1: Hypoxia-selective cytotoxins and anticancer agents derived from quinoxaline 1,4-di-N-oxides.
abstract: Hypoxic cells which are common feature of solid tumors are resistant to both anticancer drugs and radiation therapy. Thus, the identification of drugs with the selective toxicity toward hypoxic cells is an important target in anticancer chemotherapy. Tirapazamine has been shown to be an efficient and selective cytotoxin after bioreductive activation in hypoxic cells which is thought to be due to the presence of the 1,4-di-N-oxide. A new series of quinoxaline 1,4-di-N-oxides and fused quinoxaline di-N-oxides were synthesized and evaluated for hypoxic-cytotoxic activity on EAC cell line. Compound 10a was the most potent cytotoxin IC(50) 0.9 microg/mL, potency 75 microg/mL, and was approximately 15 times more selective cytotoxin (HCR>111) than 3-aminoquinoxaline-2-carbonitrile which has been used as a standard (HCR>7.5). Compounds 4 and 3a,b were more selective than the standard. In addition, antitumor activity against Hepg2 (liver) and U251 (brain) human cell lines was evaluated, compounds 9c and 8a were the most active against Hepg2 with IC(50) values 1.9 and 2.9 microg/mL, respectively, however, all the tested compounds were nontoxic against U251 cell line.
authors.affiliation: Pharmaceutical Chemistry Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
authors.forename: Kamelia M
authors.initials: KM
authors.lastname: Amin
authors.forename: Magda M F
authors.initials: MM
authors.lastname: Ismail
authors.forename: Eman
authors.initials: E
authors.lastname: Noaman
authors.forename: Dalia H
authors.initials: DH
authors.lastname: Soliman
authors.forename: Yousry A
authors.initials: YA
authors.lastname: Ammar
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D015687:Cell Hypoxia / Q000187:drug effects; D045744:Cell Line, Tumor; D003603:Cytotoxins / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D066298:In Vitro Techniques; D015394:Molecular Structure; D010087:Oxides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011810:Quinoxalines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D003603:Cytotoxins; D010087:Oxides; D011810:Quinoxalines