title: DNA topoisomerase I--targeted chemotherapy of human colon cancer in xenografts.
abstract: Drug development is needed to improve chemotherapy of patients with locally advanced or metastatic colon carcinoma, who otherwise have an unfavorable prognosis. DNA topoisomerase I, a nuclear enzyme important for solving topological problems arising during DNA replication and for other cellular functions, has been identified as a principal target of a plant alkaloid 20(S)-camptothecin. Significantly increased concentrations of this enzyme, compared to that in normal colonic mucosa, were found in advanced stages of human colon adenocarcinoma and in xenografts of colon cancer carried by immunodeficient mice. Several synthetic analogs of camptothecin, selected by tests with the purified enzyme and tissue-culture screens, were evaluated in the xenograft model. Unlike other anticancer drugs tested, 20(RS)-9-amino-camptothecin (9-AC) induced disease-free remissions. The overall drug toxicity was low and allowed for repeated courses of treatment.
authors.affiliation: Stehlin Foundation for Cancer Research, St. Joseph Hospital, Houston, TX 77002.
authors.forename: B C
authors.initials: BC
authors.lastname: Giovanella
authors.forename: J S
authors.initials: JS
authors.lastname: Stehlin
authors.forename: M E
authors.initials: ME
authors.lastname: Wall
authors.forename: M C
authors.initials: MC
authors.lastname: Wani
authors.forename: A W
authors.initials: AW
authors.lastname: Nicholas
authors.forename: L F
authors.initials: LF
authors.lastname: Liu
authors.forename: R
authors.initials: R
authors.lastname: Silber
authors.forename: M
authors.initials: M
authors.lastname: Potmesil
mesh_terms: D000230:Adenocarcinoma / Q000032:analysis / Q000188:drug therapy* / Q000201:enzymology; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000032:analysis; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000627:therapeutic use* / Q000633:toxicity; D003110:Colonic Neoplasms / Q000032:analysis / Q000188:drug therapy* / Q000201:enzymology; D004264:DNA Topoisomerases, Type I / Q000032:analysis; D004273:DNA, Neoplasm / Q000032:analysis; D015195:Drug Design; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology; D051379:Mice; D008815:Mice, Inbred Strains; D009368:Neoplasm Transplantation; D059004:Topoisomerase I Inhibitors; D014183:Transplantation, Heterologous
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D059004:Topoisomerase I Inhibitors; D004264:DNA Topoisomerases, Type I; D002166:Camptothecin