title: Initial testing (stage 1) of the polyamine analog PG11047 by the pediatric preclinical testing program.
abstract: BACKGROUND
  PG11047 is a novel conformationally restricted analog of the natural polyamine, spermine that lowers cellular endogenous polyamine levels and competitively inhibits natural polyamine functions leading to cancer cell growth inhibition. The activity of PG11047 was evaluated against the PPTP's in vitro and in vivo panels.
  
  
  METHODS
  PG11047 was evaluated against the PPTP in vitro panel using 96 hr exposure at concentrations ranging from 10 nM to 100 µM. It was tested against the PPTP in vivo panels at a dose of 100 mg/kg administered by the intraperitoneal route weekly for 6 weeks.
  
  
  RESULTS
  In vitro PG11047 demonstrated a concentration-response pattern consistent with cytostatic activity. The median EC(50) for PG11047 was 71 nM. Cell lines of the Ewing sarcoma panel had a lower median EC(50) value compared to the remaining cell lines in the panel, while cell lines of the neuroblastoma panel had a higher median EC(50) value. In vivo PG11047 induced significant differences in EFS distribution compared to control in 5 of 32 (15.6%) of the evaluable solid tumor xenografts and in 0 of 7 (0%) of the evaluable ALL xenografts. The single case of tumor regression occurred in an ependymoma xenograft.
  
  
  CONCLUSIONS
  Further pediatric development of PG11047 will require better defining a target population and identifying combinations for which there is a tumor-selective cytotoxic effect. The regression observed for an ependymoma xenograft and the exquisite sensitivity of some Ewing sarcoma cell lines to the antiproliferative effects of PG11047 provide leads for further preclinical investigations.
authors.affiliation: Cancer Therapy Evaluation Program, NCI, Bethesda, Maryland 20892, USA. smithm@ctep.nci.nih.gov
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: Smith
authors.forename: John M
authors.initials: JM
authors.lastname: Maris
authors.forename: Richard
authors.initials: R
authors.lastname: Lock
authors.forename: E Anders
authors.initials: EA
authors.lastname: Kolb
authors.forename: Richard
authors.initials: R
authors.lastname: Gorlick
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Keir
authors.forename: Hernan
authors.initials: H
authors.lastname: Carol
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Morton
authors.forename: C Patrick
authors.initials: CP
authors.lastname: Reynolds
authors.forename: Min H
authors.initials: MH
authors.lastname: Kang
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Houghton
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002648:Child; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D009369:Neoplasms / Q000188:drug therapy*; D013096:Spermine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
chemical_list: D013096:Spermine