title: Interference of mouse mammary tumor virus replication by PTT.119 [p-fluoro-L-phe-m-bis-(2-chloroethyl)amino-L-phe-met ethoxy HCl]--an antitumor agent.
abstract: PTT.119 [p-fluoro-L-Phe-m-bis-(2-chloroethyl)-amino-L-Phe-Met ethoxy HCl] is a new bifunctional alkylating compound that possesses both cytolytic and antiviral activities. Continuous treatment of mouse mammary tumor cells with 15 microM PTT.119 reduced production of the B-type retrovirus murine mammary tumor virus (MuMTV). MuMTV levels in PTT.119-treated cultures were reduced by 31% in the first 24 hours; an additional 24 hours of treatment resulted in a further reduction of 70%. These reductions were significantly greater than could be accounted for by the effects of PTT.119 tumor cell metabolism and viability. Under identical treatment conditions, equimolar concentrations of L-phenylalanine mustard reduced MuMTV production by only 3%. PTT.119 inhibition of MuMTV replication was also apparent when mammary tumor cells were exposed for periods as short as 0.5-4 hours; persistent decreases in virus production were detected even 7 days following tripeptide treatment. Analyses of the polypeptide composition of MuMTV by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that virions from these PTT.119-treated mammary tumor cultures contained significant reductions in the relative level of the nonglycosylated 24,000-dalton (p24) viral polypeptide associated with the nucleoprotein core. Decreases in p24 were observed in MuMTV produced in the presence of the tripeptide and 1-7 days after removal of PTT.119. Examination of the steady-state levels and rates of intracellular MuMTV protein synthesis suggested that PTT.119 interferes with late steps in MuMTV processing and maturation.
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006023:Glycoproteins / Q000032:analysis; D008324:Mammary Tumor Virus, Mouse / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D009588:Nitrogen Mustard Compounds / Q000494:pharmacology* / Q000627:therapeutic use; D012367:RNA, Viral / Q000096:biosynthesis; D012190:Retroviridae / Q000187:drug effects; D012191:Retroviridae Proteins / Q000032:analysis / Q000096:biosynthesis; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000970:Antineoplastic Agents; D006023:Glycoproteins; D009588:Nitrogen Mustard Compounds; D012367:RNA, Viral; D012191:Retroviridae Proteins; C038259:ambamustine