title: Inhibition by retinoic acid of murine retrovirus-induced cellular transformation and tumor formation.
abstract: The effect of all-trans-retinoic acid (RA) on cellular transformation and on tumorigenicity of retrovirally transformed cells was investigated. RA treatment of NRK and NIH/3T3 cells transformed by BALB/c murine sarcoma virus (MuSV), Kirsten murine sarcoma virus (K-MuSV), and simian sarcoma virus resulted in a significant reduction in anchorage-dependent growth of only K-MuSV-transformed NRK cells. A 62% reduction in cell number was observed at 10(-5) M RA. In contrast, anchorage-independent growth induced by each of the viruses tested was suppressed by RA. Balb/cMSV3T3 cells showed the greatest level of sensitivity with a significant reduction in anchorage-independent growth occurring at 10(-9) M RA. The level of cytoplasmic retinoic acid-binding protein (CRABP) was determined in both parent and transformed cell lines. CRABP was present at a high level in all 3T3 cell types but was absent in all NRK cell lines. For testing the antineoplastic activity of RA in vivo, Balb/cMSV3T3 cells were injected intradermally into nude mice. Subsequent treatment of the tumor sites of these animals by topical application of RA resulted in a significant reduction in both tumor incidence and tumor size, confirming the in vitro results. Analysis of the level of v-onc mRNA revealed that inhibition of retroviral transformation by RA was not due to a decrease in transcription of the v-onc genes.
authors.forename: N A
authors.initials: NA
authors.lastname: Giese
authors.forename: K E
authors.initials: KE
authors.lastname: Neary
authors.forename: N
authors.initials: N
authors.lastname: Levine
authors.forename: T J
authors.initials: TJ
authors.lastname: Lindell
authors.forename: J J
authors.initials: JJ
authors.lastname: Duffy
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000032:analysis; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002472:Cell Transformation, Viral / Q000187:drug effects*; D051379:Mice; D008819:Mice, Nude; D009857:Oncogenes / Q000187:drug effects; D012333:RNA, Messenger / Q000032:analysis; D012367:RNA, Viral / Q000032:analysis; D018168:Receptors, Retinoic Acid; D012842:Sarcoma Virus, Woolly Monkey / Q000235:genetics; D009053:Sarcoma Viruses, Murine / Q000235:genetics; D012878:Skin Neoplasms / Q000517:prevention & control*; D014158:Transcription, Genetic / Q000187:drug effects; D014212:Tretinoin / Q000494:pharmacology* / Q000627:therapeutic use; D014412:Tumor Virus Infections / Q000517:prevention & control*
chemical_list: D002352:Carrier Proteins; D012333:RNA, Messenger; D012367:RNA, Viral; D018168:Receptors, Retinoic Acid; D014212:Tretinoin