title: Agelastatin A: a novel inhibitor of osteopontin-mediated adhesion, invasion, and colony formation.
abstract: Effective inhibitors of osteopontin (OPN)-mediated neoplastic transformation and metastasis are still lacking. (-)-Agelastatin A is a naturally occurring oroidin alkaloid with powerful antitumor effects that, in many cases, are superior to cisplatin in vitro. In this regard, past comparative assaying of the two agents against a range of human tumor cell lines has revealed that typically (-)-agelastatin A is 1.5 to 16 times more potent than cisplatin at inhibiting cell growth, its effects being most pronounced against human bladder, skin, colon, and breast carcinomas. In this study, we have investigated the effects of (-)-agelastatin A on OPN-mediated malignant transformation using mammary epithelial cell lines. Treatment with (-)-agelastatin A inhibited OPN protein expression and enhanced expression of the cellular OPN inhibitor, Tcf-4. (-)-Agelastatin A treatment also reduced beta-catenin protein expression and reduced anchorage-independent growth, adhesion, and invasion in R37 OPN pBK-CMV and C9 cell lines. Similar effects were observed in MDA-MB-231 and MDA-MB-435s human breast cancer cell lines exposed to (-)-agelastatin A. Suppression of Tcf-4 by RNA interference (short interfering RNA) induced malignant/invasive transformation in parental benign Rama 37 cells; significantly, these events were reversed by treatment with (-)-agelastatin A. Our study reveals, for the very first time, that (-)-agelastatin A down-regulates beta-catenin expression while simultaneously up-regulating Tcf-4 and that these combined effects cause repression of OPN and inhibition of OPN-mediated malignant cell invasion, adhesion, and colony formation in vitro. We have also shown that (-)-agelastatin A inhibits cancer cell proliferation by causing cells to accumulate in the G(2) phase of cell cycle.
authors.affiliation: Centre for Cancer Research and Cell Biology, Queen's University Belfast, Northern Ireland, UK.
authors.forename: Charlene K
authors.initials: CK
authors.lastname: Mason
authors.forename: Suzanne
authors.initials: S
authors.lastname: McFarlane
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Johnston
authors.forename: Paul
authors.initials: P
authors.lastname: Crowe
authors.forename: Pauline J
authors.initials: PJ
authors.lastname: Erwin
authors.forename: Mathias M
authors.initials: MM
authors.lastname: Domostoj
authors.forename: F Charles
authors.initials: FC
authors.lastname: Campbell
authors.forename: Soraya
authors.initials: S
authors.lastname: Manaviazar
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Hale
authors.forename: Mohamed
authors.initials: M
authors.lastname: El-Tanani
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects* / Q000502:physiology; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D006801:Humans; D009361:Neoplasm Invasiveness / Q000517:prevention & control*; D009362:Neoplasm Metastasis / Q000517:prevention & control; D053495:Osteopontin / Q000235:genetics / Q000502:physiology*; D023303:Oxazolidinones / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D034622:RNA Interference
chemical_list: D000470:Alkaloids; D023303:Oxazolidinones; C464968:agelastatin A; D053495:Osteopontin