title: Laminin-1-derived scrambled peptide AG73T disaggregates laminin-1-induced ovarian cancer cell spheroids and improves the efficacy of cisplatin.
abstract: We found previously that the laminin-1-derived synthetic peptide AG73 (LQVQLSIR) promoted ovarian cancer cell metastasis in vivo. We have now studied the role of this metastasis-promoting peptide in vitro using TAC3 ovarian cancer cells, which display anchorage-independent growth and form multicellular spheroids. Our goal is to better understand how this peptide can regulate metastasis in vivo. We found that the exogenous addition of either laminin-1 or peptide AG73 stimulated the formation and growth of the spheroids. Western blot analysis indicated that laminin-1 enhanced the expression of integrin beta1, and that AG73 peptide enhanced expression of syndecan-1 and downstream effectors, including mitogen-activated protein kinase (MAPK) and extracellular signal-related kinase (ERK), and also phosphatidylinositol (PI)-3 kinase/AKT activity signaling. The soluble peptide AG73T, which is a scramble peptide of AG73, was able to disaggregate the laminin-1-induced spheroids. Furthermore, the disaggregated cells were twice as sensitive to cisplatin as the intact spheroids. The AG73T peptide in the presence of laminin-1 suppressed expression of integrin beta1 and its downstream effectors, including MAPK/ERK and PI3/AKT activity signaling. The MEK inhibitor U0126 reduced TAC3 cell growth more effectively in the presence of both laminin-1 and AG73T than in the presence of laminin-1 alone. Inhibition of the PI3-K cascade with LY294002 was also more effective in the presence of laminin-1 and AG73T. The increased sensitivity to cisplatin in the presence of AG73T may be due to the greater bioavailability of the drug to the free-floating cells over the spheroids. These findings suggest a novel function of AG73T in ovarian cancer and help to define mechanisms important in ovarian cancer spheroid formation and spread.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medical Science, University of Fukui, Matuoka, Eiheiji-cho, Yoshida-gun, Fukui-ken 910-1103, Japan. yyoshida@u-fukui.ac.jp
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Kurokawa
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nishikawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Orisa
authors.forename: Hynda K
authors.initials: HK
authors.lastname: Kleinman
authors.forename: Fumikazu
authors.initials: F
authors.lastname: Kotsuji
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D002449:Cell Aggregation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004357:Drug Synergism; D005260:Female; D006801:Humans; D007797:Laminin / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000494:pharmacology*; D010051:Ovarian Neoplasms / Q000473:pathology*; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000187:drug effects; D018874:Spheroids, Cellular / Q000187:drug effects* / Q000473:pathology; D016896:Treatment Outcome; D014407:Tumor Cells, Cultured
chemical_list: C528977:AG73T peptide; D000970:Antineoplastic Agents; D007797:Laminin; D010446:Peptide Fragments; C121346:laminin 1; D002945:Cisplatin