title: Induction of cell-cycle arrest and apoptosis by a novel retinobenzoic-acid derivative, TAC-101, in human pancreatic-cancer cells.
abstract: In this study, we investigated the effect of a novel retinobenzoic acid, 4-[3,5-bis (trimethylsilyl) benzamido] benzoic acid (TAC-101), on the growth of 4 human pancreatic-cancer cell lines; BxPC-3, MIAPaCa-2, CFPAC-1 and AsPC-1. TAC-101 significantly inhibited the proliferation of BxPC-3 and MIAPaCa-2 cells in a time- and concentration-dependent manner, but not the proliferation of AsPC-1 cells. Furthermore, the anti-proliferative effects of TAC-101 on BxPC-3 and MIAPaCa-2 cells were stronger than those of all-trans retinoic acid. Flow-cytometric analyses indicated that treatment of BxPC-3 with TAC-101 strongly induces cell-cycle arrest at the G1 phase. The cell-cycle arrest induced by TAC-101 was accompanied by reduction of retinoblastoma-gene product (RB) phosphorylation and an increase of 2 cyclin-dependent kinase (CDK) inhibitors, p21(WAF1/Cip1) (p21) and p27Kip1 (p27). TAC-101 also caused a decrease in cyclin A and thymidylate synthase, which are E2F-regulated gene products. No changes were observed in the expression of cyclin D1, cyclin E on CDK2. In addition, Hoechst staining, gel electrophoresis and flow-cytometric analysis indicated that a marked reduction in the number of BxPC-3 cells with TAC-101 was related to the induction of apoptosis. Our results suggest that TAC-101 inhibits the growth of certain pancreatic-cancer cells by means of G1-phase cell-cycle arrest resulting from the reduction of RB phosphorylation and the up-regulation of p21 and p27 as well as the induction of apoptosis. TAC-101 may therefore be a useful agent for new therapeutic strategies focusing on inhibition of pancreatic-cancer-cell proliferation.
authors.affiliation: Department of Surgery and Surgical Basic Science, Kyoto University, Japan. kofuji@kuhp.kyoto-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Fujimoto
authors.forename: R
authors.initials: R
authors.lastname: Hosotani
authors.forename: R
authors.initials: R
authors.lastname: Doi
authors.forename: M
authors.initials: M
authors.lastname: Wada
authors.forename: J U
authors.initials: JU
authors.lastname: Lee
authors.forename: T
authors.initials: T
authors.lastname: Koshiba
authors.forename: Y
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: S
authors.initials: S
authors.lastname: Tsuji
authors.forename: S
authors.initials: S
authors.lastname: Nakajima
authors.forename: M
authors.initials: M
authors.lastname: Imamura
mesh_terms: D000970:Antineoplastic Agents / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects*; D001565:Benzoates / Q000633:toxicity*; D002453:Cell Cycle / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects; D053938:DNA Fragmentation; D004305:Dose-Response Relationship, Drug; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D007700:Kinetics; D010190:Pancreatic Neoplasms; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000235:genetics; D016160:Retinoblastoma Protein / Q000378:metabolism; D000072482:Retinoic Acid Receptor alpha; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014212:Tretinoin / Q000633:toxicity*; D014297:Trimethylsilyl Compounds / Q000633:toxicity*; D014407:Tumor Cells, Cultured; D051028:bcl-2-Associated X Protein
chemical_list: D000970:Antineoplastic Agents; D001565:Benzoates; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C000607071:RARA protein, human; D018168:Receptors, Retinoic Acid; D016160:Retinoblastoma Protein; D000072482:Retinoic Acid Receptor alpha; C112689:TAC 101; D014297:Trimethylsilyl Compounds; D051028:bcl-2-Associated X Protein; D014212:Tretinoin