title: Selective cytotoxicity of benzyl isothiocyanate in the proliferating fibroblastoid cells.
abstract: In the present study, experiments using presynchronization culture cells demonstrated that benzyl ITC (BITC), previously isolated from a tropical papaya fruit extract, induced the cytotoxic effect preferentially in the proliferating human colon CCD-18Co cells to the quiescent ones. Quiescent CCD-18Co cells were virtually unaffected by BITC and marginal cytotoxicity was observed at 15 microM. We observed that BITC dramatically induced the p53 phosphorylation and stabilization only in the quiescent (G(0)/G(1) phase-arrested) cells, but not significantly in the proliferating human colon CCD-18Co cells when compared with quiescent ones. We also observed ataxia telangiectasia-mutated (ATM) phosphorylation in the quiescent cells. The BITC-induced p53 phosphorylation was counteracted by caffeine treatment, implying the involvement of an ATM/ataxia telangiectasia and Rad3-related kinase signaling pathway. Moreover, downregulation of p53 by a siRNA resulted in the enhancement of susceptibility to undergo apoptosis by BITC. We also showed here that depletion of p53 abrogated G(0)/G(1) arrest accompanied by the declined expression of p21(waf1/cip1) and p27(kip1) in CCD-18Co cells. In conclusion, we identified p53 as a potential negative regulator of the apoptosis induction by BITC in the normal colon CCD-18Co cells through the inhibition of cell-cycle progression at the G(0)/G(1) phase.
authors.affiliation: Laboratory of Biochemistry, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Miyoshi
authors.forename: Koji
authors.initials: K
authors.lastname: Uchida
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Osawa
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Nakamura
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D029441:Carica / Q000737:chemistry*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D003106:Colon / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D016193:G1 Phase / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D015151:Immunoblotting; D020287:In Situ Nick-End Labeling; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D017879:Isothiocyanates / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016196:S Phase / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: C493956:CDKN1A protein, human; C436291:CDKN1B protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D047908:Intracellular Signaling Peptides and Proteins; D017879:Isothiocyanates; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D050760:Cyclin-Dependent Kinase Inhibitor p27; C031403:benzyl isothiocyanate