title: Benzyl isothiocyanate-induced DNA damage causes G2/M cell cycle arrest and apoptosis in human pancreatic cancer cells.
abstract: Benzyl isothiocyanate (BITC) has been shown to inhibit chemically induced pancreatic cancer in experimental animals. However, the mechanism responsible for the anticancer effects of BITC is not clearly understood. In this study, we tested whether BITC treatment would affect the growth of Capan-2 human pancreatic cancer cells. BITC (10 micromol/L) treatment caused marked phosphorylation of H2A.x (2.6-fold) and permanent damage to Capan-2 cells. BITC-mediated G2/M arrest was associated with up-regulation of cyclin dependent kinase inhibitor p21(Waf1/Cip1) and the activation of checkpoint kinase 2, whereas the expressions of other G2/M regulatory proteins, including CyclinB1, Cdc2, and cell division cycle 25C (Cdc25C), were down-regulated by 19, 51, and 70%, respectively, compared with control. These changes resulted in a 55% inhibition of Cdc2 kinase activity. In addition, the decline in the expression of Cdc25C was completely blocked when the cells were treated with lactacystin (proteasome inhibitor) prior to BITC treatment. However, G2/M arrest and apoptosis induced by BITC were partially blocked by pretreatment of cells with lactacystin. Taken together, the results of this study suggest the involvement of multiple signaling pathways targeted by BITC in mediating G2/M cell cycle arrest and apoptosis in Capan-2 cells and warrant further investigation.
authors.affiliation: Department of Pharmacology and University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
authors.forename: Ruifen
authors.initials: R
authors.lastname: Zhang
authors.forename: Sivakumar
authors.initials: S
authors.lastname: Loganathan
authors.forename: Ian
authors.initials: I
authors.lastname: Humphreys
authors.forename: Sanjay K
authors.initials: SK
authors.lastname: Srivastava
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019926:Cyclin B / Q000378:metabolism; D056744:Cyclin B1; D004249:DNA Damage; D016195:G2 Phase / Q000187:drug effects*; D017879:Isothiocyanates / Q000494:pharmacology*; D008297:Male; D051379:Mice; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000473:pathology
chemical_list: C534699:CCNB1 protein, human; C534700:Ccnb1 protein, mouse; D019926:Cyclin B; D056744:Cyclin B1; D017879:Isothiocyanates; C067713:lactacystin; C031403:benzyl isothiocyanate; D016203:CDC2 Protein Kinase; D000111:Acetylcysteine