title: Checkpoint kinase 1 regulates diallyl trisulfide-induced mitotic arrest in human prostate cancer cells.
abstract: We have shown previously that diallyl trisulfide (DATS), a constituent of processed garlic, inhibits proliferation of PC-3 and DU145 human prostate cancer cells by causing G(2)-M phase cell cycle arrest in association with inhibition of cyclin-dependent kinase 1 activity and hyperphosphorylation of Cdc25C at Ser(216). Here, we report that DATS-treated PC-3 and DU145 cells are also arrested in mitosis as judged by microscopy following staining with anti-alpha-tubulin antibody and 4',6-diamidino-2-phenylindole and flow cytometric analysis of Ser(10) phosphorylation of histone H3. The DATS treatment caused activation of checkpoint kinase 1 and checkpoint kinase 2, which are intermediaries of DNA damage checkpoints and implicated in Ser(216) phosphorylation of Cdc25C. The diallyl trisulfide-induced Ser(216) phosphorylation of Cdc25C as well as mitotic arrest were significantly attenuated by knockdown of check-point kinase 1 protein in both PC-3 and DU145 cells. On the other hand, depletion of checkpoint kinase 2 protein did not have any appreciable effect on G(2) or M phase arrest or Cdc25C phosphorylation caused by diallyl trisulfide. The lack of a role of checkpoint kinase 2 in diallyl trisulfide-induced phosphorylation of Cdc25C or G(2)-M phase cell cycle arrest was confirmed using HCT-15 cells stably transfected with phosphorylation-deficient mutant (T68A mutant) of checkpoint kinase 2. In conclusion, the results of the present study suggest existence of a checkpoint kinase 1-dependent mechanism for diallyl trisulfide-induced mitotic arrest in human prostate cancer cells.
authors.affiliation: Department of Pharmacology and University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Herman-Antosiewicz
authors.forename: Shivendra V
authors.initials: SV
authors.lastname: Singh
mesh_terms: D000498:Allyl Compounds / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects* / Q000502:physiology; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D006801:Humans; D008297:Male; D008938:Mitosis / Q000187:drug effects* / Q000502:physiology; D011471:Prostatic Neoplasms; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D013440:Sulfides / Q000494:pharmacology*; D014162:Transfection
chemical_list: D000498:Allyl Compounds; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D013440:Sulfides; C042577:diallyl trisulfide; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1