title: Withaferin A Induces Cell Death Selectively in Androgen-Independent Prostate Cancer Cells but Not in Normal Fibroblast Cells.
abstract: Withaferin A (WA), a major bioactive component of the Indian herb Withania somnifera, induces cell death (apoptosis/necrosis) in multiple types of tumor cells, but the molecular mechanism underlying this cytotoxicity remains elusive. We report here that 2 μM WA induced cell death selectively in androgen-insensitive PC-3 and DU-145 prostate adenocarcinoma cells, whereas its toxicity was less severe in androgen-sensitive LNCaP prostate adenocarcinoma cells and normal human fibroblasts (TIG-1 and KD). WA also killed PC-3 cells in spheroid-forming medium. DNA microarray analysis revealed that WA significantly increased mRNA levels of c-Fos and 11 heat-shock proteins (HSPs) in PC-3 and DU-145, but not in LNCaP and TIG-1. Western analysis revealed increased expression of c-Fos and reduced expression of the anti-apoptotic protein c-FLIP(L). Expression of HSPs such as HSPA6 and Hsp70 was conspicuously elevated; however, because siRNA-mediated depletion of HSF-1, an HSP-inducing transcription factor, reduced PC-3 cell viability, it is likely that these heat-shock genes were involved in protecting against cell death. Moreover, WA induced generation of reactive oxygen species (ROS) in PC-3 and DU-145, but not in normal fibroblasts. Immunocytochemistry and immuno-electron microscopy revealed that WA disrupted the vimentin cytoskeleton, possibly inducing the ROS generation, c-Fos expression and c-FLIP(L) suppression. These observations suggest that multiple events followed by disruption of the vimentin cytoskeleton play pivotal roles in WA-mediated cell death.
authors.affiliation: Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, 565-0871, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Nishikawa
authors.affiliation: Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, 565-0871, Japan; DNA-chip Development Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, 565-0871, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Okuzaki
authors.affiliation: Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, 565-0871, Japan.
authors.forename: Kohshiro
authors.initials: K
authors.lastname: Fukushima
authors.affiliation: Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, 565-0871, Japan.
authors.forename: Satomi
authors.initials: S
authors.lastname: Mukai
authors.affiliation: Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, 565-0871, Japan.
authors.forename: Shouichi
authors.initials: S
authors.lastname: Ohno
authors.affiliation: Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, 565-0871, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ozaki
authors.affiliation: Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, 565-0871, Japan.
authors.forename: Norikazu
authors.initials: N
authors.lastname: Yabuta
authors.affiliation: Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, 565-0871, Japan; DNA-chip Development Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka, 565-0871, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nojima
mesh_terms: D000728:Androgens / Q000378:metabolism*; D001343:Autophagy; D016923:Cell Death / Q000187:drug effects*; D045744:Cell Line, Tumor; D016895:Culture Media, Serum-Free; D019008:Drug Resistance, Neoplasm; D004721:Endoplasmic Reticulum / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000187:drug effects; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D015854:Up-Regulation; D014746:Vimentin / Q000378:metabolism; D054358:Withanolides / Q000494:pharmacology*
chemical_list: D000728:Androgens; D016895:Culture Media, Serum-Free; D016760:Proto-Oncogene Proteins c-fos; D014746:Vimentin; D054358:Withanolides; C009684:withaferin A