title: Norcantharidin induces apoptosis in human prostate cancer cells through both intrinsic and extrinsic pathways.
abstract: BACKGROUND
  Norcantharidin, a modified pure compound from blister beetles, was previously demonstrated to induce apoptosis of cancer cells. This study investigated its anti-cancer activity in prostate cancer cells and the mechanisms involved.
  
  
  METHODS
  Two human prostate cancer cell lines, 22Rv1 and Du145, were treated with norcantharidin at concentrations ranging from 3 to 30μg/ml. Cytotoxic effect of norcantharidin was determined by use of the 3-(4,5-dimethylthiazol-yl)-diphenyl tetrazoliumbromide (MTT) assay. The effects of apoptosis were evaluated by cell death assay, Caspase-3, -8, -9 activity and cytochrome c release. The apoptotic related protein expressions (Bcl-2 family and inhibitor of apoptosis proteins) were determined using western blotting.
  
  
  RESULTS
  An MTT assay revealed that norcantharidin induced cytotoxicity against both prostate cancer cells in dose- and time-dependent manners. Treatment with norcantharidin at 3μg/ml or higher significantly increased oligonucleosomal formation with concomitant appearance of PARP cleavage, implicating the induction of apoptosis. Norcantharidin intrinsically elevated cytosolic cytochrome c levels and activated caspase-3, -8, and -9. Extrinsically, it upregulated the expression of not only the death receptors Fas and DR5 in 22Rv1 cells, but also of RIP and TRADD adaptor proteins in Du145 cells. Mechanistically, norcantharidin increased ratios of pro-/anti-apoptotic proteins and decreased expression of IAP family member proteins, including cIAP1 and survivin, regardless of the distinct status of androgen receptor expression in both cells.
  
  
  CONCLUSIONS
  Norcantharidin exhibited cytotoxicity against 22Rv1 and Du145 prostate cancer cells by inducing both intrinsic and extrinsic apoptotic pathways and could thus potentially be a remedy for prostate cancer.
authors.affiliation: Department of Medical Research, Show Chwan Memorial Hospital, Changhua, Taiwan, ROC. Electronic address: peyyuh2900@gmail.com.
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Yang
authors.affiliation: Tissue Culture Center, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA. Electronic address: hu2095@yahoo.com.
authors.forename: Dan-Ning
authors.initials: DN
authors.lastname: Hu
authors.affiliation: Department of Medical Research, E-DA Hospital, Kaohsiung, Taiwan, ROC. Electronic address: danyhkao@gmail.com.
authors.forename: Ying-Hsien
authors.initials: YH
authors.lastname: Kao
authors.affiliation: Department of Family Medicine, Changhua Christian Hospital, Changhua, Taiwan, ROC; School of Medicine, Chung Shan Medical University, Taichung, Taiwan, ROC; School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC. Electronic address: licypy01@gmail.com.
authors.forename: I-Ching
authors.initials: IC
authors.lastname: Lin
authors.affiliation: Division of Urology, Department of Surgery, Show-Chwan Memorial Hospital, Changhua, Taiwan, ROC. Electronic address: yuan117@gmail.com.
authors.forename: Chih-Yuan
authors.initials: CY
authors.lastname: Chou
authors.affiliation: School of Pharmacy, College of Pharmacy, China Medical University, Taichung, Taiwan, ROC. Electronic address: yachwu@mail.cmu.edu.tw.
authors.forename: Yang-Chang
authors.initials: YC
authors.lastname: Wu
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D053199:TNF Receptor-Associated Death Domain Protein / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D019253:Proto-Oncogene Proteins c-bcl-2; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D053199:TNF Receptor-Associated Death Domain Protein; C505639:TNFRSF10B protein, human; D051028:bcl-2-Associated X Protein; D019014:fas Receptor; C069741:norcantharidin; D045304:Cytochromes c; D020169:Caspases
keywords: Apoptosis; Bcl-2 family; Inhibitor of apoptosis (IAP); Norcantharidin; Prostate cancer