title: Cytotoxicity of 15-deoxy-Δ(12,14)-prostaglandin J(2) through PPARγ-independent pathway and the involvement of the JNK and Akt pathway in renal cell carcinoma.
abstract: BACKGROUND
  Agonists of peroxisome proliferator-activated receptor gamma (PPARγ) have been examined as chemopreventive and chemotherapeutic agents. The aim was to investigate the cytotoxicity and action mechanisms of 15-deoxy-Δ(12,14)-prostaglandin J(2) (15d-PGJ(2)), one of endogenous ligands for PPARγ, in terms of PPARγ-dependency and the mitogen-activated protein kinase (MAPK) and Akt pathway in three human renal cell carcinoma (RCC)-derived cell lines.
  
  
  METHODS
  786-O, Caki-2 and ACHN cells were used as human RCC-derived cell lines. Cell viability and caspase-3 activity was detected by fluorescent reagents, and chromatin-condensation was observed with a brightfield fluorescent microscope after staining cells with Hoechst33342. The expression levels of proteins were detected by Western blot analysis.
  
  
  RESULTS
  15d-PGJ(2) showed cytotoxicity in dose-dependent manner. 15d-PGJ(2) induced chromatin-condensation and elevated caspase-3 activity, and the cell viability was restored by co-treatment with a pan-caspase inhibitor, Z-VAD-FMK, indicating the involvement of caspase-dependent apoptosis. The cytotoxicity was not impaired by a PPARγ inhibitor, GW9662, suggesting that 15d-PGJ(2) exerted the cytotoxicity in a PPARγ-independent manner. Some antioxidants rescued cells from cell death induced by 15d-PGJ(2), but some did not, suggesting that reactive oxygen species (ROS) did not contribute to the apoptosis. 15d-PGJ(2) also increased the expression levels of phospho-c-Jun N terminal kinase (JNK) in Caki-2 cells, and decreased those of phospho-Akt in 786-O cells, indicating that the JNK MAPK and the Akt pathways participated in the anticancer effects of 15d-PGJ(2) in some cell lines.
  
  
  CONCLUSIONS
  15d-PGJ(2) exerted cytotoxic effects accompanying caspase-dependent apoptosis, and this effect was elicited in a PPARγ-independent manner in three cell lines. In addition, the JNK MAPK and Akt pathway was involved in the cytotoxicity of 15d-PGJ(2) to some extent in some cell line. Therefore, our study showed the 15d-PGJ(2) to potentially be an interesting approach for RCC treatment.
authors.affiliation: Department of Clinical Pharmacy, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, 11-68 Koshien-kyuban-cho, Nishinomiya, Hyogo 663-8179, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Fujita
authors.forename: Chiaki
authors.initials: C
authors.lastname: Tohji
authors.forename: Yoko
authors.initials: Y
authors.lastname: Honda
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakamura
authors.forename: Tatsurou
authors.initials: T
authors.lastname: Yagami
authors.forename: Motohiro
authors.initials: M
authors.lastname: Yamamori
authors.forename: Noboru
authors.initials: N
authors.lastname: Okamura
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D015153:Blotting, Western; D002292:Carcinoma, Renal Cell / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D005470:Fluorometry; D006801:Humans; D007680:Kidney Neoplasms / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D048670:MAP Kinase Kinase 4 / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D047495:PPAR gamma / Q000502:physiology*; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000633:toxicity; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: C097240:15-deoxy-delta(12,14)-prostaglandin J2; D000975:Antioxidants; D047495:PPAR gamma; D017382:Reactive Oxygen Species; D007770:L-Lactate Dehydrogenase; D051057:Proto-Oncogene Proteins c-akt; D048670:MAP Kinase Kinase 4; D015230:Prostaglandin D2