prostaglandin-d2 and Urinary-Bladder-Neoplasms

Although PPARgamma antagonists have shown considerable pre-clinical efficacy, recent studies suggest PPARgamma ligands induce PPARgamma-independent effects. There is a need to better define such effects to permit rational utilization of these agents.. We have studied the effects of a range of endogenous and synthetic PPARgamma ligands on proliferation, growth arrest (FACS analysis) and apoptosis (caspase-3/7 activation and DNA fragmentation) in multiple prostate carcinoma cell lines (DU145, PC-3 and LNCaP) and in a series of cell lines modelling metastatic transitional cell carcinoma of the bladder (TSU-Pr1, TSU-Pr1-B1 and TSU-Pr1-B2).. 15-deoxy-prostaglandin J2 (15dPGJ2), troglitazone (TGZ) and to a lesser extent ciglitazone exhibited inhibitory effects on cell number; the selective PPARgamma antagonist GW9662 did not reverse these effects. Rosiglitazone and pioglitazone had no effect on proliferation. In addition, TGZ induced G0/G1 growth arrest whilst 15dPGJ2 induced apoptosis.. Troglitazone and 15dPGJ2 inhibit growth of prostate and bladder carcinoma cell lines through different mechanisms and the effects of both agents are PPARgamma-independent.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma; Carcinoma, Transitional Cell; Caspase 3; Caspase 7; Caspases; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Chromans; DNA Fragmentation; Humans; Ligands; Male; PPAR gamma; Prostaglandin D2; Prostatic Neoplasms; RNA, Messenger; Thiazolidinediones; Troglitazone; Urinary Bladder Neoplasms

Cyclopentenone-prostaglandin derivatives, including the peroxisome-proliferator activated receptor gamma (PPARgamma) ligand 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2), inhibit tumor cell growth in vitro and in vivo. As 15d-PGJ2 was found to stimulate the expression of vascular endothelial growth factor (VEGF) in endothelial cells, we investigated whether 15d-PGJ2 induces this angiogenic factor in the human androgen-independent PC 3 prostate and the 5637 urinary bladder carcinoma cell line. In PC 3 cells, 15d-PGJ2 caused a dose-dependent increase in VEGF mRNA expression, as determined by RT-PCR. Stimulation started after 6 h, and after 72 h, VEGF mRNA expression reached a maximum of 3.3+/-0.3 U, 4.4+/-0.3 U and 6.1+/-0.1 U with 1, 5 and 10 microM 15d-PGJ2, respectively. Between 12-72 h, VEGF protein production was stimulated by up to 2-fold with 5 and 10 microM 15d-PGJ2 as assessed by ELISA in PC 3 cell-conditioned medium. In 5637 cells, 15d-PGJ2 did not alter VEGF mRNA expression for up to 72 h. Thereafter, VEGF mRNA expression was transiently increased from 2.3+/-0.8 U in control cells to 4.6+/-0.5 U in 1 microM and 5.9+/-0.6 U in 5 microM 15d-PGJ2-treated cells. VEGF protein production was only moderately stimulated (1.7-fold). 10 microM 15d-PGJ2 had no effect on VEGF mRNA expression in 5637 cells, but effectively reduced viability in both cell lines. 15d-PGJ2 also increased PPARgamma mRNA expression in both cell lines. While in PC 3 cells, stimulation of PPARgamma mRNA expression occurred after 72 h, in 5637 cells, a transient stimulation took place after 6 h (4-fold). We demonstrated that 15d-PGJ2 induces VEGF in PC 3 and 5637 cancer cells. This might be important if PG-analogues are considered as antitumor agents.

Topics: Cell Survival; Endothelial Growth Factors; Humans; Immunologic Factors; Intercellular Signaling Peptides and Proteins; Ligands; Lymphokines; Male; Prostaglandin D2; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Transcription Factors; Tumor Cells, Cultured; Urinary Bladder Neoplasms; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a member of the nuclear receptor superfamily of ligand-activated transcription factors and is expressed in several types of tissue. Although PPARgamma reportedly is expressed in normal urothelium, its function is unknown. We examined the expression of PPARgamma in normal urothelium and bladder cancer in an attempt to assess its functional role. Immunohistochemical staining revealed normal urothelium to express PPARgamma uniformly. All low-grade carcinomas were positive either diffusely or focally, whereas staining was primarily focal or absent in high-grade carcinomas. A nonneoplastic urothelial cell line (1T-1), a low-grade (RT4) carcinoma cell line, and two high-grade (T24 and 253J) carcinoma cell lines in culture expressed PPARgamma mRNA and protein. Luciferase assay indicated that PPARgamma was functional. PPARgamma ligands (15-deoxy-Delta(12,14)-prostaglandin J(2), troglitazone and pioglitazone) suppressed the growth of nonneoplastic and neoplastic urothelial cells in a dose-dependent manner. However, neoplastic cells were more resistant than were nonneoplastic cells. Failure to express PPARgamma or ineffective transcriptional activity may be some of the mechanisms responsible for resistance to the inhibitory action of PPARgamma ligands.

Topics: Aged; Blotting, Western; Cell Division; Cell Line; Chromans; Dose-Response Relationship, Drug; Humans; Immunologic Factors; Ligands; Male; Pioglitazone; Prostaglandin D2; Receptors, Cytoplasmic and Nuclear; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Thiazoles; Thiazolidinediones; Transcription Factors; Transcription, Genetic; Transfection; Troglitazone; Tumor Cells, Cultured; Urinary Bladder Neoplasms; Urothelium