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1.  Suppression of pancreatic carcinoma growth by activating peroxisome proliferator-activated receptor γ involves angiogenesis inhibition 
AIM: To study the possible actions and mechanisms of peroxisome proliferator-activated receptor γ (PPARγ), a ligand-activated transcription factor, in pancreatic carcinogenesis, especially in angiogenesis.
METHODS: Expressions of PPARγ and retinoid acid receptor (RXRα) were examined by reverse-transcription polymerase chain reaction (RT-PCR) with immunocytochemical staining. Pancreatic carcinoma cells, PANC-1, were treated either with 9-cis-RA, a ligand of RXRα, or with 15-deoxy-Δ12,14 prostaglandin J2 (15d-PGJ2), a ligand of PPARγ, or both. Antiproliferative effect was evaluated by cell viability using methyltetrazolium (MTT) assay. A pancreatic carcinoma xenograft tumor model of nude mice was established by inoculating PANC-1 cells subcutaneously. Rosiglitazone, a specific ligand of PPARγ, was administered via water drinking in experimental group of nude mice. After 75 d, all mice were sacrificed. Expression of proliferating cell nuclear antigen (PCNA) in tumor tissue was examined with immunohistochemical staining. Expression of vascular endothelial growth factor (VEGF) mRNA in PANC-1 cells, which were treated with 15d-PGJ2 or 9-cis-RA at various concentrations or different duration, was detected by semi-quantitative RT-PCR. Effects of Rosiglitazone on changes of microvascular density (MVD) and VEGF expression were investigated in xenograft tumor tissue. Neovasculature was detected with immunohistochemistry staining labeled with anti-IV collagen antibody, and indicated by MVD.
RESULTS: RT-PCR and immunocytochemical staining showed that PPARγ and RXRα were expressed in PANC-1 cells at both transcription level and translation level. MTT assay demonstrated that 15d-PGJ2, 9-cis-RA and their combination inhibited the growth of PANC-1 cells in a dose-dependent manner. 9-cis-RA had a combined inhibiting action with 15d-PGJ2 on the growth of pancreatic carcinoma. In vivo studies revealed that Rosiglitazone significantly suppressed the growth of pancreatic carcinoma as compared to control group (0.48 ± 0.23 cm3 vs 2.488 ± 0.59 cm3, P < 0.05), and the growth inhibition rate was 80.7%. Immunohistochemistry study showed that PCNA was down regulated in Rosiglitazone-treated group compared to the control group. 15d-PGJ2, 9-cis-RA and their combination inhibited the expression of VEGF mRNA in PANC-1 cells in a dose- and time-dependent manner. MVD was decreased more significantly in Rosiglitazone-treated mice (10.67 ± 3.07) than in the control group (31.44 ± 6.06) (P < 0.01). VEGF expression in xenograft tumor tissue was also markedly down-regulated in Rosiglitazone-treated mice.
CONCLUSION: Activation of PPARγ inhibits the growth of pancreatic carcinoma both in vitro and in vivo. Suppression of tumor angiogenesis by down-regulating the expression of VEGF may be one of the mechanisms by which PPARγ activation inhibits the growth of pancreatic carcinoma.
PMCID: PMC2653365  PMID: 19152448
Pancreatic carcinoma; Peroxisome proliferator-activated receptor γ; Angiogenesis; Vascular endothelial growth factor
2.  (E)-2,4,6-Trimethyl-N-(pyridin-2-yl­methyl­idene)aniline 
In the title compound, C15H16N2, has an E conformation about the central N=C bond. The benzene and pyridine rings are almost normal to one another with a dihedral angle of 87.47(8)°. In the crystal, there are no classical hydrogen bonds.
PMCID: PMC3344547  PMID: 22590309
3.  18α-Glycyrrhetinic Acid Down-Regulates Expression of Type I and III Collagen via TGF-Β1/Smad Signaling Pathway in Human and Rat Hepatic Stellate Cells 
Objective: To investigate the effects of 18α-glycyrrhetinic acid (18α-GA) on the expression of type I and III collagen in human and rat hepatic stellate cells (HSC) and to explore the role of TGF-β1/Smad signaling pathway involved.
Methods: Following 18α-GA treatment, the cell viability and cell growth were detected to determine the optimal concentration of 18α-GA. The expressions of TGF-β1/Smad signaling-related genes including type I and III collagen in human and rat HSCs before and after 18α-GA treatment were measured by real time PCR. The expression of related proteins was verified by western blot assay. The phosphorylation level of Smad2 and Smad3 was detected by immunocytochemistry. The DNA binding activities of SP-1, AP-1 and NF-κB were measured by both EMSA and ArrayStar transcription factor activity assay.
Results: 18α-GA could decrease the mRNA and protein expression of Smad3, type I and III collagen, increase the Smad7 expression in human and rat HSCs (P<0.05), and reduce phosphorylation level of Smad3 at 24 h and 48 h after treatment. The DNA binding activities of transcription factors were suppressed by 18α-GA in human and rat HSCs at 24 h, and the activities reduced in a time dependent manner with the lowest activities at 48 h, especially for SP-1.
Conclusion: 18α-GA could inhibit the mRNA and protein expression of type I and III collagen in human and rat HSCs, which may be attributed to down-regulation of Smad3, up-regulation of Smad7, and inhibition of DNA binding activities of SP-1, AP-1 and NF-κB.
PMCID: PMC3399217  PMID: 22811611
18α-glycyrrhetinic acid; hepatic stellate cell; TGF-β1/Smad; transcription factor

Results 1-3 (3)