OBJECTIVE: The objective of the study was to evaluate the expression and functional activity of Peroxisome proliferator-activated receptor (PPAR) gamma in pituitary adenomas from 14 consecutive acromegalic patients and to establish its role in apoptosis. SUBJECTS AND METHODS: Fourteen consecutive acromegalic patients were enrolled in the study. Wistar-Furth rats were used for in vivo studies. Expression of PPARgamma was evaluated by RT-PCR and Western blot. Apoptosis and cell cycle were assessed by FACS analysis. The effects of PPARgamma ligands on transcriptional regulation of GH gene were evaluated by RT-PCR and electromobility shift assay. RESULTS: PPARgamma was expressed in all human GH-secreting adenoma (GH-oma), in normal pituitary tissue samples (39+/-24% and 78+/-5% of immunostained nuclei respectively; P<0.0002; ANOVA), and in rat GH-secreting (GH3) cells. A PPRE-containing reporter plasmid transfected into GH3 cells was activated by ciglitazone or rosiglitazone (TZDs), indicating that PPARgamma was functionally active. Treatment of GH3 cells with TZDs increased apoptosis in a dose-dependent manner (P=0.0003) and arrested cell proliferation, reducing the number of cells in the S-phase (P<0.0001 vs untreated cells). TZDs increased the expression of TRAIL, leaving unaffected that of p53 and Bax. TZDs reduced GH concentrations in the culture media from 43.7+/-5.4 ng/ml to 2.1+/-0.3 ng/ml (P<0.0001) and in cell extracts (P<0.004). PPARgamma-RXRalpha heterodimers bound to GH promoter, inhibiting its activity and reducing GH mRNA levels (1.8 x 10(6) vs 5.7 x 10(6) transcripts respectively vs untreated cells; P<0.002). Subcutaneous GH-oma developed in rats injected with GH3 cells; tumor growth increased in placebo-treated rats and to a lesser extent in TZDs-treated animals (24.1+/-2.0 g, and 14.8+/-4.2 g respectively, P<0.03). Serum GH concentrations were lower in TZDs-treated rats than in controls (871+/-67 ng/ml vs 1.309+/-238 ng/ml; P<0.05). CONCLUSIONS: The results of this study indicate that PPARgamma controls GH transcription and secretion as well as apoptosis and growth of GH-oma; thus, TZDs have the potential of a useful tool in the complex therapeutic management of acromegalic patients.
OBJECTIVE: The objective of the study was to evaluate the expression and functional activity of Peroxisome proliferator-activated receptor (PPAR) gamma in pituitary adenomas from 14 consecutive acromegalicpatients and to establish its role in apoptosis. SUBJECTS AND METHODS: Fourteen consecutive acromegalicpatients were enrolled in the study. Wistar-Furth rats were used for in vivo studies. Expression of PPARgamma was evaluated by RT-PCR and Western blot. Apoptosis and cell cycle were assessed by FACS analysis. The effects of PPARgamma ligands on transcriptional regulation of GH gene were evaluated by RT-PCR and electromobility shift assay. RESULTS:PPARgamma was expressed in all humanGH-secreting adenoma (GH-oma), in normal pituitary tissue samples (39+/-24% and 78+/-5% of immunostained nuclei respectively; P<0.0002; ANOVA), and in rat GH-secreting (GH3) cells. A PPRE-containing reporter plasmid transfected into GH3 cells was activated by ciglitazone or rosiglitazone (TZDs), indicating that PPARgamma was functionally active. Treatment of GH3 cells with TZDs increased apoptosis in a dose-dependent manner (P=0.0003) and arrested cell proliferation, reducing the number of cells in the S-phase (P<0.0001 vs untreated cells). TZDs increased the expression of TRAIL, leaving unaffected that of p53 and Bax. TZDs reduced GH concentrations in the culture media from 43.7+/-5.4 ng/ml to 2.1+/-0.3 ng/ml (P<0.0001) and in cell extracts (P<0.004). PPARgamma-RXRalpha heterodimers bound to GH promoter, inhibiting its activity and reducing GH mRNA levels (1.8 x 10(6) vs 5.7 x 10(6) transcripts respectively vs untreated cells; P<0.002). Subcutaneous GH-oma developed in rats injected with GH3 cells; tumor growth increased in placebo-treated rats and to a lesser extent in TZDs-treated animals (24.1+/-2.0 g, and 14.8+/-4.2 g respectively, P<0.03). Serum GH concentrations were lower in TZDs-treated rats than in controls (871+/-67 ng/ml vs 1.309+/-238 ng/ml; P<0.05). CONCLUSIONS: The results of this study indicate that PPARgamma controls GH transcription and secretion as well as apoptosis and growth of GH-oma; thus, TZDs have the potential of a useful tool in the complex therapeutic management of acromegalicpatients.
Authors: F Bogazzi; D Russo; M T Locci; B Chifenti; F Ultimieri; F Raggi; P Viacava; D Cecchetti; C Cosci; C Sardella; G Acerbi; M Gasperi; E Martino Journal: J Endocrinol Invest Date: 2005-11 Impact factor: 4.256
Authors: F Bogazzi; G Rossi; M Lombardi; F Raggi; C Urbani; C Sardella; C Cosci; E Martino Journal: J Endocrinol Invest Date: 2010-07-29 Impact factor: 4.256
Authors: Baowen Du; William P Cawthorn; Alison Su; Casey R Doucette; Yao Yao; Nahid Hemati; Sarah Kampert; Colin McCoin; David T Broome; Clifford J Rosen; Gongshe Yang; Ormond A MacDougald Journal: J Biol Chem Date: 2012-12-17 Impact factor: 5.157
Authors: I Cellai; G Petrangolini; M Tortoreto; G Pratesi; P Luciani; C Deledda; S Benvenuti; C Ricordati; S Gelmini; E Ceni; A Galli; M Balzi; P Faraoni; M Serio; A Peri Journal: Br J Cancer Date: 2010-01-12 Impact factor: 7.640