Disruption of PPARgamma signaling results in mouse prostatic intraepithelial neoplasia involving active autophagy

Peroxisome proliferator-activated receptor-gamma (PPARgamma) regulates the interface between cellular lipid metabolism, redox status and organelle differentiation. Conditional prostatic epithelial knockout of PPARgamma in mice resulted in focal hyperplasia which developed into mouse prostatic intraepithelial neoplasia (mPIN). The grade of PIN became more severe with time. Electron microscopy (EM) showed accumulated secondary lysosomes containing cellular organelles and debris suggestive of autophagy. Consistent with this analysis the autophagy marker LC-3 was found to be upregulated in areas of PIN in PPARgamma KO tissues. We selectively knocked down PPARgamma2 isoform in wild-type mouse prostatic epithelial cells and examined the consequences of this in a tissue recombination model. Histopathologically grafted tissues resembled the conditional PPARgamma KO mouse prostates. EM studies of PPARgamma- and PPARgamma2-deficient epithelial cells in vitro were suggestive of autophagy, consistent with the prostatic tissue analysis. This was confirmed by examining expression of beclin-1 and LC-3. Gene expression profiling in PPARgamma-/gamma2-deficient cells indicated a major dysregulation of cell cycle control and metabolic signaling networks related to peroxisomal and lysosomal maturation, lipid oxidation and degradation. The putative autophagic phenotypes of PPARgamma-deficient cells could be rescued by re-expression of either gamma1 or gamma2 isoform. We conclude that disruption of PPARgamma signaling results in autophagy and oxidative stress during mPIN pathogenesis.

A 13-week subchronic oral toxicity study of L-serine in rats

A subchronic oral toxicity study was conducted to evaluate the safety of L-serine in Sprague-Dawley rats. The test article was administered once daily by gavage in male and female rats at dose levels of 0, 500, 1500, and 3000 mg/kg body weight/day for 13 weeks. Daily clinical signs, body weight, and food consumption were not affected by ingestion of the test article. There were no treatment-related adverse effects on urinalysis, hematology, serum biochemistry, organ weights, gross and histopathological examination. It was concluded that the no-observed-effect level (NOEL) for L-serine was 3000 mg/kg bw/day for both genders.

Identification of urinary biomarkers to distinguish tumor bearing and control rats in the methylnitrosourea (MNU) – induced model of mammary carcinogenesis: use of label-free, comparative, ultra-high resolution nano-LC mass spectrometry

Abstract #1109

In the MNU induced model of mammary cancer, rats given a single dose of MNU (75 mg/kg BW), via the jugular vein, at 50 days of age develop multiple ER+ mammary cancers. These cancers appear similar to highly differentiated ER+ human breast cancers, and have been shown to be sensitive to many of the same chemotherapeutic agents that are effective in women. When a female rat developed its first palpable cancer, it was placed in a metabolic cage and urine collected overnight on dry ice. The urine from these rats were compared to those obtained from control rats. Using a new sample preparation protocol, peptides were prepared from the urines of control (n = 4 individual animals) and rats bearing induced mammary tumors (n = 4). The peptide pools were analyzed using nano-LC-LTQ-FT-MS. The 8 LC-MS analyses were aligned and the integrated accurate mass signals were quantified using Rosetta ElucidatorTM software. The ion currents from 4430 peptides (charge state > +2) were analyzed between the two groups using ANOVA. Two hundred and twenty nine peptides were found to be significantly different (P< 0.01) between the two groups, with clear distinction between the urines from control and experimental animals being observed using hierarchical clustering and principal component analysis. The protein identifications that were significantly increased in the tumor-bearing urines were confirmed by targeted tandem mass spectrometry. Further studies relating the altered expression of these peptides to differences in tumor size, the effects of therapeutic agents, etc will also be presented.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1109.

Chromatin configurations in the ferret germinal vesicle that reflect developmental competence for in vitro maturation

In several mammalian species, the configuration of germinal vesicle (GV) chromatin correlates with the developmental competence of oocytes. Yet, no study has been published on the configuration of GV chromatin in ferret, nor is it known whether a specific configuration predicts meiotic competence in this species, in spite of the potential importance of ferret cloning to the study of human disease and to species conservation efforts. Here, we report on an analysis of the chromatin configuration in ferret GV oocytes and on how they correlate with meiotic development. Three distinct configurations were identified based on the degree of chromatin condensation: (1) fibrillar chromatin (FC), featuring strands of intertwined chromatin occupying most of the visible GV region; (2) intermediate condensed chromatin (ICC), characterized by dense, irregular chromatin masses throughout the GV; and (3) condensed chromatin (CC), which is highly compact and centered around the nucleolus. We also found that chromatin configuration was related to the extent of association with cumulus cells in cumulus-oocyte complexes; CC-configured oocytes were most often surrounded by a compact cumulus layer and also a compact corona but FC-configured oocytes were associated with neither. In addition, increasing chromatin condensation corresponded to an increase in oocyte diameter. Finally, following in vitro culture, significantly more CC-configured oocytes underwent maturation to meiotic metaphase II than did FC- or ICC-configured oocytes. We conclude that, in ferret, chromatin condensation is related to the sequential achievement of meiotic competencies during oocyte growth and differentiation, and thus can be used as a predictor of competence.

Chromosome 11 genomic changes in parathyroid adenoma and hyperplasia: array CGH, FISH, and tissue microarrays

We have used a combination of gene expression profiling, array comparative genomic hybridization (aCGH), fluorescent in situ hybridization (FISH) and tissue microarrays (TMAs) to investigate chromosome 11 genetic changes in subsets of benign parathyroid tumors. Integration of gene expression profiling and aCGH was done using differential gene locus mapping analysis. We have identified three distinct relatively common chromosome 11 genomic changes in various subsets of parathyroid tumors. The simplest and least common of these genomic changes involves translocation of the CCND1 gene with subsequent strong CCND1 expression. This genetic change is essentially limited to parathyroid adenomas (8%), although expression of CCND1 without translocation is common in uremic hyperparathyroidism. Not surprisingly, deletion of the MEN1 locus at 11q13 or loss of a large portion or an entire chromosome 11 was a common finding. This particular genomic change appears to have a prominent effect on the overall results of gene expression profiling and was present in slightly less than one-half of adenomas. Genomic changes in primary nonfamilial hyperplasia were for the most part restricted to 11q13 deletion or loss of chromosome 11. The third genomic change we identified was 11q23 deletion. This genetic change was relatively independent of other chromosome 11 changes and present in slightly less than one-half of adenomas. 11q23 deletion along with relatively strong CCND1 expression was common in uremic hyperparathyroidism.