Project description:Purpose: The phosphoinositide 3-kinase (PI3K) pathway is fundamental for cell proliferation and survival and is frequently altered and activated in neoplasia, including carcinomas of the lung. In this study we investigated the potential of targeting the catalytic class IA PI3K isoforms in small cell lung cancer (SCLC), which is the most aggressive of all lung cancer types. Experimental Design: The expression of PI3K isoforms in patient specimens was analyzed. The effects on SCLC cell survival and downstream signaling were determined following PI3K isoform inhibition by selective inhibitors or down-regulation by small interfering RNA. Results: Over-expression of the PI3K isoforms p110 -alpha and p110-alpha was shown by immunohistochemistry in primary SCLC tissue samples. Targeting the PI3K p110 -alpha with RNA interference (RNAi) or selective pharmacological inhibitors resulted in strongly affected cell proliferation of SCLC cells in vitro and in vivo, while targeting p110-alph was less effective. Inhibition of p110 -alpha also resulted in increased apoptosis and autophagy, which was accompanied by decreased phosphorylation of Akt and components of the mammalian target of rapamycin (mTOR) pathway, such as the ribosomal S6 protein, and the eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1). A DNA microarray analysis revealed that p110-alpha inhibition profoundly affected the balance of pro- and anti-apoptotic Bcl-2 family proteins. Finally, p110 -alpha inhibition led to impaired SCLC tumor formation and vascularization in vivo. Conclusion: Together our data demonstrate the key involvement of the PI3K isoform p110 -alpha in multiple tumor-promoting processes in SCLC. 3 control samples, 3 samples for two treaments
Project description:Peroxisome proliferator-activated receptor-gamma (PPARg) regulates the interface between cellular lipid metabolism, redox status and organelle differentiation. Following conditional prostatic epithelial knockout of PPARg in mice we observed focal hyperplasia of the epithelium which developed to mouse prostatic intraepithelial neoplasia (mPIN), becoming progressively more severe with time. We selectively knocked down PPARg2 isoform in wild-type mouse prostatic epithelial cells and examined the consequences of this in a tissue recombination model. Histopathologically the results resembled the conditional PPARg KO mouse prostates. Electron microscopy showed accumulated defective lysosomes and autophagic vacuoles in both of PPARg- and g2- deficient cells. Gene expression profiling indicated a major dysregulation of cell cycle control and metabolic signaling networks related to peroxisomal and lysosomal maturation, lipid oxidation and degradation. We conclude that PPARg maintains the maturation and turnover of peroxisomes and lysosomes in prostate epithelium. Disruption of PPARg signaling results in autophagy and oxidative stress during mPIN pathogenesis. The mPrE-PPARg knockout and mPrE-PPARg2 shRNA cells were compared to wildtype mPrE cells. Time (3 days culture) and cell types (x 4) were tested.
Project description:Peroxisome proliferator-activated receptor-gamma (PPARg) regulates the interface between cellular lipid metabolism, redox status and organelle differentiation. Following conditional prostatic epithelial knockout of PPARg in mice we observed focal hyperplasia of the epithelium which developed to mouse prostatic intraepithelial neoplasia (mPIN), becoming progressively more severe with time. We selectively knocked down PPARg2 isoform in wild-type mouse prostatic epithelial cells and examined the consequences of this in a tissue recombination model. Histopathologically the results resembled the conditional PPARg KO mouse prostates. Electron microscopy showed accumulated defective lysosomes and autophagic vacuoles in both of PPARg- and g2- deficient cells. Gene expression profiling indicated a major dysregulation of cell cycle control and metabolic signaling networks related to peroxisomal and lysosomal maturation, lipid oxidation and degradation. We conclude that PPARg maintains the maturation and turnover of peroxisomes and lysosomes in prostate epithelium. Disruption of PPARg signaling results in autophagy and oxidative stress during mPIN pathogenesis.
Project description:Although a promotional role of the androgen receptor (AR) has been implicated in prostate tumorigenesis, the underlying mechanisms by which the AR, as a steroid-hormone receptor, induces prostatic oncogenesis still remain unknown. Conditional expression of the human AR transgene (hARtg) through Osr1 (old skipped related1) driven-Cre develops high-grade prostatic intraepithelial neoplasia (HGPIN) and adenocarcinomas in mice. Single-cell transcriptomic and genetic tracing analyses implicate the prostatic progenitor properties of prostatic Osr1-expressing cells through prostate development. Conditional expression of hARtg in Osr1-expressing basal epithelial cells elevates IGF1 signaling and initiates prostate oncogenesis and PIN formation. Aberrant IGF1 signaling further cumulates Wnt/b-catenin activation in atypical PIN cells to promote tumor development. Specific inhibition of Wnt signaling pathways significantly represses the growth of hARtg-positive prostate tumor cells in ex-vivo and xenograft models. These data elucidate a new and dynamic regulatory loop initiated by aberrant AR signaling altering IGF1 and Wnt signaling pathways in prostate oncogenesis and tumor development.
Project description:Although a promotional role of the androgen receptor (AR) has been implicated in prostate tumorigenesis, the underlying mechanisms by which the AR, as a steroid-hormone receptor, induces prostatic oncogenesis still remain unknown. Conditional expression of the human AR transgene (hARtg) through Osr1 (old skipped related1) driven-Cre develops high-grade prostatic intraepithelial neoplasia (HGPIN) and adenocarcinomas in mice. Single-cell transcriptomic and genetic tracing analyses implicate the prostatic progenitor properties of prostatic Osr1-expressing cells through prostate development. Conditional expression of hARtg in Osr1-expressing basal epithelial cells elevates IGF1 signaling and initiates prostate oncogenesis and PIN formation. Aberrant IGF1 signaling further cumulates Wnt/b-catenin activation in atypical PIN cells to promote tumor development. Specific inhibition of Wnt signaling pathways significantly represses the growth of hARtg-positive prostate tumor cells in ex-vivo and xenograft models. These data elucidate a new and dynamic regulatory loop initiated by aberrant AR signaling altering IGF1 and Wnt signaling pathways in prostate oncogenesis and tumor development.
Project description:Although a promotional role of the androgen receptor (AR) has been implicated in prostate tumorigenesis, the underlying mechanisms by which the AR, as a steroid-hormone receptor, induces prostatic oncogenesis still remain unknown. Conditional expression of the human AR transgene (hARtg) through Osr1 (old skipped related1) driven-Cre develops high-grade prostatic intraepithelial neoplasia (HGPIN) and adenocarcinomas in mice. Single-cell transcriptomic and genetic tracing analyses implicate the prostatic progenitor properties of prostatic Osr1-expressing cells through prostate development. Conditional expression of hARtg in Osr1-expressing basal epithelial cells elevates IGF1 signaling and initiates prostate oncogenesis and PIN formation. Aberrant IGF1 signaling further cumulates Wnt/b-catenin activation in atypical PIN cells to promote tumor development. Specific inhibition of Wnt signaling pathways significantly represses the growth of hARtg-positive prostate tumor cells in ex-vivo and xenograft models. These data elucidate a new and dynamic regulatory loop initiated by aberrant AR signaling altering IGF1 and Wnt signaling pathways in prostate oncogenesis and tumor development.
Project description:Although a promotional role of the androgen receptor (AR) has been implicated in prostate tumorigenesis, the underlying mechanisms by which the AR, as a steroid-hormone receptor, induces prostatic oncogenesis still remain unknown. Conditional expression of the human AR transgene (hARtg) through Osr1 (old skipped related1) driven-Cre develops high-grade prostatic intraepithelial neoplasia (HGPIN) and adenocarcinomas in mice. Single-cell transcriptomic and genetic tracing analyses implicate the prostatic progenitor properties of prostatic Osr1-expressing cells through prostate development. Conditional expression of hARtg in Osr1-expressing basal epithelial cells elevates IGF1 signaling and initiates prostate oncogenesis and PIN formation. Aberrant IGF1 signaling further cumulates Wnt/b-catenin activation in atypical PIN cells to promote tumor development. Specific inhibition of Wnt signaling pathways significantly represses the growth of hARtg-positive prostate tumor cells in ex-vivo and xenograft models. These data elucidate a new and dynamic regulatory loop initiated by aberrant AR signaling altering IGF1 and Wnt signaling pathways in prostate oncogenesis and tumor development.
Project description:Prostate cancer is a heterogeneous disease with a slow progression and a highly variable clinical outcome. The tumor suppressor gene TP53 is frequently mutated in prostate cancer and predictive of an early metastatic dissemination and unfavorable patient outcome. The progression of solid tumors to metastatic cancer is often associated with increased cell plasticity, but the mechanism underlying TP53-loss induced disease aggressiveness is unknown. Here we show that Trp53 deficiency in Pten-null prostatic epithelial cells does not impact the early proliferation of Pten-null epithelial cells and prostatic intraepithelial neoplasia formation, nor growth arrest and senescence entry at later time. Moreover, we demonstrate that it induces epithelial cell plasticity by stimulating IL6 production in cancer-associated fibroblasts, that in turn enhances Jak/Stat signaling in epithelial cells and promotes metastatic dissemination. Thus, TP53 restrains prostate cancer progression by preventing a pro-tumorigenic crosstalk between PTEN-deficient prostatic epithelial cells and the tumor microenvironment.