scholarly journals Endocytic Adaptor Protein Epsin Is Elevated in Prostate Cancer and Required for Cancer Progression

ISRN Oncology ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Kandice L. Tessneer ◽  
Satish Pasula ◽  
Xiaofeng Cai ◽  
Yunzhou Dong ◽  
Xiaolei Liu ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Mouse Model ◽  
Cancer Cells ◽  
Potential Role ◽  
Adaptor Protein ◽  
Wild Type ◽  
Prostate Cancer Cells ◽  
Prostate Tumorigenesis ◽  
Tramp Mouse ◽  
Mouse Prostate

Epsins have an important role in mediating clathrin-mediated endocytosis of ubiquitinated cell surface receptors. The potential role for epsins in tumorigenesis and cancer metastasis by regulating intracellular signaling pathways has largely not been explored. Epsins are reportedly upregulated in several types of cancer including human skin, lung, and canine mammary cancers. However, whether their expression is elevated in prostate cancer is unknown. In this study, we investigated the potential role of epsins in prostate tumorigenesis using the wild type or epsin-deficient human prostate cancer cells, LNCaP, in a human xenograft model, and the spontaneous TRAMP mouse model in wild type or epsin-deficient background. Here, we reported that the expression of epsins 1 and 2 is upregulated in both human and mouse prostate cancer cells and cancerous tissues. Consistent with upregulation of epsins in prostate tumors, we discovered that depletion of epsins impaired tumor growth in both the human LNCaP xenograft and the TRAMP mouse prostate. Furthermore, epsin depletion significantly prolonged survival in the TRAMP mouse model. In summary, our findings suggest that epsins may act as oncogenic proteins to promote prostate tumorigenesis and that depletion or inhibition of epsins may provide a novel therapeutic target for future prostate cancer therapies.

scholarly journals Regenerated Luminal Epithelial Cells Are Derived from Preexisting Luminal Epithelial Cells in Adult Mouse Prostate

2011 ◽  
Vol 25 (11) ◽  
pp. 1849-1857 ◽  
Author(s):  
June Liu ◽  
Laura E. Pascal ◽  
Sudhir Isharwal ◽  
Daniel Metzger ◽  
Raquel Ramos Garcia ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Epithelial Cells ◽  
Cancer Cells ◽  
Androgen Deprivation Therapy ◽  
Specific Antigen ◽  
Androgen Deprivation ◽  
Genetic Lineage ◽  
Prostate Cancer Cells ◽  
Mouse Prostate ◽  
Luminal Epithelial Cells

Abstract Determining the source of regenerated luminal epithelial cells in the adult prostate during androgen deprivation and replacement will provide insights into the origin of prostate cancer cells and their fate during androgen deprivation therapy. Prostate stem cells in the epithelial layer have been suggested to give rise to luminal epithelium. However, the extent of stem cell participation to prostate regrowth is not clear. In this report, using prostate-specific antigen-CreERT2-based genetic lineage marking/tracing in mice, preexisting luminal epithelial cells were shown to be a source of regenerated luminal epithelial cells in the adult prostate. Prostatic luminal epithelial cells could survive androgen deprivation and were capable of proliferating upon androgen replacement. Prostate cancer cells, typically exhibiting a luminal epithelial phenotype, may retain this intrinsic capability to survive and regenerate in response to changes in androgen signaling, providing part of the mechanism for the ultimate failure of androgen deprivation therapy in prostate cancer.

Mouse prostate tumor inhibition via disruption of murine telomerase: In vivo and in vitro data for a new preclinical cancer model

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e14631-e14631
Author(s):  
T. Xu ◽  
Y. Xu ◽  
R. Lao ◽  
K. He ◽  
L. Xue ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Dna Damage ◽  
Cancer Cells ◽  
Cancer Cell Line ◽  
Telomerase Activity ◽  
Telomerase Rna ◽  
Prostate Cancer Cells ◽  
Mouse Prostate

e14631 Background: Telomerase-interference (TI), a novel therapeutic strategy, exploits the high telomerase activity in prostate cancer by introducing a mutated telomerase RNA (MT-Ter) that encodes toxic telomeres. Until now, TI has been tested by targeting human telomerase in tumor cells xenografted into immuno-deficient mice, an inadequate model for predicting efficacy and toxicity. We designed and validated 2 new TI gene constructs that specifically target murine telomerase RNA (mTER), enabling the study of TI in preclinical mouse models that are immuno-competent and that develop endogenous prostate tumors. Methods: We designed 2 constructs and cloned them into a lentiviral delivery system: MT-mTER and siRNA against wild type mTer (α-mTer-siRNA). Using a mouse prostate cancer cell line, E4, we tested the 2 constructs for expression (RT-PCR), telomerase activity (TRAP), and biologic activity (53bp1 DNA damage staining, MTS growth assay, TUNEL and caspase apoptosis assays), as well as in vivo efficacy (NOD-SCID allografts). Results: We confirmed MT-mTER expression (∼50-fold) and showed that α-mTer-siRNA specifically depleted WT-mTER (80% reduction) but not MT-mTER when the 2 constructs are co-expressed; thus, the 2 constructs in combination effectively substituted MT-mTer for WT-mTer in the mouse prostate cancer cells. MT-mTER caused mutant telomeric repeats (TTTGGG instead of TTAGGG) to be added to the ends of telomeres, resulting in rapid telomeric uncapping marked by 53bp1 DNA damage foci (an average 7.5 foci/cell vs. 1.4 foci/cell in vector control). This, in turn, led to rapid and significant apoptosis (>90% TUNEL and caspase +) and growth inhibition in vitro (90% reduction by MTS) and in vivo (75% reduction in tumor allograft size). Conclusions: We successfully designed and validated MT-mTer and α-mTer-siRNA, 2 novel gene constructs that specifically target and co-opt murine telomerase activity within mouse prostate cancer cells. These constructs offer a significant advantage, as they can be used to investigate TI in immuno-competent mice that develop prostate cancer, thereby modeling actual human disease and testing TI-based therapies in a much more informative and authentic manner. No significant financial relationships to disclose.

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