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Activation of the PI3K/AKT pathway induces urothelial carcinoma of the renal pelvis: identification in human tumors and confirmation in animal models.

ABSTRACT: Urothelial carcinoma of the renal pelvis is a deadly disease with an unclear tumorigenic mechanism. We conducted gene expression profiling on a set of human tumors of this type and identified a phosphatidylinositol 3-kinase (PI3K)/AKT activation expression signature in 76.9% (n = 13) of our samples. Sequence analysis found both activating mutations of PIK3CA (13.6%, n = 22) and loss of heterozygosity at the PTEN locus (25%, n = 8). In contrast, none of the other subtypes of kidney neoplasms (e.g., clear-cell renal cell carcinoma) harbored PIK3CA mutations (n = 87; P < 0.001). Immunohistochemical analysis of urothelial carcinoma samples found loss of PTEN protein expression (36.4%, n = 11) and elevation of phosphorylated mammalian target of rapamycin (mTOR; 63.6%, n = 11). To confirm the role of the PI3K/AKT pathway in urothelial carcinoma, we generated mice containing biallelic inactivation of Pten in the urogenital epithelia. These mice developed typical renal pelvic urothelial carcinomas, with an incidence of 57.1% in mice older than 1 year. Laser capture microdissection followed by PCR confirmed the deletion of Pten exons 4 and 5 in the animal tumor cells. Immunohistochemical analyses showed increased phospho-mTOR and phospho-S6K levels in the animal tumors. Renal lymph node metastases were found in 15.8% of the animals with urothelial carcinoma. In conclusion, we identified and confirmed an important role for the PI3K/AKT pathway in the development of urothelial carcinoma and suggested that inhibitors of this pathway (e.g., mTOR inhibitor) may serve as effective therapeutic agents.

SUBMITTER: Qian CN

PROVIDER: S-EPMC2783739 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature

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Activation of the PI3K/AKT pathway induces urothelial carcinoma of the renal pelvis: identification in human tumors and confirmation in animal models.

Qian Chao-Nan CN Furge Kyle A KA Knol Jared J Huang Dan D Chen Jindong J Dykema Karl J KJ Kort Eric J EJ Massie Aaron A Khoo Sok Kean SK Vanden Beldt Kristin K Resau James H JH Anema John J Kahnoski Richard J RJ Morreau Hans H Camparo Philippe P Comperat Eva E Sibony Mathilde M Denoux Yves Y Molinie Vincent V Vieillefond Annick A Eng Charis C Williams Bart O BO Teh Bin Tean BT

Cancer research 20091020 21

Urothelial carcinoma of the renal pelvis is a deadly disease with an unclear tumorigenic mechanism. We conducted gene expression profiling on a set of human tumors of this type and identified a phosphatidylinositol 3-kinase (PI3K)/AKT activation expression signature in 76.9% (n = 13) of our samples. Sequence analysis found both activating mutations of PIK3CA (13.6%, n = 22) and loss of heterozygosity at the PTEN locus (25%, n = 8). In contrast, none of the other subtypes of kidney neoplasms (e.g ...[more]

PMID: 19843858

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Project description:Expression profiling by arrays Urothelial carcinoma (UC) can arise at any location along the urothelial tract, including the urethra, bladder, ureter or renal pelvis. Although tumors arising in these various locations demonstrate similar morphology, it is unclear whether the gene expression profiles are similar in the upper tract (ureter and renal pelvis) or in the lower tract (bladder and urethra) carcinomas, especially given their different embryologic origins. As differences may facilitate potentially different screening and treatment modalities, we sought to examine the relationship between urothelial carcinoma of the renal pelvis (rUC) and urothelial carcinoma of the bladder (bUC). Fresh tumor tissue was collected from patients with bUC (n=10) and benign mucosa from the bladder (n=7) was collected from individuals undergoing resection for non-UC conditions for comparison. Gene expression profiles from these samples were determined using high-throughput Affymetrix gene expression microarray chips. Bioinformatic approaches were used to compare gene expression profiles of these samples and those of rUC (n= 14) and normal kidney (n=14) that were mostly used in our previous publication. Using unsupervised analytic approaches, rUC and bUC were indistinguishable. When supervised analytic approach was used, a very small number of potentially differentially expressed genes was identified; these differences were most likely to be limited to a single pathway - the chloride ion binding activity pathway -which was more frequently activated in rUC than in bUC. We found that the gene expression profiles of UCs from the upper and lower tract were extremely similar, suggesting that similar pathogenic mechanisms likely function in the development of these tumors. The differential expression of genes in the identified pathway may represent a potential new avenue for detection of upper tract tumors. Tissue samples with urothelial cell carcinoma from lower tract (bladder) as well as normal references were collected and the gene expression profiles were compared with gene expression profiles of samples in our previously published data set . No technical replicates.

Dataset Information

Activation of the PI3K/AKT pathway induces urothelial carcinoma of the renal pelvis: identification in human tumors and confirmation in animal models.

Publications

Activation of the PI3K/AKT pathway induces urothelial carcinoma of the renal pelvis: identification in human tumors and confirmation in animal models.

Similar Datasets

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