92 THE JOURNAL OF UROLOGY® Vol. 179, No. 4, Supplement, Sunday, May 18, 2008

apoptosis in RCC tissue. These results suggest that galectin-3 is one of the target molecules for modulating the immune escape of RCC.

Source of Funding: None

260GASTRIN-RELEASING PEPTIDE AND ITS PRECURSOR (proGRP) ARE IMPORTANT GROWTH FACTORS IN RENAL CELL CANCERJoseph J Ischia, Damien M Bolton*, Liesl Ischia, Rachele Lockie, Oneel Patel, Graham Baldwin, Arthur Schulkes. Melbourne, Australia.

INTRODUCTION AND OBJECTIVE: Attention is being focused on the role of various growth factors in the development of renal cancer, and evolving treatments are aimed at inhibiting these factors. Gastrin-releasing peptide (GRP) is a 27 amino acid peptide processed from a 125 amino acid prohormone, proGRP, and may be one such growth factor. GRP plays a role in metabolism, organ development, and behaviour. Importantly, it has been recognised as a potent mitogen in many tumours including small cell lung, pancreatic, breast and prostate

active and is the predominant form in tumour tissues. There is some evidence linking GRP to renal tumorigenesis. Little however is known

and GRP receptors in kidney cancers. METHODS: ACHN, Caki-1 and Caki-2 human renal cancer

cell lines were used to investigate the effects of GRP and proGRP on a number of parameters known to be related to tumorigenesis. The parameters were cell proliferation, MAPK activation and migration. The cell lines were investigated for receptor binding sites and radioimmunoassay was used to determine the amount of GRP and proGRP present. Immunohistochemistry was used to determine the expression of GRP and its receptor in resected human renal cancers.

RESULTS: GRP stimulated proliferation in ACHN and Caki-2 cell lines above control by 47% and 53% respectively. The same cell lines expressed receptors for GRP. ProGRP stimulated ACHN only (by 23%) corresponding with its unique expression of proGRP binding sites. GRP and proGRP stimulated MAPK in ACHN cells by 43% and 119% respectively. GRP and proGRP stimulated migration by153% and 171% respectively. RIA revealed that all three cell lines contain proGRP but not the fully processed GRP in the range of 99-170 fmol/106

cells. Immunohistochemistry revealed that GRP and its receptor are present in normal kidney and a variable expression was observed in renal cancers.

CONCLUSIONS: GRP and proGRP appear to stimulate the growth and migration of renal cancer cell lines. ProGRP is present in renal cancer cell lines and GRP receptors are also present in resected renal cancers. Future studies will determine whether these in vitro effects and observations are relevant to the in vivo situation. In particular studies of the growth of renal cancer xenografts in nude mice in response to GRP/proGRP and antagonists are in progress.

Source of Funding: Royal Australasian College of

261IDENTIFICATION OF A miRNA SIGNATURE IN RENAL CELL CANCERFelix Hillig*, Susanne Kneitz, Nils Eckel, Martin Spahn, Burkhard Kneitz, Hubertus Riedmiller. Wuerzburg, Germany.

of small noncoding RNA gene products called miRNAs has emerged as a powerful approach to identify new cancer classes and predict clinical outcome solely based on gene expression. It has the potential to affect patient diagnosis, staging, prognosis, and treatment. To evaluate the role of miRNAs for the development of RCC we analysed miRNA expression

METHODS: miRNA expression in 8 RCC and adjacent non neoplastic tissue was assessed using microarrays (mirVana miRNAProbe Set, Bioarray 1466V1, Ambion). Expression of selected miRNAswas evaluated by qRT-PCR in 49 tumor samples. The effect of selected miRNAs on cell growth and apoptosis was analysed by transient

RESULTS: In our study we analysed the expression of 384 miRNAs in 8 RCCs and adjacent non neoplastic tissue from patients by miRNA microarrays. We were able to identify a group of differentially expressed miRNAs in RRC samples. Expression of selected miRNAs

deregulated miRNAs we could clearly separate normal versus cancer tissue. RT-PCR analysis of 49 tumor samples showed that overexpression of mir-21 is detectable in more than 80 % of all tumors tested and is associated with the presence of metastases. In addition, we could show that inhibition of mir-21 decreased cell growth and increased apoptosis in vitro.

miRNA signature indicating a role of miRNAs in cancer pathogenesis of RCC. In addition, we showed that miR-21 works as an onco-miR in RCC. Our results suggest that differentially expressed miRNA can be used as diagnostic and prognostic marker of RCC

Source of Funding: None

262MICRORNA EXPRESSION PROFILE IN CLEAR-CELL KIDNEY CANCERDavid Juan*, Gabriela Alexe, Travis Antes, David Foran, Anant Madabhushi, Gyan Bhanot, Charles Delisi, Shridar Ganesan, Louis Liou. Boston, MA, Mountain View, CA, Piscataway, NJ, and New Brunswick, NJ.

INTRODUCTION AND OBJECTIVE: MicroRNAs are a class of noncoding RNAs that regulate protein expression by targeting mRNAfor either translation repression or protein degradation. Accumulatingevidence indicates that dysregulation of microRNAs is associated with

pathogenesis and diagnosis. The aberrant expression of microRNAshas been observed in many cancers, including those in the brain, lung, and pancreas. In this report, we describe a novel procedure designed to identify the global expression pattern of microRNA expression in clear-cell RCC and their patient-matched normal kidney tissue. The

tissue for diagnostic and prognostic reasons. Furthermore, recognition of microRNAs that are differentially expressed between the normal and tumor may help to identify those that are involved in RCC and establish the basis to unravel their pathogenic role.

METHODS: Eighteen clear-cell RCC tissue specimens, along with their patient-matched normal kidney tissue, were obtained from patients at Boston Medical Center immediately after radical nephrectomy. IRB-approved informed consent for the collection of specimens was obtained from all patients. 384 primers pairs were used in a real-time PCR assay to quantify microRNA expression. Statistical analysis was then performed to identify an endogenous control and evaluate expression pattern in RCC vs. normal kidney tissue.

RESULTS: The analysis of 384 microRNAs in 18 samples yielded a clear indication that RCC has an inherently different microRNA

were up-regulated, while 83 microRNAs were down-regulated (p<.01 and FDR<.05). Using bioinformatics, the microRNAs significantly deregulated in this study were found to regulate pathways controlled by classic tumor suppressors and oncogenes including MYC, RAS,

signature composed of 60 microRNAs that was able to distinguish high-

another 10 patients with high level of accuracy. CONCLUSIONS: Given that cancer develops through the

continuous accumulation of genetic and epigenetic alterations, the microRNAs we found deregulated in our study opens a new avenue for better understanding of the pathogenesis of RCC. This is important because these microRNAs can serve not only as prognostic/diagnostic markers, but also as potential targets for RNAi therapy.

Source of Funding: None