Evaluation of the use of urinary miRNAs as a tool for diagnosis, prognosis and detection of recurrence in patients with renal cell carcinoma

Abstract

Introduction: Micro RNA's (MIR's) are small ubiquitous non-coding strands of RNA that are thought to be important regulators of cellular gene expression and are found throughout the human biome, including circulating in the blood stream and excreted in the urine. We have previously identified selected MIR's circulating in human serum that are associated with disease recurrence and response to targeted therapy. Further analysis has demonstrated that the source of these circulating MIR's is in fact the tumor cell, and that manipulation of the expression of these MIR's through overexpression vectors and knockdown strategies can dramatically alter cellular gene expression and tumor cell behavior in the microenvironment. MIR's are also excreted in the urine, which is particularly relevant in the case of human kidney cancer, as most tumors of the kidney have direct access to the renal collecting system and are likely to be enriched in the urine of patients with kidney cancer. Hypothesis: Urinary MIR's identified in the urine of kidney cancer patients prior to nephrectomy, that are absent after nephrectomy, maybe be important predictors of prognosis in patients with renal cell carcinoma. Furthermore, persistence or reemergence in the urine of patients with kidney cancer may be a harbinger of clinical recurrence.Experimental Design: We have collected urine samples, before, and at serial time points after, curative nephrectomy in patients with localized and locally advanced renal cell carcinoma. We have over 300 patient specimens collected to date. Gene array technology will be utilized to identify MIR's that are present in the preoperative urine, are lost or down regulated in the postoperative urine, and reappear in the urine at the time of clinical recurrence (either local or metastatic). These identified MIR's expression will be validated in a validated set of urine specimens to confirm their value as predictors of diagnosis, prognosis, and recurrence. Selected MIR's will then be further studied to determine their exact role in renal cell carcinoma biology. We will use lentiviral vectors to both overexpress and knockdown the expression of selected MIR's in our in vitro and in vivo models of human kidney cancer developed at MD Anderson, to determine the role of the specific MIR's identified in human renal cell carcinoma biology. Attributes to be studied include the impact on cellular proliferation, invasion, migration, and tumorogenicity. Furthermore, we will also determine the impact of manipulating the expression of these MIR's on response to systemic targeted therapies in our patient derived xenograft models.Experimental Goals: We hope to identify a small subset of urinary MIR's that may demonstrate utility as potential diagnostic and prognostic markers of human renal cell carcinoma. Further study of them in our in vitro and in vivo models of human kidney cancer in the laboratory may provide further insight into their role in the biology of human renal cell carcinoma. (AU)