Isolation and Identification of Potential Urinary Microparticle Biomarkers of Bladder Cancer

Abstract

Bladder cancer leads to approximately 13,000 deaths annually in the United States. Early disease is often treated with minimal morbidity and has good prognosis, while the opposite is true for advanced disease. Currently, no tools exist for early detection of this cancer. Microparticles are small, subcellular particles released by essentially all cells upon activation and are known to be produced constitutively by cancer cells. Since most bladder cancers originate in the urothelial cells lining the lumen of the organ, we hypothesize that these cells will release microparticles into the urine. The goal of this study was to identify potential biomarkers in the urinary microparticles of individuals with bladder cancer. Urine microparticles from five healthy individuals and four individuals with bladder cancer were isolated. Samples were delipidated by PAGE and trypsin-digested, peptides were extracted, and the proteome was examined by LC-MS/MS using a Thermo Finnigan LTQ and LTQ-FT ion trap mass spectrometer. Protein identification was determined by SEQUEST and relative quantitation was assessed by comparing spectral counts. Eight proteins were elevated in the microparticles from individuals with bladder cancer. They include five proteins associated with the epidermal growth factor receptor pathway, the alpha subunit of GsGTP binding protein, resistin, and retinoic acid-induced protein 3. Further studies will be needed to validate these potential biomarkers.

p66Shc regulates vesicle-mediated secretion in mast cells by affecting F-actin dynamics

“…1B). As the steady-state release of microvesicles is generally low, except for tumor cells [26], this result further supports the notion that p66Shc plays a crucial role in preventing constitutive vesicle budding from the plasma membrane.…”

Microvesicles: mediators of extracellular communication during cancer progression

“…Growing evidence demonstrating their bona fide presence in body fluids, such as blood, urine and ascites (Graves et al, 2004;Piccin et al, 2007;Smalley et al, 2008;Taylor and Gercel-Taylor, 2008), and their potential to serve as indicators in the diagnosis, prognosis and surveillance of a variety of health conditions, has heightened the level of interest in these structures. The function of microvesicles appears to be dependent on the cargo they carry.…”

Therapeutic and diagnostic applications of extracellular vesicles

“…In this respect, the exploitation of comparative omic-studies is fundamental for the detection of new biomarkers. For instance, it was revealed that a panel of eight EV-associated proteins were upregulated in the urine of patients with bladder cancer compared to healthy subjects [237]. Likewise, miRNA profiling of plasma-derived EVs identified a panel of four tumor-specific miRNAs of potential use in a screening test for lung carcinoma [238].…”