Proteomic Analysis of Ovarian Cancer Proximal Fluids: Validation of Elevated Peroxiredoxin 1 in Patient Peripheral Circulation

Abstract

BackgroundEpithelial ovarian cancer (EOC) is the deadliest gynecologic malignancy in the United States. Unfortunately, a validated protein biomarker-screening test to detect early stage disease from peripheral blood has not yet been developed. The present investigation assesses the ability to identify tumor relevant proteins from ovarian cancer proximal fluids, including tissue interstitial fluid (TIF) and corresponding ascites, from patients with papillary serous EOC and translates these findings to targeted blood-based immunoassays.Methodology/Principal FindingsPaired TIF and ascites collected from four papillary serous EOC patients at the time of surgery underwent immunodepletion, resolution by 1D gel electrophoresis and in-gel digestion for analysis by liquid chromatography-tandem mass spectrometry, which resulted in an aggregate identification of 569 and 171 proteins from TIF and ascites, respectively. Of these, peroxiredoxin I (PRDX1) was selected for validation in serum by ELISA and demonstrated to be present and significantly elevated (p = 0.0188) in 20 EOC patients with a mean level of 26.0 ng/mL (±9.27 SEM) as compared to 4.19 ng/mL (±2.58 SEM) from 16 patients with normal/benign ovarian pathology.Conclusions/SignificanceWe have utilized a workflow for harvesting EOC-relevant proximal biofluids, including TIF and ascites, for proteomic analysis. Among the differentially abundant proteins identified from these proximal fluids, PRDX1 was demonstrated to be present in serum and shown by ELISA to be elevated by nearly 6-fold in papillary serous EOC patients relative to normal/benign patients. Our findings demonstrate the facile ability to discover potential EOC-relevant proteins in proximal fluids and confirm their presence in peripheral blood serum. In addition, our finding of elevated levels of PRDX1 in the serum of EOC patients versus normal/benign patients warrants further evaluation as a tumor specific biomarker for EOC.

Proteomic analysis of non-small cell lung cancer tissue interstitial fluids

“…Celis and colleagues [6] investigated proteins from breast cancer and normal TIF, where it was demonstrated that proteins identified by MS-based proteomics could be externally validated in a tissue microarray containing over 70 breast carcinoma tissue samples [10]. Furthermore, there are lots of reports of TIF in renal cell carcinoma, head and neck squamous carcinoma, and ovarian cancer [4,11,12], but there is limited research on TIF in NSCLC.…”

Thioredoxins, Glutaredoxins, and Peroxiredoxins—Molecular Mechanisms and Health Significance: from Cofactors to Antioxidants to Redox Signaling

“…Corroboratively to these findings, Prx1 knockout mice showed a higher rate of age-dependent malignancies (163). On the contrary, increased levels of Prxs have, for instance, been described for Prx1 in ovarian cancer proximal fluids (299), and Prx3 in lung cancer (387). Srx and Prx4 promoted the progression of human lung cancer (807).…”

Identification of candidate circulating cisplatin-resistant biomarkers from epithelial ovarian carcinoma cell secretomes

“…Ascites is fluid in the peritoneal cavity that commonly accumulates in ovarian cancer patients and represents a complex milieu of detached ovarian cancer cells and soluble protein (Gortzak-Uzan et al , 2008; Kuk et al , 2009; Hoskins et al , 2011), whereas TIF is harvested by ex vivo incubation of finely diced solid tumors in buffered solutions (Celis et al , 2005; Teng et al , 2010; Teng et al , 2011). Approximately 60% of the secretome proteins identified from EOC cells in this study have been previously reported from proteomic studies of ascites and/or ex vivo TIF.…”