Deciphering the peptidome of urine from ovarian cancer patients and healthy controls

Christopher R Smith; Ihor Batruch; Josep Miquel Bauça; Hari Kosanam; Julia Ridley; Marcus Q Bernardini; Felix Leung; Eleftherios P Diamandis; Vathany Kulasingam

doi:10.1186/1559-0275-11-23

Deciphering the peptidome of urine from ovarian cancer patients and healthy controls

Clin Proteomics. 2014 Jun 2;11(1):23. doi: 10.1186/1559-0275-11-23. eCollection 2014.

Authors

Christopher R Smith¹, Ihor Batruch², Josep Miquel Bauça³, Hari Kosanam², Julia Ridley⁴, Marcus Q Bernardini⁵, Felix Leung⁶, Eleftherios P Diamandis⁷, Vathany Kulasingam⁸

Affiliations

¹ Department of Clinical Biochemistry, University Health Network, Toronto, ON, Canada ; Samuel Lunenfeld Research Institute, Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada.
² Samuel Lunenfeld Research Institute, Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada.
³ Servei d'Anàlisis Clíniques, Hospital Universitari Son Espases, Palma de Mallorca, Spain.
⁴ Department of Psychosocial Oncology and Palliative Care, Princess Margaret Cancer Center, University Health Network, Toronto, ON, Canada ; Division of Palliative Care, Department of Community and Palliative Medicine, University of Toronto, Toronto, ON, Canada.
⁵ Department of Obstetrics and Gynecology, University of Toronto, Toronto, ON, Canada.
⁶ Samuel Lunenfeld Research Institute, Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada ; Department of Laboratory Medicine and Pathobiology, University of Toronto, 200 Elizabeth Street, Room 3 EB 362A, Toronto, ON M5G 2C4, Canada.
⁷ Department of Clinical Biochemistry, University Health Network, Toronto, ON, Canada ; Samuel Lunenfeld Research Institute, Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada ; Department of Laboratory Medicine and Pathobiology, University of Toronto, 200 Elizabeth Street, Room 3 EB 362A, Toronto, ON M5G 2C4, Canada.
⁸ Department of Clinical Biochemistry, University Health Network, Toronto, ON, Canada ; Department of Laboratory Medicine and Pathobiology, University of Toronto, 200 Elizabeth Street, Room 3 EB 362A, Toronto, ON M5G 2C4, Canada.

Abstract

Background: Ovarian cancer (OvCa) is the most lethal gynecological malignancy. The emergence of high-throughput technologies, such as mass spectrometry, has allowed for a paradigm shift in the way we search for novel biomarkers. Urine-based peptidomic profiling is a novel approach that may result in the discovery of noninvasive biomarkers for diagnosing patients with OvCa. In this study, the peptidome of urine from 6 ovarian cancer patients and 6 healthy controls was deciphered.

Results: Urine samples underwent ultrafiltration and the filtrate was subjected to solid phase extraction, followed by fractionation using strong cation exchange chromatography. These fractions were analyzed using an Orbitrap mass spectrometer. Over 4600 unique endogenous urine peptides arising from 713 proteins were catalogued, representing the largest urine peptidome reported to date. Each specimen was processed in triplicate and reproducibility at the protein (69-76%) and peptide (58-63%) levels were noted. More importantly, over 3100 unique peptides were detected solely in OvCa specimens. One such promising biomarker was leucine-rich alpha-2-glycoprotein (LRG1), where multiple peptides were found in all urines from OvCa patients, but only one peptide was found in one healthy control urine sample.

Conclusions: Mining the urine peptidome may yield highly promising novel OvCa biomarkers.

Keywords: Biomarker; Early diagnosis; Mass spectrometry; Ovarian cancer; Urine peptidome.