MSACL 2019 EU Abstract

Self-Classified Topic Area(s): Lipidomics

MALDI-TOF/MS Analyses of Urinary Phospholipids and Lysophospholipids as Potential Diagnostic Biomarkers for Prostate Cancer

Xin Li (1), Kenji Nakayama (1), Takayuki Goto (1), Shusuke Akamatsu (1), Koji Shimizu (2), Osamu Ogawa (1) and Takahiro Inoue (1)
(1) Department of Urology, Graduate School of Medicine, Kyoto University, Kyoto, Japan. (2) Clinical Research Center for Medical Equipment Development, Kyoto University Hospital, Kyoto, Japan.

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Xin Li (Presenter)
Kyoto University

Presenter Bio: My name is Xin LI. I am a third year Ph.D. student at the Department of Urology, Graduate School of Medicine, Kyoto University.

In 2013, I graduated from Shandong University, China where I earned a Bachelor’s degree in Clinical Medicine. I continued my Master course at the same school and got a Master’s degree in Surgery in 2016. After graduation from Shandong University, I have been awarded a Chinese State Scholarship and enrolled in the Ph.D. program at Kyoto University, Japan since 2017.

I have focused on the urinary lipid screening method using MALDI-TOF/MS technique. Our established method has been accepted in an international journal focused on lipid researches.

At present, our research group is applying our detection method to the clinical usage, urinary lipid screening for PCa using MALDI-TOF/MS technique.

Relevant Financial Disclosures (within past 24 months)

No relevant financial relationship(s) to disclose.

Grant/Research Support This study was supported by Grants-in-Aid for Scientific Research (15K10587 and 18H02936) from the Japan Society for the Promotion of Science and by the Research Grant for Collaboration Research Projects from the Shimadzu Corporation.

Salary . KN is a program-specific associate professor in the Department of Urology in the Graduate School of Medicine at Kyoto University and also a principal investigator in the Support Center for Precision Medicine, Shimadzu Techno-Research, Inc.

Discussing Products? NO, presenter will NOT present educational content related to products/services of the ineligible company(ies) listed above.

Conflict mitigation NOT REQUIRED.

Abstract

BACKGROUND & OBJECTIVES
The altered phospholipids in prostate tissues have been reported as potential biomarkers for prostate cancer (PCa) diagnosis or prediction of the biochemical recurrence after surgical treatment in our previous studies. Urinary lipidomics has great potential in clinical diagnostics and prognostics, especially for PCa. Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF/MS) is increasingly used in the lipid research which enables a rapid screening of phospholipids. Therefore, a urinary phospholipid screening was performed utilizing MALDI-TOF/MS analyses in order to search for new biomarker candidates in a non-invasive way.

MATERIALS & METHODS
The lipids were extracted by the acidified Bligh-Dyer method from the digital rectal examination (DRE) urine which contains many kinds of lipids secreted from prostatic microenvironment thus enable the detection of prostate-specific products as sources for potential PCa biomarkers. The urinary lipidomic screening was performed by MALDI-TOF/MS (AXIMA Performance, Shimadzu Kratos Analytical, Manchester, UK) in the urine samples collected from 30 PCa and 30 benign prostatic hyperplasia (BPH) patients after DRE. Lipids were identified by MALDI-TOF/MS2 analyses. The compositions of lysophosphatidylcholine (LPC) and phosphatidylcholine (PC) were compared between the PCa and BPH groups.

RESULTS
The urinary phospholipids including LPC, PC, and sphingomyelin (SM) species were detected by MALDI-TOF/MS and identified by MALDI-TOF/MS2 in a reflectron positive mode. Among them, LPC and PC species were relatively abundant and with good reproducibility in the DRE urine samples. The peaks of synthetic LPC and PC molecules spiked in the urine were detected by MALDI-TOF/MS and a linear correlation was confirmed between their concentrations and peak intensity ratios. The compositions of LPC and PC in the urine samples were statistically significant differences between the PCa and BPH groups.

CONCLUSION
Our comparative screening of phospholipid biomarkers enables the DRE urine samples to be applied for PCa diagnosis. The detection of PC and LPC species in the DRE urine samples is feasible and with good reproducibility. The altered PC and LPC compositions in the DRE urine determined by MALDI-TOF/MS may be used as a simple and non-invasive biomarker for the PCa.