Identification of blood lipid markers of docetaxel treatment in prostate cancer patients

Docetaxel is commonly used for treatment of castration-resistant prostate cancer. Unfortunately, many prostate cancer patients develop resistance to docetaxel. Clinical markers less invasive than biopsies, such as blood samples, would be ideal for monitoring and predicting patient treatment outcomes to docetaxel. Lipid alterations are often associated with the progression of many cancers, including prostate cancer. This study investigated the use of lipids from whole blood as clinical markers for docetaxel resistance in a small cohort of patients with prostate cancer. Qualitative lipidomics was performed by liquid chromatography-tandem mass spectrometry to assess the lipid composition of prostate cancer cells exposed to docetaxel as well as whole blood from prostate cancer patients before, during and after docetaxel treatment. Three patients had castration resistant prostate cancer, three had castration sensitive prostate cancer, and four had de novo prostate cancer during the extent of the study. Mean decrease accuracy and classical univariate receiving operating characteristic curve analyses were performed to identify potential biomarkers. In total, 245 and 221 altered lipids were identified from a second stage of mass spectrometry analysis of prostate cancer cells and clinical blood samples, respectively. Both models indicated that docetaxel treatment altered ether-linked phosphatidylcholines, lysophosphatidylcholine, diacylglycerols, ceramides, hexosylceramides, and sphingomyelins. The results also indicated several lipid changes were associated with sphingolipid signaling and metabolism, and glycerophospholipid metabolism. Collectively, these data suggest the potential usage of identified lipid species as indicators of docetaxel resistance in prostate cancer.