ABSTRACT
BACKGROUND: Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are bioactive phospholipids with mitogenic and growth factor-like activities that act via specific cell-surface receptors present in many normal and transformed cell types. LPA has recently been implicated as a growth factor present in ascites of ovarian cancer patients. The presence of LPA-like activity and the hypothesis that levels of this bioactivity in effusions of ovarian cancer patients are higher than those in effusions of other cancer patients was studied. MATERIALS AND METHODS: A neurite retraction bioassay in a neuroblastoma cell line previously developed for in vitro detection of LPA activity on cell lines was employed and bioactivity was expressed in virtual LPA-equivalent levels. LPA-equivalent levels were tested in effusions of 62 patients with a range of malignancies, including 13 ovarian cancer patients. Biochemical and clinical parameters were evaluated for correlations with LPA-equivalent levels. RESULTS: Average LPA-equivalent levels were 50.2 microns (range 5.4-200) for all patients, and 94.5 microns (range 15-200) for ovarian cancer patients (P = 0.004). There were no additional independent significant correlations between LPA-equivalent levels in effusions and a range of other biochemical and clinical characteristics. CONCLUSION: These data suggest a role for LPA-like lipids in the peritoneal spread of ovarian cancer and possibly that of other predominantly intraperitoneal malignancies.
Subject(s)
Ascitic Fluid/chemistry , Biomarkers, Tumor/analysis , Lysophospholipids/analysis , Ovarian Neoplasms/metabolism , Pleural Effusion, Malignant/chemistry , Adenocarcinoma/metabolism , Adenocarcinoma/secondary , Ascitic Fluid/pathology , Breast Neoplasms/metabolism , Carcinoma, Non-Small-Cell Lung/metabolism , Female , Head and Neck Neoplasms/metabolism , Humans , Kidney Neoplasms/metabolism , Liver Neoplasms/secondary , Lung Neoplasms/metabolism , Lymphoma, Non-Hodgkin/metabolism , Neoplasms, Unknown Primary/metabolism , Ovarian Neoplasms/pathology , Prognosis , Sensitivity and Specificity , Statistics, NonparametricABSTRACT
A high-performance liquid chromatographic (HPLC) assay is described for the determination of the new antitumour drug N-benzoylstaurosporine (CGP 41 251; I) and four of its potential metabolites in micro-volumes (100 microliters) of plasma. After addition of an internal standard, the compounds were isolated from plasma by liquid-liquid extraction with diisopropyl ether. Chromatography was carried out using a 5 microns LiChrospher C-18 end-capped column (125 x 4.0 mm i.d.) and binary gradient elution with acetonitrile and a triethylamine-containing phosphate buffer (pH 3.6) as solvents. Fluorimetric detection was performed with excitation and emission wavelengths set at 286 and 386 nm, respectively. The absolute recovery was more than 98% for all of the investigated compounds. The limit of detection (LOD) for I and three metabolites was 0.1 ng ml-1 and the lower limit of quantitation (LLQ) was 0.2 ng ml-1 in 100 microliters of plasma. The LOD and LLQ for the fourth metabolite was 0.25 and 0.5 ng ml-1, respectively. The between-day and within-day precisions were always < 15% for all the analytes. A limited pharmacokinetic study in mice treated and with I demonstrated that the method is appropriate for this purpose.