Assessment of the biological and pharmacological effects of the alpha nu beta3 and alpha nu beta5 integrin receptor antagonist, cilengitide (EMD 121974), in patients with advanced solid tumors.

BACKGROUND: Cilengitide, an antiangiogenic agent that inhibits the binding of integrins alpha(nu)beta(3) and alpha(nu)beta(5) to the extracellular matrix, was studied at two dose levels in cancer patients to determine the optimal biological dose. PATIENTS AND METHODS: The doses of cilengitide were 600 or 1200 mg/m(2) as a 1-h infusion twice weekly every 28 days. A novel dose escalation scheme was utilized that relied upon the biological activity rate. RESULTS: Twenty patients received 50 courses of cilengitide with no dose-limiting toxic effects. The pharmacokinetic (PK) profile revealed a short elimination half-life of 4 h, supporting twice weekly dosing. Of the six soluble angiogenic molecules assessed, only E-selectin increased significantly from baseline. Analysis of tumor microvessel density and gene expression was not informative due to intrapatient tumor heterogeneity. Although several patients with evaluable tumor biopsy pairs did reveal posttreatment increases in tumor and endothelial cell apoptosis, these results did not reach statistical significance due to the aforementioned heterogeneity. CONCLUSIONS: Cilengitide is a well-tolerated antiangiogenic agent. The biomarkers chosen in this study underscore the difficulty in assessing the biological activity of antiangiogenic agents in the absence of validated biological assays.

Technique for assessment of leukocyte adherence to human umbilical vein endothelial cell monolayers.

The interaction between endothelial cells and immune/inflammatory cells plays an important role in the pathogenesis of vascular diseases. Inflammatory cells also activate endothelial cells and release both proliferative and cytotoxic mediators. In order to examine the interaction between leukocytes and endothelial cells and the effect of various drugs, we established the methodology for isolating and culturing the endothelial cells from human umbilical vein. Endothelial cells were harvested by using 0.1% collagenase within 48 hr of collecting the cord. Cells were grown to confluency in 96-well plates in Medium 199 containing 20% fetal calf serum, endothelial cell growth supplement, heparin, and antibiotics. Using this method, we obtained a confluent layer of the cells in all the 96 wells within 48 hr. We then examined the effect of peptides, endothelin-1, substance P, and neurokinin-A on the adherence of human blood neutrophils (purity and viability > 98%) to endothelial monolayers. All the peptides enhanced (p < 0.05) the adherence of neutrophils to endothelial cells in a time-dependent manner. This method of endothelial cell culturing is reliable, reproducible, and effective in evaluating the role of various mediators and drugs on the adherence of various white blood cells to endothelium.