Characterization of TNP-470-induced modifications to cell functions in HUVEC and cancer cells

The aim of the present work is to characterize (both in vitro and in vivo) the influence of TNP-470 on different cell functions involved in angiogenes is and, more particularly, on endothelial cell growth, cell migration, and vessel formation. In addition, a possible direct anti-tumor activity was in vestigated. To this end, we made use in vitro of human umbilical cord endot helial vein (HUVEC) cells and two human cancer cell lines. The TNP-470 effe cts on the growth of cancer cell lines were compared to those of Taxol (an inhibitor of microtubule depolymerization), a cytotoxic reference which als o displays strong antiogenic activity at low (non-toxic) doses. The in vitr o effects were characterized on the mouse mammary MXT adenocarcinoma, on wh ich we also characterized the Influence of three clinically active antitumo r compounds (as cytotoxic references). The purpose of this part of the stud y was to determine the actual TNP-470-related anti-tumor activity and to ev aluate the possible toxic side-effects at the doses at which this compound induces tumor growth inhibition. These investigations were completed by ana lyzing the TNP-470 effect; on HUVEC cell motility and in vitro and in vivo vessel formation. The results show that in vitro, TNP-470 inhibited the gro wth not only of HUVEC, but also of neoplastic cells. Furthermore, TNP-470 c learly inhibited in vitro endothelial cell motility (p < 10(-5)). However, it had only a minor effect (p = 0.02) on the formation of HUVEC cell networ ks on Matrigel(R). In vivo, TNP-470 was able to inhibit tumor growth (on th e MXT model) at a dose (50 mg/kg) associated with toxic side-effects. Histo logical examination showed a significant inhibition of vessel formation (p < 0.001) at high (toxic) and intermediary (nontoxic) doses (50 and 20 mg/kg ). However, we also observed that TNP-470 stimulated lymphocyte proliferati on. Thus, care must be taken with the TNP-470 compound in combination with other anti-tumoral agents in order to avoid certain unfortunate clinical co mplications. (C) 2000 Elsevier Science Inc. All rights reserved.