Fig. 1.

Impact of repeated exposure to chemotherapy on the angiogenic potential of endothelial cells. a Doubling time of the 6 endothelial subclones established by incubating BMH29L endothelial cells for 100 days with no drug (Ctrl-LDM and Ctrl-MTD) or with vinblastine (VLB) or etoposide (VP16) following a low-dose metronomic (LDM) schedule (i.e. treatment 5 days/week with highest non-toxic concentration) or a maximum tolerated dose (MTD) schedule (i.e. treatment every 2 weeks with IC₈₀). Columns means of four individual experiments, bars SE. Statistics were calculated by comparing drug-treated cells with control untreated cells, unless indicated otherwise; *p < 0.05; **p < 0.01. b Representative photographs of the 6 BMH29L subclones following 8 h incubation on Matrigel. Vascular structures were imaged on a Zeiss Axiovert 200 M using a 5X objective. Percentage of angiogenesis inhibition as compared to control cells is indicated; NS non-significant, Scale bar 250 μm