Figure 1

Effect on tumour burden in a mouse bone metastasis model of human breast cancer (MDA-MB-231). Mice received a 21-day timed-release pellets containing 10 mg doxycycline 3 days before intracardiac MDA-MB-231 injections. Other groups of mice received either zoledronic acid (at 0.2 μg per mouse s.c.) every 2 days alone or in combination with doxycycline. A placebo group was also included. Mice were killed 28 days after cell injection. Longitudinal sections of the spine and femora of tumour-bearing animals (n=15 in placebo group, n=12 in doxycycline-group, n=10 in zoledronate-group, n=6 in combination group,) were analysed to determine (A) tumour burden in bone and bone-associated soft tissue tumour burden and (B) average tumour bone burden per evaluated bone (spine, humeri, femora and tibiae). Data represent means±s.e. of the combined values of all animals in each of the groups in at least two separate experiments. ^* Significantly different from corresponding placebo group (P<0.05). ^aSignificantly different from corresponding doxycycline-alone group (P<0.05).^bSignificantly different from corresponding zoledronic acid-alone group (P<0.05).