Figure 4.

PR619 reduces in vivo primary tumor growth and lung metastases development. (A) OS cells were treated or not with 5 or 15 μM PR619, as indicated, for 24 h. After incubation, the levels of polyUb proteins were measured by Western blot analysis as described in Materials and Methods section. Representative blots of three independent experiments are shown. (B–D) Intramuscular paratibial injections of 1.5 × 10⁶ HOS cells, leading to a rapidly growing tumor in bone tissue, were performed in three groups of nude mice treated with vehicle (blue) or PR619 (Green: 0.5 mg/kg, Purple: 2 mg/kg, Red: 10 mg/kg). (B) Tumor volumes were measured two times per week for seven weeks. (C) Bars indicate means tumor volumes of each group measured 49 days after cell injection (mean ± SD; * p < 0.05). (D) The number of lung metastases were counted when the tumor volumes were approximately 2500 mm³ (mean ± SD; ** p < 0.01).