Combined treatment with verapamil, a calcium channel blocker, and B428, a synthetic uPA inhibitor, impairs the metastatic ability of a murine mammary carcinoma

TODARO, LADEDA, BAL DE KIER JOFFÉ AND FARÍAS

ONCOLOGY REPORTS

D.A. Spandidos

Lugar: Atenas; Año: 2003 vol. 10 p. 335 - 340

1021-335X

Urokinase plasminogen activator (uPA) and metalloproteinases (MMP) play a key role in invasion and metastasis, degrading extracellular matrix compounds and modulating tumor cell motility. Their regulation is an attractive therapeutic target for controlling tumor metastasis. Previously we have demonstrated that urokinase overexpression in murine mammary tumor cells is regulated by a Ca2+-dependent pathway and that blockage of Ca2+ channels by verapamil partially inhibited their invasive and metastatic ability. Besides, the catalytic inhibition of uPA by a synthetic uPA inhibitor B-428 reduced local tumor invasiveness but not tumor cell dissemination. Here we evaluate the effect of a combined treatment with Verapamil and B-428 on the murine mammary carcinoma F3II behavior in vivo and in vitro. In vivo, administration of the combined treatment was not associated to an overt toxicity. Only the daily combined treatment, beginning after tumor take, reduced the incidence and the number of spontaneous lung metastasis, while no differences were found in the subcutaneous growth of the primary tumor. Interestingly, a remarkable reduction in plasma MMP-9 activity was found associated to metastasis impairment. In addition, the number of experimental lung metastasis was also significantly diminished, respect to the control group, only when both compounds were co-administered daily, beginning three days after iv tumor cells injection. In vitro, both compounds, either separately or combined, could inhibit secreted uPA activity. F3II cells migration was significantly inhibited (about 45 %) by incubation with 50 ìM Verapamil, 15 ìM B-428 or the co-treatment with 25 µM verapamil + 7.5 µM B-428. The number of spread cells was also significantly reduced when F3II cells were exposed to the compounds, with an additive effect when verapamil+B-428 combination was used. The combination of two compounds acting through different molecular targets may be useful to improve the control of metastatic dissemination.