INHIBITION OF PROSTATE TUMOR GROWTH INDUCED BY INJECTION OF LPS-TREATED MAT-LU CELLS IN SYNGENEIC COPENHAGEN RATS.

GERARDO GATTI, VIRGINIA ANDREANI, VIRGINIA RIVERO, MARIANA MACCIONI

Córdoba

Congreso; VII Congreso Latinoamericano de Inmunología.; 2005

We have previously shown that TLR-4 is expressed on the rat prostate tumor cell line (MAT-LU). Stimulation of MAT-LU cells with LPS during 48h induces phenotypical and functional changes, promoting NF-kB translocation and inducing the expression of chemokine genes. In this work, we investigated if the treatment of MAT-LU cells with LPS before their injection in syngeneic Copenhaguen rats has any effect on tumor outcome. First, we analyzed if treatment with different doses of LPS influences their proliferation rate or increases their apoptosis levels. Neither proliferation rates (3H thymidine uptake) nor the apoptosis levels (Annexin V-propidium iodide) showed significant variations between MAT-LU cells treated or not with LPS (p=ns in both cases). In vivo experiments performed in athymic nude mice corroborated this data, since the growth and size of tumors induced by injection of MAT-LU cells, treated or not with LPS, did not present significant differences. In contrast, interesting results were detected when tumors were induced in Copenhaguen rats: a strikingly decrease in tumor volume was detected when they were induced by injection of LPS-treated MAT-LU cells (8.15 and 3.79 cm3 in non treated vs. treated MAT-LU induced tumors at the day of sacrifice; p<0.01 ; n =18). Unraveling the role of TLR4 signaling on tumor cells could provide new clues in understanding tumor immunology.