CIBICI   14215
CENTRO DE INVESTIGACION EN BIOQUIMICA CLINICA E INMUNOLOGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
INTRATUMORAL INJECTION OF LIPOPOLYSACCHARIDE REDUCES MELANOMA GROWTH IN TOLL LIKE RECEPTOR 4 DEFICIENT MICE”
Autor/es:
ANDREANI V, RIVERO V, MACCIONI M.
Lugar:
Viña del Mar, Chile
Reunión:
Congreso; Asociación Latinoamericana de Inmunología; 2009
Resumen:
Abstract <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} -->   Local TLR stimulation has long been considered  an attractive approach to induce antitumor immunity.  Intra or peritumoral injections of  LPS, alone or in combination with other agents, have been reported to induce significant arrest of tumor growth due to the activation of antigen presenting cells present in the tumor. We have previously demonstrated that melanoma B16 cells stimulated  in vitro with LPS (1 µg/ml) for 48 h prior to their inoculation inhibits tumor growth  in vivo, increasing the survival of tumor-bearing mice. This inhibition could be seen in mice lacking TLR4 (TLR4lps-del), indicating that this effect depends exclusively on the presence of TLR4 on the tumor cell.  To further evaluate the particular contribution of TLR4 present on tumor cells in antitumoral response we set up two different experimental designs. In the first approach (group 1), C57BL/6 and TLR4lps-del mice were inoculated with 1 x 106 B16 cells and on the day after, 1 μg of LPS was injected intratumorally every other day until day 12. In the second (group 2), 1 μg of LPS was injected intratumorally once the tumors had reached a volume of 5 mm3. The injections were repeated 6 times.  In both settings, mice were injected with PBS as control.  Tumor volume was monitored every day. In both experimental models and mice strains, we observed a reduced tumor growth in animals treated with LPS. Therefore, we conclude that there is an effect mediated by TLR4 present on tumor cell themselves, that could also promote an antitumoral immune response.