Figure 4

In vitro propagation of C17 cells and sensitivity to TLR3 agonists combined to RMT5265. C17 NPC cells were dispersed from xenografted tumors and their propagation in vitro was made possible for the first time by adding a Rho kinase inhibitor (Y-27632) to the culture medium. (A) MTT assay was used to determine the growth characteristics of C17 cells cultured in media containing the Rho kinase inhibitor Y-27632 or not. (B) Morphological aspect of C17 cells propagated in vitro under optical microscopy. The aspect of some cells is evocative of mitosis (black arrowheads) and apoptosis (white arrows). C17 cells were stained with HES after cytospin preparation (passage 5 in vitro). (C) The positive EBV status of C17 cells was confirmed by EBERs hybridization, using HeLa and C666-1 cell pellets as negative and positive control, respectively. (D) MTT cell-growth assay on C17 cells treated with poly(I:C) or poly(A:U) (0.25 μg/mL) used either alone or in combination with the Smac-mimetic RMT5265 (200 nM). Excess over Bliss additivism (EOBA) confirms the synergic effects of these combinations. The results are given as mean +/− SD