Figure 4

Detection of EBV BART miRNAs in plasma samples of mice carrying xenografted NPC tumors (C15, C17, C666-1). Presence of 4 BART miRNAs - miR-BART1-5p and 5 (cluster 1) and miR-BART 7-3p and 13 (cluster 2) - was assessed by real time PCR following multiplex RT. Plasma samples from mice xenografted with an EBV-negative epithelial tumor (CAPI) were used as negative controls. For each type of xenografted tumor, PCR analysis was performed on pools of plasma samples collected from 3 or 4 mice. The cellular miR-146a which is known to be detectable in blood plasma was used as an endogenous reference [23]. Upper panel: amplification plots obtained for miR-BART1-5p and 13 and for mir-146a. ΔRn stands for the magnitude of the fluorescence signal generated during the PCR at each time point (with background correction). Lower panel: histograms presenting the 2^-ΔCT values for miR-BART 1-5p, 5, 7-3p and 13. All 4 BART miRNAs are relatively abundant in plasma samples from mice xenografted with C15 and C666-1 whereas they are at a low level in samples from C17 mice. This is consistent with data obtained from the corresponding tumor and cellular RNAs (see Figure 1). Like for tumor and exosome RNAs, the 2^-ΔCT index is several times higher for miR-BART7-3p than for other BART miRNAs. These data are representative of two similar experiments.