ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the antitumor efficacy of Ad-TD-RFP for human nasopharyngeal carcinoma cells (C666-1) in vitro and in vivo.</p><p><b>METHODS</b>The oncolytic effects of Ad-TD-RFP and control virus dl11520 on C666-1 cells were determined by cytotoxicity assay (MTS assay). Viral replication of Ad-TD-RFP and dl11520 was detected at different time points (24 h, 48 h, 72 h and 96 h) by tissue culture infective dose (TCID(50)) in C666-1 cells implanted subcutaneously into the flank in each of BALB/c nude mice. The xenografts were injected intratumorally with Ad-TD-RFP or dl1520 to investigate their effects on tumor growth.</p><p><b>RESULTS</b>The concentration for 50% of maximal effect (EC(50)) values of Ad-TD-RFP and dl1520 were (107.6 ± 3.2) pt/cell and (174.1 ± 4.0) pt/cell, respectively (t = 22.6, P < 0.001). The Ad-TD-RFP replication was 3-14 folds more than dl1520 replication at four time points (24 h, 48 h, 72 h and 96 h) in C666-1 cells (t values were 33.6, 23.4, 20.8 and 17.3, respectively, P < 0.001). The average tumor volumes of PBS group, dl1520 group and Ad-TD-RFP group were (1765.5 ± 713.9) mm(3), (1036.9 ± 623.8) mm(3), and (420.8 ± 238.7) mm(3), respectively (F = 12.0, P < 0.05) on day 67 after treatment.</p><p><b>CONCLUSIONS</b>The antitumour efficacy of the novel oncolytic adenovirus Ad-TD-RFP for human nasopharyngeal carcinoma C666-1 cells is superior to that of dl1520 in vitro and in vivo. The outcome of this study provides an experimental basis for the treatment of human nasopharyngeal carcinoma by viral gene therapy.</p>