OBJECTIVETo evaluate the antitumour efficacy of shRNA plasmid specifically targeting Jab1 gene.

METHODSThe nude mouse tumor model was made by subcutaneous injection of human laryngeal carcinoma Hep-2 cells. The tumor growth was monitored after intratumoral injection of pJab1, pKB plasmids and saline. Jab1 and p27 expressions in tumour tissues were examined by immunohistochemistry staining and RT-PCR.

RESULTSMean volume of the pJab1-treated tumors was (267.60 ± 88.19) mm(3), significantly less than that of tumors treated with pKB plasmids (832.20 ± 140.39) mm(3) or saline (895.40 ± 145.93) mm(3) (F = 36.73, P < 0.001). Immunohistochemistry showed that the expression of Jab1 protein was significantly reduced in the pJab1-treated group (32.40% ± 5.59%) compared to the control groups, whereas the expression rate of p27 protein in the pJab1 group (76.80% ± 6.30%) was significantly increased compared to the control groups (P < 0.001). The down regulation of Jab1 protein by pJab1 plasmid was consistent with mRNA expression confirmed by RT-PCR. The level of Jab1 mRNA level in the pJab1-treated group (0.65 ± 0.03) was significantly lower than the control groups (F = 558.00, P < 0.001), however, p27 mRNA, was 0.80 ± 0.02, had no significant alteration (F = 1.52,P > 0.05).

CONCLUSIONSThe pJab1 plasmid results in downregulation of Jab1 in an xenograft tumour model of human laryngeal carcinoma Hep-2 cells and significantly inhibits the tumour growth in vivo. This suggests that pJab1 plasmid specifically targeting Jab1 gene expression could be an effective therapy for human laryngeal carcinoma.