[Influence of c-kit RNA interference mediated by AdMax adenovirus upon gastrointestinal stromal tumor in nude mice]

To investigate a novel therapeutic regiment for gastrointestinal stromal tumor (GIST) based on c-kit RNA interference (RNAi) under the mediation of AdMax adenovirus.c-kit shRNA, whose lateral sides were decorated with restriction endonuclease sequences, was designed. The joining of c-kit shRNA and PDC316-EGFP-U6 was catalyzed by T4 DNA ligase to construct PDC316-EGFP-U6-C-KIT. Homologous recombination of AdEGFP-U6-C-KIT was performed with AdMax system. Heterotopic transplantation of GIST in nude mice was established. AdEGFP-U6-C-KIT was intratumorally injected in experimental group while blank admax adenovirus AdEGFP-U6 in control group. The volume, inhibition ratio of tumor and CD117 expression of graft tumor were compared between test and control groups.The length of c-kit shRNA was around 50 bp in agarose electrophoresis. Gene sequencing revealed the designed c-kit RNAi sequence in PDC316-EGFP-U6-C-KIT. After transfection with AdEGFP-U6-C-KIT, 293 cells presented green fluorescence. The physical and infective titer of AdEGFP-U6-C-KIT was 5 × 10(11)vp/ml and 5.67 × 10(7) pfu/ml respectively. At the end of test, the mean volume of graft tumor was significantly smaller in test group than in control group [(75 ± 23) vs (989 ± 31) mm(3), P = 0.000]. The inhibition ratio of tumor was 59.6% in test group. Two cases (20%) in test group and 10 (100%) in control group had a positive expression of CD117 (P = 0.001).c-kit RNAi mediated by Admax vector system can inhibit effectively the expression of c-kit gene and the growth of GIST in nude mice.