Statistical analysis was carried out with SPSS 13.0 software (SPSS, Chicago, IL, United States). Statistically significant differences between groups were established using Fisher��s least significant difference test. P < 0.05 BML-275 was considered to be statistically significant. RESULTS Inhibition of tumor growth in PS-ASODN-treated mice Tumor volume and weight were significantly lower in the PS-ASODN group compared with the liposome negative control and saline groups (P < 0.01, Figure 2A and B). Tumor volume and weight in the imatinib group were slightly lower than in the liposome negative control and saline groups, but the difference was not significant (P > 0.05). Inhibition of tumor growth in the PS-ASODN group (59.437%) was significantly greater than in the imatinib (11.

071%) and liposome negative control groups (2.759%) (all relative to tumor growth observed in the saline control group, Figure Figure2C2C). Figure 2 Phosphorothioate antisense oligodeoxynucleotides mediated inhibition of tumor growth in human gastrointestinal stromal tumors (n = 10 tumors per group). Daily intra-tumor injection of phosphorothioate antisense oligodeoxynucleotides (PS-ASODN) and other … Effect of PS-ASODN on telomerase activity Telomerase activity was significantly repressed in the PS-ASODN group compared with the imatinib and liposome negative control groups (P < 0.01, Figure Figure3).3). As expected, administration of imatinib did not significantly affect telomerase activity compared with the liposome negative control group (P > 0.05).

Figure 3 Effect of phosphorothioate antisense oligodeoxynucleotides and other reagents on telomerase activity in gastrointestinal stromal tumors tissues (n = 10 tumors per group). bP < 0.01 vs tumors treated with phosphorothioate antisense oligodeoxynucleotides ... Effect of PS-ASODN on tumor cell apoptosis The percentage of apoptotic cells in tumors was determined by flow cytometry on day 28 after tumor implantation. Apoptosis was significantly higher in the PS-ASODN group (20.751% �� 0.789%) compared with the imatinib (1.637% �� 0.469%), liposome negative control, and saline groups (P < 0.01, Figure Figure4).4). There was no significant difference (P > 0.05) between the imatinib group and the liposome negative control and saline groups. Figure 4 Effect of phosphorothioate antisense oligodeoxynucleotides and other reagents on tumor cell apoptosis (n = 10 tumors per group).

bP < 0.01 vs liposome negative control and imatinib groups. 1: Liposome negative control group; 2: Imatinib group; ... Effect of PS-ASODN on bcl-2 expression OR the level of bcl-2 mRNA Agarose gel electrophoresis was Entinostat used to verify the lengths of the PCR amplification fragments, namely 235 bp for bcl-2 (encoding B-cell lymphoma protein 2) and 99 bp for ��-actin (Figure (Figure5).5). The level of bcl-2 mRNA was significantly downregulated (P < 0.