中文摘要：

通过在两个具有不同内源性生长抑素受体（SSTR）表达谱的癌细胞系capan-2和A549中过表达SSTR2，用生长抑素类似物（SSA）奥曲肽或者伐普肽（RC-160）处理实验组的癌细胞，对过表达SSTR2和生长抑素类似物的抗肿瘤增殖效果通过细胞增殖实验进行了研究，而且进一步通过免疫印记的方法研究了SSA／SSTR2涉及的信号通路．结果表明，过表达SSTR2明显抑制了内源性SSTR2表达阳性和阴性癌细胞增殖，而单独使用奥曲肽或者伐普肽对癌细胞增殖影响甚微．然而，在过表达SSTR2的癌细胞中奥曲肽或者伐普肽则可明显抑制癌细胞的增殖，而且具有剂量依赖性．深入研究发现SSA／SSTR2是通过细胞周期阻滞和促凋亡来抑制细胞增殖．结果提示SSTR2可作为候选基因用于本身SSTR2表达阳性或阴性肿瘤的基因治疗，细胞内SSTR2的水平可能是影响肿瘤进程和SSA治疗效果的一个关键因素．

英文摘要：

Exogenous human SSTR2 was overexpressed in two cancer cell lines, capan-2 ceils and A549 cells, which have different expression profiles of endogenous SSTRs. The experimental cancer cells were treated with octreotide or RC-160 at different concentrations. The anti-tumor effects of SSTR2 over- expression and the treatment of octreotide/RC-160 were studied by cell proliferation assessment. The potential pathways involved in SST/SSTR2 signaling were investigated using immunoassays. The results presented in this study showed that overexpression of SSTR2 dramatically inhibited the proliferation of both SSTR2-positive and SSTR2-negative cancer cells. Application of octreotide/RC-160 alone resulted in minimal impact on cancer ceil proliferation. However, Octreotide/RC-160 significantly inhibited the proliferation of cancer ceils overexpressing SSTR2 in a dose-dependent fashion. Further investigations demonstrated that SSA/SSTR2 inhibited proliferation via both cell cycle arresting and promoting apoptosis. It suggested that SSTR2 could be a promising candidate for gene therapy for both SSTR2-positive and SSTR2-negative tumors. The cellular level of SSTR2 might be a critical factor that affects both tumor progression and the outcomes of somatostatin analogue treatment.