Clinical research of gene therapy against digestive tract cancers by using ras suppressor mutant.

我们以前的研究表明，引入显性负H-ras突变体N116Y，在体外可以抑制各种类型的癌细胞的生长。本研究利用病毒载体将N116Y逆转录病毒表达载体pZIP-NI16Y导入8株K-ras基因突变的人胰腺癌细胞系中，观察N116Y对人胰腺癌细胞和食道癌细胞的生长抑制作用。胰腺癌细胞株的生长受到强烈抑制，表达N116Y的克隆扩散变小，失去了非锚定生长能力。此外，它们在体内不会致癌。N16Y腺病毒(AdCMV-N116Y)感染对所有食道癌细胞系体外生长均有抑制作用。在AdCMV-N116Y病毒感染的细胞中，进入S期的进程被明显阻断，并且没有显示EGF刺激后ERK2的激活。更重要的是，将AdCMV-N116Y直接注射入裸小鼠的食管瘤中，显著抑制了肿瘤的生长，提示N116Y在体内外通过抑制ERK2的激活抑制了人胰腺癌和食道癌的生长，N116Y是一种潜在的针对人胰腺癌和食道癌的基因治疗候选基因。

Our previous studies demonstrated that introduction of a dominant negative H-ras mutant, N116Y,inhibits the growth of various types of cancer cells in vitro. In this study, we testedthe efficacy of N116Y in blocking the growth of human pancreatic and esophageal cancer cells using viral vectors.We transfected an retrovirus-expression vector of N116Y,pZIP-NI16Y,into eight human pancreatic cancer cell lines with K-ras mutations. The growth of the pancreatic cancer cell lines was strongly inhibited, and the N116Y-expressing clones became less spread and lost their anchorage-independent growth ability. Furthermore, they were non-tumorigenic in vivo. Infection with Nl16Y adenovirus (AdCMV-N116Y) inhibitedthe in vitro growth of all esophageal cancer cell lines studied. In the AdCMV-N116Y virus-infected cells, progression into S phase was clearly blocked, and did not show the activation of Erk2 after EGF stimulation. Most importantly, direct injection of AdCMV-N116Y into the esophageal tumors in nude mice suppressed their growth significantly.These observations suggest that N116Y suppresses growth of human pancreatic and esophageal cancer cells in vitro and in vivo through the inhibition of Erk2 activation, and that N116Y is a potential candidate gene for gene therapy against human pancreatic and esophageal cancers.