Cancer Research Institute, University of South China, Hengyang, China.
Genet Mol Biol. 2012 Jan;35(1):18-26. doi: 10.1590/s1415-47572012005000009. Epub 2012 Feb 2.
STGC3 is a potential tumor suppressor that inhibits the growth of the nasopharyngeal carcinoma cell line CNE2; the expression of this protein is reduced in nasopharyngeal carcinoma compared with normal nasopharyngeal tissue. In this study, we investigated the tumor-suppressing activity of STGC3 in nude mice injected subcutaneously with Tet/pTRE-STGC3/CNE2 cells. STGC3 expression was induced by the intraperitoneal injection of doxycycline (Dox). The volume mean of Tet/pTRE-STGC3/CNE2+Dox xenografts was smaller than that of Tet/pTRE/CNE2+Dox xenografts. In addition, Tet/pTRE-STGC3/CNE2+Dox xenografts showed an increase in the percentage of apoptotic cells, a decrease in Bcl-2 protein expression and an increase in Bax protein expression. A proteomic approach was used to assess the protein expression profile associated with STGC3-mediated apoptosis. Western blotting confirmed the differential up-regulation of prohibitin seen in proteomic analysis. These results indicate that overexpression of STGC3 inhibits xenograft growth in nude mice by enhancing apoptotic cell death through altered expression of apoptosis-related proteins such as Bcl-2, Bax and prohibitin. These data contribute to our understanding of the function of STGC3 in human nasopharyngeal carcinoma and provide new clues for investigating other STGC3-associated tumors.
STGC3 是一种潜在的肿瘤抑制因子，可抑制鼻咽癌细胞系 CNE2 的生长；与正常鼻咽组织相比，这种蛋白在鼻咽癌中的表达降低。在这项研究中，我们在皮下注射 Tet/pTRE-STGC3/CNE2 细胞的裸鼠中研究了 STGC3 的肿瘤抑制活性。通过腹腔注射强力霉素（Dox）诱导 STGC3 表达。Tet/pTRE-STGC3/CNE2+Dox 异种移植物的体积平均值小于 Tet/pTRE/CNE2+Dox 异种移植物。此外，Tet/pTRE-STGC3/CNE2+Dox 异种移植物中凋亡细胞的百分比增加，Bcl-2 蛋白表达减少，Bax 蛋白表达增加。采用蛋白质组学方法评估与 STGC3 介导的细胞凋亡相关的蛋白质表达谱。Western blot 验证了蛋白质组学分析中所见的 prohibitin 的差异上调。这些结果表明，通过改变凋亡相关蛋白（如 Bcl-2、Bax 和 prohibitin）的表达，过表达 STGC3 通过增强凋亡细胞死亡来抑制裸鼠异种移植物的生长。这些数据有助于我们理解 STGC3 在人鼻咽癌中的功能，并为研究其他与 STGC3 相关的肿瘤提供新线索。
