International Joint Cancer Institute, The Second Military Medical University, Shanghai, China.
Gastroenterology. 2010 Dec;139(6):2183-2194.e5. doi: 10.1053/j.gastro.2010.06.049. Epub 2010 Jun 20.
BACKGROUND & AIMS: iASPP is an inhibitory member of the ankyrin-repeat-, SH3-domain- and proline-rich-region-containing protein (ASPP) family; iASPP expression is up-regulated in different human tumor types. We explored the molecular mechanism increased expression of iASPP and its role in hepatocellular carcinoma (HCC).
iASPP expression levels in human liver samples and cell lines were determined by polymerase chain reaction, immunoblot, and immunohistochemical analyses. Luciferase reporter, chromatin immunoprecipitation, and electrophoretic mobility shift assays were used to measure transcriptional activation by nuclear factor-κB (NF-κB). Effects on tumor growth were characterized with MTS, soft agar colony formation, and flow cytometry analyses. Tumorigenicity of cells was studied in nude mice.
Compared with normal liver cells or tissues, iASPP was expressed at significantly higher levels in HCC cell lines (9/14) and liver samples from patients with HCC, cirrhosis, or hepatitis B virus infection. Increased expression of iASPP was significantly associated with time to recurrence and survival time of patients with HCC. NF-κB activation increased the expression of iASPP through p65/p50 binding to a putative NF-κB-binding site in the iASPP promoter; hepatitis B virus X gene product might up-regulate expression of iASPP. Transgenic expression of iASPP promoted tumor cell proliferation and resistance to chemotherapeutic drugs in vitro and in vivo.
iASPP is up-regulated in HCC; it is a direct transcription target of NF-κB. Increased iASPP expression contributes to tumor progression by proliferative and antiapoptotic effects. iASPP might be developed as an HCC therapeutic target or to sensitize cancer cells to chemotherapeutic drugs; it might also be used as a prognostic factor.
iASPP 是锚蛋白重复序列、SH3 结构域和富含脯氨酸区域蛋白（ASPP）家族的抑制性成员；iASPP 在不同的人类肿瘤类型中表达上调。我们探讨了 iASPP 表达增加的分子机制及其在肝细胞癌（HCC）中的作用。
通过聚合酶链反应、免疫印迹和免疫组织化学分析测定人肝组织和细胞系中 iASPP 的表达水平。使用荧光素酶报告基因、染色质免疫沉淀和电泳迁移率变动分析来测量核因子-κB（NF-κB）的转录激活。用 MTS、软琼脂集落形成和流式细胞术分析来研究对肿瘤生长的影响。在裸鼠中研究细胞的致瘤性。
与正常肝细胞或组织相比，iASPP 在 HCC 细胞系（9/14）和来自 HCC、肝硬化或乙型肝炎病毒感染患者的肝组织中表达水平显著升高。iASPP 的表达增加与 HCC 患者的复发时间和生存时间显著相关。NF-κB 激活通过 p65/p50 与 iASPP 启动子中推定的 NF-κB 结合位点结合，增加 iASPP 的表达；乙型肝炎病毒 X 基因产物可能上调 iASPP 的表达。iASPP 的转基因表达促进了体外和体内肿瘤细胞的增殖和对化疗药物的耐药性。
iASPP 在 HCC 中上调；它是 NF-κB 的直接转录靶标。iASPP 表达增加通过增殖和抗凋亡作用促进肿瘤进展。iASPP 可作为 HCC 治疗靶点或使癌细胞对化疗药物敏感；也可用作预后因素。
