Qiu Weihua, David Donald, Zhou Bingsen, Chu Peiguo G, Zhang Bohe, Wu Mengchao, Xiao Jiacheng, Han Tianquan, Zhu Zhenggang, Wang Tianxiang, Liu Xiyong, Lopez Richard, Frankel Paul, Jong Ambrose, Yen Yun
Department of Medical Oncology and Therapeutic Research, Gastrointestinal Disease, Pathology, and Biostatistics, City of Hope National Medical Center, Duarte, California 91010, USA.
Am J Pathol. 2003 Jun;162(6):1961-74. doi: 10.1016/s0002-9440(10)64329-5.
In this study, we describe the growth arrest DNA damage-inducible gene 45beta (GADD45beta), whose expression was significantly down-regulated in the hepatocellular carcinoma (HCC) microarray study and confirmed by Northern blot analysis. The results suggested that expression of GADD45beta was decreased in human liver cancer cell lines HepG2 and Hep3B, but not in normal human embryonic liver cell line CL-48 or normal liver tissue. Histochemistry study and real-time PCR further confirmed that GADD45beta staining in HCC was significantly decreased when compared to surrounding non-neoplastic liver tissue. In further studies of multiple human cancer tissues, GADD45beta strongly stained tissues such as colon cancer, breast cancer, prostate cancer, squamous cell cancer, lymphoma, and leiomyosarcoma, suggesting that the decreased expression of GADD45beta is specific to HCC. Eighty-five cases of primary HCC were further examined by immunohistochemistry and statistical analyses demonstrated that HCC scored lower than matched non-neoplastic liver tissues consistently and significantly. No staining occurred in 12.94% of HCC cases (score = 0, n = 11); 42.35% had weak staining (score = 1, n = 36); 27.06% had moderate staining (score = 2, n = 23); and 17.65% had staining as strong as normal tissue (score = 3, n = 15). Overall, surrounding non-neoplastic liver tissue was highly positive for GADD45beta compared to adjacent neoplastic liver tissues (P < 0.01). We further observed that down-regulation of GADD45beta expression was strongly correlated with differentiation (P < 0.01) and high nuclear grade (P < 0.01). Moreover, we found that expression of GADD45beta was inversely correlated to the presence of mutant p53 in HCC tissue (P < 0.05). Thus, the results of our study suggest that GADD45beta, which is down-regulated in most cases of HCC, remains an ideal candidate for development as a molecular marker in the diagnosis of HCC and as a potential therapeutic target.
在本研究中，我们描述了生长停滞和DNA损伤诱导基因45β（GADD45β），其表达在肝细胞癌（HCC）基因芯片研究中显著下调，并经Northern印迹分析证实。结果表明，GADD45β在人肝癌细胞系HepG2和Hep3B中表达降低，但在正常人胚胎肝细胞系CL-48或正常肝组织中未降低。组织化学研究和实时PCR进一步证实，与周围非肿瘤性肝组织相比，HCC中GADD45β染色显著降低。在对多种人类癌症组织的进一步研究中，GADD45β在结肠癌、乳腺癌、前列腺癌、鳞状细胞癌、淋巴瘤和平滑肌肉瘤等组织中染色强烈，表明GADD45β表达降低是HCC特有的。对85例原发性HCC进行了进一步的免疫组织化学检查，统计分析表明，HCC的评分始终显著低于匹配的非肿瘤性肝组织。12.94%的HCC病例无染色（评分=0，n=11）；42.35%有弱染色（评分=1，n=36）；27.06%有中度染色（评分=2，n=23）；17.65%的染色与正常组织一样强（评分=3，n=15）。总体而言，与相邻的肿瘤性肝组织相比，周围非肿瘤性肝组织中GADD45β高度阳性（P<0.01）。我们进一步观察到，GADD45β表达下调与分化（P<0.01）和高核分级（P<0.01）密切相关。此外，我们发现HCC组织中GADD45β的表达与突变型p53的存在呈负相关（P<0.05）。因此，我们的研究结果表明，在大多数HCC病例中下调的GADD45β仍然是作为HCC诊断中的分子标志物和潜在治疗靶点开发的理想候选者。
