Department of Oncology, Affiliated People's Hospital of Jiangsu University, Zhenjiang 212002, Jiangsu Province, China.
World J Gastroenterol. 2012 Dec 28;18(48):7319-26. doi: 10.3748/wjg.v18.i48.7319.
To elucidate high mobility group-box 3 (HMGB3) protein expression in gastric adenocarcinoma, its potential prognostic relevance, and possible mechanism of action.
Ninety-two patients with gastric adenocarcinomas surgically removed entered the study. HMGB3 expression was determined by immunohistochemistry through a tissue microarray procedure. The clinicopathologic characteristics of all patients were recorded, and regular follow-up was made for all patients. The inter-relationship of HMGB3 expression with histological and clinical factors was analyzed using nonparametric tests. Survival analysis was carried out by Kaplan-Meier (log-rank) and multivariate Cox (Forward LR) analyses between the group with overexpression of HMGB3 and the group with low or no HMGB3 expression to determine the prognosis value of HMGB3 expression on overall survival. Further, HMGB3 expression was knocked down by small hairpin RNAs (shRNAs) in the human gastric cancer cell line BGC823 to observe its influence on cell biological characteristics. The MTT method was utilized to detect gastric cancer cell proliferation changes, and cell cycle distribution was analyzed by flow cytometry.
Among 92 patients with gastric adenocarcinomas surgically removed in this study, high HMGB3 protein expression was detected in the gastric adenocarcinoma tissues vs peritumoral tissues (P < 0.001). Further correlation analysis with patients' clinical and histology variables revealed that HMGB3 overexpression was obviously associated with extensive wall penetration (P = 0.005), a positive nodal status (P = 0.004), and advanced tumor-node-metastasis (TNM) stage (P = 0.001). But there was no correlation between HMGB3 overexpression and the age and gender of the patient, tumor localization or histologic grade. Statistical Kaplan-Meier survival analysis disclosed significant differences in overall survival between the HMGB3 overexpression group and the HMGB3 no or low expression group (P = 0.006). The expected overall survival time was 31.00 ± 3.773 mo (95%CI = 23.605-38.395) for patients with HMGB3 overexpression and 49.074 ± 3.648 mo (95%CI = 41.925-57.311) for patients with HMGB3 no and low-level expression. Additionally, older age (P = 0.040), extensive wall penetration (P = 0.008), positive lymph node metastasis (P = 0.005), and advanced TNM tumor stage (P = 0.007) showed negative correlation with overall survival. Multivariate Cox regression analysis indicated that HMGB3 overexpression was an independent variable with respect to age, gender, histologic grade, extent of wall penetration, lymph nodal metastasis, and TNM stage for patients with resectable gastric adenocarcinomas with poor prognosis (hazard ratio = 2.791, 95%CI = 1.233-6.319, P = 0.019). In the gene function study, after HMGB3 was knocked down in the gastric cell line BGC823 by shRNA, the cell proliferation rate was reduced at 24 h, 48 h and 72 h. Compared to BGC823 shRNA-negative control (NC) cells, the cell proliferation rate in cells that had HMGB3 shRNA transfected was significantly decreased (P < 0.01). Finally, cell cycle analysis by FACS showed that BGC823 cells that had HMGB3 knocked down were blocked in G1/G0 phase. The percentage of cells in G1/G0 phase in BGC823 cells with shRNA-NC and with shRNA-HMGB3 was 46.84% ± 1.7%, and 73.03% ± 3.51% respectively (P = 0.001), whereas G2/M cells percentage decreased from 26.51% ± 0.83% to 17.8% ± 2.26%.
HMGB3 is likely to be a useful prognostic marker involved in gastric cancer disease onset and progression by regulating the cell cycle.
阐明高迁移率族蛋白 B3（HMGB3）蛋白在胃腺癌中的表达及其潜在的预后相关性，并探讨其可能的作用机制。
对 92 例接受手术切除的胃腺癌患者进行研究。通过组织微阵列程序，采用免疫组织化学方法测定 HMGB3 的表达。记录所有患者的临床病理特征，并对所有患者进行定期随访。采用非参数检验分析 HMGB3 表达与组织学和临床因素的相关性。通过 Kaplan-Meier（对数秩）和多变量 Cox（向前 LR）分析，在 HMGB3 高表达组和低表达或无表达组之间进行生存分析，以确定 HMGB3 表达对总生存率的预后价值。进一步通过短发夹 RNA（shRNA）在人胃癌细胞系 BGC823 中敲低 HMGB3 的表达，观察其对细胞生物学特性的影响。采用 MTT 法检测胃癌细胞增殖变化，流式细胞术分析细胞周期分布。
在本研究中，对 92 例胃腺癌患者的手术切除标本进行分析，结果显示胃腺癌组织中 HMGB3 蛋白高表达，与癌旁组织相比（P < 0.001）。进一步与患者的临床和组织学变量的相关性分析表明，HMGB3 过表达与广泛的壁穿透（P = 0.005）、阳性淋巴结状态（P = 0.004）和晚期肿瘤-淋巴结-转移（TNM）分期（P = 0.001）明显相关。但 HMGB3 过表达与患者的年龄和性别、肿瘤定位或组织学分级无相关性。统计学 Kaplan-Meier 生存分析显示，HMGB3 过表达组与 HMGB3 低或无表达组的总生存率有显著差异（P = 0.006）。HMGB3 过表达组的预期总生存时间为 31.00 ± 3.773 个月（95%CI = 23.605-38.395），HMGB3 低或无表达组的预期总生存时间为 49.074 ± 3.648 个月（95%CI = 41.925-57.311）。此外，年龄较大（P = 0.040）、广泛的壁穿透（P = 0.008）、阳性淋巴结转移（P = 0.005）和晚期 TNM 肿瘤分期（P = 0.007）与总生存率呈负相关。多变量 Cox 回归分析表明，HMGB3 过表达是影响可切除胃腺癌患者预后的独立变量，与年龄、性别、组织学分级、壁穿透程度、淋巴结转移和 TNM 分期有关（危险比=2.791，95%CI = 1.233-6.319，P = 0.019）。在基因功能研究中，通过 shRNA 在 BGC823 胃细胞系中敲低 HMGB3 后，在 24 h、48 h 和 72 h 时细胞增殖率降低。与 BGC823 shRNA 阴性对照（NC）细胞相比，转染 HMGB3 shRNA 的细胞增殖率明显降低（P < 0.01）。最后，通过 FACS 进行的细胞周期分析显示，敲低 BGC823 细胞中的 HMGB3 后，细胞被阻滞在 G1/G0 期。BGC823 细胞中 shRNA-NC 和 shRNA-HMGB3 的 G1/G0 期细胞百分比分别为 46.84% ± 1.7%和 73.03% ± 3.51%（P = 0.001），而 G2/M 期细胞百分比从 26.51% ± 0.83%降至 17.8% ± 2.26%。
HMGB3 可能通过调节细胞周期成为胃腺癌发病和进展的有用的预后标志物。
