Czekierdowski A, Czekierdowska S, Danilos J, Czuba B, Sodowski K, Sodowska H, Szymanski M, Kotarski J
Ist Department of Gynecology, Medical University in Lublin, Poland.
J Physiol Pharmacol. 2008 Sep;59 Suppl 4:53-65.
We aimed to investigate the role of thrombospondin-2 (THBS2) related angiogenic activity in malignant ovarian tumors and to determine if aberrant methylation associated inactivation is involved in down-regulating THBS2 expression in ovarian cancer. The methylation status of the THBS2 promoter region and microvessel density (MVD) was studied in 70 malignant ovarian tumors and in 15 control ovarian samples. A methylation specific PCR (MSP) method was used to distinguish methylated from unmethylated DNA in the promoter regions of the THBS2 gene. MVD was assessed with anti-CD34 antibodies and the results were compared between tumors with average (AVD) and high (HVD) microvessel density. Alterations in the expression of trombospondin-2 were more often seen in early (FIGO stage I and II ) than in late stage tumors (66% vs. 30%, p=0.01). Age, menopausal status, the histological type and tumor grade did not correlate with thrombospondin-2 expression, however, silencing of THBS2 gene was more often seen in higher rather than in lower grade (50% vs. 28%) cancers and in nonserous rather than in serous (43% vs. 32%) tumors. In 81% of THBS2 mRNA-negative tumors, ahypermethylated promoter region of THBS2 was found (p=0.00003). An unmethylated product of the MSP reaction was more often detected in high grade tumors (93% vs. 76%, p=0.04). The incidence of THBS2 hypermethylation was not related to the tumor histological type, but unmethylated THBS2 was more often found in serous rather than in nonserous tumor (96% vs. 74%, p=0.01). The median MVD in malignant the tumor samples was 21,7 (range: 7.6-55.2). In the group with HVD, 54% were THBS2 mRNAnegative, conversely, in the group with AVD tumors only 26% of the cases had undetectable THSB2 mRNA. A significant correlation between microvessel density and the expression of trombospondin-2 (p=0.009) was found. In the samples with HVD, 51% had hypermethylated THBS2, however methylation pattern had no significant influence on microvessel density. In conclusion, hypermethylation might be responsible for altered expression of thrombospondin-2 in ovarian cancer. The THSB2 methylation pattern had no significant influence on microvessel density.
我们旨在研究血小板反应蛋白-2（THBS2）相关血管生成活性在恶性卵巢肿瘤中的作用，并确定异常甲基化相关的失活是否参与卵巢癌中THBS2表达的下调。在70例恶性卵巢肿瘤和15例对照卵巢样本中研究了THBS2启动子区域的甲基化状态和微血管密度（MVD）。采用甲基化特异性PCR（MSP）方法区分THBS2基因启动子区域甲基化和未甲基化的DNA。用抗CD34抗体评估MVD，并比较平均微血管密度（AVD）和高微血管密度（HVD）肿瘤之间的结果。血小板反应蛋白-2表达的改变在早期（国际妇产科联盟分期I和II期）肿瘤中比晚期肿瘤中更常见（66%对30%，p = 0.01）。年龄、绝经状态、组织学类型和肿瘤分级与血小板反应蛋白-2表达无关，然而，THBS2基因沉默在高分级而非低分级（50%对28%）癌症以及非浆液性而非浆液性（43%对32%）肿瘤中更常见。在81%的THBS2 mRNA阴性肿瘤中，发现THBS2启动子区域高度甲基化（p = 0.00003）。在高分级肿瘤中更常检测到MSP反应的未甲基化产物（93%对76%，p = 0.04）。THBS2高度甲基化的发生率与肿瘤组织学类型无关，但未甲基化的THBS2在浆液性肿瘤中比非浆液性肿瘤中更常见（96%对74%，p = 0.01）。恶性肿瘤样本中的MVD中位数为21.7（范围：7.6 - 55.2）。在HVD组中，54%为THBS2 mRNA阴性，相反，在AVD肿瘤组中只有26%的病例检测不到THSB2 mRNA。发现微血管密度与血小板反应蛋白-2的表达之间存在显著相关性（p = 0.009）。在HVD样本中，51%的THBS2高度甲基化，然而甲基化模式对微血管密度没有显著影响。总之，高度甲基化可能是卵巢癌中血小板反应蛋白-2表达改变的原因。THSB2甲基化模式对微血管密度没有显著影响。
