组蛋白标记 H3K9me3 和 H4K20me3 在癌症中的相关性。

Relevance of histone marks H3K9me3 and H4K20me3 in cancer.

机构信息

Institute of Clinical Chemistry, University Hospital Munich-Grosshadern, Munich, Germany.

出版信息

Anticancer Res. 2012 May;32(5):2199-205.

Abstract

BACKGROUND

Circulating nucleosomes are valuable biomarkers for therapy monitoring and estimation of prognosis in cancer disease. While epigenetic and genetic modifications of DNA have been reported in blood of cancer patients, little is known about modifications of histones on circulating nucleosomes.

PATIENTS AND METHODS

Sera of 45 cancer patients (21 colorectal, 4 pancreatic, 15 breast, 5 lung cancer), 12 patients with benign gastrointestinal and inflammatory diseases, and 28 healthy individuals were investigated. Histone modifications were detected by chromatin-immunoprecipitation (ChIP) using antibodies for triple histone methylations at sites H3K9me3 and H4K20me3 and subsequent real-time polymerase chain reaction using primers for the centromeric satellites SAT2. Additionally, the amount of circulating nucleosomes, as well as of carcino-embryonic antigen (CEA) and cancer antigen (CA) 19-9 were measured.

RESULTS

Levels of SAT2 on H3K9me3 (median 0.507 ng/ml) and on H4K20me3 (0.292 ng/ml) were elevated in sera of patients with breast cancer when compared with healthy controls (0.049 and 0.035 ng/ml), but were lower in patients with colorectal cancer (0.039 and 0.027 ng/ml). Both histone marks were correlated with each other but did not correlate with CEA or CA 19-9 in cancer patients. When H3K9me3 and H4K20me3 were normalized to nucleosome content in sera, ratios were significantly higher in all types of cancer as well as in colorectal and breast subtypes when compared with healthy controls. Best discrimination was achieved by normalized H4K20me3 reaching areas under the curves (AUC) of 79.1%, 90.4% and 81.2% in receiver operating characteristic (ROC) curves of these three comparisons.

CONCLUSION

SAT2 levels on H3K9me3 and H4K20me3 are up-regulated in breast cancer and down-regulated in colorectal cancer. Normalization to total nucleosome content enables better discrimination between cancer and control groups.

摘要

背景

循环核小体是癌症疾病治疗监测和预后估计的有价值的生物标志物。虽然已经报道了癌症患者血液中的 DNA 的表观遗传和遗传修饰，但对循环核小体上组蛋白的修饰知之甚少。

患者和方法

研究了 45 名癌症患者（21 名结直肠癌、4 名胰腺癌、15 名乳腺癌、5 名肺癌）、12 名良性胃肠道和炎症性疾病患者和 28 名健康个体的血清。使用针对 H3K9me3 和 H4K20me3 位点的三重组蛋白甲基化的染色质免疫沉淀（ChIP）检测组蛋白修饰，并用针对着丝粒卫星 SAT2 的引物进行实时聚合酶链反应。此外，还测量了循环核小体的量以及癌胚抗原（CEA）和癌症抗原（CA）19-9 的量。

结果

与健康对照组（0.049 和 0.035ng/ml）相比，乳腺癌患者血清中 SAT2 在 H3K9me3（中位数 0.507ng/ml）和 H4K20me3（0.292ng/ml）上的水平升高，但在结直肠癌患者中降低（0.039 和 0.027ng/ml）。这两个组蛋白标记物彼此相关，但与癌症患者的 CEA 或 CA 19-9 无关。当将 H3K9me3 和 H4K20me3 标准化为血清中的核小体含量时，与健康对照组相比，所有类型的癌症以及结直肠和乳腺癌亚型中的比值均显着升高。归一化 H4K20me3 在这三种比较的接收器操作特征（ROC）曲线中达到了 79.1%、90.4%和 81.2%的曲线下面积（AUC），实现了最佳区分。