Molecular Oncology and Epigenetics Laboratory, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China.
Cancer Biol Ther. 2010 Sep 1;10(5):520-7. doi: 10.4161/cbt.10.5.12726. Epub 2010 Sep 21.
Chromosome 3p harbors multiple tumor-suppressor genes. PLCD1, located at 3p22, encodes an enzyme that mediates regulatory signaling of energy metabolism, calcium homeostasis and intracellular movement. We investigated the epigenetic alterations of PLCD1 and its tumor suppressor function in breast cancer. Frequent downregulation/silencing of PLCD1 was shown in most breast cancer cell lines by using semi-quantitative PCR. Promoter methylation of PLCD1 was detected in 78% (7/9) of cell lines and 52% (13/25) of primary tumors by Methylation-specific PCR (MSP), but not in any tumor adjacent breast tissues and normal breast tissues, which was further confirmed by bisulfite genomic sequencing (BGS). The silencing of PLCD1 could be reversed by pharmacological demethylation, indicating a methylation-mediated mechanism. Ectopic expression of PLCD1 in silenced breast cancer cells significantly inhibited their colony formation. In addition, PLCD1 inhibited tumor cell migration and induced cell cycle G(2)/M arrest. Thus, this study for the first time demonstrates the frequent inactivation of PLCD1 by promoter methylation and its tumor inhibitory function in breast cancer. Tumor-specific methylation of PLCD1 might serve as a biomarker for possible early detection and prognosis prediction of breast cancer.
染色体 3p 上存在多个肿瘤抑制基因。位于 3p22 的 PLCD1 编码一种酶，可介导能量代谢、钙稳态和细胞内运动的调节信号。我们研究了 PLCD1 的表观遗传学改变及其在乳腺癌中的肿瘤抑制功能。通过半定量 PCR 显示，大多数乳腺癌细胞系中 PLCD1 存在下调/失活。通过甲基化特异性 PCR（MSP）检测到 78%（7/9）的细胞系和 52%（13/25）的原发性肿瘤存在 PLCD1 启动子甲基化，但在任何肿瘤旁乳腺组织和正常乳腺组织中均未检测到，这进一步通过亚硫酸氢盐基因组测序（BGS）得到证实。PLCD1 的沉默可以通过药理学去甲基化逆转，表明存在一种甲基化介导的机制。在沉默的乳腺癌细胞中异位表达 PLCD1 可显著抑制其集落形成。此外，PLCD1 抑制肿瘤细胞迁移并诱导细胞周期 G2/M 期阻滞。因此，本研究首次证明了 PLCD1 启动子甲基化的频繁失活及其在乳腺癌中的肿瘤抑制功能。PLCD1 的肿瘤特异性甲基化可能作为乳腺癌早期检测和预后预测的潜在标志物。
