Dittharot Kanthanadon, Dakeng Sumana, Suebsakwong Parichat, Suksamrarn Apichart, Patmasiriwat Pimpicha, Promkan Moltira
Office of Research Academic and Innovation, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
Department of Clinical Microscopy, Faculty of Medical Technology, Mahidol University, Nakhon Pathom, Thailand.
Planta Med. 2019 Mar;85(5):370-378. doi: 10.1055/a-0791-1591. Epub 2018 Nov 21.
Breast cancer is a complex disease driven by multiple factors including both genetic and epigenetic alterations. Recent studies revealed that abnormal gene expression induced by epigenetic changes including aberrant promoter methylation plays a critical role in human breast carcinogenesis. Cucurbitacin B has antiproliferative activity against various human breast cancer cells, but the molecular mechanism is not completely understood. In this study, we explore the influence of cucurbitacin B from on the methylation status at the promoter of oncogenes c-Myc, cyclin D1, and survivin in breast cancer cell lines. Growth inhibitory effect of cucurbitacin B on breast cancer cells was assessed by MTT assay and colony formation assay. Methylation status of genomic DNA was determined by methylation-specific PCR. Gene and protein expression levels of all genes studied were analyzed by real-time RT-PCR and western blot. The results indicated that cucurbitacin B could inhibit cell growth in breast cancer cells. The oncogene promoters are usually hypomethylated in cancer cells. Upon cucurbitacin B treatment, upregulation of DNMT1 and obvious heavy methylation in the promoters of c-Myc, cyclin D1, and survivin, which consequently downregulated the expression of all these oncogenes, were observed. Hence, cucurbitacin B proved to be a potential cancer therapeutic agent, in part by inducing hypermethylation and silences the oncogenic activation.
乳腺癌是一种由多种因素驱动的复杂疾病，这些因素包括基因和表观遗传改变。最近的研究表明，由表观遗传变化（包括异常的启动子甲基化）诱导的异常基因表达在人类乳腺癌发生中起关键作用。葫芦素B对多种人类乳腺癌细胞具有抗增殖活性，但其分子机制尚未完全阐明。在本研究中，我们探讨了葫芦素B对乳腺癌细胞系中癌基因c-Myc、细胞周期蛋白D1和生存素启动子甲基化状态的影响。通过MTT法和集落形成试验评估葫芦素B对乳腺癌细胞的生长抑制作用。通过甲基化特异性PCR测定基因组DNA的甲基化状态。通过实时RT-PCR和蛋白质印迹分析所有研究基因的基因和蛋白质表达水平。结果表明，葫芦素B可抑制乳腺癌细胞的生长。癌基因启动子在癌细胞中通常是低甲基化的。用葫芦素B处理后，观察到DNMT1上调以及c-Myc、细胞周期蛋白D1和生存素启动子中明显的高甲基化，这进而下调了所有这些癌基因的表达。因此，葫芦素B被证明是一种潜在的癌症治疗药物，部分原因是它可诱导高甲基化并使致癌激活沉默。
