You Qinghua, Geng Yuanyuan, Ye Huiying, Zhu Guixiang, Gao Xiaofang, Zhu Hongbo
Department of Pathology, Shanghai Pudong Hospital, Shanghai 201399, People's Republic of China.
Onco Targets Ther. 2020 Jun 23;13:5955-5965. doi: 10.2147/OTT.S250404. eCollection 2020.
Evidence has been shown that abnormal DNA methylation plays a vital role in the progression of breast cancer via silencing of gene expression. The results of bisulfite sequencing showed that the methylation status of HOPX in breast cancer tissues was higher than that in normal breast cancer tissues, but little known about the biological functions of HOPX in breast cancer.
A total of 13 paired breast cancer and adjacent noncancerous tissues were subjected to bisulfite sequencing. Meanwhile, the methylation levels of cg218995965 and cg24862548 in breast cancer cells were detected by methylation-specific PCR (MSP). Flow cytometry, wound healing and transwell invasion assays were used to detect the apoptosis, migration and invasion in breast cancer cells. In addition, the expressions of HOPX, p21, cyclin D1 and CDK4 in cells were detected with Western blot assay.
Bisulfite sequencing indicated that the CpG sites (cg218995965 and cg24862548) in the HOPX promoter region showed significantly higher methylation in breast cancer tissues. In addition, methylation-specific PCR revealed that HOPX was significantly hypermethylated in breast cancer cell lines MDA-MB-468 and MCF-7. Furthermore, overexpression of HOPX significantly inhibited the proliferation of MDA-MB-468 and MCF-7 cells via inducing the apoptosis. Moreover, upregulation of HOPX markedly inhibited the migration and invasion abilities of MDA-MB-468 cells. Meanwhile, overexpression of HOPX obviously induced cell cycle arrest in MDA-MB-468 cells via upregulation of p21, and downregulation of cyclin D1 and CDK4. Additionally, overexpression of HOPX suppressed tumor growth of breast cancer in vivo.
Our data showed that HOPX, a tumor suppressor, is epigenetically silenced in breast cancer. Overexpression of HOPX could suppress the progression of breast cancer, and thus indicating that it might serve as a potential target for the treatment of patients with breast cancer.
已有证据表明，异常的DNA甲基化通过基因表达沉默在乳腺癌进展中起重要作用。亚硫酸氢盐测序结果显示，乳腺癌组织中HOPX的甲基化状态高于正常乳腺组织，但HOPX在乳腺癌中的生物学功能鲜为人知。
对13对乳腺癌及癌旁非癌组织进行亚硫酸氢盐测序。同时，采用甲基化特异性PCR（MSP）检测乳腺癌细胞中cg218995965和cg24862548的甲基化水平。采用流式细胞术、伤口愈合实验和Transwell侵袭实验检测乳腺癌细胞的凋亡、迁移和侵袭能力。此外，通过蛋白质免疫印迹法检测细胞中HOPX、p21、细胞周期蛋白D1和细胞周期蛋白依赖性激酶4（CDK4）的表达。
亚硫酸氢盐测序表明，HOPX启动子区域的CpG位点（cg218995965和cg24862548）在乳腺癌组织中甲基化程度显著更高。此外，甲基化特异性PCR显示，HOPX在乳腺癌细胞系MDA-MB-468和MCF-7中显著高甲基化。此外，HOPX的过表达通过诱导凋亡显著抑制MDA-MB-468和MCF-
