Tang Bo, Peng Zhi-hong, Jiang Jun
Department of General Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
Zhonghua Wai Ke Za Zhi. 2005 Dec 1;43(23):1545-9.
To observe if ER alpha gene can be induced by 5-aza-CdR in ER alpha negative human breast cancer cell lines (MDA-MB-231 and MDA-MB-435) and the synergistic inhibitory effects of 5-aza-CdR and Tamoxifen on these two cell lines in vitro.
The status of 5'CpG island methylation of ER alpha gene in ER alpha negative (MDA-MB-231 and MDA-MB-435) human breast cancer cell lines and 20 cases of breast cancer tissue was studied by MSP, the expression of ER alpha mRNA was inspected by using RT-PCR after these two cell lines were treated with 5-aza-CdR. Cell proliferation was evaluated by MTT assay, distribution of cell cycle and rate of apoptosis were determined by flow cytometry after these two cell lines were treated with 5-aza-CdR or TAM alone, or in combination in vitro.
The 5'CpG island is methylated in the core promotor of ER alpha gene in ER alpha negative (MDA-MB-231 and MDA-MB-435) human breast cancer cell lines and the methylating rate is 25.0%, 66.7%, 83.3%, 100% in 20 cases of breast cancer tissue of stage I, II, III, IV, respectively. The expression of ER alpha mRNA was induced in these two cell lines after treated with 5-aza-CdR, MTT array showed the proliferation activity of these two cell lines was obviously reduced in 5-aza-CdR group and the inhibitory effect on proliferation was enhanced when 5-aza-CdR combined with TAM compared with control group, the induction of apoptosis was 11.20% and 8.71% respectively by 5-aza-CdR, while the rate of apoptosis is 48.8% and 53.1% when these two cells were treated with 5-aza-CdR combined with TAM.
5-aza-CdR can re-express ER alpha by demethylating and sensitive ER alpha negative human breast cancer cell lines to TAM, 5-aza-CdR and TAM synergistically inhibit proliferation and induce apoptosis in ER alpha negative human breast cancer cell lines, thus offer a new way for the treatment of ER alpha negative breast cancer.
观察5-氮杂-2'-脱氧胞苷（5-aza-CdR）能否诱导雌激素受体α（ERα）基因在ERα阴性的人乳腺癌细胞系（MDA-MB-231和MDA-MB-435）中表达，以及5-aza-CdR与他莫昔芬（Tamoxifen）对这两种细胞系的体外协同抑制作用。
采用甲基化特异性PCR（MSP）研究ERα阴性的人乳腺癌细胞系（MDA-MB-231和MDA-MB-435）及20例乳腺癌组织中ERα基因5'CpG岛甲基化状态；用5-aza-CdR处理这两种细胞系后，采用逆转录-聚合酶链反应（RT-PCR）检测ERα mRNA表达。采用噻唑蓝（MTT）比色法评价细胞增殖；用5-aza-CdR或Tamoxifen单独及联合处理这两种细胞系后，采用流式细胞术检测细胞周期分布及凋亡率。
ERα阴性的人乳腺癌细胞系（MDA-MB-231和MDA-MB-435）中ERα基因核心启动子区5'CpG岛发生甲基化，20例Ⅰ、Ⅱ、Ⅲ、Ⅳ期乳腺癌组织中甲基化率分别为25.0%、66.7%、83.3%、100%。5-aza-CdR处理后，这两种细胞系中ERα mRNA表达均被诱导；MTT比色法显示，5-aza-CdR组这两种细胞系的增殖活性明显降低，5-aza-CdR与Tamoxifen联合应用时对增殖的抑制作用增强；5-aza-CdR单独诱导凋亡率分别为11.20%和8.71%，5-aza-CdR与Tamoxifen联合处理时凋亡率分别为48.8%和53.1%。
5-aza-CdR可通过去甲基化使ERα基因重新表达，使ERα阴性的人乳腺癌细胞系对Tamoxifen敏感，5-aza-CdR与Tamoxifen协同抑制ERα阴性的人乳腺癌细胞系增殖并诱导凋亡，为ERα阴性乳腺癌的治疗提供了新途径。
