Expression and silencing of the microtubule-associated protein Tau in breast cancer cells.
Expression and silencing of the microtubule-associated protein Tau in breast cancer cells.
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DOI：
10.1158/1535-7163.mct-10-0780
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发表时间：
2010-11
影响因子：
5.7
通讯作者：
Sikic BI
中科院分区：
文献类型：
--
作者：
Spicakova T;O'Brien MM;Duran GE;Sweet-Cordero A;Sikic BI
据报道，微管相关蛋白（MAP） Tau是转移性乳腺癌紫杉烷临床反应的预测因素。我们从四种人类乳腺癌细胞系（MCF-7、T-47D、MDA-MB-231和BT-549）中产生了八种紫杉烷耐药变体。与T47D和MDA-MB-231亲本细胞相比，四种变体的Tau水平更高。使用特异性的引物，我们发现Tau的0N、1N、2N、3R和4R亚型在抗性变异中过度表达，Tau的外显子6也是如此，但外显子4A或8却没有。为了确定Tau过表达是否会产生对紫杉烷的抗性，我们获得了三个独立的T-47D克隆，稳定地过表达Tau- 3r和Tau- 4r亚型。与单独转染载体的亲本细胞相比，Tau过表达不会导致紫杉烷抗性。然后，我们在三种组成性表达Tau的细胞系（MCF-7和ZR-75-1乳腺癌细胞，以及OVCAR-3卵巢癌细胞）中敲除Tau的表达。与荧光素酶shrna感染的细胞和未感染的亲本细胞相比，慢病毒介导的MCF-7和OVCAR-3细胞中Tau表达的沉默并未导致紫杉烷敏感性增加。在MCF-7和ZR-75-1细胞中，与非靶向对照相比，使用tau特异性sirna的短暂沉默也没有改变紫杉烷的敏感性。这些结果表明，Tau的过表达和缺失都不能调节细胞对紫杉烷的敏感性。虽然Tau过表达已被报道为紫杉烷耐药的预测标志物，但它不太可能是乳腺癌紫杉烷耐药的直接机制。
Microtubule-associated protein (MAP) Tau has been reported to be a predictive factor for clinical response to taxanes in metastatic breast cancer. We generated a panel of eight taxane resistant variants from four human breast cancer cell lines (MCF-7, T-47D, MDA-MB-231 and BT-549). Four variants had higher levels of Tau compared to their T47D and MDA-MB-231 parental cells. Using isoform-specific primers, we found that Tau 0N, 1N, 2N, 3R and 4R isoforms are overexpressed in the resistant variants, as is Tau exon 6 but not exons 4A or 8. To determine whether Tau overexpression produces resistance to taxanes, we derived three independent T-47D clones stably over-expressing Tau-3R and Tau-4R isoforms. Tau overexpression did not result in taxane resistance compared to parental cells transfected with vector alone. We then knocked down Tau expression in three cell lines that expressed Tau constitutively (MCF-7 and ZR-75-1 breast cancer cells, and OVCAR-3 ovarian cancer cells). Lentivirus-mediated silencing of Tau expression in MCF-7 and OVCAR-3 cells did not result in increased taxane sensitivity compared with luciferase shRNA-infected cells and uninfected parental cells. Transient silencing using Tau-specific siRNAs also did not alter taxane sensitivity relative to non-targeting controls in both MCF-7 and and ZR-75-1 cells. These results show that neither overexpression nor depletion of Tau modulate cellular sensitivity to taxanes. Although Tau overexpression has been reported to be a predictive marker of taxane resistance, it is not likely to be a direct mechanism of taxane resistance in breast cancer.