SLUG is a direct transcriptional repressor of PTEN tumor suppressor.
SLUG is a direct transcriptional repressor of PTEN tumor suppressor.
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DOI：
10.1002/pros.22974
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发表时间：
2015-06-15
期刊：
影响因子：
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通讯作者：
Wu WS
中科院分区：
文献类型：
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作者：
Uygur B;Abramo K;Leikina E;Vary C;Liaw L;Wu WS
PTEN/AKT信号在前列腺癌的发展和前列腺癌干细胞的维持中起着关键作用。其他致癌基因或肿瘤抑制因子如何与该通路相互作用仍有待阐明。SLUG是Snail超家族的一种锌指转录因子，它促进肿瘤转移并决定乳腺干细胞的状态。SLUG在细胞中通过逆转录病毒载体过表达，SLUG和PTEN的敲低由表达shRNA的慢病毒介导。Western blot、RT-PCR和qPCR分析SLUG和PTEN的表达水平。通过荧光素酶报告基因测定来测量PTEN启动子活性。采用ChIP法检测SLUG与PTEN启动子的结合情况。我们发现，SLUG的过表达降低了前列腺癌细胞系22 RV 1和DU 145中PTEN肿瘤抑制因子的表达;相反，SLUG表达的敲低在这些细胞中在蛋白和RNA水平上均升高了PTEN的表达。我们证明了SLUG过表达通过前列腺癌细胞中的近端启动子区域抑制PTEN启动子活性。通过ChIP分析，我们证实SLUG直接结合到覆盖E-box位点的PTEN启动子区域。我们还发现Slug缺陷导致小鼠胚胎成纤维细胞和前列腺组织中PTEN表达增加。更重要的是，我们发现SLUG的过表达增加了前列腺癌细胞系DU 145的耐药性，并且通过shRNA敲低SLUG使DU 145细胞系对化疗药物敏感。我们进一步证明，PTEN敲低可使表达SLUG shRNA的DU 145细胞对抗癌药物的敏感性发生改变。我们提供了令人信服的证据表明，PTEN是SLUG的直接功能靶标。我们的发现为PTEN/AKT通路的调控提供了新的见解，并为前列腺癌的潜在靶向治疗提供了分子基础
PTEN/AKT signaling plays a key role in prostate cancer development and maintenance of prostate cancer stem cells. How other oncogenes or tumor suppressors interact with this pathway remain to be elucidated. SLUG is an zinc finger transcription factor of the Snail superfamily, and it promotes cancer metastasis and determines the mammary stem cell state. SLUG was overexpressed in cells by retroviral vector and knockdown of SLUG and PTEN was mediated by shRNAs-expressing lentiviruses. Expression level of SLUG and PTEN was examined by Western blot, RT-PCR, and qPCR analyses. PTEN promoter activity was measured by luciferase reporter assay. ChIP assay was used to measure the binding between SLUG and the PTEN promoter in vivo. We showed that overexpression of SLUG decreased expression of PTEN tumor repressor in prostate cancer cell lines 22RV1 and DU145; conversely, knockdown of SLUG expression elevated PTEN expresson at both protein and RNA level in these cells. We demonstrated that SLUG overexpression inhibits PTEN promoter activity through the proximal promoter region in prostate cancer cells. By ChIP assay, we confirmed that SLUG directly binds to the PTEN promoter region covering the E-box sites. We also showed that Slug deficiency leads to an increased expression of PTEN in mouse embryo fibroblasts and prostate tissues. Importantly, we found that overexpression of SLUG increases drug resistance of DU145 prostate cancer cell line and knockdown of SLUG by shRNA sensitizes DU145 cell line to chemotherapeutic drugs. We further demonstrated that PTEN knockdown converts drug sensitivity of DU145 cells expressing SLUG shRNA to anticancer drugs. We provide compelling evidence showing that PTEN is a direct functional target of SLUG. Our findings offer new insight in the regulation of the PTEN/AKT pathway and provide a molecular basis for potential targeted therapies of prostate cancer