Regulation of HSulf-1 expression by variant hepatic nuclear factor 1 in ovarian cancer.
Regulation of HSulf-1 expression by variant hepatic nuclear factor 1 in ovarian cancer.
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DOI：
10.1158/0008-5472.can-08-3065
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发表时间：
2009-06-01
期刊：
影响因子：
11.2
通讯作者：
Shridhar V
中科院分区：
文献类型：
--
作者：
Liu P;Khurana A;Rattan R;He X;Kalloger S;Dowdy S;Gilks B;Shridhar V
我们最近发现 HSulf-1 是卵巢癌中下调的基因。我们之前的分析表明，卵巢癌中 HSulf-1 失活部分是由杂合性丢失 (LOH) 和表观遗传沉默介导的。在这里，我们证明转录因子 2 基因（TCF2、HNF-1β）编码的变异肝核因子 1 (vHNF1) 负向调节卵巢癌中 HSulf-1 的表达。免疫印迹分析显示，vHNF1 在 HSulf-1 缺陷的 OV207、SKOV3 和 TOV-21G 细胞系中高表达，但在表达 HSulf-1 的 OSE、OV167 和 OV202 细胞中不高表达。通过 shRNA 介导的 TOV21-G 细胞中 vHNF1 的下调和 OV202 细胞中 vHNF1 表达的瞬时增强，我们发现 vHNF1 抑制卵巢癌细胞系中 HSulf-1 的表达。报告基因测定和染色质免疫沉淀 (ChIP) 实验表明，vHNF1 在 OV207 和 TOV-21G 细胞中的两个不同 vHNF1 响应元件处被特异性招募至 HSulf-1 启动子。此外，通过 MTT 和克隆形成试验确定，OV207 和 TOV-21G 细胞中 vHNF1 表达的下调增加了顺铂或紫杉醇介导的细胞毒性，并且这种效应可通过 HSulf-1 的下调而逆转。此外，与具有非靶向对照shRNA的TOV-21G克隆系的异种移植物相比，携带稳定下调vHNF1的TOV-21G细胞异种移植物的裸鼠对顺铂或紫杉醇诱导的细胞毒性更敏感。最后，组织微阵列上 501 个卵巢肿瘤（包括 140 个透明细胞肿瘤）的免疫组织化学分析表明，vHNF1 与 HSulf-1 表达呈负相关。总的来说，这些结果表明 vHNF1 作为 HSulf-1 表达的抑制因子，可能是卵巢癌治疗的分子靶点。
We recently identified HSulf-1 as a downregulated gene in ovarian carcinomas. Our previous analysis indicated that HSulf-1 inactivation in ovarian cancers is partly mediated by loss of heterozygosity (LOH) and epigenetic silencing. Here we demonstrate that variant hepatic nuclear factor 1 (vHNF1), encoded by transcription factor 2 gene (TCF2, HNF-1β) negatively regulates HSulf-1 expression in ovarian cancer. Immunoblot assay revealed that vHNF1 is highly expressed in HSulf-1 deficient OV207, SKOV3 and TOV-21G cell lines but not in HSulf-1 expressing OSE, OV167 and OV202 cells. By shRNA-mediated downregulation of vHNF1 in TOV21-G cells and transient enhanced vHNF1 expression in OV202 cells, we showed that vHNF1 suppresses HSulf-1 expression in ovarian cancer cell lines. Reporter assay and chromatin immunoprecipitation (ChIP) experiments showed that vHNF1 is specifically recruited to HSulf-1 promoter at two different vHNF1 responsive elements in OV207 and TOV-21G cells. Additionally, downregulation of vHNF1 expression in OV207 and TOV-21G cells increased cisplatin- or paclitaxel-mediated cytotoxicity as determined by both MTT and clonogenic assays and this effect was reversed by downregulation of HSulf-1. Moreover, nude mice bearing TOV-21G cell xenografts with stably downregulated vHNF1 were more sensitive to cisplatin-or paclitaxel-induced cytotoxicity compared to xenografts of TOV-21G clonal lines with nontargeted control shRNA. Finally, immunohistochemical analysis of 501 ovarian tumors including 140 clear cell tumors on tissue microarrays showed that vHNF1 inversely correlates to HSulf-1 expression. Collectively, these results indicate that vHNF1 acts as a repressor of HSulf-1 expression and might be a molecular target for ovarian cancer therapy.