Tight Junction Proteins Claudin-3 and Claudin-4 Control Tumor Growth and Metastases
Tight Junction Proteins Claudin-3 and Claudin-4 Control Tumor Growth and Metastases
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DOI：
10.1593/neo.12942
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发表时间：
2012-10-01
期刊：
影响因子：
4.8
通讯作者：
Howell, Stephen B.
中科院分区：
文献类型：
--
作者：
Shang, Xiying;Lin, Xinjian;Howell, Stephen B.
紧密连接（TJ）形成的程度是调节运动、侵袭和转移的许多因素之一。紧密连接蛋白是TJ形成和维持所必需的。Claudin-3（CLDN 3）和Claudin-4（CLDN 4）在大多数卵巢癌中高度表达。我们在此报告，CLDN 3和CLDN 4各自用于抑制人2008癌症异种移植物的生长并限制转移潜力。在体外生长速率没有显著变化的情况下，CLDN 3的敲低使体内生长速率增加2.3倍，CLDN 4的敲低使体内生长速率增加3.7倍。这两种类型的肿瘤表现出出生率增加，通过Ki 67染色测量和死亡率降低，通过末端脱氧核苷酸转移酶dUTP缺口末端标记（TUNEL）染色反映。敲除任一紧密连接蛋白并不改变其他TJ蛋白的表达，但通过葡聚糖的跨上皮阻力和细胞旁流量测量确实减少了TJ形成，增强了体外测定中的迁移和侵袭，并增加了静脉内注射后的肺定植。CLDN 3和CLDN 4的敲低分别使总肺转移负荷增加1.7倍和2.4倍。CLDN 3或CLDN 4的缺失导致E-钙粘蛋白mRNA和蛋白质的下调，糖原合成酶激酶-3 β（GSK-3 β）的抑制性磷酸化增加，以及β-连环蛋白途径信号传导的激活，如核β-连环蛋白（蛋白质的去磷酸化形式）和β-连环蛋白/T细胞因子（TCF）的转录活性增加所证明的。我们的结论是，CLDN 3和CLDN 4都介导与体内其他细胞的相互作用，通过维持E-钙粘蛋白的表达和限制β-连环蛋白信号传导来抑制生长和转移潜力。
The extent of tight junction (TJ) formation is one of many factors that regulate motility, invasion, and metastasis. Claudins are required for the formation and maintenance of TJs. Claudin-3 (CLDN3) and claudin-4 (CLDN4) are highly expressed in the majority of ovarian cancers. We report here that CLDN3 and CLDN4 each serve to constrain the growth of human 2008 cancer xenografts and limit metastatic potential. Knockdown of CLDN3 increased in vivo growth rate by 2.3-fold and knockdown of CLDN4 by 3.7-fold in the absence of significant change in in vitro growth rate. Both types of tumors exhibited increase in birth rate as measured by Ki67 staining and decrease in death rate as reflected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Knockdown of either claudin did not alter expression of other TJ protein but did reduce TJ formation as measured by transepithelial resistance and paracellular flux of dextran, enhance migration and invasion in in vitro assays, and increase lung colonization following intravenous injection. Knockdown of CLDN3 and CLDN4 increased total lung metastatic burden by 1.7-fold and 2.4-fold, respectively. Loss of either CLDN3 or CLDN4 resulted in down-regulation of E-cadherin mRNA and protein, increased inhibitory phosphorylation of glycogen synthase kinase-3 beta (GSK-3 beta), and activation of beta-catenin pathway signaling as evidenced by increases in nuclear beta-catenin, the dephosphorylated form of the protein, and transcriptional activity of beta-catenin/T-cell factor (TCF). We conclude that both CLDN3 and CLDN4 mediate interactions with other cells in vivo that restrain growth and metastatic potential by sustaining expression of E-cadherin and limiting beta-catenin signaling.