Cytoplasmic accumulation of connexin32 expands cancer stem cell population in human HuH7 hepatoma cells by enhancing its self-renewal
Cytoplasmic accumulation of connexin32 expands cancer stem cell population in human HuH7 hepatoma cells by enhancing its self-renewal
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DOI：
10.1002/ijc.25308
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发表时间：
2011-01-01
影响因子：
6.4
通讯作者：
Enomoto, Katsuhiko
中科院分区：
文献类型：
--
作者：
Kawasaki, Yohei;Omori, Yasufumi;Enomoto, Katsuhiko
虽然肝细胞癌（HCC）中间隙连接蛋白32（Cx 32）介导的间隙连接被消除，但胞浆Cx 32的表达倾向于增加，与恶性程度相对应。在人非转移性HuH 7 HCC细胞中建立Tet-off表达系统，其中细胞质Cx 32通过多西环素（Dox）撤回而过表达，我们先前证明细胞质Cx 32的过表达使HuH 7细胞在小鼠中转移。在我们的研究中，假设细胞质Cx 32诱导的转移可能涉及癌症干细胞（CSC）群体的扩增，我们检查了细胞质Cx 32是否控制HuH 7 Tet-off Cx 32细胞中侧群（SP）的大小。增殖激活细胞分选显示，SP在无Dox的培养基中比在补充Dox的培养基中扩增。虽然胞质Cx 32没有阻止从SP到非SP的成熟，纯化的SP重建一个更大的SP馏分中的Dox-免费的培养基比在Dox-补充的一个。此外，尽管来自HuH 7 Tet-off模拟细胞的SP形成了相似数量的相似尺寸的CSC球，无论是否有Dox，但来自HuH 7 Tet-off Cx 32细胞的SP在无Dox的培养基中比在补充Dox的培养基中形成了更多数量的更大CSC球。总之，这些结果表明，细胞质Cx 32的积累应增强CSC的自我更新，以扩大HCC中的CSC群体。
Although the connexin32 (Cx32)-mediated gap junction is abolished in hepatocellular carcinoma (HCC), the expression of cytoplasmic Cx32 tends to increase in correspondence with the grade of malignancy. Establishing a Tet-off expression system in human nonmetastatic HuH7 HCC cells where cytoplasmic Cx32 was overexpressed by doxycycline (Dox) withdrawal, we previously demonstrated that overexpression of cytoplasmic Cx32 made HuH7 cells metastatic in mice. In our study, hypothesizing that the cytoplasmic Cx32-induced metastasis may involve expansion of the cancer stem cell (CSC) population, we examined whether cytoplasmic Cx32 controlled the size of the side population (SP) in HuH7 Tet-off Cx32 cells. Fluorescence-activated cell sorting revealed that SP was expanded in a Dox-free medium compared with a Dox-supplemented one. Although cytoplasmic Cx32 did not block maturation from SP to non-SP, purified SP reconstituted a larger SP fraction in the Dox-free medium than in the Dox-supplemented one. Furthermore, although SP from HuH7 Tet-off mock cells formed a similar number of CSC spheres of a similar size whether with or without Dox, SP from HuH7 Tet-off Cx32 cells developed a greater number of larger CSC spheres in the Dox-free medium than in the Dox-supplemented one. Taken together, these results suggest that accumulation of cytoplasmic Cx32 should enhance self-renewal of CSC to expand the CSC population in HCC.