Chaperonin CCT-mediated AIB1 folding promotes the growth of ERα-positive breast cancer cells on hard substrates.
Chaperonin CCT-mediated AIB1 folding promotes the growth of ERα-positive breast cancer cells on hard substrates.
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伴侣蛋白 CCT 介导的 AIB1 折叠促进 ER α 阳性乳腺癌细胞在硬基质上的生长
DOI：
10.1371/journal.pone.0096085
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Jang J
中科院分区：
文献类型：
--
作者：
Chen L;Zhang Z;Qiu J;Zhang L;Luo X;Jang J
临床观察显示雌激素受体α（ERα）阳性肿瘤与骨转移的发生之间存在强相关性，然而，这种相关性的机制仍不清楚。我们用不同的刚性基质培养MCF-7（ERα阳性）。与生长在更硬的基质（100 kPa）上的细胞相比，生长在软基质（10 kPa）上的细胞表现出降低的铺展能力，S和G2/M细胞周期阶段的细胞比例较低，增殖率降低。使用稳定同位素标记的氨基酸（SILAC），我们进一步比较了整个蛋白质组的MCF-7细胞生长在不同的刚度（10和100 kPa）的基板上，发现8个成员的伴侣蛋白CCT的表达增加了至少2倍，在较硬的基板。CCT折叠活性增加，在硬基板相比，软基板。在乳腺癌1（AIB 1）中扩增，在CCT免疫沉淀物中鉴定。AIB 1在100-kPa底物上的CCT折叠能力比在10-和30-kPa底物上增加。此外，使用哺乳动物双杂交蛋白质-蛋白质相互作用测定，我们发现AIB 1蛋白的多聚谷氨酰胺重复序列对于CCT重复序列和AIB 1之间的相互作用是必不可少的。CCT β介导的AIB 1折叠影响细胞面积扩展、生长速率和细胞周期。在MCF-7和T47 D细胞中，c-myc、cyclin D1和PgR基因在硬基质上的表达均高于软基质。ERα和AIB 1可上调c-myc、cyclin D1和PgR基因的mRNA和蛋白表达，17 β-雌二醇可增强这种作用。相反，4-羟基他莫昔芬可以抑制这些作用。总之，我们的研究表明，一些ERα阳性乳腺癌细胞优先生长在更坚硬的基质上。CCT介导的AIB 1折叠似乎参与了乳腺癌细胞的刚性反应，这为骨转移的机制提供了新的见解。
Clinical observations have revealed a strong association between estrogen receptor alpha (ERα)-positive tumors and the development of bone metastases, however, the mechanism underlying this association remains unknown. We cultured MCF-7 (ERα-positive) on different rigidity substrates. Compared with cells grown on more rigid substrates (100 kPa), cells grown on soft substrates (10 kPa) exhibited reduced spreading ability, a lower ratio of cells in the S and G2/M cell cycle phases, and a decreased proliferation rate. Using stable isotope labeling by amino acids (SILAC), we further compared the whole proteome of MCF-7 cells grown on substrates of different rigidity (10 and 100 kPa), and found that the expression of eight members of chaperonin CCT increased by at least 2-fold in the harder substrate. CCT folding activity was increased in the hard substrate compared with the soft substrates. Amplified in breast cancer 1 (AIB1), was identified in CCT immunoprecipitates. CCT folding ability of AIB1 increased on 100-kPa substrate compared with 10- and 30-kPa substrates. Moreover, using mammalian two-hybrid protein-protein interaction assays, we found that the polyglutamine repeat sequence of the AIB1 protein was essential for interaction between CCTζ and AIB1. CCTζ-mediated AIB1 folding affects the cell area spreading, growth rate, and cell cycle. The expressions of the c-myc, cyclin D1, and PgR genes were higher on hard substrates than on soft substrate in both MCF-7 and T47D cells. ERα and AIB1 could up-regulate the mRNA and protein expression levels of the c-myc, cyclin D1, and PgR genes, and that 17 β-estradiol could enhance this effects. Conversely, 4-hydroxytamoxifen, could inhibit these effects. Taken together, our studies demonstrate that some ERα-positive breast cancer cells preferentially grow on more rigid substrates. CCT-mediated AIB1 folding appears to be involved in the rigidity response of breast cancer cells, which provides novel insight into the mechanisms of bone metastasis.
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