NEW MAMMARY EPITHELIAL AND FIBROBLASTIC CELL CLONES IN COCULTURE FORM STRUCTURES COMPETENT TO DIFFERENTIATE FUNCTIONALLY
NEW MAMMARY EPITHELIAL AND FIBROBLASTIC CELL CLONES IN COCULTURE FORM STRUCTURES COMPETENT TO DIFFERENTIATE FUNCTIONALLY
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DOI：
10.1083/jcb.108.3.1127
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发表时间：
1989-03-01
影响因子：
7.8
通讯作者：
FRIIS, RR
中科院分区：
文献类型：
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作者：
REICHMANN, E;BALL, R;FRIIS, RR
我们已经建立并表征了一种自发永生化、非致瘤性小鼠乳腺细胞系，命名为IM-2。IM-2细胞在添加催乳激素后合成大量的乳蛋白β-酪蛋白。 β-酪蛋白的诱导发生迅速并且不需要任何外源细胞外基质成分。 IM-2 细胞系在形态上具有异质性，可以分为具有上皮细胞和成纤维细胞特征的细胞克隆。在单一培养中，没有一个上皮克隆能够被诱导合成酪蛋白。然而，上皮细胞和成纤维细胞克隆的共培养使上皮细胞能够进行功能性分化。向这些共培养物中添加催乳激素导致β-酪蛋白的合成量与原始IM-2系所见的量相当。利用这种独特的细胞系统，我们研究了导致激素诱导酪蛋白产生的分化不同步骤之间的相互关系。不依赖激素，上皮-成纤维细胞接触导致形成显示层粘连蛋白沉积的特征结构。我们发现位于这些结构中的上皮细胞也表现出细胞角蛋白中间丝多肽水平显着增加。双重免疫荧光显示，细胞可被激素诱导合成酪蛋白，与层粘连蛋白沉积区域精确共定位，并且细胞显示出大大增强的细胞角蛋白表达。这些结果表明，不依赖激素的分化事件是响应细胞间上皮-间质接触而发生的。这些事件反过来又在催乳激素刺激后带来功能分化的能力状态。
We have established and characterized a spontaneously immortalized, nontumorigenic mouse mammary cell line, designated IM-2.IM-2 cells synthesize large amounts of the milk protein .beta.-casein upon addition of lactogenic hormones. The induction of .beta.-casein occurs rapidly and does not require any exogenous extracellular matrix components. The IM-2 cell line is morphologically heterogeneous and could be separated into cell clones with epithelial and fibroblastic characteristics. In monoculture, none of the epithelial clones could be induced to synthesize caseins. Coculture of epithelial and fibroblastic clones, however, rendered the epithelial cells competent to diffentiate functionally; the addition of lactogenic hormones to these cocultures resulted in the synthesis of .beta.-casein in amounts comparable to that seen with the original IM-2 line. Using this unique cell system, we have investigated the interrelationships between different steps in differentiation leading to hormone-induced casein production. Independent of hormones, epithelial-fibroblastic cell contacts led to the formation of characteristic structures showing the deposition of laminin. We found that the epithelial cells located in these structures also exhibited significantly increased levels of cytokeratin intermediate filament polypeptides. Double immunofluorescence revealed that the cells inducible by hormones to synthesize casein, colocalized exactly with the areas of laminin deposition and with the cells showing greatly intensified cytokertain expression. These results suggest that hormone-independent differentiation events take place in response to intercellular epithelial-mesenchymal contacts. These events in turn bring about a state of competence for functional differentiation after lactogenic hormonal stimulation.