A study on tumor cell/cell interactions using mouse mammary tumor models

以可移植性乳腺癌TPDMT-4（T4）为材料，在不同条件下传代，建立了T4-O 1320（320）和T4-O 196（96）自主亚系。这些自主肿瘤的特征是在DDD处女小鼠中快速生长，而亲代T4小鼠中没有生长。在三维胶原凝胶培养中，320个细胞形成类似于正常乳腺的分支或星状结构，如T4，但96个细胞生长为圆形肿块，具有结节，并显示出完全不同的形态。然后，将320和96细胞单独培养或胶原酶解离后共培养，以确定是否存在肿瘤细胞/细胞相互作用对生长速率和形态的影响。但是，在单培养和共培养之间没有发现显著差异，表明该技术有必要改进。因此，我们研究了这些细胞之间金属硫蛋白的存在是否不同。据报道，这种金属结合蛋白是与肿瘤细胞异质性相关的待研究的候选因素，与抗肿瘤药物的耐药性有关。该蛋白通过免疫组织学方法进行了研究。观察到在恶性程度较低的亚系肿瘤中蛋白水平较低。甲硫氨酸可能是一个有用的因素，探讨恶性肿瘤细胞和异质性。这种体外系统在人乳腺癌中的应用正在进行中。

The autonomous sublines, T4-O1320(320)and T4-O196(96), were established from the transplantable hormone-dependent mouse mammary tumor, TPDMT-4(T4), by passaging under different conditions. These autonomous tumors were characterized by rapid growth in DDD virgin mice and the parental T4 by no growth in them. In three-dimensional collagen gel culture, 320 cells formed branched or stellate structures similar to normal mammary glands as did T4, but 96 cells grew as rounded masses with knobs and showed completely different morphology. Then, 320 and 96 cells were cultured separately or co-cultured after collagenase dissociation to determine whether there are tumor cell/cell interaction on the growth rate and morphology. However, significant differences between single-culture and co-culture were not investigated on them, showing the necessity of improvement of the technology. Therefore, we studied whether the presence of methallotionein are different or not between these cells. This metal-binding protein, a candidate factor to be investigated relative to heterogeneity of tumor cells, is reported to associate with resistance of anti-tumor drugs. This protein was studied by immuno-histological methods. It was observed that the protein level was the lower in the less malignant subline tumors. Methallotionein seems to be a useful factor to investigate malignancy and heterogeneity of tumor cells. Application of this in vitro system to human breast cancer is in progress.