NEOPLASTIC TRANSFORMATION BY CRYSTALLINE SILICA AND OTHER MINERALS

继续对来自胎鼠肺的细胞进行研究 肺泡上皮细胞系，FRLE，其中肿瘤转化 可直接由石英颗粒诱发，而不需要 间充质细胞TGF-β mRNA的表达模式和 在石英转化的细胞和衍生的肿瘤中报道了蛋白质。 在裸小鼠中进行另外的致瘤性测定， 石英处理的细胞和对照细胞。 进行了新的研究， 研究石英诱导的转化机制， 肺泡上皮细胞来源于年轻成人而不是胎儿 老鼠肺由于大鼠肺泡II型细胞通常不能 在培养中保持超过几代，它们被 用含有永生化基因的质粒（SV 40 T抗原或腺病毒2 E1 A）和/或选择性标记。 转染 菌落，根据上皮细胞的形态特征选择 形成铺路样集落的多边形细胞进行扩增， 第5代冻存。 这些新的细胞系已经传代 到目前为止，已经有15次，并保持了正常的形态。 新细胞系的表征和石英诱导的细胞凋亡的研究 细胞毒性和转化正在进行中。 SV 40 Tag转染的 细胞系对石英诱导的毒性表现出更高的敏感性 比E1 A转染的细胞系。

Studies were continued on cells derived from the fetal rat lung alveolar epithelial cell line, FRLE, in which neoplastic transformation can be directly induced by quartz particles, without mediation by mesenchymal cells. The patterns of expression of TGF-beta mRNAs and proteins were reported in quartz-transformed cells and derived tumors. Additional tumorigenicity assays in nude mice were performed for quartz-treated and control cells. New studies were undertaken in order to investigate quartz-induced transformation mechanisms in mature alveolar epithelial cells derived from young adult rather than fetal rat lungs. Since rat alveolar type II cells usually cannot be maintained in culture for more than a few passages, they were transfected with plasmids containing immortalizing genes (either SV40 T antigen or adenovirus 2 E1A) and/or a selective marker. Transfected colonies, selected for morphological characteristics of epithelial polygonal cells forming pavement-like colonies, were expanded and cryopreserved at passage 5. These new cell lines have been passaged 15 times so far, and have maintained normal morphology. Characterization of the new cell lines and studies of quartz-induced cytotoxicity and transformation are under way. The SV40Tag-transfected cell line showed a much higher sensitivity to quartz-induced toxicity than the E1A-transfected cell line.