Himelstein B P, Canete-Soler R, Bernhard E J, Muschel R J
Division of Oncology, Childrens Hospital of Philadelphia, PA 19104.
J Cell Sci. 1994 Feb;107 ( Pt 2):477-86. doi: 10.1242/jcs.107.2.477.
Previous studies have correlated release of the 92 kDa type IV collagenase/gelatinase by tumor cells in culture with metastatic potential. We have now demonstrated that the ability of tumor cells that do not express the 92 kDa gelatinase to induce release of this metalloproteinase from normal fibroblasts may also be associated with the metastatic phenotype. A transformed rat embryo cell line, 2.8, failed to release the 92 kDa gelatinase alone in culture, but gave rise to metastatic tumors whose explants contained the 92 kDa gelatinase. In contrast, a non-metastatic transformed cell line, RA3, did not express the 92 kDa gelatinase alone in culture or in tumor explants. To explore the mechanisms that might govern host-tumor cell interactions in this system, we have studied the effects of co-culture of these transformed cell lines with rat embryo fibroblasts (REF) in culture. 92 kDa gelatinase expression was induced by co-culture of 2.8 with REF, but co-culture of the non-metastatic line RA3 with REF did not result in induction of the 92 kDa gelatinase. The 92 kDa gelatinase in these co-cultures was released by the fibroblasts; methanol-fixed 2.8 cells induced 92 kDa gelatinase expression in REF, but fixed REF cells did not induce enzyme expression in 2.8 cells. This suggested that cell contact was required for induction, which was confirmed by showing that 92 kDa gelatinase induction in co-culture was abolished by separating REF from 2.8 by solute-permissive membranes. In addition, REF could not be stimulated to produce the 92 kDa gelatinase by 2.8-derived conditioned medium, by 2.8-derived extracellular matrix, or by isolated matrix components. These data indicate that metastatic tumor cells can induce 92 kDa gelatinase expression in fibroblasts through a mechanism dependent upon cell contact. In situ hybridization of nude mouse tumors derived from these transformed cell lines revealed 92 kDa gelatinase expression in the stroma of tumors from 2.8, but not in tumors from RA3. Therefore, the experiments based on in vitro co-culture of tumor cells and fibroblasts, together with the in situ localization of mRNA to host cells, suggest that host production of the 92 kDa gelatinase may occur in response to direct contact with metastatic tumor cells.
以往的研究已将培养的肿瘤细胞释放92kDaIV型胶原酶/明胶酶与转移潜能联系起来。我们现在已经证明，不表达92kDa明胶酶的肿瘤细胞诱导正常成纤维细胞释放这种金属蛋白酶的能力也可能与转移表型相关。一种转化的大鼠胚胎细胞系2.8，在培养中单独不能释放92kDa明胶酶，但能产生转移瘤，其外植体含有92kDa明胶酶。相反，一种非转移性转化细胞系RA3，在培养中或肿瘤外植体中单独都不表达92kDa明胶酶。为了探索在这个系统中可能控制宿主-肿瘤细胞相互作用的机制，我们研究了这些转化细胞系与大鼠胚胎成纤维细胞（REF）共培养的效果。2.8与REF共培养诱导了92kDa明胶酶的表达，但非转移性细胞系RA3与REF共培养未导致92kDa明胶酶的诱导。这些共培养物中的92kDa明胶酶是由成纤维细胞释放的；甲醇固定的2.8细胞诱导REF中92kDa明胶酶的表达，但固定的REF细胞未诱导2.8细胞中酶的表达。这表明诱导需要细胞接触，溶质允许膜将REF与2.8分开可消除共培养中92kDa明胶酶的诱导，这证实了这一点。此外，2.8来源的条件培养基、2.8来源的细胞外基质或分离的基质成分均不能刺激REF产生92kDa明胶酶。这些数据表明，转移性肿瘤细胞可通过依赖细胞接触的机制诱导成纤维细胞中92kDa明胶酶的表达。对源自这些转化细胞系的裸鼠肿瘤进行原位杂交显示，2.8肿瘤的基质中有92kDa明胶酶表达，而RA3肿瘤中则没有。因此，基于肿瘤细胞与成纤维细胞体外共培养的实验，以及mRNA在宿主细胞中的原位定位，表明宿主产生92kDa明胶酶可能是对与转移性肿瘤细胞直接接触的反应。
