Franzén B, Linder S, Uryu K, Alaiya A A, Hirano T, Kato H, Auer G
Unit of Cell and Molecular Analysis, Karolinska Institute and Hospital, Stockholm, Sweden.
Br J Cancer. 1996 Apr;73(7):909-13. doi: 10.1038/bjc.1996.162.
High molecular weight tropomyosins (tms) are commonly down-regulated in fibroblasts transformed by oncogenes. Previous studies have also demonstrated that specific tm isoforms are down-regulated in human breast carcinoma cell lines. We examined tropomyosin isoforms in cells prepared from non-cancerous breast lesions and primary human breast carcinomas. The average level of expression of all three high molecular weight tm isoforms (tm 1-3) in carcinomas was generally found to be less than 25% of that observed in non-cancerous breast lesions. Interestingly, the expression of tm 1 was found to be 1.7-fold higher in primary tumours with metastatic spread to axillary lymph nodes compared with primary tumours with no evidence of metastasis (p<0.05). Similarly, tm 1 expression was higher in two 12V-H-ras transformed fibroblast cell lines capable of experimental metastasis compared with three weakly metastatic cell lines. We conclude from these studies that expression of high molecular weight tm isoforms is low in primary breast carcinomas, and that metastatic tumours express relatively high levels of tm 1.
高分子量原肌球蛋白（tm）在癌基因转化的成纤维细胞中通常表达下调。先前的研究也表明，特定的tm亚型在人乳腺癌细胞系中表达下调。我们检测了非癌性乳腺病变和原发性人乳腺癌细胞中肌动蛋白异构体的情况。通常发现，癌组织中所有三种高分子量tm异构体（tm 1-3）的平均表达水平不到非癌性乳腺病变中观察到的表达水平的25%。有趣的是，与无转移证据的原发性肿瘤相比，转移至腋窝淋巴结的原发性肿瘤中tm 1的表达高出1.7倍（p<0.05）。同样，与三种低转移细胞系相比，两种能够发生实验性转移的12V-H-ras转化成纤维细胞系中tm 1的表达更高。我们从这些研究中得出结论，原发性乳腺癌中高分子量tm异构体的表达较低，而转移性肿瘤中tm 1的表达水平相对较高。
