Expression of the extracellular matrix molecule thrombospondin inversely correlates with malignant progression in melanoma, lung and breast carcinoma cell lines
✍ Scribed by Vivian Zabrenetzky; Curtis C. Harris; Patricia S. Steeg; David D. Roberts
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- French
- Weight
- 692 KB
- Volume
- 59
- Category
- Article
- ISSN
- 0020-7136
No coin nor oath required. For personal study only.
✦ Synopsis
Thrombospondin (TSP) is a member of a family of extracellular matrix glycoproteins that may participate in multiple aspects of the metastatic cascade. We report an inverse correlation of steady-state Thbs-I mRNA and protein expression with malignant progression among murine melanoma and human lung and breast carcinoma cell lines. Murine K-I735 melanoma cell lines of low metastatic potential, including K-1735 lines transfected with the murine nm23-I cDNA, expressed higher TSP levels than related highly metastatic lines. In a model system of lung carcinoma malignant progression, immortalized human bronchial epithelial cells expressed higher TSP levels than v-Ki-ras, v-Ha-ras or n-ras transfectants, which in turn expressed higher TSP levels than tumor-derived, more aggressive variants. Among 3 unrelated breast carcinoma cell lines, Thbs-l steady-state mRNA levels were greater in the 2 nonmetastatic lines than the metastatic line. Our data show that malignant progression in some cell lines is associated with reduced TSP expression. The suppressive effects of nm23-I transfection on metastatic potential are also associated with increased TSP expression; ras transfection, which results in increased tumorigenesis, is associated with decreased TSP expression.