[Thymosin beta10 expression and actin filament organization in tumor cell lines with different metastatic potential].

Objective: To investigate the expression of thymosin beta10 (Tbeta10) and related changes of actin filament organization in human tumor cell lines with different metastatic potential.

Methods: Four groups of nine human tumor cell lines with different metastatic potential were analyzed for the expression of Tbeta10 mRNA detected by northern-blot and its peptide by immunohistochemical staining. The filamentous actin (F-actin) was stained with TRITC-phalloidin to detect changes in actin organization.

Results: In comparison with the non and/or weakly metastatic counterparts, Tbeta10 was upregulated in highly metastatic human lung cancer, malignant melanoma and breast cancer cell lines. TRITC-phalloidin staining revealed less actin bundles and a fuzzy network of shorter filaments in the highly metastatic tumor cells, while in the non and/or weakly metastatic cancer cell lines, there were thick and orderly arranged actin filaments.

Conclusions: Tbeta10 levels correlate positively with the metastatic phenotype in human tumors currently examined. The increased metastatic potential of tumor cells is accompanied by the loss of F-actin and poorly organized actin skeleton. There is a consistent correlation between the elevated Tbeta10 expression and the disrupted actin skeleton.