Thymosin beta 15: a novel regulator of tumor cell motility upregulated in metastatic prostate cancer.

The Dunning rat prostatic carcinoma is a model system where cell motility closely correlates with the metastatic phenotype. We have identified a novel gene, upregulated in the highly motile and metastatic Dunning cancer cell lines, that represents a new member of the thymosin-beta family, thymosin beta 15. Transfection of antisense thymosin beta 15 constructs into rat prostatic carcinoma cells demonstrates that this molecule positively regulates cell motility, a critical component of the metastatic pathway. Thymosin beta 15 levels are elevated in human prostate cancer and correlate positively with the Gleason tumor grade. Thymosin beta 15 may represent a potential new biochemical marker for human prostate cancer progression.