Background: Aristolochic acid I (AAI) has been implicated in urothelial cell carcinoma (UCC) in humans. However, whether AAI promotes invasion/migration of UCC has not been established.
Methods: A study of human UCC TSGH cells cultured with AAI was conducted. Cell viability, the effects of AAI on the activity of matrix metalloproteinase (MMP)-9, the abilities of invasion/migration and the migration-related proteins (Ras, RhoA, ROCK1, PI-3K, pAkt and nuclear factor-kappaB) of the TSGH cells were assessed. The TSGH cells were subcategorized to 1-day or 30-day AAI exposure. An in vivo study using a nude mice xenograft model was employed to test the antitumor effects of Rho kinase inhibitor or Y27632.
Results: A time- and dose-dependent increase in both activity and messenger RNA (mRNA) level of MMP-9 were demonstrated. The mRNA level of urokinase-type plasminogen activator was increased and tissue inhibitor of metalloproteinase-1 was decreased in the cells with 30-day but not 1-day AAI exposure. A dose-dependent enhancement in wound-healing rate and cell migration was demonstrated, especially in the 30-day AAI-exposed cells. Expressions of Ras/RhoA and other migration-related proteins were increased after AAI treatment, which could be inhibited by Y27632. The in vivo results demonstrated that Y27632 was able to attenuate the speed of growth of the inoculated tumors in nude mice.
Conclusion: Clinically, the patients with prolonged AAI exposure are highly associated UCC, our results provided in vitro and in vivo evidence that prolonged AAI exposure enhances invasion and migration of human TSGH cells.