Introduction. Homodynamic factors play crucial roles in vascular remodeling, healing, and disease formation. However, the underlying molecular mechanisms are largely unknown. The aim of this study was to test the hypothesis that cyclic strain could affect vascular cell differentiation or transdifferentiation. Methods. Human umbilical vein endothelial cells (HUVECs) were cultured on biaxial stretch silicon membranes at 8% stretch and 60 cycles/min for 2 days. The mRNA levels of two smooth muscle cell (SMC) markers (α-actin and SM22-α) as well as a house keeping gene (GAPDH) were quantitatively determined by real-time RT-PCR. The data present as the difference of reaction cycle thresholds (CT) between GAPDH and each of other genes (2 - Δ C T ). Results. The mRNA levels of specific SMC α-actin and actin binding protein SM22-α were significantly increased by 5- and 2-fold, respectively, in cyclic strain treated HUVECs (0.255 +/- 0.05 and 0.282 +/- 0.004, respectively) as compared to those in untreated cells (0.042 +/- 0.02 and 0.089 +/- 0.023, respectively) (P < 0.05). Conclusion. These data demonstrate that cyclic strain significantly induces expression of two specific SMC markers in HUVECs. This study suggests that homodynamic factors may induce potential transdifferentiation from endothelial cells to smooth muscle cells.