Objectives: To determine the prognostic role of vasculogenic mimicry in adrenocortical carcinoma, and to explore its relationship with vascular endothelial growth factor receptor 2 expression.
Methods: A total of 46 samples of adrenocortical carcinoma were collected and reviewed. Vasculogenic mimicry and vascular endothelial growth factor receptor 2 were detected by immunohistochemistry and double staining. Survival analysis was carried out to access pronostic significance. Three-dimensional culture method was applied to test the ability of vasculogenic mimicry formation by adrenocortical carcinoma cell lines SW-13 and H295R. Quantitative polymerase chain reaction and western blotting were used to monitor the expression of vascular endothelial growth factor receptor 2 in SW-13 and H295R. After being treated with specific inhibitor or small interfering ribonucleic acid to downregulate expression of vascular endothelial growth factor receptor 2, vasculogenic mimicry formation and cell prolifration of SW-13 cells were evaluated by 3-D culture and Cell Counting Kit-8 methods.
Results: Vasculogenic mimicry was observed in 19 of the 46 (41.30%) adrenocortical carcinoma samples. Both vasculogenic mimicry and vascular endothelial growth factor receptor 2 expressions showed a positive association with Weiss score and TNM stage, whereas vascular endothelial growth factor receptor 2 was also associated with tumor size (all P < 0.05). Vasculogenic mimicry was closely correlated with vascular endothelial growth factor receptor 2 expressions (r = 0.470, P < 0.01). The median overall survival of patients with vasculogenicmimicry-positive or vascular endothelial growth factor receptor 2-positive was shorter than that of patients with vasculogenic mimicry-negative or vascular endothelial growth factor receptor 2-negative (P = 0.001 and 0.028, respectively). The vasculogenic mimicry-forming SW-13 cells expressed higher levels of vascular endothelial growth factor receptor 2 than that of H295R, which was unable to form vasculogenic mimicry on Matrigel. However, downregulation of vascular endothelial growth factor receptor 2 only decreased cell proliferation, but not vasculogenic mimicry formation by SW-13 cells.
Conclusions: Vasculogenic mimicry and overexpression of vascular endothelial growth factor receptor 2 seem to correlate with poor prognostic outcomes in adrenocortical carcinoma. Anti-angiogenesis treatments targeting vascular endothelial growth factor receptor 2 should be combined with therapies targeting vasculogenic mimicry in adrenocortical carcinoma.
Keywords: adrenocortical carcinoma; anti-angiogenesis therapy; mitotane; vascular endothelial growth factor receptor 2; vasculogenic mimicry.
© 2016 The Japanese Urological Association.