Norcantharidin enhances TIMP‑2 anti‑vasculogenic mimicry activity for human gallbladder cancers through downregulating MMP‑2 and MT1‑MMP

: Vasculogenic mimicry (VM) is a tumor microcirculation pattern in highly aggressive gallbladder cancers (GBCs). We recently reported the anti‑VM activity of norcantharidin (NCTD) in highly aggressive GBC‑SD cells and xenografts. In this study, we further investigated that NCTD enhanced tissue inhibitor of matrix metalloproteinase‑2 (TIMP‑2) anti‑VM activity for GBCs and the underlying mechanisms. In vivo and in vitro experiments were performed to determine the effects of NCTD in combination with TIMP‑2 on tumor growth, host survival, VM formation, hemodynamic of GBC‑SD xenografts, and VM‑like networks and malignant phenotypes of GBC‑SD cells. Expression of matrix metalloproteinase (MMP)‑2 and membrane type 1‑MMP (MT1‑MMP) among human GBCs, GBC‑SD cells and xenografts were determined, respectively. The results showed that expression of MMP‑2 and MT1‑MMP in human GBCs, GBC‑SD cells and xenografts was significantly related to VM in GBCs; a shorter survival time of VM‑positive patients with high expression of MMP‑2 or MT1‑MMP compared to that of the patients with low expression. After treatment with NCTD+TIMP‑2, tumor growth, VM formation, VM hemodynamic of the xenografts in vivo were significantly inhibited as compared to control, NCTD or TIMP‑2 group, with a prolonged survival time of the xenograft mice (log‑rank test, P=0.0115); and these observations were confirmed by VM‑like networks by 3‑D matrices and showed that proliferation, apoptosis, invasion, migration of GBC‑SD cells in vitro were markedly affected. Furthermore, expression of MMP‑2 and MT1‑MMP in VM formation of the xenografts in vivo and GBC‑SD cells in vitro was downregulated as compared to control, NCTD or TIMP‑2 group. Thus, we concluded that NCTD enhances TIMP‑2 antitumor and anti‑VM activities in GBCs through downregulating MMP‑2 and MT1‑MMP.