MT-12 inhibits the growth and metastasis of bladder cancer cells via suppressing tumor angiogenesis in vivo and in vitro

BACKGROUND: Cobra venom membrane toxin (MT) has been defined as a major subset of cobra venom having cardiac toxicity and anticancer activity properties. In our previous study, cobra venom membrane toxin 12 (MT-12), isolated from the snake venom of Chinese Naja naja atra, was confirmed to selectively suppress the proliferation and invasion of the bladder cancer (BC) cell line EJ. However, the results have never been confirmed in other bladder cell lines, and the underlying mechanism by which MT-12 inhibits BC is still unknown. Thus, in this study, the effect of MT-12 on the proliferation, adhesion, and invasion of BC cells was explored in vitro and in vivo. As tumor angiogenesis is a prerequisite for tumor growth and metastasis, the factors involved, such as matrix metalloproteinases (MMPs), vascular endothelial growth factor (VEGF), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1), were tested in our study. METHODS: Using RT4 and T24 cells for experiments, CCK-8 assays were used to determine cell proliferation. Annexin V-FITC/PI was used to determine cell apoptosis status. Wound-healing assays were used to determine cell invasion. Cell adhesion experiments were used to determine cell adhesion. Gelatin zymography was used to determine the enzymatic activity of MMP-9 and MMP-2. RT-PCR, ELISA, and immunohistochemistry were used to determine the expression of VEGF, ICAM-1, and VCAM-1. RESULTS: MT-12 inhibited proliferation, invasion, and adhesion and promoted cell apoptosis in RT4 and T24 cells; this anticancer effect was concentration-dependent. In the BC xenograft mouse model, the results revealed that MT-12 might decrease tumor growth and weight. MT-12 was shown to have an inhibitory effect on MMP-9 activation and the expression of VEGF and ICAM-1 in BC cells in vitro and in vivo. CONCLUSIONS: The results of the present study, suggest that MT-12 could effectively inhibit BC cell growth and metastasis via inhibition of tumor angiogenesis. As a result, MT-12 may become a novel drug for BC.