Abstract
Current therapies available for the treatment of human osteosarcoma, an aggressive bone tumor, are insufficient. To examine an alternative approach of integrin-based anti-osteosacoma strategy, acurhagin-C, a Glu-Cys-Asp (ECD)-disintegrin, was isolated and evaluated for its application in combination with two potent inhibitors of basic fibroblast growth factor (bFGF) and interleukin-8 (IL-8). The investigation of human osteosarcoma MG-63 cells pre-incubated with a FGF receptor-1 (FGFR-1) blocker AZD4547, a CXC-chemokine receptor-1/-2 (CXCR1/2) antagonist reparixin, and acurhagin-C via two given modes of separation and combination was executed. Detected by flow cytometry, integrins-α2/-α5/-αv/-β1, FGFR-1, CXCR1 and CXCR2 constitutively express on the resting membrane. However, bFGF/IL-8-activated MG-63 cells only statistically enhanced the surface exposure of integrins-α5/-β1, FGFR-1 and CXCR2. In activated MG-63 cells, acurhagin-C targeting integrin-α5 not only might potentiate the inhibitory effect of AZD4547 and reparixin on the surface expression of integrin-α5, FGFR-1 and CXCR2, but also acurhagin-C used alone remained effectively to diminish the surface exposure of those targeted receptors. Hence, a complicated crosstalk mechanism should be involved in the membrane interactions. Furthermore, co-administration of acurhagin-C with AZD4547 and reparixin also showed to have the synergistic suppression toward cell proliferation and the gene expression of matrix metalloproteinase-2. Also, the administration of three-in-one mode could nearly abrogate the cellular attachment onto collagen-IV- and fibronectin-coated wells, as well as penetration into Matrigel-barrier. These data supported an ECD-disintegrin acurhagin-C targeting integrin-α5 upon combined used with AZD4547 and reparixin may become a promising therapeutic approach for attenuating osteosarcoma development.