Intratumoral injection of pEGFC1-IGFBP7 inhibits malignant melanoma growth in C57BL/6J mice by inducing apoptosis and down-regulating VEGF expression

Malignant melanoma (MM) is a type of aggressive skin cancer, and the effective therapy for MM is highly desired. Recently, genome-wide RNA interference screening study revealed that loss of expression of insulin-like growth factor binding protein 7 (IGFBP-7) is a critical step in development of MM, and this secreted protein plays a central role in apoptosis of MM. Furthermore, a prostatic carcinoma cell line stably transfected with IGFBP-7 cDNA showed poor tumorigenicity. Thus, we supposed it to be an efficacious agent for inhibiting melanomas. In this study, we constructed pEGFC1-IGFBP7 to try to obtain high expression of IGFPB7 and then we demonstrated that this plasmid inhibited proliferation of B16-F10 melanoma cells efficiently in vitro. Moreover, intratumoral injection of pEGFC1-IGFBP7 inhibited MM growth in C57BL/6J mice. The inhibition of MM growth is due to apoptosis and reduced expression of VEGF induced by pEGFC1-IGFBP7. These results suggest a potential new clinical strategy for MM treatment.