Simultaneous targeting of VEGF message and VEGF receptor signaling as a therapeutic anticancer approach

Background: Vascular endothelial growth factor (VEGF) is one of the most important factors involved in tumor angiogenesis. Materials and Methods: Antisense phosphorothiolate oligodeoxynucleotides (PS-ODNs) were used to reduce VEGF production while the small molecule PD0203359-0002 (PD203359) was used to inhibit VEGF/bFGF receptor tyrosine kinase activity. Results: PD203359 exposure was found to profoundly impair the growth of human endothelial cells (HMVEC-L) at doses 20-fold less than those affecting human renal cell carcinoma (Caki-1) cell growth. In vivo, treatment with PD203359 inhibited tumor cell-induced angiogenesis and resulted in a significant tumor growth delay. Treatment with VEGF antisense PS-ODNs also significantly increased the time for tumors to grow to five times the starting size. Most importantly, when the PD203359 and VEGF antisense treatments were combined, a greater antitumor response than could be achieved with either therapy alone was observed. Conclusion: Simultaneously targeting VEGF production and VEGF receptor signaling enhances the anticancer efficacy of either therapy alone.