Novel Fusion Protein Based on DR5-Specific TRAIL Variant with Enhanced Antitumor Properties

The cytokine TRAIL is distinguished by its remarkable ability to preferentially induce apoptosis in transformed, but not in normal, cells. The recombinant TRAIL extracellular domain and other first-generation agonists of DR4 and DR5 death receptors (DRs) have shown very limited antitumor activity in clinical trials. To enhance the antitumor effect, we developed the multitarget recombinant fusion protein SRH-DR5-B-p48 based on the DR5-selective TRAIL variant DR5-B to simultaneously affect tumor cells (DR5-B-mediated apoptosis) and tumor microenvironment, in particular, to suppress angiogenesis. For this purpose, we modeled and produced the recombinant SRH-DR5-B-p48 fusion protein containing antagonistic synthetic peptides (SRH and p48) to VEGFR2 and FGFR1 receptors, respectively. Analysis of molecular trajectories using molecular dynamics methods showed that the SRH and p48 peptides form non-specific temporary contacts with the DR5-B domain. Using enzyme-linked immunosorbent assay, we showed that SRH-DR5-B-p48 was similar to DR5-B in its affinity for the death receptor DR5 and demonstrated a high affinity for VEGFR2 and FGFR1 with nanomolar dissociation constants. SRH-DR5-B-p48 killed tumor cells of various origin more efficiently than DR5-B and destroyed tumor-like structures in 3D cell models, as well as inhibited FGF2-mediated stimulation of fibroblast proliferation. Therefore, the SRH-DR5-B-p48 fusion protein can be considered as a promising agent for the therapy of solid tumors of various origin.