Mechanism of anti-CXCR4 nanobody inhibiting angiogenesis in pancreatic cancer

Tumor angiogenesis provides adequate oxygen and nutrition for tumor development and supports tumor growth and metastasis. Stromal cell derived factor 1 (SDF-1) and its receptor C-X-C motif chemokine receptor 4 (CXCR4) in pancreatic cancer microenvironment are involved in tumor growth such as promoting tumor cell proliferation, migration, and angiogenesis. In this study, anti-CXCR4 nanobody (CXCR4 Nb) and anti-programmed cell death ligand 1 (PD-L1) & CXCR4 bispecific nanobody (PX4 BsNb) were expressed in Escherichia coli system and purified by nickel column affinity chromatography. We investigated the anti-angiogenesis activity and mechanism of CXCR4 Nb by in vivo and in vitro experiments. Ethical approval was obtained for collection of human peripheral blood mononuclear cell (hPBMC) samples from the Local Ethics Committee of Shanghai Jiao Tong University. All animal experiments were approved by the Animal Ethic Committee of Shanghai Jiao Tong University. The results showed that CXCR4 Nb at 0.1 μmol·L^-1 could effectively inhibit the proliferation and migration of human umbilical vein endothelial cells (HUVEC) promoted by pancreatic stellate cells in vitro. CXCR4 Nb and PX4 BsNb at 0.3 mg·kg^-1 obviously decreased tumor angiogenesis and inhibited the tumor growth in NOD/SCID mice, the inhibitory rates were 28.8% and 36.1%, respectively. CXCR4 Nb significantly inhibited tumor growth and angiogenesis with great safety, which provides support for application of CXCR4 Nb and anti-angiogenesis therapy of pancreatic cancer.