VHH212 nanobody targeting the hypoxia-inducible factor 1α suppresses angiogenesis and potentiates gemcitabine therapy in pancreatic cancer in vivo

Objective: We aimed to develop a novel anti-HIF-1 alpha intrabody to decrease gemcitabine resistance in pancreatic cancer patients. Methods: Surface plasmon resonance and glutathione S-transferase pull-down assays were conducted to identify the binding affinity and specificity of anti-HIF-1 alpha VHH212 [a single-domain antibody (nanobody)]. Molecular dynamics simulation was used to determine the protein-protein interactions between hypoxia-inducible factor-1 alpha (HIF-1 alpha) and VHH212. The real-time polymerase chain reaction (PCR) and Western blot analyses were performed to identify the expressions of HIF-1 alpha and VEGF-A in pancreatic ductal adenocarcinoma cell lines. The efficiency of the VHH212 nanobody in inhibiting the HIF-1 signaling pathway was measured using a dual-luciferase reporter assay. Finally, a PANC-1 xenograft model was developed to evaluate the anti-tumor efficiency of combined treatment. Immunohistochemistry analysis was conducted to detect the expressions of HIF-1 alpha and VEGF-A in tumor tissues. Results: VHH212 was stably expressed in tumor cells with low cytotoxicity, high affinity, specific subcellular localization, and neutralization of HIF-1 alpha in the cytoplasm or nucleus. The binding affinity between VHH212 and the HIF-1 alpha PAS-B domain was 42.7 nM. Intrabody competitive inhibition of the HIF-1 alpha heterodimer with an aryl hydrocarbon receptor nuclear translocator was used to inhibit the HIF-1/VEGF pathway in vitro. Compared with single agent gemcitabine, co-treatment with gemcitabine and a VHH212-encoding adenovirus significantly suppressed tumor growth in the xenograft model with 80.44% tumor inhibition. Conclusions: We developed an anti-HIF-1 alpha nanobody and showed the function of VHH212 in a preclinical murine model of PANC-1 pancreatic cancer. The combination of VHH212 and gemcitabine significantly inhibited tumor development. These results suggested that combined use of anti-HIF-1 alpha nanobodies with first-line treatment may in the future be an effective treatment for pancreatic cancer.

Automated summary

A novel anti-HIF-1 alpha nanobody, VHH212, was developed to reduce gemcitabine resistance in pancreatic cancer patients. Combination therapy with a VHH212-encoding adenovirus and gemcitabine significantly suppressed tumor growth in a xenograft model of PANC-1 pancreatic cancer, showing potential as an effective treatment for pancreatic cancer.