monomethyl-auristatin-e and Carcinoma--Pancreatic-Ductal

Aberrant expression of the RON receptor tyrosine kinase is a pathogenic feature and a validated drug target in various types of cancers. Currently, therapeutic antibodies targeting RON for cancer therapy are under intensive evaluation. Here we report the development and validation of a novel humanized anti-RON antibody-drug conjugate for cancer therapy.. Antibody humanization was achieved by grafting sequences of complementarity-determining regions from mouse monoclonal antibody Zt/g4 into human IgG1/κ acceptor frameworks. The selected humanized Zt/g4 subclone H1L3 was conjugated with monomethyl auristatin E using a dipeptide linker to form H-Zt/g4-MMAE. Pharmacokinetic analysis of H-Zt/g4-MMAE was determined using hydrophobic interaction chromatography and a MMAE ADC ELISA kit. Biochemical and biological assays were used for measuring RON expression, internalization, cell viability and death. Therapeutic efficacies of H-Zt/g4-MMAE were validated in vivo using three pancreatic cancer xenograft models. Toxicological activities of H-Zt/g4-MMAE were determined in mouse and cynomolgus monkey.. H-Zt/g4-MMAE is superior in eradication of pancreatic cancer xenografts with favorable pharmacokinetic profiles and manageable toxicological activities. These findings warrant the transition of H-Zt/g4-MMAE into clinical trials in the future.

Topics: Animals; Antibodies, Monoclonal, Humanized; Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Cell Proliferation; Cell Survival; Female; Gene Expression Regulation, Neoplastic; HCT116 Cells; HT29 Cells; Humans; Immunoconjugates; Macaca fascicularis; Mice; NIH 3T3 Cells; Oligopeptides; Pancreatic Neoplasms; Receptor Protein-Tyrosine Kinases; Xenograft Model Antitumor Assays

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer characterized by poor response to chemotherapy and radiotherapy due to the lack of efficient therapeutic tools and early diagnostic markers. We previously generated the nonligand competing anti-HER3 antibody 9F7-F11 that binds to pancreatic tumor cells and induces tumor regression in vivo in experimental models. Here, we asked whether coupling 9F7-F11 with a radiosensitizer, such as monomethylauristatin E (MMAE), by using the antibody-drug conjugate (ADC) technology could improve radiation therapy efficacy in PDAC. We found that the MMAE-based HER3 antibody-drug conjugate (HER3-ADC) was efficiently internalized in tumor cells, increased the fraction of cells arrested in G2/M, which is the most radiosensitive phase of the cell cycle, and promoted programmed cell death of irradiated HER3-positive pancreatic cancer cells (BxPC3 and HPAC cell lines). HER3-ADC decreased the clonogenic survival of irradiated cells by increasing DNA double-strand break formation (based on γH2AX level), and by modulating DNA damage repair. Tumor radiosensitization with HER3-ADC favored the inhibition of the AKT-induced survival pathway, together with more efficient caspase 3/PARP-mediated apoptosis. Incubation with HER3-ADC before irradiation synergistically reduced the phosphorylation of STAT3, which is involved in chemoradiation resistance. In vivo, the combination of HER3-ADC with radiation therapy increased the overall survival of mice harboring BxPC3, HPAC cell xenografts or patient-derived xenografts, and reduced proliferation (KI67-positive cells). Combining auristatin radiosensitizer delivery via an HER3-ADC with radiotherapy is a new promising therapeutic strategy in PDAC.

Topics: Animals; Antibodies, Monoclonal, Murine-Derived; Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chemoradiotherapy; Humans; Immunoconjugates; Immunologic Factors; Mice; Oligopeptides; Pancreatic Neoplasms; Phosphorylation; STAT3 Transcription Factor; Treatment Outcome; Xenograft Model Antitumor Assays