Preclinical Efficacy of Anti-RON Antibody–Drug Conjugate Zt/g4-MMAE for Targeted Therapy of Pancreatic Cancer Overexpressing RON Receptor Tyrosine Kinase

Abstract

Aberrant expression of the RON receptor tyrosine kinase, a cell surface protein, is a pathogenic feature in pancreatic cancer, which renders it a drug target for targeted therapy. Nevertheless, development of therapeutics targeting RON for pancreatic cancer therapy is hampered due to the lack of full addiction by pancreatic cancer cells to RON signaling for growth and survival. Here we describe a novel strategy using anti-RON antibody-directed drug delivery in the form of an antibody-drug conjugate for inhibition and/or eradication of pancreatic cancers. Monoclonal antibody Zt/g4 specific to the RON Sema domain was selected as the drug carrier based on its ability to induce robust RON internalization. Conjugation of Zt/g4 with monomethyl auristatin E, designated as Zt/g4-MMAE, was achieved through a protease-sensitive dipeptide linker to reach a drug to antibody ratio of 3.29:1. Zt/g4-MMAE was stable in human plasma with a dissociation rate less than 4% within a 10 day period. In vitro, Zt/g4-MMAE rapidly induced RON internalization, resulting in cell cycle arrest followed by massive cell death. The maximal effect was seen in pancreatic cancer cells with more than 10 000 receptor molecules per cell. Zt/g4-MMAE also synergized in vitro with chemotherapeutics including gemcitabine, 5-fluorouracil, and oxaliplatin to further reduce PDAC cell viability. In vivo, Zt/g4-MMAE exerts a long-lasting activity, which not only inhibited but also eradicated pancreatic xenograft tumors. These finding indicate that Zt/g4-directed drug delivery is highly effective for eradicating pancreatic tumors. Thus, Zt/g4-MMAE is a novel biotherapeutic with potential for therapy of RON-expressing pancreatic malignancies.

Therapeutic efficacy, pharmacokinetic profiles, and toxicological activities of humanized antibody-drug conjugate Zt/g4-MMAE targeting RON receptor tyrosine kinase for cancer therapy

“…However, the effect of Zt/g4-DM1 on pancreatic xenograft tumors is relatively weak [30]. To improve the efficacy for Zt/g4-based ADCs, we conjugated Zt/g4 with monomethyl auristatin E (MMAE) to generate Zt/g4-MMAE using a protease-sensitive dipeptide linker [31, 32]. Studies in vivo confirmed that Zt/g4-MMAE is highly potent in inhibition and/or eradication of xenograft tumors initiated by PDAC cells [32], which is insensitive to Zt/g4-DM1 [30].…”

Receptor tyrosine kinase, RON, promotes tumor progression by regulating EMT and the MAPK signaling pathway in human oral squamous cell carcinoma

“…The phase I/II clinical trials of the tyrosine kinase inhibitor, foretinib, multi-targeting c-Met, vascular endothelial growth factor 2 and RON, and anti-RON monoclonal antibody, narnatumab, have reported for advanced solid tumors, although the clinical trials were abandoned (21,(41)(42)(43). Several studies recently reported that the anti-RON antibody Zt/g4-drug conjugate (ADC) is effective in targeted inhibition of colorectal cancer, bladder cancer, triple-negative breast cancer and pancreatic cancer (44)(45)(46)(47). In addition, Ruiz-Torres et al (48) demonstrated that the RON signaling pathway is associated with the immunosuppressive microenvironment in breast cancer.…”

The Novel Anti-cMet Antibody seeMet 12 Potentiates Sorafenib Therapy and Radiotherapy in a Colorectal Cancer Model

“…Combination effects of seeMet 12 and sorafenib, and seeMet 12 and radiotherapy in clonogenic survival assays were analyzed by the Chou-Talalay-method by the software CompuSyn 3 developed by Nick Martin of MIT, Cambridge, MA, United States. The combination index (CI) and fraction affected (Fa) was calculated and operates as the percent growth inhibition ( 27 ). A CI of ≤0.8 indicates synergism, CI ≥ 1.2 antagonism.…”