Biological evaluation of antibody-maytansinoid conjugates as a strategy of RON targeted drug delivery for treatment of non-small cell lung cancer.
BACKGROUND
Aberrant expression of the RON receptor tyrosine kinase, a member of the MET proto-oncogene family, in breast cancer and non-small cell lung cancer (NSCLC) has therapeutic implication. Here we evaluated the efficacy of a novel anti-RON antibody-drug maytansinoid conjugate Zt/g4-DM1 for treatment of breast and NSCLC xenograft tumors in mouse models and explored a treatment strategy by combination of Zt/g4-DM1 with chemotherapeutics to achieve the maximal therapeutic activity.


METHODS
Mouse monoclonal antibody Zt/g4 (IgG1a/κ) specific to human RON was conjugated to DM1 via thioether linkage to form Zt/g4-DM1 with a drug-antibody ratio of 4:1. Several breast cancer and NSCLC cell lines, expressing different levels of RON, were used as the model. Immunofluorescence was used to determine Zt/g4-induced RON internalization. Flow cytometric analysis and cell viability assay were used to determine the effect of Zt-g4-DM1 on cell cycle and death. Mouse xenograft NSCLC models were used in vivo to determine the therapeutic efficacy of Zt/g4-DM1 alone or in combination with chemotherapeutics.


RESULTS
In vitro, Zt/g4 treatment of breast cancer and NSCLC cells rapidly induced cell surface RON internalization, which results in intracellular delivery of DM1 sufficient to arrest cell cycle at G2/M phase, reduce cell viability, and cause massive cell death. In mouse tumor xenograft models, Zt/g4-DM1 at 20 mg/kg in a Q12 × 2 regimen effectively blocked breast cancer and NSCLC cell- mediated tumor growth. More than 95% inhibition of tumor growth among three tumor xenograft models tested was achieved according to the measured tumor volume. The minimal dose to balance the tumor growth and inhibition (tumoristatic concentration) was established at 2.02 mg/kg for H2228, 1.94 mg/kg for H358 cell, and 6.25 mg/kg for T-47D cell-mediated xenograft tumors.


CONCLUSIONS
Zt/g4 is highly effective in RON-directed drug delivery for targeted inhibition of NSCLC cell-derived tumor growth in mouse xenograft models. This work provides the basis for clinical development of humanized Zt/g4-DM1 for potential cancer therapy in the future.
State Key Laboratory for Diagnosis & Treatment of Infectious Diseases and Collaborative Innovation Center for Diagnosis & Treatment of Infectious Diseases, First Hospital of Zhejiang University School of Medicine, Zhejiang, China.|Department of Biomedical Sciences, Texas Tech University Health Sciences Center School of Pharmacy, 1406 Coulter Street, Suite 1117, Amarillo, TX, 79106, USA.
Liang
L
Feng
State Key Laboratory for Diagnosis & Treatment of Infectious Diseases and Collaborative Innovation Center for Diagnosis & Treatment of Infectious Diseases, First Hospital of Zhejiang University School of Medicine, Zhejiang, China.|Department of Biomedical Sciences, Texas Tech University Health Sciences Center School of Pharmacy, 1406 Coulter Street, Suite 1117, Amarillo, TX, 79106, USA.
Hang-Ping
HP
Yao
Department of Neurosurgery, First Hospital of Zhejiang University School of Medicine, Zhejiang, China.
Yong-Qing
YQ
Zhou
Department of Molecular Cell Biology & Toxicology, Nanjing Medical University School of Public Health, Jiangsu, China.
Jianwei
J
Zhou
Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center School of Pharmacy, Amarillo, TX, USA.
Ruiwen
R
Zhang
State Key Laboratory for Diagnosis & Treatment of Infectious Diseases and Collaborative Innovation Center for Diagnosis & Treatment of Infectious Diseases, First Hospital of Zhejiang University School of Medicine, Zhejiang, China. minghai.wang@ttuhsc.edu.|Department of Biomedical Sciences, Texas Tech University Health Sciences Center School of Pharmacy, 1406 Coulter Street, Suite 1117, Amarillo, TX, 79106, USA. minghai.wang@ttuhsc.edu.
Ming-Hai
MH
Wang
D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage* / Q000494:pharmacology / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy*; D008453:Maytansine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D051379:Mice; D058990:Molecular Targeted Therapy / Q000379:methods*; D000090063:Proto-Oncogene Mas; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
D000911:Antibodies, Monoclonal; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; C562224:maytansinol; D008453:Maytansine; C080835:RON protein; D020794:Receptor Protein-Tyrosine Kinases
Antibody-drug conjugate; Breast cancer; Combination therapy; Lung cancer; Receptor tyrosine kinase; Therapeutic efficacy