Engineered scPDL1-DM1 drug conjugate with improved in vitro analysis to target PD-L1 positive cancer cells and intracellular trafficking studies in cancer therapy.

Muhammad Kalim,Jinbiao Zhan,Keying Liang,Muhammad Saleem Iqbal Khan,Shenghao Wang

doi:10.1590/1678-4685-gmb-2018-0391

Abstract

Antibody-drug conjugates (ADC), precisely deliver a cytotoxic agent to antigen-expressing tumor cells by using specific binding strategies of antibodies. The ADC has shown the ability of potent bio-therapeutics development but indefinite stoichiometric linkage and full-length antibody penetration compromised the field of its advancement. Single chain variable fragments convention instead of the full-length antibody may overcome the challenge of rapid penetration and internalization. Programmed cell death ligand-1 interaction with PD-1 has recently revolutionized the field of immunotherapy. We systematically designed scPDL1-DM1 drug conjugate by linking scFv-PD-L1 proteins (scFv) with maytansinoids (DM1) cytotoxic agent through succinimidyl trans-4-maleimidylmethyl cyclohexane-1- carboxylate (SMCC) linker. Binding affinity was confirmed by immunocytochemistry, spectrophotometry and gel electrophoresis analysis. The scPDL1-DM1 showed specific binding with PD-L1 positive tumor cells and retained in vitro anti-cell proliferation activity. The intracellular trafficking of the drug was evaluated in A549 cancer cell lines, and maximum trafficking was observed after two hours of incubation. The generated drug can be utilized as a potent tool for site-specific conjugation, predicting specificity in vitro activities with extended range against PD-L1 positive cancer cells and can be utilized for further in vivo testing and clinical therapeutics development.

Highlights

Targeted chemotherapy surges discerning the delivery of toxic drugs to tumor cells by conjugating them with monoclonal antibodies
We have reported the generation of scFv-programmed cell death ligands- 1 (PD-L1) proteins (scFv)-PD-L1 drug conjugate and in vitro activity analysis against different cancer cell lines
Antibody-drug conjugates were designed with maytansinoids (DM1) cytotoxic agent through succinimidyl trans-4-maleimidylmethyl cyclohexane-1- carboxylate (SMCC) thioether linker for active release of drug by intracellular reduction

Summary

Introduction

Targeted chemotherapy surges discerning the delivery of toxic drugs to tumor cells by conjugating them with monoclonal antibodies (mAbs). Antibody monotherapy often lacks elevated therapeutic index and limits immune induction, alternatively, antibodies can be joined with cytotoxic drugs to efficiently reduce systematic toxicity and enhance targeted delivery to tumor cells (Dal Corso et al, 2018). Lysine and cysteine sulfhydryl chains help in the conjugation of drugs to antibodies by reducing disulfide bonds in the development of antibody-drug conjugates (ADC). This heterogeneity facilitates binding of 2, 4 and 8 drug residues to targeted antibody and was reported in vivo potency in mice model. Several studies indicate that engineered antibody can be utilized to exploit the endosomal pathways that provide a substantial clove for future studies and better designing of ADC (Kalim et al, 2017)

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Conclusion