Supplementary Figures from A New Triglycyl Peptide Linker for Antibody–Drug Conjugates (ADCs) with Improved Targeted Killing of Cancer Cells

Abstract

<p>Supplementary Figures (S1-S4). Supplementary Figure S1: In vitro cytotoxic activities of tetraglycyl (Gly4), triglycyl (Gly3), diglycyl (Gly2), and valine-citrulline-glycine (VCG)-linked anti-EGFR ADCs and a triglycyl-linked non-binding antibody ADC in PC-9, Ca9-22, HSC-2, H1975, A-431, and OSC-19 cells (3-4 DAR ADCs). Supplementary Figure S2: In vitro cytotoxic activities of anti-EpCAM CX and SMCC ADCs toward a low EpCAM antigen-expressing cell line, RPMI 8226 (~50,000 EpCAM per cell). The CX ADCs tested included a conjugate with a typical payload number (3.9 maytansinoid molecules per antibody molecule; 3.9 DAR) and conjugates with high payload numbers (8 and 9.6 DAR). The SMCC ADC had a typical payload number (4.3 DAR). Supplementary Figure S3: Binding-competition ELISA of catabolites of CX ADC (DM-CX1 and DM-CX2) and SMCC ADC (lysine-SMCC-DM1): inhibition by catabolites toward binding of anti-maytansine antibody to immobilized BSA-maytansinoid conjugate. Supplementary Figure S4: Test of bystander cytotoxic activity of anti-EGFR-CX-DM1 or SPDB-DM4 conjugate in mixed culture of EGFR-positive (Ca9-22) and EGFR-negative (Ramos) cells.</p>