Figure 3. ES cells are affected in vitro by ENG-ADCs treatment within an ENG expression-dependent manner.

(A) OMTX003 was tested on three ES cell lines: RM82, TC71 and CADO, which show differential expression of ENG, in order to evaluate in vitro the effect of this ADC on the proliferation rate of these cell lines. (B) Chemical structure of the OMTX-ADC, ENG MAb candidate lead linked to a cytotoxic agent, nigrin-b A chain (OMTX503) or cytolysin (OMTX703). (C) OMTX503 activity was tested on these cell lines, which resulted in an inhibition of their proliferation rate in an ENG expression-dependent manner. (D) There is a significant correlation between the IC₅₀ of OMTX503 over the ES cell lines RM82, TC71 and CADO and the ENG protein expression of these cell lines (r = −0.9999, p = 0.0082). (E) OMTX003 and OMTX703 were tested during 72 h in WST1 proliferation cell-based assay using ES8 cell line. Only OMTX703 showed a significant inhibition of ES8 cell proliferation in a dose-dependent manner (IC₅₀ = 260 nM).