Hydrophilic Monomethyl Auristatin E Derivatives as Novel Candidates for the Design of Antibody-Drug Conjugates

Abstract

Antibody-drug conjugates (ADCs) are promising state-of-the-art biopharmaceutical drugs for selective drug-delivery applications and the treatment of diseases such as cancer. The idea behind the ADC technology is remarkable as it combines the highly selective targeting capacity of monoclonal antibodies with the cancer-killing ability of potent cytotoxic agents. The continuous development of improved ADCs requires systematic studies on the nature and effects of warhead modification. Recently, we focused on the hydrophilic modification of monomethyl auristatin E (MMAE), the most widely used cytotoxic agent in current clinical trial ADCs. Herein, we report on the use of micellar electrokinetic chromatography (MEKC) for studying the hydrophobic character of modified MMAE derivatives. Our data reveal a connection between the hydrophobicity of the modified warheads as free molecules and their cytotoxic activity. In addition, MMAE-trastuzumab ADCs were constructed and evaluated in preliminary cytotoxic assays.

Site-Specific, Stoichiometric-Controlled, PEGylated Conjugates of Fibroblast Growth Factor 2 (FGF2) with Hydrophilic Auristatin Y for Highly Selective Killing of Cancer Cells Overproducing Fibroblast Growth Factor Receptor 1 (FGFR1)

“…Importantly, the FGF2 3xC -(tvAY) 3 conjugate was nontoxic to FGFR1-negative cell lines ( Figure 7 , Table 2 ). Finally, in agreement with ADC data, 20 , 22 , 65 the therapeutic index was increased due to the hydrophilic nature of the (tvAY) 3 payload.…”

“… 36 However, there are numerous chemical derivatives of auristatin, i.e., MMAE, MMAF, MMAU, and AY, which differ in hydrophobicity, charge, and cytotoxicity. 20 , 22 , 39 , 69 Taking into account the plan to load FGF2 with three auristatin molecules, we decided to use more hydrophilic AY. Unlike MMAE, 39 AY did not show toxicity as a free drug ( Figure 7 , Table 2 ).…”

“… 28 − 32 Other strategies utilize glucuronidation of the cytotoxic agent or preparation of its hydrophilic derivatives. 20 , 22 , 33 , 34 …”

Assessing the Interactions of Auristatin Derivatives with Mixed Phospholipid–Sodium Dodecyl Sulfate Aggregate Dispersions

“…The order was similar to that for structural analogues 2 and 3 , while structure 1 had the strongest distribution into SDS micelles. Compound 1 has the lowest theoretical distribution coefficient (log D values at pH 7.4 were 2.0, −0.43, 1.1, and 1.3 for MMAE, 1 , 2 , and 3 , respectively), 7 being the least lipophilic compound. In our previous study, 7 SDS was shown to have poor selectivity toward the auristatin derivatives as a result of their nearly complete solubilization into the SDS micelles.…”

“…Compound 1 has the lowest theoretical distribution coefficient (log D values at pH 7.4 were 2.0, −0.43, 1.1, and 1.3 for MMAE, 1 , 2 , and 3 , respectively), 7 being the least lipophilic compound. In our previous study, 7 SDS was shown to have poor selectivity toward the auristatin derivatives as a result of their nearly complete solubilization into the SDS micelles. SDS micelles are stronger hydrogen bond donors than 1-octanol; therefore, they are expected to have strong interactions with hydrogen bond acceptor solutes 42 such as MMAE and its derivatives.…”