Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
School of Pharmacy, University of Otago, Dunedin, 9054, New Zealand.
Eur J Med Chem. 2022 Mar 15;232:114172. doi: 10.1016/j.ejmech.2022.114172. Epub 2022 Feb 3.
Tissue transglutaminase (TG2) is a multifunctional protein that catalyses protein crosslinking in the extracellular matrix, and functions as an intracellular G-protein. While both activities have been associated with human diseases, its role as a G-protein has been linked to cancer stem cell survival and maintenance of a metastatic phenotype. Recently we have shown that targeted covalent inhibitors (TCIs) can react selectively with the enzyme active site of TG2, to allosterically abolish its ability to bind GTP. In the present work, we focused on the variation of the N-terminal group of these peptidomimetic inhibitors, in order to enhance efficiency, while reducing log P and the number of rotatable bonds. This approach led to the synthesis and evaluation of 41 novel inhibitors, some of which had greatly improved efficiency and affinity for TG2 (e.g. TCI 72: K = 1.0 μM, k/K = 4.4 × 10 M min). Molecular modelling provided a hypothetical binding mode for these TCIs. The most efficient inhibitors were evaluated further and shown to have excellent isozyme selectivity, to block GTP binding, and to have improved pharmacokinetic properties, as expected. Their biological activity was also confirmed, in a cellular invasion assay, although with less potency than expected.
组织转谷氨酰胺酶（TG2）是一种多功能蛋白，可在细胞外基质中催化蛋白质交联，并作为细胞内 G 蛋白发挥作用。虽然这两种活性都与人类疾病有关，但它作为 G 蛋白的作用与癌症干细胞的存活和转移表型的维持有关。最近，我们已经表明，靶向共价抑制剂（TCIs）可以选择性地与 TG2 的酶活性位点反应，变构地使其丧失与 GTP 结合的能力。在本工作中，我们专注于这些肽模拟抑制剂的 N 端基团的变化，以提高效率，同时降低 log P 和可旋转键的数量。这种方法导致了 41 种新型抑制剂的合成和评价，其中一些具有极大地提高了对 TG2 的效率和亲和力（例如 TCI 72：K = 1.0 μM，k/K = 4.4×10 M min）。分子建模为这些 TCIs 提供了一个假设的结合模式。对最有效的抑制剂进行了进一步评价，结果表明它们具有极好的同工酶选择性，可阻止 GTP 结合，并具有预期的改善药代动力学性质。它们的生物学活性也在细胞侵袭试验中得到了证实，尽管其效力低于预期。
