jm9b00255_si_005.pdb (305.71 kB)

Identification of Diketopiperazine-Containing 2‑Anilinobenzamides as Potent Sirtuin 2 (SIRT2)-Selective Inhibitors Targeting the “Selectivity Pocket”, Substrate-Binding Site, and NAD+‑Binding Site

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posted on 30.05.2019, 00:00 by Paolo Mellini, Yukihiro Itoh, Elghareeb E. Elboray, Hiroki Tsumoto, Ying Li, Miki Suzuki, Yukari Takahashi, Toshifumi Tojo, Takashi Kurohara, Yuka Miyake, Yuri Miura, Yuki Kitao, Masayuki Kotoku, Tetsuya Iida, Takayoshi Suzuki
The NAD+-dependent deacetylase SIRT2 represents an attractive target for drug development. Here, we designed and synthesized drug-like SIRT2-selective inhibitors based on an analysis of the putative binding modes of recently reported SIRT2-selective inhibitors and evaluated their SIRT2-inhibitory activity. This led us to develop a more drug-like diketopiperazine structure as a “hydrogen bond (H-bond) hunter” to target the substrate-binding site of SIRT2. Thioamide 53, a conjugate of diketopiperazine and 2-anilinobenzamide which is expected to occupy the “selectivity pocket” of SIRT2, exhibited potent SIRT2-selective inhibition. Inhibition of SIRT2 by 53 was mediated by the formation of a 53-ADP-ribose conjugate, suggesting that 53 is a mechanism-based inhibitor targeting the “selectivity pocket”, substrate-binding site, and NAD+-binding site. Furthermore, 53 showed potent antiproliferative activity toward breast cancer cells and promoted neurite outgrowth of Neuro-2a cells. These findings should pave the way for the discovery of novel therapeutic agents for cancer and neurological disorders.