Table 2 Approaches to identify DOT1L inhibitors with novel scaffolds

Virtual screening (VS)

Low cost and convenience

DC_L115 was identified by combining structure-based VS with biochemical analysis [24]

As a target-specific scoring function, the SAM score was developed and combined with VS to successfully identify a novel class of DOT1L inhibitors with a scaffold of [1,2,4]-triazolo-[3,4-b][1,3,4]-thiadiazole [25]

Two novel DOT1L inhibitors were identified by means of ligand-based and structure-based approaches [26]

DOT1L inhibitors with a unique non-nucleoside scaffold were identified by structure-based VS adapted from a nucleoside-focused library [16]

Fragment-based drug discovery (FBDD)

The small, low complexity chemical fragments of 6–15 heavy atoms are screened to bind to or inhibit the activity of a target, moreover, the fragments are structurally understood

A weak fragment-based screening hit identified by SPR was cocrystallized with DOT1L and optimized using structure-based ligand optimization, resulting in a series of non-nucleoside inhibitors [27]

In the context of a comprehensive DOT1L hit finding strategy, a non-nucleoside fragment mimicking key interactions of SAM bound to DOT1L was identified and followed by ligand optimization, resulting in a novel inhibitor [28]

High-throughput screening (HTS)

HTS platform routinely screens thousands of drug pairs in vitro setting

A luminescence-based coupled assay was used to measure DOT1L-catalyzed nucleosome methylation and miniaturized to perform HTS screening of the Novartis compound collection in 1536-well plates. Finally, a novel DOT1L inhibitor was identified [29]

A HTS platform based on the AlphaLISA method was developed and screened a compounds library containing approximately 20,000 chemicals, and two promising candidate compounds were identified [30]

A structure-guided optimization of a HTS hit led to the discovery of new potent DOT1L inhibitors for in vivo evaluations [31]