The structure-based design, synthesis, and biological activity of a novel indazole-containing inhibitor series for S-adenosyl homocysteine/methylthioadenosine (SAH/MTA) nucleosidase are described. Use of 5-aminoindazole as the core scaffold provided a structure-guided series of low nanomolar inhibitors with broad-spectrum antimicrobial activity. The implementation of structure-based methodologies provided a 6000-fold increase in potency over a short timeline (several months) and an economy of synthesized compounds.

Acute Myeloid Leukemia (AML) is an aggressive hematological malignancy with abnormal progenitor self-renewal and defective white blood cell differentiation. Its pathogenesis comprises subversion of transcriptional regulation, through mutation and by hijacking normal chromatin regulation. Kat2a is a histone acetyltransferase central to promoter activity, that we recently associated with stability of pluripotency networks, and identified as a genetic vulnerability in AML. Through combined chromatin profiling and single-cell transcriptomics of a conditional knockout mouse, we demonstrate that Kat2a contributes to leukemia propagation through preservation of leukemia stem-like cells. Kat2a loss impacts transcription factor binding and reduces transcriptional burst frequency in a subset of gene promoters, generating enhanced variability of transcript levels. Destabilization of target programs shifts leukemia cell fate out of self-renewal into differentiation. We propose that control of transcriptional variability is central to leukemia stem-like cell propagation, and establish a paradigm exploitable in different tumors and distinct stages of cancer evolution.

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