Optimization and Biological Evaluation of Novel 1<i>H</i>-Pyrrolo[2,3-<i>c</i>]pyridin Derivatives as Potent and Reversible Lysine Specific Demethylase 1 Inhibitors for the Treatment of Acute Myelogenous Leukemia

Lysine-specific demethylase 1 (LSD1) plays a vital role in the epigenetic regulation of various cancers, making it a promising therapeutic target for anticancer treatments. Herein, we designed and synthesized a novel series of 1<i>H</i>-pyrrolo[2,3-<i>c</i>]pyridin derivatives as potent LSD1 inhibitors. A detailed structure-activity relationship exploration was carried out to discover multiple derivatives with nanomolar enzymatic IC₅₀ values. Further biological evaluation demonstrated that these compounds acted as selective and reversible LSD1 inhibitors. The representative compounds exhibited highly potent antiproliferative activity against both AML (MV4-11 and Kasumi-1) and SCLC (NCI-H526) cell lines. Additionally, they effectively activated CD86 mRNA expression in MV4-11 cells and induced differentiation of AML cell lines. Notably, the most promising compound <b>23e</b> showed a favorable oral PK profile and effectively suppressed the tumor growth in an AML xenograft model. Overall, our medicinal chemistry efforts provide compound <b>23e</b> as a lead compound for developing LSD1 inhibitors for the treatment of AML and other advanced malignancies.