Biology subjects

Watts, J. M.

Publications and source records attributed to Watts, J. M..

3 recordsLinked to original sources

bioRxiv2025

Co-targeting menin and LSD1 dismantles oncogenic programs and restores differentiation in MLL-rearranged AML

Acute myeloid leukemia (AML) harboring MLL (MLL1, KMT2A) rearrangement (MLL-r) remains a lethal subtype with limited durable responses to single-agent menin inhibition. To define rational combination strategies, we performed a high-throughput screen of >900 epigenetic modulators in combination with menin inhibition in MLL-r AML models. This uncovered consistent synergy between menin and lysine-specific demethylase 1 (LSD1) inhibition, including with the clinical agent iadademstat. Mechanistically, LSD1 was found to interact with LEDGF/p75 (PSIP1), a chromatin-anchoring cofactor of the menin-MLL complex at H3K36me3 marked euchromatin. Chromatin profiling revealed extensive co-occupancy of LSD1 and menin-MLL components at leukemogenic loci in MLL-r AML cells. Dual inhibition of menin and LSD1 dismantled this chromatin complex, evicted H3K36me3 from LEDGF-bound sites, and reprogrammed transcription toward myeloid differentiation. Combined menin and LSD1 blockade repressed canonical MLL targets, including HOXA9, MYC, FLT3, PBX3, and CDK6, while restoring H3K36me3 and H3K4me3 and activating differentiation-associated genes. In vivo, the combination produced potent antileukemic effects in both MOLM-13 and MLL-r patient-derived xenografts, markedly reducing leukemic burden and extending survival without overt toxicity. These findings identify LSD1 as a critical cofactor of the menin-MLL-LEDGF axis and establish concurrent menin and LSD1 inhibition as a mechanistically informed combinatorial therapeutic approach in MLL-r AML.

cancer biology↗

bioRxiv2025

Balancing Activation and Repression: CoREST-p300 Antagonism Controls Retinoic Acid-Driven Differentiation in AML

The histone demethylase KDM1A (LSD1), a component of the CoREST corepressor complex, is highly expressed in hematologic malignancies and regulates hematopoietic differentiation. Despite its essential developmental role, LSD1 inhibition has emerged as a promising strategy to enhance retinoic acid (RA)-responsive gene expression in subsets of acute myeloid leukemia (AML). Here, we show that LSD1 physically interacts with RAR/RXR heterodimers at specific genomic loci, restricting chromatin accessibility and transcriptional activation of differentiation programs. Single-agent inhibition of LSD1 or HDACs promotes only partial differentiation. In contrast, Corin, a dual LSD1/CoREST inhibitor, synergizes with all-trans retinoic acid (ATRA) to induce robust myeloid differentiation and apoptosis. Corin treatment alone does not significantly increase H3K4me3 levels; however, in combination with ATRA, it disrupts CoREST-RAR/RXR complexes and facilitates the recruitment of the coactivator p300. Together, they shift chromatin to an active state, enhancing H3K4me3 via increased transcriptional engagement and coactivator recruitment. Our findings identify the functional antagonism between CoREST and p300 as a regulatory axis of RA signaling in AML. Targeting this mechanism with Corin and ATRA re-sensitizes non-APL AML cells to RA-induced differentiation, suggesting a broader therapeutic approach for overcoming resistance in ATRA-refractory leukemias. SignificanceCo-inhibition of LSD1 and HDACs with Corin, combined with ATRA, reprograms chromatin by replacing CoREST with p300, uniquely activating differentiation-associated genes and offering a targeted strategy for treating AML. Graphical abstract created with BioRender (https://biorender.com). O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/682235v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@1216c81org.highwire.dtl.DTLVardef@15ac53aorg.highwire.dtl.DTLVardef@4a96d2org.highwire.dtl.DTLVardef@f3caaf_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2022

A novel mechanistic framework for precise sequence replacement using reverse transcriptase and diverse CRISPR-Cas systems

CRISPR/Cas systems coupled with reverse transcriptase (RT), such as the recently described Prime editing, allow for site-specific replacement of DNA sequences. Despite widespread testing of Prime editing, it is currently only compatible with type II CRISPR/Cas proteins such as Streptococcus pyogenes and Staphylococcus aureus Cas9. Enabling RT compatibility with other CRISPR/Cas domains, such as type V enzymes with orthogonal protospacer adjacent motif specificities and smaller protein size would expand the range of edits that can be made in therapeutic and industrial applications. We achieve this with a novel mode of DNA editing at CRISPR-targeted sites that reverse transcribes the edit into the target strand DNA (e.g., the complement of the PAM-containing strand), rather than the non-target strand DNA, as in Prime editing. We term this technology RNA encoded DNA replacement of alleles with CRISPR (hereafter, REDRAW). We show that REDRAW extends the utility of RT-mediated editing beyond type II to include multiple type V CRISPR domains. REDRAW features a broad (8-10 bases) targeting window, at which all types of substitutions, insertions and deletions are possible. REDRAW combines the advantages of type V CRISPR domains with the extensive range of genetic variation enabled by RT-mediated, templated sequence replacement strategies.

molecular biology↗