O'Hearn, N. | bioRxiv Science

bioRxiv2026

Epigenetic Reactivation of Lineage Differentiation to Target Leukemia

Chromatin regulation critically influences gene expression and cancer progression, yet the functions of chromatin adaptors remain incompletely defined. Using focused CRISPR screening, we identified TRIM28, a multi-domain chromatin adaptor, as a dependency in acute leukemia, where its depletion impaired leukemia cell proliferation in vitro and in vivo, while activating neutrophil differentiation programs. Integrative transcriptomic and chromatin profiling revealed that TRIM28 acts as a co-repressor of neutrophil-associated loci independently of H3K9 methylation, and that TRIM28 loss drives terminal differentiation of leukemia cells into functionally mature neutrophil-like cells with reduced leukemic potential. We developed a selective small-molecule TRIM28 inhibitor that binds the TRIM28 PHD-bromodomain, phenocopies TRIM28 loss across biochemical and cellular assays, exhibits low micromolar anti-leukemia activity, induces neutrophil differentiation, and synergizes with Menin inhibition. Together, these findings, spanning target discovery, mechanism of action, and chemical probe development, establish TRIM28 as a regulator of myeloid cell fate and a promising pro-differentiation therapeutic target in acute leukemia.

cancer biology↗

bioRxiv2026

PRMT5 inhibitors actively promote metastatic progression of lung adenocarcinoma

Epigenetic changes are a major driver of cancer progression, placing considerable focus on epigenetic regulators as therapeutic targets. Protein arginine methyltransferase 5 (PRMT5) is one such regulator, and numerous PRMT5 inhibitors (PRMT5i) in clinical trials. Despite this, the mechanisms and consequences of PRMT5i-resistance are unknown. Here, we demonstrate that aggressive cancer progression is an inbuilt feature of PRMT5i-resistance acquisition in lung adenocarcinoma (LUAD). Independently-generated resistant cell lines gain dedifferentiation signatures that typify late-stage disease and show increased metastatic potential in vivo. We establish that these state shifts are a direct consequence of PRMT5i action; treatment induces rapid and widespread chromatin rewiring, enabling derepression of late-stage disease states that are stably established in resistant cells. Notably, treatment of lung tumor-bearing mice drives rapid disease advancement without decreasing tumor burden, showing that drug-induced disease progression supersedes any benefits from PRMT5 inhibition in vivo. Furthermore, analyses of human cell lines and patient cohorts supports the notion of PRMT5 inhibition-mediated dedifferentiation. Collectively our data show that PRMT5i can actively promote self-resistance and disease progression in different tumor types. This raises serious concerns for the use of PRMT5i in patients, arguing that clinical studies should consider the possibility of drug-induced plasticity, resistance, and disease advancement.

cancer biology↗