Esterase-activatable dimeric HDAC inhibitor nanotherapeutics for enhanced lymphoma epigenetic therapy.

[BACKGROUND] Despite advances in lymphoma therapy, significant challenges persist including R-CHOP resistance and CAR-T toxicity. Hydroxamate-based histone deacetylase inhibitors (HDACi) like vorinostat (SAHA) offer epigenetic therapeutic potential but are limited by poor bioavailability and rapid clearance.

[METHODS] To overcome these barriers, we rationally designed an esterase- activatable dimeric prodrug by conjugating two SAHA molecules via a glutaric acid linker (SAHA-cc-SAHA). This prodrug co-assembled with DSPE-PEG into nanoparticles (cc-diSAHA NPs). The system was characterized (DLS/TEM), and its drug release profile was assessed with/without porcine liver esterase (PLE). Antitumor activity was evaluated in EL4/A20 lymphoma cells (apoptosis/cycle assays, etc) and EL4 allograft. Transcriptomic mechanisms were deciphered by RNA-seq.

[RESULTS] The cc-diSAHA NPs were uniform spheres (∼74 nm, PDI = 0.187) with excellent colloidal stability and minimal drug leakage (<4 % in 7 days), while enabling rapid drug release upon esterase stimulation (92.4 % within 7 h with PLE). In vitro, they demonstrated broad-spectrum anti-lymphoma activity, inducing G/G arrest and apoptosis, albeit with delayed kinetics versus free formulations, consistent with a sustained-release profile. Transcriptomics revealed multifaceted mechanisms, including potent activation of interferon-mediated immunogenic stress and hematopoietic differentiation, alongside enriched adhesion and redox metabolism pathways. In vivo, intravenous cc-diSAHA NPs suppressed EL4 tumor growth significantly more than oral SAHA (819.36 vs 1594.40 mm³; p < 0.01), without inducing systemic toxicity or organ damage.

[CONCLUSION] This nanoplatform overcomes HDACi delivery barriers by reconciling the stability-activation paradox, providing a therapeutically viable option for lymphoma patients ineligible for standard intensive therapies.