{"id":2410,"date":"2026-07-30T09:00:00","date_gmt":"2026-07-30T13:00:00","guid":{"rendered":"https:\/\/www.insilens.com\/?p=2410"},"modified":"2026-08-04T20:20:31","modified_gmt":"2026-08-05T00:20:31","slug":"dual-target-protac-suppresses-aml-in-mouse-model","status":"publish","type":"post","link":"https:\/\/www.insilens.com\/?p=2410","title":{"rendered":"Dual-Target PROTAC Suppresses AML in Mouse Model"},"content":{"rendered":"

Institution:<\/strong> University of Florida · Event Type:<\/strong> Peer-Reviewed Preclinical Publication · Modality:<\/strong> Cereblon-Recruiting PROTAC (Celastrol-Derived) · Targets:<\/strong> IKKβ and\/or NR4A1 · Disease Area:<\/strong> Acute Myeloid Leukemia · Publication Date:<\/strong> July 30, 2026 (Oncogene)<\/p>\n

\"Dual-Target<\/p>\n

Summary<\/h4>\n

A peer-reviewed Oncogene study describes A9, a celastrol-derived cereblon-recruiting PROTAC that degrades IKKβ and\/or NR4A1, kills AML cell lines and primary samples, and suppresses KMT2A::MLLT3 leukemia in mice without the neutrophilia associated with direct IKKβ inhibition. The July 30 online publication was recovered in the rolling source-gap scan.<\/p>\n

The work offers a degrader strategy for a biologically defined subset of AML, particularly models with monocytic differentiation. It remains an early preclinical mechanism study. Human pharmacokinetics, proteome-wide selectivity, therapeutic index, durability, manufacturability and the context-dependent role of NR4A1 are unresolved.<\/p>\n

What Happened<\/h4>\n

University of Florida-led researchers linked elevated IKKβ and NR4A1 expression with adverse AML outcomes and reported nonredundant oncogenic functions in selected models. The authors synthesized celastrol-based heterobifunctional degraders and selected A9 based on AML cytotoxicity and cereblon-dependent degradation.<\/p>\n

A9 reduced viability in multiple AML cell lines and primary AML samples. Genetic and pharmacologic experiments supported dependency on IKKβ and\/or NR4A1, while ubiquitin-proteasome and cereblon experiments supported an intended PROTAC mechanism. In a KMT2A::MLLT3 mouse model, A9 attenuated leukemia progression and did not induce neutrophilia.<\/p>\n

The authors disclosed a prior patent family related to celastrol-based degraders. The paper did not provide human dosing, clinical-grade formulation, broad off-target proteomics, definitive normal-HSC safety or comparative efficacy against current AML regimens.<\/p>\n

Biological Rationale<\/h4>\n

IKKβ activates NF-κB signaling, which supports survival and inflammatory programs in a subset of AML. Direct IKKβ inhibition has been limited by toxicity, including neutrophilia. Targeted degradation can eliminate kinase and scaffold functions at substoichiometric exposure and may create a different pharmacologic window.<\/p>\n

NR4A1 Complexity and Molecule Quality<\/h4>\n

The study reports oncogenic NR4A1 activity in certain pro-monocytic AML models, yet prior genetic work described NR4A1 and NR4A3 as tumor suppressors whose loss can promote AML. That apparent contradiction is not a minor caveat: it implies that lineage, expression state, mutation context and target occupancy may determine whether degradation is beneficial or harmful. A biomarker strategy is therefore essential.<\/p>\n

Celastrol is pharmacologically promiscuous and chemically reactive, raising risks for off-target effects, poor solubility and narrow systemic tolerability. Converting celastrol into a PROTAC may improve event-driven target engagement but also increases molecular weight and complexity. Full degradation proteomics, ternary-complex characterization, oral or parenteral exposure, tissue distribution and metabolite safety are needed before treatment readiness can be judged.<\/p>\n

Disease Translation<\/h4>\n

AML contains genomically and phenotypically diverse stem and progenitor compartments. Activity in KMT2A::MLLT3 and monocytic models provides a starting hypothesis, not broad target validation. Effects on normal hematopoietic stem cells, mature myeloid function, marrow niche and immune competence will determine therapeutic index. Combining A9 with venetoclax, hypomethylating agents or menin inhibitors could be rational but may amplify cytopenias or select resistant clones.<\/p>\n

Reading the Signal<\/h4>\n

One plausible reading is that dual degradation bypasses the toxicity and incomplete pathway suppression of conventional IKKβ inhibitors. Supporting evidence includes cereblon dependence, primary-sample activity and absence of neutrophilia in the mouse model. Contradicting evidence is the absence of comparative exposure-matched inhibitor studies and limited safety characterization.<\/p>\n

A second plausible reading is that A9’s apparent efficacy reflects broader celastrol-driven polypharmacology rather than a portable dual-target degrader mechanism. Supporting evidence includes celastrol’s known promiscuity and the compound’s ability to affect either target. Against it, rescue and pathway experiments support target-linked degradation, and proteasome dependence is consistent with PROTAC activity.<\/p>\n

The thesis would be upgraded by proteome-wide selectivity, target-specific rescue, pharmacokinetic-pharmacodynamic coupling, efficacy in multiple patient-derived xenografts and a favorable normal-HSC margin. It would be downgraded by reactive-metabolite toxicity, loss of activity in immunocompetent or diverse AML models, or harm in NR4A1-tumor-suppressor contexts. Failure to separate antileukemic exposure from normal-marrow toxicity would falsify the translational thesis.<\/p>\n

Signal Extraction<\/h4>\n
    \n
  • Modality:<\/strong> Celastrol-derived, cereblon-recruiting PROTAC.<\/li>\n
  • Targets:<\/strong> IKKβ and\/or NR4A1 in selected AML contexts.<\/li>\n
  • Evidence:<\/strong> Cell lines, primary AML samples and one KMT2A::MLLT3 mouse model.<\/li>\n
  • Positive feature:<\/strong> Antileukemic activity without observed neutrophilia in the reported mouse study.<\/li>\n
  • Critical risks:<\/strong> Target-context dependence, celastrol polypharmacology, normal-HSC safety and exposure.<\/li>\n<\/ul>\n

    InSilens Take<\/h4>\n

    This is a 3\/5 positive\/uncertain technology signal. The study is scientifically interesting because it converts an historically difficult and toxicity-limited AML pathway into a degradation strategy and exposes a lineage-specific NR4A1 hypothesis. It is not treatment-ready. The current evidence supports medicinal-chemistry and biomarker follow-up, not clinical efficacy or safety claims.<\/p>\n

    Company and Product Background<\/h4>\n

    The work was led by investigators at the University of Florida College of Medicine, College of Pharmacy and UF Health Cancer Institute with collaborators at multiple institutions. The researchers have prior intellectual property around celastrol-derived degraders, creating a possible licensing or spinout path if compound optimization succeeds.<\/p>\n

    AML is an aggressive myeloid malignancy driven by genetically and epigenetically abnormal progenitors. IKKβ is a core activator of NF-κB signaling. NR4A1 is an orphan nuclear receptor with context-dependent roles in myeloid differentiation, inflammation and leukemia. PROTACs are heterobifunctional molecules that bring a target protein to an E3 ligase for ubiquitination and proteasomal degradation.<\/p>\n

    Signal Assessment<\/h4>\n

    Signal Importance: 3\/5. Signal Direction: positive\/uncertain. Confidence in Facts: high — the study is peer reviewed and methods are described. Confidence in Interpretation: medium-low — mechanism portability and therapeutic index are unproven.<\/p>\n

    Missing facts include the full degradome, normal-HSC margin, PK\/PD, formulation, toxicology, diverse in vivo validation and IP freedom to operate.<\/p>\n","protected":false},"excerpt":{"rendered":"

    A peer-reviewed Oncogene study describes A9, a celastrol-derived cereblon-recruiting PROTAC that degrades IKK\u03b2 and\/or NR4A1, kills AML cell lines and primary samples, and suppresses KMT2A::MLLT3 leukemia in mice without the neutrophilia associated with direct…<\/p>\n","protected":false},"author":1,"featured_media":2413,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[76,281,280],"class_list":["post-2410","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-technology-modalities","tag-acute-myeloid-leukemia","tag-protac","tag-university-of-florida"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2410","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2410"}],"version-history":[{"count":1,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2410\/revisions"}],"predecessor-version":[{"id":2431,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2410\/revisions\/2431"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/media\/2413"}],"wp:attachment":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2410"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2410"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2410"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}