All Publications


  • Mezigdomide is effective alone and in combination with Menin inhibition in pre-clinical models of KMT2A-r and NPM1c AML. Blood Bourgeois, W., Cutler, J. A., Aubrey, B. J., Wenge, D., Perner, F., Martucci, C., Henrich, J. A., Klega, K., Nowak, R. P., Donovan, K. A., Boileau, M., Wen, Y., Hatton, C., Apazidis, A. A., Olsen, S. N., Kirmani, N., Pikman, Y., Pollard, J. A., Perry, J. A., Sperling, A. S., Ebert, B. L., McGeehan, G. M., Crompton, B. D., Fischer, E. S., Armstrong, S. A. 2023

    Abstract

    Small molecules that target the MENIN-KMT2A protein-protein interaction (Menin inhibitors) have recently entered clinical trials in lysine methyltransferase 2A (KMT2A, MLL1) rearranged (KMT2A-r) and nucleophosmin mutant (NPM1c) acute myeloid leukemia (AML) and are demonstrating encouraging results. However, rationally chosen combination therapy is needed to improve responses and prevent resistance. We have previously identified IKZF1/IKAROS as a target in KMT2A-r AML and shown in preclinical models that IKAROS protein degradation with lenalidomide or iberdomide has modest single-agent activity yet can synergize with Menin inhibitors. Recently, the novel IKAROS degrader mezigdomide was developed with greatly enhanced IKAROS protein degradation. In this study we show that mezigdomide has increased preclinical activity in vitro as a single-agent in KMT2A-r and NPM1c AML cell lines, including sensitivity in cell lines resistant to lenalidomide and iberdomide. Further, we demonstrate that mezigdomide has the greatest capacity to synergize with and induce apoptosis in combination with Menin inhibitors, including in MEN1 mutant models. We show that the superior activity of mezigdomide compared to lenalidomide or iberdomide is due to its increased depth, rate, and duration of IKAROS protein degradation. Single-agent mezigdomide was efficacious in five patient derived xenograft (PDX) models of KMT2A-r and one NPM1c AML. The combination of mezigdomide with the Menin inhibitor VTP-50469 increased survival and prevented and overcame MEN1 mutations that mediate resistance in patients receiving Menin inhibitor monotherapy. These results support prioritization of mezigdomide for early phase clinical trials in KMT2A-r and NPM1c AML, either as a single-agent or in combination with Menin inhibitors.

    View details for DOI 10.1182/blood.2023021105

    View details for PubMedID 38096371

  • Chemo-proteomics exploration of HDAC degradability by small molecule degraders. Cell chemical biology Xiong, Y., Donovan, K. A., Eleuteri, N. A., Kirmani, N., Yue, H., Razov, A., Krupnick, N. M., Nowak, R. P., Fischer, E. S. 2021; 28 (10): 1514-1527.e4

    Abstract

    Targeted protein degradation refers to the use of small molecules that recruit a ubiquitin ligase to a target protein for ubiquitination and subsequent proteasome-dependent degradation. While degraders have been developed for many targets, key questions regarding degrader development and the consequences of acute pharmacological degradation remain, specifically for targets that exist in obligate multi-protein complexes. Here, we synthesize a pan-histone deacetylase (HDAC) degrader library for the chemo-proteomic exploration of acute degradation of a key class of chromatin-modifying enzymes. Using chemo-proteomics, we not only map the degradability of the zinc-dependent HDAC family identifying leads for targeting HDACs 1-8 and 10 but also explore important aspects of degrading epigenetic enzymes. We discover cell line-driven target specificity and that HDAC degradation often results in collateral loss of HDAC-containing repressive complexes. These findings potentially offer a new mechanism toward controlling chromatin structure, and our resource will facilitate accelerated degrader design and development for HDACs.

    View details for DOI 10.1016/j.chembiol.2021.07.002

    View details for PubMedID 34314730

  • Structure-Guided Design of a "Bump-and-Hole" Bromodomain-Based Degradation Tag. Journal of medicinal chemistry Nowak, R. P., Xiong, Y., Kirmani, N., Kalabathula, J., Donovan, K. A., Eleuteri, N. A., Yuan, J. C., Fischer, E. S. 2021; 64 (15): 11637-11650

    Abstract

    Chemical biology tools to modulate protein levels in cells are critical to decipher complex biology. Targeted protein degradation offers the potential for rapid and dose-dependent protein depletion through the use of protein fusion tags toward which protein degraders have been established. Here, we present a newly developed protein degradation tag BRD4BD1L94V along with the corresponding cereblon (CRBN)-based heterobifunctional degrader based on a "bump-and-hole" approach. The resulting compound XY-06-007 shows a half-degradation concentration (DC50, 6 h) of 10 nM against BRD4BD1L94V with no degradation of off-targets, as assessed by whole proteome mass spectrometry, and demonstrates suitable pharmacokinetics for in vivo studies. We demonstrate that BRD4BD1L94V can be combined with the dTAG approach to achieve simultaneous degrader-mediated depletion of their respective protein fusions. This orthogonal system complements currently available protein degradation tags and enables investigation into the consequences resulting from rapid degradation of previously undruggable disease codependencies.

    View details for DOI 10.1021/acs.jmedchem.1c00958

    View details for PubMedID 34279939

  • Genetically Encoded Stealth Nanoparticles of a Zwitterionic Polypeptide-Paclitaxel Conjugate Have a Wider Therapeutic Window than Abraxane in Multiple Tumor Models. Nano letters Banskota, S., Saha, S., Bhattacharya, J., Kirmani, N., Yousefpour, P., Dzuricky, M., Zakharov, N., Li, X., Spasojevic, I., Young, K., Chilkoti, A. 2020; 20 (4): 2396-2409

    Abstract

    Small-molecule therapeutics demonstrate suboptimal pharmacokinetics and bioavailability due to their hydrophobicity and size. One way to overcome these limitations-and improve their efficacy-is to use "stealth" macromolecular carriers that evade uptake by the reticuloendothelial system. Although unstructured polypeptides are of increasing interest as macromolecular drug carriers, current recombinant polypeptides in the clinical pipeline typically lack stealth properties. We address this challenge by developing new unstructured polypeptides, called zwitterionic polypeptides (ZIPPs), that exhibit "stealth" behavior in vivo. We show that conjugating paclitaxel to a ZIPP imparts amphiphilicity to the polypeptide chain that is sufficient to drive its self-assembly into micelles. This in turn increases the half-life of paclitaxel by 17-fold compared to free paclitaxel, and by 1.6-fold compared to the nonstealth control, i.e., ELP-paclitaxel. Treatment of mice bearing highly aggressive prostate or colon cancer with a single dose of ZIPP-paclitaxel nanoparticles leads to near-complete eradication of the tumor, and these nanoparticles have a wider therapeutic window than Abraxane, an FDA-approved taxane nanoformulation.

    View details for DOI 10.1021/acs.nanolett.9b05094

    View details for PubMedID 32125864

  • Engineering the Architecture of Elastin-Like Polypeptides: From Unimers to Hierarchical Self-Assembly. Advanced therapeutics Saha, S., Banskota, S., Roberts, S., Kirmani, N., Chilkoti, A. 2020; 3 (3)

    Abstract

    Well-defined tunable nanostructures formed through the hierarchical self-assembly of peptide building blocks have drawn significant attention due to their potential applications in biomedical science. Artificial protein polymers derived from elastin-like polypeptides (ELPs), which are based on the repeating sequence of tropoelastin (the water-soluble precursor to elastin), provide a promising platform for creating nanostructures due to their biocompatibility, ease of synthesis, and customizable architecture. By designing the sequence and composition of ELPs at the gene level, their physicochemical properties can be controlled to a degree that is unmatched by synthetic polymers. A variety of ELP-based nanostructures are designed, inspired by the self-assembly of elastin and other proteins in biological systems. The choice of building blocks determines not only the physical properties of the nanostructures, but also their self-assembly into architectures ranging from spherical micelles to elongated nanofibers. This review focuses on the molecular determinants of ELP and ELP-hybrid self-assembly and formation of spherical, rod-like, worm-like, fibrillar, and vesicle architectures. A brief discussion of the potential biomedical applications of these supramolecular assemblies is also included.

    View details for DOI 10.1002/adtp.201900164

    View details for PubMedID 34307837

    View details for PubMedCentralID PMC8297442

  • Long circulating genetically encoded intrinsically disordered zwitterionic polypeptides for drug delivery. Biomaterials Banskota, S., Yousefpour, P., Kirmani, N., Li, X., Chilkoti, A. 2019; 192: 475-485

    Abstract

    The clinical utility of many peptide and protein drugs is limited by their short in-vivo half-life. To address this limitation, we report a new class of polypeptide-based materials that have a long plasma circulation time. The design of these polypeptides is motivated by the hypothesis that incorporating a zwitterionic sequence, within an intrinsically disordered polypeptide motif, would impart "stealth" behavior to the polypeptide and increase its plasma residence time, a behavior akin to that of synthetic stealth polymers. We designed these zwitterionic polypeptides (ZIPPs) with a repetitive (VPX1X2G)n motif, where X1 and X2 are cationic and anionic amino acids, respectively, and n is the number of repeats. To test this hypothesis, we synthesized a set of ZIPPs with different pairs of cationic and anionic residues with varied chain length. We show that a combination of lysine and glutamic acid in the ZIPP confer superior pharmacokinetics, for both intravenous and subcutaneous administration, compared to uncharged control polypeptides. Finally, to demonstrate their clinical utility, we fused the best performing ZIPP sequence to glucagon-like peptide-1 (GLP1), a peptide drug used for treatment of type-2 diabetes and show that the ZIPP-GLP1 fusion outperforms an uncharged polypeptide of the same molecular weight in a mouse model of type-2 diabetes.

    View details for DOI 10.1016/j.biomaterials.2018.11.012

    View details for PubMedID 30504081

    View details for PubMedCentralID PMC6376874