Supramolecular hydrogels are emerging as next-generation alternatives to synthetic polymers for drug delivery applications. Self-assembling peptides are a promising class of supramolecular gelators for in vivo drug delivery that have been slow to be adopted despite advantages in biocompatibility due to the relatively high cost of producing synthetic peptide hydrogels compared to synthetic polymer gels. Herein, we describe the development and use of inexpensive low-molecular-weight cationic derivatives of phenylalanine (Phe) as injectable hydrogels for in vivo delivery of an anti-inflammatory drug, diclofenac, for pain mitigation in a mouse model. N-Fluorenylmethoxycarbonyl phenylalanine (Fmoc-Phe) derivatives were modified at the carboxylic acid with diaminopropane (DAP) to provide Fmoc-Phe-DAP molecules that spontaneously and rapidly self-assemble in aqueous solutions upon addition of physiologically relevant sodium chloride concentrations to give hydrogels. When self-assembly occurs in the presence of diclofenac, the drug molecule is efficiently encapsulated within the hydrogel network. These hydrogels exhibit robust shear-thinning behavior, mechanical stability, and drug release profiles to enable application as injectable hydrogels for in vivo drug delivery. Delivery of diclofenac in vivo was demonstrated by a localized injection of an Fmoc-F 5 -Phe-DAP/diclofenac hydrogel into the ankle joint of mice with induced ankle injury and associated inflammation-induced pain. Remediation of pain in the ankle joint was observed immediately after the initial injection and was sustained for a period of nearly 2 weeks, while diclofenac controls remediated pain for less than 1 day. These data demonstrate the promise of these supramolecular hydrogels as inexpensive next-generation materials for sustained and localized drug delivery in vivo.

Targeted protein degradation with molecular glue degraders has arisen as a powerful therapeutic modality for eliminating classically undruggable disease-causing proteins through proteasomemediated degradation. However, we currently lack rational chemical design principles for converting protein-targeting ligands into molecular glue degraders. To overcome this challenge, we sought to identify a transposable chemical handle that would convert protein-targeting ligands into molecular degraders of their corresponding targets. Using the CDK4/6 inhibitor ribociclib as a prototype, we identified a covalent handle that, when appended to the exit vector of ribociclib, induced the proteasome-mediated degradation of CDK4 in cancer cells. Further modification of our initial covalent scaffold led to an improved CDK4 degrader with the development of a but-2-ene-1,4-dione ("fumarate") handle that showed improved interactions with RNF126. Subsequent chemoproteomic profiling revealed interactions of the CDK4 degrader and the optimized fumarate handle with RNF126 as well as additional RING-family E3 ligases. We then transplanted this covalent handle onto a diverse set of protein-targeting ligands to induce the degradation of BRD4, BCR-ABL and c-ABL, PDE5, AR and AR-V7, BTK, LRRK2, HDAC1/3, and SMARCA2/4. Our study undercovers a design strategy for converting protein-targeting ligands into covalent molecular glue degraders.

Supramolecular hydrogels have great potential as biomaterials for sustained delivery of therapeutics.

Targeted protein degradation with molecular glue degraders has arisen as powerful therapeutic modality for eliminating classically undruggable disease-causing proteins through proteasome-mediated degradation. However, we currently lack rational chemical design principles for converting protein-targeting ligands into molecular glue degraders. To overcome this challenge, we sought to identify chemical handles that would convert protein-targeting ligands into molecular glue degraders of their targets. Using the CDK4/6 inhibitor Ribociclib as a testbed, we identified a covalent handle that, when appended to the exit vector of Ribociclib, induced the proteasome-mediated degradation of CDK4 in cancer cells. Covalent chemoproteomic profiling of this CDK4 degrader revealed covalent interactions with cysteine 32 of the RING family E3 ubiquitin ligase RNF126. Optimization of this covalent scaffold led to an improved CDK4 degrader with a methoxyphenyl fumarate handle that showed improved interactions with RNF126. We then identified the minimum covalent chemical handle required for interaction with RNF126. With this knowledge in hand, we transplanted this covalent fumarate handle onto chemically related and un-related protein-targeting ligands to induce the degradation of several proteins across diverse protein classes, including BRD4, BCR-ABL and c-ABL, PDE5, AR and AR-V7, BTK, LRRK2, and SMARCA2. Our study undercovers a potential chemical rational design strategy for converting protein-targeting ligands into covalent molecular glue degraders.