Abstract 6735: DNA-templated, spatially controlled proteolysis targeting chimeras enable coordinated degradation of the Cyclin D1-CDK4/6 complex.

Abstract Background: Hyperactivation of the Cyclin D-CDK4/6 complex drives tumor proliferation across cancers. Although CDK4/6 inhibitors provide clinical benefit, durability is limited by resistance and by Cyclin D1’s CDK-independent oncogenic functions that are not addressed by kinase blockade. A strategy that removes the entire Cyclin D1-CDK4/6 complex could suppress both kinase-dependent and independent signaling; however, Cyclin D1 lacks a druggable active site, and prior PROTACs have degraded CDK4/6 individually rather than the intact complex. These gaps motivated the development of DNA templated degraders to program geometry and enable synchronous complex degradation. Methods: This study engineered DNA-templated proteolysis-targeting chimeras (DTACs) by positioning a CDK4/6 binder and an E3 ligase recruiter on complementary oligonucleotides, enabling systematic variation of intermolecular distance and orientation. A panel of DTACs was profiled for target engagement and degradation (Cyclin D1, CDK4, CDK6), cell-cycle distribution, and antiproliferative activity across cancer cell models. Lead constructs were evaluated for in vivo target degradation and antitumor activity in xenograft models. Results: Spatial programming dictated degrader performance: DTAC variants exhibited distance- and orientation-dependent degradation of the Cyclin D1-CDK4/6 complex. The optimized construct induced synchronous loss of Cyclin D1 together with CDK4 and CDK6, yielding pronounced G1 arrest and suppression of cellular proliferation. In a xenograft mouse model, lead product exhibited potent therapeutic efficacy by effectively degrading Cyclin D1−CDK4/6 and suppressing tumor growth. Conclusions: DNA templating provides a modular strategy to control degrader geometry and achieve synchronized degradation of multi-protein complexes. DTACs enable coordinated Cyclin D1-CDK4/6 degradation with functional pathway blockade and antitumor activity. Overall, these findings demonstrate the feasibility of DTAC as a rapid, scalable, and modular platform for the spatial control of functional inhibitors for optimal effectiveness, making it a promising method for proximity-based therapeutics. Citation Format: Rong Zheng, Abhay Prasad, Deeksha Satyabola, Yang Xu, Subhajit Roy, Yichen Yan, Petr Sulc, Hao Yan. DNA-templated, spatially controlled proteolysis targeting chimeras enable coordinated degradation of the Cyclin D1-CDK4/6 complex abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6735.