Anti-EGFR Antibody-Drug Conjugate Carrying an Inhibitor Targeting CDK Restricts Triple-Negative Breast Cancer Growth

• Published in: Clinical cancer research 2024-08, Vol.30 (15), p.3298-3315
• Main Authors: Cheung, Anthony, Chenoweth, Alicia M, Johansson, Annelie, Laddach, Roman, Guppy, Naomi, Trendell, Jennifer, Esapa, Benjamina, Mavousian, Antranik, Navarro-Llinas, Blanca, Haider, Syed, Romero-Clavijo, Pablo, Hoffmann, Ricarda M, Andriollo, Paolo, Rahman, Khondaker M, Jackson, Paul, Tsoka, Sophia, Irshad, Sheeba, Roxanis, Ioannis, Grigoriadis, Anita, Thurston, David E, Lord, Christopher J, Tutt, Andrew N J, Karagiannis, Sophia N
• Format: Article
• Language: English
• Subjects: Animals; Biological Agents & Therapies; Breast Cancer; Cell Line, Tumor; Cell Proliferation - drug effects; Cetuximab - pharmacology; Cyclin-Dependent Kinases - antagonists & inhibitors; Drug Targets; ErbB Receptors - antagonists & inhibitors; ErbB Receptors - metabolism; Female; Humans; Immunoconjugates - pharmacology; Mice; Protein Kinase Inhibitors - pharmacology; Translational Cancer Mechanisms and Therapy; Triple Negative Breast Neoplasms - drug therapy; Triple Negative Breast Neoplasms - metabolism; Triple Negative Breast Neoplasms - pathology; Xenograft Model Antitumor Assays
• ISSN: 1078-0432; 1557-3265; 1557-3265
• DOI: 10.1158/1078-0432.CCR-23-3110

Anti-EGFR antibodies show limited response in breast cancer, partly due to activation of compensatory pathways. Furthermore, despite the clinical success of cyclin-dependent kinase (CDK) 4/6 inhibitors in hormone receptor-positive tumors, aggressive triple-negative breast cancers (TNBC) are largely resistant due to CDK2/cyclin E expression, whereas free CDK2 inhibitors display normal tissue toxicity, limiting their therapeutic application. A cetuximab-based antibody drug conjugate (ADC) carrying a CDK inhibitor selected based on oncogene dysregulation, alongside patient subgroup stratification, may provide EGFR-targeted delivery. Expressions of G1/S-phase cell cycle regulators were evaluated alongside EGFR in breast cancer. We conjugated cetuximab with CDK inhibitor SNS-032, for specific delivery to EGFR-expressing cells. We assessed ADC internalization and its antitumor functions in vitro and in orthotopically grown basal-like/TNBC xenografts. Transcriptomic (6,173 primary, 27 baseline, and matched post-chemotherapy residual tumors), single-cell RNA sequencing (150,290 cells, 27 treatment-naïve tumors), and spatial transcriptomic (43 tumor sections, 22 TNBCs) analyses confirmed expression of CDK2 and its cyclin partners in basal-like/TNBCs, associated with EGFR. Spatiotemporal live-cell imaging and super-resolution confocal microscopy demonstrated ADC colocalization with late lysosomal clusters. The ADC inhibited cell cycle progression, induced cytotoxicity against high EGFR-expressing tumor cells, and bystander killing of neighboring EGFR-low tumor cells, but minimal effects on immune cells. Despite carrying a small molar fraction (1.65%) of the SNS-032 inhibitor, the ADC restricted EGFR-expressing spheroid and cell line/patient-derived xenograft tumor growth. Exploiting EGFR overexpression, and dysregulated cell cycle in aggressive and treatment-refractory tumors, a cetuximab-CDK inhibitor ADC may provide selective and efficacious delivery of cell cycle-targeted agents to basal-like/TNBCs, including chemotherapy-resistant residual disease.