Overcoming ADC resistance in advanced colorectal cancer by dual targeting of TROP2 and PERK to suppress Wnt/ß-catenin signaling

Targeted therapy for advanced colorectal cancer (CRC) remains a significant clinical challenge. In this study, we systematically examined the anti-tumor efficacy and underlying mechanisms of IMMU132, an FDA-approved anti-TROP2 antibody conjugate linked to the topoisomerase I inhibitor SN-38, both as a standalone treatment and in combination with the PERK inhibitor GSK2606414 in TROP2-positive advanced CRC. We first established that TROP2 expression was markedly elevated in CRC cohorts and correlated with poor patient prognosis. In vitro experiments demonstrated that IMMU132 inhibited CRC cell proliferation and viability in a dose-dependent manner. In patient-derived xenograft (PDX) models, IMMU132 monotherapy significantly inhibited tumor growth. Mechanistically, transcriptomic analysis indicated that PERK, a key factor in endoplasmic reticulum stress (ERS), may serve as a critical synergistic target for IMMU132's anti-tumour activity. Subsequent screening of various ERS inhibitors revealed that the specific PERK inhibitor GSK2606414 significantly enhanced the effects of IMMU132. In diverse experimental models, including cell lines, organoids, and PDX models, combination therapy exhibited superior anti-tumor effects compared to monotherapy, highlighting a pronounced synergistic effect. Furthermore, transcriptomic analysis showed that combination therapy notably inhibited the Wnt/ß-catenin signaling pathway. Gene set enrichment analysis confirmed significant upregulation of Wnt pathway-related genes, while Western blot analysis showed downregulation of key molecules in the Wnt pathway, including ß-catenin, GSK3B, JUN, and WNT2B, following combination therapy. These findings suggest that the synergistic anti-tumour effects of IMMU132 and GSK2606414 may arise from their dual modulation of ERS and Wnt signalling pathways, offering novel insights for targeted therapy in advanced CRC and informing strategies for combining antibody-drug conjugates (ADCs). Overall design: This study systematically characterized TROP2 expression in colorectal cancer through integrated bioinformatics and tissue microarray analysis, with validation across multiple preclinical models. The TROP2-targeting antibody-drug conjugate IMMU132 demonstrated potent monotherapeutic efficacy across diverse molecular subtypes in cell lines, patient-derived organoids and xenografts. Transcriptomic analysis identified PERK, a key endoplasmic reticulum stress regulator, as crucial to IMMU132's mechanism. The specific PERK inhibitor GSK2606414 significantly enhanced IMMU132's anti-tumor effects through synergistic modulation of both endoplasmic reticulum stress and Wnt/ß-catenin signaling pathways. These findings elucidate IMMU132's mechanism of action and propose a novel combination strategy with strong translational potential for advanced colorectal cancer therapy.