The dual-target molecular glue degrader INNO-235 effectively mediates the degradation of GSPT1 and CK1α, and exhibits potent anti-tumor activity in TP53 mutant burkitt lymphoma Free

Burkitt lymphoma (BL) is characterized by the translocation and dysregulation of the proto-oncogene MYC. Owing to its high aggressiveness, the clinical therapeutics for BL remain unmet. In view of this pathological feature, molecular glue degraders have been widely explored as a targeted therapeutic strategy. This study reports a first-in-class, orally bioavailable dual-target molecular glue degrader that co-degrades GSPT1 and CK1α and demonstrates potent anti-tumor activity in BL.

MYC hyperactivity imposes a non-oncogene addiction to GSPT1, its depletion of which collapses protein synthesis and selectively eradicates MYC-addicted tumor cells. Furthermore, down-regulation of CK1α attenuates MYC expression, implying that co-targeting GSPT1 and CK1α may yield superior therapeutic efficacy. To identify the desired molecular glue, we designed a targeted library focused on cereblon (CRBN) and successfully identified the molecular glue degrader, INNO-235. We found that CRBN functions as the requisite E3 ubiquitin ligase for INNO-235, enabling nanomolar-level, proteasome-dependent degradation of both CK1α and GSPT1. Notably, no impact on IKZF1 or IKZF3 was observed. Additionally, INNO-235 demonstrated minimal toxicity in healthy volunteer-derived peripheral blood mononuclear cells, indicating a potentially favorable therapeutic window. In a systematic evaluation, INNO-235 exhibited potent anti-proliferative activity in BL cell lines, including those with TP53 mutations, as shown by nanomolar IC₅₀ values. At the cellular phenotypic level, INNO-235 treatment significantly induced apoptosis and caused cell cycle arrest at the G0/G1 phase.

In a Daudi cell-derived xenograft mouse model, orally administered INNO-235 exhibited dose-dependent tumor growth inhibition without observable significant changes in mouse body weight. Notably, compared to INNO-220 (a CK1α single-target molecular glue degrader) and MRT-2359 (a GSPT1 single-target molecular glue degrader), INNO-235 demonstrated superior anti-tumor activity and overall survival.

To elucidate INNO-235's mechanism of action, we performed RNA-seq analysis in INNO-235 treated Daudi cells. The results revealed significant enrichment of differentially expressed genes involved in endoplasmic reticulum protein processing, implicating the activation of the integrated stress response (ISR). Subsequent validation confirmed dose-dependent upregulation of key ISR effector (p-eIF2α, ATF4, CHOP) and pro-apoptotic PUMA, concurrent with downregulation of anti-apoptotic BCL-2. These findings indicated that INNO-235 induced p53-independent apoptosis in TP53-mutated BL cells through ISR pathway activation.

In conclusion, INNO-235 represents a first-in-class GSPT1/CK1α dual-target molecular glue degrader with significant therapeutic potential for lymphomas. By inducing both p53-dependent and TP53-independent apoptosis, INNO-235 offers a promising therapeutic strategy for TP53-mutated BL and other MYC-driven malignancies with limited treatment options.