ROR1 Is Expressed in Diffuse Large B-Cell Lymphoma (DLBCL) and a Small Molecule Inhibitor of ROR1 (KAN0441571C)...

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• Receptor tyrosine kinase ROR1 is overexpressed in several malignancies, including diffuse large B-cell lymphoma (DLBCL).
• ROR1 expression is significantly higher in primary refractory DLBCL, Richter's syndrome, and transformed follicular lymphoma compared to other DLBCL subtypes.
• Preliminary survival data suggest ROR1 expression may impact outcomes in relapsed/refractory DLBCL patients.

Purpose of the Study:

• To investigate the clinical and functional inhibitory aspects of ROR1 in DLBCL.
• To evaluate the efficacy of a novel small molecule ROR1 inhibitor, KAN0441571C, in DLBCL models.
• To explore the combination therapy of ROR1 inhibition with existing DLBCL treatments.

Main Methods:

• ROR1 expression analysis in DLBCL patient samples.
• In vitro studies using ROR1+ DLBCL cell lines treated with KAN0441571C, venetoclax, and ibrutinib.
• Assessment of apoptosis, protein expression (BCL-2, MCL-1), and pathway activation (Wnt pathway).
• In vivo efficacy study in a zebrafish DLBCL xenograft model.

Main Results:

• KAN0441571C induced apoptosis in ROR1+ DLBCL cell lines, comparable to venetoclax and superior to ibrutinib.
• Combination therapy with KAN0441571C and venetoclax resulted in near-complete cell killing.
• Apoptosis was associated with downregulation of BCL-2 and MCL-1 and inactivation of PI3Kδ/AKT/mTOR and Wnt/β-catenin pathways.
• KAN0441571C significantly reduced tumor burden in a zebrafish DLBCL model.

Conclusions:

• ROR1 is a promising therapeutic target in DLBCL, particularly in refractory cases.
• Small molecule ROR1 inhibitors like KAN0441571C demonstrate significant anti-lymphoma activity.
• Combination therapy with ROR1 inhibitors and BCL-2 inhibitors offers a potent therapeutic strategy for DLBCL.
• ROR1 inhibitors represent a novel and promising therapeutic approach for DLBCL treatment.