Identifying KDM5B as the synthetic lethal target of KMT2D-mutated osteosarcoma

Area of Science:

• Oncology
• Epigenetics
• Molecular Biology

Background:

• Osteosarcoma (OS) is a common bone cancer in adolescents with a complex epigenetic profile.
• Loss-of-function mutations in Histone methyltransferase KMT2D are observed in various cancers, including OS.
• KMT2D deficiency is linked to the promotion of malignant phenotypes in osteosarcoma.

Purpose of the Study:

• To investigate the role of KMT2D loss in osteosarcoma progression.
• To identify potential therapeutic targets for KMT2D-mutated osteosarcoma.
• To evaluate the efficacy of KDM5B inhibition as a synthetic lethal strategy.

Main Methods:

• Screening of an epigenetic inhibitor library to identify compounds targeting KMT2D-deficient cells.
• KDM5B knockdown using shRNA in KMT2D-knockout (KO) and wild-type osteosarcoma cells.
• Assessment of cell proliferation, migration, and apoptosis.
• Testing KDM5B inhibition efficacy and safety in patient-derived xenograft (PDX) mouse models.

Main Results:

• KDM5B inhibitors selectively killed KMT2D-deficient osteosarcoma cells.
• KDM5B knockdown reduced proliferation and migration while inducing apoptosis in KMT2D-KO cells.
• KDM5B inhibition demonstrated efficiency and safety in preclinical PDX models of KMT2D-low osteosarcoma.

Conclusions:

• KDM5B acts as a synthetic lethal factor in KMT2D-loss osteosarcoma.
• Targeting KDM5B represents a novel therapeutic approach for KMT2D-mutated osteosarcoma.
• This strategy offers a potential treatment avenue for a specific subset of osteosarcoma patients.