KDM2B, an H3K36-specific demethylase, regulates apoptotic response of GBM cells to TRAIL

Area of Science:

• Molecular biology
• Epigenetics
• Cancer research

Background:

• Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in cancer cells.
• TRAIL resistance in cancers is often linked to dysregulation of apoptotic pathway components.
• Epigenetic mechanisms controlling TRAIL response remain largely unelucidated, particularly in glioblastoma multiforme (GBM).

Purpose of the Study:

• To identify novel epigenetic regulators of TRAIL response in glioblastoma multiforme (GBM) cells.
• To investigate the role of KDM2B in regulating apoptosis and TRAIL sensitivity.
• To elucidate the downstream molecular pathways affected by KDM2B in GBM.

Main Methods:

• Utilized a short-hairpin RNA (shRNA) loss-of-function screen targeting 48 genes involved in DNA and histone modification.
• Assessed TRAIL sensitivity, apoptosis markers (caspase activation, PARP cleavage), and cell death kinetics.
• Performed RNA-sequencing to analyze gene expression changes upon KDM2B knockdown.
• Investigated the functional role of Harakiri (HRK) in KDM2B-mediated sensitization.
• Evaluated tumor growth in vivo following KDM2B silencing.

Main Results:

• Identified KDM2B, an H3K36-specific demethylase, as a novel regulator of TRAIL response.
• KDM2B silencing significantly enhanced TRAIL sensitivity, caspase activation, PARP cleavage, and accelerated apoptosis.
• KDM2B loss led to derepression of proapoptotic genes (HRK, caspase-7, DR4) and repression of antiapoptotic genes.
• Upregulation of HRK partially mediated the apoptosis sensitization.
• KDM2B-silenced tumors exhibited reduced growth in vivo.

Conclusions:

• KDM2B epigenetically regulates key apoptosis components in GBM cells.
• KDM2B acts as a negative regulator of TRAIL-induced apoptosis.
• Targeting KDM2B represents a potential therapeutic strategy to overcome TRAIL resistance in glioblastoma.