KDM6A regulates immune response genes in multiple myeloma

Area of Science:

• Epigenetics
• Cancer Biology
• Immunology

Background:

• The histone H3 at lysine 27 (H3K27) demethylase, lysine demethylase 6A (KDM6A), functions as a tumor suppressor in various cancers, including multiple myeloma (MM).
• Understanding KDM6A's role in MM pathogenesis is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the genome-wide binding of KDM6A in MM cells.
• To elucidate the mechanisms by which KDM6A regulates immune genes and tumor suppressive functions.
• To explore therapeutic strategies for KDM6A-deficient MM.

Main Methods:

• Creation of isogenic MM cell lines with disrupted KDM6A and tagged endogenous KDM6A.
• Genome-wide chromatin immunoprecipitation (ChIP) analysis to identify KDM6A binding sites.
• Analysis of histone modifications (H3K27ac, H3K27me3) and gene expression.
• Assessment of tumor growth and immune cell infiltration in Kdm6a-deficient mouse models.

Main Results:

• KDM6A binds to genes involved in immune recognition and cytokine signaling.
• KDM6A directly binds and activates NLRC5 and CIITA, key regulators of major histocompatibility complex (MHC) genes.
• KDM6A loss leads to decreased H3K27 acetylation at enhancers, increased H3K27 trimethylation in gene bodies, and reduced gene expression.
• Inhibition of HDAC3 restores MHC expression in KDM6A-deficient cells.
• Loss of Kdm6a promotes tumor growth and reduces T-cell infiltration in vivo.

Conclusions:

• KDM6A is a critical regulator of immune gene expression in multiple myeloma.
• Targeting histone acetylation pathways, such as with HDAC3 inhibitors, can restore immunogenicity in KDM6A-deficient tumors.
• KDM6A's tumor suppressive function is linked to its role in maintaining immune surveillance.