Abstract
Loss-of-function mutations in KMT2D are a striking feature of the germinal centre (GC) lymphomas, resulting in decreased H3K4 methylation and altered gene expression. We hypothesised that inhibition of the KDM5 family, which demethylates H3K4me3/me2, would re-establish H3K4 methylation and restore the expression of genes repressed upon loss of KMT2D. KDM5-inhibition increased H3K4me3 levels and caused an anti-proliferative response in vitro, which was markedly greater in both endogenous and CRISPR-edited KMT2D mutant DLBCL cell lines, whilst tumour growth was inhibited in KMT2D mutant xenografts in vivo. KDM5-inhibition reactivated both KMT2D-dependent and -independent genes, resulting in diminished B-cell receptor signalling and altered expression of BCL2 family members, including BCL2 itself, allowing it to synergise with agents targeting these pathways. KDM5-inhibition may offer an effective therapeutic strategy for ameliorating KMT2D loss-of-function mutations in GC-lymphomas.
Statement of significance We detail a novel way of reverting the effects of loss-of-function mutations in the histone methyltransferase KMT2D by inhibiting the KDM5 demethylase family, increasing levels of H3K4me3 and restoring expression of KMT2D regulated genes.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Financial support: This work was supported by grants from Cancer Research UK (15968 and C355/A26819 awarded to J.F. and 23669 awarded to G.P.) and the Southampton Experimental Cancer Medicine and Cancer Research Centres. A.M. is supported by NIH/NCI R35 CA220499, The Follicular Lymphoma Consortium, LLS TRP 6572-19 and LLS SCOR 7021-20.
Conflicts of interest: The authors declare no potential conflicts of interest. A.M. receives research funding from Janssen and Sanofi, has consulted for Epizyme, Constellation and Jubilant, and is an advisor to KDAC.