Histone H3K27M is a driving mutation in diffuse intrinsic pontine glioma (DIPG), a deadly pediatric brain tumor. The malignant and treatment-resistant brain tumor is a target for anti-cancer studies using cell penetrating peptides.

Through a global inhibition of PRC2 catalytic activity and displacement of H3K27me2/3, H3K27M reshapes the epigenome and promotes oncogenesis of DIPG. Consequentially, the histone modification H3K36me2, antagonistic to H3K27me2/3, is elevated. The relationship and role of H3K36me2 in H3K27M-DIPG was investigated by approaches to its upstream catalyzing enzymes, NSD1 and NSD2, the “writers”, and its downstream binding factors, LEDGF and HDGF2, the “readers”.

Tumor-promoting transcriptional programs in H3K27M-DIPG were found to be disrupted by loss of NSD1 and NSD2, thus impeding cellular proliferation and tumorigenesis.
Downstream, a chemically modified peptide mimicking endogenous H3K36me2 was found to dislodge LEDGF and HDGF2 from chromatin. As LEDGF and HDGF2 are the main readers mediating the protumorigenic effects downstream of NSD1/2-H3K36me2, dislodging them resulted in inhibition of H3K27M-DIPG proliferation.

In this study, the chemically modified peptides used were cell penetrating peptides purchased from LifeTein.

Reference: Sci. Adv. 2021 Jul 14; 7(29)