Doxorubicin induces large-scale and differential H2A and H2B redistribution in live cells

Abstract

We observed prominent effects of doxorubicin (Dox), an anthracycline widely used in anticancer therapy, on the aggregation and intracellular distribution of both partners of the H2A-H2B dimer, with marked differences between the two histones. Histone aggregation, assessed by Laser Scanning Cytometry via the retention of the aggregates in isolated nuclei, was observed in the case of H2A. The dominant effect of the anthracycline on H2B was its massive accumulation in the cytoplasm of the Jurkat leukemia cells concomitant with its disappearance from the nuclei, detected by confocal microscopy and mass spectrometry. A similar effect of the anthracycline was observed in primary human lymphoid cells, and also in monocyte-derived dendritic cells that harbor an unusually high amount of H2B in their cytoplasm even in the absence of Dox treatment. The nucleo-cytoplasmic translocation of H2B was not affected by inhibitors of major biochemical pathways or the nuclear export inhibitor leptomycin B, but it was completely diminished by PYR-41, an inhibitor with pleiotropic effects on protein degradation pathways. Dox and PYR-41 acted synergistically according to isobologram analyses of cytotoxicity. These large-scale effects were detected already at Dox concentrations that may be reached in the typical clinical settings, therefore they can contribute both to the anti-cancer mechanism and to the side-effects of this anthracycline.

The missing linker: emerging trends for H1 variant-specific functions

“…A major function of H1.2 as reported by many groups is its function in DDR (Fig. 5A-D; Konishi et al 2003;Giné et al 2008;Kim et al 2008Kim et al , 2012Okamura et al 2008;Rulten et al 2011;Thorslund et al 2015;Mandemaker et al 2017;Li et al 2018;Nánási et al 2020). However, this H1.2 function is not quite straightforward.…”

“…the cytoplasm in response to DNA damage (Fig. 5A; Konishi et al 2003;Giné et al 2008;Okamura et al 2008;Nánási et al 2020). These studies demonstrate that in response to DNA damaging agents such as X-ray, etoposide, bleomycin, and doxorubicin, H1.2 is translocated from the nucleus to the cytoplasm in a p53-dependent manner.…”

“…First, H1.2 has been shown to be associated with both the induction of apoptosis (Fig. 5A; Konishi et al 2003;Giné et al 2008;Okamura et al 2008;Nánási et al 2020) and in the promotion of a prosurvival DDR (Fig. 5B-D; Kim et al 2012;Thorslund et al 2015;Mandemaker et al 2017).…”

Doxorubicin-induced p53 interferes with mitophagy in cardiac fibroblasts

“…There are a number of factors that could play into the reduced proliferation of the p53 -/cells. DOX can alter gene expression through multiple mechanisms, such as histone eviction and redistribution [51,52]. One study demonstrated "metabolic re-wiring" with suppression of pathways necessary for the G1 phase of the cell cycle [53].…”

Chromatin‐modifying drugs and metabolites in cell fate control

“…It is possible that Dox's amino sugar competes with histone H4‐Arg residues for binding of the DNA minor groove 139 . Another study showed that Dox can evict H2A from chromatin and evict H2B from the nucleus to the cytoplasm 140 . Interestingly, Dox only binds to transcriptionally active regions 52,139,141 and enhances nucleosome renewal in these regions, independently of the DNA damage response 52 .…”