Dataset Information

CX-5461 and Doxorubicin activate a shared DNA damage–associated transcriptional response in human cardiomyocytes

ABSTRACT: CX-5461 (CX) is under investigation for the treatment of late-stage cancers. While CX was first described as an RNA polymerase I inhibitor, it has recently been shown to primarily inhibit the beta isoform of topoisomerase II. This isoform is also inhibited by anthracycline drugs including Doxorubicin (DOX) and mediates the toxic effects of these drugs on the heart. It is unclear whether CX will similarly cause cardiotoxicity. We therefore tested the effects of CX on iPSC-derived cardiomyocytes from six individuals. CX induces cell death in cardiomyocytes at micromolar concentrations. Transcriptome profiling following treatment over time reveals gene expression programs that correspond to the DNA damage response, which are pathways shared with DOX response genes. Micromolar CX concentrations affect heart-specific genes and 14 functionally-validated genes in loci associated with DOX cardiotoxicity. Our data demonstrate the impact of CX on the transcriptome of cardiomyocytes, a potential off-target cell type of the drug.

ORGANISM(S): Homo sapiens

PROVIDER: GSE302122 | GEO | 2025/12/11

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:In recent years, several small molecule cytotoxic drugs have been identified as potential inhibitors of ribosome biogenesis (Drygin et al., 2011; Peltonen et al., 2014a; Peltonen et al., 2014b). CX-5461 is one such drug that has also demonstrated anticancer potential for a wide range of malignancies (Bywater et al., 2012; Cornelison et al., 2017; Devlin et al., 2015; Drygin et al., 2011; Hald et al., 2019; Hein et al., 2017; Ismael et al., 2019; Lawrence et al., 2018; Lee et al., 2017; Negi and Brown, 2015; Taylor et al., 2019; Xu et al., 2017; Yan et al., 2017) (Haddach et al., 2012), and is presently under phase I trials for the treatment of both hematological cancers and solid tumours (Group, 2016; Khot et al., 2019). CX-5461 was initially characterized as an inhibitor of RNA Polymerase I (RPI/PolR1/PolI) that is responsible for the synthesis of the major ribosomal RNAs and the initial step in ribosome biogenesis (Drygin et al., 2011). Since RPI and its corresponding core transcription factors are dedicated to this task alone, they present ideal molecular targets by which to modulate ribosome biogenesis. However, the specificity of CX-5461 has been questioned and it has been suggested that this drug may also act by stabilizing DNA G-quadruplexes or by “poisoning” topoisomerase II (Topo II). Thus, the primary target of this drug and its mode of action are still in doubt. Here we used Deconvolution-ChIP-Seq in NIH3T3 and HEK293T cells treated for different times with CX-5461. The data show that the primary target of CX5461 is the initiation of ribosomal RNA gene (rDNA) transcription. CX-5461 blocks transcription initiation in vitro and in vivo by arresting RNA polymerase I (RPI/Pol1) within the preinitiation complex. In contrast to previous suggestions, CX-5461 does not effect recruitment of the TBP-TAF complex SL1 to the rDNA promoter, the recruitment of the initiation competent RPI-Rrn3 complex or ongoing transcription elongation, arguing against a role for G-quadruplex stabilization or topoisomerase II poisoning. Inhibition of transcription by CX-5461 is not reversible, the RPI-Rrn3 complex remains arrested in the preinitiation complex even after drug removal. This leads to nucleolar stress, extensive DNA damage and cell senescence. Our data show that the cytotoxicity of CX-5461 is the downstream result of the highly specific inhibition of rDNA transcription. The observation that this inhibition is irreversible will be important for the future design of chemotherapeutic strategies and the avoidance of drug resistance.

Project description:TOP2 inhibitors (TOP2i) are effective drugs for breast cancer treatment. However, they can cause cardiotoxicity in some women. The most widely used TOP2i include anthracyclines (AC) Doxorubicin (DOX), Daunorubicin (DNR), Epirubicin (EPI), and the anthraquinone Mitoxantrone (MTX). It is unclear whether women would experience the same adverse effects from all drugs in this class, or if specific drugs would be preferable for certain individuals based on their cardiotoxicity risk profile. To investigate this, we studied the effects of treatment of DOX, DNR, EPI, MTX, and an unrelated monoclonal antibody Trastuzumab (TRZ) on iPSC-derived cardiomyocytes (iPSC-CMs) from six healthy females. All TOP2i induce cell death at concentrations observed in cancer patient serum, while TRZ does not. A sub-lethal dose of all TOP2i induces limited cellular stress but affects calcium handling, a function critical for cardiomyocyte contraction. TOP2i induce thousands of gene expression changes over time, giving rise to four distinct gene expression response signatures, denoted as TOP2i early-acute, early-sustained, and late response genes, and non-response genes. There is no drug- or AC-specific signature. TOP2i early response genes are enriched in chromatin regulators, which mediate AC sensitivity across breast cancer patients. However, there is increased transcriptional variability between individuals following AC treatments. To investigate potential genetic effects on response variability, we first identified a reported set of expression quantitative trait loci (eQTLs) uncovered following DOX treatment in iPSC-CMs. Indeed, DOX response eQTLs are enriched in genes that respond to all TOP2i. Next, we identified 38 genes in loci associated with AC toxicity by GWAS or TWAS. Two thirds of the genes that respond to at least one TOP2i, respond to all ACs with the same direction of effect. Our data demonstrate that TOP2i induce thousands of shared gene expression changes in cardiomyocytes, including genes near SNPs associated with inter-individual variation in response to DOX treatment and AC-induced cardiotoxicity.

Dataset Information

CX-5461 and Doxorubicin activate a shared DNA damage–associated transcriptional response in human cardiomyocytes

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets