Daniel, M. R. | bioRxiv Science

bioRxiv2025

Integrated Omics Approach to Delineate the Mechanisms of Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX) is an effective chemotherapy whose clinical utility is limited by cardiotoxicity. To investigate underlying mechanisms, we employed a multi-omics approach integrating transcriptomic and proteomic profiling leveraging established mouse models of chronic DOX- induced cardiotoxicity. Five-week-old male mice received weekly DOX (4 mg/kg) or saline injections for six weeks, with heart tissues harvested 4 days post-treatment. Differentially expressed genes (DEGs) and proteins (DEPs) were identified by bulk RNA-seq and proteomics, validated via qPCR and western blot, respectively Key DEPs were validated in plasma samples from DOX-treated breast cancer patients. Additionally, a temporal comparison was conducted between DEPs in the mice hearts 4 days and 6 weeks post-DOX. RNA-seq revealed upregulation of stress-responsive genes (Phlda3, Trp53inp1) and circadian regulators (Nr1d1), with downregulation of Apelin and Cd74. Proteomics identified upregulation of serpina3n, thrombospondin-1, and epoxide hydrolase 1. Plasma SERPINA3 concentrations were significantly elevated in breast cancer patients 24 hours post-DOX. Gene set enrichment analysis (GSEA) revealed upregulated pathways including p53 signaling, apoptosis, and unfolded protein response. Integrated omics analysis revealed 2,089 gene-protein pairs. GSEA of concordant gene-protein pairs implicated p53 signaling, apoptosis, and epithelial-mesenchymal transition in upregulated pathways, while oxidative phosphorylation and metabolic pathways were downregulated. Temporal comparison with a delayed timepoint (6 weeks post-DOX) uncovered dynamic remodeling of cardiac signaling, with early response dominated by inflammatory and apoptotic responses, and delayed response marked by cell cycle and DNA repair pathway activation. This integrated-omics study reveals key molecular pathways and temporal changes in DOX-induced cardiotoxicity, identifying potential biomarkers for future cardioprotective strategies.

pharmacology and toxicology↗

bioRxiv2024

Divergent Immediate and Delayed Effects of Juvenile Exposure to Doxorubicin on the Thymus in C57BL/6 Mice

BackgroundThe understanding of alterations within the immune system following doxorubicin (DOX) chemotherapy, and subsequent restoration, in childhood cancer survivors remains limited. This investigation endeavors to elucidate the immediate and delayed changes in thymic immune cell populations and their phenotypes in response to clinically relevant low doses of DOX in a juvenile mouse model. MethodsMale mice underwent a regimen of repeated low-dose DOX intraperitoneal injections at 4 mg/kg/week for three consecutive weeks. One week after the last dose of DOX, a subset of mice was euthanized to assess the immediate effects of DOX administration. A second subset of mice was euthanized five weeks after the last DOX dose to evaluate the delayed effects. Thymic samples were collected for multiparameter flow cytometry analysis to evaluate alterations in immune cell composition and phenotype. Additionally, quantitative real-time polymerase chain reaction (qRT-PCR) was employed to measure gene expression of- cytokines and senescence markers. ResultsOne week following DOX administration, DOX treatment resulted in significant decline in thymus weight, with notable alterations in immune cell subpopulations. Reduced frequencies of mature CD3+CD4+ and CD3+CD8+ T cells were observed, along with changes in proliferation and exhaustion markers. Gene expression analysis revealed upregulation of Foxn, Pax1, Ifn{gamma}, and Il7 alongside decreased Il6 and Il17 expression. Furthermore, Cdkn1a (p21Cip1) expression was elevated, suggesting immunosenescence. Five weeks following DOX administration, delayed effects of DOX treatment manifested in rebound increase in thymus weight and altered frequencies of CD4+ and CD8+ T cell subsets, with distinct patterns of proliferation and exhaustion observed. Notably, central memory CD4+ T cells exhibited significant decrease in frequency, while naive and effector memory CD4+ T cells showed reduced proliferation (Ki67+) and PD1 expression. Similar trends were observed in CD8+ T cell subsets, indicating selective effects of DOX on T cell differentiation and function. Although expression of thymus-related genes was normalized, p21Cip1 gene expression remained elevated. ConclusionDOX treatment elicits a multifaceted influence on immune cell subsets and thymic weight. Immediate effects included thymic atrophy and reductions in mature T cell populations, while delayed effects showed rebound thymic hyperplasia and selective changes in CD4+ and CD8+ T cell subsets. Notably, both central memory and effector memory T cells exhibited reduced proliferation and exhaustion, suggesting unique impacts of DOX on immune cell function. The enduring elevation in p21Cip1 gene expression 5 weeks after DOX treatment suggests an immunosenescent phenotype. These observations collectively illuminate the formidable task of preserving immune competence and overall well-being in childhood cancer survivors subjected to DOX therapy.

pharmacology and toxicology↗