Abstract 4363: Monocyte-specific epigenetic age acceleration and cardiomyopathy risk among survivors of childhood cancer
Authors: Chen Cheng , Dong Qian , Na Qin , Song Nan , Easton John , Mulder Heather L. , Walker Emily , Neale Geoffrey , Finch Emily R. , Li Qian , Yasui Yutaka , Mulrooney Daniel A. , Hudson Melissa M. , Ness Kirsten K. , Zhang Jinghui , Chen Xiang , Wang Hui , Robison Leslie L. , Wang Zhaoming 
Published: April 2023

Abstract
Our assessment of epigenetic age acceleration (EAA), calculated with DNA methylation (DNAm) data generated from bulk DNA derived from peripheral blood mononuclear cells (PBMC), supports accelerated aging in childhood cancer survivors (CCS). It is challenging to disentangle variation of DNAm at cell-type specific levels from the effects of age-dependent cell type composition, and bulk measurements may obfuscate the links between EAA and age-related outcomes (e.g., cardiomyopathy). Methylation profiling was generated using Infinium EPIC BeadChips on PBMC-derived DNA from CCS in the St. Jude Lifetime Cohort. Tensor composition analysis was employed to deconvolute bulk DNAm and infer DNAm at each leukocyte subtype level, i.e., a single n (individuals) by m (DNAm sites) matrix of observed DNAm data was deconvoluted into multiple n by m matrices of DNAm data. Epigenetic age (EA, using Levine’s clock) and EAA (residuals from the fit of a simple linear regression of EA on chronological age at blood draw) were calculated for bulk PBMCs and each cell subtype (CD4T, CD8T, B, natural killer, and monocyte). Cardiomyopathy (CMP) was assessed by echocardiography, and severity graded (2 = moderate, 3 = severe/disabling, 4 = life-threatening and 5 = fatal) using a modified version of the National Cancer Institute Common Terminology Criteria for Adverse Events. Cumulative doses of anthracyclines and mean heart radiation doses (heart-RT) calculated through radiation dosimetry were abstracted from medical records. Associations between EAA and CMP were evaluated by multivariable Cox regression. Cell-type specific EA was highly correlated with bulk EA with Pearson r2 between 0.63 (CD8T) and 0.79 (CD4T), but the linear regression lines of cell-type specific EA against bulk EA differed in both intercept and slope, suggesting heterogeneity across leukocyte subtypes. Cell-type specific EAA was moderately correlated with bulk EAA with Pearson r2 between 0.23 (monocyte) and 0.29 (CD8T). Among 2,044 CCS (median age = 33.7 years), 104 (5.1%) developed CMP (≥grade 3). Among bulk EAA and five cell-type specific EAAs, monocyte EAA was the only one significantly associated with CMP (hazard ratio per standard deviation increase in EAA = 1.25, 95% CI = 1.04-1.50, P = 0.018). Cell sorting of PBMC followed by DNAm is currently underway for further validation. We showed an in-depth view of the variability of EAA across leukocyte subtypes, and more importantly, demonstrated that monocyte EAA was associated with CMP risk. Our novel finding is plausible and consistent with the literature implicating monocyte-derived cardiac macrophages in cardiac remodeling, which can be induced by cardiotoxic cancer treatment exposures in CCS. Therapeutic strategies that prevent deleterious effects of monocytes contributing to adverse cardiac remodeling, while sparing their essential immune functions, may prevent or ameliorate CMP among CCS.
Citation Format: Cheng Chen, Qian Dong, Qin Na, Nan Song, John Easton, Heather L. Mulder, Emily Walker, Geoffrey Neale, Emily R. Finch, Qian Li, Yutaka Yasui, Daniel A. Mulrooney, Melissa M. Hudson, Kirsten K. Ness, Jinghui Zhang, Xiang Chen, Hui Wang, Leslie L. Robison, Zhaoming Wang. Monocyte-specific epigenetic age acceleration and cardiomyopathy risk among survivors of childhood cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4363.