Abstract 701: Atherosclerosis Is A Smooth Muscle Cell-driven Tumor-like Disease

Abstract

Background: Atherosclerosis, the leading cause of cardiovascular disease (CVD), is a chronic inflammatory disease involving pathological activation of multiple cell types, such as immunocytes (e.g., macrophage, T cells), smooth muscle cells (SMCs), endothelial cells, etc. Multiple lines of evidence have suggested that SMC “phenotypic switching” plays a central role in atherosclerosis development and complications. Yet, how SMCs and SMC-derived cells (SDCs) modulate atherosclerosis progression and clinical CVD remains poorly understood. Methods: We applied SMC lineage tracing mice and implemented comprehensive molecular and cellular biology, histological, computational, and pharmacological studies to reveal how tumor cell-like activities of SDCs drive the development of atherosclerosis. Results: Oxidative DNA damage occurs during SMC phenotypic switching and increases with the progression of atherosclerosis. Extensive DNA damage-induced genomic instability accumulates in both mouse and human atherosclerosis, especially in SDCs. Indeed, SDCs in atherosclerosis harbor multiple tumor cell-like features, including escape of replicative senescence, clonogenicity, invasive capacity, and ex vivo formation of three-dimensional (3D) spheroids like cancer stem cells. Multiple cancer-associated signaling pathways (e.g., p53, TNFa, NFkB, VEGF) are activated in SDCs. SMC-specific expression of oncogenic Kras G12D accelerates SMC phenotypic switching and exacerbates atherosclerosis. Moreover, we provide proof of concept in mouse models that niraparib, an anti-cancer drug targeting DNA damage repair, attenuates atherosclerosis progression and regresses lesions in advanced disease. Conclusions: Our studies in human and mouse models provide the first systematic evidence that SDCs in atherosclerosis share extensive commonalities with tumor, which deepens our understanding of the disease and opens prospects for novel targeted strategies to prevent and treat atherosclerotic CVD.