Abstract 16391: Pro-Neoplastic Properties of Small Extracellular Vesicles From Failing Hearts

Abstract

Background: Heart diseases are associated with an increased incidence of cancer independently of shared risk factors. The mechanism beyond this link is complex, unclear and limits our ability to develop effective therapies. We aimed to test the hypothesis that small cardiac extracellular vesicles (sEVs) contribute to the link between HF and cancer. Methods & Results: We used mouse models of heterotopic and orthotopic lung cancer and post-myocardial infarction (MI) heart failure (HF). sEVs were isolated by size exclusion chromatography. To determine the role of cardiac EVs in tumor growth, we focused on sEVs from cardiac mesenchymal stromal cells (cMSCs). cMSCs after MI secreted twice more sEVs, characterized with a unique proteome, compared with cMSCs from sham-MI ( Fig 1A ). cMSC-sEVs from post-MI HF harbored more tumor-promoting cytokines and microRNA (miR), such as periostin, osteopontin, IL-6, TNFα, galectin-3, and miR's 221 and 21. The pro-neoplastic effects of cMSC-sEVs on cancer cells were depended on cancer type, with a marked increase in proliferation and migration of lung and colon cancer cells but only a modest increase with more malignant triple-negative breast and melanoma cancer cells. Next, we inoculated lung cancer cells into mice and found that post-MI HF accelerated tumor growth. Furthermore, adoptive transfer of cMSC-sEVs from failing hearts accelerated tumor growth with and without systemic EV depletion ( Fig 1B ). Finally, we found that spironolactone mitigated the neoplastic effects of HF, attenuated tumor growth ( Fig 1C ), and reduced the number of cMSC-sEVs by 26%. Conclusions: We show, for the first time, that cardiac extracellular vesicles from post-MI failing heart harbor pro-neoplastic properties and promote tumor growth independently of other secreted factors. Spironolactone reduces the number of cardiac extracellular vesicles and the pro-neoplastic effects of post-MI heart failure.