Uncovering a novel cell death-independent mechanism of acute anthracycline toxicity in human cardiac fibroblasts

Anthracyclines, such as doxorubicin (Dox), are among the most effective chemotherapeutic agents used to treat various tumors and hematologic malignancies. Despite its potent anticancer effects, the adverse effects of Dox on cardiac function, both acute and chronic, limits its application in the clinic. This cardiotoxicity can be characterized by arrhythmias and left ventricle dysfunction acutely, and cardiac hypertrophy, fibrosis, dilation, decline in cardiac function culminating in heart failure (HF) in the long run. Dox-induced cardiomyopathy (DIC) has been postulated to be caused by several mechanisms, including oxidative stress, mitochondrial dysfunction and DNA damage response. Despite extensive investigations on the cellular and molecular underpinnings of DIC in chronic settings, there continues to be a paucity of information of the acute effects of Dox on the heart, including cell death-independent mechanisms. It is important to note that most cardiotoxicity studies have focused on the cardiomyocytes, with limited efforts to understand the effects on non-myocyte cell population which includes fibroblasts. Our study investigates the effects of acute Dox-exposure in human cardiac fibroblasts (HCFs), which are responsible for extracellular matrix synthesis, mechanical signaling, and differentiation and growth cues in the heart. Healthy adult HCFs treated with a low nanomolar concentration of Dox, or vehicle, for twenty-four hours were processed for unbiased identification of proteins using data independent acquisition (DIA) quantitative proteomic platform. This screen identified the growth differentiation factor 15 (GDF-15) as a potential target of acute Dox exposure in these cells. GDF-15, a member of the TGF-β superfamily, plays a crucial role in cellular stress responses, inflammation, and tissue repair. It has also been implicated in metabolic disease settings. Analysis of human left ventricular tissues from patients with chemotherapy-induced HF, characterized by myocardial structural abnormalities such as increased vacuolization, also showed elevated levels of GDF-15. HCFs from healthy and diabetic (T2D) subjects exposed to Dox exhibited significant upregulation of GDF-15 resulting in compromised mitochondrial respiration and initiation of fibrotic response genes. Suppression of GDF-15 using antisense oligonucleotides reduced these negative effects, thereby restoring cell function. We used state-of-the-art 3D bioprinted cardiac hydrogel constructs generated from induced pluripotent stem cells (healthy and T2D human donors) to demonstrate the effect of the only known GDF15 inhibitor, ponsegromab, which is in clinical trials for treatment of cancer cachexia. Pharmacologic inhibition of GDF15 showed robust decrease in Dox-induced fibroblast remodeling not just in healthy constructs, but also those from T2D subjects. For the first time, this study establishes GDF-15 as a crucial mediator of cell death-independent effects of acute Dox exposure in HCFs, an early DIC biomarker, and a promising therapeutic target for early onset of Dox-induced cardiotoxicity in patients with metabolic diseases. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.