Biology subjects

Ketchum, F.

Publications and source records attributed to Ketchum, F..

4 recordsLinked to original sources

bioRxiv2026

Doxorubicin-induced Cardiotoxicity is Propagated by Paracrine Signaling through Small Extracellular Vesicles

Cardiovascular disease (CVD) is the leading cause of death in the United States and worldwide. While most of these deaths are the result of chronic heart diseases, some CVDs are induced artificially. Doxorubicin (DOX) is a chemotherapeutic that is commonly used to treat breast cancer which is one of the most common types of cancer in the United States. While DOX is an effective anti-cancer agent, over 10% of treated women show signs of acute cardiotoxicity immediately following treatment, and approximately 2% develop severe cardiotoxicity up to 10 years after the end of treatment. Despite this prevalence, the mechanism by which the onset of this cardiotoxicity occurs over time is not well understood. Here, we show that treatment of cardiac cells with DOX changes the cardiac function and the resulting paracrine signaling profile. Subsequent exposure of healthy cells to these altered paracrine agents can recapitulate the effects of direct DOX exposure in 2D and 3D in vitro models. We suggest that this is the result of an altered paracrine miRNA profile and other paracrine factors that propagate the initial disruption caused by direct DOX exposure. Plasma EV miRNA profiling of blinded patient samples revealed distinct clustering by DOX-cardiotoxicity risk, with high-risk patients exhibiting miRNA signatures similar to those from DOX-treated tissue-engineered models. Pathway analysis of the most distinguishing miRNAs linked them to cardiac homeostasis and cardiotoxicity-related mechanisms, supporting the potential of plasma EV miRNAs as noninvasive biomarkers for early risk stratification and personalized cardioprotective interventions in oncological care, and the targeting of key clusters of miRNAs to enhance both understanding of and intervention strategies for preventing the onset of DOX cardiotoxicity.

bioengineering↗

bioRxiv2025

Mitochondria Clearance Enables Macrophage-Driven Maturation of iPSC-Derived Cardiomyocyte Metabolism

Generation of functional engineered myocardial tissue remains a challenge, owing in part to lacking maturity of stem cell-derived cardiomyocytes. Current strategies to mature these cells fall short of achieving in vivo-like physiology. Macrophages, members of the innate immune system, reside in the heart and exert positive effects on cardiomyocyte function. We hypothesized that developmentally informed addition of macrophages to cardiomyocytes would improve their maturity. While some recent studies have added macrophages to stem cell-derived models of the human myocardium, these previous approaches do not replicate the early colonization of the heart. Addition of macrophages to developing cardiomyocytes 8 days after the start of differentiation significantly alters cardiomyocyte behavior. We show that macrophages drive improvements in metabolic capabilities of cardiomyocytes. Developing cardiomyocytes shed lowly polarized mitochondria, adopt a new mitochondria network architecture, and develop more active mitophagy programs after >20 days coculture with macrophages. This interaction is dependent on macrophage MerTK reception of cardiomyocyte-derived mitochondria material. These results inform our understanding of the responsibility of macrophages in the development of the myocardium, and we hope that these interactions can be leveraged to produce more physiologically relevant models of the human myocardium.

bioengineering↗

bioRxiv2025

Instant fluorescence lifetime imaging microscopy reveals mechano-metabolic reprogramming of stromal cells in breast cancer peritumoral microenvironments

The breast peritumor microenvironment (pTME) is increasingly recognized as a mediator of breast cancer progression and treatment resistance. However, if and how growth-induced tumor compressive forces (i.e., solid stresses) influence the breast pTME remains unclear. Here we show using instant fluorescence lifetime imaging microscopy (FLIM)--a frequency-domain FLIM system capable of simultaneous image acquisition and instantaneous data processing--that breast tumor-mimicking in vitro compression promotes metabolic changes in stromal cells found in the breast pTME. Namely, compression shifts NIH3T3 fibroblasts and differentiated 3T3-L1 (d3T3-L1) adipocytes toward a more glycolytic state, while it promotes increased oxidative phosphorylation in 3T3-L1 undifferentiated adipocytes. The gold-standard Seahorse extracellular flux assay fails to capture these changes, underscoring the superior sensitivity of instant FLIM in detecting metabolic shifts. We validate these phenotypic findings at the transcriptomic level via RNA sequencing, confirming that compressed fibroblasts downregulate oxidative phosphorylation and upregulate glycolysis compared to uncompressed controls. We further demonstrate that compression induces mitochondrial dysregulation in undifferentiated adipocytes, driven in part by upregulated mitophagy and disrupted fusion dynamics. Finally, we confirm that these stromal cell types recapitulate these distinct metabolic states in human breast cancer patient samples, consistent with our in vitro findings. By elucidating mechano-metabolic interactions occurring at the tumor-host interface, these results will inform the development of innovative mechano-metabolic reprogramming treatment strategies to improve breast cancer patient survival.

biochemistry↗

bioRxiv2024

Multi-Niche Human Bone Marrow On-A-Chip for Studying the Interactions of Adoptive CAR-T Cell Therapies with Multiple Myeloma

Multiple myeloma (MM), a cancer of bone marrow plasma cells, is the second-most common hematological malignancy. However, despite immunotherapies like chimeric antigen receptor (CAR)-T cells, relapse is nearly universal. The bone marrow (BM) microenvironment influences how MM cells survive, proliferate, and resist treatment. Yet, it is unclear which BM niches give rise to MM pathophysiology. Here, we present a 3D microvascularized culture system, which models the endosteal and perivascular bone marrow niches, allowing us to study MM-stroma interactions in the BM niche and model responses to therapeutic CAR-T cells. We demonstrated the prolonged survival of cell line-based and patient-derived multiple myeloma cells within our in vitro system and successfully flowed in donor-matched CAR-T cells. We then measured T cell survival, differentiation, and cytotoxicity against MM cells using a variety of analysis techniques. Our MM-on-a-chip system could elucidate the role of the BM microenvironment in MM survival and therapeutic evasion and inform the rational design of next-generation therapeutics. TEASERA multiple myeloma model can study why the disease is still challenging to treat despite options that work well in other cancers.

cancer biology↗