Degree
Doctor of Philosophy (PhD)
Department
Biological and Agricultural Engineering
Document Type
Dissertation
Abstract
Triple-negative breast cancer (TNBC) is an aggressive subtype accounting for 10-15% of breast cancers. Because TNBC lacks estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2) receptors, no targeted therapies exist, leaving chemotherapy as the primary treatment. Fewer than one-third of patients respond due to de novo or acquired drug resistance. These resistance mechanisms are shaped by the surrounding microenvironment, highlighting the need for in vitro models incorporating extracellular components. The extracellular matrix (ECM) plays a major role in TNBC progression and treatment response, yet standard models fail to replicate TNBC ECM biochemical and mechanical cues, limiting translation of novel therapies to the clinic.
To address this limitation, decellularized ECM-spheroids (dECM-spheroids) were developed as a physiologically relevant TNBC platform. Molecular composition, fiber architecture, and mechanical properties of decellularized metaplastic TNBC tumor ECM were characterized and compared with matched normal breast ECM. Metaplastic TNBC ECM showed altered protein expression, including increases in FN1, POSTN, TNC, and MFAP2. Decellularized tumor tissue had significantly larger pore size but no change in stiffness relative to normal breast tissue, whereas tumor-adjacent tissue was significantly stiffer. Decellularized tissue was lyophilized and cryomilled into a micronized ECM powder for spheroid fabrication.
The TNBC cell line MDA‑MB‑231 was combined with breast‑ or tumor‑derived decellularized ECM at varying ECM concentrations. RNA sequencing was performed on low-density (10 µg/mL) and high-density (20 µg/mL) spheroids to evaluate ECM-dependent transcriptional changes relative to ECM-free spheroids. Incorporating TNBC cells within ECM activated genes associated with Hippo signaling, Integrin signaling, MAPK signaling, ERBB signaling, focal adhesion signaling, actin cytoskeleton signaling, TGFβ signaling, and TNF signaling, suggesting these transcriptional changes are tied to ECM-regulated pathways, although direct protein-level expression was not assessed. ECM concentration influenced response magnitude, with high-density spheroids producing more differentially expressed genes and stronger pathway enrichment.
These findings demonstrate that incorporating solubilized decellularized ECM into spheroids, regardless of concentration or source, drives ECM-regulated transcriptional change. By restoring ECM-dependent transcriptional programs and enabling evaluation of native breast and tumor ECM effects on TNBC cellular response, dECM-spheroids provide a platform that more closely reflects the native tumor microenvironment than scaffold-free models.
Date
10-5-2026
Recommended Citation
Savoie, Jonathan J., "Fabrication of Human Breast-Derived Matrix Spheroids to Enhance Physiological Relevance for Triple-Negative Breast Cancer Investigations" (2026). LSU Doctoral Dissertations. 7208.
https://repository.lsu.edu/gradschool_dissertations/7208
Committee Chair
Monroe, William Todd
LSU Acknowledgement
1
LSU Accessibility Acknowledgment
1