ECM Composition and Rheology Regulate Growth, Motility, and Response to Photodynamic Therapy in 3D Models of Pancreatic Ductal Adenocarcinoma

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is characterized by prominent stromal involvement, which plays complex roles in regulating tumor growth and therapeutic response. The extracellular matrix (ECM)-rich PDAC stroma has been implicated as a barrier to drug penetration, though stromal depletion strategies have had mixed clinical success. It remains less clear how interactions with ECM, acting as a biophysical regulator of phenotype, not only a barrier to drug perfusion, regulate susceptibilities and resistance to specific therapies. In this context, an integrative approach is used to evaluate invasive behavior and motility in rheologically-characterized ECM as determinants of chemotherapy and photodynamic therapy (PDT) responses. We show that in 3D cultures with ECM conditions that promote invasive progression, response to PDT is markedly enhanced in the most motile ECM-infiltrating populations while the same cells exhibit chemoresistance. Conversely, drug-resistant sublines with enhanced invasive potential were generated to compare differential treatment response in identical ECM conditions, monitored by particle tracking microrheology measurements of matrix remodeling. In both scenarios, ECM-infiltrating cell populations exhibit increased sensitivity to PDT, whether invasion is consequent to selection of chemoresistance, or whether chemoresistance is correlated with acquisition of invasive behavior. However, while ECM-invading, chemoresistant cells exhibit mesenchymal phenotype, induction of EMT in monolayers without ECM was not sufficient to enhance PDT sensitivity, yet does impart chemoresistance as expected. In addition to containing platform development with broader applicability to inform microenvironment-dependent therapeutics, these results reveal the efficacy of PDT for targeting the most aggressive, chemoresistant, invasive PDAC associated with dismal outcomes for this disease. Implications ECM-infiltrating and chemoresistant pancreatic tumor populations exhibit increased sensitivity to photodynamic therapy (PDT).

Modulation of Extracellular Matrix Rigidity Via Riboflavin‐mediated Photocrosslinking Regulates Invasive Motility and Treatment Response in a 3D Pancreatic Tumor Model

“…In the present study, we specifically leverage the capability to manipulate ECM rheology via photocrosslinking as a means to study how activation of invasive behavior impacts upon responsiveness to chemotherapy and photodynamic therapy (PDT). This line of investigation is motivated by our previous study using transplanted 3D pancreatic tumor spheroids in collagen and laminin‐rich ECM which promote and constrain, respectively, the invasive progression of peripheral cells of the primary spheroid into surrounding ECM . We found that ECM‐infiltrating cells exhibit increased sensitivity to PDT, yet decreased response to chemo, which is also consistent with evidence of increased epithelial–mesenchymal transition (EMT) in invading cells.…”

Mechanism of ECM-induced dormancy and chemoresistance in A549 human lung carcinoma cells

“…An increasing body of evidence suggests that the tumor microenvironment has a profound impact on cancer progression and therapeutic responses (1)(2)(3)(4). Extracellular matrix (ECM), a major component of the microenvironment, is composed of a combination of macromolecules (e.g.…”

Modeling Epidermal Growth Factor Inhibitor‐mediated Enhancement of Photodynamic Therapy Efficacy Using 3D Mesothelioma Cell Culture

“…Taken together, these results demonstrate that EGFR inhibition sensitizes MPM cells to PDT‐mediated apoptosis even with the addition of cell–cell and cell–matrix interactions, suggesting that this may be a potentially effective way to improve outcomes in patients undergoing eP/D‐pPDT. After attempting multiple potential methods of 3D culture for these MPM cell lines, we determined that Matrigel overlay was most effective and relevant to the defined experimental questions and found that MPM cells grow similarly to breast, ovarian, and pancreatic tumor cell lines in Matrigel . If larger 3D cultures are desired, Broaddus et al .…”

“…Compared to monolayer cultures, when MPM cells are grown as nonadherent spheroids in the absence of artificial ECM, they upregulate genes associated with the immune response and lymphocyte/cytokine stimulation while downregulating apoptosis-related genes (35). Survival signaling (including EGFR) and invasive behavior of cancer cells in the presence of ECM basement membrane also differs significantly from monolayer (36,37) and is often altered depending on the biochemical and biophysical properties of the ECM in contact with cells (25,38). Here, we found that, regardless of the biophysical composition of the ECM, EMP mesothelioma cells had increased phospho-EGFR after PDT (Fig.…”