A Bioengineered Model of Human Pancreatic Cancer to Study Responses to Therapy and Tumour Immunity

Verena Jasmin Kast

AutorIn

Verena Jasmin Kast

Titel

A Bioengineered Model of Human Pancreatic Cancer to Study Responses to Therapy and Tumour Immunity

Zitierfähige Url:

https://nbn-resolving.org/urn:nbn:de:bsz:14-qucosa2-1025821

Erstveröffentlichung

2026

Datum der Einreichung

11.02.2025

Datum der Verteidigung

14.01.2026

Abstract (EN)

The prognosis for pancreatic ductal adenocarcinoma (PDAC) patients is dismal, and inherent treatment resistance is a significant challenge. Responses to standard-of-care chemotherapies are disappointing, and therapies harnessing the immune system have been ineffective in clinical trials. In PDAC, response to therapy is dictated by the tumour microenvironment (TME), building desmoplastic and immunosuppressive barriers, preventing efficient drug delivery. Pre-clinical models of the pancreatic TME recapitulating the cellular, biochemical, and biomechanical characteristics of the immunosuppressive milieu are promising, allowing immunotherapeutic drug testing and immuno-oncology studies. There is, however, a lack of sophisticated models that capture critical pathophysiological elements of tumour tissues, impeding the development of therapeutic strategies and limiting our understanding of mechanisms driving tumour immunity. Current pre-clinical immuno-oncology research is primarily performed in immunocompromised murine models or three-dimensional organoids embedded in the disease-defined basement membrane extract Matrigel, inadequately representing the PDAC TME. Consequently, tissue engineering technologies have produced innovative bioengineered approaches that more accurately replicate the complexity of the primary tumour niche, metastatic lesions, or cellular responses to drug treatment. Based on a rational design approach, these platforms allow the precise recapitulation of tailored tissue states and exquisite control over biomechanical properties and cellular growth. For example, highly defined hydrogel systems based on matrix metalloproteinase (MMP)-sensitive four-armed star-shaped poly(ethylene glycol) (star-PEG)-heparin have emerged as powerful tools for modelling cancer. Biophysical and biochemical features can be precisely adjusted, the growth of both cancer and stromal cells over prolonged periods is supported, and cell-cell and cell-extracellular matrix (ECM) interaction can be established, all critical design aspects for mimicking the PDAC TME. However, the suitability of star-PEG-heparin hydrogel constructs as pre-clinical in vitro platforms for immunomodulatory drug testing and exploring mechanisms of tumour immunity in PDAC has not yet been tested. As such, this dissertation aimed to develop and explore the potential of MMP-sensitive star-PEG-heparin constructs as a hydrogel matrix to recapitulate the TME of PDAC, assess responses towards immunomodulatory therapy and identify novel mechanisms of immunosuppression. To model aspects of the cellular complexity of tumour tissues, pancreatic cancer cells co-cultured with patient-derived cancer-associated fibroblasts (CAFs) and peripheral blood mononuclear cells (PBMCs) were grown embedded in the hydrogels. In-depth mechanical characterisation of hydrogel constructs revealed that the entire tissue stiffness spectrum observed across PDAC patients can be recapitulated. The tailored adjustment of cell-adhesion sites enabled precise control over cellular growth, and embedded cells actively remodelled the matrix within 14 days of 3D cell culture. The cultures benefited from the co-culture approaches with CAFs and PBMCs, which led to increased spheroid formation, higher cell metabolic activities, and ECM accumulation. Remarkably, embedded PBMCs differentiated into CD68+ macrophages, indicating tumour-immune cell interactions. Different drug regimens were tested to assess the model's suitability as an in vitro drug testing platform for immunomodulatory therapies. The study found that combining the CD11b agonist ADH-503 with immune checkpoint blockade and standard-of-care chemotherapies resulted in the most significant responses, determined by the highest reduction in metabolic activity and proliferation, immunomodulation, and changes in immunosuppressive cytokine secretion. Side-by-side with the development of more efficient and predictive drug testing platforms, strategies targeting tumour immunity to improve anti-cancer therapies in PDAC remain an unmet frontier. In PDAC, numerous dysregulated proteases are present, of which kallikrein-related peptidases (KLKs) have received notable consideration. Despite improvements in recognising individual KLKs for their pro-tumorigenic activities, their specific roles are largely undefined. However, it is increasingly appreciated that KLKs can control tumour immunity. Since PDAC is characterised by a substantial immunosuppressive milieu in which KLK6 is highly dysregulated, correlating with poor patient outcomes, this dissertation postulated that KLK6 contributes to tumour immunity. Here, the previously developed PDAC model was adopted to recapitulate elements of the 3D space in which proteases operate. Coupled with CRISPR/Cas9, the study found that KLK6 favours cancer growth. RNA sequencing (RNAseq) of hydrogel constructs revealed that KLK6 affects genes associated with antigen presentation and neutrophil recruitment, critical immune suppressors in PDAC. In patients, high KLK6 expression positively correlates with neutrophil-recruiting chemokines. Neutrophil recruitment was recapitulated in vitro, which was lower in the absence of KLK6. Incubating neutrophils in conditioned KLK6 knockout (KO) media led to a decreased immunosuppressive phenotype, indicated by reduced arginase 1 (Arg1) expression, a marker of T cell suppression. RNAseq revealed that KLK6 impairs genes associated with immune checkpoint inhibition, which led to a reduced response to programmed cell death protein 1 (PD-1) checkpoint blockade in vitro. Accordingly, the study identified KLK6 as a potential additional drug target as it impacts neutrophil recruitment, immunosuppression, and response to anti-PD-1 therapy in a tissue-engineered in vitro model of PDAC.

Verweis

Link: https://www.nature.com/articles/s41578-023-00535-3
Biomaterial-based platforms for tumour tissue engineering
DOI: 10.1038/s41578-023-00535-3

A Tumor Microenvironment Model of Pancreatic Cancer to Elucidate Responses toward Immunotherapy
DOI: 10.1002/adhm.202201907

A biomaterial-based platform of pancreatic cancer reveals kallikrein-related peptidase 6 (KLK6) as a mediator of neutrophil recruitment and immunosuppression
DOI: 10.1016/j.biomaterials.2025.123456

Freie Schlagwörter (EN)