Chemoradiotherapy screening in a novel biomimetic polymer based pancreatic cancer model

Dual-crosslinking gelatin-hyaluronic acid methacrylate based biomimetic PDAC desmoplastic niche enhances tumor-associated macrophages recruitment and M2-like polarization

The tumor microenvironment (TME) of pancreatic ductal adenocarcinoma (PDAC) is characterized by deposition of desmoplastic matrix (including collagen and hyaluronic acid). And the interactions between tumor-associated macrophages (TAMs) and tumor cells play a crucial role in progression of PDAC. Hence, the appropriate model of tumor cell-macrophage interaction within the unique PDAC TME is of significantly important. To this end, a 3D tumor niche based on dual-crosslinking gelatin methacrylate and hyaluronic acid methacrylate hydrogels was constructed to simulate the desmoplastic tumor matrix with matching compressive modulus and composition. The bionic 3D tumor niche creates an immunosuppressive microenvironment characterized by the downregulation of M1 markers and upregulation of M2 markers in TAMs. Mechanistically, RNA-seq analysis revealed that the PI3K-AKT signaling pathway might modulate the phenotypic balance and recruitment of macrophages through regulating SELE and VCAM-1. Furthermore, GO and GSEA revealed the biological process of leukocyte migration and the activation of cytokine-associated signaling were involved. Finally, the 3D tumor-macrophage niches with three different ratios were fabricated which displayed increased M2-like polarization and stemness. The utilization of the 3D tumor niche has the potential to provide a more accurate investigation of the interplay between PDAC tumor cells and macrophages within an in vivo setting.

Chemotherapy Assessment in Advanced Multicellular 3D Models of Pancreatic Cancer: Unravelling the Importance of Spatiotemporal Mimicry of the Tumor Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is a challenge for global health with very low survival rate and high therapeutic resistance. Hence, advanced preclinical models for treatment screening are of paramount importance. Herein, chemotherapeutic (gemcitabine) assessment on novel (polyurethane) scaffold-based spatially advanced 3D multicellular PDAC models is carried out. Through comprehensive image-based analysis at the protein level, and expression analysis at the mRNA level, the importance of stromal cells is confirmed, primarily activated stellate cells in the chemoresistance of PDAC cells within the models. Furthermore, it is demonstrated that, in addition to the presence of activated stellate cells, the spatial architecture of the scaffolds, i.e., segregation/compartmentalization of the cancer and stromal zones, affect the cellular evolution and is necessary for the development of chemoresistance. These results highlight that, further to multicellularity, mapping the tumor structure/architecture and zonal complexity in 3D cancer models is important for better mimicry of the in vivo therapeutic response.

Scaffold-based 3D cell culture models in cancer research

Three-dimensional (3D) cell cultures have emerged as valuable tools in cancer research, offering significant advantages over traditional two-dimensional (2D) cell culture systems. In 3D cell cultures, cancer cells are grown in an environment that more closely mimics the 3D architecture and complexity of in vivo tumors. This approach has revolutionized cancer research by providing a more accurate representation of the tumor microenvironment (TME) and enabling the study of tumor behavior and response to therapies in a more physiologically relevant context. One of the key benefits of 3D cell culture in cancer research is the ability to recapitulate the complex interactions between cancer cells and their surrounding stroma. Tumors consist not only of cancer cells but also various other cell types, including stromal cells, immune cells, and blood vessels. These models bridge traditional 2D cell cultures and animal models, offering a cost-effective, scalable, and ethical alternative for preclinical research. As the field advances, 3D cell cultures are poised to play a pivotal role in understanding cancer biology and accelerating the development of effective anticancer therapies. This review article highlights the key advantages of 3D cell cultures, progress in the most common scaffold-based culturing techniques, pertinent literature on their applications in cancer research, and the ongoing challenges.

Polyurethane scaffold-based 3D lung cancer model recapitulates in vivo tumor biological behavior for nanoparticulate drug screening

Lung cancer is the leading cause of cancer mortality worldwide. Preclinical studies in lung cancer hold the promise of screening for effective antitumor agents, but mechanistic studies and drug discovery based on 2D cell models have a high failure rate in getting to the clinic. Thus, there is an urgent need to explore more reliable and effective in vitro lung cancer models. Here, we prepared a series of three-dimensional (3D) waterborne biodegradable polyurethane (WBPU) scaffolds as substrates to establish biomimetic tumor models in vitro. These 3D WBPU scaffolds were porous and could absorb large amounts of free water, facilitating the exchange of substances (nutrients and metabolic waste) and cell growth. The scaffolds at wet state could simulate the mechanics (elastic modulus ∼1.9 kPa) and morphology (porous structures) of lung tissue and exhibit good biocompatibility. A549 lung cancer cells showed adherent growth pattern and rapidly formed 3D spheroids on WBPU scaffolds. Our results showed that the scaffold-based 3D lung cancer model promoted the expression of anti-apoptotic and epithelial-mesenchymal transition-related genes, giving it a more moderate growth and adhesion pattern compared to 2D cells. In addition, WBPU scaffold-established 3D lung cancer model revealed a closer expression of proteins to in vivo tumor, including tumor stem cell markers, cell proliferation, apoptosis, invasion and tumor resistance proteins. Based on these features, we further demonstrated that the 3D lung cancer model established by the WBPU scaffold was very similar to the in vivo tumor in terms of both resistance and tolerance to nanoparticulate drugs. Taken together, WBPU scaffold-based lung cancer model could better mimic the growth, microenvironment and drug response of tumor in vivo. This emerging 3D culture system holds promise to shorten the formulation cycle of individualized treatments and reduce the use of animals while providing valid research data for clinical trials.

Single-Cell Lipidomics Using Analytical Flow LC-MS Characterizes the Response to Chemotherapy in Cultured Pancreatic Cancer Cells

In this work, we demonstrate the development and first application of nanocapillary sampling followed by analytical flow liquid chromatography-mass spectrometry for single-cell lipidomics. Around 260 lipids were tentatively identified in a single cell, demonstrating remarkable sensitivity. Human pancreatic ductal adenocarcinoma cells (PANC-1) treated with the chemotherapeutic drug gemcitabine can be distinguished from controls solely on the basis of their single-cell lipid profiles. Notably, the relative abundance of LPC(0:0/16:0) was significantly affected in gemcitabine-treated cells, in agreement with previous work in bulk. This work serves as a proof of concept that live cells can be sampled selectively and then characterized using automated and widely available analytical workflows, providing biologically relevant outputs.

Enhanced effect of X-rays in the presence of a static magnetic field within a 3D pancreatic cancer model

OBJECTIVE

To evaluate the impact of static magnetic field (SMF) presence on the radiation response of pancreatic cancer cells in polyurethane-based highly macro-porous scaffolds in hypoxic (1% O2) and normoxic (21% O2) conditions, towards understanding MR-guided radiotherapy, shedding light on the potential interaction phenomenon between SMF and radiation in a three-dimensional (3D) microenvironment.

METHODS

Pancreatic cancer cells (PANC-1, ASPC-1) were seeded into fibronectin-coated highly porous polyethene scaffolds for biomimicry and cultured for 4 weeks in in vitro normoxia (21% O2) followed by a 2-day exposure to either in vitro hypoxia (1% O2) or maintenance in in vitro normoxia (21% O2). The samples were then irradiated with 6 MV photons in the presence or absence of a 1.5 T field. Thereafter, in situ post-radiation monitoring (1 and 7 days post-irradiation treatment) took place via quantification of (i) live dead and (ii) apoptotic profiles.

RESULTS

We report: (i) pancreatic ductal adenocarcinoma hypoxia-associated radioprotection, in line with our previous findings, (ii) an enhanced effect of radiation in the presence of SMFin in vitro hypoxia (1% O2) for both short- (1 day) and long-term (7 days) post -radiation analysis and (iii) an enhanced effect of radiation in the presence of SMF in in vitro normoxia (21% O2) for long-term (7 days) post-radiation analysis within a 3D pancreatic cancer model.

CONCLUSION

With limited understanding of the potential interaction phenomenon between SMF and radiation, this 3D system allows combination evaluation for a cancer in which the role of radiotherapy is still evolving.

ADVANCES IN KNOWLEDGE

This study examined the use of a 3D model to investigate MR-guided radiotherapy in a hypoxic microenvironment, indicating that this could be a useful platform to further understanding of SMF influence on radiation.

A Step-by-Step Methodological Guide for Developing Zonal Multicellular Scaffold-Based Pancreatic Cancer Models

The tumor microenvironment (TME), a complex heterogeneous mixture of various cellular, physical, and biochemical components and signals, is a major player in the process of tumor growth and its response to therapeutic methods. In vitro 2D monocellular cancer models are unable to mimic the complex in vivo characteristics of cancer TME involving cellular heterogeneity, presence of extracellular matrix (ECM) proteins, as well as spatial orientation and organization of different cell types forming the TME. In vivo animal-based studies have ethical concerns, are expensive and time-consuming, and involve models of non-human species. In vitro 3D models are capable of tiding over several issues associated with both 2D in vitro and in vivo animal models. We have recently developed a novel zonal multicellular 3D in vitro model for pancreatic cancer involving cancer cells, endothelial cells, and pancreatic stellate cells. Our model (i) can provide long-term culture (up to 4 weeks), (ii) can control the ECM biochemical configuration in a cell specific manner, (iii) shows large amounts of collagen secretion by the stellate cells mimicking desmoplasia, and (iv) expresses cell-specific markers throughout the whole culture period. This chapter describes the experimental methodology to form our hybrid multicellular 3D model for pancreatic ductal adenocarcinoma, including the immunofluorescence staining on the cell culture.

The Development of a Three-Dimensional Platform for Patient-Derived Ovarian Cancer Tissue Models: A Systematic Literature Review

There is an unmet biomedical need for ex vivo tumour models that would predict drug responses and in turn help determine treatment regimens and potentially predict resistance before clinical studies. Research has shown that three dimensional models of ovarian cancer (OvCa) are more realistic than two dimensional in vitro systems as they are able to capture patient in vivo conditions in more accurate manner. The vast majority of studies aiming to recapitulate the ovarian tumour morphology, behaviors, and study chemotherapy responses have been using ovarian cancer cell lines. However, despite the advantages of utilising cancer cell lines to set up a platform, they are not as informative as systems applying patient derived cells, as cell lines are not able to recapitulate differences between each individual patient characteristics. In this review we discussed the most recent advances in the creation of 3D ovarian cancer models that have used patient derived material, the challenges to overcome and future applications.

Current strategies with implementation of three-dimensional cell culture: the challenge of quantification

From growing cells in spheroids to arranging them on complex engineered scaffolds, three-dimensional cell culture protocols are rapidly expanding and diversifying. While these systems may often improve the physiological relevance of cell culture models, they come with technical challenges, as many of the analytical methods used to characterize traditional two-dimensional (2D) cells must be modified or replaced to be effective. Here we review the advantages and limitations of quantification methods based either on biochemical measurements or microscopy imaging. We focus on the most basic of parameters that one may want to measure, the number of cells. Precise determination of this number is essential for many analytical techniques where measured quantities are only meaningful when normalized to the number of cells (e.g. cytochrome p450 enzyme activity). Thus, accurate measurement of cell number is often a prerequisite to allowing comparisons across different conditions (culturing conditions or drug and treatment screening) or between cells in different spatial states. We note that this issue is often neglected in the literature with little or no information given regarding how normalization was performed, we highlight the pitfalls and complications of quantification and call for more accurate reporting to improve reproducibility.

Pericytes' Circadian Clock Affects Endothelial Cells' Synchronization and Angiogenesis in a 3D Tissue Engineered Scaffold

Angiogenesis, the formation of new capillaries from existing ones, is a fundamental process in regenerative medicine and tissue engineering. While it is known to be affected by circadian rhythms in vivo, its peripheral regulation within the vasculature and the role it performs in regulating the interplay between vascular cells have not yet been investigated. Peripheral clocks within the vasculature have been described in the endothelium and in smooth muscle cells. However, to date, scarce evidence has been presented regarding pericytes, a perivascular cell population deeply involved in the regulation of angiogenesis and vessel maturation, as well as endothelial function and homeostasis. More crucially, pericytes are also a promising source of cells for cell therapy and tissue engineering. Here, we established that human primary pericytes express key circadian genes and proteins in a rhythmic fashion upon synchronization. Conversely, we did not detect the same patterns in cultured endothelial cells. In line with these results, pericytes' viability was disproportionately affected by circadian cycle disruption, as compared to endothelial cells. Interestingly, endothelial cells' rhythm could be induced following exposure to synchronized pericytes in a contact co-culture. We propose that this mechanism could be linked to the altered release/uptake pattern of lactate, a known mediator of cell-cell interaction which was specifically altered in pericytes by the knockout of the key circadian regulator Bmal1. In an angiogenesis assay, the maturation of vessel-like structures was affected only when both endothelial cells and pericytes did not express Bmal1, indicating a compensation system. In a 3D tissue engineering scaffold, a synchronized clock supported a more structured organization of cells around the scaffold pores, and a maturation of vascular structures. Our results demonstrate that pericytes play a critical role in regulating the circadian rhythms in endothelial cells, and that silencing this system disproportionately affects their pro-angiogenic function. Particularly, in the context of tissue engineering and regenerative medicine, considering the effect of circadian rhythms may be critical for the development of mature vascular structures and to obtain the maximal reparative effect.

A Systematic Comparative Assessment of the Response of Ovarian Cancer Cells to the Chemotherapeutic Cisplatin in 3D Models of Various Structural and Biochemical Configurations-Does One Model Type Fit All?

Simple Summary

Epithelial Ovarian Cancer is considered to be a ‘silent killer’ and a challenge for gynaecological health across the world due to its asymptotic nature in the early stages, its late-stage diagnosis, high recurrence rate and resistance to currently available treatment methods (chemotherapy). These disheartening figures highlight the need for extensive in vitro studies to better understand this disease. A number of in vitro 3D models are currently available to aid in the study of ovarian cancer and its response to therapeutic methods. In this work, we report, for the first time, a comprehensive comparative study of three widely used 3D in vitro models for ovarian cancer, along with chemotherapy assessment of primary and metastatic cells. Our study highlights the importance of selecting an appropriate 3D in vitro platform, which is based on multiple factors including the origin of cells used, experimental time period and experimental design, even for one specific disease.

Abstract

Epithelial Ovarian Cancer (EOC) is a silent, deadly and aggressive gynaecological disease with a relatively low survival rate. This has been attributed, to some extent, to EOC’s high recurrence rate and resistance to currently available platinum-based chemotherapeutic treatment methods. Multiple groups have studied and reported the effect of chemotherapeutic agents on various EOC 3D in vitro models. However, there are very few studies wherein a direct comparative study has been carried out between the different in vitro 3D models of EOC and the effect of chemotherapy within them. Herein, we report, for the first time, a direct comprehensive systematic comparative study of three different 3D in vitro platforms, namely (i) spheroids, (ii) synthetic PeptiGels/hydrogels of various chemical configurations and (iii) polymeric scaffolds with coatings of various extracellular matrices (ECMs) on the cell growth and response to the chemotherapeutic (Cisplatin) for ovary-derived (A2780) and metastatic (SK-OV-3) EOC cell lines. We report that all three 3D models are able to support the growth of EOC, but for different time periods (varying from 7 days to 4 weeks). We have also reported that chemoresistance to Cisplatin, in vitro, observed especially for metastatic EOC cells, is platform-dependent, in terms of both the structural and biochemical composition of the model/platform. Our study highlights the importance of selecting an appropriate 3D platform for in vitro tumour model development. We have demonstrated that the selection of the best platform for producing in vitro tumour models depends on the cancer/cell type, the experimental time period and the application for which the model is intended.

On the Evaluation of a Novel Hypoxic 3D Pancreatic Cancer Model as a Tool for Radiotherapy Treatment Screening

Tissue engineering is evolving to mimic intricate ecosystems of tumour microenvironments (TME) to more readily map realistic in vivo niches of cancerous tissues. Such advanced cancer tissue models enable more accurate preclinical assessment of treatment strategies. Pancreatic cancer is a dangerous disease with high treatment resistance that is directly associated with a highly complex TME. More specifically, the pancreatic cancer TME includes (i) complex structure and complex extracellular matrix (ECM) protein composition; (ii) diverse cell populations (e.g., stellate cells), cancer associated fibroblasts, endothelial cells, which interact with the cancer cells and promote resistance to treatment and metastasis; (iii) accumulation of high amounts of (ECM), which leads to the creation of a fibrotic/desmoplastic reaction around the tumour; and (iv) heterogeneous environmental gradients such as hypoxia, which result from vessel collapse and stiffness increase in the fibrotic/desmoplastic area of the TME. These unique hallmarks are not effectively recapitulated in traditional preclinical research despite radiotherapeutic resistance being largely connected to them. Herein, we investigate, for the first time, the impact of in vitro hypoxia (5% O2) on the radiotherapy treatment response of pancreatic cancer cells (PANC-1) in a novel polymer (polyurethane) based highly macroporous scaffold that was surface modified with proteins (fibronectin) for ECM mimicry. More specifically, PANC-1 cells were seeded in fibronectin coated macroporous scaffolds and were cultured for four weeks in in vitro normoxia (21% O2), followed by a two day exposure to either in vitro hypoxia (5% O2) or maintenance in in vitro normoxia. Thereafter, in situ post-radiation monitoring (one day, three days, seven days post-irradiation) of the 3D cell cultures took place via quantification of (i) live/dead and apoptotic profiles and (ii) ECM (collagen-I) and HIF-1a secretion by the cancer cells. Our results showed increased post-radiation viability, reduced apoptosis, and increased collagen-I and HIF-1a secretion in in vitro hypoxia compared to normoxic cultures, revealing hypoxia-induced radioprotection. Overall, this study employed a low cost, animal free model enabling (i) the possibility of long-term in vitro hypoxic 3D cell culture for pancreatic cancer, and (ii) in vitro hypoxia associated PDAC radio-protection development. Our novel platform for radiation treatment screening can be used for long-term in vitro post-treatment observations as well as for fractionated radiotherapy treatment.

Towards More Predictive, Physiological and Animal-free In Vitro Models: Advances in Cell and Tissue Culture 2020 Conference Proceedings

Experimental systems that faithfully replicate human physiology at cellular, tissue and organ level are crucial to the development of efficacious and safe therapies with high success rates and low cost. The development of such systems is challenging and requires skills, expertise and inputs from a diverse range of experts, such as biologists, physicists, engineers, clinicians and regulatory bodies. Kirkstall Limited, a biotechnology company based in York, UK, organised the annual conference, Advances in Cell and Tissue Culture (ACTC), which brought together people having a variety of expertise and interests, to present and discuss the latest developments in the field of cell and tissue culture and in vitro modelling. The conference has also been influential in engaging animal welfare organisations in the promotion of research, collaborative projects and funding opportunities. This report describes the proceedings of the latest ACTC conference, which was held virtually on 30th September and 1st October 2020, and included sessions on in vitro models in the following areas: advanced skin and respiratory models, neurological disease, cancer research, advanced models including 3-D, fluid flow and co-cultures, diabetes and other age-related disorders, and animal-free research. The roundtable session on the second day was very interactive and drew huge interest, with intriguing discussion taking place among all participants on the theme of replacement of animal models of disease.

Novel Anticancer and Treatment Sensitizing Compounds against Pancreatic Cancer

The isolation of chemical compounds from natural origins for medical application has played an important role in modern medicine with a range of novel treatments having emerged from various natural forms over the past decades. Natural compounds have been exploited for their antioxidant, antimicrobial and antitumor capabilities. Specifically, 60% of today's anticancer drugs originate from natural sources. Moreover, the combination of synthetic and natural treatments has shown applications for (i) reduced side effects, (ii) treatment sensitization and (iii) reduction in treatment resistance. This review aims to collate novel and natural compounds that are being explored for their preclinical anticancer, chemosensitizing and radiosensitizing effects on Pancreatic Ductal Adenocarcinoma (PDAC), which is a lethal disease with current treatments being inefficient and causing serve side effects. Two key points are highlighted by this work: (i) the availability of a range of natural compounds for potentially new therapeutic approaches for PDAC, (ii) potential synergetic impact of natural compounds with advanced chemo- and radio-therapeutic modalities for PDAC.

3d tissue models as tools for radiotherapy screening for pancreatic cancer

The efficiency of radiotherapy treatment regimes varies from tumour to tumour and from patient to patient but it is generally highly influenced by the tumour microenvironment (TME). The TME can be described as a heterogeneous composition of biological, biophysical, biomechanical and biochemical milieus that influence the tumour survival and its' response to treatment. Preclinical research faces challenges in the replication of these in vivo milieus for predictable treatment response studies. 2D cell culture is a traditional, simplistic and cost-effective approach to culture cells in vitro, however, the nature of the system fails to recapitulate important features of the TME such as structure, cell-cell and cell-matrix interactions. At the same time, the traditional use of animals (Xenografts) in cancer research allows realistic in vivo architecture, however foreign physiology, limited heterogeneity and reduced tumour mutation rates impairs relevance to humans. Furthermore, animal research is very time consuming and costly. Tissue engineering is advancing as a promising biomimetic approach, producing 3D models that capture structural, biophysical, biochemical and biomechanical features, therefore, facilitating more realistic treatment response studies for further clinical application. However, currently, the application of 3D models for radiation response studies is an understudied area of research, especially for pancreatic ductal adenocarcinoma (PDAC), a cancer with a notoriously complex microenvironment. At the same time, specific novel and/or more enhanced radiotherapy tumour-targeting techniques such as MRI-guided radiotherapy and proton therapy are emerging to more effectively target pancreatic cancer cells. However, these emerging technologies may have different biological effectiveness as compared to established photon-based radiotherapy. For example, for MRI-guided radiotherapy, the novel use of static magnetic fields (SMF) during radiation delivery is understudied and not fully understood. Thus, reliable biomimetic platforms to test new radiation delivery strategies are required to more accurately predict in vivo responses. Here, we aim to collate current 3D models for radiation response studies of PDAC, identifying the state of the art and outlines knowledge gaps. Overall, this review paper highlights the need for further research on the use of 3D models for pre-clinical radiotherapy screening including (i) 3D (re)-modeling of the PDAC hypoxic TME to allow for late effects of ionising radiation (ii) the screening of novel radiotherapy approaches and their combinations as well as (iii) a universally accepted 3D-model image quantification method for evaluating TME components in situ that would facilitate accurate post-treatment(s) quantitative comparisons.

A Novel Scaffold-Based Hybrid Multicellular Model for Pancreatic Ductal Adenocarcinoma-Toward a Better Mimicry of the in vivo Tumor Microenvironment

With a very low survival rate, pancreatic ductal adenocarcinoma (PDAC) is a deadly disease. This has been primarily attributed to (i) its late diagnosis and (ii) its high resistance to current treatment methods. The latter specifically requires the development of robust, realistic in vitro models of PDAC, capable of accurately mimicking the in vivo tumor niche. Advancements in the field of tissue engineering (TE) have helped the development of such models for PDAC. Herein, we report for the first time a novel hybrid, polyurethane (PU) scaffold-based, long-term, multicellular (tri-culture) model of pancreatic cancer involving cancer cells, endothelial cells, and stellate cells. Recognizing the importance of ECM proteins for optimal growth of different cell types, the model consists of two different zones/compartments: an inner tumor compartment consisting of cancer cells [fibronectin (FN)-coated] and a surrounding stromal compartment consisting of stellate and endothelial cells [collagen I (COL)-coated]. Our developed novel hybrid, tri-culture model supports the proliferation of all different cell types for 35 days (5 weeks), which is the longest reported timeframe in vitro. Furthermore, the hybrid model showed extensive COL production by the cells, mimicking desmoplasia, one of PDAC's hallmark features. Fibril alignment of the stellate cells was observed, which attested to their activated state. All three cell types expressed various cell-specific markers within the scaffolds, throughout the culture period and showed cellular migration between the two zones of the hybrid scaffold. Our novel model has great potential as a low-cost tool for in vitro studies of PDAC, as well as for treatment screening.