bims-tuchim Biomed News
on Tumor-on-chip models
Issue of 2021–12–26
fiveteen papers selected by
Philipp Albrecht, Friedrich Schiller University



  1. Small Methods. 2021 May;5(5): e2001207
      Cancer-associated pancreatic stellate cells installed in periacinar/periductal regions are master players in generating the characteristic biophysical shield found in pancreatic ductal adenocarcinoma (PDAC). Recreating this unique PDAC stromal architecture and its desmoplastic microenvironment in vitro is key to discover innovative treatments. However, this still remains highly challenging to realize. Herein, organotypic 3D microtumors that recapitulate PDAC-stroma spatial bioarchitecture, as well as its biomolecular, metabolic, and desmoplastic signatures, are bioengineered. Such newly engineered platforms, termed stratified microenvironment spheroid models - STAMS - mimic the spatial stratification of cancer-stromal cells, exhibit a reproducible morphology and sub-millimeter size. In culture, 3D STAMS secrete the key molecular biomarkers found in human pancreatic cancer, namely TGF-β, FGF-2, IL-1β, and MMP-9, among others. This is accompanied by an extensive desmoplastic reaction where collagen and glycosaminoglycans (GAGs) de novo deposition is observed. These stratified models also recapitulate the resistance to various chemotherapeutics when compared to standard cancer-stroma random 3D models. Therapeutics resistance is further evidenced upon STAMS inclusion in a tumor extracellular matrix (ECM)-mimetic hydrogel matrix, reinforcing the importance of mimicking PDAC-stroma bioarchitectural features in vitro. The 3D STAMS technology represents a next generation of biomimetic testing platforms with improved potential for advancing high-throughput screening and preclinical validation of innovative pancreatic cancer therapies.
    Keywords:  ECM mimetic biomaterials; biomimetic 3D tumor models; pancreatic cancer; preclinical testing platforms; tumor microenvironment
    DOI:  https://doi.org/10.1002/smtd.202001207
  2. Int J Mol Sci. 2021 Dec 14. pii: 13408. [Epub ahead of print]22(24):
      Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related morbidity and mortality in the western world, with limited therapeutic strategies and dismal long-term survival. Cancer-associated fibroblasts (CAFs) are key components of the pancreatic tumor microenvironment, maintaining the extracellular matrix, while also being involved in intricate crosstalk with cancer cells and infiltrating immunocytes. Therefore, they are potential targets for developing therapeutic strategies against PDAC. However, recent studies have demonstrated significant heterogeneity in CAFs with respect to their origins, spatial distribution, and functional phenotypes within the PDAC tumor microenvironment. Therefore, it is imperative to understand and delineate this heterogeneity prior to targeting CAFs for PDAC therapy.
    Keywords:  CAF heterogeneity; apCAF; cancer-associated fibroblasts; iCAF; myCAF; pancreatic cancer; pancreatic ductal adenocarcinoma
    DOI:  https://doi.org/10.3390/ijms222413408
  3. Biosensors (Basel). 2021 Dec 10. pii: 509. [Epub ahead of print]11(12):
      Incorporation of extracellular matrix (ECM) and hydrogel in microfluidic 3D cell culture platforms is important to create a physiological microenvironment for cell morphogenesis and to establish 3D co-culture models by hydrogel compartmentalization. Here, we describe a simple and scalable ECM patterning method for microfluidic cell cultures by achieving hydrogel confinement due to the geometrical expansion of channel heights (stepped height features) and capillary burst valve (CBV) effects. We first demonstrate a sequential "pillar-free" hydrogel patterning to form adjacent hydrogel lanes in enclosed microfluidic devices, which can be further multiplexed with one to two stepped height features. Next, we developed a novel "spheroid-in-gel" culture device that integrates (1) an on-chip hanging drop spheroid culture and (2) a single "press-on" hydrogel confinement step for rapid ECM patterning in an open-channel microarray format. The initial formation of breast cancer (MCF-7) spheroids was achieved by hanging a drop culture on a patterned polydimethylsiloxane (PDMS) substrate. Single spheroids were then directly encapsulated on-chip in individual hydrogel islands at the same positions, thus, eliminating any manual spheroid handling and transferring steps. As a proof-of-concept to perform a spheroid co-culture, endothelial cell layer (HUVEC) was formed surrounding the spheroid-containing ECM region for drug testing studies. Overall, this developed stepped height-based hydrogel patterning method is simple to use in either enclosed microchannels or open surfaces and can be readily adapted for in-gel cultures of larger 3D cellular spheroids or microtissues.
    Keywords:  3D cell culture; hydrogel patterning; microarray; organ-on-a-chip; spheroid culture
    DOI:  https://doi.org/10.3390/bios11120509
  4. Cancers (Basel). 2021 Dec 08. pii: 6188. [Epub ahead of print]13(24):
      Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumors with a poor prognosis. A characteristic of PDAC is the formation of an immunosuppressive tumor microenvironment (TME) that facilitates bypassing of the immune surveillance. The TME consists of a desmoplastic stroma, largely composed of cancer-associated fibroblasts (CAFs), immunosuppressive immune cells, immunoregulatory soluble factors, neural network cells, and endothelial cells with complex interactions. PDAC develops from various precursor lesions such as pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasms (IPMN), mucinous cystic neoplasms (MCN), and possibly, atypical flat lesions (AFL). In this review, we focus on the composition of the TME in PanINs to reveal detailed insights into the complex restructuring of the TME at early time points in PDAC progression and to explore ways of modifying the TME to slow or even halt tumor progression.
    Keywords:  PDAC; PanIN; pancreatic cancer; tumor microenvironment
    DOI:  https://doi.org/10.3390/cancers13246188
  5. STAR Protoc. 2021 Dec 17. 2(4): 100984
      Despite colorectal cancer's (CRC) prevalence, its progression is not well understood. The microfluidic organ-on-chip (OOC) model described herein recreates the epithelial-endothelial tissue-tissue interface, fluid flow, and mechanical forces that exist in vivo , making it an attractive model to understand and ultimately disrupt CRC intravasation. This protocol provides step-by-step details for tumor cell seeding to create a CRC-on-chip model, chip effluent collection and analysis, and on-chip imaging to monitor tumor cell invasion within a more physiologically relevant microenvironment. For complete details on the use and execution of this protocol, please refer to Strelez et al. (2021).
    DOI:  https://doi.org/10.1016/j.xpro.2021.100984
  6. Cancer Discov. 2021 Dec 22.
      The microenvironment influences cancer transcriptional state and drives drug response.
    DOI:  https://doi.org/10.1158/2159-8290.CD-RW2021-181
  7. Micromachines (Basel). 2021 Dec 11. pii: 1542. [Epub ahead of print]12(12):
      A low-cost, versatile, and reconfigurable fluidic routing system and chip assembly have been fabricated and tested. The platform and its accessories were fabricated in-house without the need for costly and specialized equipment nor specific expertise. An agarose-based artificial membrane was integrated into the chips and employed to test the chip-to-chip communication in various configurations. Various chip assemblies were constructed and tested which demonstrate the versatile utility of the fluidic routing system that enables the custom design of the chip-to-chip communication and the possibility of fitting a variety of (organ-on-a-chip)-based biological models with multicell architectures. The reconfigurable chip assembly would enable selective linking/isolating the desired chip/compartment, hence allowing the study of the contribution of specific cell/tissue within the in vitro models.
    Keywords:  assembly; configurable; microfluidics; organ-on-a-chip
    DOI:  https://doi.org/10.3390/mi12121542
  8. Cancers (Basel). 2021 Dec 09. pii: 6204. [Epub ahead of print]13(24):
      Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy wherein a majority of patients present metastatic disease at diagnosis. Although the role of epithelial to mesenchymal transition (EMT), mediated by transforming growth factor beta (TGFβ), in imparting an aggressive phenotype to PDAC is well documented, the underlying biochemical pathway perturbations driving this behaviour have not been elucidated. We used high-resolution mass spectrometry (HRMS) based molecular phenotyping approach in order to delineate metabolic changes concomitant to TGFβ-induced EMT in pancreatic cancer cells. Strikingly, we observed robust changes in amino acid and energy metabolism that may contribute to tumor invasion and metastasis. Somewhat unexpectedly, TGFβ treatment resulted in an increase in intracellular levels of retinoic acid (RA) that in turn resulted in increased levels of extracellular matrix (ECM) proteins including fibronectin (FN) and collagen (COL1). These findings were further validated in plasma samples obtained from patients with resectable pancreatic cancer. Taken together, these observations provide novel insights into small molecule dysregulation that triggers a molecular cascade resulting in increased EMT-like changes in pancreatic cancer cells, a paradigm that can be potentially targeted for better clinical outcomes.
    Keywords:  9-cis retinoic acidPANC-1 cells; TGF beta; epithelial mesenchymal transition; pancreatic cancer; tumor microenvironment
    DOI:  https://doi.org/10.3390/cancers13246204
  9. Biosensors (Basel). 2021 Dec 09. pii: 506. [Epub ahead of print]11(12):
      Spheroid, a 3D aggregate of tumor cells in a spherical shape, has overcome the limitations of conventional 3D cell models to accurately mimic the in-vivo environment of a human body. The spheroids are cultured with other primary cells and embedded in collagen drops using hang drop plates and low-attachment well plates to construct a spheroid-hydrogel model that better mimics the cell-cell and cell-extracellular matrix (ECM) interactions. However, the conventional methods of culturing and embedding spheroids into ECM have several shortcomings. The procedure of transferring a single spheroid at a time by manual pipetting results in well-to-well variation and even loss or damage of the spheroid. Based on the previously introduced droplet contact-based spheroid transfer technique, we present a poly(dimethylsiloxane) and resin-based drop array chip and a pillar array chip with alignment stoppers, which enhances the alignment between the chips for uniform placement of spheroids. This method allows the facile and stable transfer of the spheroid array and even eliminates the need for a stereomicroscope while handling the cell models. The novel platform demonstrates a homogeneous and time-efficient construction and diverse analysis of an array of fibroblast-associated glioblastoma multiforme spheroids that are embedded in collagen.
    Keywords:  3D cell culture; droplet contact-based spheroid transfer; drug assay model; fibroblast; glioblastoma multiforme; spheroid invasion assay
    DOI:  https://doi.org/10.3390/bios11120506
  10. Biomater Sci. 2021 Dec 23.
      Despite the essential roles of natural killer (NK) cells in cancer treatment, the physical barrier and biological cues of the tumor microenvironment (TME) may induce NK cell dysfunction, causing their poor infiltration into tumors. The currently available two-dimensional (2D) cancer-NK co-culture systems hardly represent the characteristics of TME and are not suitable for tracking the infiltration of immune cells and assessing the efficacy of immunotherapy. This study aims to monitor NK-mediated cancer cell killing using a polymer thin film-based, 3D assay platform that contains highly tumorigenic cancer spheroids. A poly(cyclohexyl methacrylate) (pCHMA)-coated surface enables the generation of tumorigenic spheroids from pancreatic cancer patient-derived cancer cells, showing considerable amounts of extracellular matrix (ECM) proteins and cancer stem cell (CSC)-like characteristics. The 3D spheroid-based assay platform allows rapid discovery of a therapeutic agent for synergistic NK-mediated cytotoxicity through imaging-based high-content screening. In detail, the small molecule C19, known as a multi-epithelial-mesenchymal transition pathway inhibitor, is shown to enhance NK activation and infiltration via modulation of the ECM, resulting in synergistic cytotoxicity against cancer spheroids. This 3D biomimetic co-culture assay platform provides promising applications for predicting patient-specific responses to immunotherapy through advanced therapeutic combinations involving a chemical drug and immune cells.
    DOI:  https://doi.org/10.1039/d1bm01699g
  11. Front Immunol. 2021 ;12 790661
      Pancreatic ductal adenocarcinoma (PDAC) has a hypoxic and desmoplastic tumor microenvironment (TME), leading to treatment failure. We aimed to develop a prognostic classifier to evaluate hypoxia status and hypoxia-related molecular characteristics of PDAC. In this study, we classified PDAC into three clusters based on 16 known hypoxia-inducible factor 1 (HIF-1)-related genes. Nine differentially expressed genes were identified to construct an HIF-1 score system, whose predictive efficacy was evaluated. Furthermore, we investigated oncogenic pathways and immune-cell infiltration status of PDAC with different scores. The C-index of the HIF-1score system for OS prediction in the meta-PDAC cohort and the other two validation cohorts were 0.67, 0.63, and 0.65, respectively, indicating that it had a good predictive value for patient survival. Furthermore, the area under the curve (AUC) of the receiver operating characteristic (ROC) curve of the HIF-1α score system for predicting 1-, 3-, and 4-year OS indicated the HIF-1α score system had an optimal discrimination of prognostic prediction for PDAC. Importantly, our model showed superior predictive ability compared to previous hypoxia signatures. We also classified PDAC into HIF-1 scores of low, medium, and high groups. Then, we found high enrichment of glycolysis, mTORC1 signaling, and MYC signaling in the HIF-1 score high group, whereas the cGMP metabolic process was activated in the low score group. Of note, analysis of public datasets and our own dataset showed a high HIF-1 score was associated with high immunosuppressive TME, evidenced by fewer infiltrated CD8+ T cells, B cells, and type 1 T-helper cells and reduced cytolytic activity of CD8+ T cells. In summary, we established a specific HIF-1 score system to discriminate PDAC with various hypoxia statuses and immune microenvironments. For highly hypoxic and immunosuppressive tumors, a combination treatment strategy should be considered in the future.
    Keywords:  HIF-1; ICB; PDAC; hypoxia; immune infiltration; immunosuppression
    DOI:  https://doi.org/10.3389/fimmu.2021.790661
  12. Gut Liver. 2021 Dec 21.
       Background/Aims: CD40 agonists are thought to generate antitumor effects on pancreatic cancer via macrophages and T cells. We aimed to investigate the role of CD40 agonists in the differentiation of macrophages and treatment of human pancreatic adenocarcinoma.
    Methods: Immunohistochemistry was performed on paraffin-embedded surgical blocks from patients with pancreatic cancers to evaluate macrophage phenotypes and their relationship with survival. The effects of CD40 agonists on macrophage phenotypes and human pancreatic cancer were evaluated utilizing cell cocultures and organotypic slice cultures.
    Results: CD163+ (predominant in M2 macrophages) and FOXP3+ (predominant in regulatory T cells) expression levels in the tumors were significantly lower in patients with stage IB pancreatic cancer than in those with stage II or III disease (p=0.002 and p=0.003, respectively). Patients with high CD163+ expression had shorter overall survival than those with low CD163+ expression (p=0.002). In vitro treatment of THP-1 macrophages with a CD40 agonist led to an increase in HLA-DR+ (predominant in M1 macrophages) and a decrease in CD163+ expression in THP-1 cells. Cell cocultures showed that CD40 agonists facilitate the suppression of PANC-1 human pancreatic cancer cells by THP-1 macrophages. Organotypic slice cultures showed that CD40 agonists alter the pancreatic cancer microenvironment by shifting the macrophage phenotype toward M1 (increase HLA-DR+ and decrease CD163+ expression), decreasing the abundance of regulatory T cells, and increasing tumor cell apoptosis.
    Conclusions: CD163 is related to advanced human pancreatic cancer stages and shorter overall survival. CD40 agonists alter macrophage phenotype polarization to favor the M1 phenotype and suppress human pancreatic cancer.
    Keywords:  CD163 antigen; CD40 immunoglobulin; Macrophages; Pancreatic neoplasm; Tumor microenvironment
    DOI:  https://doi.org/10.5009/gnl210311
  13. Elife. 2021 Dec 24. pii: e62645. [Epub ahead of print]10
      Rewired metabolism is a hallmark of pancreatic ductal adenocarcinomas (PDA). Previously, we demonstrated that PDA cells enhance glycosylation precursor biogenesis through the hexosamine biosynthetic pathway (HBP) via activation of the rate limiting enzyme, glutamine-fructose 6-phosphate amidotransferase 1 (GFAT1). Here, we genetically ablated GFAT1 in human PDA cell lines, which completely blocked proliferation in vitro and led to cell death. In contrast, GFAT1 knockout did not preclude the growth of human tumor xenografts in mice, suggesting that cancer cells can maintain fidelity of glycosylation precursor pools by scavenging nutrients from the tumor microenvironment. We found that hyaluronic acid (HA), an abundant carbohydrate polymer in pancreatic tumors composed of repeating N-acetyl-glucosamine (GlcNAc) and glucuronic acid sugars, can bypass GFAT1 to refuel the HBP via the GlcNAc salvage pathway. Together, these data show HA can serve as a nutrient fueling PDA metabolism beyond its previously appreciated structural and signaling roles.
    Keywords:  cancer biology; human; mouse
    DOI:  https://doi.org/10.7554/eLife.62645
  14. Front Cell Dev Biol. 2021 ;9 795251
      Infidelity to cell fate occurs when differentiated cells lose their original identity and either revert to a more multipotent state or transdifferentiate into a different cell type, either within the same embryonic lineage or in an entirely different one. Whilst in certain circumstances, such as in wound repair, this process is beneficial, it can be hijacked by cancer cells to drive disease initiation and progression. Cell phenotype switching has been shown to also serve as a mechanism of drug resistance in some epithelial cancers. In pancreatic ductal adenocarcinoma (PDAC), the role of lineage infidelity and phenotype switching is still unclear. Two consensus molecular subtypes of PDAC have been proposed that mainly reflect the existence of cell lineages with different degrees of fidelity to pancreatic endodermal precursors. Indeed, the classical subtype of PDAC is characterised by the expression of endodermal lineage specifying transcription factors, while the more aggressive basal-like/squamous subtype is defined by epigenetic downregulation of endodermal genes and alterations in chromatin modifiers. Here, we summarise the current knowledge of mechanisms (genetic and epigenetic) of cell fate switching in PDAC and discuss how pancreatic organoids might help increase our understanding of both cell-intrinsic and cell-extrinsic factors governing lineage infidelity during the distinct phases of PDAC evolution.
    Keywords:  PDAC; cell lineage; organoid culture; pancreatic ductal adenocarcinoma; progression; therapy resistance
    DOI:  https://doi.org/10.3389/fcell.2021.795251