Building pancreatic organoids to aid drug development

Organoid Technology: A Reliable Developmental Biology Tool for Organ-Specific Nanotoxicity Evaluation

Engineered nanomaterials are bestowed with certain inherent physicochemical properties unlike their parent materials, rendering them suitable for the multifaceted needs of state-of-the-art biomedical, and pharmaceutical applications. The log-phase development of nano-science along with improved "bench to beside" conversion carries an enhanced probability of human exposure with numerous nanoparticles. Thus, toxicity assessment of these novel nanoscale materials holds a key to ensuring the safety aspects or else the global biome will certainly face a debacle. The toxicity may span from health hazards due to direct exposure to indirect means through food chain contamination or environmental pollution, even causing genotoxicity. Multiple ways of nanotoxicity evaluation include several in vitro and in vivo methods, with in vitro methods occupying the bulk of the "experimental space." The underlying reason may be multiple, but ethical constraints in in vivo animal experiments are a significant one. Two-dimensional (2D) monoculture is undoubtedly the most exploited in vitro method providing advantages in terms of cost-effectiveness, high throughput, and reproducibility. However, it often fails to mimic a tissue or organ which possesses a defined three-dimensional structure (3D) along with intercellular communication machinery. Instead, microtissues such as spheroids or organoids having a precise 3D architecture and proximate in vivo tissue-like behavior can provide a more realistic evaluation than 2D monocultures. Recent developments in microfluidics and bioreactor-based organoid synthesis have eased the difficulties to prosper nano-toxicological analysis in organoid models surpassing the obstacle of ethical issues. The present review will enlighten applications of organoids in nanotoxicological evaluation, their advantages, and prospects toward securing commonplace nano-interventions.

3D organoids derived from the small intestine: An emerging tool for drug transport research

Small intestine in vitro models play a crucial role in drug transport research. Although conventional 2D cell culture models, such as Caco-2 monolayer, possess many advantages, they should be interpreted with caution because they have relatively poor physiologically reproducible phenotypes and functions. With the development of 3D culture technology, pluripotent stem cells (PSCs) and adult somatic stem cells (ASCs) show remarkable self-organization characteristics, which leads to the development of intestinal organoids. Based on previous studies, this paper reviews the application of intestinal 3D organoids in drug transport mediated by P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multidrug resistance protein 2 (MRP2). The advantages and limitations of this model are also discussed. Although there are still many challenges, intestinal 3D organoid model has the potential to be an excellent tool for drug transport research.

Tissues and Tumor Microenvironment (TME) in 3D: Models to Shed Light on Immunosuppression in Cancer

Immunosuppression in cancer has emerged as a major hurdle to immunotherapy efforts. Immunosuppression can arise from oncogene-induced signaling within the tumor as well as from tumor-associated immune cells. Understanding various mechanisms by which the tumor can undermine and evade therapy is critical in improving current cancer immunotherapies. While mouse models have allowed for the characterization of key immune cell types and their role in tumor development, extrapolating these mechanisms to patients has been challenging. There is need for better models to unravel the effects of genetic alterations inherent in tumor cells and immune cells isolated from tumors on tumor growth and to investigate the feasibility of immunotherapy. Three-dimensional (3D) organoid model systems have developed rapidly over the past few years and allow for incorporation of components of the tumor microenvironment such as immune cells and the stroma. This bears great promise for derivation of patient-specific models in a dish for understanding and determining the impact on personalized immunotherapy. In this review, we will highlight the significance of current experimental models employed in the study of tumor immunosuppression and evaluate current tumor organoid-immune cell co-culture systems and their potential impact in shedding light on cancer immunosuppression.

DNA damage repair as a target in pancreatic cancer: state-of-the-art and future perspectives

Complex rearrangement patterns and mitotic errors are hallmarks of most pancreatic ductal adenocarcinomas (PDAC), a disease with dismal prognosis despite some therapeutic advances in recent years. DNA double-strand breaks (DSB) bear the greatest risk of provoking genomic instability, and DNA damage repair (DDR) pathways are crucial in preserving genomic integrity following a plethora of damage types. Two major repair pathways dominate DSB repair for safeguarding the genome integrity: non-homologous end joining and homologous recombination (HR). Defective HR, but also alterations in other DDR pathways, such as BRCA1, BRCA2, ATM and PALB2, occur frequently in both inherited and sporadic PDAC. Personalised treatment of pancreatic cancer is still in its infancy and predictive biomarkers are lacking. DDR deficiency might render a PDAC vulnerable to a potential new therapeutic intervention that increases the DNA damage load beyond a tolerable threshold, as for example, induced by poly (ADP-ribose) polymerase inhibitors. The Pancreas Cancer Olaparib Ongoing (POLO) trial, in which olaparib as a maintenance treatment improved progression-free survival compared with placebo after platinum-based induction chemotherapy in patients with PDAC and germline BRCA1/2 mutations, raised great hopes of a substantially improved outcome for this patient subgroup. This review summarises the relationship between DDR and PDAC, the prevalence and characteristics of DNA repair mutations and options for the clinical management of patients with PDAC and DNA repair deficiency.

A fast and simple fluorometric method to detect cell death in 3D intestinal organoids

Organoids recapitulate the (patho)physiological processes in certain tissues and organs closer than classical cell lines. Therefore, organoid technology offers great potentials in drug development and testing, and personalized medicine. In particular, organoids can be used to study and predict drug-induced toxicity in certain tissues. However, until today few methods had been reported to analyze cell death in 3D-microtissues in a quantitative manner. Here, we describe a novel fluorometric method for the quantitative measurement of specific organoid cell death. Organoids are stained simultaneously with the cell impermeable nuclear dye propidium iodide and cell permeable Hoechst33342. While Hoechst allows in-well normalization to cell numbers, propidium iodide detects relative proportion of dead cells independent of hydrogel. Measurement and analysis time, as well as usability are drastically improved in comparison to other established methods. Parallel multiplexing of our method with established assays measuring mitochondrial activity further enhances its applicability in personalized medicine and drug discovery.

Generation of Pancreatic Ductal Organoids and Whole-Mount Immunostaining of Intact Organoids

Traditionally, studies of cells and tissues have been performed on isolated primary cells or immortalized cell lines by culturing them in 2D culture dishes or flasks. However, a caveat regarding 2D culture is that the cells poorly recapitulate their in vivo counterparts, mainly due to a lack of 3D cell-cell and cell-extracellular matrix interactions. In recent years, the development of in vitro organoids as 3D culture has gained substantial attention as a model to study different tissues. In adults, pancreatic ductal cells are considered as a source of stem or progenitor cells, so developing new methods to study ductal cells would be useful. Here, we provide a protocol to isolate mouse pancreatic ductal cells and a cost-effective protocol to generate 3D organoid structures from such ductal cells. Additionally, we have devised a protocol for immunostaining of intact whole organoids without sectioning. © 2018 by John Wiley & Sons, Inc.

Organoid technology in disease modelling, drug development, personalized treatment and regeneration medicine

Organoid technology bridges the gap between conventional two-dimensional cell line culture and in vivo models. The near-physiological technology can virtually recapitulates organ development and human diseases, such as infectious diseases, genetic abnormality and even cancers. In addition, organoids can more accurately predict drug responses, and serve as an excellent platform for drug development, including efficacy evaluation, toxicity testing and pharmacokinetics analysis. Furthermore, organoids can also be exploited to explore the possible optimized treatment strategies for each individual patient. Besides, organoid technology is a promising strategy for regeneration medicine and transplantation use, which can overcome the deficiency in the supply of healthy donor tissues and inherent immunological rejection through establishing isogenic organoids from minuscule amounts of patient biopsies. Collectively, organoids hold enormous potential for clinical applications and bring basic research closer to clinical practice. In this review, we described common organoid lines, summarized the potential clinical applications, and outlined the current limitations.

Importance of organoids for personalized medicine

The establishment of organoid culture systems represents a milestone on the route toward successful personalized medicine. This mini review provides an update on the current status of organoid technology and summarizes their applications in personalized medicine. Organoids can be defined as 3D structures derived either from pluripotent or organ restricted stem cells harboring the ability to mimic in vivo architecture and multi lineage differentiation of terminally differentiated tissues. Due to their unique ability of virtually unlimited self-renewal, organoid cultures should be distinguished from previous 'sphere'-culture assays, for example, 'tumor spheres' that have already been described and applied over the last decades.

Disease Modeling in Stem Cell-Derived 3D Organoid Systems

Organoids are 3D in vitro culture systems derived from self-organizing stem cells. They can recapitulate the in vivo architecture, functionality, and genetic signature of original tissues. Thus, organoid technology has been rapidly applied to understanding stem cell biology, organogenesis, and various human pathologies. The recent development of human patient-derived organoids has enabled disease modeling with precision, highlighting their great potential in biomedical applications, translational medicine, and personalized therapy. In light of recent breakthroughs using organoids, it is only apt that we appreciate the advantages and shortcomings of this technology to exploit its full potential. We discuss recent advances in the application of organoids in studying cancer and hereditary diseases, as well as in the examination of host cell-microorganism interactions.