High-dose chemotherapeutics of intravesical chemotherapy rapidly induce mitochondrial dysfunction in bladder cancer-derived spheroids

Investigating the Radiobiological Response to Peptide Receptor Radionuclide Therapy Using Patient-Derived Meningioma Spheroids

Peptide receptor radionuclide therapy (PRRT) using 177Lu-DOTA-TATE has recently been evaluated for the treatment of meningioma patients. However, current knowledge of the underlying radiation biology is limited, in part due to the lack of appropriate in vitro models. Here, we demonstrate proof-of-concept of a meningioma patient-derived 3D culture model to assess the short-term response to radiation therapies such as PRRT and external beam radiotherapy (EBRT). We established short-term cultures (1 week) for 16 meningiomas with high efficiency and yield. In general, meningioma spheroids retained characteristics of the parental tumor during the initial days of culturing. For a subset of tumors, clear changes towards a more aggressive phenotype were visible over time, indicating that the culture method induced dedifferentiation of meningioma cells. To assess PRRT efficacy, we demonstrated specific uptake of 177Lu-DOTA-TATE via somatostatin receptor subtype 2 (SSTR2), which was highly overexpressed in the majority of tumor samples. PRRT induced DNA damage which was detectable for an extended timeframe as compared to EBRT. Interestingly, levels of DNA damage in spheroids after PRRT correlated with SSTR2-expression levels of parental tumors. Our patient-derived meningioma culture model can be used to assess the short-term response to PRRT and EBRT in radiobiological studies. Further improvement of this model should pave the way towards the development of a relevant culture model for assessment of the long-term response to radiation and, potentially, individual patient responses to PRRT and EBRT.

Emerging organoid-immune co-culture models for cancer research: from oncoimmunology to personalized immunotherapies

In the past decade, treatments targeting the immune system have revolutionized the cancer treatment field. Therapies such as immune checkpoint inhibitors have been approved as first-line treatment in a variety of solid tumors such as melanoma and non-small cell lung cancer while other therapies, for instance, chimeric antigen receptor (CAR) lymphocyte transfer therapies, are still in development. Although promising results are obtained in a small subset of patients, overall clinical efficacy of most immunotherapeutics is limited due to intertumoral heterogeneity and therapy resistance. Therefore, prediction of patient-specific responses would be of great value for efficient use of costly immunotherapeutic drugs as well as better outcomes. Because many immunotherapeutics operate by enhancing the interaction and/or recognition of malignant target cells by T cells, in vitro cultures using the combination of these cells derived from the same patient hold great promise to predict drug efficacy in a personalized fashion. The use of two-dimensional cancer cell lines for such cultures is unreliable due to altered phenotypical behavior of cells when compared with the in vivo situation. Three-dimensional tumor-derived organoids, better mimic in vivo tissue and are deemed a more realistic approach to study the complex tumor-immune interactions. In this review, we present an overview of the development of patient-specific tumor organoid-immune co-culture models to study the tumor-specific immune interactions and their possible therapeutic infringement. We also discuss applications of these models which advance personalized therapy efficacy and understanding the tumor microenvironment such as: (1) Screening for efficacy of immune checkpoint inhibition and CAR therapy screening in a personalized manner. (2) Generation of tumor reactive lymphocytes for adoptive cell transfer therapies. (3) Studying tumor-immune interactions to detect cell-specific roles in tumor progression and remission. Overall, these onco-immune co-cultures might hold a promising future toward developing patient-specific therapeutic approaches as well as increase our understanding of tumor-immune interactions.

Ex vivo chemosensitivity assay using primary ovarian cancer organoids for predicting clinical response and screening effective drugs

Selecting the best treatment for individual patients with cancer has attracted attention for improving clinical outcomes. Recent progress in organoid culture may lead to the development of personalized medicine. Unlike molecular-targeting drugs, there are no predictive methods for patient response to standard chemotherapies for ovarian cancer. We prepared organoids using the cancer tissue-originated spheroid (CTOS) method from 61 patients with ovarian cancer with 100% success rate. Chemosensitivity assays for paclitaxel and carboplatin were performed with 84% success rate using the primary organoids from 50 patients who received the chemotherapy. A wide range of sensitivities was observed among organoids for both drugs. All four clinically resistant organoids were resistant to both drugs in 18 cases in which clinical response information was available. Five out of 18 cases (28%) were double-resistant, the response rate of which was compatible with the clinical remission rate. Carboplatin was significantly more sensitive in serous than in clear cell subtypes (P = 0.025). We generated two lines of organoids, screened 1135 drugs, and found several drugs with better combinatory effects with carboplatin than with paclitaxel. Some drugs, including afatinib, have shown an additive effect with carboplatin. The organoid sensitivity assay did not predict the clinical outcomes, both progression free and overall survival.

Optimisation of Conditions for the Formation of Spheroids of Head and Neck Squamous Cell Carcinoma Cell Lines for Use as Animal Alternatives

The use of in vitro 3-D cell culture models in cancer research has yielded substantial gains in knowledge on various aspects of tumour biology. Such cell culture models could be useful in the study of head and neck squamous cell carcinoma (HNSCC), where mimicking intratumoral and intertumoral heterogeneity is especially challenging. Our research aims to establish 3-D spheroid models for HNSCC that reproduce in vitro the connections between tumour cells and the surrounding microenvironment. The aims of this study were to determine the optimal conditions for the culture and use of spheroids from HNSCC cell lines and optimal timepoint for using the spheroids obtained, to evaluate the effects of coculture with tumour-specific fibroblasts on spheroid formation, and to investigate spheroid responses to cisplatin treatment. Four HNSCC cell lines (UMSCC-11A, UMSCC-11B, UMSCC-22B and UD-SCC-01) were seeded in flat or round bottom well ultra-low attachment spheroid plates, and spheroid formation was evaluated. The HNSCC cell lines were then cocultured with stromal cells of the tumour microenvironment, producing an accelerated formation of dense spheroids. The viability of cells within the spheroids was assessed during cell culture by using a fluorescent dye. Our results suggest that: three out of the four cell lines tested could form usable spheroids with acceptable viability; the addition of stromal cells did not improve the number of viable cells; and the use of round bottom well plates supported the formation of a single spheroid, whereas flat bottom well plates led to the formation of multiple spheroids of different sizes.

Urological cancer organoids, patients' avatars for precision medicine: past, present and future

Urological cancers are common malignant cancers worldwide, with annually increasing morbidity and mortality rates. For decades, two-dimensional cell cultures and animal models have been widely used to study the development and underlying molecular mechanisms of urological cancers. However, they either fail to reflect cancer heterogeneity or are time-consuming and labour-intensive. The recent emergence of a three-dimensional culture model called organoid has the potential to overcome the shortcomings of traditional models. For example, organoids can recapitulate the histopathological and molecular diversity of original cancer and reflect the interaction between cancer and surrounding cells or stroma by simulating tumour microenvironments. Emerging evidence suggests that urine-derived organoids can be generated, which could be a novel non-invasive liquid biopsy method that provides new ideas for clinical precision therapy. However, the current research on organoids has encountered some bottlenecks, such as the lack of a standard culture process, the need to optimize the culture medium and the inability to completely simulate the immune system in vivo. Nonetheless, cell co-culture and organoid-on-a-chip have significant potential to solve these problems. In this review, the latest applications of organoids in drug screening, cancer origin investigation and combined single-cell sequencing are illustrated. Furthermore, the development and application of organoids in urological cancers and their challenges are summarised.

[Organoids as a milestone on the way to personalized treatment of urothelial carcinoma: a systematic review]

BACKGROUND

The treatment options for locally advanced and metastatic urothelial carcinoma (UC) are currently limited to established chemotherapy and immunotherapy protocols. Targeted treatment is so far restricted to a small subgroup of patients. Urothelial organoid systems could make a decisive contribution in establishing effective personalized treatment options by enabling drug response prediction through testing the sensitivity of individual patients. The aim of this article is to describe the state of the science of clinically applicable organoid systems for UC.

METHODOLOGY

A systematic literature search was conducted in several medical databases (Medline, Cochrane Library) and study registers (ClinicalTrials.gov, the EU Clinical Trials Register and the WHO International Clinical Trials Registry). The search terms and the search strategy were adapted to the databases used.

RESULTS

Overall, 7 studies met the inclusion criteria on the topic of UC organoids. These studies describe the fundamental workflow in establishing organoid systems in patients with tumors of the urinary bladder or the renal pelvis. The success rates in generating organoids from non-muscle-invasive bladder cancer were 70-77% and for muscle-invasive bladder cancer 42%. For patient organoids systematic drug testing was carried out.

CONCLUSION

The generation of UC organoids is feasible and the ex vivo testing of individual treatment forms is possible. Due to the lack of a standardized methodology, their implementation remains experimental at the moment. The methodology has a high potential to provide a personalized treatment concept to patients with urothelial cancer.

Patient-Derived Bladder Cancer Organoid Models in Tumor Biology and Drug Testing: A Systematic Review

Simple Summary

Primary culture of cancer cells from patient tumors in a physiologically relevant system can provide information about tumor biology, disentangle the role of different cell types within the tumors, and give information about drug sensitivity for the development of cancer-targeted therapies and precision medicine. This requires the use of well-characterized and easily expandable tumor models. This review focuses on 3D models developed from primary human tissue including normal urothelium or bladder cancer samples, the characteristics of the models, and to what extent the organoids represent the diversity observed among human tumors.

Abstract

Bladder cancer is a common and highly heterogeneous malignancy with a relatively poor outcome. Patient-derived tumor organoid cultures have emerged as a preclinical model with improved biomimicity. However, the impact of the different methods being used in the composition and dynamics of the models remains unknown. This study aims to systematically review the literature regarding patient-derived organoid models for normal and cancer tissue of the bladder, and their current and potential future applications for tumor biology studies and drug testing. A PRISMA-compliant systematic review of the PubMED, Embase, Web of Sciences, and Scopus databases was performed. The results were analyzed based on the methodologies, comparison with primary tumors, functional analysis, and chemotherapy and immunotherapy testing. The literature search identified 536 articles, 24 of which met the inclusion criteria. Bladder cancer organoid models have been increasingly used for tumor biology studies and drug screening. Despite the heterogeneity between methods, organoids and primary tissues showed high genetic and phenotypic concordance. Organoid sensitivity to chemotherapy matched the response in patient-derived xenograft (PDX) models and predicted response based on clinical and mutation data. Advances in bioengineering technology, such as microfluidic devices, bioprinters, and imaging, are likely to further standardize and expand the use of organoids.

In vitro assessment of intra-operative and post-operative environment in reducing bladder cancer recurrence

Urinary bladder cancer is a common cancer worldwide. Currently, the modality of treating and monitoring bladder cancer is wide. Nonetheless, the high recurrence rate of non-muscle-invasive bladder cancer after surgical resection is still unsatisfactory. Hereby, our study demonstrated whether the intra-operative and post-operative environments will affect bladder cancer recurrence utilizing in vitro cell line model. Bladder cancer cell lines were submerged in four different irrigating fluids for assessing their tumorigenic properties. Our results showed that sterile water performed the best in terms of the magnitude of cytotoxicity to cell lines. Besides, we also investigated cytotoxic effects of the four irrigating agents as well as mitomycin C (MMC) in normothermic and hyperthermic conditions. We observed that sterile water and MMC had an increased cytotoxic effect to bladder cancer cell lines in hyperthermic conditions. Altogether, our results could be translated into clinical practice in the future by manipulating the intra-operative and post-operative conditions in order to lower the chance of residual cancer cells reimplant onto the bladder, which in turns, reducing the recurrence rate of bladder cancers.

Patient derived models of bladder cancer enrich the signal of the tumor cell transcriptome facilitating the analysis of the tumor cell compartment

The evolving paradigm of the molecular classification of bladder cancer requires models that represent the classifications with less heterogeneity. Robust transcriptome based molecular classifications are essential to address tumor heterogeneity. Patient derived models (PDMs) are a powerful preclinical tool to study specific tumor compartments. We tested if the consensus molecular subtype analysis was applicable to PDMs and evaluated the tumor compartment each model represents. PDMs derived from surgical specimens were established as xenografts (PDX), organoids (PDO), and spheroids (PDS). The surgical specimens and PDMs were molecularly characterized by RNA sequencing. PDMs that were established in immune deficient mice or in vitro significantly downregulated transcripts related to the immune and stromal compartments compared to the surgical specimens. However, PDMs upregulate a patient-specific bladder cancer cell signal which allowed for analysis of cancer cell pathways independent of the tumor microenvironment. Based on transcriptomic signatures, PDMs are more similar to their surgical specimen than the model type; indicating that the PDMs retained unique features of the tumor from which the PDM was derived. When comparing models, PDX models were the most similar to the surgical specimen, while PDO and PDS models were most similar to each other. When the consensus molecular subtype classification system was applied to both the surgical samples and the three PDMs, good concordance was found between all samples indicating that this system of classification can be applied to PDO and PDS models. PDMs reduce tumor heterogeneity and allow analysis of tumor cells while maintaining the gene expression profile representative of the original tumor.

Urothelial cancer organoids: a tool for bladder cancer research

Background

Bladder cancer ranks among the top ten most common tumor types worldwide and represents a growing healthcare problem, accounting for a large part of total healthcare costs. Chemotherapy is effective in a subset of patients, while causing severe side effects. Tumor pathogenesis and drug resistance mechanisms are largely unknown. Precision medicine is failing in bladder cancer, as bladder tumors are genetically and molecularly very heterogeneous. Currently, therapeutic decision-making depends on assessing a single fragment of surgically acquired tumor tissue.

Objective

New preclinical model systems for bladder cancer are indispensable for developing therapeutic strategies tailored to individual patient and tumor characteristics. Organoids are small 3D tissue cultures that simulate small-size organs “in a dish” and tumoroids are a special type of cancer organoid (i.e., malignant tissue).

Materials and methods

Since 2016, we have collaborated with the renowned Hubrecht Institute to provide proof of concept of tissue-based bladder tumoroids mimicking parental tumors. We have developed a living biobank containing bladder organoids and tumoroids grown from over 50 patient samples, which reflect crucial aspects of bladder cancer pathogenesis.

Results

Histological and immunofluorescence analysis indicated that the heterogeneity and subclassification of tumoroids mimicked those of corresponding parental tumor samples. Thus, urothelial tumoroids mimic crucial aspects of bladder cancer pathogenesis.

Conclusion

Research with urothelial tumoroids will open up new avenues for bladder cancer pathogenesis and drug-resistance research as well as for precision medicine approaches.

[Organoids for the advancement of intraoperative diagnostic procedures]

In the context of cancer surgery, there is always a trade-off between oncological safety and preservation of function. This is especially true in pelvic surgery due to the close relationship to the pelvic floor muscles, blood supply and nerves. Currently, risk models, preoperative imaging, the surgeon's assessment, and the intraoperative frozen section serve as the basis for decision-making. New imaging techniques and standardization in frozen section have significantly improved this in recent years. However, limitations remain due to time delays as well as more difficult correct anatomical assignment in the follow-up. Alternative intraoperative techniques may overcome this limitation in the future. Patient-derived organoids have emerged as an important new research vehicle in recent years. They are based on tumor stem cells that, under special culture conditions, form three-dimensional replicas of the original tissue. This makes them ideally suited for testing individual system therapies but also as a validation technique for new intraoperative diagnostic procedures. The Research Training Group 2543/I, which is funded by the German Research Foundation, is researching the potential of new diagnostic methods in an interdisciplinary team regarding validation in addition to intraoperative frozen sections.

Preclinical Models for Bladder Cancer Research

At diagnosis, more than 70% of bladder cancers (BCs) are at the non-muscle-invasive bladder cancer (NMIBC) stages, which are usually treated with transurethral resection followed by intravesical instillation. For the remaining advanced cancers, systemic therapy is the standard of care, with addition of radical cystectomy in cases of locally advanced cancer. Because of the difference in treatment modalities, different models are needed to advance the care of NMIBC and advanced BC. This article gives a comprehensive review of both in vitro and in vivo BC models and compares the advantages and drawbacks of these preclinical systems in BC research.

A bladder cancer patient-derived xenograft displays aggressive growth dynamics in vivo and in organoid culture

Bladder cancer is among the most prevalent cancers worldwide. Currently, few bladder cancer models have undergone thorough characterization to assess their fidelity to patient tumors, especially upon propagation in the laboratory. Here, we establish and molecularly characterize CoCaB 1, an aggressive cisplatin-resistant muscle-invasive bladder cancer patient-derived xenograft (PDX) and companion organoid system. CoCaB 1 was a subcutaneous PDX model reliably transplanted in vivo and demonstrated an acceleration in growth upon serial transplantation, which was reflected in organoid and 2D cell culture systems. Transcriptome analysis revealed progression towards an increasingly proliferative and stem-like expression profile. Gene expression differences between organoid and PDX models reflected expected differences in cellular composition, with organoids enriched in lipid biosynthesis and metabolism genes and deprived of extracellular components observed in PDXs. Both PDX and organoid models maintained the histological fidelity and mutational heterogeneity of their parental tumor. This study establishes the CoCaB 1 PDX and organoid system as companion representative tumor models for the development of novel bladder cancer therapies.

[The tumor stem cell niche of head and neck - point of intersection with therapeutic potential?]

An increasing amount of evidence suggests the existence of a stem cell-like population in head and neck squamous cell carcinoma (HNSCC). These cells have been termed cancer stem cells (CSC) due to the shared properties with somatic stem cells, such as the ability to self-renew and differentiate. Furthermore, the CSC are thought to be resistant to antineoplastic treatments and are therefore clinically relevant. As with somatic stem cells, CSC are thought to reside in a specialized supportive microenvironment, called the stem cell niche. One possible strategy to target the CSC could be through affecting functions of the stem cell niche.Stromal cell-derived factor-1 (SDF-1) is a multifunctional cytokine, which is secreted by e. g. stromal cells within the niche. SDF-1 is known to be the major regulator of stem cell trafficking between the niche and the peripheral vascular system. It elicits the chemotactic activity through interaction with a transmembrane receptor CXCR4, expressed by CSC. The SDF-1-CXCR4-axis is thought to play a crucial role in the interaction between CSC and their supportive cells in the tumor niche. A better understanding of these interactions could help in gaining further insight into the pathophysiology of progression/recurrence of malignant diseases and aid in finding new strategies for therapy.Specialized cell culture models are of advantage for deciphering the mechanisms of interaction between CSC and their niche. We anticipate that the recent technological advancements in bioprinting and the development of complex 3D cell culture model systems will contribute to our understanding of these mechanisms and to the establishment of individualized therapies.Here were provide an overview of the current knowledge on the CSC-tumor stem cell niche interactions in HNSCC with a focus on the SDF-1-CXCR4 axis.

Novel ex vivo disease model for extramammary Paget's disease using the cancer tissue-originated spheroid method

BACKGROUND

Extramammary Paget's disease (EMPD) is a rare skin cancer that frequently occurs in the anogenital region in the elderly. Prognosis in patients with metastatic EMPD is poor as EMPD treatment has advanced little in recent years, primarily because no EMPD cell line has been established.

OBJECTIVE

We aimed to establish an ex vivo EMPD disease model using the cancer tissue-originated spheroid (CTOS) method, which is used to prepare and culture primary cancer cells while maintaining cell-cell contact.

METHODS

Thirteen samples from 12 EMPD patients were obtained. CTOSs were prepared and cultured using CTOS method. Histopathological examination of the CTOSs was performed. We investigated optimum medium conditions and effects of growth factors for CTOS growth. Chemo-sensitivity assays were conducted.

RESULTS

CTOSs were successfully prepared from 3 primary lesions and 2 metastatic lymph nodes. Of these, 2 CTOSs (EMPD-3 and EMPD-4) could be maintained and passaged long term ex vivo. Following transplantation of CTOSs to NOD/Scid mice, CTOS-derived xenotumors exhibited ductal formation, indicating that CTOSs retained the original tumor characteristics. Chemo-sensitivity assays revealed that docetaxel significantly inhibited EMPD-3 growth in a dose-dependent manner, whereas EMPD-4 was not clearly inhibited. These findings indicate the heterogeneity of EMPD and potential use of chemosensitivity assays with patient-derived CTOS to select the most effective drugs for each patient.

CONCLUSION

To our knowledge, this study represents the first establishment of an ex vivo-EMPD disease model involving conventional cell lines. EMPD CTOSs might be useful for developing new therapeutic strategies.

Organoid model of urothelial cancer: establishment and applications for bladder cancer research

3D cancer cell models are suitable for drug evaluation because they more precisely mimic tissue architecture than 2D cultures. To study cytotoxicity of anticancer agents, the most sensitive CellTiter-Glo 3D assay is used. However, this is an end point assay, so it is not possible to consider the variance of the starting material amount in the final reading. It is difficult to maintain an even plating density of 3D organoids for cytotoxicity analysis. We present a simple, 3D bladder cancer culture that can be maintained, cryopreserved and used for molecular and drug response studies. We applied a simple modification of the drug response assay for 3D cultures by measuring the background signal with the CellTiter Blue assay before drug application.

Using Machine Learning Methods and Structural Alerts for Prediction of Mitochondrial Toxicity

Over the last few years more and more organ and idiosyncratic toxicities were linked to mitochondrial toxicity. Despite well-established assays, such as the seahorse and Glucose/Galactose assay, an in silico approach to mitochondrial toxicity is still feasible, particularly when it comes to the assessment of large compound libraries. Therefore, in silico approaches could be very beneficial to indicate hazards early in the drug development pipeline. By combining multiple endpoints, we derived the largest so far published dataset on mitochondrial toxicity. A thorough data analysis shows that molecules causing mitochondrial toxicity can be distinguished by physicochemical properties. Finally, the combination of machine learning and structural alerts highlights the suitability for in silico risk assessment of mitochondrial toxicity.

Application of Cancer Organoid Model for Drug Screening and Personalized Therapy

Drug screening—i.e., testing the effects of a number of drugs in multiple cell lines—is used for drug discovery and development, and can also be performed to evaluate the heterogeneity of a disease entity. Notably, intertumoral heterogeneity is a large hurdle to overcome for establishing standard cancer treatment, necessitating disease models better than conventional established 2D cell lines for screening novel treatment candidates. In the present review, we outline recent progress regarding experimental cancer models having more physiological and clinical relevance for drug screening, which are important for the successful evaluation of cellular response to drugs. The review is particularly focused on drug screening using the cancer organoid model, which is emerging as a better physiological disease model than conventional established 2D cell lines. We also review the use of cancer organoids to examine intertumor and intratumor heterogeneity, and introduce the perspective of the clinical use of cancer organoids to enable precision medicine.

Mouse and human urothelial cancer organoids: A tool for bladder cancer research

Bladder cancer is a common malignancy that has a relatively poor outcome. Lack of culture models for the bladder epithelium (urothelium) hampers the development of new therapeutics. Here we present a long-term culture system of the normal mouse urothelium and an efficient culture system of human bladder cancer cells. These so-called bladder (cancer) organoids consist of 3D structures of epithelial cells that recapitulate many aspects of the urothelium. Mouse bladder organoids can be cultured efficiently and genetically manipulated with ease, which was exemplified by creating genetic knockouts in the tumor suppressors Trp53 and Stag2. Human bladder cancer organoids can be derived efficiently from both resected tumors and biopsies and cultured and passaged for prolonged periods. We used this feature of human bladder organoids to create a living biobank consisting of bladder cancer organoids derived from 53 patients. Resulting organoids were characterized histologically and functionally. Organoid lines contained both basal and luminal bladder cancer subtypes based on immunohistochemistry and gene expression analysis. Common bladder cancer mutations like TP53 and FGFR3 were found in organoids in the biobank. Finally, we performed limited drug testing on organoids in the bladder cancer biobank.

High-throughput screening in colorectal cancer tissue-originated spheroids

Patient‐derived cancer organoid culture is an important live material that reflects clinical heterogeneity. However, the limited amount of organoids available for each case as well as the considerable amount of time and cost to expand in vitro makes it impractical to perform high‐throughput drug screening using organoid cultures from multiple patients. Here, we report an advanced system for the high‐throughput screening of 2427 drugs using the cancer tissue‐originated spheroid (CTOS) method. In this system, we apply the CTOS method in an ex vivo platform from xenograft tumors, using machines to handle CTOS and reagents, and testing a CTOS reference panel of multiple CTOS lines for the hit drugs. CTOS passages in xenograft tumors resulted in minimal changes of morphological and genomic status, and xenograft tumor generation efficiently expanded the number of CTOS to evaluate multiple drugs. Our panel of colorectal cancer CTOS lines exhibited diverse sensitivities to the hit compounds, demonstrating the usefulness of this system for investigating highly heterogeneous disease.

Head and neck cancer organoids established by modification of the CTOS method can be used to predict in vivo drug sensitivity

OBJECTIVES

Currently there are no standard biomarkers of head and neck squamous cell carcinoma (HNSCC) response to therapy. This is, due to a lack of adequate predictive tumor models. To this end, we established cancer organoid lines from individual patient's tumors, and characterized their growth characteristics and response to different drug treatments with the objective of using these models for prediction of treatment response.

MATERIALS AND METHODS

Forty-three patients' samples were processed to establish organoids. To analyze the character of these organoids, immunohistochemistry, Western blotting, drug sensitivity assays, clonogenic survival assays, and animal experiments were performed. The HPV status and TP53 mutational status were also confirmed in these lines.

RESULTS

HNSCC organoids were successfully established with success rate of 30.2%. Corresponding two-dimensional cell lines were established from HNSCC organoids at higher success rate (53.8%). These organoids showed similar histological features and stem cell, epithelial and mesenchymal marker expression to the original tumors, thus recapitulating many of the characteristics of the original tumor cells. The cisplatin and docetaxel IC50 were determined for HNSCC organoids and the corresponding 2D cell lines using drug sensitivity and clonogenic survival assays. Responses to drug treatment in vivo were found to be similar to the IC₅₀ calculated from organoids by drug sensitivity assays in vitro.

CONCLUSION

We established novel in vitro HNSCC cancer organoid lines retaining many properties of the original tumors from they were derived. These organoids can predict in vivo drug sensitivity and may represent useful tools to develop precision treatments for HNSCC.

Bufalin induced apoptosis of bladder carcinoma cells through the inactivation of Na+K+-ATPase

Bufalin has been demonstrated to possess a wide range of pharmacological effects. Among these is its antitumour effect, which has been confirmed in multiple organs or tissues and provoked many concerns. However, its cytostatic effect and underlying mechanism in bladder cancer has not thoroughly been elucidated. This study aimed to investigate the hypothesis that Bufalin induces cell apoptosis and inhibits cell growth in bladder cancer through the inactivation of Na+/K+-ATPase (NKA). In the current study, it was demonstrated that Bufalin remarkably inhibited cell viability and induced cell apoptosis in bladder cancer cell line T24. Subsequently, we found that the expression of NKA was significantly supressed in Bufalin-treated cells and the NKA-α3 isoform was most sensitive to Bufalin among all α subunits of NKA. By transfection with NKA-α3 overexpressing plasmids, the expression of the NKA-α3 subunit was upregulated and NKA-α3 overexpression was found to markedly attenuated Bufalin-induced cell apoptosis in T24 cells, suggesting NKA-α3 played a critical role in Bufalin-induced cell apoptosis. Taken together, the present study confirmed that Bufalin promotes tumour apoptosis and inhibits tumour growth in bladder cancer in vitro, and this antitumour effect may be ascribed to the inactivation of NKA.

Three-dimensional organoid culture reveals involvement of Wnt/β-catenin pathway in proliferation of bladder cancer cells

There has been increasing awareness of the importance of three-dimensional culture of cancer cells. Tumor cells growing as multicellular spheroids in three-dimensional culture, alternatively called organoids, are widely believed to more closely mimic solid tumors in situ. Previous studies concluded that the Wnt/β-catenin pathway is required for regeneration of the normal urothelium after injury and that β-catenin is upregulated in human bladder cancers, but no clear evidence has been advanced to support the idea that the Wnt/β-catenin pathway is directly involved in deregulated proliferation and the other malignant characteristics of bladder cancer cells. Here we report that the Wnt/β-catenin pathway activator, CHIR99021, promoted proliferation of established human bladder cancer cell lines when they were grown in organoid culture but not when they were grown in conventional adherent cultures. CHIR99021 activated Wnt/β-catenin pathway in bladder cancer cell lines in organoid culture. CHIR99021 also stimulated proliferation and the Wnt/b-catenin pathway in primary human bladder cancer organoids. RNAi-mediated knockdown of β-catenin blocked growth of organoids. The effects of CHIR99021 were associated with decreased expression of the urothelial terminal differentiation marker, cytokeratin 20. Our data suggest that the Wnt/β-catenin pathway is required for the proliferation of bladder cancer cells in three-dimensional organoid culture and provide a concrete example of why organoid culture is important for cancer research.

Spheroid Cultures of Primary Urothelial Cancer Cells: Cancer Tissue-Originated Spheroid (CTOS) Method

Increasingly, it has been recognized that studying cancer samples from individual patients is important for the development of effective therapeutic strategies and in endeavors to overcome therapy resistance. Primary cultures of cancer cells acutely dissected from individual patients can provide a platform that enables the study and characterization of individual tumors. To that end, we have developed a method for preparing cancer cells in the form of multi-cellular spheroids. The cells can be derived from patient tumors (primary cells), from patient-derived xenografts, or from genetically- or chemically induced animal tumors. This method of culturing spheroids composed of cells derived from cancer tissues can be applied to various types of cancer, including urothelial cancer. The method is based on the principle of retaining cell-cell contact throughout cancer cell preparation and culturing. The first step is a partial digestion of the tumor specimen into small fragments; these fragments spontaneously form spheroidal shapes within several hours. The spheroid is referred to as a cancer tissue-originated spheroid (CTOS). The advantage of the CTOS method is that it allows one to prepare pure cancer cells at high yield. CTOSs can be stably cultured in serum-free conditions. The CTOS method can be applied to drug sensitivity assays, drug screening, and analyses of intracellular signaling. Moreover, the CTOS method provides a platform for studying the nature of cancer cell clusters.

Ex vivo culture of tumor cells from N-methyl-N-nitrosourea-induced bladder cancer in rats: Development of organoids and an immortalized cell line

OBJECTIVE

We ex vivo cultured primary tumor cells from N-methyl-N-nitrosourea (MNU)-induced bladder tumors in rats and established an immortalized cell line from them.

MATERIALS AND METHODS

Bladder tumors in rats were induced by instillation of MNU into the murine bladder. Primary tumor cells were prepared by the cancer-tissue originated spheroid method. An immortalized cell line was established by co-culture with fibroblasts. The cultured tumor cells were molecularly and functionally characterized by quantitative real-time polymerase chain reaction, Western blot, growth assay, and transwell migration assay.

RESULTS

Primary tumor cells were successfully prepared as multicellular spheroids from MNU-induced bladder tumors. The differentiation marker expression patterns observed in the original tumors were largely retained in the spheroids. We succeeded in establishing a cell line from the spheroids and named it T-MNU-1. Although basal markers (CK14 and CK5) were enriched in T-MNU-1 compared to the spheroids, T-MNU-1 expressed both luminal and basal markers. T-MNU-1 was able to migrate through a transwell.

CONCLUSIONS

Tumor cells in MNU-induced bladder tumors were successfully cultured ex vivo as organoids, and an immortalized cell line was also established from them. The ex vivo models offer a platform that enables analysis of intrinsic characteristics of tumor cells excluding influence of microenvironment in MNU-induced bladder tumors.

High-Content Monitoring of Drug Effects in a 3D Spheroid Model

A recent decline in the discovery of novel medications challenges the widespread use of 2D monolayer cell assays in the drug discovery process. As a result, the need for more appropriate cellular models of human physiology and disease has renewed the interest in spheroid 3D culture as a pertinent model for drug screening. However, despite technological progress that has significantly simplified spheroid production and analysis, the seeming complexity of the 3D approach has delayed its adoption in many laboratories. The present report demonstrates that the use of a spheroid model may be straightforward and can provide information that is not directly available with a standard 2D approach. We describe a cost-efficient method that allows for the production of an array of uniform spheroids, their staining with vital dyes, real-time monitoring of drug effects, and an ATP-endpoint assay, all in the same 96-well U-bottom plate. To demonstrate the method performance, we analyzed the effect of the preclinical anticancer drug MLN4924 on spheroids formed by VCaP and LNCaP prostate cancer cells. The drug has different outcomes in these cell lines, varying from cell cycle arrest and protective dormancy to senescence and apoptosis. We demonstrate that by using high-content analysis of spheroid arrays, the effect of the drug can be described as a series of EC50 values that clearly dissect the cytostatic and cytotoxic drug actions. The method was further evaluated using four standard cancer chemotherapeutics with different mechanisms of action, and the effect of each drug is described as a unique multi-EC50 diagram. Once fully validated in a wider range of conditions, this method could be particularly valuable for phenotype-based drug discovery.

Chemomechanically engineered 3D organotypic platforms of bladder cancer dormancy and reactivation

Tumors undergo periods of dormancy followed by reactivation leading to metastatic disease. Arrest in the G0/G1 phase of the cell cycle and resistance to chemotherapeutic drugs are key hallmarks of dormant tumor cells. Here, we describe a 3D platform of bladder cancer cell dormancy and reactivation facilitated by a novel aminoglycoside-derived hydrogel, Amikagel. These 3D dormant tumor microenvironments (3D-DTMs) were arrested in the G0/G1 phase and were highly resistant to anti-proliferative drugs. Inhibition of targets in the cellular protein production machinery led to induction of endoplasmic reticulum (ER) stress and complete ablation of 3D-DTMs. Nanoparticle-mediated calcium delivery significantly accelerated ER stress-mediated 3D-DTM death. Transfer of 3D-DTMs onto weaker and adhesive Amikagels resulted in selective reactivation of a sub-population of N-cadherin deficient cells from dormancy. Whole-transcriptome analyses further indicated key biochemical differences between dormant and proliferative cancer cells. Taken together, our results indicate that 3D bladder cancer microenvironments of dormancy and reactivation can facilitate fundamental advances and novel drug discovery in cancer.

Oxymatrine inhibits proliferation of human bladder cancer T24 cells by inducing apoptosis and cell cycle arrest

Oxymatrine has been shown to exert an antitumor effect on several types of cancer cells. However, the role of oxymatrine in bladder cancer has not yet been evaluated. The present study was designed to investigate the potential anti-proliferative effect of oxymatrine on bladder cancer T24 cells and the possible mechanisms involved. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine cell growth, and the cell morphology was examined using hematoxylin and eosin staining, wrights' staining and electron microscopy. The caspase-3 and survivin mRNA and protein levels were assessed using reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. The expression of tumor protein p53 (p53), Bcl-2-associated X protein (Bax) and B-cell lymphoma 2 (Bcl-2) were analyzed using immunohistochemistry. Oxymatrine inhibited the proliferation of the T24 cells in a dose- and time-dependent manner. Oxymatrine also induced apoptosis and cell cycle arrest in the cells, in association with the upregulation of caspase-3 and Bax, and the downregulation of survivin, Bcl-2 and p53 expression. Overall, oxymatrine inhibits the proliferation of human bladder cancer cells by inducing apoptosis and cell cycle arrest via mechanisms that involve p53-Bax signaling and the downregulation of survivin expression.

Dynamic Change in p63 Protein Expression during Implantation of Urothelial Cancer Clusters

Although the dissemination of urothelial cancer cells is supposed to be a major cause of the multicentricity of urothelial tumors, the mechanism of implantation has not been well investigated. Here, we found that cancer cell clusters from the urine of patients with urothelial cancer retain the ability to survive, grow, and adhere. By using cell lines and primary cells collected from multiple patients, we demonstrate that △ Np63α protein in cancer cell clusters was rapidly decreased through proteasomal degradation when clusters were attached to the matrix, leading to downregulation of E-cadherin and upregulation of N-cadherin. Decreased △ Np63α protein level in urothelial cancer cell clusters was involved in the clearance of the urothelium. Our data provide the first evidence that clusters of urothelial cancer cells exhibit dynamic changes in △ Np63α expression during attachment to the matrix, and decreased △ Np63α protein plays a critical role in the interaction between cancer cell clusters and the urothelium. Thus, because △ Np63α might be involved in the process of intraluminal dissemination of urothelial cancer cells, blocking the degradation of △ Np63α could be a target of therapy to prevent the dissemination of urothelial cancer.

An integrin-targeting nanosystem as a carrier of the selenadiazole derivative to induce ROS-mediated apoptosis in bladder cancer cells, from rational design to action mechanisms

Herein an integrin-targeting nanosystem is rationally designed and used as a carrier of a selenadiazole derivative to induce ROS-mediated apoptosis in bladder cancer cells.