In vivo-like growth of human tumors in vitro

Cancer organoids 2.0: modelling the complexity of the tumour immune microenvironment

The development of neoplasia involves a complex and continuous interplay between malignantly transformed cells and the tumour microenvironment (TME). Cancer immunotherapies targeting the immune TME have been increasingly validated in clinical trials but response rates vary substantially between tumour histologies and are often transient, idiosyncratic and confounded by resistance. Faithful experimental models of the patient-specific tumour immune microenvironment, capable of recapitulating tumour biology and immunotherapy effects, would greatly improve patient selection, target identification and definition of resistance mechanisms for immuno-oncology therapeutics. In this Review, we discuss currently available and rapidly evolving 3D tumour organoid models that capture important immune features of the TME. We highlight diverse opportunities for organoid-based investigations of tumour immunity, drug development and precision medicine.

Patient-derived tumor organoids: a new avenue for preclinical research and precision medicine in oncology

Over the past decade, the emergence of patient-derived tumor organoids (PDTOs) has broadened the repertoire of preclinical models and progressively revolutionized three-dimensional cell culture in oncology. PDTO can be grown from patient tumor samples with high efficiency and faithfully recapitulates the histological and molecular characteristics of the original tumor. Therefore, PDTOs can serve as invaluable tools in oncology research, and their translation to clinical practice is exciting for the future of precision medicine in oncology. In this review, we provide an overview of methods for establishing PDTOs and their various applications in cancer research, starting with basic research and ending with the identification of new targets and preclinical validation of new anticancer compounds and precision medicine. Finally, we highlight the challenges associated with the clinical implementation of PDTO, such as its representativeness, success rate, assay speed, and lack of a tumor microenvironment. Technological developments and autologous cocultures of PDTOs and stromal cells are currently ongoing to meet these challenges and optimally exploit the full potential of these models. The use of PDTOs as standard tools in clinical oncology could lead to a new era of precision oncology in the coming decade.

Efficacy of Recombinant Methioninase on Late-stage Patient Cancer in the Histoculture Drug Response Assay (HDRA) as a Potential Functional Biomarker of Sensitivity to Methionine-restriction Therapy in the Clinic

Background/Aim

The present study utilized the three-dimensional histoculture drug response assay (HDRA) to determine the efficacy of recombinant methioninase (rMETase) on tumor tissue resected from patients with late-stage cancer, as a functional biomarker of sensitivity to methionine restriction therapy.

Patients and Methods

Resected peritoneal-metastatic cancer, including colorectal cancer, pancreatic cancer, ovarian cancer, and pseudomyxoma were placed on Gelform in RPMI 1640 medium for seven days and treated with rMETase from 2.5 U/ml to 20 U/ml. Cell viability was determined using the MTT assay. A total of 48 patients with late-stage cancer underwent testing for rMETase responsiveness using the HDRA.

Results

Colorectal cancer and pseudomyxoma had the highest sensitivity to rMETase. Pancreatic and ovarian cancer also responded to rMETase, but to a lesser degree.

Conclusion

Patients with tumors with at least 40% sensitivity to rMETase in the HDRA are being considered as candidates for methionine restriction therapy, which includes the use of rMETase in combination with a low-methionine diet.

Patient-Derived Ex Vivo Cultures and Endpoint Assays with Surrogate Biomarkers in Functional Testing for Prediction of Therapeutic Response

Prediction of therapeutic outcomes is important for cancer patients in order to reduce side effects and improve the efficacy of anti-cancer drugs. Currently, the most widely accepted method for predicting the efficacy of anti-cancer drugs is gene panel testing based on next-generation sequencing. However, gene panel testing has several limitations. For example, only 10% of cancer patients are estimated to have druggable mutations, even if whole-exome sequencing is applied. Additionally, even if optimal drugs are selected, a significant proportion of patients derive no benefit from the indicated drug treatment. Furthermore, most of the anti-cancer drugs selected by gene panel testing are molecularly targeted drugs, and the efficacies of cytotoxic drugs remain difficult to predict. Apart from gene panel testing, attempts to predict chemotherapeutic efficacy using ex vivo cultures from cancer patients have been increasing. Several groups have retrospectively demonstrated correlations between ex vivo drug sensitivity and clinical outcome. For ex vivo culture, surgically resected tumor tissue is the most abundant source. However, patients with recurrent or metastatic tumors do not usually undergo surgery, and chemotherapy may be the only option for those with inoperable tumors. Therefore, predictive methods using small amounts of cancer tissue from diagnostic materials such as endoscopic, fine-needle aspirates, needle cores and liquid biopsies are needed. To achieve this, various types of ex vivo culture and endpoint assays using effective surrogate biomarkers of drug sensitivity have recently been developed. Here, we review the variety of ex vivo cultures and endpoint assays currently available.

Making In Vitro Tumor Models Whole Again

As a reductionist approach, patient-derived in vitro tumor models are inherently still too simplistic for personalized drug testing as they do not capture many characteristics of the tumor microenvironment (TME), such as tumor architecture and stromal heterogeneity. This is especially problematic for assessing stromal-targeting drugs such as immunotherapies in which the density and distribution of immune and other stromal cells determine drug efficacy. On the other end, in vivo models are typically costly, low-throughput, and time-consuming to establish. Ex vivo patient-derived tumor explant (PDE) cultures involve the culture of resected tumor fragments that potentially retain the intact  TME of the original tumor. Although developed decades ago, PDE cultures have not been widely adopted likely because of their low-throughput and poor long-term viability. However, with growing recognition of the importance of patient-specific TME in mediating drug response, especially in the field of immune-oncology, there is an urgent need to resurrect these holistic cultures. In this Review, the key limitations of patient-derived tumor explant cultures are outlined and technologies that have been developed or could be employed to address these limitations are discussed. Engineered holistic tumor explant cultures may truly realize the concept of personalized medicine for cancer patients.

Patient-derived models: Promising tools for accelerating the clinical translation of breast cancer research findings

Breast cancer has become the highest incidence of cancer in women. It was extensively and deeply studied by biologists and medical workers worldwide. However, the meaningful results in lab researches cannot be realized in clinical, and a part of new drugs in clinical experiments do not obtain as good results as the preclinical researches. It is urgently that promote a kind of breast cancer research models that can get study results closer to the physiological condition of the human body. Patient-derived models (PDMs) originating from clinical tumor, contain primary elements of tumor and maintain key clinical features of tumor. So they are promising research models to facilitate laboratory researches translate to clinical application, and predict the treatment outcome of patients. In this review, we summarize the establishment of PDMs of breast cancer, reviewed the application of PDMs in clinical translational researches and personalized precision medicine with breast cancer as an example, to improve the understanding of PDMs among researchers and clinician, facilitate them to use PDMs on a large scale of breast cancer researches and promote the clinical translation of laboratory research and new drug development.

Les tumoroïdes, modèles précliniques en plein essor pour l’oncologie

La récente émergence des cultures d’organoïdes tumoraux, ou tumoroïdes, a permis d’enrichir le répertoire des modèles précliniques en oncologie. Très proches de la tumeur dont elles dérivent, ces microtumeurs offrent de nombreuses possibilités en termes de recherche fondamentale, telles que l’étude de la carcinogenèse ou de la chimioré-sistance, de validation préclinique de nouvelles molécules à visée anticancéreuse, ou encore de personnalisation des traitements. Divers développements techniques et l’enrichissement des tumoroïdes par l’addition d’autres types cellulaires sont actuellement en cours pour améliorer la pertinence de ces modèles et exploiter de façon optimale leur remarquable potentiel.

CAR T Cell Locomotion in Solid Tumor Microenvironment

The promising outcomes of chimeric antigen receptor (CAR) T cell therapy in hematologic malignancies potentiates its capability in the fight against many cancers. Nevertheless, this immunotherapy modality needs significant improvements for the treatment of solid tumors. Researchers have incrementally identified limitations and constantly pursued better CAR designs. However, even if CAR T cells are armed with optimal killer functions, they must overcome and survive suppressive barriers imposed by the tumor microenvironment (TME). In this review, we will discuss in detail the important role of TME in CAR T cell trafficking and how the intrinsic barriers contribute to an immunosuppressive phenotype and cancer progression. It is of critical importance that preclinical models can closely recapitulate the in vivo TME to better predict CAR T activity. Animal models have contributed immensely to our understanding of human diseases, but the intensive care for the animals and unreliable representation of human biology suggest in vivo models cannot be the sole approach to CAR T cell therapy. On the other hand, in vitro models for CAR T cytotoxic assessment offer valuable insights to mechanistic studies at the single cell level, but they often lack in vivo complexities, inter-individual heterogeneity, or physiologically relevant spatial dimension. Understanding the advantages and limitations of preclinical models and their applications would enable more reliable prediction of better clinical outcomes.

Three-dimensional (3D) liver cell models - a tool for bridging the gap between animal studies and clinical trials when screening liver accumulation and toxicity of nanobiomaterials

Despite the exciting properties and wide-reaching applications of nanobiomaterials (NBMs) in human health and medicine, their translation from bench to bedside is slow, with a predominant issue being liver accumulation and toxicity following systemic administration. In vitro 2D cell-based assays and in vivo testing are the most popular and widely used methods for assessing liver toxicity at pre-clinical stages; however, these fall short in predicting toxicity for NBMs. Focusing on in vitro and in vivo assessment, the accurate prediction of human-specific hepatotoxicity is still a significant challenge to researchers. This review describes the relationship between NBMs and the liver, and the methods for assessing toxicity, focusing on the limitations they bring in the assessment of NBM hepatotoxicity as one of the reasons defining the poor translation for NBMs. We will then present some of the most recent advances towards the development of more biologically relevant in vitro liver methods based on tissue-mimetic 3D cell models and how these could facilitate the translation of NBMs going forward. Finally, we also discuss the low public acceptance and limited uptake of tissue-mimetic 3D models in pre-clinical assessment, despite the demonstrated technical and ethical advantages associated with them.

Patient-Derived Explants as a Precision Medicine Patient-Proximal Testing Platform Informing Cancer Management

Precision medicine approaches that inform clinical management of individuals with cancer are progressively advancing. Patient-derived explants (PDEs) provide a patient-proximal ex vivo platform that can be used to assess sensitivity to standard of care (SOC) therapies and novel agents. PDEs have several advantages as a patient-proximal model compared to current preclinical models, as they maintain the phenotype and microenvironment of the individual tumor. However, the longevity of PDEs is not compatible with the timeframe required to incorporate candidate therapeutic options identified by whole exome sequencing (WES) of the patient’s tumor. This review investigates how PDE longevity varies across tumor streams and how this is influenced by tissue preparation. Improving longevity of PDEs will enable individualized therapeutics testing, and thus contribute to improving outcomes for people with cancer.

The cancer-inhibitory effects of proliferating tumor-residing fibroblasts

Initiation, local progression, and metastasis of cancer are associated with specific morphological, molecular, and functional changes in the extracellular matrix and the fibroblasts within the tumor microenvironment (TME). In the early stages of tumor development, fibroblasts are an obstacle that cancer cells must surpass or nullify to progress. Thus, in early tumor progression, specific signaling from cancer cells activates bio-pathways, which abolish the innate anticancer properties of fibroblasts and convert a high proportion of them to tumor-promoting cancer-associated fibroblasts (CAFs). Following this initial event, a wide spectrum of gene expression changes gradually leads to the development of a stromal fibroblast population with complex heterogeneity, creating fibroblast subtypes with characteristic profiles, which may alternate between being tumor-promotive and tumor-suppressive, topologically and chronologically in the TME. These fibroblast subtypes form the tumor's histological landscape including areas of cancer growth, inflammation, angiogenesis, invasion fronts, proliferating and non-proliferating fibroblasts, cancer-cell apoptosis, fibroblast apoptosis, and necrosis. These features reflect general deregulation of tissue homeostasis within the TME. This review discusses fundamental and current knowledge that has established the existence of anticancer fibroblasts within the various interacting elements of the TME. It is proposed that the maintenance of fibroblast proliferation is an essential parameter for the activation of their anticancer capacity, similar to that by which normal fibroblasts would be activated in wound repair, thus maintaining tissue homeostasis. Encouragement of research in this direction may render new means of cancer therapy and a greater understanding of tumor progression.

Model Selection for the Preclinical Development of New Drug-Radiotherapy Combinations

Radiotherapy plays an essential role in the treatment of more than half of all patients with cancer. In recent decades, advances in devices that deliver radiation and the development of treatment planning software have helped radiotherapy attain precise tumour targeting with minimal toxicity to surrounding tissues. Simultaneously, as more targeted drug therapies are being brought into the market, there has been significant interest in improving cure rates for cancer by adding drugs to radiotherapy to widen the therapeutic window, the difference between normal tissue toxicity and treatment efficacy. The development of new combination therapies will require judicious adaptation of preclinical models that are routinely used for traditional drug discovery. Here we highlight the strengths and weaknesses of each of these preclinical models and discuss how they can be used optimally to identify new and clinically beneficial drug-radiotherapy combinations.

3D Modeling of Epithelial Tumors-The Synergy between Materials Engineering, 3D Bioprinting, High-Content Imaging, and Nanotechnology

The current statistics on cancer show that 90% of all human cancers originate from epithelial cells. Breast and prostate cancer are examples of common tumors of epithelial origin that would benefit from improved drug treatment strategies. About 90% of preclinically approved drugs fail in clinical trials, partially due to the use of too simplified in vitro models and a lack of mimicking the tumor microenvironment in drug efficacy testing. This review focuses on the origin and mechanism of epithelial cancers, followed by experimental models designed to recapitulate the epithelial cancer structure and microenvironment, such as 2D and 3D cell culture models and animal models. A specific focus is put on novel technologies for cell culture of spheroids, organoids, and 3D-printed tissue-like models utilizing biomaterials of natural or synthetic origins. Further emphasis is laid on high-content imaging technologies that are used in the field to visualize in vitro models and their morphology. The associated technological advancements and challenges are also discussed. Finally, the review gives an insight into the potential of exploiting nanotechnological approaches in epithelial cancer research both as tools in tumor modeling and how they can be utilized for the development of nanotherapeutics.

In vitro biomimetic models for glioblastoma-a promising tool for drug response studies

The poor response of glioblastoma to current treatment protocols is a consequence of its intrinsic drug resistance. Resistance to chemotherapy is primarily associated with considerable cellular heterogeneity, and plasticity of glioblastoma cells, alterations in gene expression, presence of specific tumor microenvironment conditions and blood-brain barrier. In an attempt to successfully overcome chemoresistance and better understand the biological behavior of glioblastoma, numerous tri-dimensional (3D) biomimetic models were developed in the past decade. These novel advanced models are able to better recapitulate the spatial organization of glioblastoma in a real time, therefore providing more realistic and reliable evidence to the response of glioblastoma to therapy. Moreover, these models enable the fine-tuning of different tumor microenvironment conditions and facilitate studies on the effects of the tumor microenvironment on glioblastoma chemoresistance. This review outlines current knowledge on the essence of glioblastoma chemoresistance and describes the progress achieved by 3D biomimetic models. Moreover, comprehensive literature assessment regarding the influence of 3D culturing and microenvironment mimicking on glioblastoma gene expression and biological behavior is also provided. The contribution of the blood-brain barrier as well as the blood-tumor barrier to glioblastoma chemoresistance is also reviewed from the perspective of 3D biomimetic models. Finally, the role of mathematical models in predicting 3D glioblastoma behavior and drug response is elaborated. In the future, technological innovations along with mathematical simulations should create reliable 3D biomimetic systems for glioblastoma research that should facilitate the identification and possibly application in preclinical drug testing and precision medicine.

Current status and future outlook for patient-derived cancer models from a rare cancer research perspective

Rare cancers are a group of approximately 200 malignancies with extremely low incidences and with a wide variety of genotypes and phenotypes. Collectively, they are more common than any single malignancy. However, given the small numbers of individuals diagnosed with rare cancers, it is difficult to design clinical trials with sufficient patient numbers. Therefore, few effective anticancer drugs have been developed, and evidence‐based medicine is not always feasible for rare cancers. Consequently, their clinical outcomes are generally poorer. Cancer research requires adequate models that faithfully recapitulate molecular features and reproduce treatment responses of the original tumors. Such models allow us to focus on more efficacious drugs in the clinical studies. For rare cancers, patient‐derived cancer models are particularly important because the enrollment of sufficient patients is rarely attainable within a reasonable period of time. However, extremely few models are available for rare cancers. For example, cell lines and xenografts are available for only a limited number of histological subtypes of sarcomas; therefore, most sarcoma research is performed without such models, and a lack of adequate cancer models causes a lag in therapeutic development. The establishment of novel rare cancer models will dramatically facilitate rare cancer research and treatment development in the near future. This review focuses on the status of patient‐derived rare cancer models and discusses their pivotal problems and possibilities, using sarcomas as a representative rare cancer type. Multi‐institutional collaboration will help address the scarcity of patient‐derived rare cancer models.

Understanding cell-cell communication and signaling in the colorectal cancer microenvironment

Carcinomas are complex heterocellular systems containing epithelial cancer cells, stromal fibroblasts, and multiple immune cell-types. Cell-cell communication between these tumor microenvironments (TME) and cells drives cancer progression and influences response to existing therapies. In order to provide better treatments for patients, we must understand how various cell-types collaborate within the TME to drive cancer and consider the multiple signals present between and within different cancer types. To investigate how tissues function, we need a model to measure both how signals are transferred between cells and how that information is processed within cells. The interplay of collaboration between different cell-types requires cell-cell communication. This article aims to review the current in vitro and in vivo mono-cellular and multi-cellular cultures models of colorectal cancer (CRC), and to explore how they can be used for single-cell multi-omics approaches for isolating multiple types of molecules from a single-cell required for cell-cell communication to distinguish cancer cells from normal cells. Integrating the existing single-cell signaling measurements and models, and through understanding the cell identity and how different cell types communicate, will help predict drug sensitivities in tumor cells and between- and within-patients responses.

Cytokines in various molecular subtypes of breast cancer

INTRODUCTION

Breast cancer is a heterogeneous disease that has multiple molecular and morphological subtypes. Nonetheless, the relation between various molecular subtypes and functional characteristics of a tumor in terms of cytokine secretion remains unknown.

METHODS

We studied spontaneous and mitogen-induced cytokine secretion by invasive breast carcinoma of no special type (IBC NST; cultured tumors and cultured peripheral blood cells), depending on a molecular tumor subtype (where "mitogens" means "polyclonal activators" (PA): phytohemagglutinin p, phytohemagglutinin M, concanavalin A, and Escherichia coli lipopolysaccharide). Enzyme-linked immunosorbent assays were used to determine concentrations of IL-6, IL-8, IL-10, IL-17, IL-18, IL-1β, IL-1Ra, TNF-α, IFN-γ, G-CSF, GM-CSF, VEGF, and MCP-1 in culture supernatants of the tumors and peripheral blood cells.

RESULTS

The luminal B HER2-positive molecular subtype of IBC NST was found to feature the highest spontaneous secretion of IL-6 and IL-8 and the highest mitogen-induced secretion of IL-6, IL-8, IL-1Ra, and TNF-α by tumors; the highest mitogen-induced secretion of IL-2, IL-6, IL-8, IL-1β, TNF-α, IFN-γ, and G-CSF by peripheral blood cells; and the highest cytokine-producing potential (the ratio of mitogen-induced to spontaneous secretion) of peripheral blood cells for the secretion of IL-6, IL-8, and IL-1Ra as compared to other molecular subtypes. The triple-negative subtype of IBC NST was characterized by the lowest cytokine-producing potential of tumors for the secretion of IL-6 and IL-8 as compared to other molecular subtypes as well as a lower "stimulation index of polyclonal activators" (calculated as (cytokine secretion after incubation with PA)/(spontaneous cytokine secretion)) for IL-18 secretion as compared to luminal subtypes. The XYZ correlated with a suppressive effect of PA on cytokine secretion by tumors of the triple-negative molecular subtype.

CONCLUSION

Therefore, our findings indicate that in IBC NST of luminal B HER2-positive and triple-negative molecular subtypes, the cytokine network has distinctive functional features.

[Influence of the HLDF differentiation factor on the production of cytokines by bio-tissues of breast tissue in its non-malignant diseases and in invasive carcinoma of a non-specific type]

We studied the effect of the HLDF differentiation factor on production of cytokines by biopsy samples of nonmalignant breast diseases (ND) and invasive breast carcinoma of no special type (IBC-NST), in the absence and presence of lymphogenic metastasis: IBC-NST patients werw subdivided into groups on the prognostic protocol of the 8th edition of the AJCC committee. Group IA consisted of patients with T1-T2 tumor sizes, and predominantly with positive expression of estrogen and progesterone receptors (ER+/PR+/HER2-); it also included one patient with the HER2+ (ER-/PR-/HER2+) molecular subtype. The IB group was mainly composed of patients with T2 tumor size, with the presence of lymphogenic metastasis (in 8 out of 10) patients and with positive expression of estrogen and progesterone receptors (ER+/PR+/HER2-) and it also included three patients with the HER2+ (ER-/PR-/HER2+) molecular subtype. Group IIA consisted of patients with T1-T2 tumor sizes, mainly with no metastases in the lymph nodes (in 11 out of 12 patients) and with a triple negative molecular subtype. Group IIB included patients with T2 tumor size, the presence of nodal metastasis and the expression of markers of ER-/PR-/HER2 - and ER-/PR-/HER2+. Group IIIA consisted of patients with tumor size T1-T3, with the presence of nodal metastasis and the expression of markers of ER-/PR+/HER2+ and ER-/PR-/HER2+. Group IIIC consisted of patients with T3 tumor size, lymphogenic metastasis, and expression of ER-/PR-/HER2-markers (triple negative molecular subtype). Due to a limited number of patients in the groups IIB, IIIA and IIIC, as well as due to more severe clinical and pathological stages, according to the prognostic Protocol of the 8th edition of the AJCC Committee, they were pooled into group III. Concentrations of IL-2, IL-4, IL-6, IL-8, IL-10, IL-17, IL-18, IL-1β, IL-1Ra, TNF-α, IFN-γ, G-CSF, GM-CSF, VEGF and MCP-1 were assayed in supernatants of biopsy specimens of breast tissue. Results have shown that with IBC-NST, a statistically significantly higher level of spontaneous production (SP) by biopsy specimens of IL-17, IL-18, IFN-γ and VEGF, and a lower level of SP IL-6 as compared with ND. Patients of all clinical and pathological groups showed a high VEGF spontaneous production as compared with ND, while statistically significant differences from patients with ND were not found in IL-17 spontaneous production in group IB patients, and IL-18 spontaneous production were absent in group IA. Only in patients with IA and IB, the IL-6 spontaneous production was lower as compared to ND, and the IL-8 spontaneous production was lower in the IA group. IFN-γ spontaneous production was higher in patients with IBC-NST group IIA as compared with ND. Under the influence of the HLDF differentiation factor, it was found that the parameters of IBC-NST patients were statistically significantly higher in the production of IL-1Ra, IL-17, IL-18 and VEGF, and statistically significantly lower in the production of IL-6 as compared to ND. HLDF had a higher impact on the content of IL-18 in IBC-NST patients than in ND. After HDLF sublimation IL-6 values were lower in patients of groups IA and IB, and HLDF-induced IL-17 production was higher only in patients of group IA. Statistically significant differences in the index of influence of HLDF (IVHLDF), representing ratio of the cytokine concentration in the supernatants of a biopsy specimen stimulated by HLDF to spontaneous cytokine production, were found between ND and IBC-NST in the case of on IFN-γ production, and also in the case of IL-4 production (between patients in the absence and presence of lymphogenic metastasis). IVHLDF for production of IL-6, IL-8 and TNF-α was lower in group IIA patients compared to group IA, and IVHLDF for production of GM-CSF and MCP-1 was lower in group IIA as compared to group III, in addition IVHLDF for MCP-1 products was lower in group IIA as compared to ND. The HLDF effect on the cytokine production by the tumor and its microenvironment was different in ND patients and IBC-NST patients. HDLF suppressed IFN-γ production in the pooled group of IBC-NST patients; HLDF mainly had a suppressive effect on the production of IL-6, IL-8, TNF-α, GM-CSF and MCP-1 in IBC-NST patients of group IIA.

Influence of HLDF Differentiation Factor on Nonspecific Invasive Breast Carcinoma in vitro

The study was carried out on samples of invasive breast carcinoma of no special type from 36 patients aged 48.0 to 62.8 years. The effect of HLDF on nonspecific invasive breast carcinoma was a decrease in the relative content of low-differentiated cells and an increase in the relative content of highly differentiated cells. HLDF did not have a cytotoxic effect leading to the death of low-differentiated cells but promoted promotes the acquisition of a higher degree of differentiation by them. A more pronounced effect of HLDF was observed in more aggressive metastasizing forms of neoplasia, which allows us to consider this differentiation factor as a candidate for use in the differentiation therapy of malignant neoplasms.

[Proteins and immunohistochemical markers of breast diseases]

In this work, we have compared malignant and non-malignant diseases of the mammary gland using 8 proteins: HRG, MUC1, PAI-1, HSP90αA1, CDH1, ERα, PGR and IL-12. Their concentrations in the supernatants of blood cells and breast biopsies were compared in terms of spontaneous production, induced by a polyclonal activator and after exposure to biopsy samples of the HLDF differentiation factor, as well as the indices of the effect of the polyclonal activator and HLDF on the protein production. In addition, the correlation relationships of the above indicators with the expression of markers of the epithelial-mesenchymal transition: collagen type II (CII), β-1 integrin (CD29) and cadherin-E (CDH1) were studied. The study revealed statistically significant differences in the concentration of HRG in the supernatant of blood cells, IL-12 during spontaneous production by biopsy specimens, PGR production of biopsy specimens induced by the polyclonal activator, CDH1 and IL-12 production biopsy specimens exposed to HLDF. According to the influence index of the polyclonal activator and HLDF, statistically significant differences were found for CDH1production. Comparison of non-specific invasive carcinoma biopsy specimens and non-malignant breast diseases by means of the markers of the epithelial-mesenchymal transition revealed statistically significant differences in CD29 expression and the lack of differences in the expression of CDH1 and CII. This indicates the presence of cell atypia in samples of non-malignant breast diseases; it is confirmed by the recognized correlation between the production of certain proteins and the expression of the epithelial-mesenchymal transition markers.

[Relationship between supernatant cytokines and expression of markers of epitelial-mesenchymal transition of invasive breast carcinoma of non-specific lymphynosis type]

The relationship between the content of supernatant cytokines and the expression of non-specific type of markers of epithelial-mesenchymal transition markers in the presence (group II) and the absence of lymphogenous metastasis (group I) were studied in biopsy specimens of mammary invasive breast carcinoma. The concentrations of TNF-α, IFN-γ, G-CSF, GM-CSF, VEGF, MCP-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-17, IL-18, IL-1β and IL-1Ra, as well as the expression of immunohistochemical (IHC) markers of the epithelial-mesenchymal transition - cadherin-E (CDH1), β-1 integrin (CD29) and type II collagen (CII) were assayed. Results have shown that patients of these groups statistically significantly differed in spontaneous production of IL-18 and G-CSF, in terms of the index of the effect of the polyclonal activator on G-CSF production. There was a correlation between the parameter of CII expression in tumor tissue and the production of cytokines by tumor biopsy specimens; it was characteristic of all patients with invasive carcinoma of a non-specific type, and correlations, both direct and reverse between the expression indices of CDH1, CD29 and cytokine production varied depending on the presence or the absence of lymphogenous metastasis. The study revealed the features of the correlation between the production of cytokines by the tumor, its microenvironment and the expression of IHC markers of the epithelial-mesenchymal transition in patients with invasive non-specific breast carcinoma in the presence and absence of lymphogenous metastasis.

Patient-derived explants (PDEs) as a powerful preclinical platform for anti-cancer drug and biomarker discovery

Preclinical models that can accurately predict outcomes in the clinic are much sought after in the field of cancer drug discovery and development. Existing models such as organoids and patient-derived xenografts have many advantages, but they suffer from the drawback of not contextually preserving human tumour architecture. This is a particular problem for the preclinical testing of immunotherapies, as these agents require an intact tumour human-specific microenvironment for them to be effective. In this review, we explore the potential of patient-derived explants (PDEs) for fulfilling this need. PDEs involve the ex vivo culture of fragments of freshly resected human tumours that retain the histological features of original tumours. PDE methodology for anti-cancer drug testing has been in existence for many years, but the platform has not been widely adopted in translational research facilities, despite strong evidence for its clinical predictivity. By modifying PDE endpoint analysis to include the spatial profiling of key biomarkers by using multispectral imaging, we argue that PDEs offer many advantages, including the ability to correlate drug responses with tumour pathology, tumour heterogeneity and changes in the tumour microenvironment. As such, PDEs are a powerful model of choice for cancer drug and biomarker discovery programmes.

[Assessment of the cytokine-producing resource of tumor biopsy samples from patients with invasive carcinoma of no special type and with non-malignant breast diseases]

Breast cancer, in most cases, is a malignant neoplasm associated with infiltration of a tumor with the cells that form its microenvironment and produce various cytokines. The aim of the study was to evaluate the cytokine-producing function of tumor cells and their microenvironment in biopsy specimen of patients with invasive carcinoma of no special type and in patients with benign breast diseases. To assess the cytokine-producing activity of the tumor and its microenvironment, the index of polyclonal activators influence on cytokine production by biopsy specimens of patients with invasive carcinoma of no special type (group I) and in patients with benign breast tumors (group II) was calculated. Group II was further subdivided into group IIa, which included only patients with fibroadenoma, and group IIb, which included the patients with leaf-shaped fibroadenoma, fibroadenomatosis, fibrocystic mastopathy, intraductal papillomatosis, sclerosing adenosis and fibrocystic mastopathy with microcalcifications. The concentrations of IL-2, IL-6, IL-8, IL-10, IL-17, IL-18, IL-1β, IL-1Ra, TNF-α, IFN-γ, G-CSF, GM-CSF, VEGF, and MCP-1 were measured in tumor biopsy supernatants. When comparing groups I and II, higher indices of the polyclonal activators influence on the production of IL-17, IL-18 and TNF-α were observed in patients with benign diseases. Higher indices of the polyclonal activators influence on the production of IL-18, TNF-α, and IL-1β and the ratio of IL1β/IL1Ra were observed in patients with fibroadenoma as compared to those with invasive carcinoma of no special type. There were no significant differences in the indices of the polyclonal activators influence between groups I and IIb. This suggests the existence of changes in the mammary gland in patients of group IIb similar to those present in patients with invasive carcinoma of no special type. Higher indices of polyclonal activators influence on the production of IL-1β, as well as the ratio of IL1β/IL1Ra were observed in the patients of group IIa compared to the patients of group IIb. The results of the study identify the features of the cytokine-producing resource of tumor biopsy specimens in patients with invasive carcinoma of no special type and with benign breast tumors.

Current and Future Horizons of Patient-Derived Xenograft Models in Colorectal Cancer Translational Research

Our poor understanding of the intricate biology of cancer and the limited availability of preclinical models that faithfully recapitulate the complexity of tumors are primary contributors to the high failure rate of novel therapeutics in oncology clinical studies. To address this need, patient-derived xenograft (PDX) platforms have been widely deployed and have reached a point of development where we can critically review their utility to model and interrogate relevant clinical scenarios, including tumor heterogeneity and clonal evolution, contributions of the tumor microenvironment, identification of novel drugs and biomarkers, and mechanisms of drug resistance. Colorectal cancer (CRC) constitutes a unique case to illustrate clinical perspectives revealed by PDX studies, as they overcome limitations intrinsic to conventional ex vivo models. Furthermore, the success of molecularly annotated "Avatar" models for co-clinical trials in other diseases suggests that this approach may provide an additional opportunity to improve clinical decisions, including opportunities for precision targeted therapeutics, for patients with CRC in real time. Although critical weaknesses have been identified with regard to the ability of PDX models to predict clinical outcomes, for now, they are certainly the model of choice for preclinical studies in CRC. Ongoing multi-institutional efforts to develop and share large-scale, well-annotated PDX resources aim to maximize their translational potential. This review comprehensively surveys the current status of PDX models in translational CRC research and discusses the opportunities and considerations for future PDX development.

Clinical Correlation of the Histoculture Drug Response Assay in Gastrointestinal Cancer

The histoculture drug response assay (HDRA) with tumors histocultured on Gelfoam^® was tested for clinical correlation for advanced gastric and colorectal cancer patients. In one study, 29 patients were treated with drugs shown to be ineffective in the HDRA, and all 29 cases showed clinical chemoresistance. In nine patients treated with drugs shown to be effective in the HDRA, six showed clinical chemoresponse and three showed arrest of disease progression. In a study of 32 patients with stage III and IV gastric cancer treated with mitomycin C and 5-fluorouracil (5-FU), the survival rate of 10 patients whose tumors were sensitive to either mitomycin C and/or 5-fluorouracil in the HDRA was significantly better than that of 22 patients whose tumors were insensitive to both drugs in the HDRA. Twenty-nine patients with stage III and IV colorectal cancer without remaining measurable tumor lesions after surgery were treated with fluoropyrimidines adjuvantly. The recurrence-free survival rate of 7 patients whose tumors were sensitive to 5-fluorouracil in the HDRA was significantly better than that of 22 patients whose tumors were insensitive in the HDRA. In a companion study of 128 gastric cancer patients whose tumors were evaluated in the HDRA, the overall and disease-free survival rates of the HDRA-sensitive group were found to be significantly higher than those of the HDRA-resistant group, treated with the same drugs.

A novel extracellular matrix-based leukemia model supports leukemia cells with stem cell-like characteristics

Acute myeloid leukemia (AML) relapse results from the survival of chemotherapy-resistant and quiescent leukemia stem cells (LSC). These LSCs reside in the bone marrow microenvironment, comprised of other cells and extracellular matrix (ECM), which facilitates LSC quiescence through expression of cell adhesion molecules. We used decellularized Wharton's jelly matrix (DWJM), the gelatinous material in the umbilical cord, as a scaffolding material to culture leukemia cells, because it contains many components of the bone marrow extracellular matrix, including collagen, fibronectin, lumican, and hyaluronic acid (HA). Leukemia cells cultured in DWJM demonstrated decreased proliferation without undergoing significant differentiation. After culture in DWJM, these cells also exhibited changes in morphology, acquiring a spindle-shaped appearance, and an increase in the ALDH⁺ cell population. When treated with a high-dose of doxorubicin, leukemia cells in DWJM demonstrated less apoptosis compared with cells in suspension. Serial colony forming unit (CFU) assays indicated that leukemia cells cultured in DWJM showed increased colony-forming ability after both primary and secondary plating. Leukemia cell culture in DWJM was associated with increased N-cadherin expression by flow cytometry. Our data suggest that DWJM could serve as an ECM-based model to study AML stem cell-like cell behavior and chemotherapy sensitivity.

Extracellular vesicles generated by placental tissues ex vivo: A transport system for immune mediators and growth factors

PROBLEM

To study the mechanisms of placenta function and the role of extracellular vesicles (EVs) in pregnancy, it is necessary to develop an ex vivo system that retains placental cytoarchitecture and the primary metabolic aspects, in particular the release of EVs and soluble factors. Here, we developed such a system and investigated the pattern of secretion of cytokines, growth factors, and extracellular vesicles by placental villous and amnion tissues ex vivo.

METHODS OF STUDY

Placental villous and amnion explants were cultured for 2 weeks at the air/liquid interface and their morphology and the released cytokines and EVs were analyzed. Cytokines were analyzed with multiplexed bead assays, and individual EVs were analyzed with recently developed techniques that involved EV capture with magnetic nanoparticles coupled to anti-EV antibodies and flow cytometry.

RESULTS

Ex vivo tissues (i) remained viable and preserved their cytoarchitecture; (ii) maintained secretion of cytokines and growth factors; (iii) released EVs of syncytiotrophoblast and amnion epithelial cell origins that contain cytokines and growth factors.

CONCLUSION

A system of ex vivo placental villous and amnion tissues can be used as an adequate model to study placenta metabolic activity in normal and complicated pregnancies, in particular to characterize EVs by their surface markers and by encapsulated proteins. Establishment and benchmarking the placenta ex vivo system may provide new insight in the functional status of this organ in various placental disorders, particularly regarding the release of EVs and cytokines. Such EVs may have a prognostic value for pregnancy complications.

Recombinant methioninase effectively targets a Ewing's sarcoma in a patient-derived orthotopic xenograft (PDOX) nude-mouse model

Methionine dependence is due to the overuse of methionine for aberrant transmethylation reactions in cancer. Methionine dependence may be the only general metabolic defect in cancer. In order to exploit methionine dependence for therapy, our laboratory previously cloned L-methionine α-deamino-γ-mercaptomethane lyase [EC 4.4.1.11]). The cloned methioninase, termed recombinant methioninase, or rMETase, has been tested in mouse models of human cancer cell lines. Ewing's sarcoma is recalcitrant disease even though development of multimodal therapy has improved patients'outcome. Here we report efficacy of rMETase against Ewing's sarcoma in a patient-derived orthotopic xenograft (PDOX) model. The Ewing's sarcoma was implanted in the right chest wall of nude mice to establish a PDOX model. Eight Ewing's sarcoma PDOX mice were randomized into untreated control group (n = 4) and rMETase treatment group (n = 4). rMETase (100 units) was injected intraperitoneally (i.p.) every 24 hours for 14 consecutive days. All mice were sacrificed on day-15, 24 hours after the last rMETase administration. rMETase effectively reduced tumor growth compared to untreated control. The methionine level both of plasma and supernatants derived from sonicated tumors was lower in the rMETase group. Body weight did not significantly differ at any time points between the 2 groups. The present study is the first demonstrating rMETase efficacy in a PDOX model, suggesting potential clinical development, especially in recalcitrant cancers such as Ewing's sarcoma.

Imaging DNA Repair After UV Irradiation Damage of Cancer Cells in Gelfoam® Histoculture

DNA damage repair in response to UVC irradiation was imaged in cancer cells growing in Gelfoam^® histoculture. UVC-induced DNA damage repair was imaged with green fluorescent protein (GFP) fused to the DNA damage response (DDR)-related binding protein 53BP1 in MiaPaCa-2 human pancreatic cancer cells. Three-dimensional Gelfoam^® histocultures and confocal imaging enabled 53BP1-GFP nuclear foci to be observed within 1 h after UVC irradiation, indicating the onset of DNA damage repair response. Induction of UV-induced 53BP1-GFP focus formation was limited up to a depth of 40 μm in Gelfoam^® histoculture of MiaPaCa-2 cells, indicating this was the depth limit of UVC irradiation.

In Vivo-Like Growth Patterns of Multiple Types of Tumors in Gelfoam® Histoculture

Diverse human tumors obtained directly from surgery or biopsy can grow at high frequency in 3-dimensional Gelfoam^® histoculture for long periods of time and still maintain many of their in vivo properties. The in vivo properties maintained in vitro include 3-dimensional growth; maintenance of tissue organization and structure, such as changes associated with oncogenic transformation; retention of differentiated function; tumorigenicity; and growth of multiple types of cells from a single tumor.

Diagnosis and Pathological Analysis of Patient Cancers by Detection of Proliferating Cells in Gelfoam® Histoculture

Patient tumors grew in Gelfoam^® histoculture with maintenance of tissue architecture, tumor-stromal interaction, and differentiated functions. In this chapter, we review the use of Gelfoam^® histoculture to demonstrate proliferation indices of major solid cancer types explanted directly from surgery. Cell proliferation was visualized by histological autoradiography within the cultured tissues after [³H]thymidine incorporation by the proliferating cells. Epilumination polarization microscopy enables high-resolution imaging of the autoradiography of each cell. The histological status of the cultured tissues can be assessed simultaneously with the proliferation status. Carcinomas were observed to have areas of high epithelial proliferation with quiescent stromal cells. Sarcomas have high proliferation of the cancer cells of mesenchymal organ. Normal tissues can also proliferate at high rates. Mean growth fraction index (GFI) was highest for patient tumors with the pure subtype of small-cell lung cancer than other types of lung cancer.

Expression and Targeting of Tumor Markers in Gelfoam® Histoculture: Potential Individualized Assays for Immuno-Oncology

Tumor-specific antigens are important in the study of tumor biology, tumor diagnosis, and prognosis and as targets for tumor therapy. This chapter reviews patient colon, breast, and ovarian tumors in 3-dimensional Gelfoam^® histoculture maintaining in vivo-like expression of the important tumor antigens, for example TAG-72 and CEA. We have also reviewed that fluorescent antibodies can target tumors in Gelfoam^® histoculture, thereby providing an assay for individual patients for sensitivity to therapeutic antibodies which have become so important in immuno-oncology and other cancer therapies.

Clinical Usefulness of the Histoculture Drug Response Assay for Prostate Cancer and Benign Prostate Hypertrophy (BPH)

The histoculture drug response assay (HDRA) has been adapted to determine androgen sensitivity in Gelfoam histoculture of human benign prostatic tissue as well as prostate cancer. Gelfoam histoculture was used to measure androgen-independent and androgen-dependent growth of benign and malignant prostate tissue. The androgen-sensitivity index was significantly higher in 23 paired specimens of prostate cancer compared to benign prostate hypertrophy (BPH). Genistein decreased the androgen-sensitivity index of BPH and prostate cancer in Gelfoam^® histoculture in a dose-dependent manner.

Clinical Correlation of the Histoculture Drug Response Assay for Head and Neck Cancer

Gelfoam^® histoculture was utilized to develop the histoculture drug response assay (HDRA) for head and neck cancer. Specimens of head and neck tumors were evaluated for sensitivity to the following drugs: cisplatinum (CDDP), 5-fluorouracil (5-FU), and the combination of CDDP and 5-FU. In the first clinical study at UCSD, 10 of 12 patients with tumors that were drug sensitive in Gelfoam^® histoculture had either complete or partial response clinically. Comparisons of HDRA results, obtained with [³H]thymidine incorporation as the endpoint were made with clinical responses, i.e., complete response, partial response, or no response. The overall accuracy of the HDRA was 74% in this correlative clinical trial; the predictive positive value was 83%, the sensitivity was 71%, and the specificity was 78%. Seven of 11 patients with HDRA-resistant tumors demonstrated no response for a predictive negative value of 64%. In a subsequent study at Memorial Sloan Kettering Cancer Center, tumor specimens from 41 to 42 patients undergoing treatment for head and neck cancer were successfully evaluated by the HDRA. The histocultured tumors were treated with 5-FU and/or CDDP and a control group received no drug treatment. After completion of drug treatment, the relative cell survival in the tumors was determined using the MTT endpoint. Sensitivity was defined as a tumor inhibition rate (IR) of greater than 30%. Survival comparisons were performed using the generalized Wilcoxon test for the comparison of Kaplan-Meier survival curves. Resistance to 5-FU was observed in 13 cases (32%), to CDDP in 13 cases (32%), and to both agents in 11 cases (27%). The 2-year cause-specific survival was significantly greater for patients sensitive to 5-FU than patients who were resistant (85% vs. 64%), CDDP (86% vs. 64%), or both agents (85% vs. 63%). These results demonstrate the clinical usefulness of the HDRA for head and neck cancer.

Comprehensive high-throughput image analysis for therapeutic efficacy of architecturally complex heterotypic organoids

Bioengineered three-dimensional (3D) tumor models that incorporate heterotypic cellular communication are gaining interest as they can recapitulate key features regarding the intrinsic heterogeneity of cancer tissues. However, the architectural complexity and heterogeneous contents associated with these models pose a challenge for toxicological assays to accurately report treatment outcomes. To address this issue, we describe a comprehensive image analysis procedure for structurally complex organotypic cultures (CALYPSO) applied to fluorescence-based assays to extract multiparametric readouts of treatment effects for heterotypic tumor cultures that enables advanced analyses. The capacity of this approach is exemplified on various 3D models including adherent/suspension, mono-/heterocellular cultures and several disease types. The subsequent analysis revealed specific morphological effects of oxaliplatin chemotherapy, radiotherapy, and photodynamic therapy. The procedure can be readily implemented in most laboratories to facilitate high-throughput toxicological screening of pharmaceutical agents and treatment regimens on organotypic cultures of human disease to expedite drug and therapy development.

Three-dimensional cell culture: A powerful tool in tumor research and drug discovery

In previous years, three-dimensional (3D) cell culture technology has become a focus of research in tumor cell biology, using a variety of methods and materials to mimic the in vivo microenvironment of cultured tumor cells ex vivo. These 3D tumor cells have demonstrated numerous different characteristics compared with traditional two-dimensional (2D) culture. 3D cell culture provides a useful platform for further identifying the biological characteristics of tumor cells, particularly in the drug sensitivity area of the key points of translational medicine. It promises to be a bridge between traditional 2D culture and animal experiments, and is of great importance for further research in the field of tumor biology. In the present review, previous 3D cell culture applications, focusing on anti-tumor drug susceptibility testing, are summarized.

Precision Oncology: The Road Ahead

Current efforts in precision oncology largely focus on the benefit of genomics-guided therapy. Yet, advances in sequencing techniques provide an unprecedented view of the complex genetic and nongenetic heterogeneity within individual tumors. Herein, we outline the benefits of integrating genomic and transcriptomic analyses for advanced precision oncology. We summarize relevant computational approaches to detect novel drivers and genetic vulnerabilities, suitable for therapeutic exploration. Clinically relevant platforms to functionally test predicted drugs/drug combinations for individual patients are reviewed. Finally, we highlight the technological advances in single cell analysis of tumor specimens. These may ultimately lead to the development of next-generation cancer drugs, capable of tackling the hurdles imposed by genetic and phenotypic heterogeneity on current anticancer therapies.

Unique insight into microenvironmental changes in colorectal cancer: Ex vivo assessment of matrix metalloprotease-mediated molecular changes in human colorectal tumor tissue and corresponding non-neoplastic adjacent tissue

Matrix metalloprotease (MMP)-mediated tissue remodeling is one of the malignant changes driving colorectal cancer. Measurement of altered MMP expression/activity is not sufficient to fully understand the effect of MMP-mediated tissue remodeling. Biomarkers are required that specifically reflect the dynamic processes of the MMP-mediated degradation of signature proteins from colorectal tissue. The aim of the present study was to profile and characterize the release of MMP-degraded type III collagen (C3M) and citrullinated and MMP-degraded vimentin (VICM) from tumor tissue and corresponding non-neoplastic adjacent tissue (NAT) in a human colorectal cancer ex vivo model. Colorectal tumor tissue and NAT biopsies from tissue removed during resection of colorectal cancer patients (n=13) were cut into pieces of 2 mm² and cultured for 24 h in growth medium. C3M and VICM were evaluated by ELISA. As part of the characterization, C3M was determined subsequent to the tumor tissue being cleaved with recombinant MMP-2/-9 and trypsin. C3M was generated by MMP-2/-9, but not by trypsin. In addition, the level of C3M was significantly elevated in the conditioned medium from tumor tissues (3.7 ng/ml) compared with that observed in the conditioned medium from the NATs (2.2 ng/ml) and in the growth medium alone (1.9 ng/ml). The level of VICM was significantly elevated in the tumor tissues (0.51 ng/ml) and NATs (0.52 ng/ml) compared with that in the growth medium alone (0.03 ng/ml). No differences were detected between the tumor tissues and NATs. No correlation was observed between biomarker levels from the tumor tissue and corresponding NAT, and the biomarker levels did not correlate with tumor stage. In conclusion, the present study provided support of the concept that C3M and VICM are applicable as tools to investigate dynamic tissue changes of colorectal tumor tissue and corresponding NAT. By the assessment of these specific MMP-mediated molecular changes, the present study provides novel and relevant insight into the dynamic changes of colorectal tumor tissue and corresponding NAT.

Ex Vivo Explant Cultures of Non-Small Cell Lung Carcinoma Enable Evaluation of Primary Tumor Responses to Anticancer Therapy

To improve treatment outcomes in non-small cell lung cancer (NSCLC), preclinical models that can better predict individual patient response to novel therapies are urgently needed. Using freshly resected tumor tissue, we describe an optimized ex vivo explant culture model that enables concurrent evaluation of NSCLC response to therapy while maintaining the tumor microenvironment. We found that approximately 70% of primary NSCLC specimens were amenable to explant culture with tissue integrity intact for up to 72 hours. Variations in cisplatin sensitivity were noted with approximately 50% of cases responding ex vivo Notably, explant responses to cisplatin correlated significantly with patient survival (P = 0.006) irrespective of tumor stage. In explant tissue, cisplatin-resistant tumors excluded platinum ions from tumor areas in contrast to cisplatin-sensitive tumors. Intact TP53 did not predict cisplatin sensitivity, but a positive correlation was observed between cisplatin sensitivity and TP53 mutation status (P = 0.003). Treatment of NSCLC explants with the targeted agent TRAIL revealed differential sensitivity with the majority of tumors resistant to single-agent or cisplatin combination therapy. Overall, our results validated a rapid, reproducible, and low-cost platform for assessing drug responses in patient tumors ex vivo, thereby enabling preclinical testing of novel drugs and helping stratify patients using biomarker evaluation. Cancer Res; 77(8); 2029-39. ©2017 AACR.

PEG-peptide hydrogels reveal differential effects of matrix microenvironmental cues on melanoma drug sensitivity

Metastatic melanoma is highly drug resistant, though the exact mechanisms of this resistance are not completely understood. One method to study melanoma drug responsiveness in vitro is through the use of multicellular spheroids, which have been found to exhibit decreased drug sensitivity compared to traditional 2D culture on various substrates. Because it is unclear whether dimensionality, cell-matrix interactions, and/or cell-cell contacts may influence melanoma drug responsiveness, we utilized a synthetic PEG-based hydrogel to compare the responses of cells cultured on top of or encapsulated within matrices with the same adhesive ligand density, polymer density, and material properties. We found that depending on the stage of progression at which the melanoma cells were derived, the cells responded differently to PLX4032 treatment, a commercially available melanoma drug. In particular, early stage WM35 cells were insensitive to dimensionality (i.e., 2D versus 3D culture), while metastatic A375 cells exhibited decreased responsiveness in 3D compared to 2D. To further understand the role of the microenvironment in early stage melanoma cells, we tested single WM35 cells and multicellular WM35 spheroids in 3D. The results revealed that the spheroids were similarly sensitive to PLX4032 treatment compared to single cell encapsulations. Collectively, this study implicates the role that 3D microenvironments (i.e., dimensionality) may play in observed melanoma drug responsiveness, and the potential lack of influence of cell-matrix interactions over cell-cell contacts in early stages of melanoma resistance to PLX4032-induced apoptosis.

Bringing 3D tumor models to the clinic - predictive value for personalized medicine

Current decision-guiding algorithms in cancer drug treatment are based on decades of research and numerous clinical trials. For the majority of patients, this data is successfully applied for a systemic disease management. For a number of patients however, treatment stratification according to clinically based risk criteria will not be sufficient. The most effective treatment options are ideally identified prior to the start of clinical drug therapy. This review will discuss the implementation of three-dimensional (3D) cell culture models as a preclinical testing paradigm for the efficacy of clinical cancer treatment. Patient tumor-derived cells in 3D cultures duplicate the individual tumor microenvironment with a minimum of confounding factors. Clinical implementation of such personalized tumor models requires a high quality of methodological and clinical validation comparable to other biomarkers. A non-systematic literature search demonstrated the small number of prospective studies that have been conducted in this area of research. This may explain the current reluctance of many physicians and insurance providers in implementing this type of assay into the clinical diagnostic routine despite potential benefit for patients. Achieving valid and reproducible results with a high level of evidence is central in improving the acceptance of preclinical 3D tumor models.

Efficacy of a Cell-Cycle Decoying Killer Adenovirus on 3-D Gelfoam®-Histoculture and Tumor-Sphere Models of Chemo-Resistant Stomach Carcinomatosis Visualized by FUCCI Imaging

Stomach cancer carcinomatosis peritonitis (SCCP) is a recalcitrant disease. The goal of the present study was to establish an in vitro-in vivo-like imageable model of SCCP to develop cell-cycle-based therapeutics of SCCP. We established 3-D Gelfoam^® histoculture and tumor-sphere models of SCCP. FUCCI-expressing MKN-45 stomach cancer cells were transferred to express the fluorescence ubiquinized cell-cycle indicator (FUCCI). FUCCI-expressing MKN-45 cells formed spheres on agarose or on Gelfoam^® grew into tumor-like structures with G₀/G₁ cancer cells in the center and S/G₂ cancer cells located in the surface as indicated by FUCCI imaging when the cells fluoresced red or green, respectively. We treated FUCCI-expressing cancer cells forming SCCP tumors in Gelfoam^® histoculture with OBP-301, cisplatinum (CDDP), or paclitaxel. CDDP or paclitaxel killed only cycling cancer cells and were ineffective against G₁/G₂ MKN-45 cells in tumors growing on Gelfoam^®. In contrast, the telomerase-dependent adenovirus OBP-301 decoyed the MKN-45 cells in tumors on Gelfoam^® to cycle from G₀/G₁ phase to S/G₂ phase and reduced their viability. CDDP- or paclitaxel-treated MKN-45 tumors remained quiescent and did not change in size. In contrast, OB-301 reduced the size of the MKN-45 tumors on Gelfoam^®. We examined the cell cycle-related proteins using Western blotting. CDDP increased the expression of p53 and p21 indicating cell cycle arrest. In contrast, OBP-301 decreased the expression of p53 and p21 Furthermore, OBP-301 increased the expression of E2F and pAkt as further indication of cell cycle decoy. This 3-D Gelfoam^® histoculture and FUCCI imaging are powerful tools to discover effective therapy of SCCP such as OBP-301.

Protocols for Gelfoam(®) Histoculture of Hair-Shaft-Producing Mouse Whisker Follicles Containing Nestin-GFP-Expressing Hair-Follicle-Associated Pluripotent (HAP) Stem Cells for Long Time Periods

Gelfoam(®)-histocultured whisker follicles from nestin-driven-green fluorescent protein (ND-GFP) mice produced growing pigmented and unpigmented hair shafts. Hair-shaft length increased rapidly by day 4 and continued growing until at least day 12 after which the hair-shaft length was constant. By day 63 in histoculture, the number of ND-GFP hair follicle-associated pluripotent (HAP) stem cells increased significantly and the follicles were intact. Three-dimensional Gelfoam(®) histoculture of hair follicles can provide a very long-term period for evaluating novel agents to promote hair growth.

Three-dimensional culture systems in cancer research: Focus on tumor spheroid model

Cancer cells propagated in three-dimensional (3D) culture systems exhibit physiologically relevant cell-cell and cell-matrix interactions, gene expression and signaling pathway profiles, heterogeneity and structural complexity that reflect in vivo tumors. In recent years, development of various 3D models has improved the study of host-tumor interaction and use of high-throughput screening platforms for anti-cancer drug discovery and development. This review attempts to summarize the various 3D culture systems, with an emphasis on the most well characterized and widely applied model - multicellular tumor spheroids. This review also highlights the various techniques to generate tumor spheroids, methods to characterize them, and its applicability in cancer research.

Effect of polyclonal activators on cytokine production by blood cells and by malignant breast cancer cells

The production of cytokines by peripheral blood cells and biopsy specimens of tumors stimulated by polyclonal activators (PAs) was evaluated in 34 patients with invasive ductal breast carcinoma using enzyme-linked immunosorbent assay (ELISA). Positive correlation between the stimulation index of polyclonal activators (SIPA) for IL-18 production by the tumor and the relative content of poorly differentiated cells was revealed. The latter, in turn, was positively correlated with the numbers of normal and pathologic mitoses and the degree of malignancy. Cancer cells can produce IL-18, which is involved in the process of angiogenesis, stimulates invasion and metastasis. Decrease in SIPA for the production of IL-6 and GCSF by peripheral blood cells could serve as an indicator of malignant progression in invasive ductal breast carcinoma.

Defining the optimal murine models to investigate immune checkpoint blockers and their combination with other immunotherapies

The recent success of checkpoint blockers to treat cancer has demonstrated that the immune system is a critical player in the war against cancer. Historically, anticancer therapeutics have been tested in syngeneic mouse models (with a fully murine immune system) or in immunodeficient mice that allow the engraftment of human xenografts. Animal models with functioning human immune systems are critically needed to more accurately recapitulate the complexity of the human tumor microenvironment. Such models are integral to better predict tumor responses to both immunomodulatory agents and directly antineoplastic therapies. In this regard, the development of humanized models is a promising, novel strategy that offers the possibility of testing checkpoint blockers' capacity and their combination with other antitumor drugs. In this review, we discuss the strengths and weaknesses of the available animal models regarding their capacity to evaluate checkpoint blockers and checkpoint blocker-based combination immunotherapy.

Cancer cells mimic in vivo spatial-temporal cell-cycle phase distribution and chemosensitivity in 3-dimensional Gelfoam® histoculture but not 2-dimensional culture as visualized with real-time FUCCI imaging

The phase of the cell cycle can determine whether a cancer cell can respond to a given drug. We previously reported monitoring of real-time cell cycle dynamics of cancer cells throughout a live tumor, intravitally in live mice, using a fluorescence ubiquitination-based cell-cycle indicator (FUCCI). Approximately 90% of cancer cells in the center and 80% of total cells of an established tumor are in G0/G1 phase. Longitudinal real-time imaging demonstrated that cytotoxic agents killed only proliferating cancer cells at the surface and, in contrast, had little effect on quiescent cancer cells, which are the vast majority of an established tumor. Moreover, resistant quiescent cancer cells restarted cycling after cessation of chemotherapy. These results suggested why most drugs currently in clinical use, which target cancer cells in S/G2/M, are mostly ineffective on solid tumors. In the present report, we used FUCCI imaging and Gelfoam® collagen-sponge-gel histoculture, to demonstrate in real time, that the cell-cycle phase distribution of cancer cells in Gelfoam® and in vivo tumors is highly similar, whereby only the surface cells proliferate and interior cells are quiescent in G0/G1. This is in contrast to 2D culture where most cancer cells cycle. Similarly, the cancer cells responded similarly to toxic chemotherapy in Gelfoam® culture as in vivo, and very differently than cancer cells in 2D culture which were much more chemosensitive. Gelfoam® culture of FUCCI-expressing cancer cells offers the opportunity to image the cell cycle of cancer cells continuously and to screen for novel effective therapies to target quiescent cells, which are the majority in a tumor and which would have a strong probability to be effective in vivo.

Drug sensitivity testing platforms for gastric cancer diagnostics

Gastric cancer diagnostics has traditionally been histomorphological and primarily the domain of surgical pathologists. Although there is an increasing usage of molecular and genomic techniques for clinical diagnostics, there is an emerging field of personalised drug sensitivity testing. In this review, we describe the various personalised drug sensitivity testing platforms and discuss the challenges facing clinical adoption of these assays for gastric cancer.