Developing Organoids from Ovarian Cancer as Experimental and Preclinical Models

Kinase Inhibitors in the Treatment of Ovarian Cancer: Current State and Future Promises

Ovarian cancer is the deadliest gynecological cancer, the high-grade serous ovarian carcinoma (HGSC) being its most common and most aggressive form. Despite the latest therapeutical advancements following the introduction of vascular endothelial growth factor receptor (VEGFR) targeting angiogenesis inhibitors and poly-ADP-ribose-polymerase (PARP) inhibitors to supplement the standard platinum- and taxane-based chemotherapy, the expected overall survival of HGSC patients has not improved significantly from the five-year rate of 42%. This calls for the development and testing of more efficient treatment options. Many oncogenic kinase-signaling pathways are dysregulated in HGSC. Since small-molecule kinase inhibitors have revolutionized the treatment of many solid cancers due to the generality of the increased activation of protein kinases in carcinomas, it is reasonable to evaluate their potential against HGSC. Here, we present the latest concluded and on-going clinical trials on kinase inhibitors in HGSC, as well as the recent work concerning ovarian cancer patient organoids and xenograft models. We discuss the potential of kinase inhibitors as personalized treatments, which would require comprehensive assessment of the biological mechanisms underlying tumor spread and chemoresistance in individual patients, and their connection to tumor genome and transcriptome to establish identifiable subgroups of patients who are most likely to benefit from a given therapy.

Combined inhibition of BADSer99 phosphorylation and PARP ablates models of recurrent ovarian carcinoma

Background

Poly (ADP-ribose) polymerase inhibitors (PARPis) have been approved for the treatment of recurrent epithelial ovarian cancer (EOC), regardless of BRCA status or homologous recombination repair deficiency. However, the low response of platinum-resistant EOC, the emergence of resistance in BRCA-deficient cancer, and therapy-associated toxicities in patients limit the clinical utility of PARPis in recurrent EOC.

Methods

The association of phosphorylated (p) BADS99 with clinicopathological parameters and survival outcomes in an EOC cohort was assessed by immunohistochemistry. The therapeutic synergy, and mechanisms thereof, between a pBADS99 inhibitor and PARPis in EOC was determined in vitro and in vivo using cell line and patient-derived models.

Results

A positive correlation between pBADS99 in EOC with higher disease stage and poorer survival is observed. Increased pBADS99 in EOC cells is significantly associated with BRCA-deficiency and decreased Cisplatin or Olaparib sensitivity. Pharmacological inhibition of pBADS99 synergizes with PARPis to enhance PARPi IC₅₀ and decreases survival, foci formation, and growth in ex vivo culture of EOC cells and patient-derived organoids (PDOs). Combined inhibition of pBADS99 and PARP in EOC cells or PDOs enhances DNA damage but impairs PARPi stimulated DNA repair with a consequent increase in apoptosis. Inhibition of BADS99 phosphorylation synergizes with Olaparib to suppress the xenograft growth of platinum-sensitive and resistant EOC. Combined pBADS99-PARP inhibition produces a complete response in a PDX derived from a patient with metastatic and chemoresistant EOC.

Conclusions

A rational and efficacious combination strategy involving combined inhibition of pBADS99 and PARP for the treatment of recurrent EOC is presented.

Ovarian cancer is difficult to successfully treat because it often recurs as the cancer becomes resistant to drugs used to treat it. As such, new drugs or combinations of drugs are needed to treat patients with recurrent ovarian cancer. Here, a drug combination is reported that is effective in experimental models of ovarian cancer, including those derived from patients. The combination approach uses drugs that have previously been approved for use in patients, known as PARP inhibitors, and another drug to inhibit cancer cell survival by targeting activation of a specific protein involved in cancer cell survival. The net effect of this drug combination in ovarian cancer models is greater than the sum of the drugs used individually. With further testing, this combination may offer a potential strategy to treat patients with recurrent ovarian cancer.

Zhang et al. test the therapeutic potential of an inhibitor of BAD phosphorylation, NPB, in epithelial ovarian cancer. The authors show that the small molecule synergises with PARP inhibition to kill patient-derived ovarian cancer organoids and suppress the growth of xenograft tumours, including a cisplatin-resistant model.

3D organ-on-a-chip: The convergence of microphysiological systems and organoids

Medicine today faces the combined challenge of an increasing number of untreatable diseases and fewer drugs reaching the clinic. While pharmaceutical companies have increased the number of drugs in early development and entering phase I of clinical trials, fewer actually successfully pass phase III and launch into the market. In fact, only 1 out of every 9 drugs entering phase I will launch. In vitro preclinical tests are used to predict earlier and better the potential of new drugs and thus avoid expensive clinical trial phases. The most recent developments favor 3D cell culture and human stem cell biology. These 3D humanized models known as organoids better mimic the 3D tissue architecture and physiological cell behavior of healthy and disease models, but face critical issues in production such as small-scale batches, greater costs (when compared to monolayer cultures) and reproducibility. To become the gold standard and most relevant biological model for drug discovery and development, organoid technology needs to integrate biological culture processes with advanced microtechnologies, such as microphysiological systems based on microfluidics technology. Microphysiological systems, known as organ-on-a-chip, mimic physiological conditions better than conventional cell culture models since they can emulate perfusion, mechanical and other parameters crucial for tissue and organ physiology. In addition, they reduce labor cost and human error by supporting automated operation and reduce reagent use in miniaturized culture systems. There is thus a clear advantage in combining organoid culture with microsystems for drug development. The main objective of this review is to address the recent advances in organoids and microphysiological systems highlighting crucial technologies for reaching a synergistic strategy, including bioprinting.

Single-cell and bulk RNA sequencing reveal ligands and receptors associated with worse overall survival in serous ovarian cancer

Background

Serous ovarian carcinoma is the most frequent histological subgroup of ovarian cancer and the leading cause of death among gynecologic tumors. The tumor microenvironment and cancer-associated fibroblasts (CAFs) have a critical role in the origin and progression of cancer. We comprehensively characterized the crosstalk between CAFs and ovarian cancer cells from malignant fluids to identify specific ligands and receptors mediating intercellular communications and disrupted pathways related to prognosis and therapy response.

Methods

Malignant fluids of serous ovarian cancer, including tumor-derived organoids, CAFs-enriched (eCAFs), and malignant effusion cells (no cultured) paired with normal ovarian tissues, were explored by RNA-sequencing. These data were integrated with single-cell RNA-sequencing data of ascites from ovarian cancer patients. The most relevant ligand and receptor interactions were used to identify differentially expressed genes with prognostic values in ovarian cancer.

Results

CAF ligands and epithelial cancer cell receptors were enriched for PI3K-AKT, focal adhesion, and epithelial-mesenchymal transition signaling pathways. Collagens, MIF, MDK, APP, and laminin were detected as the most significant signaling, and the top ligand-receptor interactions THBS2/THBS3 (CAFs)—CD47 (cancer cells), MDK (CAFs)—NCL/SDC2/SDC4 (cancer cells) as potential therapeutic targets. Interestingly, 34 genes encoding receptors and ligands of the PI3K pathway were associated with the outcome, response to treatment, and overall survival in ovarian cancer. Up-regulated genes from this list consistently predicted a worse overall survival (hazard ratio > 1.0 and log-rank P < 0.05) in two independent validation cohorts.

Conclusions

This study describes critical signaling pathways, ligands, and receptors involved in the communication between CAFs and cancer cells that have prognostic and therapeutic significance in ovarian cancer.

Harnessing preclinical models for the interrogation of ovarian cancer

Ovarian cancer (OC) is a heterogeneous malignancy with various etiology, histopathology, and biological feature. Despite accumulating understanding of OC in the post-genomic era, the preclinical knowledge still undergoes limited translation from bench to beside, and the prognosis of ovarian cancer has remained dismal over the past 30 years. Henceforth, reliable preclinical model systems are warranted to bridge the gap between laboratory experiments and clinical practice. In this review, we discuss the status quo of ovarian cancer preclinical models which includes conventional cell line models, patient-derived xenografts (PDXs), patient-derived organoids (PDOs), patient-derived explants (PDEs), and genetically engineered mouse models (GEMMs). Each model has its own strengths and drawbacks. We focus on the potentials and challenges of using these valuable tools, either alone or in combination, to interrogate critical issues with OC.

Single-Cell RNA Sequencing Reveals the Tissue Architecture in Human High-Grade Serous Ovarian Cancer

PURPOSE

The heterogeneity of high-grade serous ovarian cancer (HGSOC) is not well studied, which severely hinders clinical treatment of HGSOC. Thus, it is necessary to characterize the heterogeneity of HGSOC within its tumor microenvironment (TME).

EXPERIMENTAL DESIGN

The tumors of 7 treatment-naïve patients with HGSOC at early or late stages and five age-matched nonmalignant ovarian samples were analyzed by deep single-cell RNA sequencing (scRNA-seq).

RESULTS

A total of 59,324 single cells obtained from HGSOC and nonmalignant ovarian tissues were sequenced by scRNA-seq. Among those cells, tumor cells were characterized by a set of epithelial-to-mesenchymal transition (EMT)-associated gene signatures, in which a combination of NOTCH1, SNAI2, TGFBR1, and WNT11 was further selected as a genetic panel to predict the poor outcomes of patients with HGSOC. Matrix cancer-associated fibroblasts (mCAF) expressing α-SMA, vimentin, COL3A, COL10A, and MMP11 were the dominant CAFs in HGSOC tumors and could induce EMT properties of ovarian cancer cells in the coculture system. Specific immune cell subsets such as C7-APOBEC3A M1 macrophages, CD8+ TRM, and TEX cells were preferentially enriched in early-stage tumors. In addition, an immune coinhibitory receptor TIGIT was highly expressed on CD8+ TEX cells and TIGIT blockade could significantly reduce ovarian cancer tumor growth in mouse models.

CONCLUSIONS

Our transcriptomic results analyzed by scRNA-seq delineate an ecosystemic landscape of HGSOC at early or late stages with a focus on its heterogeneity with TME. The major applications of our findings are a four-EMT gene model for prediction of HGSOC patient outcomes, mCAFs' capability of enhancing ovarian cancer cell invasion and potential therapeutic value of anti-TIGIT treatment.

Advanced Cellular Models for Preclinical Drug Testing: From 2D Cultures to Organ-On-A-Chip Technology

Simple Summary

Novel strategies that aim at personalizing cancer therapy are in rapid evolution. In the past decade, new methods to test for the efficacy of either standard-of-care medicines or novel targeted compounds have been implemented. In this review, we introduce the reader to experimental studies that employ patient-derived material to produce spheroids, organoids, or organs-on-a-chip as platforms that allow a more accurate representation of cancer complexity compared to bidimensional cell cultures. We discuss on the versatility and reliability of these model systems, provide evidence of their usage in drug screenings, and describe potential downfalls. The open question is whether or not tumor mimicry in vitro will be, in the near future, advanced enough to prospectively inform about treatment outcome on a certain patient.

Abstract

Cancer is a complex disease arising from a homeostatic imbalance of cell-intrinsic and microenvironment-related mechanisms. A multimodal approach to treat cancer that includes surgery, chemotherapy, and radiation therapy often fails in achieving tumor remission and produces unbearable side effects including secondary malignancies. Novel strategies have been implemented in the past decades in order to replace conventional chemotherapeutics with targeted, less toxic drugs. Up to now, scientists have relied on results achieved in animal research before proceeding to clinical trials. However, the high failure rate of targeted drugs in early phase trials leaves no doubt about the inadequacy of those models. In compliance with the need of reducing, and possibly replacing, animal research, studies have been conducted in vitro with advanced cellular models that more and more mimic the tumor in vivo. We will here review those methods that allow for the 3D reconstitution of the tumor and its microenvironment and the implementation of the organ-on-a-chip technology to study minimal organ units in disease progression. We will make specific reference to the usability of these systems as predictive cancer models and report on recent applications in high-throughput screenings of innovative and targeted drug compounds.

Neuregulin-1 signaling regulates cytokines and chemokines expression and secretion in granulosa cell

BACKGROUND

Granulosa cells (GCs) are multilayered somatic cells within the follicle that provide physical support and microenvironment for the developing oocyte. In recent years, the role of Neuregulin-1 (NRG1), a member of the EGF-like factor family, has received considerable attention due to its neurodevelopmental and cardiac function. However, the exact physiological role of NRG1 in GC is mainly unknown. In order to confirm that NRG1 plays a regulatory role in rat GC functions, endogenous NRG1-knockdown studies were carried out in GCs using RNA interference methodology.

RESULTS

Knockdown of NRG1 in GCs resulted in the enhanced expression and secretion of the cytokines and chemokines. In addition, the phosphorylation of PI3K/Akt/ERK1/2 was significantly low in GCs under these experimental conditions. Moreover, in vitro experimental studies suggest that tumor necrosis factor-α (TNFα) treatment causes the physical destruction of GCs by activating caspase-3/7 activity. In contrast, exogenous NRG1 co-treatment of GCs delayed the onset of TNFα-induced apoptosis and inhibited the activation of caspase-3/7 activity. Furthermore, current experimental studies suggest that gonadotropins promote differential expression of NRG1 and ErbB3 receptors in GCs of the antral follicle. Interestingly, NRG1 and ErbB3 were intensely co-localized in the mural and cumulus GCs and cumulus-oocyte complex of pre-ovulatory follicles in the estrus stage.

CONCLUSIONS

The present studies suggest that gonadotropins-dependent NRG1-signaling in GCs may require the balance of the cytokines and chemokines expression and secretion, ultimately which may be supporting the follicular maturation and oocyte competence for ovulation and preventing follicular atresia.

Gene expressions and their significance in organoid cultures obtained from breast cancer patient-derived biopsies

Gene expression changes are one of the hallmarks of malignant cells and such changes in specific genes have been identified for a variety of human cancers. Such an association in gene expression changes becomes very significant for breast cancers due to the genetic heterogeneity seen in such cancers. It is due to such genetic implication that breast cancers are classified into several subtypes; based on the expression and the magnitude of expression of estrogen and progesterone receptor genes. Changes in the expression of ERBB2, ESR1, PLAU, MUC1, PGR, and TP53 are implicated in breast cancers. Of the various models available for cancer research, organoid cultures from patient-derived biopsies are being considered as the most relevant for invitro testing. Organoid cultures derived from patient biopsies mitigate several limitations of other commonly available models such as cancer cell lines. Such organoids retain the functional physiology of solid tumors which include gene expression. Also, utilizing patient derived organoids for in vitro testing paves way for personalized medicine which greatly enhances the effectiveness of cancer therapy for individuals. We present the genes implicated in breast cancers, the ways in which organoids can be derived from breast cancer biopsies and their applications for gene expression studies.

Preclinical models of epithelial ovarian cancer: practical considerations and challenges for a meaningful application

Despite many improvements in ovarian cancer diagnosis and treatment, until now, conventional chemotherapy and new biological drugs have not been shown to cure the disease, and the overall prognosis remains poor. Over 90% of ovarian malignancies are categorized as epithelial ovarian cancers (EOC), a collection of different types of neoplasms with distinctive disease biology, response to chemotherapy, and outcome. Advances in our understanding of the histopathology and molecular features of EOC subtypes, as well as the cellular origins of these cancers, have given a boost to the development of clinically relevant experimental models. The overall goal of this review is to provide a comprehensive description of the available preclinical investigational approaches aimed at better characterizing disease development and progression and at identifying new therapeutic strategies. Systems discussed comprise monolayer (2D) and three-dimensional (3D) cultures of established and primary cancer cell lines, organoids and patient-derived explants, animal models, including carcinogen-induced, syngeneic, genetically engineered mouse, xenografts, patient-derived xenografts (PDX), humanized PDX, and the zebrafish and the laying hen models. Recent advances in tumour-on-a-chip platforms are also detailed. The critical analysis of strengths and weaknesses of each experimental model will aid in identifying opportunities to optimize their translational value.

Equine Oviductal Organoid Generation and Cryopreservation

Organoids are a type of three-dimensional (3D) cell culture that more closely mimic the in vivo environment and can be maintained in the long term. To date, oviductal organoids have only been reported in laboratory mice, women, and cattle. Equine oviductal organoids were generated and cultured for 42 days (including 3 passages and freeze-thawing at passage 1). Consistent with the reports in mouse and human oviductal organoids, the equine oviductal organoids revealed round cell clusters with a central lumen. Developing a 3D model of the mare oviduct may allow for an increased understanding of their normal physiology, including hormonal regulation. These organoids may provide an environment that mimics the in vivo equine oviduct and facilitate improved in vitro embryo production in equids.

Application of Patient-Derived Cancer Organoids to Personalized Medicine

Cell models are indispensable for the research and development of cancer therapies. Cancer medications have evolved with the establishment of various cell models. Patient-derived cell lines are very useful for identifying characteristic phenotypes and susceptibilities to anticancer drugs as well as molecularly targeted therapies for tumors. However, conventional 2-dimensional (2D) cell cultures have several drawbacks in terms of engraftment rate and phenotypic changes during culture. The organoid is a recently developed in vitro model with cultured cells that form a three-dimensional structure in the extracellular matrix. Organoids have the capacity to self-renew and can organize themselves to resemble the original organ or tumor in terms of both structure and function. Patient-derived cancer organoids are more suitable for the investigation of cancer biology and clinical medicine than conventional 2D cell lines or patient-derived xenografts. With recent advances in genetic analysis technology, the genetic information of various tumors has been clarified, and personalized medicine based on genetic information has become clinically available. Here, we have reviewed the recent advances in the development and application of patient-derived cancer organoids in cancer biology studies and personalized medicine. We have focused on the potential of organoids as a platform for the identification and development of novel targeted medicines for pancreatobiliary cancer, which is the most intractable cancer.

Development of patient derived organoids for cancer drug screening applications

Cancer is a disease characterised by abnormal cell growth that can invade or spread to other regions of the body. Organoids are three-dimensional ex vivo tissue cultures made from embryonic stem cells, induced pluripotent stem cells, progenitor cells or tissue that serve as a physiological model for cancer research. These are designed to recapitulate the in vivo properties of tumours. Importantly, effective recapitulation of the structure of tissues and function is believed to predict patient response, allowing for the creation of personalised therapy in a timely manner that may be used in the clinic. This Review discusses the pre-clinical model and different types of human organoids as models for the development of high throughput drug screening and also aims to highlight how organoids are shaping the future of cancer research.

Novel Ex Vivo Models of Epithelial Ovarian Cancer: The Future of Biomarker and Therapeutic Research

Epithelial ovarian cancer (EOC) is a heterogenous disease associated with variations in presentation, pathology and prognosis. Advanced EOC is typified by frequent relapse and a historical 5-year survival of less than 30% despite improvements in surgical and systemic treatment. The advent of next generation sequencing has led to notable advances in the field of personalised medicine for many cancer types. Success in achieving cure in advanced EOC has however been limited, although significant prolongation of survival has been demonstrated. Development of novel research platforms is therefore necessary to address the rapidly advancing field of early diagnostics and therapeutics, whilst also acknowledging the significant tumour heterogeneity associated with EOC. Within available tumour models, patient-derived organoids (PDO) and explant tumour slices have demonstrated particular promise as novel ex vivo systems to model different cancer types including ovarian cancer. PDOs are organ specific 3D tumour cultures that can accurately represent the histology and genomics of their native tumour, as well as offer the possibility as models for pharmaceutical drug testing platforms, offering timing advantages and potential use as prospective personalised models to guide clinical decision-making. Such applications could maximise the benefit of drug treatments to patients on an individual level whilst minimising use of less effective, yet toxic, therapies. PDOs are likely to play a greater role in both academic research and drug development in the future and have the potential to revolutionise future patient treatment and clinical trial pathways. Similarly, ex vivo tumour slices or explants have also shown recent renewed promise in their ability to provide a fast, specific, platform for drug testing that accurately represents in vivo tumour response. Tumour explants retain tissue architecture, and thus incorporate the majority of tumour microenvironment making them an attractive method to re-capitulate in vivo conditions, again with significant timing and personalisation of treatment advantages for patients. This review will discuss the current treatment landscape and research models for EOC, their development and new advances towards the discovery of novel biomarkers or combinational therapeutic strategies to increase treatment options for women with ovarian cancer.

Predicting Response to Anthracyclines in Ovarian Cancer

(1) Background: Anthracyclines are intriguing drugs, representing one of the cornerstones of both first and subsequent-lines of chemotherapy in ovarian cancer (OC). Their efficacy and mechanisms of action are related to the hot topics of OC clinical research, such as BRCA status and immunotherapy. Prediction of response to anthracyclines is challenging and no markers can predict certain therapeutic success. The current narrative review provides a summary of the clinical and biological mechanisms involved in the response to anthracyclines. (2) Methods: A MEDLINE search of the literature was performed, focusing on papers published in the last two decades. (3) Results and Conclusions: BRCA mutated tumors seem to show a higher response to anthracyclines compared to sporadic tumors and the severity of hand-foot syndrome and mucositis may be a predictive marker of PLD efficacy. CA125 can be a misleading marker of clinical response during treatment with anthracyclines, the response of which also appears to depend on OC histology. Immunochemistry, in particular HER-2 expression, could be of some help in predicting the response to such drugs, and high levels of mutated p53 appear after exposure to anthracyclines and impair their antitumor effect. Finally, organoids from OC are promising for drug testing and prediction of response to chemotherapy.

Stem cells technology as a platform for generating reproductive system organoids and treatment of infertility-related diseases

In recent years, stem cells have known as a helpful biological tool for the accurate diagnosis, treatment and recognition of diseases. Using stem cells as biomarkers have presented high potential in the early detection of many diseases. Another advancement in stem cell technology includes stem cell derived organoids model that could be a promising platform for diagnosis and modeling different diseases. Furthermore, therapeutic capabilities of stem cell therapy have increased hope in the face of different disability managements. All of these technologies are also widely used in reproductive related diseases especially in today's world that many couples encounter infertility problems. However, with the aid of numerous improvements in the treatment of infertility, over 80% of couples who dreamed of having children could now have children. Due to the fact that infertility has many negative effects on personal and social lives of young couples, many researchers have focused on the treatment of male and female reproductive system abnormalities with different types of stem cells, including embryonic stem cells, bone marrow mesenchymal stem cells (MSCs), and umbilical cord-derived MSCs. Also, design and formation of reproductive system organoids provide a fascinating window into disease modeling, drug screening, personalized therapy, and regeneration medicine. Utilizing these techniques to study, model and treat the infertility-related diseases has drawn attention of many scientists. This review explains different applications of stem cells in generating reproductive system organoids and stem cell-based therapies for male and female infertility related diseases treatment.

The Roles of Extracellular Vesicles and Organoid Models in Female Reproductive Physiology

Culture model systems that can recapitulate the anatomy and physiology of reproductive organs, such as three-dimensional (3D) organoid culture systems, limit the cost and welfare concerns associated with a research animal colony and provide alternative approaches to study specific processes in humans and animals. These 3D models facilitate a greater understanding of the physiological role of individual cell types and their interactions than can be accomplished with traditional monolayer culture systems. Furthermore, 3D culture systems allow for the examination of specific cellular, molecular, or hormonal interactions, without confounding factors that occur with in vivo models, and provide a powerful approach to study physiological and pathological reproductive conditions. The goal of this paper is to review and compare organoid culture systems to other in vitro cell culture models, currently used to study female reproductive physiology, with an emphasis on the role of extracellular vesicle interactions. The critical role of extracellular vesicles for intercellular communication in physiological processes, including reproduction, has been well documented, and an overview of the roles of extracellular vesicles in organoid systems will be provided. Finally, we will propose future directions for understanding the role of extracellular vesicles in normal and pathological conditions of reproductive organs, utilizing 3D organoid culture systems.

Human Endometrial Organoids: Recent Research Progress and Potential Applications

Since traditional two-dimensional (2D) cell culture cannot meet the demand of simulating physiological conditions in vivo, three-dimensional (3D) culture systems have been developed. To date, most of these systems have been applied for the culture of gastrointestinal and neural tissue. As for the female reproductive system, the culture of endometrial and oviductal tissues in Matrigel has also been performed, but there are still some problems that remain unsolved. This review highlights recent progress regarding endometrial organoids, focusing on the signal for organoid derivation and maintenance, the coculture of the epithelium and stroma, the drug screening using organoids from cancer patients, and provides a potential guideline for genome editing in endometrial organoids.

Three-Dimensional Modelling of Ovarian Cancer: From Cell Lines to Organoids for Discovery and Personalized Medicine

Ovarian cancer has the highest mortality of all of the gynecological malignancies. There are several distinct histotypes of this malignancy characterized by specific molecular events and clinical behavior. These histotypes have differing responses to platinum-based drugs that have been the mainstay of therapy for ovarian cancer for decades. For histotypes that initially respond to a chemotherapeutic regime of carboplatin and paclitaxel such as high-grade serous ovarian cancer, the development of chemoresistance is common and underpins incurable disease. Recent discoveries have led to the clinical use of PARP (poly ADP ribose polymerase) inhibitors for ovarian cancers defective in homologous recombination repair, as well as the anti-angiogenic bevacizumab. While predictive molecular testing involving identification of a genomic scar and/or the presence of germline or somatic BRCA1 or BRCA2 mutation are in clinical use to inform the likely success of a PARP inhibitor, no similar tests are available to identify women likely to respond to bevacizumab. Functional tests to predict patient response to any drug are, in fact, essentially absent from clinical care. New drugs are needed to treat ovarian cancer. In this review, we discuss applications to address the currently unmet need of developing physiologically relevant in vitro and ex vivo models of ovarian cancer for fundamental discovery science, and personalized medicine approaches. Traditional two-dimensional (2D) in vitro cell culture of ovarian cancer lacks critical cell-to-cell interactions afforded by culture in three-dimensions. Additionally, modelling interactions with the tumor microenvironment, including the surface of organs in the peritoneal cavity that support metastatic growth of ovarian cancer, will improve the power of these models. Being able to reliably grow primary tumoroid cultures of ovarian cancer will improve the ability to recapitulate tumor heterogeneity. Three-dimensional (3D) modelling systems, from cell lines to organoid or tumoroid cultures, represent enhanced starting points from which improved translational outcomes for women with ovarian cancer will emerge.

Organoids to model the endometrium: implantation and beyond

Despite advances in assisted reproductive techniques in the 4 decades since the first human birth after in vitro fertilisation, 1–2% of couples experience recurrent implantation failure, and some will never achieve a successful pregnancy even in the absence of a confirmed dysfunction. Furthermore, 1–2% of couples who do conceive, either naturally or with assistance, will experience recurrent early loss of karyotypically normal pregnancies. In both cases, embryo-endometrial interaction is a clear candidate for exploration. The impossibility of studying implantation processes within the human body has necessitated the use of animal models and cell culture approaches. Recent advances in 3-dimensional modelling techniques, namely the advent of organoids, present an exciting opportunity to elucidate the unanswerable within human reproduction. In this review, we will explore the ontogeny of implantation modelling and propose a roadmap to application and discovery.

Organoids and epithelial ovarian cancer - a future tool for personalized treatment decisions? (Review)

Epithelial ovarian cancer (EOC) is the 5th leading cause of cancer-associated death in females worldwide. Although 80% of cases respond well to initial treatment, >70% develop recurrent disease and become chemoresistant within the first two years. Therefore, there is a great need for predictive biomarkers to guide treatment. In the era of precision medicine, organoids are studied as a functional method to predict treatment response to oncological treatment. The overall purpose of the present systematic review was to uncover the current status of patient-derived organoids and their ability to perform drug screenings for EOC. A systematic search for studies investigating ovarian cancer and organoids was performed using PubMed and the Cochrane Library. A total of 10 studies fulfilled the inclusion criteria. The growth rates of organoids were described in six studies and varied between 29 and 90%. Only four studies included data on clinical outcomes and indicated a positive correlation between clinical response and drug screening results. Inter- and intratumoral heterogeneity was examined in seven studies. They all suggested that the organoids recapture the tumor heterogeneity. Only one study performed drug screenings on organoids obtained from different tumor sites and metastasis from the same patient with EOC and revealed a different response to at least one drug for all patients. In conclusion, organoids may provide a platform for predicting the clinical response to chemotherapy and gene-targeting therapy. However, the results are only exploratory and the number of published drug screening studies is minimal. Further research is required to prove that organoids are able to support the choice of oncological treatment in patients with EOC.

OUP accepted manuscript

BACKGROUND

To provide the optimal milieu for implantation and fetal development, the female reproductive system must orchestrate uterine dynamics with the appropriate hormones produced by the ovaries. Mature oocytes may be fertilized in the fallopian tubes, and the resulting zygote is transported toward the uterus, where it can implant and continue developing. The cervix acts as a physical barrier to protect the fetus throughout pregnancy, and the vagina acts as a birth canal (involving uterine and cervix mechanisms) and facilitates copulation. Fertility can be compromised by pathologies that affect any of these organs or processes, and therefore, being able to accurately model them or restore their function is of paramount importance in applied and translational research. However, innate differences in human and animal model reproductive tracts, and the static nature of 2D cell/tissue culture techniques, necessitate continued research and development of dynamic and more complex in vitro platforms, ex vivo approaches and in vivo therapies to study and support reproductive biology. To meet this need, bioengineering is propelling the research on female reproduction into a new dimension through a wide range of potential applications and preclinical models, and the burgeoning number and variety of studies makes for a rapidly changing state of the field.

OBJECTIVE AND RATIONALE

This review aims to summarize the mounting evidence on bioengineering strategies, platforms and therapies currently available and under development in the context of female reproductive medicine, in order to further understand female reproductive biology and provide new options for fertility restoration. Specifically, techniques used in, or for, the uterus (endometrium and myometrium), ovary, fallopian tubes, cervix and vagina will be discussed.

SEARCH METHODS

A systematic search of full-text articles available in PubMed and Embase databases was conducted to identify relevant studies published between January 2000 and September 2021. The search terms included: bioengineering, reproduction, artificial, biomaterial, microfluidic, bioprinting, organoid, hydrogel, scaffold, uterus, endometrium, ovary, fallopian tubes, oviduct, cervix, vagina, endometriosis, adenomyosis, uterine fibroids, chlamydia, Asherman’s syndrome, intrauterine adhesions, uterine polyps, polycystic ovary syndrome and primary ovarian insufficiency. Additional studies were identified by manually searching the references of the selected articles and of complementary reviews. Eligibility criteria included original, rigorous and accessible peer-reviewed work, published in English, on female reproductive bioengineering techniques in preclinical (in vitro/in vivo/ex vivo) and/or clinical testing phases.

OUTCOMES

Out of the 10 390 records identified, 312 studies were included for systematic review. Owing to inconsistencies in the study measurements and designs, the findings were assessed qualitatively rather than by meta-analysis. Hydrogels and scaffolds were commonly applied in various bioengineering-related studies of the female reproductive tract. Emerging technologies, such as organoids and bioprinting, offered personalized diagnoses and alternative treatment options, respectively. Promising microfluidic systems combining various bioengineering approaches have also shown translational value.

WIDER IMPLICATIONS

The complexity of the molecular, endocrine and tissue-level interactions regulating female reproduction present challenges for bioengineering approaches to replace female reproductive organs. However, interdisciplinary work is providing valuable insight into the physicochemical properties necessary for reproductive biological processes to occur. Defining the landscape of reproductive bioengineering technologies currently available and under development for women can provide alternative models for toxicology/drug testing, ex vivo fertility options, clinical therapies and a basis for future organ regeneration studies.

Does the "Devil" originate from the fallopian tubes?

Epithelial ovarian cancer (OC) is a heterogeneous disease and continues to be mostly diagnosed in advanced stages. The high lethality, the high rate of platinum-resistance, and the poor survival outcomes are the principal factors for categorizing OC among the most aggressive gynecological cancers. Only recently, a substantial progress has been made in our latest understanding of the origins of OC, particularly of high-grade serous histology. For a long time, the accumulation of genetic alterations in epithelial single layer cells of ovarian cysts caused by cyclic ovulations was considered as the most important driver and the long-standing dogma of ovarian tumorigenesis. Besides, the unique biological features and high histological heterogeneity of OC did not support this hypothesis. Indeed, various extra-ovarian cells of origin and multiple sites to each histotype were proposed, supported by cogent evidence from clinical cohorts and animal studies. In light of this enigma, this review was conducted to discuss the recent evidence supporting the revised origins of ovarian carcinoma histotypes with a particular focus on high-grade serous OC which may impact diagnostic and preventive approaches.

Patient-derived organoids as a preclinical platform for precision medicine in colorectal cancer

Patient‐derived organoids are being considered as models that can help guide personalized therapy through in vitro anticancer drug response evaluation. However, attempts to quantify in vitro drug responses in organoids and compare them with responses in matched patients remain inadequate. In this study, we investigated whether drug responses of organoids correlate with clinical responses of matched patients and disease progression of patients. Organoids were established from 54 patients with colorectal cancer who (except for one patient) did not receive any form of therapy before, and tumor organoids were assessed through whole‐exome sequencing. For comparisons of in vitro drug responses in matched patients, we developed an ‘organoid score’ based on the variable anticancer treatment responses observed in organoids. Very interestingly, a higher organoid score was significantly correlated with a lower tumor regression rate after the standard‐of‐care treatment in matched patients. Additionally, we confirmed that patients with a higher organoid score (≥ 2.5) had poorer progression‐free survival compared with those with a lower organoid score (< 2.5). Furthermore, to assess potential drug repurposing using an FDA‐approved drug library, ten tumor organoids derived from patients with disease progression were applied to a simulation platform. Taken together, organoids and organoid scores can facilitate the prediction of anticancer therapy efficacy, and they can be used as a simulation model to determine the next therapeutic options through drug screening. Organoids will be an attractive platform to enable the implementation of personalized therapy for colorectal cancer patients.

Modeling the Tumor Microenvironment of Ovarian Cancer: The Application of Self-Assembling Biomaterials

Ovarian cancer (OvCa) is one of the leading causes of gynecologic malignancies. Despite treatment with surgery and chemotherapy, OvCa disseminates and recurs frequently, reducing the survival rate for patients. There is an urgent need to develop more effective treatment options for women diagnosed with OvCa. The tumor microenvironment (TME) is a key driver of disease progression, metastasis and resistance to treatment. For this reason, 3D models have been designed to represent this specific niche and allow more realistic cell behaviors compared to conventional 2D approaches. In particular, self-assembling peptides represent a promising biomaterial platform to study tumor biology. They form nanofiber networks that resemble the architecture of the extracellular matrix and can be designed to display mechanical properties and biochemical motifs representative of the TME. In this review, we highlight the properties and benefits of emerging 3D platforms used to model the ovarian TME. We also outline the challenges associated with using these 3D systems and provide suggestions for future studies and developments. We conclude that our understanding of OvCa and advances in materials science will progress the engineering of novel 3D approaches, which will enable the development of more effective therapies.

The role of patient-derived ovarian cancer organoids in the study of PARP inhibitors sensitivity and resistance: from genomic analysis to functional testing

Epithelial ovarian cancer (EOC) harbors distinct genetic features such as homologous recombination repair (HRR) deficiency, and therefore may respond to poly ADP-ribose polymerase inhibitors (PARPi). Over the past few years, PARPi have been added to the standard of care for EOC patients in both front-line and recurrent settings. Next-generation sequencing (NGS) genomic analysis provides key information, allowing for the prediction of PARPi response in patients who are PARPi naïve. However, there are indeed some limitations in NGS analyses. A subset of patients can benefit from PARPi, despite the failed detection of the predictive biomarkers such as BRCA1/2 mutations or HRR deficiency. Moreover, in the recurrent setting, the sequencing of initial tumor does not allow for the detection of reversions or secondary mutations restoring proficient HRR and thus leading to PARPi resistance. Therefore, it becomes crucial to better screen patients who will likely benefit from PARPi treatment, especially those with prior receipt of maintenance PARPi therapy. Recently, patient-derived organoids (PDOs) have been regarded as a reliable preclinical platform with clonal heterogeneity and genetic features of original tumors. PDOs are found feasible for functional testing and interrogation of biomarkers for predicting response to PARPi in EOC. Hence, we review the strengths and limitations of various predictive biomarkers and highlight the role of patient-derived ovarian cancer organoids as functional assays in the study of PARPi response. It was found that a combination of NGS and functional assays using PDOs could enhance the efficient screening of EOC patients suitable for PARPi, thus prolonging their survival time.

In vitro modelling of the physiological and diseased female reproductive system

The maladies affecting the female reproductive tract (FRT) range from infections to endometriosis to carcinomas. In vitro models of the FRT play an increasingly important role in both basic and translational research, since the anatomy and physiology of the FRT of humans and other primates differ significantly from most of the commonly used animal models, including rodents. Using organoid culture to study the FRT has overcome the longstanding hurdle of maintaining epithelial phenotype in culture.  Both ECM-derived and engineered materials have proved critical for maintaining a physiological phenotype of FRT cells in vitro by providing the requisite 3D environment, ligands, and architecture. Advanced materials have also enabled the systematic study of factors contributing to the invasive metastatic processes. Meanwhile, microphysiological devices make it possible to incorporate physical signals such as flow and cyclic exposure to hormones. Going forward, advanced materials compatible with hormones and optimised to support FRT-derived cells' long-term growth, will play a key role in addressing the diverse array of FRT pathologies and lead to impactful new treatments that support the improvement of women's health. STATEMENT OF SIGNIFICANCE: The female reproductive system is a crucial component of the female anatomy. In addition to enabling reproduction, it has wide ranging influence on tissues throughout the body via endocrine signalling. This intrinsic role in regulating normal female biology makes it susceptible to a variety of female-specific diseases. However, the complexity and human-specific features of the reproductive system make it challenging to study. This has spurred the development of human-relevant in vitro models for helping to decipher the complex issues that can affect the reproductive system, including endometriosis, infection, and cancer. In this Review, we cover the current state of in vitro models for studying the female reproductive system, and the key role biomaterials play in enabling their development.

Reconstructing the tumor architecture into organoids

Cancer remains a leading health burden worldwide. One of the challenges hindering cancer therapy development is the substantial discrepancies between the existing cancer models and the tumor microenvironment (TME) of human patients. Constructing tumor organoids represents an emerging approach to recapitulate the pathophysiological features of the TME in vitro. Over the past decade, various approaches have been demonstrated to engineer tumor organoids as in vitro cancer models, such as incorporating multiple cellular populations, reconstructing biophysical and chemical traits, and even recapitulating structural features. In this review, we focus on engineering approaches for building tumor organoids, including biomaterial-based, microfabrication-assisted, and synthetic biology-facilitated strategies. Furthermore, we summarize the applications of engineered tumor organoids in basic cancer research, cancer drug discovery, and personalized medicine. We also discuss the challenges and future opportunities in using tumor organoids for broader applications.

Tumor spheroids and organoids as preclinical model systems

The generation of three-dimensional (3D) cancer models is a novel and fascinating development in the study of personalized medicine and tumor-specific drug delivery. In addition to the classical two-dimensional (2D) adherent cell culture models, 3D spheroid and organoid cancer models that mimic the microenvironment of cancer tissue are emerging as an important preclinical model system. 3D cancer models form, similar to cancer, multiple cell-cell and cell-extracellular matrix interactions and activate different cellular cascades/pathways, like proliferation, quiescence, senescence, and necrotic or apoptotic cell death. Further, it is possible to analyze genetic variations and mutations, the microenvironment of cell-cell interactions, and the uptake of therapeutics and nanoparticles in nanomedicine. Important is also the analysis of cancer stem cells (CSCs), which could play key roles in resistance to therapy and cancer recurrence. Tumor spheroids can be generated from one tumor-derived cell line or from co-culture of two or more cell lines. Tumor organoids can be derived from tumors or may be generated from CSCs that differentiate into multiple facets of cancerous tissue. Similarly, tumorspheres can be generated from a single CSC. By transplanting spheroids and organoids into immune-deficient mice, patient-derived xenografts can serve as a preclinical model to test therapeutics in vivo. Although the handling and analysis of 3D tumor spheroids and organoids is more complex, it will provide insights into various cancer processes that cannot be provided by 2D culture. Here a short overview of 3D tumor systems as preclinical models is provided.

Application of Ovarian Cancer Organoids in Precision Medicine: Key Challenges and Current Opportunities

Ovarian cancer (OC) is the leading cause of death among gynecologic malignances. Over the past decades, human-derived models have advanced from monolayer cell cultures to three-dimensional (3D) organoids that could faithfully recapitulate biological characteristics and tumor heterogeneity of primary tissues. As a complement of previous studies based on cell lines or xenografts, organoids provide a 3D platform for mutation–carcinogenesis modeling, high-throughput drug screening, genetic engineering, and biobanking, which might fulfill the gap between basic research and clinical practice. Stepwise, cutting-edge bioengineering techniques of organoid-on-a-chip and 3D bioprinting might converge current challenges and contribute to personalized therapy. We comprehensively reviewed the advantages, challenges, and translational potential of OC organoids. Undeniably, organoids represent an excellent near-physiological platform for OC, paving the way for precision medicine implementation. Future efforts will doubtlessly bring this innovative technique from bench to bedside.

Utilizing Patient-Derived Epithelial Ovarian Cancer Tumor Organoids to Predict Carboplatin Resistance

The development of patient-derived tumor organoids (TOs) from an epithelial ovarian cancer tumor obtained at the time of primary or interval debulking surgery has the potential to play an important role in precision medicine. Here, we utilized TOs to test front-line chemotherapy sensitivity and to investigate genomic drivers of carboplatin resistance. We developed six high-grade, serous epithelial ovarian cancer tumor organoid lines from tissue obtained during debulking surgery (two neoadjuvant-carboplatin-exposed and four chemo-naïve). Each organoid line was screened for sensitivity to carboplatin at four different doses (100, 10, 1, and 0.1 µM). Cell viability curves and resultant EC₅₀ values were determined. One organoid line, UK1254, was predicted to be resistant to carboplatin based on its EC₅₀ value (50.2 µM) being above clinically achievable Cmax. UK1254 had a significantly shorter PFS than the rest of the subjects (p = 0.0253) and was treated as a platinum-resistant recurrence. Subsequent gene expression analysis revealed extensively interconnected, differentially expressed pathways related to NF-kB, cellular differentiation (PRDM6 activation), and the linkage of B-cell receptor signaling to the PI3K-Akt signaling pathway (PI3KAP1 activation). This study demonstrates that patient-derived tumor organoids can be developed from patients at the time of primary or interval debulking surgery and may be used to predict clinical platinum sensitivity status or to investigate drivers of carboplatin resistance.

Redox modulation of vitagenes via plant polyphenols and vitamin D: Novel insights for chemoprevention and therapeutic interventions based on organoid technology

Polyphenols are chemopreventive through the induction of nuclear factor erythroid 2 related factor 2 (Nrf2)-mediated proteins and anti-inflammatory pathways. These pathways, encoding cytoprotective vitagenes, include heat shock proteins, such as heat shock protein 70 (Hsp70) and heme oxygenase-1 (HO-1), as well as glutathione redox system to protect against cancer initiation and progression. Phytochemicals exhibit biphasic dose responses on cancer cells, activating at low dose, signaling pathways resulting in upregulation of vitagenes, as in the case of the Nrf2 pathway upregulated by hydroxytyrosol (HT) or curcumin and NAD/NADH-sirtuin-1 activated by resveratrol. Here, the importance of vitagenes in redox stress response and autophagy mechanisms, as well as the potential use of dietary antioxidants in the prevention and treatment of multiple types of cancer are discussed. We also discuss the possible relationship between SARS-CoV-2, inflammation and cancer, exploiting innovative therapeutic approaches with HT-rich aqueous olive pulp extract (Hidrox®), a natural polyphenolic formulation, as well as the rationale of Vitamin D supplementation. Finally, we describe innovative approaches with organoids technology to study human carcinogenesis in preclinical models from basic cancer research to clinical practice, suggesting patient-derived organoids as an innovative tool to test drug toxicity and drive personalized therapy.

Patient-derived organoids reflect the genetic profile of endometrial tumors and predict patient prognosis

Background

A major hurdle in translational endometrial cancer (EC) research is the lack of robust preclinical models that capture both inter- and intra-tumor heterogeneity. This has hampered the development of new treatment strategies for people with EC.

Methods

EC organoids were derived from resected patient tumor tissue and expanded in a chemically defined medium. Established EC organoids were orthotopically implanted into female NSG mice. Patient tissue and corresponding models were characterized by morphological evaluation, biomarker and gene expression and by whole exome sequencing. A gene signature was defined and its prognostic value was assessed in multiple EC cohorts using Mantel-Cox (log-rank) test. Response to carboplatin and/or paclitaxel was measured in vitro and evaluated in vivo. Statistical difference between groups was calculated using paired t-test.

Results

We report EC organoids established from EC patient tissue, and orthotopic organoid-based patient-derived xenograft models (O-PDXs). The EC organoids and O-PDX models mimic the tissue architecture, protein biomarker expression and genetic profile of the original tissue. Organoids show heterogenous sensitivity to conventional chemotherapy, and drug response is reproduced in vivo. The relevance of these models is further supported by the identification of an organoid-derived prognostic gene signature. This signature is validated as prognostic both in our local patient cohorts and in the TCGA endometrial cancer cohort.

Conclusions

We establish robust model systems that capture both the diversity of endometrial tumors and intra-tumor heterogeneity. These models are highly relevant preclinical tools for the elucidation of the molecular pathogenesis of EC and identification of potential treatment strategies.

To study the biology of cancer and test new potential treatments, it is important to use models that mimic patients’ tumors. Such models have largely been lacking in endometrial cancer. We therefore aimed to developing miniature tumors, called “organoids”, directly from patient tumor tissue. Our organoids maintained the characteristics and genetic features of the tumors from which they were derived, would grow into endometrial tumors in mice, and exhibited patient-specific responses to chemotherapy drugs. In summary, we have developed models that will help us better understand the biology of endometrial tumors and can be used to potentially identify new effective drugs for endometrial cancer patients.

Berg et al. establish a panel of patient-derived endometrial cancer organoids and xenograft models. They show that their models recapitulate the genetic profile of the donor tumor and can be used for drug testing and development of a prognostic gene signature.

Organoids in Tissue Transplantation

Improvements in stem cell-based research and genetic modification tools enable stem cell-based tissue regeneration applications in clinical therapies. Although inadequate cell numbers in culture, invasive isolation procedures, and poor survival rates after transplantation remain as major challenges, cell-based therapies are useful tools for tissue regeneration.Organoids hold a great promise for tissue regeneration, organ and disease modeling, drug testing, development, and genetic profiling studies. Establishment of 3D cell culture systems eliminates the disadvantages of 2D models in terms of cell adaptation and tissue structure and function. Organoids possess the capacity to mimic the specific features of tissue architecture, cell-type composition, and the functionality of real organs while preserving the advantages of simplified and easily accessible cell culture models. Thus, organoid technology might emerge as an alternative to cell and tissue transplantation. Although transplantation of various organoids in animal models has been demonstrated, liöitations related to vascularized structure formation, cell viability and functionality remain as obstacles in organoid-based transplantation therapies. Clinical applications of organoid-based transplantations might be possible in the near future, when limitations related to cell viability and tissue integration are solved. In this review, the literature was analyzed and discussed to explore the current status of organoid-based transplantation studies.

Organ-on-a-chip technology for the study of the female reproductive system

Over the past decade, organs-on-a-chip and microphysiological systems have emerged as a disruptive in vitro technology for biopharmaceutical applications. By enabling new capabilities to engineer physiological living tissues and organ units in the precisely controlled environment of microfabricated devices, these systems offer great promise to advance the frontiers of basic and translational research in biomedical sciences. Here, we review an emerging body of interdisciplinary work directed towards harnessing the power of organ-on-a-chip technology for reproductive biology and medicine. The focus of this topical review is to provide an overview of recent progress in the development of microengineered female reproductive organ models with relevance to drug delivery and discovery. We introduce the engineering design of these advanced in vitro systems and examine their applications in the study of pregnancy, infertility, and reproductive diseases. We also present two case studies that use organ-on-a-chip design principles to model placental drug transport and hormonally regulated crosstalk between multiple female reproductive organs. Finally, we discuss challenges and opportunities for the advancement of reproductive organ-on-a-chip technology.

The ellagic acid metabolites urolithin A and B differentially affect growth, adhesion, motility, and invasion of endometriotic cells in vitro

STUDY QUESTION

What are the effects of plant-derived antioxidant compounds urolithin A (UA) and B (UB) on the growth and pathogenetic properties of an in vitro endometriosis model?

SUMMARY ANSWER

Both urolithins showed inhibitory effects on cell behavior related to the development of endometriosis by differentially affecting growth, adhesion, motility, and invasion of endometriotic cells in vitro.

WHAT IS KNOWN ALREADY

Endometriosis is one of the most common benign gynecological diseases in women of reproductive age and is defined by the presence of endometrial tissue outside the uterine cavity. As current pharmacological therapies are associated with side effects interfering with fertility, we aimed at finding alternative therapeutics using natural compounds that can be administered for prolonged periods with a favorable side effects profile.

STUDY DESIGN, SIZE, DURATION

In vitro cultures of primary endometriotic stromal cells from 6 patients subjected to laparoscopy for benign pathologies with histologically confirmed endometriosis; and immortalized endometrial stromal (St-T1b) and endometriotic epithelial cells (12Z) were utilized to assess the effects of UA and UB on endometriotic cell properties. Results were validated in three-dimensional (3D) in vitro co-culture spheroids of 12Z and primary endometriotic stroma cells of one patient, and organoids from 3 independent donors with endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The effects on cell growth were measured by non-radioactive colorimetric assay to measure cellular metabolic activity as an indicator of cell viability (MTT assay) and flow cytometric cell cycle assay on primary cultures, St-T1b, and 12Z. Apoptosis analyses, the impact on in vitro adhesion, migration, and invasion were evaluated in the cell lines. Moreover, Real-Time Quantitative Reverse Transcription polymerase chain reaction (RT-qPCR) assays were performed on primary cultures, St- T1b and 12Z to evaluate a plausible mechanistic contribution by factors related to proteolysis (matrix metalloproteinase 2, 3 and 9 -MMP2, MMP3, MMP9-, and tissue inhibitor of metalloproteinases -TIMP-1-), cytoskeletal regulators (Ras-related C3 botulinum toxin substrate 1 -RAC1-, Rho-associated coiled-coil containing protein kinase 2 -ROCK2-), and cell adhesion molecules (Syndecan 1 -SDC1-, Integrin alpha V-ITGAV-). Finally, the urolithins effects were evaluated on spheroids and organoids by formation, viability, and drug screen assays.

MAIN RESULTS AND THE ROLE OF CHANCE

40 µM UA and 20 µM UB produced a significant decrease in cell proliferation in the primary endometriotic cell cultures (P < 0.001 and P < 0.01, respectively) and in the St-T1b cell line (P < 0.001 and P < 0.05, respectively). In St-T1b, UA exhibited a mean half-maximum inhibitory concentration (IC50) of 39.88 µM, while UB exhibited a mean IC50 of 79.92 µM. Both 40 µM UA and 20 µM UB produced an increase in cells in the S phase of the cell cycle (P < 0.01 and P < 0.05, respectively). The same concentration of UA also increased the percentage of apoptotic ST-t1b cells (P < 0.05), while both urolithins decreased cell migration after 24 h (P < 0.001 both). Only the addition of 5 µM UB decreased the number of St-T1b adherent cells. TIMP-1 expression was upregulated in response to treating the cells with 40 µM UA (P < 0.05). Regarding the 12Z endometriotic cell line, only 40 µM UA decreased proliferation (P < 0.01); while both 40 µM UA and 20 µM UB produced an increase in cells in the G2/M phase (P < 0.05 and P < 0.01, respectively). In this cell line, UA exhibited a mean IC50 of 40.46 µM, while UB exhibited a mean IC50 of 54.79 µM. UB decreased cell migration (P < 0.05), and decreased the number of adherent cells (P < 0.05). Both 40 µM UA and 20 µM UB significantly decreased the cellular invasion of these cells; and several genes were altered when treating the cells with 40 µM UA and 10 µM UB. The expression of MMP2 was downregulated by UA (P < 0.001), and expression of MMP3 (UA P < 0.001 and UB P < 0.05) and MMP9 (P < 0.05, both) were downregulated by both urolithins. Moreover, UA significantly downregulated ROCK2 (P < 0.05), whereas UB treatment was associated with RAC1 downregulation (P < 0.05). Finally, the matrix adhesion receptors and signaling (co)receptors SDC1 and ITGAV were downregulated upon treatment with either UA or UB (P < 0.01 and P < 0.05, respectively in both cases). Regarding the effects of urolithins on 3D models, we have seen that they significantly decrease the viability of endometriosis spheroids (80 µM UA and UB: P < 0.05 both) as well as affecting their area (40 µM UA: P < 0.05, and 80 µM UA: P < 0.01) and integrity (40 µM UA and UB: P < 0.05, 80 µM UA and UB: P < 0.01). On the other hand, UA and UB significantly inhibited organoid development/outgrowth (40 and 80 µM UA: P < 0.0001 both; 40 µM UB: P < ns-0.05-0.001, and 80 µM UB: P < 0.01-0.001-0.001), and all organoid lines show urolithins sensitivity resulting in decreasing viability (UA exhibited a mean IC50 of 33.93 µM, while UB exhibited a mean IC50 of 52.60 µM).

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This study was performed on in vitro endometriosis models.

WIDER IMPLICATIONS OF THE FINDINGS

These in vitro results provide new insights into the pathogenetic pathways affected by these compounds and mark their use as a potential new therapeutic strategy for the treatment of endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded EU MSCA-RISE-2015 project MOMENDO (691058). The authors have no conflicts of interest to declare.

Organoids of the Female Reproductive Tract: Innovative Tools to Study Desired to Unwelcome Processes

The pelviperineal organs of the female reproductive tract form an essential cornerstone of human procreation. The system comprises the ectodermal external genitalia, the Müllerian upper-vaginal, cervical, endometrial and oviductal derivatives, and the endodermal ovaries. Each of these organs presents with a unique course of biological development as well as of malignant degeneration. For many decades, various preclinical in vitro models have been employed to study female reproductive organ (patho-)biology, however, facing important shortcomings of limited expandability, loss of representativeness and inadequate translatability to the clinic. The recent emergence of 3D organoid models has propelled the field forward by generating powerful research tools that in vitro replicate healthy as well as diseased human tissues and are amenable to state-of-the-art experimental interventions. Here, we in detail review organoid modeling of the different female reproductive organs from healthy and tumorigenic backgrounds, and project perspectives for both scientists and clinicians.

Organoids of the female reproductive tract

Healthy functioning of the female reproductive tract (FRT) depends on balanced and dynamic regulation by hormones during the menstrual cycle, pregnancy and childbirth. The mucosal epithelial lining of different regions of the FRT-ovaries, fallopian tubes, uterus, cervix and vagina-facilitates the selective transport of gametes and successful transfer of the zygote to the uterus where it implants and pregnancy takes place. It also prevents pathogen entry. Recent developments in three-dimensional (3D) organoid systems from the FRT now provide crucial experimental models that recapitulate the cellular heterogeneity and physiological, anatomical and functional properties of the organ in vitro. In this review, we summarise the state of the art on organoids generated from different regions of the FRT. We discuss the potential applications of these powerful in vitro models to study normal physiology, fertility, infections, diseases, drug discovery and personalised medicine.

The frontier of live tissue imaging across space and time

What you see is what you get-imaging techniques have long been essential for visualization and understanding of tissue development, homeostasis, and regeneration, which are driven by stem cell self-renewal and differentiation. Advances in molecular and tissue modeling techniques in the last decade are providing new imaging modalities to explore tissue heterogeneity and plasticity. Here we describe current state-of-the-art imaging modalities for tissue research at multiple scales, with a focus on explaining key tradeoffs such as spatial resolution, penetration depth, capture time/frequency, and moieties. We explore emerging tissue modeling and molecular tools that improve resolution, specificity, and throughput.

Patient-derived organoids and high grade serous ovarian cancer: from disease modeling to personalized medicine

BACKGROUND

High grade serous ovarian cancer (HGSOC) is among the deadliest human cancers and its prognosis remains extremely poor. Tumor heterogeneity and rapid acquisition of resistance to conventional chemotherapeutic approaches strongly contribute to poor outcome of patients. The clinical landscape of HGSOC has been radically transformed since the advent of targeted therapies in the last decade. Nevertheless, the lack of predictive biomarkers informing on the differential clinical benefit in select subgroups, and allowing patient-centric approaches, currently limits the efficacy of these novel therapies. Thus, rational selection of the best possible treatment for each patient represents a clinical priority in order to improve outcome, while limiting undesirable effects.

MAIN BODY

In this review, we describe the state of the art and the unmet needs in HGSOC management, illustrate the treatment options that are available and the biomarkers that are currently employed to orient clinical decisions. We also describe the ongoing clinical trials that are testing new therapeutic approaches for HGSOC. Next, we introduce the organoid technology as a promising, expanding strategy to study cancer and to develop personalized therapeutic approaches. In particular, we discuss recent studies that have characterized the translational potential of Patient's Derived Organoids (PDOs) to inform on drug sensitivity of HGSOC patients.

CONCLUSIONS

PDOs can predict the response of patients to treatments and may therefore guide therapeutic decisions. Although preliminary results appear encouraging, organoids still need to be generated and expanded efficiently to enable drug screening in a clinically meaningful time window. A new generation of clinical trials based on the organoid technology should guarantee tailored approaches to ovarian cancer management, as it is now clear that the one-size-fits-all approach cannot lead to efficient and meaningful therapeutic advancements.

Protocol for establishing organoids from human ovarian cancer biopsies

Ovarian cancer (OC) is the most lethal gynecological cancer. Faithful research models are indispensable to the progression of understanding OC etiology and therapy. Here, we provide a detailed protocol for establishing organoid cultures from patient OC biopsies. The organoids reproduce primary tumor- and patient-specific characteristics including phenotypic properties and genomic aberrations and exhibit patient-dependent responsiveness to drugs. OC-derived organoids provide powerful tools to gain deep insight into the cancer’s pathobiology and to screen patient-tumor drug sensitivity to progress toward personalized medicine.

For complete details on the use and execution of this protocol, please refer to Maenhoudt et al. (2020).

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Detailed protocol for the establishment and expansion of ovarian cancer organoids

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Ovarian cancer organoids recapitulate key characteristics of the primary tumor

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Personalized drug screening assays can be performed using ovarian cancer organoids

Establishment of in vitro 3D spheroid cell cultivation from human gynecologic cancer tissues

Advanced-stage gynecologic cancer remains a life-threatening disease. Here, we present a protocol for establishment of stable in vitro 3D spheroid cells derived from human uterine endometrial and ovarian cancer tissues. The tumor-derived spheroid cells have cancer stem cell-related characteristics, including tumorigenesis, and can be used for biological and biochemical analyses and drug efficacy assays. Because these cells possess the biological characteristics of original human tumors, spheroid cells and spheroid-derived xenografts will have applications in personalized medicine in the future.

For complete details on the use and execution of this protocol, please refer to Ishiguro et al. (2016) and Mori et al. (2019).

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Protocol for establishing spheroid cells from human gynecologic cancer tissue

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A procedure to culture spheroids with cancer stem cell-related characteristics

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Tumor-derived spheroids possess original human tumors’ biological characteristics

Organoid and Spheroid Tumor Models: Techniques and Applications

Simple Summary

Cell cultures can be carried out in three dimensions (3D). Organoids and spheroids are different 3D cell culture models that can be cultured with different techniques. These 3D cell culture units established from a patient tumor have several similarities to the original tumor tissue and possess several advantages in conducting basic and clinical cancer research. Organoids prepared from a patient tissue can be preserved in a living biobank. Testing chemo-, radio- and immuno-therapies on these organoids has the potential to predict the patient responses and these models have incredible promise for personalized medicine. This review presents different organoid models, the techniques to prepare them and recent advances in their applications.

Abstract

Techniques to develop three-dimensional cell culture models are rapidly expanding to bridge the gap between conventional cell culture and animal models. Organoid and spheroid cultures have distinct and overlapping purposes and differ in cellular sources and protocol for establishment. Spheroids are of lower complexity structurally but are simple and popular models for drug screening. Organoids histologically and genetically resemble the original tumor from which they were derived. Ease of generation, ability for long-term culture and cryopreservation make organoids suitable for a wide range of applications. Organoids-on-chip models combine organoid methods with powerful designing and fabrication of micro-chip technology. Organoid-chip models can emulate the dynamic microenvironment of tumor pathophysiology as well as tissue–tissue interactions. In this review, we outline different tumor spheroid and organoid models and techniques to establish them. We also discuss the recent advances and applications of tumor organoids with an emphasis on tumor modeling, drug screening, personalized medicine and immunotherapy.

Historical evolution of spheroids and organoids, and possibilities of use in life sciences and medicine

BACKGROUND

An impressive percentage of biomedical advances were achieved through animal research and cell culture investigations. For drug testing and disease researches, both animal models and preclinical trials with cell cultures are extremely important, but present some limitations, such as ethical concern and inability of representing complex tissues and organs. 3D cell cultures arise providing a more realistic in vitro representation of tissues and organs. Environment and cell type in 3D cultures can represent in vivo conditions and thus provide accurate data on cell-to-cell interactions, and cultivation techniques are based on a scaffold, usually hydrogel or another polymeric material, or without scaffold, such as suspended microplates, magnetic levitation, and microplates for spheroids with ultra-low fixation coating.

PURPOSE AND SCOPE

This review aims at presenting an updated summary of the most common 3D cell culture models available, as well as a historical background of their establishment and possible applications.

SUMMARY

Even though 3D culturing is incapable of replacing other current research types, they will continue to substitute some unnecessary animal experimentation, as well as complement monolayer cultures.

CONCLUSION

In this aspect, 3D culture emerges as a valuable alternative to the investigation of functional, biochemical, and molecular aspects of human pathologies.

The organoid: A research model for ovarian cancer

Epithelial ovarian cancer (EOC) is a heterogeneous disease with a variety of distinct clinical and molecular characteristics. The currently available and common research models for EOC include tumor cell lines and patient-derived xenografts. However, these models have certain shortcomings: establishing a cell line is time-consuming, loss of genetic traits after long-term culture is a possibility, and investment is required in terms of animal care facilities. Therefore, better research models are required. Organoid technology was originally developed from colorectal cancer. Tumor organoid is a three-dimensional culture system and can help accurately recapture the tumor phenotype from the original tumor. Tumor organoid systems can overcome the above-mentioned shortcomings of the currently available research models. The organoid model can be used for culturing ovarian cancer subtypes, screening drugs, assessing genomes, and establishing biobanks. However, the currently available organoid models can only culture one type of cells, epithelial cells. Therefore, an organoid-on-a-chip device can be developed in the future to provide a microenvironment for cell–cell, cell–matrix, and cell–media interactions. Thus, organoid models can be used in ovarian cancer research and can generate a simulated in vivo system, enabling studies on the heterogeneity of ovarian cancer.

Exploring the Potential of Drug Response Assays for Precision Medicine in Ovarian Cancer

One of the major challenges in the treatment of cancer are differential responses of patients to existing standard of care anti-cancer drugs. These differential responses may, in part, be due to a diverse range of genomic, epigenomic, proteomic, and metabolic alterations among individuals suffering from the same type of cancer. Precision medicine is an emerging approach in cancer therapeutics that takes into account specific molecular alterations, environmental factors as well as lifestyle of individual patients. This approach allows clinicians and researchers to select or predict treatments that would most likely benefit the patient based on their individual tumor characteristics. One class of precision medicine tools are predictive, in vitro drug-response assays designed to test the sensitivity of patient tumor cells to existing or novel therapies. These assays have the potential to rapidly identify the most effective treatments for cancer patients and thus hold great promise in the field of precision medicine. In this review, we have highlighted several drug-response assays developed in ovarian cancer and discussed the current challenges and future prospects of these assays in the clinical management of this disease.

From 2D to 3D Cancer Cell Models-The Enigmas of Drug Delivery Research

Over the past decades, research has made impressive breakthroughs towards drug delivery systems, resulting in a wide range of multifunctional engineered nanoparticles with biomedical applications such as cancer therapy. Despite these significant advances, well-designed nanoparticles rarely reach the clinical stage. Promising results obtained in standard 2D cell culture systems often turn into disappointing outcomes in in vivo models. Although the overall majority of in vitro nanoparticle research is still performed on 2D monolayer cultures, more and more researchers started acknowledging the importance of using 3D cell culture systems, as better models for mimicking the in vivo tumor physiology. In this review, we provide a comprehensive overview of the 3D cancer cell models currently available. We highlight their potential as a platform for drug delivery studies and pinpoint the challenges associated with their use. We discuss in which way each 3D model mimics the in vivo tumor physiology, how they can or have been used in nanomedicine research and to what extent the results obtained so far affect the progress of nanomedicine development. It is of note that the global scientific output associated with 3D models is limited, showing that the use of these systems in nanomedicine investigation is still highly challenging.

Promising Applications of Tumor Spheroids and Organoids for Personalized Medicine

One of the promising directions in personalized medicine is the use of three-dimensional (3D) tumor models such as spheroids and organoids. Spheroids and organoids are three-dimensional cultures of tumor cells that can be obtained from patient tissue and, using high-throughput personalized medicine methods, provide a suitable therapy for that patient. These 3D models can be obtained from most types of tumors, which provides opportunities for the creation of biobanks with appropriate patient materials that can be used to screen drugs and facilitate the development of therapeutic agents. It should be noted that the use of spheroids and organoids would expand the understanding of tumor biology and its microenvironment, help develop new in vitro platforms for drug testing and create new therapeutic strategies. In this review, we discuss 3D tumor spheroid and organoid models, their advantages and disadvantages, and evaluate their promising use in personalized medicine.