Patient-derived xenograft models capture genomic heterogeneity in endometrial cancer

Establishment and characterization of multiple patient-derived organoids from a case of advanced endometrial cancer

Patient-derived organoids (PDOs) retain the original tumor's characteristics to a large degree and allow direct evaluation of the drug sensitivity, thereby emerging as a valuable resource for both basic and preclinical researches. Whereas most past studies stereotypically adopted a single PDO as an avatar of the patient, it remains to be investigated whether this assumption can be justified even for the tumor with spatial diversity. To address this issue, we established and characterized multiple PDOs originating from various sites of a patient with advanced uterine carcinosarcoma (UCS). Specifically, cancer cells were separately sampled from three sites; resected UCS tumor tissue, the peritoneal lavage fluid, and an intra-uterine brushing of the tumor. The three derived PDOs were morphologically undistinguishable, displaying typical carcinoma organoids-like appearance, but two of them proliferated at a faster rate. The primary tumor harbored mutations in TP53 and STK11 along with amplifications in CCNE1, ERBB2, and KRAS. These two mutations and the CCNE1 amplification were detected in all PDOs, while either KRAS or ERBB2 amplification was selectively observed in each PDO in a mutually exclusive manner. Observed intra-tumor heterogeneity in HER2 expression was differentially reproduced in the PDOs, which mirrored each PDO's sensitivity to HER2 inhibitors. Inter-PDO heterogeneity was also evident in sensitivity to standard cytotoxic agents. Lastly, a drug screening identified four candidate reagents commonly effective to all PDOs. Collectively, we showed that multiple PDOs could help reproduce the spatial diversity of a tumor and serve as a valuable resource in UCS research in many respects.

Consistency between Primary Uterine Corpus Malignancies and Their Corresponding Patient-Derived Xenograft Models

Patient-derived xenograft (PDX) models retain the characteristics of tumors and are useful tools for personalized therapy and translational research. In this study, we aimed to establish PDX models for uterine corpus malignancies (UC-PDX) and analyze their similarities. Tissue fragments obtained from 92 patients with uterine corpus malignancies were transplanted subcutaneously into immunodeficient mice. Histological and immunohistochemical analyses were performed to compare tumors of patients with PDX tumors. DNA and RNA sequencing were performed to validate the genetic profile. Furthermore, the RNA in extracellular vesicles (EVs) extracted from primary and PDX tumors was analyzed. Among the 92 cases, 52 UC-PDX models were established, with a success rate of 56.5%. The success rate depended on tumor histology and staging. The pathological and immunohistochemical features of primary and PDX tumors were similar. DNA sequencing revealed similarities in gene mutations between the primary and PDX tumors. RNA sequencing showed similarities in gene expressions between primary and PDX tumors. Furthermore, the RNA profiles of the EVs obtained from primary and PDX tumors were similar. As UC-PDX retained the pathological and immunohistochemical features and gene profiles of primary tumors, they may provide a platform for developing personalized medicine and translational research.

Development and Expansion of Patient-Derived Xenografts for Endometrial Cancer

Patient-Derived Xenografts (PDXs) are established by implanting a fragment of a patient tumor into rodents either subcutaneously or orthotopically. PDX models faithfully recapitulate the histologic and molecular profile of the donor patient's cancer and are regarded as authentic preclinical models for drug testing, understanding of tumor biology and biomarker discovery. This Chapter describes the detailed method for establishing robust PDXs for endometrial cancer and provide important notes for users of the protocol to consider during PDXs development.

Targeting DNA Damage Repair and Immune Checkpoint Proteins for Optimizing the Treatment of Endometrial Cancer

The dependence of cancer cells on the DNA damage response (DDR) pathway for the repair of endogenous- or exogenous-factor-induced DNA damage has been extensively studied in various cancer types, including endometrial cancer (EC). Targeting one or more DNA damage repair protein with small molecules has shown encouraging treatment efficacy in preclinical and clinical models. However, the genes coding for DDR factors are rarely mutated in EC, limiting the utility of DDR inhibitors in this disease. In the current review, we recapitulate the functional role of the DNA repair system in the development and progression of cancer. Importantly, we discuss strategies that target DDR proteins, including PARP, CHK1 and WEE1, as monotherapies or in combination with cytotoxic agents in the treatment of EC and highlight the compounds currently being evaluated for their efficacy in EC in clinic. Recent studies indicate that the application of DNA damage agents in cancer cells leads to the activation of innate and adaptive immune responses; targeting immune checkpoint proteins could overcome the immune suppressive environment in tumors. We further summarize recently revolutionized immunotherapies that have been completed or are now being evaluated for their efficacy in advanced EC and propose future directions for the development of DDR-based cancer therapeutics in the treatment of EC.

Organoids: approaches and utility in cancer research

ABSTRACT

Organoids are three-dimensional cellular structures with self-organizing and self-differentiation capacities. They faithfully recapitulate structures and functions of in vivo organs as represented by functionality and microstructural definitions. Heterogeneity in in vitro disease modeling is one of the main reasons for anti-cancer therapy failures. Establishing a powerful model to represent tumor heterogeneity is crucial for elucidating tumor biology and developing effective therapeutic strategies. Tumor organoids can retain the original tumor heterogeneity and are commonly used to mimic the cancer microenvironment when co-cultured with fibroblasts and immune cells; therefore, considerable effort has been made recently to promote the use of this new technology from basic research to clinical studies in tumors. In combination with gene editing technology and microfluidic chip systems, engineered tumor organoids show promising abilities to recapitulate tumorigenesis and metastasis. In many studies, the responses of tumor organoids to various drugs have shown a positive correlation with patient responses. Owing to these consistent responses and personalized characteristics with patient data, tumor organoids show excellent potential for preclinical research. Here, we summarize the properties of different tumor models and review their current state and progress in tumor organoids. We further discuss the substantial challenges and prospects in the rapidly developing tumor organoid field.

Gynecologic and Breast Cancers: What's New in Chemoresistance and Chemosensitivity Tests?

Gynecological and breast cancers affect women's health worldwide. Although chemotherapy is one of the principal treatments for cancer, it also has limitations owing to toxicity and tumor resistance to the drugs used. Thus, individualized treatment based on personal tumor characteristics is essential for improving therapeutic outcomes and patient survival. Chemoresistance and chemosensitivity tests can be useful for predicting tumor response and guiding chemotherapy choices. This methodology has already been applied to breast, ovarian, cervical, and endometrial cancers, identifying successfully which drugs cause resistance and sensitivity responses for each individual person, influencing their progression-free survival and overall response. In addition, more recent techniques, such as organoids and patient-derived xenografts, can also recapitulate patients' tumor characteristics and contribute to chemo response evaluation. Therefore, this review compiles information on chemoresistance and chemosensitivity tests performed in gynecologic and breast cancers and their main results for women's health improvement.

Multi-omic features of oesophageal adenocarcinoma in patients treated with preoperative neoadjuvant therapy

Oesophageal adenocarcinoma is a poor prognosis cancer and the molecular features underpinning response to treatment remain unclear. We investigate whole genome, transcriptomic and methylation data from 115 oesophageal adenocarcinoma patients mostly from the DOCTOR phase II clinical trial (Australian New Zealand Clinical Trials Registry-ACTRN12609000665235), with exploratory analysis pre-specified in the study protocol of the trial. We report genomic features associated with poorer overall survival, such as the APOBEC mutational and RS3-like rearrangement signatures. We also show that positron emission tomography non-responders have more sub-clonal genomic copy number alterations. Transcriptomic analysis categorises patients into four immune clusters correlated with survival. The immune suppressed cluster is associated with worse survival, enriched with myeloid-derived cells, and an epithelial-mesenchymal transition signature. The immune hot cluster is associated with better survival, enriched with lymphocytes, myeloid-derived cells, and an immune signature including CCL5, CD8A, and NKG7. The immune clusters highlight patients who may respond to immunotherapy and thus may guide future clinical trials.

Alteration in molecular properties during establishment and passaging of endometrial carcinoma patient-derived xenografts

Patient-derived xenograft (PDX) tumor models are known to maintain the genomic and phenotypic profiles, including the histopathological structures, of the parental tumors. On the other hand, unique enrichment of single-nucleotide variants or copy number aberrations has been reported in several types of tumors. However, an understanding of endometrial carcinoma PDXs is limited. The purpose of the present study was to clarify the presence or absence of the molecular properties of endometrial carcinomas in PDXs passaged up to eight times. Established PDXs of endometrioid carcinomas maintained their histopathological characteristics, but those of carcinosarcomas predominantly consisted of sarcomatous components when compared to the parental tumors. Alterations in the proportion of cells with positive/negative immunohistochemical staining for estrogen receptor, PTEN, PAX8, and PAX2 were observed, whereas the proportions of cells with AE1/AE3, TP53, ARID1A, PMS2, and MSH6 staining were unchanged. Variants of cancer-associated genes were compared between PDXs and parental tumors. Mutations in POLE and a frameshift deletion in BRCA1 were observed in the parental tumor tissue in each of the six cases, and additional genomic alterations, which were not apparently related to histopathological and immunohistochemical alterations, were found in the PDXs of these cases. The genomic and phenotypic alterations observed between endometrial carcinoma PDXs and parental tumors were partly associated with endometrial cancer-specific characteristics related to cellular differentiation and gene mutations.

Targeting PARP for the optimal immunotherapy efficiency in gynecologic malignancies

Gynecologic cancer, which includes ovarian, cervical, endometrial, vulvar, and vaginal cancer, is a major health concern for women all over the world. Despite the availability of various treatment options, many patients eventually progress to advanced stages and face high mortality rates. PARPi (poly (ADP-ribose) polymerase inhibitor) and immune checkpoint inhibitor (ICI) have both shown significant efficacy in the treatment of advanced and metastatic gynecologic cancer. However, both treatments have limitations, including inevitable resistance and a narrow therapeutic window, making PARPi and ICI combination therapy a promising approach to treating gynecologic malignancies. Preclinical and clinical trials have looked into the combination therapy of PARPi and ICI. PARPi improves ICI efficacy by inducing DNA damage and increasing tumor immunogenicity, resulting in a stronger immune response against cancer cells. ICI, conversly, can increase PARPi sensitivity by priming and activating immune cells, consequently prompting immune cytotoxic effect. Several clinical trials in gynecologic cancer patients have investigated the combination therapy of PARPi and ICI. When compared to monotherapy, the combination of PARPi and ICI increased progression-free survival and overall survival in ovarian cancer patients. The combination therapy has also been studied in other types of gynecologic cancer, including endometrial and cervical cancer, with promising results. Finally, the combination therapeutic strategy of PARPi and ICI is a promising approach in the treatment of gynecologic cancer, particularly advanced and metastatic stages. Preclinical studies and clinical trials have demonstrated the safety and efficacy of this combination therapy in improving patient outcomes and quality of life.

Patient-derived xenograft models in cancer therapy: technologies and applications

Patient-derived xenograft (PDX) models, in which tumor tissues from patients are implanted into immunocompromised or humanized mice, have shown superiority in recapitulating the characteristics of cancer, such as the spatial structure of cancer and the intratumor heterogeneity of cancer. Moreover, PDX models retain the genomic features of patients across different stages, subtypes, and diversified treatment backgrounds. Optimized PDX engraftment procedures and modern technologies such as multi-omics and deep learning have enabled a more comprehensive depiction of the PDX molecular landscape and boosted the utilization of PDX models. These irreplaceable advantages make PDX models an ideal choice in cancer treatment studies, such as preclinical trials of novel drugs, validating novel drug combinations, screening drug-sensitive patients, and exploring drug resistance mechanisms. In this review, we gave an overview of the history of PDX models and the process of PDX model establishment. Subsequently, the review presents the strengths and weaknesses of PDX models and highlights the integration of novel technologies in PDX model research. Finally, we delineated the broad application of PDX models in chemotherapy, targeted therapy, immunotherapy, and other novel therapies.

Strategies for modelling endometrial diseases

Each month during a woman's reproductive years, the endometrium undergoes vast changes to prepare for a potential pregnancy. Diseases of the endometrium arise for numerous reasons, many of which remain unknown. These endometrial diseases, including endometriosis, adenomyosis, endometrial cancer and Asherman syndrome, affect many women, with an overall lack of efficient or permanent treatment solutions. The challenge lies in understanding the complexity of the endometrium and the extensive changes, orchestrated by ovarian hormones, that occur in multiple cell types over the period of the menstrual cycle. Appropriate model systems that closely mimic the architecture and function of the endometrium and its diseases are needed. The emergence of organoid technology using human cells is enabling a revolution in modelling the endometrium in vitro. The goal of this Review is to provide a focused reference for new models to study the diseases of the endometrium. We provide perspectives on the power of new and emerging models, from organoids to microfluidics, which have opened up a new frontier for studying endometrial diseases.

Generation and Integrated Analysis of Advanced Patient-Derived Orthoxenograft Models (PDOX) for the Rational Assessment of Targeted Therapies in Endometrial Cancer

Clinical management of endometrial cancer (EC) is handicapped by the limited availability of second line treatments and bona fide molecular biomarkers to predict recurrence. These limitations have hampered the treatment of these patients, whose survival rates have not improved over the last four decades. The advent of coordinated studies such as The Cancer Genome Atlas Uterine Corpus Endometrial Carcinoma (TCGA_UCEC) has partially solved this issue, but the lack of proper experimental systems still represents a bottleneck that precludes translational studies from successful clinical testing in EC patients. Within this context, the first study reporting the generation of a collection of endometrioid-EC-patient-derived orthoxenograft (PDOX) mouse models is presented that is believed to overcome these experimental constraints and pave the way toward state-of-the-art precision medicine in EC. The collection of primary tumors and derived PDOXs is characterized through an integrative approach based on transcriptomics, mutational profiles, and morphological analysis; and it is demonstrated that EC tumors engrafted in the mouse uterus retain the main molecular and morphological features from analogous tumor donors. Finally, the molecular properties of these tumors are harnessed to assess the therapeutic potential of trastuzumab, a human epidermal growth factor receptor 2 (HER2) inhibitor with growing interest in EC, using patient-derived organotypic multicellular tumor spheroids and in vivo experiments.

Validation of a Patient-Derived Xenograft Model for Cervical Cancer Based on Genomic and Phenotypic Characterization

Simple Summary

The rate of total tumor engraftment of patient-derived xenografts is 50% in cervical cancer. These cancers retain their histopathological characteristics. The gene mutations and expression patterns associated with carcinogenesis and infiltration and the expression levels of genes in extracellular vesicles released from the tumors are similar between patient-derived xenograft models and primary tumors. Patient-derived xenograft models of cervical cancer could be potentially useful tools for translational research.

Abstract

Patient-derived xenograft (PDX) models are useful tools for preclinical drug evaluation, biomarker identification, and personalized medicine strategies, and can be developed by the heterotopic or orthotopic grafting of surgically resected tumors into immunodeficient mice. We report the PDX models of cervical cancer and demonstrate the similarities among original and different generations of PDX tumors. Fresh tumor tissues collected from 22 patients with primary cervical cancer were engrafted subcutaneously into NOD.CB17-PrkdcSCID/J mice. Histological and immunohistochemical analyses were performed to compare primary and different generations of PDX tumors. DNA and RNA sequencing were performed to verify the similarity between the genetic profiles of primary and PDX tumors. Total RNA in extracellular vesicles (EVs) released from primary and PDX tumors was also quantified to evaluate gene expression. The total tumor engraftment rate was 50%. Histologically, no major differences were observed between the original and PDX tumors. Most of the gene mutations and expression patterns related to carcinogenesis and infiltration were similar between the primary tumor and xenograft. Most genes associated with carcinogenesis and infiltration showed similar expression levels in the primary tumor and xenograft EVs. Therefore, compared with primary tumors, PDX models could be potentially more useful for translational research.

Genomic Validation of Endometrial Cancer Patient-Derived Xenograft Models as a Preclinical Tool

Endometrial cancer (EC) is the second most frequent gynecological cancer worldwide. Although improvements in EC classification have enabled an accurate establishment of disease prognosis, women with a high-risk or recurrent EC face a dramatic situation due to limited further treatment options. Therefore, new strategies that closely mimic the disease are required to maximize drug development success. Patient-derived xenografts (PDXs) are widely recognized as a physiologically relevant preclinical model. Hence, we propose to molecularly and histologically validate EC PDX models. To reveal the molecular landscape of PDXs generated from 13 EC patients, we performed histological characterization and whole-exome sequencing analysis of tumor samples. We assessed the similarity between PDXs and their corresponding patient's tumor and, additionally, to an extended cohort of EC patients obtained from The Cancer Genome Atlas (TCGA). Finally, we performed functional enrichment analysis to reveal differences in molecular pathway activation in PDX models. We demonstrated that the PDX models had a well-defined and differentiated molecular profile that matched the genomic profile described by the TCGA for each EC subtype. Thus, we validated EC PDX's potential to reliably recapitulate the majority of histologic and molecular EC features. This work highlights the importance of a thorough characterization of preclinical models for the improvement of the success rate of drug-screening assays for personalized medicine.

Endometrial Cancer Patient-Derived Xenograft Models: A Systematic Review

Background: Because patient-derived xenograft (PDX) models resemble the original tumors, they can be used as platforms to find target agents for precision medicine and to study characteristics of tumor biology such as clonal evolution and microenvironment interactions. The aim of this review was to identify articles on endometrial cancer PDXs (EC-PDXs) and verify the methodology and outcomes. Methods: We used PubMed to research and identify articles on EC-PDX. The data were analyzed descriptively. Results: Post literature review, eight studies were selected for the systematic review. Eighty-five EC-PDXs were established from 173 patients with EC, with a total success rate of 49.1%. A 1–10 mm³ fragment was usually implanted. Fresh-fragment implantation had higher success rates than using overnight-stored or frozen fragments. Primary tumors were successfully established with subcutaneous implantation, but metastasis rarely occurred; orthotopic implantation via minced tumor cell injection was better for metastatic models. The success rate did not correspond to immunodeficiency grades, and PDXs using nude mice reduced costs. The tumor growth period ranged from 2 weeks to 13 months. Similar characteristics were observed between primary tumors and PDXs, including pathological findings, gene mutations, and gene expression. Conclusion: EC-PDXs are promising tools for translational research because they closely resemble the features of tumors in patients and retain molecular and histological features of the disease.