Radiation sensitivity assay with a panel of patient-derived spheroids of small cell carcinoma of the cervix

Advancements in the Understanding of Small-Cell Neuroendocrine Cervical Cancer: Where We Stand and What Lies Ahead

Small-cell neuroendocrine cervical carcinoma (SCNCC) is a rare yet aggressive gynecological malignancy associated with dismal clinical outcomes. Its rarity has led to a limited number of retrospective studies and an absence of prospective research, posing significant challenges for evidence-based treatment approaches. As a result, most gynecologic oncology centers have limited experience with this tumor, emphasizing the urgent need for a comprehensive review and summary. This article systematically reviews the pathogenesis, immunohistochemical and molecular characteristics, prognostic factors, and clinical management of gynecologic SCNCC. We specifically focused on reviewing the distinct genomic characteristics of SCNCC identified via next-generation sequencing technologies, including loss of heterozygosity (LOH), somatic mutations, structural variations (SVs), and microRNA alterations. The identification of these actionable genomic events offers promise for discovering new molecular targets for drug development and enhancing therapeutic outcomes. Additionally, we delve deeper into key clinical challenges, such as determining the optimal treatment modality between chemoradiation and surgery for International Federation of Gynecology and Obstetrics (FIGO) stage I phase patients within a precision stratification framework, as well as the role of targeted therapy within the homologous recombination (HR) pathway, immune checkpoint inhibitors (ICIs), and prophylactic cranial irradiation (PCI) in the management of SCNCC. Finally, we anticipate the utilization of multiple SCNCC models, including cancer tissue-originated spheroid (CTOS) lines and patient-derived xenografts (PDXs), to decipher driver events and develop individualized therapeutic strategies for clinical application.

Clonal Origin and Lineage Ambiguity in Mixed Neuroendocrine Carcinoma of the Uterine Cervix

Small-cell neuroendocrine carcinoma (SCNEC) of the cervix is a rare disease characterized by a high incidence of mixed tumors with other types of cancer. The mechanism underlying this mixed phenotype is not well understood. This study established a panel of organoid lines from patients with SCNEC of the cervix and ultimately focused on one line, which retained a mixed tumor phenotype, both in vitro and in vivo. Histologically, both organoids and xenograft tumors showed distinct differentiation into either SCNEC or adenocarcinoma in some regions and ambiguous differentiation in others. Tracking single cells indicated the existence of cells with bipotential differentiation toward SCNEC and adenocarcinomas. Single-cell transcriptional analysis identified three distinct clusters: SCNEC-like, adenocarcinoma-like, and a cluster lacking specific differentiation markers. The expression of neuroendocrine markers was enriched in the SCNEC-like cluster but not exclusively. Human papillomavirus 18 E6 was enriched in the SCNEC-like cluster, which showed higher proliferation and lower levels of the p53 pathway. After treatment with anticancer drugs, the expression of adenocarcinoma markers increased, whereas that of SCNEC decreased. Using a reporter system for keratin 19 expression, changes in the differentiation of each cell were shown to be associated with the shift in differentiation induced by drug treatment. These data suggest that mixed SCNEC/cervical tumors have a clonal origin and are characterized by an ambiguous and flexible differentiation state.

Mechanism of salidroside in the treatment of endometrial cancer based on network pharmacology and molecular docking

Salidroside is a natural product of phenols, which has a wide scape of pharmacological effects, but its pharmacological effects and molecular mechanism on endometrial cancer are not clear. To systematically explore the pharmacological effects and molecular mechanisms of salidroside on endometrial cancer through the method of network pharmacology. The possible target genes of salidroside were obtained through different pharmacological databases and analysis platforms, and then the relevant target genes of endometrial cancer were obtained through the GeneCards website, and the target genes were uniformly converted into standardized gene names with Uniprot. The collected data were then processed to obtain common target genes and further analyzed through the String website to construct a protein-protein interaction (PPI) network, followed by gene ontology (GO) functional annotation and Kyoto Gene and Genome Encyclopedia (KEGG) pathway analysis. We further interpreted the molecular mechanism of salidroside for the treatment of endometrial cancer by constructing a "drug component-target gene-disease" network. Finally, we performed molecular docking to validate the binding conformation between salidroside and the candidate target genes. There were 175 target genes of salidroside after normalization, among which 113 target genes interacted with endometrial cancer. GO analysis indicated that the anti-endometrial cancer effect of salidroside may be strongly related to biological processes such as apoptosis and response to drug. KEGG analysis indicated that its mechanism may be related to pathway in cancer and PI3K-AKT signaling pathway. Molecular docking showed that salidroside had high affinity with five key genes. Based on the novel network pharmacology and molecular docking validation research methods, we have revealed for the first time the potential mechanism of salidroside in the therapy of endometrial cancer.

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

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

Anti-cancer effect of afatinib, dual inhibitor of HER2 and EGFR, on novel mutation HER2 E401G in models of patient-derived cancer

BACKGROUND

Precision medicine with gene panel testing based on next-generation sequencing for patients with cancer is being used increasingly in clinical practice. HER2, which encodes the human epidermal growth factor receptor 2 (HER2), is a potentially important driver gene. However, therapeutic strategies aimed at mutations in the HER2 extracellular domain have not been clarified. We therefore investigated the effect of EGFR co-targeted therapy with HER2 on patient-derived cancer models with the HER2 extracellular domain mutation E401G, based on our previous findings that this mutation has an epidermal growth factor receptor (EGFR)-mediated activation mechanism.

METHODS

We generated a xenograft (PDX) and a cancer tissue-originated spheroid (CTOS) from a patient's cancer containing an amplified HER2 E401G mutation. With these platforms, we compared the efficacy of afatinib, a tyrosine kinase inhibitor having anti-HER2 and anti-EGFR activity, with two other therapeutic options: lapatinib, which has similar properties but weaker EGFR inhibition, and trastuzumab plus pertuzumab, for which evidence exists of treatment efficacy against cancers with wild-type HER2 amplification. Similar experiments were also performed with H2170, a cell line with wild-type HER2 amplification, to contrast the characteristics of these drug's efficacies against HER2 E401G.

RESULTS

We confirmed that PDX and CTOS retained morphological and immunohistochemical characteristics and HER2 gene profiles of the original tumor. In both PDX and CTOS, afatinib reduced tumor size more than lapatinib or trastuzumab plus pertuzumab. In addition, afatinib treatment resulted in a statistically significant reduction in HER2 copy number at the end of treatment. On the other hand, in H2170 xenografts with wild-type HER2 amplification, trastuzumab plus pertuzumab was most effective.

CONCLUSIONS

Afatinib, a dual inhibitor of HER2 and EGFR, showed a promising effect on cancers with amplified HER2 E401G, which have an EGFR-mediated activation mechanism. Analysis of the activation mechanisms of mutations and development of therapeutic strategies based on those mechanisms are critical in precision medicine for cancer patients.

Three-Dimensional 3D Culture Models in Gynecological and Breast Cancer Research

Traditional two-dimensional (2D) monolayer cell cultures have long been the gold standard for cancer biology research. However, their ability to accurately reflect the molecular mechanisms of tumors occurring in vivo is limited. Recent development of three-dimensional (3D) cell culture models facilitate the possibility to better recapitulate several of the biological and molecular characteristics of tumors in vivo, such as cancer cells heterogeneity, cell-extracellular matrix interactions, development of a hypoxic microenvironment, signaling pathway activities depending on contacts with extracellular matrix, differential growth kinetics, more accurate drugs response, and specific gene expression and epigenetic patterns. In this review, we discuss the utilization of different types of 3D culture models including spheroids, organotypic models and patient-derived organoids in gynecologic cancers research, as well as its potential applications in oncological research mainly for screening drugs with major physiological and clinical relevance. Moreover, microRNAs regulation of cancer hallmarks in 3D cell cultures from different types of cancers is discussed.

HSP90 promotes radioresistance of cervical cancer cells via reducing FBXO6 mediated CD147 polyubiquitination

HSP90 inhibition might be a promising strategy to overcome the radioresistance of some cancers. In the current study, we further explored the mechanisms of HSP90 in regulating the radiosensitivity of cervical cancer cells. Bioinformatic analysis was performed based on data from TCGA‐CESC. Cellular and molecular studies were conducted using CaSki and SiHa and the derived radioresistant (RR) subclones. Through a proteomics screen, we identified HSP90 chaperones (both HSP90α and HSP90β) as CD147‐binding partners supporting its stabilization. Targeting HSP90 sensitized CaSki‐RR and SiHa‐RR cancer cells to irradiation partially through CD147 destabilization. Mechanistically, HSP90 interacts with FBXO6 and reduces FBXO6‐mediated proteasomal degradation of CD147. Enforced FBXO6 overexpression also sensitized CaSki‐RR and SiHa‐RR cancer cells to irradiation. These effects were enhanced using 17‐AAG treatment but were weakened by CD147 overexpression. Survival analysis further confirmed the association between high FBXO6 expression and favorable progression‐free survival among patients with cervical cancer. In conclusion, this study showed that HSP90 promotes radioresistance of cervical cancer cells partially via reducing FBXO6 mediated CD147 polyubiquitination. These findings help to explain why HSP90 inhibitor exerts radio‐sensitizing effects in cervical cancer.

Changes in Stem Cell Regulation and Epithelial Organisation during Carcinogenesis and Disease Progression in Gynaecological Malignancies

Simple Summary

Recent advances in our understanding of the stem cell potential in adult tissues have far-reaching implications for cancer research, and this creates new opportunities for the development of new therapeutic strategies. Here we outline changes in stem cell biology that characterize main gynaecological malignancies, ovarian, endometrial, and cervical cancer, and focus on specific differences between them. We highlight the importance of the local niche environment as a driver of malignant transformation in addition to mutations in key cancer-driving genes. Patient-derived organoids capture in vitro main aspects of cancer tissue architecture and stemness regulatory mechanisms, thus providing a valuable new platform for a personalized approach in the treatment of gynecological malignancies. This review summarizes the main achievement and formulates remaining open questions in this fast-evolving research field.

Abstract

Gynaecological malignancies represent a heterogeneous group of neoplasms with vastly different aetiology, risk factors, molecular drivers, and disease outcomes. From HPV-driven cervical cancer where early screening and molecular diagnostics efficiently reduced the number of advanced-stage diagnosis, prevalent and relatively well-treated endometrial cancers, to highly aggressive and mostly lethal high-grade serous ovarian cancer, malignancies of the female genital tract have unique presentations and distinct cell biology features. Recent discoveries of stem cell regulatory mechanisms, development of organoid cultures, and NGS analysis have provided valuable insights into the basic biology of these cancers that could help advance new-targeted therapeutic approaches. This review revisits new findings on stemness and differentiation, considering main challenges and open questions. We focus on the role of stem cell niche and tumour microenvironment in early and metastatic stages of the disease progression and highlight the potential of patient-derived organoid models to study key events in tumour evolution, the appearance of resistance mechanisms, and as screening tools to enable personalisation of drug treatments.

Heterogenous chemosensitivity of a panel of organoid lines derived from small cell neuroendocrine carcinoma of the uterine cervix

Small cell neuroendocrine carcinoma (SCNEC) of the uterine cervix is a rare disease with a poor prognosis. The lack of established disease models has hampered therapy development. We generated a panel of cancer tissue-originated spheroid (CTOS) lines derived from SCNEC of the uterine cervix using a method based upon cell-cell contact throughout the preparation and culturing processes. Using 11 CTOS lines, we assessed the sensitivity of various drugs used in clinical practice. Drug sensitivity assays revealed significant heterogeneous inter-CTOS chemosensitivity. Microarray analyses were then performed to identify sensitivity-related gene signatures. Specific gene sets were identified which likely contribute to the sensitivity to the tested drugs. We identified a line (Cerv54) that was exceptionally sensitive to irinotecan. Cerv54 had increased levels of CES1, which catalyzes the conversion of irinotecan to the active form, SN38, although in Cerv54 cells, SN38 was undetectable, CES1 expression and activity were markedly low compared to the liver, and a CES1 inhibitor had no effect on irinotecan sensitivity. These results suggested a novel irinotecan mode of action in Cerv54. Our CTOS lines may be useful for understanding the variation and mechanism of drug sensitivity, contributing to the understanding and development of chemotherapeutic drugs.

Three dimensional cultivation increases chemo- and radioresistance of colorectal cancer cell lines

Although 2D cell cultures are commonly used to predict therapy response, it has become clear that 3D cultures may better mimic the in vivo situation and offer the possibility of tailoring translational clinical approaches. Here, we compared the response of 2D and 3D colorectal cancer (CRC) cell lines to irradiation and chemotherapy. Classic 2D cultures and 3D spheroids of CRC cell lines (CaCo2, Colo205, HCT116, SW480) were thoroughly established, then irradiated with doses of 1, 4, or 10 Gy, using a clinical-grade linear accelerator. The response was assessed by immunohistochemistry, flow cytometry, and TUNEL assays. Upon irradiation, CRC 3D spheroids were morphologically altered. After irradiation with 10 Gy, annexin V/PI staining revealed a 1.8- to 4-fold increase in the apoptosis rate in the 2D cell cultures (95% CI 3.24±0.96), and a 1.5- to 2.4-fold increase in the 3D spheroids (95% CI 1.56±0.41). Irradiation with 1 Gy caused 3- and 4-fold increases in TUNEL positive cells in the CaCo2 and HCT116 (p = 0.01) 2D cultures, respectively, compared with a 2-fold increase in the 3D spheroids. Furthermore, the 2D and 3D cultures responded differently to chemotherapy; the 3D cultures were more resistant to 5-FU and cisplatin, but not to doxorubicin and mitomycin C, than the 2D cultures. Taken together, CRC cells cultured as 3D spheroids displayed markedly higher resistance to irradiation therapy and selected chemotherapeutic drugs than 2D cultures. This in vitro difference must be considered in future approaches for determining the ideal in vitro systems that mimic human disease.

Organoid models in gynaecological oncology research

Cell culture and animal models represent experimental cornerstones for the investigation of tissue, organ and body physiology in the context of gynaecological research. However, their ability to accurately reflect human mechanisms in vivo is limited. The development of organoid technologies has begun to address this limitation by providing platforms ex vivo that resemble the phenotype and genotype of the multi-cellular tissue from which they were derived more accurately. In this review, we discuss advances in organoid derivation from endometrial, ovarian, fallopian tube and cervical tissue, both benign and malignant, the manipulation of organoid microenvironment to preserve stem cell populations and achieve long-term expansion and we explore the morphological and molecular kinship of organoids to parent tissue. Apart from providing new insight into mechanisms of carcinogenesis, gynaecological cancer-derived organoids can be utilised as tools for drug screening of chemotherapeutic and hormonal compounds where they exhibit interpatient variability consistent with states in vivo and xenografted tumours allowing for patient-tailored treatment strategies. Bridging organoid with bioengineering accomplishments is clearly the way forward to the generation of organoid-on-a-chip technologies enhancing the robustness of the model and its translational potential. Undeniably, organoids are expected to stand their ground in the years to come and revolutionize development and disease modelling studies.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Dedifferentiation of neuroendocrine carcinoma of the uterine cervix in hypoxia

Neuroendocrine carcinoma of small cell type (SCNEC) is a rare pathological subtype in cervical cancer, which has a worse prognosis than other histological cell types. Due to its low incidence and the lack of experimental platforms, the molecular characteristics of SCNEC in the cervix remain largely unknown. Using the cancer tissue-originated spheroid (CTOS) method-an ex vivo 3D culture system that preserves the differentiation status of the original tumors-we established a panel of CTOS lines of SCNEC. We demonstrated that xenograft tumors and CTOSs, respectively, exhibited substantial intra-tumor and intra-CTOS variation in the expression levels of chromogranin A (CHGA), a neuroendocrine tumor marker. Since hypoxia affects differentiation in various tumors and in stem cells, we also investigated how hypoxia affected neuroendocrine differentiation of SCNEC of the uterine cervix. In the CTOS line cerv21, hypoxia suppressed expression of the neuroendocrine markers CHGA and synaptophysin (SYP). Flow cytometry analysis using CD99 (a membrane protein marker of SCNEC) revealed decreased CD99 expression in a subset of cells under hypoxic conditions. These expression changes were attenuated by HIF-1α knockdown, and by a Notch inhibitor, suggesting that these molecules played a role in the regulation of neuroendocrine differentiation. The examined SCNEC markers were suppressed under hypoxia in multiple CTOS lines. Overall, our present results indicated that neuroendocrine differentiation in SCNEC of the uterus is a variable phenotype, and that hypoxia may be one of the factors regulating the differentiation status.

Hydrodynamic stress stimulates growth of cell clusters via the ANXA1/PI3K/AKT axis in colorectal cancer

Cancer cells are exposed to various stresses in vivo, including hydrodynamic stress (HDS). HDS on cancer cells in the blood stream can influence the metastatic potential. Recent studies revealed that circulating tumor cell clusters are more responsible for metastasis than circulating single cells. Nevertheless, most studies on HDS are based on single cells prepared from established cancer cell lines. Here, we used cancer tissue-originated spheroids (CTOS) as a patient-derived, 3D organoid model to investigate the effect of HDS on cancer cell clusters. We found that HDS induced the growth of cancer cell clusters in a population of colorectal CTOSs. Microarray analyses revealed that the multifunctional protein, Annexin 1 (ANXA1), was upregulated upon HDS exposure. Chemically-induced membrane damage also triggered the expression of ANXA1. A knockdown of ANXA1 revealed that ANXA1 regulated HDS-stimulated growth in colorectal CTOSs. Mechanistically, activating the PI3K/AKT pathway downstream of ANXA1 contributed to the phenotype. These findings demonstrate that HDS induces the growth of cancer cell clusters via ANXA1/PI3K/AKT axis, which helps to elucidate the pro-metastatic feature of circulating cancer cell clusters.

Small Cell Carcinomas of the Uterine Cervix and Lung: Proteomics Reveals Similar Protein Expression Profiles

Objective

The phenotypic and pathological features of small cell cervical carcinoma (SMCC) and small small cell lung cancer (SCLC) are very similar; thus, the chemotherapy regimens used for the rare SMCC have been routinely based on regimens used for common SCLC. We set out to explore the protein expression profile similarities between these 2 cancers to prove that linking their therapeutic regimens is justified, with a secondary aim of finding tumor-specific proteins to use as additional biomarkers for more accurate diagnosis of SMCC, and potentially to use as therapeutic targets.

Methods

Protein expression analysis was performed for 3 cases of SMCC and 1 example each of SCLC, mucinous adenocarcinoma of the cervix (MACC), lung mucinous adenocarcinoma (MACL), and squamous cell carcinoma of the cervix (SCC). We used cancer tissue–originated spheroids (CTOS) and isobaric tags for relative and absolute quantitation (iTRAQ)–based comprehensive and quantitative protein expression profile analysis. Expression in corresponding clinical samples was verified by immunohistochemistry.

Results

Rather than organ of origin–specific patterns, the SMCC and SCLC samples revealed remarkably similar protein expression profiles—in agreement with their matching tumor pathology phenotypes. Sixteen proteins were expressed at least 2-fold higher in both small cell carcinomas (SMCC and SCLC) than in MACC or SCC. Immunohistochemical analysis confirmed higher expression of creatine kinase B-type in SMCC, compared with MACC and SCC.

Conclusions

We demonstrate a significant overlapping similarity of protein expression profiles of lung and cervical small cell carcinomas despite the significant differences in their organs of origin.

Application of Cancer Organoid Model for Drug Screening and Personalized Therapy

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

High-throughput screening in colorectal cancer tissue-originated spheroids

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

Promotion of malignant phenotype after disruption of the three-dimensional structure of cultured spheroids from colorectal cancer

Individual and small clusters of cancer cells may detach from the edges of a main tumor and invade vessels, which can act as the origin of metastasis; however, the mechanism for this phenomenon is not well understood. Using cancer tissue-originated spheroids, we studied whether disturbing the 3D architecture of cancer spheroids can provoke the reformation process and progression of malignancy. We developed a mechanical disruption method to achieve homogenous disruption of the spheroids while maintaining cell–cell contact. After the disruption, 9 spheroid lines from 9 patient samples reformed within a few hours, and 3 of the 9 lines exhibited accelerated spheroid growth. Marker expression, spheroid forming capacity, and tumorigenesis indicated that stemness increased after spheroid disruption. In addition, the spheroid forming capacity increased in 6 of 11 spheroid lines. The disruption signature determined by gene expression profiling supported the incidence of remodeling and predicted the prognosis of patients with colorectal cancer. Furthermore, WNT and HER3 signaling were increased in the reformed spheroids, and suppression of these signaling pathways attenuated the increased proliferation and stemness after the disruption. Overall, the disruption and subsequent reformation of cancer spheroids promoted malignancy-related phenotypes through the activation of the WNT and ERBB pathways.

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

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

3D modeling of cancer stem cell niche

Cancer stem cells reside in a distinct microenvironment called niche. The reciprocal interactions between cancer stem cells and niche contribute to the maintenance and enrichment of cancer stem cells. In order to simulate the interactions between cancer stem cells and niche, three-dimensional models have been developed. These in vitro culture systems recapitulate the spatial dimension, cellular heterogeneity, and the molecular networks of the tumor microenvironment and show great promise in elucidating the pathophysiology of cancer stem cells and designing more clinically relavant treatment modalites.

In vivo and ex vivo cetuximab sensitivity assay using three-dimensional primary culture system to stratify KRAS mutant colorectal cancer

In clinic, cetuximab, an anti-EGFR antibody, improves treatment outcomes in colorectal cancer (CRC). KRAS-mutant CRC is generally resistant to cetuximab, although difference of the sensitivity among KRAS-mutants has not been studied in detail. We previously developed the cancer tissue-originated spheroid (CTOS) method, a primary culture method for cancer cells. We applied CTOS method to investigate whether ex vivo cetuximab sensitivity assays reflect the difference in sensitivity in the xenografts. Firstly, in vivo cetuximab treatment was performed with xenografts derived from 10 CTOS lines (3 KRAS-wildtype and 7 KRAS mutants). All two CTOS lines which exhibited tumor regression were KRAS-wildtype, meanwhile all KRAS-mutant CTOS lines grew more than the initial size: were resistant to cetuximab according to the clinical evaluation criteria, although the sensitivity was quite diverse. We divided KRAS-mutants into two groups; partially responsive group in which cetuximab had a substantial growth inhibitory effect, and resistant group which exhibited no effect. The ex vivo signaling assay with EGF stimulation revealed that the partially responsive group, but not the resistant group, exhibited suppressed ERK phosphorylation ex vivo. Furthermore, two lines from the partially responsive group, but none of the lines in the resistant group, exhibited a combinatory effect of cetuximab and trametinib, a MEK inhibitor, ex vivo and in vivo. Taken together, the results indicate that ex vivo signaling assay reflects the difference in sensitivity in vivo and stratifies KRAS mutant CTOS lines by sensitivity. Therefore, coupling the in vivo and ex vivo assays with CTOS can be a useful platform for understanding the mechanism of diversity in drug sensitivity.

Enhanced efficacy of adjuvant chemotherapy and radiotherapy in selected cases of surgically resected neuroendocrine carcinoma of the uterine cervix: A retrospective cohort study

The aim of the present study is to identify the prognostic factors of overall survival and examine the effects of adjuvant chemotherapy and radiotherapy on the overall survival in neuroendocrine carcinoma of the uterine cervix (NECUC) patients.Forty-eight surgically treated patients were retrospectively recruited and clinicopathologic characteristics and treatments were reviewed. Kaplan-Meier product-limit method and Cox proportional-hazards regression were utilized for univariate and multivariate analyses.The median follow-up time was 20.6 months and the median overall survival was 30.7 months. The estimated 2-year and 5-year overall survival rates were 57.5% and 31.3%, respectively. Forty patients had ≤ stage IIA disease and 8 had >IIA disease. Univariate analysis identified the clinical stage ≤ IIA (P = 0.042), tumor size ≤ 4 cm (P = 0.005), negative lymph nodes metastasis (P < 0.001), depth of stromal invasion ≤ 1/2 (P = 0.001), negative parametrial involvement (P = 0.004), and weak staining of synaptophysin (P = 0.037), and chromogranin (P = 0.011) as the prognostic factors for an improved overall survival, while chemotherapy and radiotherapy were not prognostic factors in the whole cohort. However, surgery combined with chemotherapy and radiotherapy produced a survival advantage over surgery alone in patients with large tumors (P = 0.006). The combination of surgery and chemotherapy (with or without radiotherapy) did not show any significant difference in overall survival for small tumors (P = 0.816), compared with no chemotherapy (with or without radiotherapy). In addition, radiotherapy for tumors with squamous cell carcinoma or adenocarcinoma components achieved a better survival (P = 0.01), and there was a tendency of an unfavorable survival for radiotherapy in homogeneous carcinoma (P = 0.099). Tumor size was an independent prognostic factor in the multivariate analysis (HR: 12.724, 95% CI: 1.697-95.423, P = 0.013).In conclusion, clinicopathologic features significantly influence a NECUC patient's outcome. Tumor size and tumor histology can influence the effect of adjuvant chemotherapy and radiotherapy on overall survival. We recommend that platinum-based adjuvant chemotherapy should be used in all cases, while radiotherapy should be reserved for the selected NECUC patients whose tumors have mixed histology.

J. W, Krakstad C, Haldorsen IS. Tissue and imaging biomarkers for hypoxia predict poor outcome in endometrial cancer

Hypoxia is frequent in solid tumors and linked to aggressive phenotypes and therapy resistance. We explored expression patterns of the proposed hypoxia marker HIF-1α in endometrial cancer (EC) and investigate whether preoperative functional imaging parameters are associated with tumor hypoxia. Expression of HIF-1α was explored both in the epithelial and the stromal tumor component. We found that low epithelial HIF-1α and high stromal HIF-1α expression were significantly associated with reduced disease specific survival in EC. Only stromal HIF-1α had independent prognostic value in Cox regression analysis. High stromal HIF-1α protein expression was rare in the premalignant lesions of complex atypical hyperplasia but increased significantly to invasive cancer. High stromal HIF-1α expression was correlated with overexpression of important genes downstream from HIF-1α, i.e. VEGFA and SLC2A1 (GLUT1). Detecting hypoxic tumors with preoperative functional imaging might have therapeutic benefits. We found that high stromal HIF-1α expression associated with high total lesion glycolysis (TLG) at PET/CT. High expression of a gene signature linked to hypoxia also correlated with low tumor blood flow at DCE-MRI and increased metabolism measured by FDG-PET. PI3K pathway inhibitors were identified as potential therapeutic compounds in patients with lesions overexpressing this gene signature. In conclusion, we show that high stromal HIF-1α expression predicts reduced survival in EC and is associated with increased tumor metabolism at FDG-PET/CT. Importantly; we demonstrate a correlation between tissue and imaging biomarkers reflecting hypoxia, and also possible treatment targets for selected patients.

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

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

Drug screening and grouping by sensitivity with a panel of primary cultured cancer spheroids derived from endometrial cancer

Several molecular targeting drugs are being evaluated for endometrial cancer; selecting patients whose cancers are sensitive to these agents is of paramount importance. Previously, we developed the cancer tissue-originated spheroid method for primary cancer cells taken from patients' tumors as well as patient-derived xenografts. In this study, we successfully prepared and cultured cancer tissue-originated spheroids from endometrial cancers. Characteristics of the original tumors were well retained in cancer tissue-originated spheroids including morphology and expression of p53 or neuroendocrine markers. We screened 79 molecular targeting drugs using two cancer tissue-originated spheroid lines derived from endometrioid adenocarcinoma grade 3 and serous adenocarcinoma. Among several hits, we focused on everolimus, a mammalian target of rapamycin complex 1 inhibitor, and YM155, a survivin inhibitor. When sensitivity to everolimus or YM155 was assessed in 12 or 11 cancer tissue-originated spheroids, respectively, from different endometrial cancer patients, the sensitivity varied substantially. The cancer tissue-originated spheroids sensitive to everolimus showed remarkable suppression of proliferation. The phosphorylation status of the mammalian target of rapamycin complex 1 downstream molecules before and after everolimus treatment did not predict the effect of the drug. In contrast, the cancer tissue-originated spheroids sensitive to YM155 showed remarkable cell death. The effect of YM155 was also confirmed in vivo. The histological type correlated with YM155 sensitivity; non-endometrioid adenocarcinomas were sensitive and endometrioid adenocarcinomas were resistant. Non-canonical autophagic cell death was the most likely cause of cell death in a sensitive cancer tissue-originated spheroid. Thus, sensitivity assays using cancer tissue-originated spheroids from endometrial cancers may be useful for screening drugs and finding biomarkers.

Patient-Derived Xenografts as a Model System for Radiation Research

The cancer literature is filled with promising preclinical studies demonstrating impressive efficacy for new therapeutics, yet translation of these approaches into clinical successes has been rare, indicating that current methods used to predict efficacy are suboptimal. The most likely reason for the limitation of these studies is the disconnect between preclinical models and cancers treated in the clinic. Specifically, most preclinical models are poor representations of human disease. Immortalized cancer cell lines that dominate the cancer literature may be, in a sense, "paper tigers" that have been selected by decades of culture to be artificially driven by highly targetable proteins. Thus, although effective in treating these cell lines either in vitro or as artificial tumors transplanted from culture into experimental animals as xenografts, the identified therapies would likely underperform in a clinical setting. This inherent limitation applies not only to drug testing but also to experiments with radiation therapy. Indeed, traditional radiobiology methods rely on monolayer culture systems, with emphasis on colony formation and DNA damage assessment that may have limited clinical translation. As such, there has been keen interest in developing tumor explant systems in which patient tumors are directly transplanted into and solely maintained in vivo, using immunocompromised mice. These so-called patient-derived xenografts (PDXs) represent a robust model system that has been garnering support in academia and industry as a superior preclinical approach to drug testing. Likewise, PDX models have the potential to improve radiation research. In this review, we describe how PDX models are currently being used for both drug and radiation testing and how they can be incorporated into a translational research program.