Molecular portraits of intratumoral heterogeneity in human ovarian cancer

A computational approach for analysis of intratumoral heterogeneity and standardized uptake value in PET/CT images1

BACKGROUND

By providing both functional and anatomical information from a single scan, digital imaging technologies like PET/CT and PET/MRI hybrids are gaining popularity in medical imaging industry. In clinical practice, the median value (SUVmed) receives less attention owing to disagreements surrounding what defines a lesion, but the SUVmax value, which is a semi-quantitative statistic used to analyse PET and PET/CT images, is commonly used to evaluate lesions.

OBJECTIVE

This study aims to build an image processing technique with the purpose of automatically detecting and isolating lesions in PET/CT images, as well as measuring and assessing the SUVmed.

METHODS

The pictures are separated into their respective lesions using mathematical morphology and the crescent region, which are both part of the image processing method. In this research, a total of 18 different pictures of lesions were evaluated.

RESULTS

The findings of the study reveal that the threshold is satisfied by both the SUVmax and the SUVmed for most of the lesion types. However, in six instances, the SUVmax and SUVmed values are found to be in different courts.

CONCLUSION

The new information revealed by this study needs to be further investigated to determine if it has any practical value in diagnosing and monitoring lesions. However, results of this study suggest that SUVmed should receive more attention in the evaluation of lesions in PET and CT images.

Ascites-Derived Organoids to Depict Platinum Resistance in Gynaecological Serous Carcinomas

Gynaecological serous carcinomas (GSCs) constitute a distinctive entity among female tumours characterised by a very poor prognosis. In addition to late-stage diagnosis and a high rate of recurrent disease associated with massive peritoneal carcinomatosis, the systematic acquisition of resistance to first-line chemotherapy based on platinum determines the unfavourable outcome of GSC patients. To explore the molecular mechanisms associated with platinum resistance, we generated patient-derived organoids (PDOs) from liquid biopsies of GSC patients. PDOs are emerging as a relevant preclinical model system to assist in clinical decision making, mainly from tumoural tissue and particularly for personalised therapeutic options. To approach platinum resistance in a GSC context, proficient PDOs were generated from the ascitic fluid of ovarian, primary peritoneal and uterine serous carcinoma patients in platinum-sensitive and platinum-resistant clinical settings from the uterine aspirate of a uterine serous carcinoma patient, and we also induced platinum resistance in vitro in a representative platinum-sensitive PDO. Histological and immunofluorescent characterisation of these ascites-derived organoids showed resemblance to the corresponding original tumours, and assessment of platinum sensitivity in these preclinical models replicated the clinical setting of the corresponding GSC patients. Differential gene expression profiling of a panel of 770 genes representing major canonical cancer pathways, comparing platinum-sensitive and platinum-resistant PDOs, revealed cellular response to DNA damage stimulus as the principal biological process associated with the acquisition of resistance to the first-line therapy for GSC. Additionally, candidate genes involved in regulation of cell adhesion, cell cycles, and transcription emerged from this proof-of-concept study. In conclusion, we describe the generation of PDOs from liquid biopsies in the context of gynaecological serous carcinomas to explore the molecular determinants of platinum resistance.

Spatial Heterogeneity in Cytoskeletal Mechanics Response to TGF-β1 and Hypoxia Mediates Partial Epithelial-to-Meshenchymal Transition in Epithelial Ovarian Cancer Cells

Metastatic progression of epithelial ovarian cancer (EOC) involves the partial epithelial-to-mesenchymal transition (EMT) of cancer cells in the primary tumor and dissemination into peritoneal fluid. In part to the high degree of heterogeneity in EOC cells, the identification of EMT in highly epithelial cells in response to differences in matrix mechanics, growth factor signaling, and tissue hypoxia is very difficult. We analyzed different degrees of EMT by tracking changes in cell and nuclear morphology, along with the organization of cytoskeletal proteins. In our analysis, we see a small percentage of individual cells that show dramatic response to TGF-β1 and hypoxia treatment. We demonstrate that EOC cells are spatially aware of their surroundings, with a subpopulation of EOC cells at the periphery of a cell cluster in 2D environments exhibited a greater degree of EMT. These peripheral cancer cells underwent partial EMT, displaying a hybrid of mesenchymal and epithelial characteristics, which often included less cortical actin and more perinuclear cytokeratin expression. Collectively, these data show that tumor-promoting microenvironment conditions can mediate invasive cell behavior in a spatially regulated context in a small subpopulation of highly epithelial clustered cancer cells that maintain epithelial characteristics while also acquiring some mesenchymal traits through partial EMT.

A subregion-based prediction model for local-regional recurrence risk in head and neck squamous cell carcinoma

BACKGROUND AND PURPOSE

Given that the intratumoral heterogeneity of head and neck squamous cell carcinoma may be related to the local control rate of radiotherapy, the aim of this study was to construct a subregion-based model that can predict the risk of local-regional recurrence, and to quantitatively assess the relative contribution of subregions.

MATERIALS AND METHODS

The CT images, PET images, dose images and GTVs of 228 patients with head and neck squamous cell carcinoma from four different institutions of the The Cancer Imaging Archive(TCIA) were included in the study. Using a supervoxel segmentation algorithm called maskSLIC to generate individual-level subregions. After extracting 1781 radiomics and 1767 dosiomics features from subregions, an attention-based multiple instance risk prediction model (MIR) was established. The GTV model was developed based on the whole tumour area and was used to compare the prediction performance with the MIR model. Furthermore, the MIR-Clinical model was constructed by integrating the MIR model with clinical factors. Subregional analysis was carried out through the Wilcoxon test to find the differential radiomic features between the highest and lowest weighted subregions.

RESULTS

Compared with the GTV model, the C-index of MIR model was significantly increased from 0.624 to 0.721(Wilcoxon test, p value< 0.0001). When MIR model was combined with clinical factors, the C-index was further increased to 0.766. Subregional analysis showed that for LR patients, the top three differential radiomic features between the highest and lowest weighted subregions were GLRLM_ShortRunHighGrayLevelEmphasis, GRLM_HghGrayLevelRunEmphasis and GLRLM_LongRunHighGrayLevelEmphasis.

CONCLUSION

This study developed a subregion-based model that can predict the risk of local-regional recurrence and quantitatively assess relevant subregions, which may provide technical support for the precision radiotherapy in head and neck squamous cell carcinoma.

Mapping Spatiotemporal Heterogeneity in Tumor Profiles by Integrating High-Throughput Imaging and Omics Analysis

Intratumoral heterogeneity associates with more aggressive disease progression and worse patient outcomes. Understanding the reasons enabling the emergence of such heterogeneity remains incomplete, which restricts our ability to manage it from a therapeutic perspective. Technological advancements such as high-throughput molecular imaging, single-cell omics, and spatial transcriptomics allow recording of patterns of spatiotemporal heterogeneity in a longitudinal manner, thus offering insights into the multiscale dynamics of its evolution. Here, we review the latest technological trends and biological insights from molecular diagnostics as well as spatial transcriptomics, both of which have witnessed burgeoning growth in the recent past in terms of mapping heterogeneity within tumor cell types as well as the stromal constitution. We also discuss ongoing challenges, indicating possible ways to integrate insights across these methods to have a systems-level spatiotemporal map of heterogeneity in each tumor and a more systematic investigation of the implications of heterogeneity for patient outcomes.

A Machine Learning Model Based on Unsupervised Clustering Multihabitat to Predict the Pathological Grading of Meningiomas

Purpose

We aim to develop and validate a machine learning model by enhanced MRI to determine the pathological grading of meningiomas with unsupervised clustering image analysis method, which are multihabitat to reflect the inherent heterogeneity of tumors.

Materials and Methods

A total of 120 patients with meningiomas confirmed by postoperative pathology were included in the study, including 60 patients with low-grade meningiomas (WHO grade I) and 60 patients with high-grade meningiomas (WHO grade II and WHO grade III). All patients underwent complete head enhanced magnetic resonance scans before surgery or any anti-tumor treatment. Enrolled patients in the group received surgical resection and obtained postoperative pathological data. The patients in the training group (84 people) and the test group (36 people) were randomly divided into two groups according to the ratio of 7 to 3. Multi-habitat features were extracted from MRI images based on enhanced T1. Machine learning method was used to model, which was used to distinguish high-grade meningioma from low-grade meningioma. At the same time, the obtained machine learning model was calibrated and evaluated.

Results

In patients with low-grade meningioma and high-grade meningioma, we found significant differences in Silhouette coefficient (P<0.05). In the machine learning model, the area under the curve was 0.838 in the training group (sensitivity, 67.65%; specificity, 88.82%) and 0.73 in the test group (sensitivity, 69.05%; specificity, 71.43%). After the analysis of calibration curve and decision curve analysis, the model had shown the potential of great application value.

Conclusions

Multi-habitat analysis based on enhanced MRI (T1) could accurately predict the pathological grading of meningiomas. This unsupervised image-based method could reflect the direct heterogeneity between high-grade meningiomas and low-grade meningiomas, which is of great significance for patients' treatment and prevention of recurrence.

Clinically translatable quantitative molecular photoacoustic imaging with liposome-encapsulated ICG J-aggregates

Photoacoustic (PA) imaging is a functional and molecular imaging technique capable of high sensitivity and spatiotemporal resolution at depth. Widespread use of PA imaging, however, is limited by currently available contrast agents, which either lack PA-signal-generation ability for deep imaging or their absorbance spectra overlap with hemoglobin, reducing sensitivity. Here we report on a PA contrast agent based on targeted liposomes loaded with J-aggregated indocyanine green (ICG) dye (i.e., PAtrace) that we synthesized, bioconjugated, and characterized to addresses these limitations. We then validated PAtrace in phantom, in vitro, and in vivo PA imaging environments for both spectral unmixing accuracy and targeting efficacy in a folate receptor alpha-positive ovarian cancer model. These study results show that PAtrace concurrently provides significantly improved contrast-agent quantification/sensitivity and SO₂ estimation accuracy compared to monomeric ICG. PAtrace's performance attributes and composition of FDA-approved components make it a promising agent for future clinical molecular PA imaging.

SCAMP2/5 as diagnostic and prognostic markers for acute myeloid leukemia

The secretory carrier-associated membrane proteins (SCAMPs) are associated with the development of multiple human cancers. The role of SCAMPs in acute myeloid leukemia (AML), however, remains to be identified. In the present study, we explored expression patterns and prognostic value of SCAMPs and network analysis of SCAMPs-related signaling pathways in AML using Oncomine, GEPIA, cBioPortal, LinkedOmics, DAVID and Metascape databases. Genetic alteration analysis revealed that the mutation rate of SCAMP genes was below 1% (9/1272) in AML, and there was no significant correlation between SCAMPs gene mutation and AML prognosis. However, the SCAMP2/5 mRNA levels were significantly higher in AML patients than in healthy controls. Moreover, high mRNA expressions of SCAMP2/4/5 were associated with poor overall survival, which might be due to that SCAMP2/4/5 and their co-expressed genes were associated with multiple pathways related to tumorigenesis and progression, including human T-cell leukemia virus 1 infection, acute myeloid leukemia, mTOR and NF-kappa B signaling pathways. These results suggest that SCAMP2/4/5 are potential prognostic markers for AML, and that SCAMP2 and SCAMP5 individually or in combination may be used as diagnostic markers for AML.

Subregional Radiomics Analysis of PET/CT Imaging with Intratumor Partitioning: Application to Prognosis for Nasopharyngeal Carcinoma

PURPOSE

This work aims to identify intratumoral habitats with distinct heterogeneity based on 2-deoxy-2-[¹⁸F]fluro-D-glucose positron emission tomography (PET)/X-ray computed tomography (CT) imaging, and to develop a subregional radiomics approach to predict progression-free survival (PFS) in patients with nasopharyngeal carcinoma (NPC).

PROCEDURES

In total, 128 NPC patients (85 vs. 43 for primary vs. validation cohorts) who underwent pre-treatment PET/CT scan were enrolled retrospectively. Each tumor was partitioned into several phenotypically consistent subregions based on individual- and population-level clustering. For each subregion, 202 radiomics features were extracted to construct imaging biomarker for prognosis via Cox's proportional hazard model combined with forward stepwise feature selection. Relevance of imaging biomarkers and clinicopathological factors were assessed by multivariate Cox regression analysis and Spearman's correlation analysis. To investigate whether imaging biomarkers could provide complementary prognosis information beyond existing predictors, a scoring system was further developed for risk stratification and compared with AJCC staging system.

RESULTS

Three subregions (denoted as S1, S2, and S3) were discovered with distinct PET/CT imaging characteristics in the two cohorts. The prognostic performance of imaging biomarker S3 outperformed the whole tumor (C-index, 0.69 vs. 0.58; log-rank test, p < 0.001 vs. p = 0.552). Imaging biomarker S3 and AJCC stage were identified as independent predictors (p = 0.011 and 0.042, respectively) after adjusting for clinicopathological factors. The scoring system outperformed the traditional AJCC staging system (log-rank test, p < 0.0001 vs. p = 0.0002 in primary cohort and p = 0.0021 vs. p = 0.0277 in validation cohort, respectively).

CONCLUSIONS

Subregional radiomics analysis of PET/CT imaging has the potential to predict PFS in patients with NPC, which also provides complementary prognostic information for traditional predictors.

The attributes of plakins in cancer and disease: perspectives on ovarian cancer progression, chemoresistance and recurrence

The plakin family of cytoskeletal proteins play an important role in cancer progression yet are under-studied in cancer, especially ovarian cancer. These large cytoskeletal proteins have primary roles in the maintenance of cytoskeletal integrity but are also associated with scaffolds of intermediate filaments and hemidesmosomal adhesion complexes mediating signalling pathways that regulate cellular growth, migration, invasion and differentiation as well as stress response. Abnormalities of plakins, and the closely related spectraplakins, result in diseases of the skin, striated muscle and nervous tissue. Their prevalence in epithelial cells suggests that plakins may play a role in epithelial ovarian cancer progression and recurrence. In this review article, we explore the roles of plakins, particularly plectin, periplakin and envoplakin in disease-states and cancers with emphasis on ovarian cancer. We discuss the potential role the plakin family of proteins play in regulating cancer cell growth, survival, migration, invasion and drug resistance. We highlight potential relationships between plakins, epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs) and discuss how interaction of these processes may affect ovarian cancer progression, chemoresistance and ultimately recurrence. We propose that molecular changes in the expression of plakins leads to the transition of benign ovarian tumours to carcinomas, as well as floating cellular aggregates (commonly known as spheroids) in the ascites microenvironment, which may contribute to the sustenance and progression of the disease. In this review, attempts have been made to understand the crucial changes in plakin expression in relation to progression and recurrence of ovarian cancer.

The miR-181a-SFRP4 Axis Regulates Wnt Activation to Drive Stemness and Platinum Resistance in Ovarian Cancer

Wnt signaling is a major driver of stemness and chemoresistance in ovarian cancer, yet the genetic drivers that stimulate its expression remain largely unknown. Unlike other cancers, mutations in the Wnt pathway are not reported in high-grade serous ovarian cancer (HGSOC). Hence, a key challenge that must be addressed to develop effective targeted therapies is to identify nonmutational drivers of Wnt activation. Using an miRNA sensor-based approach, we have identified miR-181a as a novel driver of Wnt/β-catenin signaling. miR-181a^high primary HGSOC cells exhibited increased Wnt/β-catenin signaling, which was associated with increased stem-cell frequency and platinum resistance. Consistent with these findings, inhibition of β-catenin decreased stem-like properties in miR-181a^high cell populations and downregulated miR-181a. The Wnt inhibitor SFRP4 was identified as a novel target of miR-181a. Overall, our results demonstrate that miR-181a is a nonmutational activator of Wnt signaling that drives stemness and chemoresistance in HGSOC, suggesting that the miR-181a-SFRP4 axis can be evaluated as a novel biomarker for β-catenin-targeted therapy in this disease. SIGNIFICANCE: These results demonstrate that miR-181a is an activator of Wnt signaling that drives stemness and chemoresistance in HGSOC and may be targeted therapeutically in recurrent disease.

Mutant FOXL2C134W Hijacks SMAD4 and SMAD2/3 to Drive Adult Granulosa Cell Tumors

The mutant protein FOXL2^C134W is expressed in at least 95% of adult-type ovarian granulosa cell tumors (AGCT) and is considered to be a driver of oncogenesis in this disease. However, the molecular mechanism by which FOXL2^C134W contributes to tumorigenesis is not known. Here, we show that mutant FOXL2^C134W acquires the ability to bind SMAD4, forming a FOXL2^C134W/SMAD4/SMAD2/3 complex that binds a novel hybrid DNA motif AGHCAHAA, unique to the FOXL2^C134W mutant. This binding induced an enhancer-like chromatin state, leading to transcription of nearby genes, many of which are characteristic of epithelial-to-mesenchymal transition. FOXL2^C134W also bound hybrid loci in primary AGCT. Ablation of SMAD4 or SMAD2/3 resulted in strong reduction of FOXL2^C134W binding at hybrid sites and decreased expression of associated genes. Accordingly, inhibition of TGFβ mitigated the transcriptional effect of FOXL2^C134W. Our results provide mechanistic insight into AGCT pathogenesis, identifying FOXL2^C134W and its interaction with SMAD4 as potential therapeutic targets to this condition. SIGNIFICANCE: FOXL2^C134W hijacks SMAD4 and leads to the expression of genes involved in EMT, stemness, and oncogenesis in AGCT, making FOXL2^C134W and the TGFβ pathway therapeutic targets in this condition. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/17/3466/F1.large.jpg.

Prognostic role of SCAMP family in acute myeloid leukemia

Acute myeloid leukemia (AML) is a malignant disease of myeloid hematopoietic stem or progenitor cells characterized by abnormal proliferation of primary and immature myeloid cells in bone marrow and peripheral blood. Gene mutation and expression profiles can be used as prognosis predictors for different prognostic subgroups. Secretory carrier-associated membrane proteins (SCAMPs) are a multigenic family with five members and act as cell surface vectors in the post-Golgi recycling pathways in mammals. Nevertheless, the prognostic and clinical influence of SCAMP family has hardly ever been illustrated in AML. In our study, expression patterns of SCAMP family (SCAMP1-5) were analyzed in 155 AML patients which were extracted from the Cancer Genome Atlas database. In chemotherapy, only subgroup, higher SCAMP1 level was significantly associated with longer EFS and OS (all P = 0.002), and SCAMP1 was confirmed to be an independent favorable factor in un-transplanted patients by Multivariate analysis (all P < 0.05). Nevertheless, in the allogeneic hematopoietic stem cell transplantation (allo-HSCT) treatment subgroup, none of the SCAMP genes had any effect on the clinical survival. Our study found that high expression level of SCAMP1 is a favorable prognostic factor in AML, but allo-HSCT may neutralize its prognostic effect.

Heterogeneity Diffusion Imaging of gliomas: Initial experience and validation

Objectives

Primary brain tumors are composed of tumor cells, neural/glial tissues, edema, and vasculature tissue. Conventional MRI has a limited ability to evaluate heterogeneous tumor pathologies. We developed a novel diffusion MRI-based method—Heterogeneity Diffusion Imaging (HDI)—to simultaneously detect and characterize multiple tumor pathologies and capillary blood perfusion using a single diffusion MRI scan.

Methods

Seven adult patients with primary brain tumors underwent standard-of-care MRI protocols and HDI protocol before planned surgical resection and/or stereotactic biopsy. Twelve tumor sampling sites were identified using a neuronavigational system and recorded for imaging data quantification. Metrics from both protocols were compared between World Health Organization (WHO) II and III tumor groups. Cerebral blood volume (CBV) derived from dynamic susceptibility contrast (DSC) perfusion imaging was also compared with the HDI-derived perfusion fraction.

Results

The conventional apparent diffusion coefficient did not identify differences between WHO II and III tumor groups. HDI-derived slow hindered diffusion fraction was significantly elevated in the WHO III group as compared with the WHO II group. There was a non-significantly increasing trend of HDI-derived tumor cellularity fraction in the WHO III group, and both HDI-derived perfusion fraction and DSC-derived CBV were found to be significantly higher in the WHO III group. Both HDI-derived perfusion fraction and slow hindered diffusion fraction strongly correlated with DSC-derived CBV. Neither HDI-derived cellularity fraction nor HDI-derived fast hindered diffusion fraction correlated with DSC-derived CBV.

Conclusions

Conventional apparent diffusion coefficient, which measures averaged pathology properties of brain tumors, has compromised accuracy and specificity. HDI holds great promise to accurately separate and quantify the tumor cell fraction, the tumor cell packing density, edema, and capillary blood perfusion, thereby leading to an improved microenvironment characterization of primary brain tumors. Larger studies will further establish HDI’s clinical value and use for facilitating biopsy planning, treatment evaluation, and noninvasive tumor grading.

Feasibility of genomic profiling with next-generation sequencing using specimens obtained by image-guided percutaneous needle biopsy

Aims: The demand for specimen collection for genomic profiling is rapidly increasing in the era of personalized medicine. Percutaneous needle biopsy is recognized as minimally invasive, but the feasibility of comprehensive genomic analysis using next-generation sequencing (NGS) is not yet clear. The purpose of this study was to evaluate the feasibility of genomic analysis using NGS with specimens obtained by image-guided percutaneous needle biopsy with 18-G needles. Patients and methods: Forty-eight patients who participated in a clinical study of genomic profiling with NGS with the specimen obtained by image-guided needle biopsy were included. All biopsies were performed under local anesthesia, with imaging guidance, using an 18-G cutting needle. A retrospective chart review was performed to determine the rate of successful genomic analysis, technical success rate of biopsy procedure, adverse events, rate of success in pathological diagnosis, and cause of failed genomic analysis. Results: The success rate of genomic analysis was 79.2% (38/48). The causes of failure were unprocessed for DNA extraction due to insufficient specimen volume (6/10), insufficient DNA volume (2/10), and deteriorated DNA quality (2/10). The rate of successful genomic analysis excluding NGS analysis that failed for reasons unrelated to the biopsy procedures was 95.2% (40/42). Technical success of biopsy was achieved in all patients without severe adverse events. The rate of success in the pathological diagnosis was 97.9% (47/48). Conclusions: Image-guided needle biopsy specimens using an 18-G cutting needle yielded a successful NGS genomic analysis rate with no severe adverse events and could be an adoptable method for tissue sampling for NGS.

Melanoma tumour vasculature heterogeneity: from mice models to human

Tumour angiogenesis is defined by an anarchic vasculature and irregularities in alignment of endothelial cells. These structural abnormalities could explain the variability in distribution of nanomedicines in various tumour models. Then, the main goal of this study was to compare and to characterize the tumour vascular structure in different mouse models of melanoma tumours (B16F10 and SK-Mel-28) and in human melanomas from different patients. Tumours were obtained by subcutaneous injection of 10⁶ B16F10 and 3.10⁶ SK-Mel-28 melanoma cells in C57BL/6 and nude mice, respectively. Tumour growth was evaluated weekly, while vasculature was analysed through fluorescent labelling via CD31 and desmin. Significant differences in tumour growth and mice survival were evidenced between the two melanoma models. A fast evolution of tumours was observed for B16F10 melanoma, reaching a tumour size of 100 mm³ in 7 days compared to SK-Mel-28 which needed 21 days to reach the same volumes. Important differences in vascularization were exposed between the melanoma models, characterized by a significant enhancement of vascular density and a significant lumen size for mice melanoma models compared to human. Immunostaining revealed irregularities in endothelium structure for both melanoma models, but structural differences of vasculature were observed, characterized by a stronger expression of desmin in SK-Mel-28 tumours. While human melanoma mainly develops capillaries, structural irregularities are also observed on the samples of this tumour model. Our study revealed an impact of cell type and tumour progression on the structural vasculature of melanoma, which could impact the distribution of drugs in the tumour environment.

Expression of C19MC miRNAs in HCC associates with stem-cell features and the cancer-testis genes signature

BACKGROUND

Intratumor heterogeneity of hepatocellular carcinoma (HCC) and, among HCC cell subsets, the cancer stem cell population (hCSC), is responsible for therapeutic resistance and disease relapse.

AIMS

To characterize hCSC-enriched HCCs at the molecular level.

METHODS

Side population (SP) was used to identify the hCSCs in multiple tumor sampling from different patients and primary HCCs cultures. FACS was used to immunoprofile cultures. miRNAs were profiled in samples and correlated to SP. The Cancer Genome Atlas (TCGA) HCC dataset was analyzed to search for signatures associated with C19MC miRNAs expression. Results were confirmed by immunohistochemistry.

RESULTS

The miRNA cluster on chromosome 19 (C19MC) was enriched in SP and in HCCs with a high SP fraction. At the molecular level, an elevated C19MC was correlated with expression of precursor transcripts. In TCGA-HCC series, high C19MC expression identified a subset of patients with poorer prognosis, advanced disease and overexpression of the cancer-testis (CT) antigens. These data were confirmed in an independent cohort of HCCs and at the protein level.

CONCLUSION

C19MC miRNAs and CT antigens overexpression represents a novel oncogenic pathway in a subset of hCSC-enriched HCCs with dismal prognosis. CT antigens are promising immunotherapy targets. Therefore, these molecular signatures could identify HCCs who could benefit from immunotherapy.

Improving cancer detection through combinations of cancer and immune biomarkers: a modelling approach

Background

Early cancer diagnosis is one of the most important challenges of cancer research, since in many cancers it can lead to cure for patients with early stage diseases. For epithelial ovarian cancer (which is the leading cause of death among gynaecologic malignancies) the classical detection approach is based on measurements of CA-125 biomarker. However, the poor sensitivity and specificity of this biomarker impacts the detection of early-stage cancers.

Methods

Here we use a computational approach to investigate the effect of combining multiple biomarkers for ovarian cancer (e.g., CA-125 and IL-7), to improve early cancer detection.

Results

We show that this combined biomarkers approach could lead indeed to earlier cancer detection. However, the immune response (which influences the level of secreted IL-7 biomarker) plays an important role in improving and/or delaying cancer detection. Moreover, the detection level of IL-7 immune biomarker could be in a range that would not allow to distinguish between a healthy state and a cancerous state. In this case, the construction of solution diagrams in the space generated by the IL-7 and CA-125 biomarkers could allow us predict the long-term evolution of cancer biomarkers, thus allowing us to make predictions on cancer detection times.

Conclusions

Combining cancer and immune biomarkers could improve cancer detection times, and any predictions that could be made (at least through the use of CA-125/IL-7 biomarkers) are patient specific.

Surface markers of cancer stem-like cells of ovarian cancer and their clinical relevance

Cancer stem-like cells (CSLCs) are defined as cancer cells with stem cell characteristics. Although CSLCs constitute no more than a few percent of the tumor mass, they play important roles in cancer chemo-resistance, metastasis and disease recurrence. Ovarian cancer (OC) is considered the most aggressive gynecological malignancy in which the role of CSLCs is of major significance, although it remains to be specified. The studies describing ovarian CSLC phenotype vary in the definition of the molecular pattern of expression of the main markers such as CD133, CD44, CD117, and CD24. Stem-like features of OC have been shown to correlate with the clinical course of the disease and permit diagnosis, prognosis and treatment outcome to be improved. Identification of CSLC markers could provide hallmarks which, related to the chemo-resistance of the disease, will facilitate treatment selection. This review describes recent advances in research on stem-like cell status in OC, mainly focusing on surface markers of CSLCs and their clinical relevance.

Mechanisms and Targets Involved in Dissemination of Ovarian Cancer

Ovarian carcinoma is associated with the highest death rate of all gynecological tumors. On one hand, its aggressiveness is based on the rapid dissemination of ovarian cancer cells to the peritoneum, the omentum, and organs located in the peritoneal cavity, and on the other hand, on the rapid development of resistance to chemotherapeutic agents. In this review, we focus on the metastatic process of ovarian cancer, which involves dissemination of, homing to and growth of tumor cells in distant organs, and describe promising molecular targets for possible therapeutic intervention. We provide an outline of the interaction of ovarian cancer cells with the microenvironment such as mesothelial cells, adipocytes, fibroblasts, endothelial cells, and other stromal components in the context of approaches for therapeutic interference with dissemination. The targets described in this review are discussed with respect to their validity as drivers of metastasis and to the availability of suitable efficient agents for their blockage, such as small molecules, monoclonal antibodies or antibody conjugates as emerging tools to manage this disease.

Primary Surgery or Neoadjuvant Chemotherapy in Advanced Ovarian Cancer: The Debate Continues…

Primary debulking surgery (PDS) followed by platinum-based chemotherapy has been the cornerstone of treatment for advanced ovarian cancer for decades. Primary debulking surgery has been repeatedly identified as one of the key factors in improving survival in patients with advanced ovarian cancer, especially when minimal or no residual disease is left behind. Achieving these results sometimes requires extensive abdominal and pelvic surgical procedures and consultation with other surgical teams. Some clinicians who propose a primary chemotherapy approach reported an increased likelihood of leaving no macroscopic disease after surgery and improved patient-reported outcomes and quality-of-life (QOL) measures. Given the ongoing debate regarding the relative benefit of PDS versus neoadjuvant chemotherapy (NACT), tumor biology may aid in patient selection for each approach. Neoadjuvant chemotherapy offers the opportunity for in vivo chemosensitivity testing. Studies are needed to determine the best way to evaluate the impact of NACT in each individual patient with advanced ovarian cancer. Indeed, the biggest utility of NACT may be in research, where this approach provides the opportunity for the investigation of predictive markers, mechanisms of resistance, and a forum to test novel therapies.

Genomic Adequacy from Solid Tumor Core Needle Biopsies of ex Vivo Tissue and in Vivo Lung Masses: Prospective Study

Purpose To identify the variables and factors that affect the quantity and quality of nucleic acid yields from imaging-guided core needle biopsy. Materials and Methods This study was approved by the institutional review board and compliant with HIPAA. The authors prospectively obtained 232 biopsy specimens from 74 patients (177 ex vivo biopsy samples from surgically resected masses were obtained from 49 patients and 55 in vivo lung biopsy samples from computed tomographic [CT]-guided lung biopsies were obtained from 25 patients) and quantitatively measured DNA and RNA yields with respect to needle gauge, number of needle passes, and percentage of the needle core. RNA quality was also assessed. Significance of correlations among variables was assessed with analysis of variance followed by linear regression. Conditional probabilities were calculated for projected sample yields. Results The total nucleic acid yield increased with an increase in the number of needle passes or a decrease in needle gauge (two-way analysis of variance, P < .0001 for both). However, contrary to calculated differences in volume yields, the effect of needle gauge was markedly greater than the number of passes. For example, the use of an 18-gauge versus a 20-gauge biopsy needle resulted in a 4.8-5.7 times greater yield, whereas a double versus a single pass resulted in a 2.4-2.8 times greater yield for 18- versus 20-gauge needles, respectively. Ninety-eight of 184 samples (53%) had an RNA integrity number of at least 7 (out of a possible score of 10). Conclusion With regard to optimizing nucleic acid yields in CT-guided lung core needle biopsies used for genomic analysis, there should be a preference for using lower gauge needles over higher gauge needles with more passes. ^©RSNA, 2016 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on October 21, 2016.

Trends on polymer- and lipid-based nanostructures for parenteral drug delivery to tumors

PURPOSE

The dawn of the state-of-the-art methods of cancer treatments, nano-based delivery systems, has dispensed with the mainstream chemotherapy for being inadequate in yielding productive results and the numerous reported side effects. The popularity of this complementary approach in the course of the last two decades has been primarily attributed to its capacity to elevate the therapeutic index of anticancer drugs as well as removing the impassable delivery barriers in solid tumors with the minimal damage to the normal tissues.

METHODS

The PubMed database was consulted to compile this review.

RESULTS

A wide range of minuscule organic and inorganic nanomaterials, with dimensions not exceeding hundred nanometers, has led to hope for cancer therapy to flare-up once again due to possessing a number of exclusive traits for passive and active tumor targeting, some of which are EPR effect, high interstitial pressure of tumor, overexpressed receptors and angiogenesis. Although a limited number of liposomal and polymer-based therapeutic nanoparticles have gained applicability, a vast number of nanoparticles are still being trailed in order to be fully developed.

CONCLUSIONS

This study provides an overview of the advantages/disadvantages of nanocarriers for cancer drug delivery.

Establishment and Characterization of an In Vitro Model of Ovarian Cancer Stem-like Cells with an Enhanced Proliferative Capacity

The establishment of cancer stem-like cell (CSC) culture systems may be instrumental in devising strategies to fight refractory cancers. Inhibition of the Rho kinase ROCK has been shown to favorably affect CSC spheroid cultures. In this study, we show how ROCK inhibition in human serous ovarian cancer (SOC) cells can help establish a CSC system, which illuminates cancer pathophysiology and its treatment in this setting. In the presence of a ROCK kinase inhibitor, spheroid cultures of SOC cells expressed characteristic CSC markers including ALDH1A1, CD133, and SOX2, along with differentiation and tumorigenic capabilities in mouse xenograft models of human SOC. High expression levels of ALDH, but not CD133, correlated with spheroid formation CSC marker expression and tumor forming capability. In clinical specimens of SOC, high levels of ALDH1A1 correlated with advanced stage and poor prognosis. Pharmacologic or genetic blockade of ALDH blocked cell proliferation and reduced expression of SOX2, the genetic ablation of which abolished spheroid formation, whereas SOX2 overexpression inhibited ALDH1A1 expression and blocked spheroid proliferation. Taken together, our findings illustrated a new method to culture human ovarian CSC, and they defined a reciprocal regulatory relationship between ALDH1A1 and SOX2, which impacts ovarian CSC proliferation and malignant progression.

Effect of targeted ovarian cancer immunotherapy using ovarian cancer stem cell vaccine

Background

Accumulating evidence has shown that different immunotherapies for ovarian cancer might overcome barriers to resistance to standard chemotherapy. The vaccine immunotherapy may be a useful one addition to conditional chemotherapy regimens. The present study investigated the use of vaccine of ovarian cancer stem cells (CSCs) to inhibit ovarian cancer growth.

Methods

CD117⁺CD44⁺CSCs were isolated from human epithelial ovarian cancer (EOC) SKOV3 cell line by using a magnetic-activated cell sorting system. Pre-inactivated CD117⁺CD44⁺CSC vaccine was vacccinated into athymic nude mice three times, and then the mice were challenged subcutaneously with SKOV3 cells. The anti-tumor efficacy of CSC vaccine was envaluated by in vivo tumorigenicity, immune efficient analysis by flow cytometer, and enzyme-linked immunosorbent assays, respectively.

Results

The CD117⁺ CD44⁺CSC vaccine increased anti-ovarian cancer efficacy in that it depressed ovarian cancer growth in the athymic nude mice. Vaccination resulted in enhanced serum IFN-γ, decreased TGF-β levels, and increased cytotoxic activity of natural killer cells in the CD117⁺ CD44⁺CSC vaccine immunized mice. Moreover, the CSC-based vaccine significantly reduced the CD117⁺CD44⁺CSC as well as the aldehyde dehydrogenase 1 positive cell populations in the ovarian cancer tissues in the xenograft mice.

Conclusion

The present study provided the first evidence that human SKOV3 CD117⁺ CD44⁺CSC-based vaccine may induce the anti-ovarian cancer immunity against tumor growth by reducing the CD117⁺CD44⁺CSC population.

Addressing challenges of heterogeneous tumor treatment through bispecific protein-mediated pretargeted drug delivery

Tumors are frequently characterized by genomically and phenotypically distinct cancer cell subpopulations within the same tumor or between tumor lesions, a phenomenon termed tumor heterogeneity. These diverse cancer cell populations pose a major challenge to targeted delivery of diagnostic and/or therapeutic agents, as the conventional approach of conjugating individual ligands to nanoparticles is often unable to facilitate intracellular delivery to the full spectrum of cancer cells present in a given tumor lesion or patient. As a result, many cancers are only partially suppressed, leading to eventual tumor regrowth and/or the development of drug-resistant tumors. Pretargeting (multistep targeting) approaches involving the administration of 1) a cocktail of bispecific proteins that can collectively bind to the entirety of a mixed tumor population followed by 2) nanoparticles containing therapeutic and/or diagnostic agents that can bind to the bispecific proteins accumulated on the surface of target cells offer the potential to overcome many of the challenges associated with drug delivery to heterogeneous tumors. Despite its considerable success in improving the efficacy of radioimmunotherapy, the pretargeting strategy remains underexplored for a majority of nanoparticle therapeutic applications, especially for targeted delivery to heterogeneous tumors. In this review, we will present concepts in tumor heterogeneity, the shortcomings of conventional targeted systems, lessons learned from pretargeted radioimmunotherapy, and important considerations for harnessing the pretargeting strategy to improve nanoparticle delivery to heterogeneous tumors.

Cell surface markers of cancer stem cells: diagnostic macromolecules and targets for drug delivery

The recognition that the persistence of cancer stem cells (CSCs) in patients following chemotherapy can result in disease relapse underscores the necessity to develop therapeutics against those cells. CSCs display a unique repertoire of cell surface macromolecules, which have proven essential for their characterization and isolation. Additionally, CSC-specific cell surface macromolecules or markers provide targets for the development of specific agents to destroy them. In this review, we compiled those cell surface molecules that have been validated as CSC markers for many common blood and solid tumors. We describe the unique chemical and structural features of the most common cell surface markers, as well as recent efforts to deliver chemotherapeutic agents into CSCs by targeting those macromolecules.

Downregulated lincRNA HOTAIR expression in ovarian cancer stem cells decreases its tumorgeniesis and metastasis by inhibiting epithelial-mesenchymal transition

Background

Emerging evidence indicates that dysregulated long intervening non-coding RNA (lincRNA) HOTAIR correlates highly with tumor invasion and metastasis but a link between the high expression of HOTAIR and the metastatic cascade of cancer stem cells (CSCs) needs to be further studied. The purpose of this study was to investigate the effect of down-regulated HOTAIR expression on tumorgeniesis and metastasis of epithelial ovarian cancer (EOC) CSCs. CD117⁺CD44⁺CSCs were isolated from human EOC SKOV3 cell line by using a magnetic-activated cell sorting system, and were then transfected with the expression vector-based small hairpin RNA targeting HOTAIR; the stably transfected cells were selected for the study. Colony-forming, wound-healing, cellular metastasis and tumorigenicity assays were performed.

Results

The results demonstrated that the HOTAIR expression in clinical EOC tissues and SKOV3 CD117⁺CD44⁺CSCs was higher than in SKOV3 tumor tissues and non-CD117⁺CD44⁺CSCs. The CD117⁺CD44⁺-shHOTAIR showed an inhibited HOTAIR expression, reduced cell migration and invasion than CD117⁺CD44⁺- scramble, suggesting the inhibition of an epithelial-mesenchymal transition. Moreover, the downregulated HOTAIR expression in CD117⁺CD44⁺ CSCs significantly decreased the tumor growth and lung metastasis in xenograft mice.

Conclusion

Our findings demonstrated the shHOTAIR-mediated down-regulation of the HOTAIR expression in CD117⁺CD44⁺ CSCs can be a promising new opportunity for future clinical trials.

Imaging intratumor heterogeneity: role in therapy response, resistance, and clinical outcome

Tumors exhibit genomic and phenotypic heterogeneity, which has prognostic significance and may influence response to therapy. Imaging can quantify the spatial variation in architecture and function of individual tumors through quantifying basic biophysical parameters such as CT density or MRI signal relaxation rate; through measurements of blood flow, hypoxia, metabolism, cell death, and other phenotypic features; and through mapping the spatial distribution of biochemical pathways and cell signaling networks using PET, MRI, and other emerging molecular imaging techniques. These methods can establish whether one tumor is more or less heterogeneous than another and can identify subregions with differing biology. In this article, we review the image analysis methods currently used to quantify spatial heterogeneity within tumors. We discuss how analysis of intratumor heterogeneity can provide benefit over more simple biomarkers such as tumor size and average function. We consider how imaging methods can be integrated with genomic and pathology data, instead of being developed in isolation. Finally, we identify the challenges that must be overcome before measurements of intratumoral heterogeneity can be used routinely to guide patient care.

An analysis of polymorphisms within the Wnt signaling pathway in relation to ovarian cancer risk in a Polish population

Background and Objective

The Wnt/β-catenin signaling pathway has been considered to be a factor in the development and progression of ovarian cancer.

Methods

All patients with ovarian cancer and controls were tested for BRCA1 mutations (5382incC, C61G, 4153delA) with HybProbe assays and for BRCA2 mutation (5946delT) using high-resolution melting curve analysis (HRM). Mutation carriers were excluded from the association analysis. We studied nine single nucleotide polymorphisms (SNPs) located in CTNNB1 (β-catenin) [rs4533622, rs2953], APC (rs11954856, rs351771, rs459552), and AXIN2 (rs4074947, rs7224837, rs3923087, rs2240308) in women with ovarian cancer without BRCA1/BRCA2 mutations (n = 228) and controls (n = 282). Genotyping of CTNNB1 rs4533622, rs2953, APC rs351771, AXIN2 rs4074947, rs3923087, and rs2240308 was performed by HRM, while that of APC rs11954856, rs459552 and AXIN2 rs7224837 was conducted by PCR followed by the appropriate restriction enzyme digestion [PCR–restriction fragment length polymorphism (PCR-RFLP)].

Results

The most common BRCA1/BRCA2 mutations were identified in 30 patients with ovarian cancer. These mutations were not found in controls. The lowest p values of the trend test (p_trend) were observed for the APC rs351771 and rs11954856 SNPs in patients with ovarian cancer (p_trend = 0.006 and p_trend = 0.007, respectively). Using a dominant inheritance model, we found that the APC rs11954856 SNP is associated with an increased risk of ovarian cancer development [odds ratio = 2.034 (95 % CI 1.302–3.178); p = 0.002]. We also observed significant allelic differences for the APC rs351771 SNP between patients and controls (p = 0.006).

Conclusion

Our study demonstrated significantly increased APC rs11954856 and rs351771 SNP frequencies in Polish women with ovarian cancer.

Electronic supplementary material

The online version of this article (doi:10.1007/s40291-013-0059-y) contains supplementary material, which is available to authorized users.

Molecular portraits of heterogeneity related to cancer stem cells in human ovarian cancer

PURPOSE

The aim of this study was to investigate molecular portraits of heterogeneity related to cancer stem cells (CSCs) in human ovarian cancer and to access the value in diagnosis and treatment.

METHODS

Sixty specimens were collected in both cytoreductive and re-cytoreductive surgeries of 20 serous papillary ovarian adenocarcinoma cases. Expression density and distribution of 3 CSC markers (CD44, CD133, and CD117) and 3 stemness proteins (Bmi1, Nestin, and Oct3/4) were analyzed by immunohistochemical staining. Pairwise comparisons were performed among their expression in primary, metastasis, and relapsing tumors.

RESULTS

Some molecules presented different localization in 1 tissue, like CD133 and CD117, and all but Oct3/4 expressed differentially in different specimens of 1 case. Compared to primary or metastatic cancers, recurrent cancers show higher expression of CD133, CD117, and Bmi1, as well as higher histological grades.

CONCLUSIONS

Our study indicated that there exist extratumoral and intratumoral heterogeneity in ovarian epithelial cancers related to CSCs. And this is worth further studying.

Reversing paclitaxel resistance in ovarian cancer cells via inhibition of the ABCB1 expressing side population

The majority of deaths in ovarian cancer are caused by recurrent metastatic disease which is usually multidrug resistant. This progression has been hypothesised to be due in part to the presence of cancer stem cells, a subset of cells which are capable of self-renewal and are able to survive chemotherapy and migrate to distant sites. Side population (SP) cells, identified by the efflux of the DNA-binding dye Hoechst 33342 through ATP-binding cassette (ABC) transporters, are a known adult stem cell group and have been suggested as a cancer stem cell in various cancers. Despite the identification of SP cells in cancer cell lines and patient samples, little attention has been paid to the identification of specific ABC transporters within this cell fraction which efflux Hoechst dye and thus may facilitate drug resistance. In this study, we demonstrate that SP cells can be detected in both ovarian cancer cell lines and ascitic fluid samples, and these SP cells possess stem cell and drug resistance properties. We show that ABCB1 is the functioning ABC transporter in ovarian cancer cell lines, and expression of ABCB1 is associated with a paclitaxel-resistant phenotype. Moreover, silencing of ABCB1 using a specific morpholino oligonucleotide results in an inhibition of the SP phenotype and a sensitising of ovarian cancer cell lines to paclitaxel. ABCB1 should therefore be considered as a therapeutic target in ovarian cancer.

Observation of ovarian cancer stem cell behavior and investigation of potential mechanisms of drug resistance in three-dimensional cell culture

Cancer cells behave differently in a three-dimensional (3D) cell culture compared with in the conventional two-dimensional (2D) one. Accumulated evidences indicate that the characteristics of cancer stem cells (CSCs) are different from common cancer cells due to their ability to produce tumors and resist chemoradiation. The objective of this work was to observe CSC behavior and investigate the potential mechanisms of CSC drug resistance in 3D versus 2D in vitro environment. We first demonstrated that the CD44(+)CD117(+)cells isolated from the human epithelial ovarian cancer HO8910 cell line have the properties of CSCs that revealed faster growth, larger tumorsphere and stronger survival potential in the hypoxic environment in 3D cell culture as well as more powerful tumorigenicity in a xenograft mice than the HO8910 cells. The CD44(+)CD117(+)CSCs also exhibited high chemoresistance to anticancer drugs when the cells were incubated with 5-fluorouracil, cisplatin and carboplatin, respectively in 3D versus 2D environment. This might be associated with the high expression of ABCG2, ABCB1 and the high expression of MMP-2 and MMP-9 in CD44(+)CD117(+)CSCs. Overall, these results suggest the advantages of using 3D culture model to accurately display CSC behavior in vitro. 3D model may improve the efficacy of screening anticancer drugs for treatment of ovarian CSCs.

Honokiol as a Radiosensitizing Agent for Colorectal cancers

Radioresistance is a frustrating obstacle for patients with colorectal cancers (CRCs) undergoing radiotherapy. There is an urgent need to find an effective agent to increase the sensitivity of CRCs to radiation. Honokiol, an active compound purified from Magnolia, was found to radiosensitize colorectal cancer cells both in vitro and in vivo. However, the mechanisms control important signaling that enhances radiosensitivity is currently unknown. In this study, we have reviewed important signaling pathways that are closely related to radiosensitization, such as cell cycle arrest, tumor angiogenesis, JAK/STAT3 signaling pathway and Mismatch repair. Studies show that honokiol can interfere with these pathways at different levels. With overall analysis, it may bring light on finding the possible mechanism by which honokiol acts as a radiosensitizing agent for CRCs.

MicroRNA-200c overexpression inhibits tumorigenicity and metastasis of CD117+CD44+ ovarian cancer stem cells by regulating epithelial-mesenchymal transition

Background

Cancer stem cells (CSCs) are believed to be ‘seed cell’ in cancer recurrence and metastasis. MicroRNAs (miRNAs) can play an important role in the progression of primary tumor towards metastasis by regulating the epithelial-mesenchymal transition (EMT). The goal of this study was to investigate the effect of miRNA-200c overexpression on the EMT, tumorigenicity and metastasis of epithelial ovarian cancer (EOC) CSCs.

Methods

The EOC CD117⁺CD44⁺CSCs were isolated from the human ovarian cancer cell line SKOV3 by using a magnetic-activated cell sorting system, and the lentivirus miR-200c transduced CSCs were then selected for the study. The assays of colony forming, wound healing, cellular migration in vitro and tumor progression in vivo were performed.

Results

The miR-200c expression was reduced in the CD117⁺CD44⁺CSCs compared with the non-CD117⁺CD44⁺CSCs. However, the stable overexpression of the miR-200c in the CD117⁺CD44⁺CSCs resulted in a significant down-regulation of ZEB-1 and the Vimentin expression, an upregulation of the E-cadherin expression as well as a decrease of colony forming, migratory and invasion in vitro. Importantly, the miR-200c overexpression significantly inhibited the CD117⁺CD44⁺CSCs xenograft growth and lung metastasis in vivo in nude mice by inhibition of the EMT. In addition, the down-regulation of ZEB-1 showed the same efficacy as the miR-200c overexpression in the CD117⁺CD44⁺CSCs.

Conclusion

These findings from this study suggest that the miR-200c overexpression may be considered a critical approach for the EOC CD117⁺CD44⁺CSCs in clinical trials.

Cancerous ovarian stem cells: obscure targets for therapy but relevant to chemoresistance

Chemotherapy with platinum and taxanes is the first line of treatment for all epithelial ovarian cancer (EOC) patients after debulking surgery. Even though the treatment is initially effective in 80% of patients, recurrent cancer is inevitable in the vast majority of cases. Emerging evidence suggests that some tumor cells can survive chemotherapy by activating the self-renewal pathways resulting in tumor progression and clinical recurrence. These defined population of cells commonly termed as "cancer stem cells" (CSC) may generate the bulk of the tumor by using differentiating pathways. These cells have been shown to be resistant to chemotherapy and, to have enhanced tumor initiating abilities, suggesting CSCs as potential targets for treatment. Recent studies have introduced a new paradigm in ovarian carcinogenesis which proposes in situ carcinoma at the fimbrial end of the fallopian tube to generate high-grade serous ovarian carcinomas, in contrast to ovarian cortical inclusion cysts (CIC) which produce borderline and low grade serous, mucinous, endometrioid, and clear cell carcinomas. This review summarizes recent advances in our understanding of the cellular origin of EOC and the molecular mechanisms defining the basis of CSC in EOC progression and chemoresistance. Using a model ovarian cancer cell line, we highlight the role of CSC in response to chemotherapy, and relate how CSCs may impact on chemoresistance and ultimately recurrence. We also propose the molecular targeting of CSCs and suggest ways that may improve the efficacy of current chemotherapeutic regimens needed for the management of this disease.

CD24⁺ ovary cancer cells exhibit an invasive mesenchymal phenotype

We recently reported that the subset of CD24(+) cells in ovarian cancer possesses various cancer stem cell properties. In this study, we further show that this subpopulation of ovarian cancer cells exhibits an epithelial-mesenchymal transition (EMT) phenotype, high invasive capacity, and CXCR4/SDF-1-mediated chemotactic migration. We evaluated CD24 expression in various ovarian cancer cell lines by flow cytometric analysis. CAOV3 and a primary ovarian cancer cell line Clone 4 were sorted into CD24(+) and CD24(-) subpopulations by FACS and Western blot, cell invasion, adhesion, and in vitro chemotaxis assays were performed with these two subpopulations. We also assessed the effects of shRNA depletion of CD24 in CAOV3 and Clone 4 cells by Western blot and cell invasion assays. CD24 expression in ovarian cancer cell lines correlated with aggressive histologic subtypes of epithelial ovarian cancer. The CD24(+) subpopulation was also more invasive than the CD24(-) subpopulation and showed higher CXCR4/SDF-1-mediated chemotactic migration. CD24(+) cells exhibited an EMT phenotype as characterized by loss of E-cadherin expression and gain of vimentin, Twist, and Snail1 expression. In addition, CD24(+) cells stimulated cell attachment to fibronectin through the activation of β1 integrin. Depletion of CD24 expression by CD24 shRNA efficiently suppressed cell invasion and induced downregulation of CXCR4 as well as loss of the EMT phenotype. In conclusion, CD24 expression in ovarian cancer may be related to tumor aggressiveness, in particular cell invasion and chemotactic migration. Therefore, CD24 may be a good candidate for a therapeutic target for ovarian cancer.

Evaluation of characteristics of CD44+CD117+ ovarian cancer stem cells in three dimensional basement membrane extract scaffold versus two dimensional monocultures

Background

Cancer stem cells (CSCs) are thought to be capable of surviving conventional chemotherapeutic treatments because the cells have more resistant to anticancer drugs than common cancer cells. Most in vitro studies in experimental cancer cells have been done in a two-dimensional (2D) monocultures, while accumulating evidence suggests that cancer cells behave differently when they are grown within a three-dimensional (3D) culture system.

Results

The CD44⁺CD117⁺cells isolated from human epithelial ovarian cancer SKOV-3 cell line using magnetic-activated cell sorting were found to grow faster than the SKOV-3 cells in the 3D culture and in the nude mice. Anticancer drugs 5FU, docetaxel, cisplatin, and carboplatin were seen to inhibit growth of the CD44⁺CD117⁺ cells by 50% in the 2D culture with IC₅₀ concentration, whereas, in the 3D culture, the four drugs inhibited the cell growth by only 34.4%, 40.8%, 34.8% and 21.9% at 3D one, respectively. Effect of paclitaxel on the CD44⁺CD117⁺cell viability indicated that fewer cells underwent apoptosis in 3D culture than that in 2D one. In addition, anticancer drugs markedly increased the expression of ABCG2 and ABCB1 of CD44⁺CD117⁺cells in 3D culture.

Conclusion

Our assay demonstrated that human epithelial ovarian cancer CD44⁺CD117⁺cells possessed the properties of CSCs that exhibited more chemoresistance in the 3D culture than that of in 2D one. The 3D culture provides a realistic model for study of the CSC response to anticancer drugs.

Toward development of a surface-enhanced Raman scattering (SERS)-based cancer diagnostic immunoassay panel

Proteomic analyses of readily obtained human fluids (e.g., serum, urine, and saliva) indicate that the diagnosis of complex diseases will be enhanced by the simultaneous measurement of multiple biomarkers from such samples. This paper describes the development of a nanoparticle-based multiplexed platform that has the potential for simultaneous read-out of large numbers of biomolecules. For this purpose, we have chosen pancreatic adenocarcinoma (PA) as a test bed for diagnosis and prognosis. PA is a devastating form of cancer in which an estimated 86% of diagnoses resulted in death in the United States in 2010. The high mortality rate is due, in part, to the asymptomatic development of the disease and the dearth of sensitive diagnostics available for early detection. One promising route lies in the development of a serum biomarker panel that can generate a signature unique to early stage PA. We describe the design and development of a proof-of-concept PA biomarker immunoassay array coupled with surface-enhanced Raman scattering (SERS) as a sensitive readout method.

Intratumoral heterogeneity in the self-renewal and tumorigenic differentiation of ovarian cancer

Resistance to anticancer therapy has been attributed to interindividual differences in gene expression pathways among tumors, and to the existence within tumors of cancer stem cells with self-renewal capacity. In previous studies, we have demonstrated that the human embryonic stem cell (hESC)-derived cellular microenvironment in immunocompromised mice enables functional distinction of heterogeneous tumor cells, including cells that do not grow into a tumor in conventional direct tumor xenograft platform. In the current study, we use clonally expanded subpopulations derived from ovarian clear cell carcinoma of a single tumor, to demonstrate striking intratumoral phenotypic heterogeneity that is dynamically dependent on the tumor growth microenvironment. Each of six clonally expanded subpopulations displays a different level of morphologic and tumorigenic differentiation, wherein growth in the hESC-derived microenvironment favors growth of CD44+ aldehyde dehydrogenase positive pockets of self-renewing cells that sustain tumor growth through a process of tumorigenic differentiation into CD44- aldehyde dehydrogenase negative derivatives. Strikingly, these derivative cells display microenvironment-dependent plasticity with the capacity to restore self-renewal and CD44 expression. Such intratumoral heterogeneity and plasticity at the level of the key properties of self-renewal and tumorigenic differentiation suggests that a paradigm shift is needed in the approach to anticancer therapy, with the aim of turning malignant growth into a chronic manageable disorder, based on continual monitoring of these tumor growth properties. The hESC-based in vivo model renders intratumoral heterogeneity in the self-renewal and tumorigenic differentiation amenable to biological analysis as well as anticancer therapy testing.

Tumor heterogeneity and its implication for drug delivery

Evidence continues to accumulate that patient tumors contain heterogeneous cell populations, each of which may contribute differently in extent and mechanism to the progression of malignancy. However, the field of tumor drug delivery research, while continually presenting new and innovative approaches, in many ways continues to operate on the premise that essentially all tumor cells are identical. In some in vivo models, xenograft tumors using cell lines may actually be comparatively homogeneous, and thus result in overly encouraging results when a particular drug or delivery system is reported to successfully treat tumors in mice. It is well known, however, that many drugs that show success in preclinical studies will fail in clinical trials. Tumor heterogeneity is possibly one of the most significant factors that most treatment methods fail to address sufficiently. While a particular drug may exhibit initial success, the eventual relapse of tumor growth is due in many cases to subpopulations of cells that are either not affected by the drug mechanism, possess or acquire a greater drug resistance, or have a localized condition in their microenvironment that enables them to evade or withstand the drug. These various subpopulations may include cancer stem cells, mutated clonal variants, and tumor-associated stromal cells, as well as cells experiencing a spatially different condition such as hypoxia within a diffusion-limited tumor region. This review briefly discusses some of the many aspects of tumor heterogeneity and their potential implications for future drug design and delivery methods.

On the epigenetic origin of cancer stem cells

Epigenetic mechanisms are the key component of the dynamic transcriptional programming that occurs along the process of differentiation from normal stem cells to more specialized cells. In the development of cancer and according to the cancer stem cell model, aberrant epigenetic changes may ensure the property of cancer cells to switch cancer stem cell markers on and off in order to generate a heterogeneous population of cells. The tumour will then be composed of tumourigenic (cancer stem cells) and non-tumourigenic (the side population that constitutes the bulk of the tumour) cells. Characterizing epigenetic landscapes may thus help discriminate aberrant marks (good candidates for tumour detection) from cancer stem cell specific profiles. In this review, we will give some insights about what epigenetics can teach us about the origin of cancer stem cells. We will also discuss how identification of epigenetic reprogramming may help designing new drugs that will specifically target cancer stem cells.

Targeted therapy in the management of advanced gastric cancer: are we making progress in the era of personalized medicine?

BACKGROUND

Gastric cancer is one of the leading causes of cancer death. With greater understanding of the molecular basis of carcinogenesis, targeted agents have led to a modest improvement in the outcome of advanced gastric cancer (AGC) patients.

METHODS AND RESULTS

We conducted an overview of the published evidence regarding the use of targeted therapy in AGC patients. Thus far, the human epidermal growth factor receptor (HER) pathway, angiogenic pathway, and phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin pathway have emerged as potential avenues for targeted therapy in AGC patients. The promising efficacy results of the Trastuzumab for Gastric Cancer trial led to the approved use of trastuzumab-based therapy as first-line treatment for patients with HER-2+ AGC. On the other hand, the Avastin® in Gastric Cancer trial evaluating bevacizumab in combination with chemotherapy did not meet its primary endpoint of a longer overall survival duration despite a significantly higher response rate and longer progression-free survival time in patients in the bevacizumab arm. Phase III data are awaited for other targeted agents, including cetuximab, panitumumab, lapatinib, and everolimus.

CONCLUSION

Recent progress in targeted therapy development for AGC has been modest. Further improvement in the outcome of AGC patients will depend on the identification of biomarkers in different patient populations to facilitate the understanding of gastric carcinogenesis, combining different targeted agents with chemotherapy, and unraveling new molecular targets for therapeutic intervention.

Ovarian cancer stem cell markers: prognostic and therapeutic implications

Cancer stem cells are rare chemotherapy resistant cells within a tumor which can serve to populate the bulk of a tumor with more differentiated daughter cells and potentially contribute to recurrent disease. Ovarian cancer is a disease for which at the time of initial treatment we can obtain complete clinical remission in the majority of patients. Unfortunately, most will relapse and succumb to their disease. This clinical course is in line with the cancer stem cell model. In the past 5 years a significant amount of work has been done to identify cells with characteristics of ovarian cancer stem cells. This review will focus specifically on the markers used to define human ovarian cancer stem cells, the prognostic implications of the expression of these cancer stem cell markers in patient's primary tumors, and the potential of these cancer stem cell markers to serve as therapeutic targets.

Modulation of AKT activity is associated with reversible dormancy in ascites-derived epithelial ovarian cancer spheroids

Epithelial ovarian cancer (EOC) metastasis is a direct contributor to high recurrence and low survival for patients with this disease. Metastasis in EOC occurs by cell exfoliation from the primary tumor into the fluid-filled peritoneal cavity, persistence of these cells as non-adherent multicellular aggregates or spheroids and reattachment of spheroids to form secondary lesions. We have recovered native spheroids from ascites fluid and demonstrated that EOC cells within these structures exhibit reduced proliferation, yet regain the capacity to attach and reinitiate cell division. To model this process in vitro for further investigation, primary EOC cells from patient peritoneal fluid were cultured under non-adherent conditions. Here we show that these cells naturally form spheroids resembling those observed in ascites. Spheroids exhibit reduced cell proliferation and a protein expression pattern consistent with cellular quiescence: specifically, decreased phospho-AKT and p45/SKP2 with a concomitant increase in p130/RBL2 and p27(Kip1). However, when spheroids are seeded to an adherent surface, reattachment occurs rapidly and is followed by reinitiation of AKT-dependent cell proliferation. These results were strikingly consistent among numerous clinical specimens and were corroborated in the EOC cell line OVCAR3. Therefore, our data reveal that EOC cells become quiescent when forming spheroids, but reactivate proliferative mechanisms upon attachment to a permissive substratum. Overall, this work utilizes a novel in vitro model of EOC metastasis that employs primary human EOC cells and introduces the important concept of reversible dormancy in EOC pathogenesis.