Stromal compartment as a survival prognostic factor in advanced ovarian carcinoma

The endothelin-1-driven tumor-stroma feed-forward loops in high-grade serous ovarian cancer

The high-grade serous ovarian cancer (HG-SOC) tumor microenvironment (TME) is constellated by cellular elements and a network of soluble constituents that contribute to tumor progression. In the multitude of the secreted molecules, the endothelin-1 (ET-1) has emerged to be implicated in the tumor/TME interplay; however, the molecular mechanisms induced by the ET-1-driven feed-forward loops (FFL) and associated with the HG-SOC metastatic potential need to be further investigated. The tracking of the patient-derived (PD) HG-SOC cell transcriptome by RNA-seq identified the vascular endothelial growth factor (VEGF) gene and its associated signature among those mostly up-regulated by ET-1 and down-modulated by the dual ET-1R antagonist macitentan. Within the ligand-receptor pairs concurrently expressed in PD-HG-SOC cells, endothelial cells and activated fibroblasts, we discovered two intertwined FFL, the ET-1/ET-1R and VEGF/VEGF receptors, concurrently activated by ET-1 and shutting-down by macitentan, or by the anti-VEGF antibody bevacizumab. In parallel, we observed that ET-1 fine-tuned the tumoral and stromal secretome toward a pro-invasive pattern. Into the fray of the HG-SOC/TME double and triple co-cultures, the secretion of ET-1 and VEGF, that share a common co-regulation, was inhibited upon the administration of macitentan. Functionally, macitentan, mimicking the effect of bevacizumab, interfered with the HG-SOC/TME FFL-driven communication that fuels the HG-SOC invasive behavior. The identification of ET-1 and VEGF FFL as tumor and TME actionable vulnerabilities, reveals how ET-1R blockade, targeting the HG-SOC cells and the TME simultaneously, may represent an effective therapeutic option for HG-SOC patients.

Fluorescent imaging probes for in vivo ovarian cancer targeted detection and surgery

Ovarian cancer is the most lethal gynecological cancer, with a survival rate of approximately 40% at five years from the diagno. The first-line treatment consists of cytoreductive surgery combined with chemotherapy (platinum- and taxane-based drugs). To date, the main prognostic factor is related to the complete surgical resection of tumor lesions, including occult micrometastases. The presence of minimal residual diseases not detected by visual inspection and palpation during surgery significantly increases the risk of disease relapse. Intraoperative fluorescence imaging systems have the potential to improve surgical outcomes. Fluorescent tracers administered to the patient may support surgeons for better real-time visualization of tumor lesions during cytoreductive procedures. In the last decade, consistent with the discovery of an increasing number of ovarian cancer-specific targets, a wide range of fluorescent agents were identified to be employed for intraoperatively detecting ovarian cancer. Here, we present a collection of fluorescent probes designed and developed for fluorescence-guided ovarian cancer surgery. Original articles published between 2011 and November 2022 focusing on fluorescent probes, currently under preclinical and clinical investigation, were searched in PubMed. The keywords used were targeted detection, ovarian cancer, fluorescent probe, near-infrared fluorescence, fluorescence-guided surgery, and intraoperative imaging. All identified papers were English-language full-text papers, and probes were classified based on the location of the biological target: intracellular, membrane, and extracellular.

The Complex Tumor Microenvironment in Ovarian Cancer: Therapeutic Challenges and Opportunities

The tumor microenvironment (TME) in ovarian cancer (OC) has much greater complexity than previously understood. In response to aggressive pro-angiogenic stimulus, blood vessels form rapidly and are dysfunctional, resulting in poor perfusion, tissue hypoxia, and leakiness, which leads to increased interstitial fluid pressure (IFP). Decreased perfusion and high IFP significantly inhibit the uptake of therapies into the tumor. Within the TME, there are numerous inhibitor cells, such as myeloid-derived suppressor cells (MDSCs), tumor association macrophages (TAMs), regulatory T cells (Tregs), and cancer-associated fibroblasts (CAFs) that secrete high numbers of immunosuppressive cytokines. This immunosuppressive environment is thought to contribute to the lack of success of immunotherapies such as immune checkpoint inhibitor (ICI) treatment. This review discusses the components of the TME in OC, how these characteristics impede therapeutic efficacy, and some strategies to alleviate this inhibition.

Ovarian Cancer Cell-Conditioning Medium Induces Cancer-Associated Fibroblast Phenoconversion through Glucose-Dependent Inhibition of Autophagy

One aspect of ovarian tumorigenesis which is still poorly understood is the tumor-stroma interaction, which plays a major role in chemoresistance and tumor progression. Cancer-associated fibroblasts (CAFs), the most abundant stromal cell type in the tumor microenvironment, influence tumor growth, metabolism, metastasis, and response to therapy, making them attractive targets for anti-cancer treatment. Unraveling the mechanisms involved in CAFs activation and maintenance is therefore crucial for the improvement of therapy efficacy. Here, we report that CAFs phenoconversion relies on the glucose-dependent inhibition of autophagy. We show that ovarian cancer cell-conditioning medium induces a metabolic reprogramming towards the CAF-phenotype that requires the autophagy-dependent glycolytic shift. In fact, 2-deoxy-D-glucose (2DG) strongly hampers such phenoconversion and, most importantly, induces the phenoreversion of CAFs into quiescent fibroblasts. Moreover, pharmacological inhibition (by proline) or autophagy gene knockdown (by siBECN1 or siATG7) promotes, while autophagy induction (by either 2DG or rapamycin) counteracts, the metabolic rewiring induced by the ovarian cancer cell secretome. Notably, the nutraceutical resveratrol (RV), known to inhibit glucose metabolism and to induce autophagy, promotes the phenoreversion of CAFs into normal fibroblasts even in the presence of ovarian cancer cell-conditioning medium. Overall, our data support the view of testing autophagy inducers for targeting the tumor-promoting stroma as an adjuvant strategy to improve therapy success rates, especially for tumors with a highly desmoplastic stroma, like ovarian cancer.

Detecting the FLJ22447 lncRNA in Ovarian Cancer with Cyclopentane-Modified FIT-PNAs (cpFIT-PNAs)

Ovarian cancer (OC) is one of the most lethal gynecologic cancers that is typically diagnosed at the very late stage of disease progression. Thus, there is an unmet need to develop diagnostic probes for early detection of OC. One approach may rely on RNA as a molecular biomarker. In this regard, FLJ22447 lncRNA is an RNA biomarker that is over-expressed in ovarian cancer (OC) and in cancer-associated fibroblasts (CAFs). CAFs appear early on in OC as they provide a metastatic niche for OC progression. FIT-PNAs (forced intercalation-peptide nucleic acids) are DNA analogs that are designed to fluoresce upon hybridization to their complementary RNA target sequence. In recent studies, we have shown that the introduction of cyclopentane PNAs into FIT-PNAs (cpFIT-PNA) results in superior RNA sensors. Herein, we report the design and synthesis of cpFIT-PNAs for the detection of this RNA biomarker in living OC cells (OVCAR8) and in CAFs. cpFIT-PNA was compared to FIT-PNA and the cell-penetrating peptide (CPP) of choice was either a simple one (four L-lysines) or a CPP with enhanced cellular uptake (CLIP6). The combination of CLIP6 with cpFIT-PNA resulted in a superior sensing of FLJ22447 lncRNA in OVCAR8 cells as well as in CAFs. Moreover, incubation of CLIP6-cpFIT-PNA in OVCAR8 cells leads to a significant decrease (ca. 60%) in FLJ22447 lncRNA levels and in cell viability, highlighting the potential theranostic use of such molecules.

Tumor-Stroma Proportion to Predict Chemoresistance in Patients With Ovarian Cancer

IMPORTANCE

Platinum-based chemotherapy is the backbone of standard-of-care treatment for patients with advanced-stage, high-grade serous carcinoma (HGSC), the most common form of ovarian cancer; however, one-third of patients have or acquire chemoresistance toward platinum-based therapies.

OBJECTIVE

To demonstrate the utility of tumor-stroma proportion (TSP) as a predictive biomarker of chemoresistance of HGSC, progression-free survival (PFS), and overall survival (OS).

DESIGN, SETTING, AND PARTICIPANTS

This prognostic study leveraged tumors from patients with HGSC in The Cancer Genome Atlas (TCGA) cohort (1993-2013) and an independent cohort of resected clinical specimens from patients with HGSC (2004-2014) available in diagnostic and tissue microarray formats from the University of Tübingen in Germany. Data analysis was conducted from January 2021 to January 2024.

EXPOSURE

Diagnosis of HGSC.

MAIN OUTCOMES AND MEASURES

Principal outcome measures were the ability of TSP to predict platinum chemoresistance, PFS, and OS. Using hematoxylin and eosin-stained slides from the Tübingen cohort (used for routine diagnostic assessment from surgical specimens) as well as tissue microarrays, representative sections of tumors for scoring of TSP were identified using previously evaluated cutoffs of 50% stroma or greater (high TSP) and less than 50% stroma (low TSP). Digitized slides from the TCGA Cohort were analyzed and scored in a similar fashion. Kaplan-Meier time-to-event functions were fit to estimate PFS and OS.

RESULTS

The study included 103 patients (mean [SD] age, 61.6 [11.1] years) from the TCGA cohort and 192 patients (mean [SD] age at diagnosis, 63.7 [11.1] years) from the Tübingen cohort. In the TCGA cohort, there was no significant association of TSP levels with chemoresistance, PFS, or OS. However, in the Tübingen cohort, high TSP was associated with significantly shorter PFS (HR, 1.586; 95% CI, 1.093-2.302; P = .02) and OS (hazard ratio [HR], 1.867; 1.249-2.789; P = .002). Patients with chemoresistant tumors were twice as likely to have high TSP as compared to patients with chemosensitive tumors (HR, 2.861; 95% CI, 1.256-6.515; P = .01). In tissue microarrays from 185 patients from the Tübingen cohort, high TSP was again associated with significantly shorter PFS (HR, 1.675; 95% CI, 1.012-2.772 P = .04) and OS (HR, 2.491; 95% CI, 1.585-3.912; P < .001).

CONCLUSIONS AND RELEVANCE

In this prognostic study, TSP was a consistent and reproducible marker of clinical outcome measures of HGSC, including PFS, OS, and platinum chemoresistance. Accurate and cost-effective predictive biomarkers of platinum chemotherapy resistance are needed to identify patients most likely to benefit from standard treatments, and TSP can easily be implemented and integrated into prospective clinical trial design and adapted to identify patients who are least likely to benefit long-term from conventional platinum-based cytotoxic chemotherapy treatment at the time of initial diagnosis.

The high-grade serous ovarian cancer metastasis and chemoresistance in 3D models

High-grade serous ovarian cancer (HGSOC) is the most frequent and aggressive type of epithelial ovarian cancer, with high recurrence rate and chemoresistance being the main issues in its clinical management. HGSOC is specifically challenging due to the metastatic dissemination via spheroids in the ascitic fluid. The HGSOC spheroids represent the invasive and chemoresistant cellular fraction, which is impossible to investigate in conventional two-dimensional (2D) monolayer cell cultures lacking critical cell-to-cell and cell-extracellular matrix interactions. Three-dimensional (3D) HGSOC cultures, where cells aggregate and exhibit relevant interactions, offer a promising in vitro model of peritoneal metastasis and multicellular drug resistance. This review summarizes recent studies of HGSOC in 3D culture conditions and highlights the role of multicellular HGSOC spheroids and ascitic environment in HGSOC metastasis and chemoresistance.

Computational Image and Molecular Analysis Reveal Unique Prognostic Features of Immune Architecture in African Versus European American Women with Endometrial Cancer

Endometrial cancer (EC) disproportionately affects African American (AA) women in terms of progression and death. In our study, we sought to employ computerized image and bioinformatic analysis to tease out morphologic and molecular differences in EC between AA and European-American (EA) populations. We identified the differences in immune cell spatial patterns between AA and EA populations with markers of tumor biology, including histologic and molecular subtypes. The models performed best when they were trained and validated using data from the same population. Unsupervised clustering revealed a distinct association between immune cell features and known molecular subtypes of endometrial cancer that varied between AA and EA populations. Our genomic analysis revealed two distinct and novel gene sets with mutations associated with improved prognosis in AA and EA patients. Our study findings suggest the need for population-specific risk prediction models for women with endometrial cancer.

Significance of Tumor-Stroma Ratio (TSR) in Predicting Outcomes of Malignant Tumors

Background and Objectives: The present study aimed to elucidate the distribution and the prognostic implications of tumor-stroma ratio (TSR) in various malignant tumors through a meta-analysis. Materials and Methods: This meta-analysis included 51 eligible studies with information for overall survival (OS) or disease-free survival (DFS), according to TSR. In addition, subgroup analysis was performed based on criteria for high TSR. Results: The estimated rate of high TSR was 0.605 (95% confidence interval (CI) 0.565-0.644) in overall malignant tumors. The rates of high TSR ranged from 0.276 to 0.865. The highest rate of high TSR was found in endometrial cancer (0.865, 95% CI 0.827-0.895). The estimated high TSR rates of colorectal, esophageal, and stomach cancers were 0.622, 0.529, and 0.448, respectively. In overall cases, patients with high TSR had better OS and DFS than those with low TSR (hazard ratio (HR) 0.631, 95% CI 0.542-0.734, and HR 0.564, 95% CI 0.0.476-0.669, respectively). Significant correlations with OS were found in the breast, cervical, colorectal, esophagus, head and neck, ovary, stomach, and urinary tract cancers. In addition, there were significant correlations of DFS in breast, cervical, colorectal, esophageal, larynx, lung, and stomach cancers. In endometrial cancers, high TSR was significantly correlated with worse OS and DFS. Conclusions: The rate of high TSR was different in various malignant tumors. TSR can be useful for predicting prognosis through a routine microscopic examination of malignant tumors.

Clinical Significance of the Stromatic Component in Ovarian Cancer: Quantity Over Quality in Outcome Prediction

Background

The tumor stroma is composed of a complex network of non-cancerous cells and extracellular matrix elements that collectively are crucial for cancer progression and treatment response. Within the realm of ovarian cancer, the expression of the stromal gene cluster has been linked to poorer progression-free and overall survival rates. However, in the age of precision medicine and genome sequencing, the notion that the simple measurement of tumor-stroma proportion alone can serve as a biomarker for clinical outcome is a topic that continues to generate controversy and provoke discussion. Our current study reveals that it is the quantity of stroma, rather than its quality, that serves as a clinically significant indicator of patient outcome in ovarian cancer.

Methods

This study leveraged the High-Grade-Serous-Carcinoma (HGSC) cohort of the publicly accessible Cancer Genome Atlas Program (TCGA) along with an independent cohort comprising HGSC clinical specimens in diagnostic and Tissue Microarray formats. Our objective was to investigate the correlation between the Tumor-Stroma-Proportion (TSP) and progression-free survival (PFS), overall survival (OS), and response to chemotherapy. We assessed these associations using H&E-stained slides and tissue microarrays. Our analysis employed semi-parametric models that accounted for age, metastases, and residual disease as controlling factors.

Results

We found that high TSP (>50% stroma) was associated with significantly shorter progression-free survival (PFS) (p=0.016) and overall survival (OS) (p=0.006). Tumors from patients with chemoresistant tumors were twice as likely to have high TSP as compared to tumors from chemosensitive patients (p=0.012). In tissue microarrays, high TSP was again associated with significantly shorter PFS (p=0.044) and OS (p=0.0001), further confirming our findings. The Area Under the ROC curve for the model predicting platinum was estimated at 0.7644.

Conclusions

In HGSC, TSP was a consistent and reproducible marker of clinical outcome measures, including PFS, OS, and platinum chemoresistance. Assessment of TSP as a predictive biomarker that can be easily implemented and integrated into prospective clinical trial design and adapted to identify, at time of initial diagnosis, patients who are least likely to benefit long-term from conventional platinum-based cytotoxic chemotherapy treatment.

Molecular cluster mining of high-grade serous ovarian cancer via multi-omics data analysis aids precise medicine

PURPOSE

HGSOC is a kind of gynecological cancer with high mortality and strong heterogeneity. The study used multi-omics and multiple algorithms to identify novel molecular subtypes, which can help patients obtain more personalized treatments.

METHODS

Firstly, the consensus clustering result was obtained using a consensus ensemble of ten classical clustering algorithms, based on mRNA, lncRNA, DNA methylation, and mutation data. The difference in signaling pathways was evaluated using the single-sample gene set enrichment analysis (ssGSEA). Meanwhile, the relationship between genetic alteration, response to immunotherapy, drug sensitivity, prognosis, and subtypes was further analyzed. Finally, the reliability of the new subtype was verified in three external datasets.

RESULTS

Three molecular subtypes were identified. Immune desert subtype (CS1) had little enrichment in the immune microenvironment and metabolic pathways. Immune/non-stromal subtype (CS2) was enriched in the immune microenvironment and metabolism of polyamines. Immune/stromal subtype (CS3) not only enriched anti-tumor immune microenvironment characteristics but also enriched pro-tumor stroma characteristics, glycosaminoglycan metabolism, and sphingolipid metabolism. The CS2 had the best overall survival and the highest response rate to immunotherapy. The CS3 had the worst prognosis and the lowest response rate to immunotherapy but was more sensitive to PARP and VEGFR molecular-targeted therapy. The similar differences among three subtypes were successfully validated in three external cohorts.

CONCLUSION

We used ten clustering algorithms to comprehensively analyze four types of omics data, identified three biologically significant subtypes of HGSOC patients, and provided personalized treatment recommendations for each subtype. Our findings provided novel views into the HGSOC subtypes and could provide potential clinical treatment strategies.

Photochemical Targeting of Mitochondria to Overcome Chemoresistance in Ovarian Cancer †

Ovarian cancer is the most lethal gynecologic malignancy with a stubborn mortality rate of ~65%. The persistent failure of multiline chemotherapy, and significant tumor heterogeneity, has made it challenging to improve outcomes. A target of increasing interest is the mitochondrion because of its essential role in critical cellular functions, and the significance of metabolic adaptation in chemoresistance. This review describes mitochondrial processes, including metabolic reprogramming, mitochondrial transfer and mitochondrial dynamics in ovarian cancer progression and chemoresistance. The effect of malignant ascites, or excess peritoneal fluid, on mitochondrial function is discussed. The role of photodynamic therapy (PDT) in overcoming mitochondria-mediated resistance is presented. PDT, a photochemistry-based modality, involves the light-based activation of a photosensitizer leading to the production of short-lived reactive molecular species and spatiotemporally confined photodamage to nearby organelles and biological targets. The consequential effects range from subcytotoxic priming of target cells for increased sensitivity to subsequent treatments, such as chemotherapy, to direct cell killing. This review discusses how PDT-based approaches can address key limitations of current treatments. Specifically, an overview of the mechanisms by which PDT alters mitochondrial function, and a summary of preclinical advancements and clinical PDT experience in ovarian cancer are provided.

Standardization of the tumor-stroma ratio scoring method for breast cancer research

Purpose

The tumor-stroma ratio (TSR) has repeatedly proven to be correlated with patient outcomes in breast cancer using large retrospective cohorts. However, studies validating the TSR often show variability in methodology, thereby hampering comparisons and uniform outcomes.

Method

This paper provides a detailed description of a simple and uniform TSR scoring method using Hematoxylin and Eosin (H&E)-stained core biopsies and resection tissue, specifically focused on breast cancer. Possible histological challenges that can be encountered during scoring including suggestions to overcome them are reported. Moreover, the procedure for TSR estimation in lymph nodes, scoring on digital images and the automatic assessment of the TSR using artificial intelligence are described.

Conclusion

Digitized scoring of tumor biopsies and resection material offers interesting future perspectives to determine patient prognosis and response to therapy. The fact that the TSR method is relatively easy, quick, and cheap, offers great potential for its implementation in routine diagnostics, but this requires high quality validation studies.

Assessing Histology Structures by Ex Vivo MR Microscopy and Exploring the Link Between MRM-Derived Radiomic Features and Histopathology in Ovarian Cancer

The value of MR radiomic features at a microscopic scale has not been explored in ovarian cancer. The objective of this study was to probe the associations of MR microscopy (MRM) images and MRM-derived radiomic maps with histopathology in high-grade serous ovarian cancer (HGSOC). Nine peritoneal implants from 9 patients with HGSOC were imaged ex vivo with MRM using a 9.4-T MR scanner. All MRM images and computed pixel-wise radiomics maps were correlated with the slice-matched stroma and tumor proportion maps derived from whole histopathologic slide images (WHSI) of corresponding peritoneal implants. Automated MRM-derived segmentation maps of tumor and stroma were constructed using holdout test data and validated against the histopathologic gold standard. Excellent correlation between MRM images and WHSI was observed (Dice index = 0.77). Entropy, correlation, difference entropy, and sum entropy radiomic features were positively associated with high stromal proportion (r = 0.97,0.88, 0.81, and 0.96 respectively, p < 0.05). MR signal intensity, energy, homogeneity, auto correlation, difference variance, and sum average were negatively associated with low stromal proportion (r = -0.91, -0.93, -0.94, -0.9, -0.89, -0.89, respectively, p < 0.05). Using the automated model, MRM predicted stromal proportion with an accuracy ranging from 61.4% to 71.9%. In this hypothesis-generating study, we showed that it is feasible to resolve histologic structures in HGSOC using ex vivo MRM at 9.4 T and radiomics.

Utilizing digital pathology to quantify stromal caveolin-1 expression in malignant and benign ovarian tumors: Associations with clinicopathological parameters and clinical outcomes

Loss of stromal caveolin-1 (Cav-1) is a biomarker of a cancer-associated fibroblast (CAF) phenotype and is related to progression, metastasis, and poor outcomes in several cancers. The objective of this study was to evaluate the clinical significance of Cav-1 expression in invasive epithelial ovarian cancer (OvCa). Epithelial and stromal Cav-1 expression were quantified in serous OvCa and benign ovarian tissue in two, independent cohorts–one quantified expression using immunohistochemistry (IHC) and the other using multiplex immunofluorescence (IF) with digital image analysis designed to target CAF-specific expression. Cav-1 expression was significantly downregulated in OvCa stroma compared to non-neoplastic stroma using both the IHC (p = 0.002) and IF (p = 1.8x10^-13) assays. OvCa stroma showed Cav-1 downregulation compared to tumor epithelium with IHC (p = 1.2x10^-24). Conversely, Cav-1 expression was higher in OvCa stroma compared to tumor epithelium with IF (p = 0.002). There was moderate correlation between IHC and IF methods for stromal Cav-1 expression (r² = 0.69, p = 0.006) whereas there was no correlation for epithelial expression (r² = 0.006, p = 0.98). Irrespective of the staining assay, neither response to therapy or overall survival correlated with the expression level of Cav-1 in the stroma or tumor epithelium. Our findings demonstrate a loss of stromal Cav-1 expression in ovarian serous carcinomas. Studies are needed to replicate these findings and explore therapeutic implications, particularly for immunotherapy response.

Downregulation of LINC01508 contributes to cisplatin resistance in ovarian cancer via the regulation of the Hippo-YAP pathway

BACKGROUND

Some long non-coding RNAs (lncRNAs) have been found to contribute to cisplatin resistance. Here, we identified a novel lncRNA that was downregulated in cisplatin-resistant to ovarian cancer (OC) cells and aimed to examine the contribution of LINC01508 to cisplatin resistance in OC cells.

METHODS

Differences in the lncRNA expression profile between OV2008 and C13K cells were assessed by lncRNA expression microarray. The expression of LINC01508 in ovarian epithelial cells, four OC cells, and OC, benign ovary tumor and normal ovary, cisplatin-resistant and non-resistant OC specimens were evaluated by quantitative real-time polymerase chain reaction (qPCR). The role of LINC01508 in OC cisplatin-resistant was evaluated by cell counting kit-8 (CCK-8), flow cytometry, colony formation, wound healing, Transwell, and tumor growth inhibition study in vivo. The clinical associations of LINC01508 in OC were evaluated using correlation analysis. The effects of verteporfin (VP) on cisplatin were explored to reveal the function of the hippo-YAP pathway on the cisplatin tolerance of C13K.

RESULTS

LINC01508 was downregulated in cisplatin-resistant OC cells and platinum-resistant OC tissue (p<0.01). LINC01508 downregulation was correlated with tumor size, residual tumor, and platinum resistance. The overexpression of LINC01508 improves in vitro and in vivo sensitivity to cisplatin while predicts the poor overall survival which need further follow-up research. The increased level of LINC01508 could suppress the cisplatin resistance of OC cells through the inhibition of the hippo-YAP pathway.

CONCLUSIONS

The study proposes that dysregulation of LINC01508 expression results in resistance of OC to cisplatin through the inhibition of the hippo-YAP pathway.

Extensive three-dimensional intratumor proteomic heterogeneity revealed by multiregion sampling in high-grade serous ovarian tumor specimens

Enriched tumor epithelium, tumor-associated stroma, and whole tissue were collected by laser microdissection from thin sections across spatially separated levels of ten high-grade serous ovarian carcinomas (HGSOCs) and analyzed by mass spectrometry, reverse phase protein arrays, and RNA sequencing. Unsupervised analyses of protein abundance data revealed independent clustering of an enriched stroma and enriched tumor epithelium, with whole tumor tissue clustering driven by overall tumor "purity." Comparing these data to previously defined prognostic HGSOC molecular subtypes revealed protein and transcript expression from tumor epithelium correlated with the differentiated subtype, whereas stromal proteins (and transcripts) correlated with the mesenchymal subtype. Protein and transcript abundance in the tumor epithelium and stroma exhibited decreased correlation in samples collected just hundreds of microns apart. These data reveal substantial tumor microenvironment protein heterogeneity that directly bears on prognostic signatures, biomarker discovery, and cancer pathophysiology and underscore the need to enrich cellular subpopulations for expression profiling.

Sphingolipids as multifaceted mediators in ovarian cancer

Ovarian cancer is the most lethal gynaecological malignancy. It is commonly diagnosed at advanced stage when it has metastasised to the abdominal cavity and treatment becomes very challenging. While current standard therapy involving debulking surgery and platinum + taxane-based chemotherapy is associated with high response rates initially, the large majority of patients relapse and ultimately succumb to chemotherapy-resistant disease. In order to improve survival novel strategies for early detection and therapeutics against treatment-refractory disease are urgently needed. A promising new target against ovarian cancer is the sphingolipid pathway which is commonly hijacked in cancer to support cell proliferation and survival and has been shown to promote chemoresistance and metastasis in a wide range of malignant neoplasms. In particular, the sphingosine kinase 1-sphingosine 1-phosphate receptor 1 axis has been shown to be altered in ovarian cancer in multiple ways and therefore represents an attractive therapeutic target. Here we review the roles of sphingolipids in ovarian cancer progression, metastasis and chemoresistance, highlighting novel strategies to target this pathway that represent potential avenues to improve patient survival.

Multiparametric MRI-based radiomics signature for preoperative estimation of tumor-stroma ratio in rectal cancer

OBJECTIVE

To determine whether a radiomics signature (rad-score) outperforms ADC in TSR estimation by developing a radiomics biomarker for preoperative TSR diagnosis in rectal cancer.

METHODS

This study included 149 patients (119 and 30 in the training and validation cohorts, respectively). All patients underwent T2-weighted, diffusion-weighted, and contrast-enhanced T1-weighted imaging. A rad-score was generated using the least absolute shrinkage and selection operator (LASSO) algorithm and stepwise multivariate logistic regression. Meanwhile, the mean ADCs were calculated from ADC maps. For both the mean ADC and rad-score, binary logistic regression and Spearman correlation coefficients were used to determine associations with the TSR, and the area under the receiver operating characteristic (ROC) curve was used to assess the diagnostic performance. The reliability of the rad-score was quantified by comparing the imaging-estimated TSR with the actual TSR of each patient.

RESULTS

Both the mean ADC and rad-score were positively correlated with the TSR in the training cohort (mean ADC: p < 0.001, r = 0.566; rad-score: p < 0.001, r = 0.559) and validation cohort (mean ADC: p < 0.001, r = 0.671; rad-score: p = 0.002, r = 0.536). The rad-score, with AUCs of 0.917 (95% CI 0.869-0.965) and 0.787 (95% CI 0.602-0.972) in the training and validation cohorts, respectively, outperformed the mean ADC (training cohort: AUC = 0.776, 95% CI 0.693-0.859; validation cohort: AUC = 0.764, 95% CI 0.592-0.936) in TSR estimation.

CONCLUSION

The ADC possesses potential diagnostic value for TSR estimation in rectal cancer, and the rad-score shows increased diagnostic value over the ADC and may be a promising supplemental tool for patient stratification and informing decision-making.

KEY POINTS

• Tumor-stroma ratio has been verified as an independent prognostic factor for various solid tumors including rectal cancer. • The ADC and multiparametric MRI-based radiomics features were significantly and positively correlated with the tumor-stroma ratio in rectal cancer. • The radiomics signature outperformed the ADC in discriminating TSR in rectal cancer.

Immunotherapy for Ovarian Cancer: Adjuvant, Combination, and Neoadjuvant

Ovarian cancer is the most lethal gynecologic malignancy. Surgery and chemotherapy are the primary treatments for ovarian cancer; however, patients often succumb to recurrence with chemotherapeutic resistance within several years after the initial treatment. In the past two decades, immunotherapy has rapidly developed, and has revolutionized the treatment of various types of cancer. Despite the fact that immunotherapy response rates among ovarian cancer patients remain modest, treatment with immune checkpoint inhibitors (ICIs), chimeric antigen receptor (CAR)- and TCR-engineered T cells is rapidly developing. Therapeutic efficiency could be improved significantly if immunotherapy is included as an adjuvant therapy, in combination with chemotherapy, radiation therapy, and the use of anti-angiogenesis drugs, and poly ADP ribose polymerase inhibitors (PARPi). Newly developed technologies that identify therapeutic targets, predict treatment efficacy, rapidly screen potential immunotherapy drugs, provide neoadjuvant immunotherapy, and utilize nanomedicine technology provide new opportunities for the treatment of ovarian cancer, and have the potential to prolong patient survival. However, important issues that may hinder the efficacy of such approaches, including hyperprogressive disease (HPD), immunotherapy-resistance, and toxicity of the treatments, including neurotoxicity, must be taken into account and addressed for these therapies to be effective.

Expression of long noncoding RNAs in cancer-associated fibroblasts linked to patient survival in ovarian cancer

Cancer-associated fibroblasts (CAFs) are the most abundant cell type in the tumor microenvironment and are responsible for producing the desmoplastic reaction that is a poor prognostic factor in ovarian cancer. Long non-coding RNAs (lncRNAs) have been shown to play important roles in cancer. However, very little is known about the role of lncRNAs in the tumor microenvironment. We aimed to identify lncRNAs expressed in ovarian CAFs that were associated with patient survival and used computational approaches to predict their function. Increased expression of 9 lncRNAs and decreased expression of 1 lncRNA in ovarian CAFs were found to be associated with poorer overall survival. A "guilt-by-association" approach was used to predict the function of these lncRNAs. In particular, MIR155HG was predicted to play a role in immune response. Further investigation revealed high MIR155HG expression to be associated with higher infiltrates of immune cell subsets. In conclusion, these data indicate expression on several lncRNAs in CAFs are associated with patient survival and are likely to play an important role in regulating CAF function.

The Role of Stroma in Ovarian Cancer

Background: Ovarian cancer is one of the gynecological malignancies responsible for thousands of deaths in women worldwide. Malignant solid tumors are formed by malignant cells and stroma that influence each other, where different types of cells in the stromal environment can be recruited by malignant cells to promote tumor growth and facilitate metastasis. The chronic inflammatory response is increasingly accepted in its relation to the pathophysiology of the onset and development of tumors, sustained cell proliferation in an environment rich in inflammatory cells, growth factors, activated stroma and DNA damage agents may increase the risk to develop a neoplasm.Methods: A search for the following keywords was performed in the PubMed database; "Ovarian cancer", "stroma", "tumor-associated macrophages", "cancer-associated fibroblasts", "cytokines", "angiogenesis", "epithelial-mesenchymal transition", and "extracellular matrix".Results: The articles identified were published in English between 1971 and 2018. A total of 154 articles were selected for further analysis. Conclusion: We consider ovarian cancer as a heterogeneous disease, not only in the sense that different histological or molecular subtypes may be behind the same clinical result, but also that multiple cell types besides cancer cells, like other non-cellular components, need to be mobilized and coordinated to support tumor survival, growth, invasion and progression.

Discovery and Validation of Novel Biomarkers for Detection of Epithelial Ovarian Cancer

Detection of epithelial ovarian cancer (EOC) poses a critical medical challenge. However, novel biomarkers for diagnosis remain to be discovered. Therefore, innovative approaches are of the utmost importance for patient outcome. Here, we present a concept for blood-based biomarker discovery, investigating both epithelial and specifically stromal compartments, which have been neglected in search for novel candidates. We queried gene expression profiles of EOC including microdissected epithelium and adjacent stroma from benign and malignant tumours. Genes significantly differentially expressed within either the epithelial or the stromal compartments were retrieved. The expression of genes whose products are secreted yet absent in the blood of healthy donors were validated in tissue and blood from patients with pelvic mass by NanoString analysis. Results were confirmed by the comprehensive gene expression database, CSIOVDB (Ovarian cancer database of Cancer Science Institute Singapore). The top 25% of candidate genes were explored for their biomarker potential, and twelve were able to discriminate between benign and malignant tumours on transcript levels (p < 0.05). Among them T-cell differentiation protein myelin and lymphocyte (MAL), aurora kinase A (AURKA), stroma-derived candidates versican (VCAN), and syndecan-3 (SDC), which performed significantly better than the recently reported biomarker fibroblast growth factor 18 (FGF18) to discern malignant from benign conditions. Furthermore, elevated MAL and AURKA expression levels correlated significantly with a poor prognosis. We identified promising novel candidates and found the stroma of EOC to be a suitable compartment for biomarker discovery.

Regional perturbation of gene transcription is associated with intrachromosomal rearrangements and gene fusion transcripts in high grade ovarian cancer

Genomic rearrangements are a hallmark of cancer biology and progression, allowing cells to rapidly transform through alterations in regulatory structures, changes in expression patterns, reprogramming of signaling pathways, and creation of novel transcripts via gene fusion events. Though functional gene fusions encoding oncogenic proteins are the most dramatic outcomes of genomic rearrangements, we investigated the relationship between rearrangements evidenced by fusion transcripts and local expression changes in cancer using transcriptome data alone. 9,953 gene fusion predictions from 418 primary serious ovarian cancer tumors were analyzed, identifying depletions of gene fusion breakpoints within coding regions of fused genes as well as an N-terminal enrichment of breakpoints within fused genes. We identified 48 genes with significant fusion-associated upregulation and furthermore demonstrate that significant regional overexpression of intact genes in patient transcriptomes occurs within 1 megabase of 78 novel gene fusions that function as central markers of these regions. We reveal that cancer transcriptomes select for gene fusions that preserve protein and protein domain coding potential. The association of gene fusion transcripts with neighboring gene overexpression supports rearrangements as mechanism through which cancer cells remodel their transcriptomes and identifies a new way to utilize gene fusions as indicators of regional expression changes in diseased cells with only transcriptomic data.

Cancer-associated stroma significantly contributes to the mesenchymal subtype signature of serous ovarian cancer

OBJECTIVE

Mesenchymal (MES) subtype of high-grade serous ovarian cancer (HGSOC) is associated with worse outcomes including survival and resectability compared with other molecular subtypes. Molecular subtypes have historically been derived from 'tumor', consisting of both cancer and stromal cells. We sought to determine the origins of multiple MES subtype gene signatures in HGSOC.

METHODS

Fifteen patients with MES subtype of HGSOC diagnosed between 2010 and 2013 were identified. Formalin-fixed paraffin-embedded (FFPE) blocks from primary surgery were sectioned for immunohistochemistry (IHC) staining of relevant proteins. Eight genes (ACTA2, COL5A1, COL11A1, FAP, POSTN, VCAN, ZEB1 and p-SMAD2) were selected for IHC staining based on their differential expression in MES vs. non-MES subtypes of HGSOC. Slides were scored for intensity and localization and simple statistics were used to compare expression results in cancer vs. stroma and between primary and metastatic sites.

RESULTS

COL5A1, VCAN, FAP, and ZEB1 proteins were almost exclusively expressed by stroma as opposed to cancer cells. In addition, stromal expression was dominant for ACTA2, COL11A1, POSTN and p-SMAD2. In general there were minimal differences in expression of proteins between primary and metastatic sites, exceptions being COL5A1 (reduced in metastases) and COL11A1 (increased in metastases). Nuclear p-SMAD2 expression was more common in metastatic stroma.

CONCLUSIONS

The existing molecular classification of HGSOC MES subtype reflects a significant stromal contribution, suggesting an important role in HGSOC behavior and thus stroma may be a relevant therapeutic target. Specific patterns of expression indicate that collagens and TGF-β signaling are involved in the metastatic process.

Epigenetic Crosstalk between the Tumor Microenvironment and Ovarian Cancer Cells: A Therapeutic Road Less Traveled

Metastatic dissemination of epithelial ovarian cancer (EOC) predominantly occurs through direct cell shedding from the primary tumor into the intra-abdominal cavity that is filled with malignant ascitic effusions. Facilitated by the fluid flow, cells distribute throughout the cavity, broadly seed and invade through peritoneal lining, and resume secondary tumor growth in abdominal and pelvic organs. At all steps of this unique metastatic process, cancer cells exist within a multidimensional tumor microenvironment consisting of intraperitoneally residing cancer-reprogramed fibroblasts, adipose, immune, mesenchymal stem, mesothelial, and vascular cells that exert miscellaneous bioactive molecules into malignant ascites and contribute to EOC progression and metastasis via distinct molecular mechanisms and epigenetic dysregulation. This review outlines basic epigenetic mechanisms, including DNA methylation, histone modifications, chromatin remodeling, and non-coding RNA regulators, and summarizes current knowledge on reciprocal interactions between each participant of the EOC cellular milieu and tumor cells in the context of aberrant epigenetic crosstalk. Promising research directions and potential therapeutic strategies that may encompass epigenetic tailoring as a component of complex EOC treatment are discussed.

The Tumor Microenvironment of Epithelial Ovarian Cancer and Its Influence on Response to Immunotherapy

Immunotherapy as a treatment for cancer is a growing field of endeavor but reports of success have been limited for epithelial ovarian cancer. Overcoming the challenges to developing more effective therapeutic approaches lies in a better understanding of the factors in cancer cells and the surrounding tumor microenvironment that limit response to immunotherapies. This article provides an overview of some ovarian cancer cell features such as tumor-associated antigens, ovarian cancer-derived exosomes, tumor mutational burden and overexpression of immunoinhibitory molecules. Moreover, we describe relevant cell types found in epithelial ovarian tumors including immune cells (T and B lymphocytes, Tregs, NK cells, TAMs, MDSCs) and other components found in the tumor microenvironment including fibroblasts and the adipocytes in the omentum. We focus on how those components may influence responses to standard treatments or immunotherapies.

The Tumor Microenvironment of Epithelial Ovarian Cancer and Its Influence on Response to Immunotherapy

Immunotherapy as a treatment for cancer is a growing field of endeavor but reports of success have been limited for epithelial ovarian cancer. Overcoming the challenges to developing more effective therapeutic approaches lies in a better understanding of the factors in cancer cells and the surrounding tumor microenvironment that limit response to immunotherapies. This article provides an overview of some ovarian cancer cell features such as tumor-associated antigens, ovarian cancer-derived exosomes, tumor mutational burden and overexpression of immunoinhibitory molecules. Moreover, we describe relevant cell types found in epithelial ovarian tumors including immune cells (T and B lymphocytes, Tregs, NK cells, TAMs, MDSCs) and other components found in the tumor microenvironment including fibroblasts and the adipocytes in the omentum. We focus on how those components may influence responses to standard treatments or immunotherapies.

The Tumor Microenvironment of Epithelial Ovarian Cancer and Its Influence on Response to Immunotherapy

Immunotherapy as a treatment for cancer is a growing field of endeavor but reports of success have been limited for epithelial ovarian cancer. Overcoming the challenges to developing more effective therapeutic approaches lies in a better understanding of the factors in cancer cells and the surrounding tumor microenvironment that limit response to immunotherapies. This article provides an overview of some ovarian cancer cell features such as tumor-associated antigens, ovarian cancer-derived exosomes, tumor mutational burden and overexpression of immunoinhibitory molecules. Moreover, we describe relevant cell types found in epithelial ovarian tumors including immune cells (T and B lymphocytes, Tregs, NK cells, TAMs, MDSCs) and other components found in the tumor microenvironment including fibroblasts and the adipocytes in the omentum. We focus on how those components may influence responses to standard treatments or immunotherapies.

Heterocellular 3D scaffolds as biomimetic to recapitulate the tumor microenvironment of peritoneal metastases in vitro and in vivo

Peritoneal metastasis is a major cause of death and preclinical models are urgently needed to enhance therapeutic progress. This study reports on a hybrid hydrogel-polylactic acid (PLA) scaffold that mimics the architecture of peritoneal metastases at the qualitative, quantitative and spatial level. Porous PLA scaffolds with controllable pore size, geometry and surface properties are functionalized by type I collagen hydrogel. Co-seeding of cancer-associated fibroblasts (CAF) increases cancer cell adhesion, recovery and exponential growth by in situ heterocellular spheroid formation. Scaffold implantation into the peritoneum allows long-term follow-up (>14 weeks) and results in a time-dependent increase in vascularization, which correlates with cancer cell colonization in vivo. CAF, endothelial cells, macrophages and cancer cells show spatial and quantitative aspects as similarly observed in patient-derived peritoneal metastases. CAF provide long-term secretion of complementary paracrine factors implicated in spheroid formation in vitro as well as in recruitment and organization of host cells in vivo. In conclusion, the multifaceted heterocellular interactions that occur within peritoneal metastases are reproduced in this tissue-engineered implantable scaffold model.

The metabolic cross-talk between epithelial cancer cells and stromal fibroblasts in ovarian cancer progression: Autophagy plays a role

Cancer and stromal cells, which include (cancer‐associated) fibroblasts, adipocytes, and immune cells, constitute a mixed cellular ecosystem that dynamically influences the behavior of each component, creating conditions that ultimately favor the emergence of malignant clones. Ovarian cancer cells release cytokines that recruit and activate stromal fibroblasts and immune cells, so perpetuating a state of inflammation in the stroma that hampers the immune response and facilitates cancer survival and propagation. Further, the stroma vasculature impacts the metabolism of the cells by providing or limiting the availability of oxygen and nutrients. Autophagy, a lysosomal catabolic process with homeostatic and prosurvival functions, influences the behavior of cancer cells, affecting a variety of processes such as the survival in metabolic harsh conditions, the invasive growth, the development of immune and chemo resistance, the maintenance of stem‐like properties, and dormancy. Further, autophagy is involved in the secretion and the signaling of promigratory cytokines. Cancer‐associated fibroblasts can influence the actual level of autophagy in ovarian cancer cells through the secretion of pro‐inflammatory cytokines and the release of autophagy‐derived metabolites and substrates. Interrupting the metabolic cross‐talk between cancer cells and cancer‐associated fibroblasts could be an effective therapeutic strategy to arrest the progression and prevent the relapse of ovarian cancer.

Revisiting ovarian cancer microenvironment: a friend or a foe?

Development of ovarian cancer involves the co-evolution of neoplastic cells together with the adjacent microenvironment. Steps of malignant progression including primary tumor outgrowth, therapeutic resistance, and distant metastasis are not determined solely by genetic alterations in ovarian cancer cells, but considerably shaped by the fitness advantage conferred by benign components in the ovarian stroma. As the dynamic cancer topography varies drastically during disease progression, heterologous cell types within the tumor microenvironment (TME) can actively determine the pathological track of ovarian cancer. Resembling many other solid tumor types, ovarian malignancy is nurtured by a TME whose dark side may have been overlooked, rather than overestimated. Further, harnessing breakthrough and targeting cures in human ovarian cancer requires insightful understanding of the merits and drawbacks of current treatment modalities, which mainly target transformed cells. Thus, designing novel and precise strategies that both eliminate cancer cells and manipulate the TME is increasingly recognized as a rational avenue to improve therapeutic outcome and prevent disease deterioration of ovarian cancer patients.

Tumor-Stroma Ratio is an independent predictor for overall survival and disease free survival in gastric cancer patients

BACKGROUND

Despite different prognostic factors have been already studied, patients undergoing potentially curative resection for gastric cancer, still have a poor outcome. There is therefore the need to identify novel prognostic factors. Recently, Tumor-Stroma Ratio (TSR) was proven to be associated with prognosis in different types of cancers. Aim of this study was to evaluate the prognostic value of TSR in gastric cancer patients.

METHODS

106 patients underwent gastrectomy between January 2004 and December 2015. Demographics and histopathological characteristics were collected. We considered a 50% TSR cutoff value to divide patients in Stroma-Rich (≥50%) and Stroma-Poor (<50%) groups.

RESULTS

Forty-one (38.7%) patients were classified as Stroma-Poor while 65 (61.3%) as Stroma-Rich (61.3%). The Stroma-Rich patients had a higher number of positive lymph-nodes, lymph node ratio (LNR), a higher percentage of T3/T4 local invasion and N2/N3, and a more advanced TNM. Moreover, these patients showed a higher percentage of lymphovascular and perineural invasion. With a median FU of 38 months Stroma-Rich patients had a significantly worse 5-years actuarial overall survival (OS) and disease free survival (DFS) compared to Stroma-Poor patients. Moreover, the multivariate analysis showed that Stroma-Rich was the only independent factor associated with OS and DFS together with TNM-Stage.

CONCLUSIONS

TSR is an independent marker of poor prognosis in patients with gastric cancer that should be readily incorporated into routine clinical pathology reporting. Identification of sensitive markers for patients who had undergone curative gastrectomy and who are at high risk of recurrence could provide useful information for planning follow-up after surgery or intensive and or/targeting adjuvant chemotherapy.

Distinct Patterns of Stromal and Tumor Expression of ROR1 and ROR2 in Histological Subtypes of Epithelial Ovarian Cancer

OBJECTIVE

The ROR1 and ROR2 receptor tyrosine kinases have both been implicated in ovarian cancer progression and have been shown to drive migration and invasion. There is an increasing importance of the role of stroma in ovarian cancer metastasis; however, neither ROR1 nor ROR2 expression in tumor or stromal cells has been analyzed in the same clinical cohort.

AIM

To determine ROR1 and ROR2 expression in ovarian cancer and surrounding microenvironment and examine associations with clinicopathological characteristics.

METHODS

Immunohistochemistry for ROR1 and ROR2 was used to assess receptor expression in a cohort of epithelial ovarian cancer patients (n=178). Results were analyzed in relation to clinical and histopathological characteristics and survival. Matched patient sample case studies of normal, primary, and metastatic lesions were used to examine ROR expression in relation to ovarian cancer progression.

RESULTS

ROR1 and ROR2 are abnormally expressed in malignant ovarian epithelium and stroma. Higher ROR2 tumor expression was found in early-stage, low-grade endometrioid carcinomas. ROR2 stromal expression was highest in the serous subtype. In matched patient case studies, metastatic samples had higher expression of ROR2 in the stroma, and a recurrent sample had the highest expression of ROR2 in both tumor and stroma.

CONCLUSION

ROR1 and ROR2 are expressed in tumor-associated stroma in all histological subtypes of ovarian cancer and hold potential as therapeutic targets which may disrupt tumor and stroma interactions.

Tenascin-C is a potential cancer-associated fibroblasts marker and predicts poor prognosis in prostate cancer

Tenascin-C (TNC), as a member of the extracellular matrix (ECM), plays an important role in cancer cell proliferation and migration and tumor invasion in various types of cancer. Here, we attempted to investigate the role of TNC as a prognostic factor in prostate cancer. We studied TNC expression via immunohistochemistry in 145 prostate cancer tissue samples. The clinicopathological relevance of TNC expression was examined, as well as other cancer-associated fibroblasts (CAFs)-related factors. Our results showed that the high levels of TNC expression in prostate cancer stroma was significantly associated with lymph node metastasis (P = 0.024) and clinical stage (P = 0.032). Furthermore, TNC was positively correlated with increased micro-vessel density (MVD) (P = 0.017) and tumor associated macrophage (TAM) population (P = 0.025). In both univariate and multivariate Cox regression analyses, TNC (P < 0.001) was an independent poor prognostic factor for overall survival in prostate cancer patients. Moreover, over-expression of TNC (P < 0.001), SMA (P = 0.042) and vimentin (P = 0.010) were significantly correlated with the lower overall survival. In addition, TNC expression in prostate cancer stroma was significantly associated with FSP1 (P = 0.011), SMA (P = 0.021), and vimentin (P = 0.002). In conclusion, our study revealed that high level of TNC as a potential biomarker of CAFs was significantly correlated with the poor prognosis for prostate cancer patients.

Histochemical and Immunohistochemical Study of α-SMA, Collagen, and PCNA in Epithelial Ovarian Neoplasm

Background:

Alpha-smooth muscle actin (α-SMA) is an isoform of actin, positive in myofibroblasts and is an epithelial to mesenchymal transition (EMT) marker. EMT is a process by which tumor cells develop to be more hostile and able to metastasize. Progression of tumor cells is always followed by cell composition and extracellular matrix component alteration. Increased α-SMA expression and collagen alteration may predict the progressivity of ovarian neoplasms.

Objective:

The aim of this research was to analyse the characteristic of α-SMA and collagen in tumor cells and stroma of ovarian neoplasms. In this study, PCNA (proliferating cell nuclear antigen) expression was also investigated.

Methods:

Thirty samples were collected including serous, mucinous, endometrioid, and clear cell subtypes. The expression of α-SMA and PCNA were calculated in cells and stroma of ovarian tumors. Collagen was detected using Sirius Red staining and presented as area fraction.

Results:

The overexpressions of α-SMA in tumor cells were only detected in serous and clear cell ovarian carcinoma. The histoscore of α-SMA was higher in malignant than in benign or borderline ovarian epithelial neoplasms (105.3±129.9 vs. 17.3±17.1, P=0.011; mean±SD). Oppositely, stromal α-SMA and collagen area fractions were higher in benign than in malignant tumors (27.2±6.6 vs 20.5±8.4, P=0.028; 31.0±5.6 vs. 23.7±6.4, P=0.04). The percentages of epithelial and stromal PCNA expressions were not significantly different between benign and malignant tumors.

Conclusion:

Tumor cells of serous and clear cell ovarian carcinoma exhibit mesenchymal characteristic as shown by α-SMA positive expression. This expression might indicate that these subtypes were more aggressive. This research showed that collagen and α-SMA area fractions in stroma were higher in benign than in malignant neoplasms.

Sphingosine kinase 1 is required for TGF-β mediated fibroblastto- myofibroblast differentiation in ovarian cancer

Sphingosine kinase 1 (SPHK1), the enzyme that produces sphingosine 1 phosphate (S1P), is known to be highly expressed in many cancers. However, the role of SPHK1 in cells of the tumor stroma remains unclear. Here, we show that SPHK1 is highly expressed in the tumor stroma of high-grade serous ovarian cancer (HGSC), and is required for the differentiation and tumor promoting function of cancer-associated fibroblasts (CAFs). Knockout or pharmacological inhibition of SPHK1 in ovarian fibroblasts attenuated TGF-β-induced expression of CAF markers, and reduced their ability to promote ovarian cancer cell migration and invasion in a coculture system. Mechanistically, we determined that SPHK1 mediates TGF-β signaling via the transactivation of S1P receptors (S1PR2 and S1PR3), leading to p38 MAPK phosphorylation. The importance of stromal SPHK1 in tumorigenesis was confirmed in vivo, by demonstrating a significant reduction of tumor growth and metastasis in SPHK1 knockout mice. Collectively, these findings demonstrate the potential of SPHK1 inhibition as a novel stroma-targeted therapy in HGSC.

Regulation of chemo-sensitivity in ovarian cancer via a stroma dependent glutathione pathway

The primary chemotherapeutic agents for epithelial ovarian cancer are platinum-based drugs, which are commonly used in combination with a taxane regimen. These treatments are generally effective at achieving remission, but the remission is often followed by a relapse and acquired resistance to chemotherapy. In order to overcome these barriers of drug resistance, it is important to understand the underlying mechanisms regulating the development of drug-resistant tumors. Tumors evolve through interactions with the surrounding microenvironment, which are comprised of a complex mixture of cells including fibroblasts and immune cells. In ovarian cancer, fibroblasts can make up a significant component of the primary tumor. While fibroblasts are known to influence the behavior of cancer cells directly through secretion of growth factors, and extracellular matrix (ECM) proteins, the interactions between fibroblasts and immune cells are less understood. In a recently published study from Cell, Wang and colleagues present intriguing work characterizing the role of fibroblast and T cells in modulating platinum resistance in ovarian cancer. Here, we briefly summarize and comment on their findings in relation to the tumor microenvironment and chemoresistance.

Microenvironmental InterFereNce of metabolism regulates chemosensitivity

The tumor microenvironment is recognized as a critical regulator of cancer progression, and multiple roles are also emerging for the microenvironment in modulating response to therapeutic intervention. A recent study by Wang and colleagues identified IFN-γ as a central effector of CD8 T cell-mediated regulation of glutathione and cysteine metabolism in fibroblasts, which consequently abrogates stromal-induced resistance through modulation of cisplatin intracellular content in ovarian cancer cells.

Fibroblast recruitment as a tool for ovarian cancer detection and targeted therapy

Metastatic ovarian cancer, the most lethal of gynecologic malignancies, is typically managed by debulking surgery, followed by chemotherapy. However, despite significant efforts, survival rate remains low. We have previously demonstrated, in mouse models, a specific systemic homing of labeled fibroblasts to solid ovarian tumors. Here, we demonstrate the feasibility of utilizing this specific homing of genetically modified fibroblasts for detection and targeted therapy of orthotopic metastatic ovarian carcinoma model in immune-deficient mice. Using an in vivo metastatic mouse model for ovarian cancer, we demonstrated that fibroblasts expressing fluorescent reporters injected intra-peritoneally, were specifically recruited to peritoneal tumor nodules (resulting in 93-100% co-localization). We further used fibroblasts over expressing the soluble receptor variant of VEGFR1 (s-Flt1). Mice bearing tumors were injected weekly with either control or s-Flt1 expressing fibroblasts. Injection of s-Flt1 expressing fibroblasts resulted in a significant reduction in the ascites volume, reduced vascularization of adherent metastases, and improved overall survival. Using fluorescently labeled fibroblasts for tumor detection with readily available intra-operative fluorescence imaging tools may be useful for tumor staging and directing biopsies or surgical efforts during exploratory or debulking surgery. Fibroblasts may serve as a beacon pointing to the otherwise invisible metastases in the peritoneal cavity of ovarian cancer patients. Utilizing the recruited fibroblasts also for targeted delivery of anti angiogenic or antitumor molecules may aid in controlling tumor progression. Thus, these results suggest a novel approach for targeting ovarian tumor metastases for both tumor detection and therapy.

Targeting Stromal-Cancer Cell Crosstalk Networks in Ovarian Cancer Treatment

Ovarian cancer is a histologically, clinically, and molecularly diverse disease with a five-year survival rate of less than 30%. It has been estimated that approximately 21,980 new cases of epithelial ovarian cancer will be diagnosed and 14,270 deaths will occur in the United States in 2015, making it the most lethal gynecologic malignancy. Ovarian tumor tissue is composed of cancer cells and a collection of different stromal cells. There is increasing evidence that demonstrates that stromal involvement is important in ovarian cancer pathogenesis. Therefore, stroma-specific signaling pathways, stroma-derived factors, and genetic changes in the tumor stroma present unique opportunities for improving the diagnosis and treatment of ovarian cancer. Cancer-associated fibroblasts (CAFs) are one of the major components of the tumor stroma that have demonstrated supportive roles in tumor progression. In this review, we highlight various types of signaling crosstalk between ovarian cancer cells and stromal cells, particularly with CAFs. In addition to evaluating the importance of signaling crosstalk in ovarian cancer progression, we discuss approaches that can be used to target tumor-promoting signaling crosstalk and how these approaches can be translated into potential ovarian cancer treatment.

The prognostic significance of tumour-stroma ratio in endometrial carcinoma

Background

High tumour stromal content has been found to predict adverse clinical outcome in a range of epithelial tumours. The aim of this study was to assess the prognostic significance of tumour-stroma ratio (TSR) in endometrial adenocarcinomas and investigate its relationship with other clinicopathological parameters.

Methods

Clinicopathological and 5-year follow-up data were obtained for a retrospective series of endometrial adenocarcinoma patients (n = 400). TSR was measured using a morphometric approach (point counting) on digitised histologic hysterectomy specimens. Inter-observer agreement was determined using Cohen’s Kappa statistic. TSR cut-offs were optimised using log-rank functions and prognostic significance of TSR on overall survival (OS) and disease-free survival (DFS) were determined using Cox Proportional Hazards regression analysis and Kaplan-Meier curves generated. Associations of TSR with other clinicopathological parameters were determined using non-parametric tests followed by Holm-Bonferroni correction for multiple comparisons.

Results

TSR as a continuous variable associated with worse OS (P = 0.034) in univariable Cox-regression analysis. Using the optimal cut-off TSR value of 1.3, TSR-high (i.e. low stroma) was associated with worse OS (HR = 2.51; 95 % CI = 1.22–5.12; P = 0.021) and DFS (HR = 2.19; 95 % CI = 1.15–4.17; P = 0.017) in univariable analysis. However, TSR did not have independent prognostic significance in multivariable analysis, when adjusted for known prognostic variables. A highly significant association was found between TSR and tumour grade (P < 0.001) and lymphovascular space invasion (P < 0.001), both of which had independent prognostic significance in this study population.

Conclusions

Low tumour stromal content associates with both poor outcome and with other adverse prognostic indicators in endometrial cancer, although it is not independently prognostic. These findings contrast with studies on many - although not all - cancers and suggest that the biology of tumour-stroma interactions may differ amongst cancer types.

The role of reproductive hormones in epithelial ovarian carcinogenesis

Epithelial ovarian cancer comprises ∼85% of all ovarian cancer cases. Despite acceptance regarding the influence of reproductive hormones on ovarian cancer risk and considerable advances in the understanding of epithelial ovarian carcinogenesis on a molecular level, complete understanding of the biologic processes underlying malignant transformation of ovarian surface epithelium is lacking. Various hypotheses have been proposed over the past several decades to explain the etiology of the disease. The role of reproductive hormones in epithelial ovarian carcinogenesis remains a key topic of research. Primary questions in the field of ovarian cancer biology center on its developmental cell of origin, the positive and negative effects of each class of hormones on ovarian cancer initiation and progression, and the role of the immune system in the ovarian cancer microenvironment. The development of the female reproductive tract is dictated by the hormonal milieu during embryogenesis. Intensive research efforts have revealed that ovarian cancer is a heterogenous disease that may develop from multiple extra-ovarian tissues, including both Müllerian (fallopian tubes, endometrium) and non-Müllerian structures (gastrointestinal tissue), contributing to its heterogeneity and distinct histologic subtypes. The mechanism underlying ovarian localization, however, remains unclear. Here, we discuss the role of reproductive hormones in influencing the immune system and tipping the balance against or in favor of developing ovarian cancer. We comment on animal models that are critical for experimentally validating existing hypotheses in key areas of endocrine research and useful for preclinical drug development. Finally, we address emerging therapeutic trends directed against ovarian cancer.

Pericytes Promote Malignant Ovarian Cancer Progression in Mice and Predict Poor Prognosis in Serous Ovarian Cancer Patients

PURPOSE

The aim of this study was to investigate the role of pericytes in regulating malignant ovarian cancer progression.

EXPERIMENTAL DESIGN

The pericyte mRNA signature was used to interrogate ovarian cancer patient datasets to determine its prognostic value for recurrence and mortality. Xenograft models of ovarian cancer were used to determine if co-injection with pericytes affected tumor growth rate and metastasis, whereas co-culture models were utilized to investigate the direct effect of pericytes on ovarian cancer cells. Pericyte markers were used to stain patient tissue samples to ascertain their use in prognosis.

RESULTS

Interrogation of two serous ovarian cancer patient datasets [the Australian Ovarian Cancer Study, n= 215; and the NCI TCGA (The Cancer Genome Atlas), n= 408] showed that a high pericyte score is highly predictive for poor patient prognosis. Co-injection of ovarian cancer (OVCAR-5 & -8) cells with pericytes in a xenograft model resulted in accelerated ovarian tumor growth, and aggressive metastases, without altering tumor vasculature. Pericyte co-culture in vitro promoted ovarian cancer cell proliferation and invasion. High αSMA protein levels in patient tissue microarrays were correlated with more aggressive disease and earlier recurrence.

CONCLUSIONS

High pericyte score provides the best means to date of identifying patients with ovarian cancer at high risk of rapid relapse and mortality (mean progression-free survival time < 9 months). The stroma contains rare yet extremely potent locally resident mesenchymal stem cells-a subset of "cancer-associated fibroblasts" that promote aggressive tumor growth and metastatic dissemination, underlying the prognostic capacity of a high pericyte score to strongly predict earlier relapse and mortality.

Cellular and molecular processes in ovarian cancer metastasis. A Review in the Theme: Cell and Molecular Processes in Cancer Metastasis

Ovarian cancer is the most lethal gynecological malignancy. It is usually diagnosed at a late stage, with a 5-yr survival rate of <30%. The majority of ovarian cancer cases are diagnosed after tumors have widely spread within the peritoneal cavity, limiting the effectiveness of debulking surgery and chemotherapy. Owing to a substantially lower survival rate at late stages of disease than at earlier stages, the major cause of ovarian cancer deaths is believed to be therapy-resistant metastasis. Although metastasis plays a crucial role in promoting ovarian tumor progression and decreasing patient survival rates, the underlying mechanisms of ovarian cancer spread have yet to be thoroughly explored. For many years, researchers have believed that ovarian cancer metastasizes via a passive mechanism by which ovarian cancer cells are shed from the primary tumor and carried by the physiological movement of peritoneal fluid to the peritoneum and omentum. However, the recent discovery of hematogenous metastasis of ovarian cancer to the omentum via circulating tumor cells instigated rethinking of the mode of ovarian cancer metastasis and the importance of the "seed-and-soil" hypothesis for ovarian cancer metastasis. In this review we discuss the possible mechanisms by which ovarian cancer cells metastasize from the primary tumor to the omentum, the cross-talk signaling events between ovarian cancer cells and various stromal cells that play crucial roles in ovarian cancer metastasis, and the possible clinical implications of these findings in the management of this deadly, highly metastatic disease.

Granulosa Cell-Specific Brca1 Loss Alone or Combined with Trp53 Haploinsufficiency and Transgenic FSH Expression Fails to Induce Ovarian Tumors

BRCA1 mutations are associated with ovarian cancer. Previous studies reported that murine granulosa cell (GC) Brca1 loss caused ovarian-uterine tumors resembling serous cystadenomas, but the pathogenesis of these tumors may have been confounded by ectopic Brca1 expression and altered estrous cycling. We have used Tg.AMH.Cre conferring proven ovarian and GC-specific Cre activity to selectively target Brca1 disruption, denoted Brca1(GC-/-). Furthermore, ovary-specific Brca1(GC-/-) was combined with global Trp53 haploinsufficiency (Trp53(+/-)) and transgenic follicle-stimulating hormone (Tg.FSH) overexpression as a multi-hit strategy to investigate additional genetic and hormonal ovarian tumorigenesis mechanisms. However, 12-month-old Brca1(GC-/-) mice had no detectable ovarian or uterine tumors. Brca1(GC-/-) mice had significantly increased ovary weights, follicles exhibiting more pyknotic granulosa cells, and fewer corpora lutea with regular estrous cycling compared to controls. Isolated Brca1(GC-/-) mutation lengthened the estrous cycle and proestrus stage; however, ovarian cystadenomas were not observed, even when Brca1(GC-/-) was combined with Trp53(+/-) and overexpressed Tg.FSH. Our Brca1(GC-/-) models reveal that specific intra-follicular Brca1 loss alone, or combined with cancer-promoting genetic (Trp53 loss) and endocrine (high serum FSH) changes, was not sufficient to cause ovarian tumors. Our findings show that the ovary is remarkably resistant to oncogenesis, and support the emerging view of an extragonadal, multi-hit origin for ovarian tumorigenesis.

Primary ovarian carcinomas and abdominal metastasis contain 4,6-disulfated chondroitin sulfate rich regions, which provide adhesive properties to tumour cells

High mortality in ovarian cancer patients is primarily caused through rapid metastasis of the tumour, but the underlying mechanisms are poorly understood. Glycosaminoglycans, are abundantly present in tumours and chondroitin sulfate-E (CSE), a highly 4,6-sulfated glycosaminoglycan, has been indicated to play a role in carcinogenesis. In this study we investigated the presence of CSE in ovarian cancer metastasis and studied its role in tumour cell adhesiveness and migration. CSE was studied immunohistochemically in primary ovarian carcinomas and abdominal metastases using the single chain antibody GD3G7. The role of CSE was studied in 2D (scratch assays) and 3D (collagen matrices, spheroids) systems using SKOV3 cells applying 1: overexpression of CSE by stable transfection with DNA encoding GalNAc4S-6 sulfotransferase, 2: enzymatic removal of CS, and 3: addition of CSE. In ovarian cancer tissue, CSE expression was predominantly seen in the stromal compartment of both primary ovarian carcinomas and metastases, with a comparable degree of intensity and extent. Overexpression of CSE disaccharide units by tumour cells increased their adhesive properties which was especially seen in tumour spheroid formation. Increased expression of CSE reduced cell migration. Addition of free CSE had similar effects. The data presented here indicate that CSE is associated with metastatic lesions and that it provides tumours with adhesive properties. CSE rich motifs are put forward as a potential target for ovarian cancer therapy.