Serous Ovarian Cancer Tissues Research Articles

Identification of MAD2L1 and BUB1B as Potential Biomarkers Associated with Progression and Prognosis of Ovarian Cancer.

Ovarian cancer develops insidiously and is frequently diagnosed at advanced stages. Screening for ovarian cancer is an effective strategy for reducing mortality. This study aimed to investigate the molecular mechanisms underlying the development of ovarian cancer and identify novel tumor biomarkers for the diagnosis and prognosis of ovarian cancer. Three databases containing gene expression profiles specific to serous ovarian cancer (GSE18520, GSE12470, and GSE26712) were acquired. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes were analyzed for the differentially expressed gene (DEGs). The protein-protein interaction (PPI) network was constructed using the STRING database. The pivotal genes in the PPI network were screened using the Cytoscape software. Survival curve analysis was performed using a Kaplan-Meier Plotter. The cancer genome atlas and Gene Expression Omnibus databases were used to find the relationship between Hub gene and serous ovarian cancer. PCR and immunohistochemistry were used to detect the expression of Hub gene in serous ovarian cancer tissues and cells. Downstream pathways of the candidate tumor marker genes were predicted using Gene Set Enrichment Analysis. In this study, 252 DEGs were screened for pathway enrichment. 20 Hub genes were identified. Survival analysis suggested that Aurka, Bub1b, Cenpf, Cks1b, Kif20a, Mad2l1, Racgap1, and Ube2c were associated with the survival of patients with serous ovarian cancer. MAD2L1 and BUB1B levels were significantly different in serous ovarian cancer at different stages. Finally, Mad2l1 was found to play a role in the cell cycle, oocyte meiosis, and ubiquitin-mediated proteolysis. Meanwhile, Bub1b may play a role in the cell cycle, ubiquitin-mediated proteolysis, and spliceosome processes. Mad2l1 and Bub1b could be used as markers to predict ovarian carcinogenesis and prognosis, providing candidate targets for the diagnosis and treatment of serous ovarian cancer.

Unraveling the molecular mechanisms of lymph node metastasis in ovarian cancer: focus on MEOX1

BackgroundLymph node metastasis (LNM) is a major factor contributing to the high mortality rate of ovarian cancer, making the treatment of this disease challenging. However, the molecular mechanism underlying LNM in ovarian cancer is still not well understood, posing a significant obstacle to overcome.ResultsThrough data mining from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, we have identified MEOX1 as a specific gene associated with LNM in ovarian cancer. The expression of MEOX1 was found to be relatively high in serous ovarian adenocarcinoma, and its higher expression were associated with increased tumor grade and poorer clinical prognosis for ovarian cancer patients. Bioinformatics analysis revealed that MEOX1 exhibited the highest mRNA levels among all cancer types in ovarian cancer tissues and cell lines. Furthermore, gene set enrichment analysis (GSEA) and pathway analysis demonstrated that MEOX1 was involved in various LNM-related biological activities, such as lymphangiogenesis, lymphatic vessel formation during metastasis, epithelial-mesenchymal transition (EMT), G2/M checkpoint, degradation of extracellular matrix, and collagen formation. Additionally, the expression of MEOX1 was positively correlated with the expression of numerous prolymphangiogenic factors in ovarian cancer. To validate our findings, we conducted experiments using clinical tissue specimens and cell lines, which confirmed that MEOX1 was highly expressed in high-grade serous ovarian cancer (HGSOC) tissues and various ovarian cancer cell lines (A2780, SKOV3, HO8910, and OVCAR5) compared to normal ovarian tissues and normal ovarian epithelial cell line IOSE-80, respectively. Notably, we observed a higher protein level of MEOX1 in tumor tissues of LNM-positive HGSOC compared to LNM-negative HGSOC. Moreover, our fundamental experiments demonstrated that suppression of MEOX1 led to inhibitory effects on ovarian cancer cell proliferation and EMT, while overexpression of MEOX1 enhanced the proliferation and EMT capacities of ovarian cancer cells.ConclusionsThe results of our study indicate that MEOX1 plays a role in the lymph node metastasis of ovarian cancer by regulating multiple biological activities, including the proliferation and EMT of ovarian cancer, lymphangiogenesis, and ECM remodeling. Our findings suggest that MEOX1 could serve as a potential biomarker for the diagnosis and treatment of ovarian cancer with LNM.

Proteogenomic analysis of enriched HGSOC tumor epithelium identifies prognostic signatures and therapeutic vulnerabilities

We performed a deep proteogenomic analysis of bulk tumor and laser microdissection enriched tumor cell populations from high-grade serous ovarian cancer (HGSOC) tissue specimens spanning a broad spectrum of purity. We identified patients with longer progression-free survival had increased immune-related signatures and validated proteins correlating with tumor-infiltrating lymphocytes in 65 tumors from an independent cohort of HGSOC patients, as well as with overall survival in an additional 126 HGSOC patient cohort. We identified that homologous recombination deficient (HRD) tumors are enriched in pathways associated with metabolism and oxidative phosphorylation that we validated in independent patient cohorts. We further identified that polycomb complex protein BMI-1 is elevated in HR proficient (HRP) tumors, that elevated BMI-1 correlates with poor overall survival in HRP but not HRD HGSOC patients, and that HRP HGSOC cells are uniquely sensitive to BMI-1 inhibition.

Comparative analysis between high-grade serous ovarian cancer and healthy ovarian tissues using single-cell RNA sequencing.

High-grade serous ovarian cancer (HGSOC) is the most common histological subtype of ovarian cancer, and is associated with high mortality rates. In this study, we analyzed specific cell subpopulations and compared different gene functions between healthy ovarian and ovarian cancer cells using single-cell RNA sequencing (ScRNA-seq). We delved deeper into the differences between healthy ovarian and ovarian cancer cells at different levels, and performed specific analysis on endothelial cells. We obtained scRNA-seq data of 6867 and 17056 cells from healthy ovarian samples and ovarian cancer samples, respectively. The transcriptional profiles of the groups differed at various stages of ovarian cell development. A detailed comparison of the cell cycle, and cell communication of different groups, revealed significant differences between healthy ovarian and ovarian cancer cells. We also found that apoptosis-related genes, URI1, PAK2, PARP1, CLU and TIMP3, were highly expressed, while immune-related genes, UBB, RPL11, CAV1, NUPR1 and Hsp90ab1, were lowly expressed in ovarian cancer cells. The results of the ScRNA-seq were verified using qPCR. Our findings revealed differences in function, gene expression and cell interaction patterns between ovarian cancer and healthy ovarian cell populations. These findings provide key insights on further research into the treatment of ovarian cancer.

Label-Free Quantification Mass Spectrometry Identifies Protein Markers of Chemotherapy Response in High-Grade Serous Ovarian Cancer

Eighty percent of ovarian cancer patients initially respond to chemotherapy, but the majority eventually experience a relapse and die from the disease with acquired chemoresistance. In addition, 20% of patients do not respond to treatment at all, as their disease is intrinsically chemotherapy resistant. Data-independent acquisition nano-flow liquid chromatography-mass spectrometry (DIA LC-MS) identified the three protein markers: gelsolin (GSN), calmodulin (CALM1), and thioredoxin (TXN), to be elevated in high-grade serous ovarian cancer (HGSOC) tissues from patients that responded to chemotherapy compared to those who did not; the differential expression of the three protein markers was confirmed by immunohistochemistry. Analysis of the online GENT2 database showed that mRNA levels of GSN, CALM1, and TXN were decreased in HGSOC compared to fallopian tube epithelium. Elevated levels of GSN and TXN mRNA expression correlated with increased overall and progression-free survival, respectively, in a Kaplan-Meier analysis of a large online repository of HGSOC patient data. Importantly, differential expression of the three protein markers was further confirmed when comparing parental OVCAR-5 cells to carboplatin-resistant OVCAR-5 cells using DIA LC-MS analysis. Our findings suggest that GSN, CALM1, and TXN may be useful biomarkers for predicting chemotherapy response and understanding the mechanisms of chemotherapy resistance. Proteomic data are available via ProteomeXchange with identifier PXD033785.

Abstract 2266: Tumor associated neutrophils (TAN) may produce neutrophil extracellular traps (NETs) which can suppress the infiltration of activated T cells in tumor tissue

Abstract Objective: High density of tumor-infiltrating lymphocytes (TIL) in the tumor is associated with favorable prognosis of cancer patients. It has been reported that many neutrophils also infiltrate in various tumor tissues as tumor-associated neutrophils (TAN) which produce considerable amounts of neutrophil extracellular traps (NETs). However, the crosstalk between TAN and TIL and its impact on tumor behavior have not been fully examined. Methods: Neutrophils and mononuclear cells (PBMC) were collected from the blood of healthy donor. Neutrophils were stimulated with PMA or LPS for 15 min, washed extensively, and incubated for another 4 hours to produce NETs. PBMC were cultured on anti-CD3 mAb-coated plate with recombinant-IL-2 for 7-14days. The migration of activated T cells through 3μm pore to CXCL-11 was examined in vitro. The localization and densities of TAN and TIL were immunohistochemically evaluated in 38 human serous ovarian cancer tissue. NETs were quantified with the density of CD66b(+) and Citrullinated Histon H3(+) cells. Results: Chemotactic migration of T cells to CXCL-11 was inhibited by 99%±1.6% (p<0.001) in the presence of PMA-activated neutrophils in lower chamber. The inhibition was similarly detected when NET components were removed by ultracentrifugation. Timelapse analysis also showed the NETs-depleted supernatant inhibited random migration, which was totally canceled by the pretreatment with catalase. When neutrophils were activated by LPS, T cell migration was also inhibited by 49%±19.9% (p<0.01), but not by NETs-depleted supernatant. In western blotting, CXCL11 was totally degraded by LPS-stimulated neutrophils, which was greatly reduced by the depletion of NET component and restored by DNase I as well as phenylmethylsulfonyl fluoride (PMSF) or Neutrophil elastase inhibitor (NEI). The reduced migration induced by LPS-stimulated neutrophils was also restored with these reagents. In ovarian cancer tissues, density of TIL was greater in tumors with diameter ≥10cm than that of tumors <10cm (p=0.04). However, the densities of TIL and NETs were irrelevant with age, tumor stage and neutrophil-to-lymphocyte ratio (NLR) in peripheral blood. Multicolor immunohistochemistry showed that TAN and TIL tended to be reciprocally distributed in tumor stroma in most of the ovarian cancer tissues. Cit-H3 was positively detected in 2.1%~75% of CD66b(+) TANs, and the proportion of NET in TAN greatly varied among tumors. In all cases, the densities of CD4(+) and CD8(+) T cells inversely correlated with that of NETs (r = -0.5182, p = 0.0012; r = -0.5684, p = 0.0003, respectively). Conclusion: Activated neutrophils negatively regulate T cell migration partially through NET formation. TAN may suppress T cell traffic into tumor tissue, which may attenuate cell-mediated immunity in tumor microenvironment and promote tumor progression. Citation Format: Kohei Tamura, Hideyo Miyato, Misaki Matsumiya, Rei Takahashi, Yuki Kaneko, Yurie Futoh, Kazuya Takahashi, Yuki Kimura, Akira Saito, Hideyuki Ohzawa, Yasushi Saga, Yuji Takei, Hiroyuki Fujiwara, Joji Kitayama. Tumor associated neutrophils (TAN) may produce neutrophil extracellular traps (NETs) which can suppress the infiltration of activated T cells in tumor tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2266.

Oncogene-mediated nuclear accumulation of lactate promotes epigenetic alterations to induce cancer cell proliferation.

Homeobox gene families are associated with embryonic development and organogenesis. Pieces of evidence suggest that these Homeobox genes are also crucial in facilitating oncogenesis when mutated or overexpressed. Paired homeodomain transcription factor-2 (PITX2), one of the members of this family, is involved in oncogenic regulation apart from its different development regulatory functions. PITX2 has been earlier shown to induce ovarian cancer cell proliferation through the activation of different signaling cascades. Increased cancer cell proliferation requires a constant supply of nutrients for both adenosine triphosphate and biomass synthesis, which is facilitated by altered cancer cell metabolism that includes enhanced glucose uptake and increased glycolytic rate. This present study highlights the involvement of PITX2 in enhancing the cellular glycolysis pathway in ovarian cancer cells through protein kinase B-phosphorylation (phospho-AKT). PITX2 expression correlates positively with that of the glycolytic rate-determining enzyme, lactate dehydrogenase-A (LDHA), in both high-grade serous ovarian cancer tissues and common ovarian cancer cell lines. Interestingly, transient localization of enzymatically active LDHA in the nucleus was observed in PITX2-overexpressed ovarian cancer cells. This nuclear LDHA produces higher concentrations of the glycolytic end product, lactate, which accumulates in the nuclear compartment resulting in decreased histone deacetylase (HDAC1/2) expression and increased histone acetylation at H3/H4. However, the mechanistic details of lactate-HDAC interaction are still elusive in the earlier reports. Our in silico studies elaborated on the interaction dynamics of lactate in the HDAC catalytic core through ligand-binding studies and molecular dynamics simulation approaches. Blocking lactate production by silencing LDHA reduced cancer cell proliferation. Thus, PITX2-induced epigenetic changes can lead to high cellular proliferation and increase the size of tumors in syngeneic mice as well. Taken together, this is the first report of its kind to show that the developmental regulatory homeobox gene PITX2 could enhance oncogenesis through enhanced glycolysis of tumor cells followed by epigenetic modifications.

Establishment of Epithelial Cell Culture from Ovarian Cancer Tissues: A Method Comparison Study.

This study aimed to determine the most effective method in establishing primary cell culture from epithelial serous ovarian cancer tissues with the highest yield of cells and percentage of epithelial cells. Primary and metastasis tissues from three serous ovarian cancer patients were processed using 18 different combinations of methods based on different factors: the source of tissue (primary site or metastasis site), the cell suspension method (explant method, enzymatic methods, or the addition of Percoll), and the alternatives of three different media. We compared the total count of cells, the percentage of epithelial cells, and the estimated number of epithelial cells per observation field. The calculation of cells from primary tissues were compared to metastasis tissues, and the difference was statistically analyzed using Mann Whitney-U test on SPSS software. The groups that were processed using dispase and trypsin resulted higher number of cells and higher percentage of epithelial cells when compared to the explant method. Among all media, we found that DMEM:F12 and McCoy's 5A media as equally useful in isolating and culturing epithelial cells. Statistically, the metastasis tissue derived more epithelial cells when compared to the primary tissue (102.32±82.65 vs 22.6±23.81, p=0.001). The use of metastasis tissue processed with trypsin or dispase and cultured in DMEM:F12 or McCoy's 5A media was found to be the most efficient way to produce the highest amount of cells with high percentage of epithelial cells.

LRRC superfamily expression in stromal cells predicts the clinical prognosis and platinum resistance of ovarian cancer

BackgroundLeucine-rich repeat sequence domains are known to mediate protein‒protein interactions. Recently, some studies showed that members of the leucine rich repeat containing (LRRC) protein superfamily may become new targets for the diagnosis and treatment of tumours. However, it is not known whether any of the LRRC superfamily genes is expressed in the stroma of ovarian cancer (OC) and is associated with prognosis.MethodsThe clinical data and transcriptional profiles of OC patients from the public databases TCGA (n = 427), GTEx (n = 88) and GEO (GSE40266 and GSE40595) were analysed by R software. A nomogram model was also generated through R. An online public database was used for auxiliary analysis of prognosis, immune infiltration and protein‒protein interaction (PPI) networks. Immunohistochemistry and qPCR were performed to determine the protein and mRNA levels of genes in high-grade serous ovarian cancer (HGSC) tissues of participants and the MRC-5 cell line induced by TGF-β.ResultsLRRC15 and LRRC32 were identified as differentially expressed genes from the LRRC superfamily by GEO transcriptome analysis. PPI network analysis suggested that they were most enriched in TGF-β signalling. The TCGA-GTEx analysis results showed that only LRRC15 was highly expressed in both cancer-associated fibroblasts (CAFs) and the tumour stroma of OC and was related to clinical prognosis. Based on this, we developed a nomogram model to predict the incidence of adverse outcomes in OC. Moreover, LRRC15 was positively correlated with CAF infiltration and negatively correlated with CD8 + T-cell infiltration. As a single indicator, LRRC15 had the highest accuracy (AUC = 0.920) in predicting the outcome of primary platinum resistance.ConclusionsThe LRRC superfamily is related to the TGF-β pathway in the microenvironment of OC. LRRC15, as a stromal biomarker, can predict the clinical prognosis of HGSC and promote the immunosuppressive microenvironment. LRRC15 may be a potential therapeutic target for reversing primary resistance in OC.

Integrating single-cell RNA sequencing and prognostic model revealed the carcinogenicity and clinical significance of FAM83D in ovarian cancer.

Ovarian cancer (OC) is a fatal gynecological tumor with high mortality and poor prognosis. Yet, its molecular mechanism is still not fully explored, and early prognostic markers are still missing. In this study, we assessed carcinogenicity and clinical significance of family with sequence similarity 83 member D (FAM83D) in ovarian cancer by integrating single-cell RNA sequencing (scRNA-seq) and a prognostic model. A 10x scRNA-seq analysis was performed on cells from normal ovary and high-grade serous ovarian cancer (HGSOC) tissue. The prognostic model was constructed by Lasso-Cox regression analysis. The biological function of FAM83D on cell growth, invasion, migration, and drug sensitivity was examined in vitro in OC cell lines. Luciferase reporter assay was performed for binding analysis between FAM83D and microRNA-138-5p (miR-138-5p). Our integrative analysis identified a subset of malignant epithelial cells (C1) with epithelial-mesenchymal transition (EMT) and potential hyperproliferation gene signature. A FAM83D+ malignant epithelial subcluster (FAM83D+ MEC) was associated with cell cycle regulation, apoptosis, DNA repair, and EMT activation. FAM83D resulted as a viable prognostic marker in a prognostic model that efficiently predict the overall survival of OC patients. FAM83D downregulation in SKOV3 and A2780 cells increased cisplatin sensitivity, reducing OC cell proliferation, migration, and invasion. MiR-138-5p was identified to regulate FAM83D's carcinogenic effect in OC cells. Our findings highlight the importance of miR-138 -5p/FAM83D/EMT signaling and may provide new insights into therapeutic strategies for OC.

Ovarian cancer immunogenicity is governed by a narrow subset of progenitor tissue-resident memory T-cells

Abstract Despite repeated associations between T-cell infiltration and patient outcome, human ovarian cancer remains poorly responsive to immunotherapy. We report that hallmarks of tumor recognition in ovarian cancer-infiltrating T-cells are primarily restricted to tissue-resident memory (TRM) cells. In mouse models we found that TRM T-cells were better than the re-circulating counterpart at controlling tumor growth. Single-cell RNA/TCR/ATAC sequencing of 83,454 CD3+CD8+CD103+CD69+ TRM cells and 24,175 CD3+CD8+CD103− re-circulating TILs showed that progenitor (TCF1low) tissue-resident memory T-cells (TRMstem cells) arise from transitional recirculating T-cells, which depends on antigen affinity/persistence, resulting in oligoclonal, trogocytic, effector lymphocytes. This effector population develops into proliferative lymphocytes that eventually become exhausted TRMs. Immunohistochemistry of 122 high-grade serous ovarian cancer tissues showed that only TRMstem cells, but not re-circulating TCF1+ T-cells, predict ovarian cancer outcome. Therefore, ovarian cancer is indeed an immunogenic disease that depends on ~13% of CD8+ tumor-infiltrating T-cells (~3% of CD8+ clonotypes), which are primed against high-affinity antigens and maintain waves of effector TRM cells. Support for Shared Resources was provided by Cancer Center Support Grant (CCSG) CA076292 to H. Lee Moffitt Cancer Center and by CCSG CA010815 to The Wistar Institute. This study was supported by grants from NIH (R01CA157664, R01CA124515, R01CA178687, R01CA211913 and U01CA232758 to JRCG; R01CA184185 and RO1CA262121 to PCR.)

Mechanomimetic 3D Scaffolds as a Humanized In Vitro Model for Ovarian Cancer.

The mechanical homeostasis of tissues can be altered in response to trauma or disease, such as cancer, resulting in altered mechanotransduction pathways that have been shown to impact tumor development, progression, and the efficacy of therapeutic approaches. Specifically, ovarian cancer progression is parallel to an increase in tissue stiffness and fibrosis. With in vivo models proving difficult to study, tying tissue mechanics to altered cellular and molecular properties necessitate advanced, tunable, in vitro 3D models able to mimic normal and tumor mechanic features. First, we characterized normal human ovary and high-grade serous (HGSC) ovarian cancer tissue stiffness to precisely mimic their mechanical features on collagen I-based sponge scaffolds, soft (NS) and stiff (MS), respectively. We utilized three ovarian cancer cell lines (OVCAR-3, Caov-3, and SKOV3) to evaluate changes in viability, morphology, proliferation, and sensitivity to doxorubicin and liposomal doxorubicin treatment in response to a mechanically different microenvironment. High substrate stiffness promoted the proliferation of Caov-3 and SKOV3 cells without changing their morphology, and upregulated mechanosensors YAP/TAZ only in SKOV3 cells. After 7 days in culture, both OVCAR3 and SKOV3 decreased the MS scaffold storage modulus (stiffness), suggesting a link between cell proliferation and the softening of the matrix. Finally, high matrix stiffness resulted in higher OVCAR-3 and SKOV3 cell cytotoxicity in response to doxorubicin. This study demonstrates the promise of biomimetic porous scaffolds for effective inclusion of mechanical parameters in 3D cancer modeling. Furthermore, this work establishes the use of porous scaffolds for studying ovarian cancer cells response to mechanical changes in the microenvironment and as a meaningful platform from which to investigate chemoresistance and drug response.

Reduced RBPMS Levels Promote Cell Proliferation and Decrease Cisplatin Sensitivity in Ovarian Cancer Cells.

Worldwide, the number of cancer-related deaths continues to increase due to the ability of cancer cells to become chemotherapy-resistant and metastasize. For women with ovarian cancer, a staggering 70% will become resistant to the front-line therapy, cisplatin. Although many mechanisms of cisplatin resistance have been proposed, the key mechanisms of such resistance remain elusive. The RNA binding protein with multiple splicing (RBPMS) binds to nascent RNA transcripts and regulates splicing, transport, localization, and stability. Evidence indicates that RBPMS also binds to protein members of the AP-1 transcription factor complex repressing its activity. Until now, little has been known about the biological function of RBPMS in ovarian cancer. Accordingly, we interrogated available Internet databases and found that ovarian cancer patients with high RBPMS levels live longer compared to patients with low RBPMS levels. Similarly, immunohistochemical (IHC) analysis in a tissue array of ovarian cancer patient samples showed that serous ovarian cancer tissues showed weaker RBPMS staining when compared with normal ovarian tissues. We generated clustered regularly interspaced short palindromic repeats (CRISPR)-mediated RBPMS knockout vectors that were stably transfected in the high-grade serous ovarian cancer cell line, OVCAR3. The knockout of RBPMS in these cells was confirmed via bioinformatics analysis, real-time PCR, and Western blot analysis. We found that the RBPMS knockout clones grew faster and had increased invasiveness than the control CRISPR clones. RBPMS knockout also reduced the sensitivity of the OVCAR3 cells to cisplatin treatment. Moreover, β-galactosidase (β-Gal) measurements showed that RBPMS knockdown induced senescence in ovarian cancer cells. We performed RNAseq in the RBPMS knockout clones and identified several downstream-RBPMS transcripts, including non-coding RNAs (ncRNAs) and protein-coding genes associated with alteration of the tumor microenvironment as well as those with oncogenic or tumor suppressor capabilities. Moreover, proteomic studies confirmed that RBPMS regulates the expression of proteins involved in cell detoxification, RNA processing, and cytoskeleton network and cell integrity. Interrogation of the Kaplan–Meier (KM) plotter database identified multiple downstream-RBPMS effectors that could be used as prognostic and response-to-therapy biomarkers in ovarian cancer. These studies suggest that RBPMS acts as a tumor suppressor gene and that lower levels of RBPMS promote the cisplatin resistance of ovarian cancer cells.

Label-free diagnosis of ovarian cancer using spoof surface plasmon polariton resonant biosensor

Artificial periodic grooves on a metal line can mimic optical surface plasmon polaritons (SPPs) with high cut-off response at microwave frequencies, which is known as spoof SPPs and has recently gained great interest in biosensing due to the strong enhancement of the localized electric field. In this paper, a sensitive spoof SPP biosensor with split ring resonators (SRRs) for ovarian cancer diagnosis is reported for the first time. The SRRs are distributed in series on a metal line to replace the conventional periodic grooves, which maintains the same cut-off frequency and generates a sharp resonance simultaneously. This resonance enhances the localized field by a factor of 250 so that the proposed device is highly sensitive for detecting permittivity difference. The sensitivity in terms of frequency shifting was first investigated by electromagnetic simulation, and then demonstrated by distinguishing sucrose solutions with various concentrations. With the benefit of high sensitivity, the proposed biosensor successfully detects the serous ovarian cancer (SOC) and ovarian clear cell carcinoma (OCCC) tissues. The resonant frequency of the biosensor is 53.990 GHz intrinsically, which shifts to 53.814–53.968, 53.698–53.872, and 53.719–53.845 GHz with the normal, SOC, and OCCC tissues, respectively. The average point of all ovarian tissues is at 53.812 GHz, i.e., well below the normal tissues, which is a reasonable reference for cancer detection. Moreover, the average transmittance of all cancerous tissues is lower than the SOC tissues, which may be used to classify the SOC and OCCC tissues. The proposed planar SPP biosensor reveals a fast, sensitive, and label-free detection approach for ovarian cancers.

Abstract 103: Spatially resolved transcriptomics identified distinct tumor-stroma crosstalk networks in long term ovarian cancer survivors

Abstract The tumor microenvironment (TME), composed primarily of fibroblasts, endothelial cells, lymphocytic infiltrates and extracellular matrix proteins, can directly affect cancer cell growth, migration, differentiation as well as immune cell landscapes, thereby presenting a unique aspect of diagnosing and treating cancer. Cancer-associated fibroblasts (CAF) and immune cells are the main orchestrators of the ovarian cancer TME. We hypothesized that spatial transcriptomics (ST), which can provide a rich spatial context to gene expression, will identify crosstalk signaling networks among various cell types in the ovarian TME. Advanced stage high-grade serous ovarian cancer (HGSC) tissue frozen sections from two treatment naïve long-term survivors (LTS, overall survival ≥ 10 years) and two short-term survivors (STS, overall survival ≤ 2 years) were placed onto a ST expression slide pre-spotted with 1000 unique barcoded RNA-capturing probes. The ST slides were then stained with H&E and imaged. Tissue permeabilization and cDNA synthesis were then performed directly on the tissue section. The derived barcoded cDNA libraries from each sample were sequenced using Illumina NextSeq500 flow cells. After RNA-Seq analysis, supervised analysis was then performed by selecting different regions (based on tissue histology) in the tumor, tumor/stroma mixture, stroma close or far away from tumor areas to identify differentially expressed genes between STS and LTS. Stromal cells from different spatial locations had unique differentially expressed genes based on their proximity (11 genes in LTS; 11 genes in STS) or remoteness (18 genes in LTS; 10 genes in STS) to cancer cell compartments. Among the major modulated gene networks, higher levels of antigen-presenting molecules were found in the stroma in close proximity to the tumor cell nest than in stroma located far away in LTS tumor samples but not in the STS samples, suggesting an increased number of activated antigen-presenting cells in LTS tumors. In addition, higher levels of adhesion molecules and angiogenetic factors were found in the stroma in close proximity to the tumor cell nest than in stroma located far away in STS tumor samples but not in LTS samples, suggesting that adhesion molecules and angiogenetic factors produced by stromal cells may facilitate the invasiveness of the tumor cells, which subsequently leads to short term survival in patients with the disease. Our findings demonstrate for the first time that spatially resolved transcriptomics allows the identification of prognostic biomarkers associated with overall survival in HGSC patients. Further studies using deconvoluted ST data to further delineate the specific stromal cell subtypes in close proximity to tumors, and imaging mass cytometry (IMC) or multiplexed immunohistochemistry to validate the protein expression of the potential biomarkers are ongoing. Citation Format: Sammy Ferri-Borgogno, Jianting Sheng, Ying Zhu, Kwong K. Wong, Stephen T. Wong, Samuel C. Mok. Spatially resolved transcriptomics identified distinct tumor-stroma crosstalk networks in long term ovarian cancer survivors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 103.

Abstract 2503: Crispr/cas-9-mediated genome editing reveals that RBPMS acts as a tumor suppressor in ovarian cancer

Abstract RNA-Binding Protein with Multiple Splicing (RBPMS) is a member of a family of proteins that bind to the nascent RNA transcripts and regulate their processing, which includes pre-mRNA splicing and transport/localization/stability of the RNA molecule. Evidence indicates that RBPMS also binds to members of the AP-1 (c-Jun and c-Fos) transcription factor repressing his activity. Until now, little is known about the biological function of RBPMS in ovarian cancer. To understand the role of RBPMS in ovarian cancer we generated CRISPR (clustered regularly interspaced short palindromic repeats)-mediated RBPMS knock-out vectors that were stably transfected in the ovarian cancer cells OVCAR3. The Guide-it Genotype confirmation Kit was used to determine the type of mutations (monoallelic, biallelic, or unchanged) present in the developed clones. Additionally, resulting CRISPR-cleavage products were analyzed to establish the cleavage efficiency of the Cas9/sgRNA complex by densitometry analysis. We found that CRISPR clone cells grow faster and increase their invasiveness ability compared with control CRISPR cells. Furthermore, immunohistochemical (IHC) analysis in a tissue array showed that RBPMS staining was significantly lower in high-grade serous ovarian cancer (HGSOC) tissues as compared to normal ovarian tissues. RBPMS was also decreased in platinum-resistant ovarian cancer cells as compared to platinum-sensitive cancer cells. Senescence-associated β-galactosidase (β-Gal) levels were higher in CRISPR-clones as compared with empty vector and ovarian cancer cells, which suggest RBPMS knockdown induces senescence. These studies along with the data of proteomics and RNAseq suggest that RBPMS acts as a tumor suppressor gene and lower levels of RBPMS are associated with the cisplatin resistance of ovarian cancer cells. Citation Format: Rohit K. Sharma, Ginette S. Santiago-Sánchez, Robert J. Rabelo-Fernández, Blanca I. Quiñones-Díaz, Fatima Valiyeva, Pablo E. Vivas-Mejia. Crispr/cas-9-mediated genome editing reveals that RBPMS acts as a tumor suppressor in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2503.

Development of Aptamer-Based Molecular Tools for Rapid Intraoperative Diagnosis and In Vivo Imaging of Serous Ovarian Cancer.

Diagnosis and treatment of ovarian cancer are based on intraoperative pathology and debulking surgery. The development of a novel molecular tool is significant for rapid intraoperative pathologic diagnosis, which instructs the decision-making on excision surgery and effective chemotherapy. In this work, we represent a DNA aptamer named mApoc46, which is generated from cell-SELEX by targeting patient-derived primary serous ovarian cancer (pSOC) cells. An average dissociation constant (Kd) was determined to be 0.15 ± 0.05 μM by flow cytometry. The mApoc46 aptamer displays a robust specificity to pSOC cells. Labeled with FAM, mApoc46 can selectively stain living pSOC cells in 30 min without staining commercial OC cell lines and cell lines associated with other cancers. Interestingly, FAM-mApoc46 displayed superb selectivity toward high-grade serous ovarian cancer (HG-SOC) tissues in frozen sections against low-grade SOC, ovarian borderline tumor, other nonepithelial ovarian tumors, and healthy ovarian tissue. These results lead to a potential application in the identification of OCs' histological subtypes during operation. In the patient-derived tumor xenograft NCG mice model, Cy5-labeled mApoc46 was found to accumulate at the tumor area and served as an in vivo imaging probe. The mApoc46 probe shows a robust and stable performance to visualize SOC tumors in the body. Therefore, aptamer mApoc46 holds great potential in rapid intraoperative detection, pathological diagnosis, fluorescence image-guided cancer surgery, and targeted drug delivery and therapy.

Prognostic Value of TNFR2 and STAT3 among High-Grade Serous Ovarian Cancer Survivors According to Platinum Sensitivity.

This study’s goal was to determine the protein expression level of tumour necrosis factor receptor 2 (TNFR2) and signal transducer and activator of transcription 3 (STAT3) in high-grade serous ovarian cancer (HGSC) tissues in relation to the platinum-based chemotherapy response and the prognosis outcome. A total of 25 HGSC patients underwent primary surgical debulking followed by first-line adjuvant platinum-based chemotherapy. Tissue microarray (TMA) slides were constructed utilising archived formalin fixed paraffin embedded (FFPE). The protein expression of TNFR2 and STAT3 were analysed using immunohistochemistry (IHC) staining and subsequently were correlated to the clinicopathological characteristics, platinum sensitivity as well as the duration of progression-free survival. About 14 out of 25 patients (56.0%) were platinum-sensitive. The progression free survival was significantly longer in the platinum-sensitive (PS) group when compared to those with the platinum-resistant group (PR), p = 0.0001. Among patients with TNFR2 strong expression on ovarian tissue, there was a significantly longer progression-free survival interval of 540 days in the PS group compared to PR, p = 0.0001. Patients with STAT3 expression also showed significantly better progression-free survival of 660 days in the PS group when compared to the PR group, p = 0.0001. In conclusion, patients with strong TNFR2 and STAT3 expression in the ovarian tissue had significantly longer progression-free survival interval in the PS group. Nevertheless, further research with a larger number of tissues may be required to demonstrate further significant differences.

ABCA1 is associated with the development of acquired chemotherapy resistance and predicts poor ovarian cancer outcome.

Aim: This study investigated the ATP binding cassette (ABC) transporter (ABCA1, ABCB1, ABCB3, ABCC2 and ABCG2) expression in high grade serous ovarian cancer (HGSOC) tissues, cell lines and primary cells to determine their potential relationship with acquired chemotherapy resistance and patient outcome.Methods: ABC transporter mRNA and protein expression (ABCA1, ABCB1, ABCB3, ABCC2 and ABCG2) was assessed in publicly available datasets and in a tissue microarray (TMA) cohort of HGSOC at diagnosis, respectively. ABC transporter mRNA expression was also assessed in chemosensitive ovarian cancer cell lines (OVCAR-5 and CaOV3) versus matching cell lines with acquired carboplatin resistance and in primary HGSOC cells from patients with chemosensitive disease at diagnosis (n = 10) as well as patients with acquired chemotherapy resistance at relapse (n = 6). The effects of the ABCA1 inhibitor apabetalone in carboplatin-sensitive and -resistant cell lines were also investigated.Results: High ABCA1 mRNA and protein expression was found to be significantly associated with poor patient outcome. ABCA1 mRNA and protein levels were significantly increased in ovarian cancer cell lines (OVCAR-5 CBPR and CaOV3 CBPR) with acquired carboplatin resistance. ABCA1 mRNA was significantly increased in primary HGSOC cells obtained from patients with acquired chemotherapy resistance. Apabetalone treatment reduced ABCA1 protein expression and increased the sensitivity of both parental and carboplatin-resistant ovarian cancer cells to carboplatin.Conclusion: These results suggest that inhibiting ABCA1 transporter may be useful in overcoming acquired chemotherapy resistance and improving outcome for patients with HGSOC.

HDAC6 Degradation Inhibits the Growth of High-Grade Serous Ovarian Cancer Cells.

Simple SummaryThe objective of this study was, firstly, to investigate the relationship between Histone deacetylase 6 (HDAC6) expression and survival in patients with ovarian cancer and, secondly, to test the effects of histone deacetylase 6 (HDAC6) inhibition on ovarian cancer cells in vitro. A meta-analysis of the correlation between HDAC6 gene expression and survival was performed on 3573 ovarian tumors from 19 datasets showed that high HDAC6 gene expression was associated with a decreased risk of death. Knockdown of HDAC6 gene expression with small interfering RNA (siRNA) and protein expression with a HDAC6 targeting protein degrader decreased ovarian cell proliferation, migration, and viability. Conversely, the selective inhibition of HDAC6 catalytic activity did not produce a robust inhibition of HDAC6 protein function. In summary, we demonstrated, for the first time, that HDAC6 over-expression in ovarian cancers is a favorable prognostic marker. We provide evidence to suggest that inhibition of HDAC6 catalytic activity has limited efficacy as a monotherapy in ovarian cancers.Histone deacetylase 6 (HDAC6) is a unique histone deacetylating enzyme that resides in the cell cytoplasm and is linked to the modulation of several key cancer related responses, including cell proliferation and migration. The promising anti-cancer response of the first-generation HDAC6 catalytic inhibitors continues to be assessed in clinical trials, although its role in high grade serous ovarian cancer is unclear. This study investigated HDAC6 tumor expression by immunohistochemistry in high-grade serous ovarian cancer (HGSOC) tissue samples and a meta-analysis of HDAC6 gene expression in ovarian cancer from publicly available data. The pharmacological activity of HDAC6 inhibition was assessed in a patient-derived model of HGSOC. HDAC6 was found to be highly expressed in HGSOC tissue samples and in the patient-derived HGSOC cell lines where higher HDAC6 protein and gene expression was associated with a decreased risk of death (hazard ratio (HR) 0.38, (95% confidence interval (CI), 0.16–0.88; p = 0.02); HR = 0.88 (95% CI, 0.78–0.99; p = 0.04)). Similarly, the multivariate analysis of HDAC6 protein expression, adjusting for stage, grade, and cytoreduction/cytoreductive surgery was associated with a decreased risk of death (HR = 0.19 (95% CI, 0.06–0.55); p = 0.002). Knock-down of HDAC6 gene expression with siRNA and protein expression with a HDAC6 targeting protein degrader decreased HGSOC cell proliferation, migration, and viability. Conversely, the selective inhibition of HDAC6 with the catalytic domain inhibitor, Ricolinostat (ACY-1215), inhibited HDAC6 deacetylation of α-tubulin, resulting in a sustained accumulation of acetylated α-tubulin up to 24 h in HGSOC cells, did not produce a robust inhibition of HDAC6 protein function. Inhibition of HGSOC cell proliferation by ACY-1215 was only achieved with significantly higher and non-selective doses of ACY-1215. In summary, we demonstrated, for the first time, that HDAC6 over-expression in HGSOC and all ovarian cancers is a favorable prognostic marker. We provide evidence to suggest that inhibition of HDAC6 catalytic activity with first generation HDAC6 inhibitors has limited efficacy as a monotherapy in HGSOC.