Human Epithelial Ovarian Cancer Research Articles

Towards a ‘hot’ tumor phenotype: DKN-01 sensitizes the tumor micro-environment via pro-immune cell cytokine release in vitro and ex vivo

<h3>Objectives:</h3> The Wnt/-catenin pathway has been associated with a ‘cold' tumor microenvironment (TME) in ovarian cancer that allows for unregulated tumor progression. We characterized the impact of inhibiting DKK1 - a Wnt pathway target gene - on immune-related molecular responses in ovarian cancer. <h3>Methods:</h3> Data was collected from human cell lines, ascites collected from patients with HGSOC, and tissue from patient tumor samples treated with a DKK-1 inhibitor (DKN-01.) Ascites from 10 high grade serous ovarian cancer (HGSOC) patients were isolated, cultured <i>in vitro,</i> and treated with control or 0.5uL/mL DKN-01 for 48 hours. Cell lysates were collected for multiplex cytokine/chemokine array. Human ES2 epithelial ovarian cancer (EOC) cells were cultured <i>in vitro</i> and treated with control or DKN-01; RNA-sequencing was performed to characterize differential gene expression changes in response to treatment. We also performed H&E staining of human tumor tissue from six patients with recurrent gynecologic malignancies (EEC, MMMT, EOC), pre- and post-DKN-01 monotherapy. <h3>Results:</h3> DKK1 blockade via DKN-01 was associated with an enhanced pro-inflammatory response as exhibited by enhanced inflammatory cytokine/chemokine gene expression and secretion; these findings were associated with improved local immune cell presence. In human ascites, there was a >20% increase in IL-8, CCL5 and CCL4 cytokines in response to DKN-01; these cytokines are associated with enhanced leukocyte, T cell, NK cell, and monocyte recruitment. Additionally, there was a >20% increase in CXCL9 and EGF cytokines (both associated with T cell activation), and GM-CSF (associated with pro-inflammatory/anti-tumor M1 macrophage polarization) in response to DKN-01. RNA-seq analysis of human ovarian tissue from patients with DKN-01 treatment showed a statistically significant increases in gene expression of pro-inflammatory chemokines CXCL8 (p<0.001) and IL-18BP (p<0.05) compared to matched controls. <h3>Conclusions:</h3> DKK1 blockade facilitates a pro-inflammatory TME via increased local immunostimulatory cytokine production and release, providing a mechanism of action for improved clinical outcomes for gynecologic cancer patients by creating a ‘hot' TME. Based on these findings, further studies are needed to investigate how DKK-1 inhibition could prime the TME to sensitize ovarian cancer to immune checkpoint blockade.

Targeting the CD47-SIRPα pathway promotes macrophage-mediated trogocytosis of ovarian cancer cells

Targeting the CD47-SIRPα pathway promotes macrophage-mediated trogocytosis of ovarian cancer cells

Nuclear HKII-P-p53 (Ser15) Interaction is a Prognostic Biomarker for Chemoresponsiveness and Glycolytic Regulation in Epithelial Ovarian Cancer.

Simple SummaryHexokinase II (HKII) is a key glycolysis enzyme associated with tumorigenesis, but its molecular mechanism and pathophysiological role in chemoresistant ovarian cancer remain elusive. In this study, we delineate the novel mechanism showing that activated phosphorylated-p53 (P-p53 Ser15) is required for the regulation of HKII intracellular trafficking and metabolic regulation in chemosensitive ovarian cancer, but not in chemoresistant ovarian cancer harboring p53 mutation. We have observed that increased nuclear HKII-P-p53 (Ser15) interaction is likely associated with chemosensitivity and better survival outcomes in epithelial ovarian cell lines, human primary epithelial ovarian cancer cells, and tumor sections. Nuclear HKII-P-p53 (Ser15) interaction may function as a promising prognostic biomarker, enabling prediction of patients with poor prognosis for deciding better clinical strategies.In epithelial ovarian cancer (EOC), carboplatin/cisplatin-induced chemoresistance is a major hurdle to successful treatment. Aerobic glycolysis is a common characteristic of cancer. However, the role of glycolytic metabolism in chemoresistance and its impact on clinical outcomes in EOC are not clear. Here, we show a functional interaction between the key glycolytic enzyme hexokinase II (HKII) and activated P-p53 (Ser15) in the regulation of bioenergetics and chemosensitivity. Using translational approaches with proximity ligation assessment in cancer cells and human EOC tumor sections, we showed that nuclear HKII-P-p53 (Ser15) interaction is increased after chemotherapy, and functions as a determinant of chemoresponsiveness as a prognostic biomarker. We also demonstrated that p53 is required for the intracellular nuclear HKII trafficking in the control of glycolysis in EOC, associated with chemosensitivity. Mechanistically, cisplatin-induced P-p53 (Ser15) recruits HKII and apoptosis-inducing factor (AIF) in chemosensitive EOC cells, enabling their translocation from the mitochondria to the nucleus, eliciting AIF-induced apoptosis. Conversely, in p53-defective chemoresistant EOC cells, HKII and AIF are strongly bound in the mitochondria and, therefore, apoptosis is suppressed. Collectively, our findings implicate nuclear HKII-P-p53(Ser15) interaction in chemosensitivity and could provide an effective clinical strategy as a promising biomarker during platinum-based therapy.

TCP1 regulates PI3K/AKT/mTOR signaling pathway to promote proliferation of ovarian cancer cells

ObjectiveTCP1 is one of the eight subunits of the TCP1 ring complex (TRiC) or the multi-protein mammalian cytosolic chaperone complex. TRiC participates in protein folding and regulates the expression of multiple signaling proteins and cytoskeletal components in cells. Although the clinical importance of its subunits has been clarified in various carcinomas, the function of TCP1 in ovarian cancer (OC) remains unclear. We aimed to identify the association between the expression of TCP1 and the development of epithelial OC (EOC) and patient prognosis, and explore the underlying mechanisms of TCP1 on the tumor progression of OC cells.MethodsTCP1 protein expression was tested in various ovarian tissues by immunohistochemistry, and the correlation between TCP1 expression and clinical physiologic or pathologic parameters of patients with EOC was analyzed. The relationship between TCP1 expression and the prognosis of patients with OC was investigated and analyzed using the Kaplan–Meier (KM) plotter online database. The expression level of TCP1 was then tested in different OC cell lines by Western blotting. Further, a model using OC cell line A2780 was constructed to study the functions of TCP1 in growth, migration, and invasion of human EOC cells. Finally, the possible regulating signaling pathways were discussed.ResultsTCP1 protein expression in OC or borderline tissues was significantly higher than that in benign ovarian tumors and normal ovarian tissue. The upregulated expression of TCP1 in OC was positively associated with the differentiation grade and FIGO stage of tumors and predicted poor clinical outcomes. Compared with IOSE-80 cells, TCP1 protein was overexpressed in A2780 cells. TCP1 knockdown using shRNA lentivirus inhibited the viability of A2780 cells. Western blotting showed that the phosphatidylinositol-3 kinase (PI3K) signaling pathway was activated in the tumor invasion in EOC driven by TCP1.ConclusionUpregulated TCP1 is correlated with the poor prognosis of patients with OC. The mechanism of cancer progression promoted by TCP1 upregulation may be linked to the activation of the PI3K signaling pathway, and TCP1 may serve as a novel target for the treatment of OC.

The effect of exosomes derived from human ovarian epithelial cancer cells on the secretion of AMH and Inhibin in granulosa cells

The effect of exosomes derived from human ovarian epithelial cancer cells on the secretion of AMH and Inhibin in granulosa cells

Correlation between HPV infection and ovarian epithelial cancer diagnosed by Dynamic Contrast-enhanced magnetic resonance imaging information technology under exponential distribution mathematical model

This research aims to analyze the correlation between human papillomavirus (HPV) infection and ovarian epithelial cancer based on exponential distribution mathematical model, so as to provide an experimental basis for the early diagnosis of ovarian epithelial cancer by magnetic resonance imaging (MRI) in the future. In this study, 124 patients with ovarian epithelial cancer tissues pathologically confirmed in our hospital from March 31, 2017 to February 20, 2019 were selected as the experimental group, and 64 patients with normal ovarian tissues were selected as the control group, and the positive rate of HPV infection was detected by the computer cell test (CCT) system. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was constructed and adopted to analyze the scanning images. The correlation between HPV infection and pathological type, clinical stage, tissue differentiation degree, and CA125 in serum was studied by exponential distribution mathematical model. The results showed that the positive rate of HPV infection in the ovarian tissues of the experimental group was significantly higher than that of the control group (P < 0.05). Highly differentiated patients accounted for 25.97%, moderately differentiated patients accounted for 43.81%, and lowly differentiated patients accounted for 30.22%. Patients with clinical stage I-II accounted for 24.72%, patients with stage III accounted for 49.11%, and patients with stage IV accounted for 26.17%. HPV infection was significantly correlated with clinical stage III and moderate tissue differentiation by MRI of patients (P < 0.05), and extremely significantly correlated with clinical stage IV and low tissue differentiation by MRI (P < 0.001). The above findings show that the information technology of dynamic contrast-enhanced magnetic resonance imaging can clearly display the lesion metastasis of ovarian epithelial cancer patients with high soft tissue resolution.

Inhibition of sphingosine kinase 2 down-regulates ERK/c-Myc pathway and reduces cell proliferation in human epithelial ovarian cancer.

BackgroundEpithelial ovarian cancer (EOC) is the leading cause of death from female cancers. In our previous study, sphingosine kinase 2 (SphK2) inhibitor was shown to display anti-EOC activities. The purpose of this study was to evaluate further the expression characteristics and clinical significance of SphK2 in EOC and to explore the roles and underlying mechanisms of SphK2 in EOC cell survival.MethodsThe expression of SphK2 was examined by immunohistochemistry (IHC) and Western blot, and its clinical implications and prognostic significance were analyzed. We performed a cellular proliferation assay, and a mouse xenograft model was established to confirm the roles of SphK2 in vitro and in vivo. Cell cycle analysis, apoptosis assay, and Western blot were performed to examine cell cycle progression and apoptosis rate. Gene set enrichment analysis (GSEA), and Western blot were used to investigate the downstream signaling pathways related to SphK2 function.ResultsThe expression level of SphK2 was shown to be associated with stage, histological grade, lymph node metastasis, and ascites status. More importantly, a high SphK2 expression level was a prognostic indicator of overall survival (OS) and relapse-free survival (RFS). Moreover, knockdown of SphK2 arrested cell cycle progression and inhibited EOC cell proliferation both in vitro and in vivo. Furthermore, ERK/c-Myc, the key pathway in EOC progression, was important for SphK2-mediated mitogenic action in EOC cells.ConclusionsOur findings provided the first evidence that SphK2 played a crucial role in EOC proliferation by regulating the ERK/c-Myc pathway. This indicated that SphK2 might serve as a prognostic marker and potential therapeutic target in EOC.

Atrazine Promoted Epithelial Ovarian Cancer Cells Proliferation and Metastasis by Inducing Low Dose Reactive Oxygen Species (ROS).

Background: Atrazine (ATZ) is a triazine herbicide that is widely used in agriculture and has been detected in surface and underground water. Recently, laboratory and epidemiological research have found that the bioaccumulation of ATZ in the environment leads to biotoxicity in the human immune and endocrine systems and results in tumor development.Objective: To investigate the effects of ATZ exposure on epithelial ovarian cancer (EOC) cells and elucidate the potential mechanisms governing these effects.Materials and Methods: The human EOC cell lines Skov3 and A2780 were used in this study to explore the effects and mechanisms of ATZ exposure on EOC. The mouse embryonic osteoblastic precursor MC3T3-E1 cells served as the control cells to determine the effects of ATZ on cancer cell lines. After exposure to ATZ, the MTT assay, flow cytometry, the colony formation assay, immunohistochemical staining, the cell scratch assay, and the Transwell assay were used to evaluate the proliferative activity, invasion, and migration capabilities of EOC cell lines. Moreover, flow cytometry was also applied to detect the level of reactive oxygen species (ROS) in these two EOC cell lines, as well as the MC3T3-E1 cells. To further illustrate the underlying mechanisms governing the effect of ATZ on EOC, real-time PCR and Western blotting were employed to assess the transcription and the expression level of Stat3 signaling pathway-related genes in Skov3 and MC3T3-E1 cells.Results: The results showed that following ATZ treatment, the cell proliferation, migration, and invasion potencies of Skov3 and A2780 cells were increased compared to those of the control group. Meanwhile, the ROS levels of EOC and MC3T3-E1 cells were notably elevated after ATZ treatment. In Skov3 cells, the expression levels of p53 and p21 were downregulated, while those of Cyclin E, vascular endothelial growth factor (VEGF), matrix metallopeptidase 2 (MMP2), MMP9, signal transducers and activators of transcription 3 (Stat3), and p-Stat3 were upregulated by ATZ treatment. In MC3T3-E1 cells, however, ATZ treatment did not affect the level of p53/p21 mRNA compared to the control groups. Moreover, there was no significant change in the expression levels of Stat3 and p-Stat3 in MC3T3-E1 cells exposed to ATZ. This phenomenon was observed while the proliferation rate was enhanced in MC3T3-E1 cells by ATZ.Conclusions: The results of this study suggest that ATZ effectively promotes the proliferation and metastasis of EOC cells through the Stat3 signaling pathway by inducing low levels of ROS. Additionally, although ATZ might also induce proliferative potential in normal cells, the mechanisms governing its effects in these cells might be different from those in EOC cells.

Metformin Reduces NGF-Induced Tumour Promoter Effects in Epithelial Ovarian Cancer Cells.

Epithelial ovarian cancer (EOC) is a lethal gynaecological neoplasm characterized by rapid growth and angiogenesis. Nerve growth factor (NGF) and its high affinity receptor tropomyosin receptor kinase A (TRKA) contribute to EOC progression by increasing the expression of c-MYC, survivin and vascular endothelial growth factor (VEGF) along with a decrease in microRNAs (miR) 23b and 145. We previously reported that metformin prevents NGF-induced proliferation and angiogenic potential of EOC cells. In this study, we sought to obtain a better understanding of the mechanism(s) by which metformin blocks these NGF-induced effects in EOC cells. Human ovarian surface epithelial (HOSE) and EOC (A2780/SKOV3) cells were stimulated with NGF and/or metformin to assess the expression of c-MYC, β-catenin, survivin and VEGF and the abundance of the tumor suppressor miRs 23b and 145. Metformin decreased the NGF-induced transcriptional activity of MYC and β-catenin/T-cell factor/lymphoid enhancer-binding factor (TCF-Lef), as well as the expression of c-MYC, survivin and VEGF in EOC cells, while it increased miR-23b and miR-145 levels. The preliminary analysis of ovarian biopsies from women users or non-users of metformin was consistent with these in vitro results. Our observations shed light on the mechanisms by which metformin may suppress tumour growth in EOC and suggest that metformin should be considered as a possible complementary therapy in EOC treatment.

Intracellular optical doppler phenotypes of chemosensitivity in human epithelial ovarian cancer

Development of an assay to predict response to chemotherapy has remained an elusive goal in cancer research. We report a phenotypic chemosensitivity assay for epithelial ovarian cancer based on Doppler spectroscopy of infrared light scattered from intracellular motions in living three-dimensional tumor biopsy tissue measured in vitro. The study analyzed biospecimens from 20 human patients with epithelial ovarian cancer. Matched primary and metastatic tumor tissues were collected for 3 patients, and an additional 3 patients provided only metastatic tissues. Doppler fluctuation spectra were obtained using full-field optical coherence tomography through off-axis digital holography. Frequencies in the range from 10 mHz to 10 Hz are sensitive to changes in intracellular dynamics caused by platinum-based chemotherapy. Metastatic tumor tissues were found to display a biodynamic phenotype that was similar to primary tissue from patients who had poor clinical outcomes. The biodynamic phenotypic profile correctly classified 90% [88–91% c.i.] of the patients when the metastatic samples were characterized as having a chemoresistant phenotype. This work suggests that Doppler profiling of tissue response to chemotherapy has the potential to predict patient clinical outcomes based on primary, but not metastatic, tumor tissue.

Expression of STAT1 is positively correlated with PD-L1 in human ovarian cancer

ABSTRACT Signal transducer and activator of transcription 1 (STAT1) is related to the immune microenvironment of tumorigenesis. The programmed cell death 1 (PD-1) and its ligand (PD-L1) have been reported to be important in immunotherapy by mediating tumor immune evasion. Blocking the PD-1/PD-L1 pathway can restore the endogenous anti-tumor immune response. This study aimed to examine the expression of STAT1, PD-1, and PD-L1 and the correlation between selected markers in human epithelial ovarian cancer (EOC). The results showed that malignant tumors contained more STAT1, PD-1, and PD-L1 positive cells. The expression of STAT1 and PD-L1 was associated with age, whereas PD-1 and PD-L1 associated with histopathological type, in patients with ovarian tumors. Moreover, the expression of STAT1 was found to be associated with disease stages and the grade of serous carcinoma. STAT1 expression was higher in OC cells than normal ovarian surface epithelial cells and was positively correlated with PD-L1 expression. The knockdown of STAT1 decreased PD-L1 expression, whereas overexpression of STAT1 increased PD-L1 expression. Furthermore, the expression of STAT1, PD-1, and PD-L1 was lower in paclitaxel-resistant cells than sensitive cells. Finally, STAT1 affected the overall survival and progression-free survival of patients with EOC. These findings suggest that STAT1, PD-1, and PD-L1 are the tissue markers of EOC and imply the possibility that the high level of STAT1, PD-1, and PD-L1 may favor the checkpoint immunotherapy in patients with EOC, but may have a limit in paclitaxel-resistant patients because of the low expression of STAT1, PD-1, and PD-L1 in paclitaxel-resistant cells.

Platinum-based chemotherapy and bevacizumab-induced mitochondrial damage in human epithelial ovarian cancers via different pathways

Objective: Ovarian cancer remains the principal cause of gynecologic cancer death worldwide. The standard chemotherapeutic approaches to this cancer are platinum-based chemotherapy (carboplatin and paclitaxel) and bevacizumab (BEV). However, the effects of both platinum-based chemotherapy and BEV on mitochondrial damage in isolated mitochondria from human epithelial ovarian cancers have not yet been investigated. Therefore, the present study aimed to test the hypothesis that platinum-based chemotherapy and BEV equally damage the mitochondria from human epithelial ovarian cancers via increased mitochondrial dysfunction, mitophagy, and mitochondrial apoptosis.

In Vitro Assessment of Magnetic Liposomal Paclitaxel Nanoparticles as a Potential Carrier for the Treatment of Ovarian Cancer.

Purpose: This study aimed to evaluate the role of magnetic liposome nanoparticles (ML NPs) as a carrier for paclitaxel (PTX) for the treatment of ovarian cancer in vitro.Methods: Magnetic NPs (MNPs) were synthesized by chemical co-precipitation method. The resulting NPs were characterized in terms of size, size distribution, zeta potential, drug encapsulation efficiency (EE), drug release pattern, and cytotoxicity effects.Results: The size and zeta potential of PTX-PEG-L and PTX-PEG-ML NPs were determined to be 296, 198 nm; -20, and -19 mV, respectively. Also, their drug encapsulation efficiencies were determined to be 97% and 96%, respectively. It was found that PTX-PEG-ML NPs, compared to PTX-PEG-L NPs, caused a reduction (11%) in the rate of drug release. The cytotoxicity of the drug-loaded NPs was assessed using 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay against human ovarian epithelial cancer (A2780CP) cells, and the results demonstrated that PTX-PEG-ML NPs caused higher cytotoxicity (by 14%) compared to PTX-PEG-L NPs (IC50: 1.88 ± 0.09 and 2.142 ± 0.1 µM, respectively).Conclusion: Overall, the results of this study suggest that PTX-PEG-ML NPs could be considered as a therapeutic candidate for the treatment of ovarian cancer.

Abstract A56: Novel L-sugar linked glycosylated antitumor ether lipids for killing platinum-resistant human epithelial ovarian cancer cells

Abstract Glycosylated antitumor ether lipids (GAELs) are a promising class of investigational anticancer agents with potent antitumor activity against a range of cancers, including platinum-resistant high-grade serous ovarian cancer (HGSOC). We previously demonstrated that epithelial ovarian cancer (EOC) cell lines (HGSOC and endometrioid) and primary cells derived from patient ascites (HGSOC and clear cell) were sensitive to the cell-killing effects of D-glucosamine-derived GAELs via an apoptosis-independent mechanism. However, D-linked carbohydrates are metabolized by endogenous glucosidases in vivo, rendering the GAEL inactive. Thus, the aim of the current study was to synthesize a novel class of GAELs with L-linked carbohydrates and to evaluate their efficacy in EOC cell lines and patient samples. Out of seven novel compounds tested, L-rhamnose-GAEL was identified as the compound with the greatest efficacy for killing EOC cell lines and patient cells that were grown under adherent or nonadherent (3D) conditions. The drug-sensitive and drug-resistant syngeneic endometrioid EOC cell lines, A2780s and A2780cp, respectively, as well as the NIH:OVCAR-3 and COV362 HGSOC lines, were incubated with L-rhamnose-GAEL for 48 hours and the CC50 determined as 15 μM for A2780s, 22.5 μM for A2780cp, and 5 μM for NIH:OVCAR-3 and COV362 cells. Similar experiments were conducted with primary EOC cells, chemo-naïve EOC126 (clear-cell adenocarcinoma), and platinum-resistant EOC 183I (HGSOC). Cell viability decreased in a dose-dependent manner with CC50 of 12 μM for EOC126 and 22.5 μM for EOC183l. For comparison, when EOC126 and EOC183I were grown as 3D cultures the CC50for cisplatin was 20 μM and 40 μM, respectively. To evaluate the effect of using low-dose treatment of L-rhamnose-GAEL on primary EOC cells (chemo-naive and chemoresistant), cells were exposed to L-rhamnose-GAEL for 96 hours. These studies revealed that prolonged incubation led to low CC50 of 1-5 μM. These results showed that primary EOC cells derived from chemo-naïve and platinum-resistant patients were sensitive to the L-rhamnose-GAEL and offer a novel drug class capable of killing chemotherapy-resistant EOC cells. Citation Format: Mark W. Nachtigal, Frank Schweizer, Gilbert Arthur. Novel L-sugar linked glycosylated antitumor ether lipids for killing platinum-resistant human epithelial ovarian cancer cells [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr A56.

Suppressive activities of mangiferin on human epithelial ovarian cancer

BackgroundEpithelial carcinoma is a subtype of ovarian cancers, with the highest lethality among all ovarian cancer subtypes. Hitherto surgical excision combined with chemotherapy has been the most extensively employed method in clinical treatment. However, the disease relapses very frequently, calling for more effective therapies. Mangiferin, a natural xanthone glucoside, has displayed promising anti-cancer activities by in vitro studies, but its therapeutic value in epithelial ovarian cancer treatment, either by in vivo or in vitro studies, remained to be known. PurposeThis study aimed to determine the suppressive activities of mangiferin on human epithelial ovarian cancer and elucidate the underlying molecular mechanisms. Study design and methodsWe employed the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the crystal violet assay to determine the half maximal inhibitory concentration (IC50) values of mangiferin with paclitaxel as a positive control and the inhibitory effects of mangiferin on the proliferation of two human epithelial ovarian cancer cell lines. Wound healing and Transwell assays were used to determine anti-metastastic activities of mangiferin. ES-2 xenograft nude mouse model was used for the in vivo experiments. Western blotting, enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) assays were carried out for evaluating the expression level of matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9). ResultsIn the present study, we demonstrated by both in vitro and in vivo assays that mangiferin suppressed the progress of epithelial ovarian cancer in a dose-dependent manner. In the animals treated with mangiferin, the tumor volume and weight were reduced significantly. Analyses of involved molecular events demonstrated that mangiferin down-regulated the expression of metastasis-associated proteins MMP2 and MMP9. ConclusionMangiferin strongly inhibited the progression of human epithelial ovarian cancer by down-regulating MMP2 and MMP9.

Apomorphine facilitates loss of respiratory chain activity in human epithelial ovarian cancer and inhibits angiogenesis in vivo

Apomorphine, a therapeutic agent for neurological diseases, is structurally similar to dopamine, and thereby holds potential in cancer therapy. However, there are no reports regarding its anti-cancer effects on human epithelial ovarian cancers (EOCs); therefore, we aimed to elucidate the mechanism underlying its action after drug repositioning. Apomorphine inhibited the proliferation of ES2 and OV90 EOC cells by inducing caspase activation and mitochondrion-associated apoptosis; it also promoted endoplasmic reticulum stress and mitochondrial dysfunction through mitochondrial membrane potential depolarization and mitochondrial calcium overload. Moreover, following apomorphine treatment, we noted the loss of respiratory chain activity by reduction of oxidative phosphorylation and energy-production shift in EOC cells. Further, we verified the anti-angiogenic capacity of apomorphine using fli:eGFP transgenic zebrafish. As a preclinical assessment, we demonstrated the synergistic anti-cancer effects of apomorphine and paclitaxel combination.

Ultrasound-Mediated Long-Circulating Nanopolymer Delivery of Therapeutic siRNA and Antisense MicroRNAs Leads to Enhanced Paclitaxel Sensitivity in Epithelial Ovarian Cancer Chemotherapy.

Epithelial ovarian cancer (EOC) is one of the leading malignant tumors that seriously threaten women's health. The development of new drugs or increasing the sensitivities of current chemotherapy drugs is critically needed. The purpose of this study was to assess the synergistic effects of two silencing RNAs [salt-inducible kinase 2 (SIK2) siRNA and antisense-microRNA21 (anti-miR21)] encapsulated in long-circulating folate-lipid-poly(lactic-co-glycolic acid) (PLGA) hybrid nanopolymers (FaLPHNPs) administered using an ultrasound- and microbubble (US-MB)-mediated approach to sensitize human EOC xenografts to paclitaxel (PTX). In the in vitro assays, this lipid-PLGA hybrid nanopolymer exhibited an extended circulation profile (t1/2: ∼8.5 h); US-MB-mediated complementary delivery of FaLPHNPs resulted in a significant reduction in EOC cell (OVCR3, A2780, and SKOV3) proliferation. In vivo, there was a 2.5-fold increase (p < 0.05) in RNA delivery in EOC xenografts, which resulted in a notable inhibition of tumor growth compared with that in the non-ultrasound-mediated and PTX alone-treated controls. We validated the therapeutic roles of SIK2, the target gene in treating advanced ovarian cancer, and anti-miR21 by evaluating the significant inhibition of tumor growth upon SIK2 silencing and inhibition of endogenous miR21 function. In summary, the results of this study revealed that US-MB-mediated codelivery of SIK2 siRNA, and anti-miR21 encapsulated in a folate-lipid-PLGA hybrid polymer nanoparticle could significantly improve the sensitivity of EOC tumors to PTX and is a highly effective approach for treating EOC in complementary experiments. Further research of this strategy could lead to better treatment results for patients with EOC.

Abstract B33: Genomic analysis of immunosuppressive and proangiogenic genes in recombinant HE4 treated immune cells and implications for T-cell cytotoxicity in ovarian cancer cell co-culture

Abstract Objective: To determine the effect of HE4 on expression of immune-related genes in CD8+ T cells and explore the role of HE4 in immunosuppression and angiogenesis in epithelial ovarian cancer (EOC). Methods: Tissue HE4 levels and T cell counts were determined by immunohistochemistry (IHC). Recombinant HE4 (rHE4)-mediated gene expression in CD8+ T cells was measured by qPCR array. Cytokine levels were determined using a human cytokine array. Cell viability of ovarian cancer cells co-cultured with pooled peripheral blood mononuclear cells (PBMC) in the presence or absence of rHE4 was determined using MTS cell viability reagent. P-values were determined by unpaired 2-tailed student t test. Activation of STAT3 was evaluated by Western blot, and the interaction of STAT3 and HE4 was queried by immunoprecipitation of STAT3. Finally, HE4 and IL8 levels were measured by IHC in a microarray of human EOC and normal adjacent tissue (NAT), and levels were correlated using Spearman Rank test. Results: Tissue HE4 levels correlated with CD8+ T cell counts in EOC. rHE4 treatment of CD8+ T cells upregulated expression of a panel of immunosuppressive and proangiogenic genes, including VEGF, HIF1A, STAT3, IDO1, FOXP3, and IL8. IL8 was most robustly upregulated (99-fold vs control). HE4 also resulted in alterations in cytokine levels in ovarian cancer cells co-cultured with PBMCs. OVCAR8 and SKOV3 ovarian cancer cell lines were treated with rHE4, and levels of phospho-STAT3—a known regulator of IL8—were measured. HE4 was found to activate STAT3 in a time-dependent manner, which occurred in the absence of a physical interaction between HE4 and STAT3. rHE4 treatment of OVCAR8 and SKOV3 cells co-cultured with PBMCs suppressed PBMC-mediated cytotoxicity. Finally, IL8 and HE4 mean levels were elevated in EOC tissue compared to NAT and significantly correlated (R=0.49332; p=0.00142). Conclusions: HE4 upregulates expression of genes involved in promoting a proangiogenic and immunosuppressive microenvironment in EOC, which may play a role in reduced cytotoxic ability of immune cells. Upregulation of IL8 may occur via HE4 regulation of STAT3 signaling. Future directions include testing the effect of HE4 on endothelial cell angiogenesis and determining if STAT3 and VEGF inhibitors modulate HE4 suppression of immune cell cytotoxicity. Citation Format: Nicole James, Jenna Emerson, Ashley Borgstadt, Lindsey Beffa, Anze Urh, Kyukwang Kim, Rakesh Singh, Richard Moore, Paul DiSilvestro, Jennifer Ribeiro. Genomic analysis of immunosuppressive and proangiogenic genes in recombinant HE4 treated immune cells and implications for T-cell cytotoxicity in ovarian cancer cell co-culture [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B33.

Global DNA Hypomethylation in Epithelial Ovarian Cancer: Passive Demethylation and Association with Genomic Instability.

A hallmark of human cancer is global DNA hypomethylation (GDHO), but the mechanisms accounting for this defect and its pathological consequences have not been investigated in human epithelial ovarian cancer (EOC). In EOC, GDHO was associated with advanced disease and reduced overall and disease-free survival. GDHO (+) EOC tumors displayed a proliferative gene expression signature, including FOXM1 and CCNE1 overexpression. Furthermore, DNA hypomethylation in these tumors was enriched within genomic blocks (hypomethylated blocks) that overlapped late-replicating regions, lamina-associated domains, PRC2 binding sites, and the H3K27me3 histone mark. Increased proliferation coupled with hypomethylated blocks at late-replicating regions suggests a passive hypomethylation mechanism. This hypothesis was further supported by our observation that cytosine DNA methyltransferases (DNMTs) and UHRF1 showed significantly reduced expression in GDHO (+) EOC after normalization to canonical proliferation markers, including MKI67. Finally, GDHO (+) EOC tumors had elevated chromosomal instability (CIN), and copy number alterations (CNA) were enriched at the DNA hypomethylated blocks. Together, these findings implicate a passive DNA demethylation mechanism in ovarian cancer that is associated with genomic instability and poor prognosis.

Oncogenic and drug-sensitive RET mutations in human epithelial ovarian cancer

BackgroundEpithelial ovarian cancer (EOC) is a highly lethal malignancy. Improvement in genetic characterization of EOC patients is required to propose new potential targets, since surgical resection coupled to chemotherapy, presents several limits such as cancer recurrence and drug resistance. Targeted therapies have more efficacy and less toxicity than standard treatments. One of the most relevant cancer-specific actionable targets are protein tyrosine kinases (PTKs) whose role in EOC need to be better investigated.MethodsEOC genomic datasets are retrieved and analyzed. The biological and clinical significance of RET genomic aberrations in ovarian cancer context are investigated by a series of in vitro and in vivo experiments.ResultsEpithelial ovarian cancer sequencing projects identify recurrent genomic RET missense mutations in 1.98% of patients, ranking as the top-five hit among the 100 receptor tyrosine kinases-encoding genes. RET mutants R693H and A750T show oncogenic transformation properties in NIH3T3 cells. Introduction of the RET mutants into human EOC cells increases RET signaling, cell viability, anchorage-independent cell growth and tumor xenograft growth in nude mice, demonstrating that they are activating mutations. RET mutants significantly enhance the activation of RET and its downstream MAPK and AKT signaling pathway in ovarian cancer cells. Vandetanib, a clinical approved RET inhibitor, inhibits the cell viability and decreases the activation of RET-MAPK signaling pathways in EOC cells expressing oncogenic RET mutants.ConclusionsThe discovery of RET pathogenic variants in the EOC patients, suggests a previously underestimated role for RET in EOC tumorigenesis. The identification of the gain-of-function RET mutations in EOC highlights the potential use of RET in targeted therapy to treat ovarian cancer patients.