SKOV3 Ovarian Cancer Cells Research Articles

MicroRNA184 Reverses Cisplatin Resistance in Human Ovarian Cancer Cells by Regulating the Phosphatidylinositol-3-Kinase (PI3K)/Protein Kinase B (AKT) Signaling Pathway

Ovarian cancer is prone to drug resistance, resulting in poor prognosis. microRNA184 plays a role in many diseases such as tumor and inflammation, but whether microRNA184 regulates ovarian cancer cisplatin resistance is unknown. The ovarian cancer SKOV3 cell line and cisplatin-resistant strain cell SKOV3/DDP were cultured and microRNA184 expression was analyzed by Real time PCR. Transfection of microRNA184 siRNA into SKOV3/DDP under ly294002 (PI3K/AKT inhibitor) treatment followed by analysis of cell proliferation by MTT assay, Caspase 3 activity, cell migration by cell scratch assay, levels of Bax and Bcl-2 by Real time PCR and PI3K/AKT signaling by Western blot. microRNA184 expression was significantly increased in SKOV3/DDP cells compared to SKOV3 cells (P < 0.05). microRNA184 siRNA can significantly down-regulate microRNA184 expression in SKOV3/DDP, inhibit cell proliferation, increase Caspase 3 activity, inhibit cell migration, increase Bax expression, decrease Bcl-2 and decrease pAKT expression (P < 0.05). Addition of ly294002 further significantly promoted the above changes (P < 0.05). Targeting microRNA184 can inhibit SKOV3/DDP cell apoptosis by inhibiting PI3K/AKT signaling pathway, decrease tumor cell proliferation and migration, and inhibit the occurrence and development of cisplatin-resistant ovarian cancer.

The role of sodium hydrosulfide in the proliferation and apoptosis of exogenous SB203580 pre-treated human ovarian cancer cells

Purpose: Explore the regulatory function of sodium hydrosulfide (NaHS) on the proliferation and apoptosis of exogenous SB203580 pre-treated human ovarian cancer SKOV3 cells. Methods: SKOV3 cells cultured in vitro were assigned to the control group, NaHS group, SB203580 group, and NaHS combined with SB203580 group. The effects and influences on cell proliferation were detected by MTT assay. Effects on the cell cycle and apoptosis were detected by flow cytometry. Western blot was used to detect the expression of P-p38MAPK. Results: Proliferation of SKOV3 cells were remarkably decreased in the NaHS, SB203580, and NaHS combined with SB203580 groups. Cell quantity in G1 phase and S phase increased and decreased remarkably, respectively. Obviously, cell apoptosis rate was increased in the combination group compared to single-drug treatment groups. P-p38MAPK expression in NaHS group was upregulated by comparing with that in control group, and that was markedly enhanced in the combination group compared to single-drug treatment group. Conclusions: NaHS inhibited proliferation and promoted apoptosis of SKOV3 cells by blocking the p38MAPK signaling pathway. Furthermore, coordination between NaHS and SB203580 regulated the proliferation and apoptosis of SKOV3 cells.

Alpha 3 Integrin Binding Peptide-Functionalized Polymersomes Loading PLK1 Inhibitor Volasertib for Dually Targeted Molecular Therapy of Ovarian Cancer <i>In vivo</i>

Ovarian cancer (OC) is a high-mortality malignancy in women with a five-year survival rate of 30-40%. There is an urgent need to develop high-efficacy and low toxic treatments for OC. Herein, we report a novel strategy that combines α 3 integrin targeted polymersomes (A3-Ps) and targeted molecular drug, polo-like kinase 1 (PLK1) inhibitor volasertib (Vol) for dually targeted molecular therapy of OC in vivo. A3-Ps had good Vol loading of 7.7-8.0 wt.% and small size of 25-32 nm, depending on the density of α3 integrin binding peptide A3. Interestingly, cellular uptake studies using FITC-labeled Vol revealed that A3-Ps with 20% peptide gave 2.3 and 3.3-fold better internalization in SKOV-3 OC cells compared with non-targeted Ps and free Vol, respectively. Accordingly, Vol loaded in A3-Ps showed the best inhibitory activity to SKOV-3 cells with an IC50 of 49 nM, which was 3.5 times lower than free Vol. Importantly, the in vivo experiments demonstrated that A3-Ps-Vol proficiently repressed the growth of SKOV-3 tumors in mice while continuous tumor growth was observed for Ps-Vol and free Vol-treated mice. A3-Ps-Vol besides boosting anti-OC activity also reduced the systemic toxicity of Vol. This dually targeted molecular drug nanoformulation has appeared to be an especially potent and low toxic treatment modality for human ovarian cancers.

P-MAPA and Interleukin-12 Reduce Cell Migration/Invasion and Attenuate the Toll-Like Receptor-Mediated Inflammatory Response in Ovarian Cancer SKOV-3 Cells: A Preliminary Study

Immunotherapies have emerged as promising complementary treatments for ovarian cancer (OC), but its effective and direct role on OC cells is unclear. This study examined the combinatory effects of the protein aggregate magnesium–ammonium phospholinoleate–palmitoleate anhydride, known as P-MAPA, and the human recombinant interleukin-12 (hrIL-12) on cell migration/invasion, apoptosis, toll-like receptor (TLR)-mediated inflammation, and cytokine/chemokine profile in human OC cell line SKOV-3. P-MAPA and IL-12 showed cancer cell toxicity under low doses after 48 h. Although apoptosis/necrosis and the cell cycle were unchanged by the treatments, P-MAPA enhanced the sensitivity to paclitaxel (PTX) and P-MAPA associated with IL-12 significantly reduced the migratory potential and invasion capacity of SKOV-3 cells. P-MAPA therapy reduced TLR2 immunostaining and the myeloid differentiation factor 88 (MyD88), but not the TLR4 levels. Moreover, the combination of P-MAPA with IL-12 attenuated the levels of MyD88, interferon regulatory factor 3 (IRF3) and nuclear factor kappa B (NF-kB p65). The IL-12 levels were increased and P-MAPA stimulated the secretion of cytokines IL-3, IL-9, IL-10, and chemokines MDC/CCL22 and, regulated on activation, normal T cells expressed and secreted (RANTES)/CCL5. Conversely, combination therapy reduced the levels of IL-3, IL-9, IL-10, MDC/CCL22, and RANTES/CCL5. Collectively, P-MAPA and IL-12 reduce cell dynamics and effectively target the TLR-related downstream molecules, eliciting a protective effect against chemoresistance. P-MAPA also stimulates the secretion of anti-inflammatory molecules, possibly having an immune response in the OC microenvironment.

Alkaloid from Colchicum species in complexes with lithium, sodium, potassium and magnesium cations– spectroscopic characterization, semiempirical and theoretical calculation, fungicidal and cytotoxic activity

The colchicine (1:1) complexes with monovalent cations: Li+, Na+ and K+ as well as divalent cation Mg2+ of nitrate salts were synthesized and characterized by 1H and 13C NMR, FT-IR, UV–Vis, ESI-MS, spectroscopic methods and elemental analysis. In the ESI-MS mass spectra (in ES+ mode) formation of complexes of different stoichiometry 1:1, 2:1, 3:1, (colchicine – metal cation) was detected and in complexation process nitrate anions are also involved. Stoichiometry 1:1:1, 1:2:1, 2:1:1 and 2:2:1 (colchicine – metal cation – nitrate anion) of colchicine complexes with nitrate salts were also detected. The structures of the colchicine complexes with Li+, Na+, K+ and Mg2+ cations are discussed in details by PM5 semiempirical calculations, DFT, M06-2X theoretical calculations, molecular dynamics (MD) simulations and molecular modelling. Complexes were also screened against fungicidal and cytotoxic activity. The antifungal activity of colchicine and all complexes was assayed in vitro against eight fungi species. Cytotoxic activity of all complexes was tested against ovarian cancer cell SKOV-3 line.

Abstract C032: A novel integrin-targeted therapeutic agent for ovarian cancer

Abstract No present therapy effectively impacts overall survival of advanced ovarian cancer (OC). The current standard-of-care includes surgical debulking followed by combination intravenous (IV) or intraperitoneal (IP) chemotherapy. Although there is increasing interest in IP chemotherapy, side effects from cytotoxic agents result in a significant percentage of women discontinuing treatment. We propose to examine the efficacy of IP administration of a novel non-cytotoxic, non-immunogenic, anti-invasive peptide called vicrostatin (Mol. Wt. 7,146). We investigated the clinical translational potential of this disintegrin, which was conceived, produced and developed in our laboratory. Vicrostatin is produced recombinantly using a bacterial system in amounts sufficient for clinical trials. It has high binding affinity for a number of RGD (Arg-Gly-Asp)-integrins, including αvβ3, αvβ5, α5β1 and αIIbβ3. Vicrostatin disruption of the actin cytoskeleton, which occurs exclusively in motile cells (cancer and angiogenic endothelial cells), accounts for its mechanism of action. We showed lack of toxicity following vicrostatin introduction into rodents. We used several different experimental animal models to demonstrate the efficacy of vicrostatin in ovarian cancer. We compared saline and Oxiplex formulations for IP delivery of vicrostatin in mouse models. Oxiplex, a hydrogel composed of polyethylene oxide and carboxymethyl cellulose, stabilized by CaCl2, is impregnated with vicrostatin; incorporation of vicrostatin at 2-10 mg/ml results in its sustained release for 10-12 days. We eventually settled on a 5 mg/week (250mg/kg) dose per mouse and compared efficacies of Oxiplex versus saline in animals harboring IP xenografts (10 animals per group) of SKOV3GFP/LUC spheroids (2x106 cell equivalents); the spheroids were allowed to implant for 4 days before treatment with weekly IP injections of either 5 mg of vicrostatin in 1 ml saline, 5mg of vicrostatin in 1 ml of Oxiplex, or 1 ml of Oxiplex alone (control). After one-month animals in Oxiplex alone group showed extensive and widespread cancer cell dissemination based on bioluminescent imaging and findings at autopsy. Vicrostatin-saline and vicrostatin-Oxiplex treatments resulted in dramatically less or, in some animals, no grossly visible tumor foci and in ~95-98% reduction in bioluminescent signals. These results were reproduced in three independent experiments and suggest that both delivery modalities are similarly effective. An advantage of the Oxiplex formulation is its ability to prevent post-surgical adhesions, a frequent complication of gynecological surgery. We are presently using RNAseq technologies to investigate changes in expression of genes involved in intracellular pathways suspected to represent predictive biomarkers of ovarian cancer response to vicrostatin therapy in xenografts of SKOV3 ovarian cancer cells. The results will enhance our understanding of pathways targeted by vicrostatin and provide biomarkers of clinical responsiveness in future clinical trials. Citation Format: Franics S Markland, Steve Swenson, Radu Minea, Louis Dubeau. A novel integrin-targeted therapeutic agent for ovarian cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C032. doi:10.1158/1535-7163.TARG-19-C032

MiR-34a-5p/PD-L1 axis regulates cisplatin chemoresistance of ovarian cancer cells.

Ovarian cancer is the most lethal gynecologic malignancy in women with an increasing number of cases worldwide. Chemoresistance is the main obstacle for ovarian cancer treatment during clinical therapy. Previous studies found that programmed cell death 1 ligand 1 (PD-L1) was associated with chemoresistance of cancer. However, there were little reports about the function of PD-L1 involved in chemoresistance of ovarian cancer. In our study, cisplatin (DDP)-resistant SKOV3 and A2780 ovarian cancer cell lines (SKOV3/DDP and A2780/DDP) were established. We found that the expression of PD-L1 was increased and miR-34a-5p was decreased in DDP-resistant cells. PD-L1 silencing inhibited chemoresistance of DDP-resistant ovarian cancer cells to DDP, as evidenced by decreased proliferation, G1-phase cell cycle arrest and increased apoptosis. Western blot assay showed that in the presence of DDP, PD-L1 silencing decreased multidrug resistance protein 1 and Cyclin D1 protein levels, whereas increased cleaved-caspase-3 and cleaved-PARP protein levels in these cells. Moreover, we demonstrated that miR-34a-5p negatively regulated the expression of PD-L1 by targeting its 3'-untranslated region. The effects of miR-34a-5p mimic on DDP-treated SKOV3/DDP cells were reversed by the overexpression of PD-L1. Moreover, the tumorigenicity of DDP-resistant ovarian cancer cells in nude mice treated with DDP was attenuated by miR-34a-5p in vivo. The combined data indicate that miR-34a-5p/PD-L1 axis regulates DDP chemoresistance of ovarian cancer cells, providing a deeper insight into the treatment for ovarian cancer.

Dually Active Targeting Nanomedicines Based on a Direct Conjugate of Two Purely Natural Ligands for Potent Chemotherapy of Ovarian Tumors.

Actively targeted nanomedicines have promised to revolutionize cancer treatment; however, their clinical translation has been limited by either low targetability, use of unsafe materials, or tedious fabrication. Here, we developed CD44 and folate receptor (FR) dually targeted nanoparticulate doxorubicin (HA/FA-NP-DOX) based on a direct conjugate of two purely natural ligands, hyaluronic acid and folic acid (FA), for safe, highly specific, and potent treatment of ovarian tumors in vivo. HA/FA-NP-DOX had a small size and high DOX loading, wherein the particle size decreased from 115, 93, to 89 nm with increasing degree of substitution of FA from 6.4, 8.5, to 11.1, while increased from 80, 93, to 103 nm with increasing DOX loading from 15.0, 23.1, to 31.4 wt %. Interestingly, HA/FA-NP-DOX exhibited excellent lyophilization redispersibility and long-term storage stability with negligible drug leakage while it released 91% of DOX in 48 h at pH 5.0. Cellular studies corroborated that HA/FA-NP-DOX possessed high selectivity to both CD44 and FR, resulting in strong killing of CD44- and FR-positive SKOV-3 ovarian cancer cells while low toxicity against CD44- and FR-negative L929 fibroblast cells. In vivo studies revealed a long elimination half-life of 5.6 h, an elevated tumor accumulation of 12.0% ID/g, and an effective inhibition of the SKOV-3 ovarian tumor for HA/FA-NP-DOX, leading to significant survival benefits over free DOX·HCl and phosphate-buffered saline controls. These dually targeted nanomedicines are simple and safe, providing a potentially translatable treatment for CD44- and FR-positive malignancies.

Abstract NT-120: KNOCKOUT OF MTF1 RESULTS IN THE INHIBITION OF EMT IN OVARIAN CANCER CELLS

Abstract Due to peritoneal metastasis and frequent recurrence, ovarian cancer has the highest mortality among gynecological cancers. Epithelial to mesenchymal transition (EMT) contributes to ovarian tumor metastasis. In this study, we report for the first time that metal regulatory transcription factor 1 (MTF1) was upregulated in ovarian cancer, and its high expression was associated with poor patient survival and disease relapse. Knockout of MTF1 using lentiviral CRISPR/Cas9 nickase vector-mediated gene editing inhibited EMT by upregulating epithelial cell markers E-cadherin and cytokeratin 7, and downregulating mesenchymal markers Snai2 and β-catenin in ovarian cancer SKOV3 and OVCAR3 cells. Loss of MTF1 reduced cell proliferation, migration, and invasion in both SKOV3 and OVCAR3 cells. Knockout of MTF1 upregulated the expression of the KLF4 transcription factor, and attenuated two cellular survival pathways, ERK1/2 and AKT. Our studies demonstrated that MTF1 plays an oncogenic role and contributes to ovarian tumor metastasis by promoting EMT. MTF1 may be a novel biomarker for early diagnosis as well as a drug target for clinical therapy. Citation Format: Guannan Zhao, Lawrence M Pfeffer Junming Yue. KNOCKOUT OF MTF1 RESULTS IN THE INHIBITION OF EMT IN OVARIAN CANCER CELLS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-120.

Abstract GMM-053: ROLE OF LATS AND DYRK1A KINASES IN THE PATHOGENESIS AND TREATMENT OF HGSOC

Abstract Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy, with 75% of women presenting with metastatic disease at the time of diagnosis. High Grade Serous Ovarian Carcinoma (HGSOC) is the most common and aggressive type of epithelial ovarian cancer, with 5-year survival rate of 30% for most patients. Developing of accurate experimental models of HGSOC is necessary to elucidate the disease pathogenesis and to evaluate new treatments. Our study is aimed at determining the roles of the Large Tumor Suppressor 1 and 2 kinases (LATS1/2), and their downstream effector Dual-specificity tyrosine(Y)-Regulated Protein Kinase 1A (DYRK1A), in HGSOC pathogenesis and treatment sensitivity. The Cancer Genome Atlas study revealed copy number losses of the LATS1, LATS2 and DYRK1A genes in 65%, 59% and 38% of HGSOC cases, respectively. Previous studies found that LATS1/2 and DYRK1A mediate a crosstalk between the Hippo tumor suppressor pathway and the G0/G1 cell cycle checkpoint. However, the role of these kinases in HGSOC pathogenesis is not known. We found that loss of both LATS1 and LATS2, or DYRK1A results in increased proliferation of SKOV3 ovarian cancer cells in 2D or 3D cultures, mediated in part by disruption of the DREAM complex that represses cell cycle-regulated genes. Interestingly, we observed upregulation of cyclin D1 and increased phosphorylation of retinoblastoma (RB) family proteins in SKOV3 cells depleted of LATS1/2 or DYRK1A kinases, indicative of aberrant activation of CDK4/6. Similar changes were observed upon depletion of LATS1/2 or DYRK1A using non-transformed human fallopian epithelial cells, suggesting that genetic losses of these kinases could contribute to the HGSOC pathogenesis. Furthermore, we tested whether an aberrant activation of CDK4/6 in SKOV3 cells with low levels of LATS1/2 or DYRK1A could increase their sensitivity to pharmacological CDK4/6 inhibitors such as palbociclib. Using metabolic cell proliferation assays, we found that loss of LATS1/2 or DYRK1A resulted in a significant decrease of palbociclib IC50 in SKOV3 cells. Interestingly, palbociclib treatment increased the DREAM assembly in these cells, resulting in downregulation of DREAM-regulated cell cycle factors such as cyclin A or B-Myb. Our results show that loss of LATS1/2 or DYRK1A could contribute to HGSOC pathogenesis by CDK4/6-mediated disruption of RB family function. Further studies are underway to validate our findings in vivo using orthotopic ovarian tumor xenografts in mice and a bioluminescence imaging approach. In addition, these models will be used for validation of novel therapeutic approaches for HGSOC, such as palbociclib, as well as for the mechanistic studies of the EOC pathogenesis. Citation Format: Fatmata Sesay, Siddharth Saini, Larisa Litovchick. ROLE OF LATS AND DYRK1A KINASES IN THE PATHOGENESIS AND TREATMENT OF HGSOC [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr GMM-053.

Ovarian Cancer Targeting Phage for In Vivo Near-Infrared Optical Imaging.

Ovarian cancer is often diagnosed at late stages due to current inadequate detection. Therefore, the development of new detection methods of ovarian cancer is needed. This may be achieved by phage nanoparticles that display targeting peptides for optical imaging. Here, two such phage clones are reported. Ovarian cancer binding and specificity of phage clones (pJ18, pJ24) and peptides (J18, J24) were investigated using fluorescent microscopy and modified ELISA. Further, AF680-labeled phage particles were subjected to biodistribution and optical imaging studies in SKOV-3 xenografted mice. Fluorescent microscopy and ELISA of phage and peptides showed significantly increased binding to SKOV-3 cells compared to controls. Additionally, these studies revealed that J18 exhibits specificity for ovarian cancer SKOV-3 and OVCAR-3 cell lines. Further, peptides displayed increased SKOV-3 binding compared to N35 (non-relevant peptide) with EC50 values of 22.2 ± 10.6 μM and 29.0 ± 6.9 (mean ± SE), respectively. Biodistribution studies of AF680-labeled phage particles showed tumor uptake after 4 h and excretion through the reticuloendothelial system. Importantly, SKOV-3 tumors were easily localized by optical imaging after 2 h and 4 h and displayed good tumor-to-background contrast. The fluorescent tumor signal intensity was significantly higher for pJ18 compared to wild type (WT) after 2 h.

Exosomal microRNA-205 is involved in proliferation, migration, invasion, and apoptosis of ovarian cancer cells via regulating VEGFA

BackgroundRecently, the impact of microRNAs (miRNAs) and exosome on ovarian cancer has been assessed in many studies. We aim to explore the mechanism of exosomes transferring miR-205 in ovarian cancer, and confirm its diagnostic value in ovarian cancer.MethodsThe expression of miR-205 of ovarian cancer patients and healthy people was detected by RT-qPCR, and the diagnostic value of miR-205 was evaluated. The exosomes derived from SKOV3 cells were identified. Ovarian cancer SKOV3 donor cells and receptor cells were used to measure the proliferation, migration, invasion, apoptosis and cell cycle by a series of experiments. The binding site between miR-205 and vascular endothelial growth factor A (VEGFA) was evaluated by bioinformatics tool and dual-luciferase reporter gene assay.ResultsMiR-205 was up-regulated in ovarian cancer, and up-regulated miR-205 could enhance the risk of ovarian cancer and was one of its risk factors. After SKOV3 cells-derived exosomes were transiently introduced with miR-205 mimics, the cell proliferation, migration and invasion in ovarian cancer were elevated, the apoptosis of ovarian cancer cells was attenuated, and the epithelial–mesenchymal transition (EMT) protein E-cadherin was down-regulated, while Vimentin was elevated. VEGFA was identified to be a target gene of miR-205.ConclusionThis study suggests that exosomes from donor ovarian cancer cell SKOV3 shuttled miR-205 could participate in the regulation of the proliferation, migration, invasion, apoptosis as well as EMT progression of receptor SKOV3 cells by targeting VEGFA.

Antitumor effect of a short peptide on p53-null SKOV3 ovarian cancer cells.

Fibroblast growth factor-2 (FGF2) is a protein ligand, which exerts essential roles in development, angiogenesis, and tumor progression via activation of the downstream signaling cascades. Accumulating evidence has demonstrated that FGF2 is involved in the progression of ovarian cancer, providing a novel potential target for ovarian cancer therapy. In this study, we showed that FGF2 is significantly increased in ovarian tumors, and is negatively associated with the overall survival of ovarian cancer by database analysis. A short peptide obtained from a heptapeptide phage display library suppressed FGF2-induced proliferation, migration, and invasion of the p53-null epithelial ovarian cancer (EOC) cells. Further investigations revealed that the short peptide antagonized the effects of FGF2 on G0/G1 to S cell phase promotion, cyclin D1 expression, and MAPK and Akt signaling activation, which might contribute to the mechanism underlying the inhibitory effects of the short peptide on the aggressive phenotype of the ovarian cancer cells triggered by FGF2. Moreover, the short peptide might have the potentials of reversing FGF2-induced resistance to the doxorubicin via downregulation of the antiapoptotic proteins and counteracting of the antiapoptotic effects of FGF2 on p53-null EOC cells. Taken together, the short peptide targeting FGF2 may provide a novel strategy for improving the therapeutic efficiency in a subset of EOC.

Effect of umbilical cord mesenchymal stem cells on proliferation and apoptosis of ovarian cancer cells

To observe the effects of human umbilical cord mesenchymal stem cells (UC-MSCs) on the proliferation and apoptosis of human ovarian cancer cell SKOV3. Methods: Transwell co-culture was used to observe the targeted homing effect of UC-MSCs on ovarian cancer cells. MTT assay was used to detect the inhibitory effect of UC-MSCs conditioned medium on SKOV3 proliferation, and Annexin V-FITC/PI double staining was used to detect the apoptotic rate. Real-time PCR was used to detect the expression levels of Ki-67, Bcl-2 and Bax genes-relevant to proliferation and apoptosis of SKOV3 cells. Results: UC-MSCs targeted SKOV3 cells in vitro. MTT assay showed that UC-MSCs conditioned medium significantly inhibited the proliferation of SKOV3 cells (P<0.01). Annexin V-FITC/PI double staining showed that the apoptotic rate in the 75% conditioned medium group was significantly higher than that in the control group (P<0.05). Real-time PCR showed that the expression of proliferation-related gene Ki-67 decreased significantly (P<0.01). The apoptosis-related gene Bcl-2 expression was decreased dramatically (P<0.01), and Bax expression was increased significantly (P<0.01). Conclusion: UC-MSCs can target ovarian cancer cells in vitro, inhibit the proliferation of SKOV3 cells by regulating the expression of Ki-67, and promote the apoptosis of SKOV3 cells by regulating the expression of Bcl-2 and Bax.

Betacellulin enhances ovarian cancer cell migration by up-regulating Connexin43 via MEK-ERK signaling

Epithelial ovarian cancer is the fifth common cause of cancer death in women and the most lethal gynecological malignancies. Our previous studies have shown that up-regulation of Connexin43, a gap-junction subunit crucial for cell-cell communication, enhances ovarian cancer cell migration. Betacellulin is a member of the epidermal growth factor (EGF) family which can bind to multiple EGF family receptors. Overexpression of betacellulin is found in a variety of cancers and is associated with reduced survival. However, the specific roles and molecular mechanisms of betacellulin in ovarian cancer progression are poorly understood. In the current study, we tested the hypothesis that betacellulin induces ovarian cancer cell migration by up-regulating Connexin43. Our results showed that treatment with betacellulin significantly increased Connexin43 expression and cell migration in both OVCAR4 and SKOV3 ovarian cancer cell lines. Moreover, betacellulin induced the activation of MEK-ERK signaling, and its effects on Connexin43 were inhibited by pre-treatment with U0126. Pre-treatment with AG1478 totally blocked the activation of MEK-ERK signaling but only partially inhibited betacellulin-induced Connexin43 expression and cell migration. Most importantly, betacellulin-induced cell migration was attenuated by knockdown of Connexin43, and co-treatment with gap junction inhibitor carbenoxolone did not alter this effect. Our results suggest a bilateral role of Connexin43 in ovarian cancer migration, and also demonstrate a gap junction-independent mechanism of betacellulin.

Asparagine Synthetase and Filamin A Have Different Roles in Ovarian Cancer.

Early-stage ovarian serous carcinoma is usually difficult to detect in clinical practice. The profiling of protein expression in high-grade serous carcinoma (HGSC) and low-grade serous carcinoma (LGSC) would provide important information for diagnoses and chemotherapy. Here, we performed proteomic profiling of specimens from 13 HGSC and 7 LGSC patients by iTRAQ. A total of 323 proteins that were differentially expressed were identified. After immunohistochemical confirmation of expressed proteins in 166 clinical tissues, asparagine synthetase (ASNS) and filamin A (FLNA) were selected for further functional study. Cisplatin-sensitive (CS; ASNShigh and FLNAlow) and cisplatin-resistant (CR; ASNSlow and FLNAhigh) SKOV3 and OVCAR3 ovarian cancer cell lines were used for subsequent in vitro and in vivo experiments. Notably, ASNS overexpression (ASNS+) or FLNA knockdown (shFLNA) enabled cisplatin-induced apoptosis and autophagy in CR cells. However, ASNS+ and shFLNA promoted and attenuated tumor growth, respectively. In CS cells, ASNS knockdown (shASNS) attenuated clonogenicity, cell proliferation, and the epithelial–mesenchymal transition, whereas FLNA overexpression (FLNA+) protected cells from cisplatin. In vivo, cisplatin resistance was attenuated in mice xenografted with ASNS+, shFLNA, or ASNS+-shFLNA CR cells, whereas xenografts of shASNS or FLNA+ CS cells exhibited resistance to cisplatin. Clinically, all HGSC patients (83/83) responded to cisplatin, while 6 in 41 LGSC patients exhibited cisplatin resistance. These findings identify ASNS and FLNA as distinct biomarkers for HGSC and LGSC, which may have potential value in the prognosis and clinical treatment of serous carcinoma.

Isoliquiritigenin Inhibits Ovarian Cancer Metastasis by Reversing Epithelial-to-Mesenchymal Transition.

The epithelial-to-mesenchymal transition (EMT) plays a prominent role in cancer metastasis. Isoliquiritigenin (ISL), one of the flavonoids in licorice, has been shown to exhibit anticancer activities in many cancer types through various mechanisms. However, it is unknown whether ISL impacts the EMT process. Here, we show that ISL is able to suppress mesenchymal features of ovarian cancer SKOV3 and OVCAR5 cells, evidenced by an apparent morphological change from a mesenchymal to an epithelial phenotype and reduced levels of mesenchymal markers accompanied by the gain of E-cadherin expression. The suppression of EMT is also supported by the observed decrease in cell migration and in vitro invasion upon ISL treatment. Moreover, we show that ISL effectively blocks the intraperitoneal xenograft development of the SKOV3 cell line and prolonged the survival of tumor-bearing mice. These data suggest that ISL inhibits intraperitoneal ovary tumor development through the suppression of EMT, indicating that ISL may be an effective therapeutic agent against ovarian cancer.

Effect of progesterone and first evidence about allopregnanolone action on the progression of epithelial human ovarian cancer cell lines

Ovarian carcinoma is one of the most common cause of death by gynecologic cancer. Several epidemiological and in vitro studies have shown controversial data about progesterone effects in ovarian cancer. Progesterone can be converted in its active metabolite, allopregnanolone, its effects in ovarian cancer are still unknown. Previously, we demonstrated that allopregnanolone modifies ovarian morphophysiology, being able to alter critical process of tumor development such as proliferation, apoptosis and angiogenesis. Taking into account these antecedents, we investigated the effect of progesterone and allopregnanolone on proliferation, apoptosis, clonogenic capacity and migration on two epithelial human ovarian cancer cell lines, IGROV-1 and SKOV-3. To this end, IGROV-1 and SKOV-3 cells were exposed to a range of progesterone and allopregnanolone concentrations (10-11 to 10-5 M) for 72 h. Proliferation was analyzed by MTT and Ki67 expression. Apoptosis was measured by immunocytochemistry of cleaved caspase 3. Clonogenic capacity was evaluated by counting colonies. Migration was analyzed by wound assay. We found that allopregnanolone increased proliferation and Ki67 expression respect to control on IGROV-1 cells, while expression of cleaved caspase 3 did not change in any cell line studied. IGROV-1 clonogenic capacity was also increased by allopregnanolone treatment. Both steroids, progesterone and allopregnanolone, increased IGROV-1 migration in a concentration dependent manner. None of the steroids tested modified SKOV-3 biological behavior analized. This is the first evidence that allopregnanolone, a progesterone metabolite, affects critical events in tumor development of human epithelial ovarian cancer. These results could have an impact in the future in clinic diagnosis, prognosis and treatment of ovarian cancer patients. The regulation of progesterone and allopregnanolone steroideogenesis and their molecular mechanisms might be considered as potential therapeutic tool in ovarian cancer.

LncRNA PCAT6 promotes occurrence and development of ovarian cancer by inhibiting PTEN.

The purpose of this study was to explore the expression and function of long non-coding RNA (lncRNA) PCAT6 in ovarian cancer. Quantitative Real-Time-Polymerase Chain Reaction (qRT-PCR) was used to detect the expression of lncRNA PCAT6 in 42 pairs of ovarian cancer tissues and adjacent normal tissues. Then, the relationship between PCAT6 expression and pathological indicators of ovarian cancer was analyzed. Subsequently, the transfection efficiency of PCAT6 in ovarian cancer cells was verified, and the PCAT6 knockdown model was constructed using lentiviruses in SKOV3 and CAOV3 ovarian cancer cell lines. In addition, Cell Counting Kit-8 (CCK-8) test, wound healing assay and transwell invasion and migration experiments were performed to estimate the effect of PCAT6 on the biological function of ovarian cancer cells, to further explore the possible potential mechanisms. QRT-PCR results showed that the expression level of PCAT6 in ovarian cancer was higher than that in the adjacent normal tissues. The incidence of distant metastasis and lymph node metastasis in patients with high expression of PCAT6 was higher than those with low PCAT6 expression. Compared with the NC group, the proliferation, metastasis and invasion ability of ovarian cancer cells in si-PCAT6 group decreased significantly. QRT-PCR results demonstrated that the PTEN expression was increased after the knockdown of PCAT6. In addition, the recovery experiment also revealed that PCAT6 and PTEN have a mutual regulation, which can jointly regulate the development of ovarian cancer. LncRNA PCAT6 was up-regulated in ovarian cancer tissues and was closely related to distant metastasis or lymph node metastasis. Additionally, lncRNA PCAT6 might promote the proliferation, migration and invasion of ovarian tumor cells by inhibiting PTEN.

299P - Activity of BET-proteolysis targeting chimeric (PROTAC) compounds in triple negative breast cancer

BackgroundTriple negative breast cancer (TNBC) is an incurable disease, therefore novel therapies are needed. Bromo and extraterminal domain inhibitors (BETi) are currently in clinical development with promising activity in TNBC. However, resistance to these agents will limit their efficacy. Proteolysis targeting chimeric (PROTAC) are novel compounds that by binding to a ubiquitin ligase promotes protein degradation. MethodsIn our study we explore the antitumoral activity of two BET-PROTACs, MZ1 and ARV-825 in TNBC and ovarian cancer. We used MDAMB-231, BT549 and MDAMB-231 JQ1 resistant TNBC cells lines; and OVCAR3 and SKOV3 ovarian cancer cells lines. We evaluated the antiproliferation effect using MTT assay, colony-forming assay and three-dimensional cultures in Matrigel. To explore the molecular mechanism of drugs we used flow cytometry (cell cycle and cell death). The analysis of protein expression was determined by western blot. In vivo studies included BALB/c nu/nu mice that were injected with MDAMB-231 JQ1 resistant cells and later treated with BETi JQ1 and BET-PROTAC MZ1. ResultsBoth PROTACs efficiently and maintained deleted the levels of BRD4 in MDA-MB-231 and in the resistant JQ1 cell line MDA-MB-231R. MZ1 and ARV-825 showed a profound antiproliferative effect in MDA-MD-231 sensitive and resistant cells using 2D and 3D cultures, and had a similar activity in other triple negative (BT549) and ovarian cancer (SKOV3, OVCAR) cell lines. MZ1 slightly arrested cells at G2/M in sensitive and resistant JQ1 MDA-MB-231 cells. In addition, a profound effect on apoptosis was observed, that was more evident in the sensitive cell line, effect that was caspase dependent. Given the potent antiproliferative activity of MZ1 no synergistic activity was observed when combined with docetaxel, cisplation or olaparib. Finally, administration of MZ1 was able to recue tumor growth in nude mice of MDA-MB-231 JQ1 resistant cells, by reducing the expression of BRD4. ConclusionsWe describe the profound activity of BET-PROTACs in TNBC cell lines and in an in vivo BETi resistant model. This data provides options for further clinical development of these agents in TNBC. Legal entity responsible for the studyThe authors. FundingInstituto de Salud Carlos III (PI16/01121), ACEPAIN; Diputación de Albacete, CIBERONC, CRIS Cancer Foundation, implementation research program of the UCLM System of Science, Technology and Innovation-Secti (co-funded by the European Commission/FSE funds) and scientific foundation of the AECC. DisclosureAll authors have declared no conflicts of interest.