Genes In Ovarian Cancer Cells Research Articles

Cancer-associated Fibroblasts-derived Exosomes with HOXD11 Overexpression Promote Ovarian Cancer Cell Angiogenesis Via FN1.

Cancer-associated fibroblasts (CAFs) represent a critical stromal component of metastatic niche and promote metastasis in patients with ovarian cancer (OC). Here, we try to further understand the mechanism by which CAFs-derived exosomes (CAFs-Exo) promoted angiogenesis in OC. We intersected differentially expressed genes in OC cells after CAFs-Exo treatment in the GSE147610 dataset with a list of transcription factors to identify homeobox protein hox-D11 (HOXD11) as a possible cargo of CAFs-Exo. HOXD11 encapsulated by CAFs-Exo enhanced colony formation, migration, and invasion of OC cells. HOXD11 bound to the promoter of fibronectin (FN1) and promoted its transcription. HOXD11 knockdown from CAFs-Exo significantly repressed the VEGF and CD31 protein expression and tube formation, viability, and migration of human umbilical vein endothelial cells (HUVEC) and slowed angiogenesis and tumor growth in mice. Furthermore, we found that overexpression of FN1 increased the expression of angiogenic factors and activity of HUVEC in the presence of HOXD11 knockdown. These results verify the significant contribution of CAFs-Exo to angiogenesis in OC, which could be partially due to the promotion of FN1 mediated by HOXD11.

Study on the Function and Mechanism of miR-585-3p Inhibiting the Progression of Ovarian Cancer Cells by Targeting FSCN1 to Block the MAPK Signaling Pathway

Ovarian cancer (OC) is the leading cause of death for women diagnosed with gynecological cancer. Studies have shown that dysregulated miRNA expression is related to various cancers, including OC. Here, we aimed to explore the biological function and mechanism of miR-585-3p in the occurrence and development of OC. The expression level of miR-585-3p was found to be low in OC tissues and cells. We analyzed the biological function of miR-585-3p in OC through in vitro cell experiments. The results indicated that overexpression of miR-585-3p inhibited the proliferation, invasion, and migration of SW626 cells, while low expression of miR-585-3p had the opposite effect in SKOV3 cells. We then screened the target genes of miR-585-3p through miRDB database and detected the expression of target genes in OC cells. FSCN1 was found to be most significantly upregulated in OC cells. Dual-luciferase reporter assays revealed FSCN1 as a potential target of miR-585-3p. Western blot analysis showed that miR-585-3p targeted FSCN1 to inhibit protein phosphorylation of ERK. In vivo animal experiments also confirmed that miR-585-3p targets FSCN1 to inhibit tumor growth and block the MAPK signaling pathway. In summary, miR-585-3p inhibits the proliferation, migration, and invasion of OC cells by targeting FSCN1, and its mechanism of action may be achieved by inhibiting the activation of the MAPK signaling pathway. miR-585-3p may serve as a potential biomarker and therapeutic target for OC.

A RNAi screening to identify novel targets in cisplatin‐resistant ovarian cancer

Ovarian cancer ranks 5th in cancer-related deaths among women around the world. According to the American Cancer Society, it is estimated that for 2020, there will be 21,750 newly diagnosed ovarian cancer women and 13,940 related deaths in the US alone. Around 94% of ovarian cancer patients survive five years after diagnosis when the disease is detected at an early stage. However, less than 45% of women patients survive when this disease is diagnosed at advanced stages. Currently, there is no effective therapy for ovarian cancer patients, in particular for those that become resistant to chemotherapy (cisplatin). Thus, we need to identify novel targets for ovarian cancer therapy. We performed RNA deep sequencing studies in cisplatin-sensitive and cisplatin-resistant ovarian cancer cells. Several RNA (messengers and long non-coding) were differentially abundant in cisplatin-resistant versus cisplatin sensitive cells. Many of these RNAs have not been previously studied in ovarian cancer. Therefore, we performed rigorous bioinformatic studies that included data filtering and survival rates (using Kaplan-Meier Plot Analysis) and IPA (Ingenuity Pathway Analysis) to select essential candidate genes that can be used as potential targets for ovarian cancer therapy. Additional data filtering was used to choose a list of candidate genes whose expression correlates with the overall survival and progression-free survival of ovarian cancer patients. Twenty-seven resulting genes from our bioinformatics analysis were further evaluated by performing a small-interfering RNA (siRNA)-mediated silencing and cell growth/proliferation assays in cisplatin-resistant ovarian cancer cell lines. Future experiments will investigate the biological consequences of targeting each of these candidate genes in ovarian cancer cells and ovarian cancer mouse models.

Oleuropein reduces cisplatin resistance in ovarian cancer by targeting apoptotic pathway regulators

AimsDespite many attempts to treat ovarian cancer, 13,940 individuals perish annually due to this disease worldwide. Chemotherapy is the main approach to ovarian cancer treatment, but the development of drug resistance is a major obstacle to the successful treatment. Oleuropein is a phenolic ingredient with anticancer characteristics. This study was aimed at investigating the effect of oleuropein on cell viability, cisplatin resistance, and apoptosis, as well as the expression levels of miR-34a, miR-125b, miR16, miR-21, and some of their potential target genes in ovarian cancer cells. Main methodsA2780S and A2780/CP cell lines were exposed to different concentrations of oleuropein alone or in combination with cisplatin for 48 h and 72 h. After that, the cell viability and apoptosis were evaluated using MTT assay and flow cytometry, respectively. Bioinformatics analyses were conducted using STRING database and Cytoscape software. The effect of oleuropein and/or cisplatin on the expression of miRNAs and target genes was assessed via Real-time PCR. Key findingsUpon treatment with oleuropein, the expression of P21, P53, and TNFRSF10B increased while that of Bcl-2 and Mcl1 decreased. Moreover, this is the 1st report of a significant decrease in the expression of miR-21 and increase in the expression of miR-34a, miR-125b, and miR16 by oleuropein and/or cisplatin in ovarian cancer cells. SignificanceAltogether, these data revealed that oleuropein regulated the expression of the above-mentioned miRNAs in ovarian cancer cells, which potentially resulted in apoptosis induction, cell proliferation inhibition, and cisplatin resistance decline in ovarian cancer cells. To confirm the results of this study, it is suggested that similar experiments be performed in animal models of ovarian cancer.

Identification of differentially expressed genes and biological pathways in sanguinarine-treated ovarian cancer by integrated bioinformatics analysis

Aim: This study was intended to identify potentially target genes and underlying biological pathway of sanguinarine in ovarian cancer. Methods: We obtained the expression changes of downstream target genes and underlying biological pathways regulated by control and sanguinarine groups via Affymetrix gene expression profile chip in ovarian cancer cells. An Affymetrix Genechip Agilent mRNA Array was used to recognize differentially expressed genes (DEGs). Afterward, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed for the DEGs using the DAVID database. Results: A total of 1185 DEGs between sanguinarine and control groups were identified, including 835 upregulated and 350 downregulated DEGs. The result of GO analysis recommended that the DEGs were mostly enriched in biological processes, including negative regulation of gene expression, nitrogen compound metabolic process, and transcription from RNA polymerase II promoter. Alterations in cellular components (CC) were suggestively enriched in the cytoskeleton and endoplasmic reticulum. The changes in molecular function were suggestively enriched in nucleic acid-binding transcription factor activity, protein dimerization activity, and enzyme binding. The results of the KEGG pathway analysis indicated that the DEGs were mostly concentrated in “Systemic lupus erythematosus,” “MAPK signalling pathway,” “Pathways in cancer,” and “Metabolic pathways.” Conclusion: The present study provided insights into the mechanism underlying sanguinarine target genes in ovarian cancer cells, which might be used as effective targets for OC diagnosis and treatment.

BCL7C suppresses ovarian cancer growth by inactivating mutant p53.

B-cell CLL/lymphoma 7 protein family member C (BCL7C) located at chromosome 16p11.2 shares partial sequence homology with the other two family members, BCL7A and BCL7B. Its role in cancer remains completely unknown. Here, we report our finding of its tumor-suppressive role in ovarian cancer. Supporting this is that BCL7C is downregulated in human ovarian carcinomas, and its underexpression is associated with unfavorable prognosis of ovarian cancer as well as some other types of human cancers. Also, ectopic BCL7C restrains cell proliferation and invasion of ovarian cancer cells. Consistently, depletion of BCL7C reduces apoptosis and promotes cell proliferation and invasion of these cancer cells. Mechanistically, BCL7C suppresses mutant p53-mediated gene transcription by binding to mutant p53, while knockdown of BCL7C enhances the expression of mutant p53 target genes in ovarian cancer cells. Primary ovarian carcinomas that sustain low levels of BCL7C often show the elevated expression of mutant p53 target genes. In line with these results, BCL7C abrogates mutant p53-induced cell proliferation and invasion, but had no impact on proliferation and invasion of cancer cells with depleted p53 or harboring wild-type p53. Altogether, our results demonstrate that BCL7C can act as a tumor suppressor to prevent ovarian tumorigenesis and progression by counteracting mutant p53 activity.

Abstract 130: CpG binding protein promotes cell proliferation through H3K4 methylation in ovarian cancer

Abstract E3 ubiquitin ligase CRL4 complex activation requires cullin neddylation. MLN4924, a NEDD8-activating enzyme (NAE) inhibitor, reportedly blocked cullin neddylation and inactivated cullin (CUL)-RING E3 ligases (CRLs). Studies have shown that MLN4924 inhibits cell proliferation and survival. We examined the oncostatic and cytotoxic properties of MLN4924 in ovarian cancer. MLN4924 blocked human cancer cell proliferation in nude mice by inhibiting CpG binding protein CFP1 expression. Loss of CFP1 reduced cell growth, promoted apoptosis, and increased senescence. CFP1-dependent H3K4 trimethylation is necessary to maintain the expression of target genes in ovarian cancer cells. We identified bone marrow stromal cell antigen 2 (BST2) and noggin (NOG) as direct targets of CFP1. Their expression was selectively induced by CFP1 deletion. Furthermore, deletion of NOG and overexpression of BST2 prevented the growth-inhibitory effect of CFP1 loss. Our study further demonstrated that CRL4 inactivation reduced CFP1 transcription and trimethylation on lysine 4 of histone H3, which in turn inhibited cell proliferation and induced apoptosis. Therefore, CRL4 constitutes a druggable target in ovarian cancer. Citation Format: Liu-qing Yang, Han-yin Hu, Yao Han, Heng-Yan Zhu, Xiao-min Wang, Lei Ao, Ying Xu, Xuan Huang, Xuan Che, Li-Zhong Wang, Ya-Bo Jiang, Chun-wei Xu, Shu-Qun Cheng, Michal Heger, Wei-wei Pan. CpG binding protein promotes cell proliferation through H3K4 methylation in ovarian cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 130.

Abstract 2232: A novel immune checkpoint regulator in the ovarian cancer microenvironment

Abstract High-grade serous ovarian cancer (HGSC) is the most lethal gynecologic malignancy, accounting for 70-80% of ovarian cancer deaths worldwide. Despite promising results with platinum-based chemotherapy and cytoreductive surgery, more than 75% of women with HGSC will relapse after completion of first-line therapy. The window of opportunity to tailor therapeutic interventions to control progressive disease is limited due to the inherent tumor heterogeneity and genomic instability of HGSC and to how these factors contribute to different immune responses. Recent studies show that biomarkers expressed by specific stromal cell types in the tumor microenvironment may have prognostic value. Our group and others has shown that CD8+ lymphocyte infiltration in the ovarian tumor epithelium is associated with prolonged survival in patients with HGSC. Nevertheless, the molecular mechanisms underlying the promotion or inhibition of CD8+ lymphocyte infiltration by stromal cells in ovarian cancer are not fully understood.By laser microdissection and transcriptome profiling of tumor tissue samples from HGSC patients, we identified stromal cancer associated fibroblasts (CAF)-specific gene signatures that are associated with the survival of patients and with the differential tumor immune response. Among the differentially expressed genes identified, validation study by qPCR, Imaging CyTOF and immunohistochemistry indicated a significant inverse correlation between stromal MFAP5 expression and intratumoral granzyme B+/CD8+ T cell density in HGSC tissue samples. MFAP5 is an extracellular matrix glycoprotein and an important component in the assembly of microfibrils. Moreover our recent studies showed that increased stromal MFAP5 expression is associated with poorer survival in HGSC patients. This led to the hypothesis that MFAP5 could acts as an immune checkpoint mediator by generating an immunosuppressive environment through suppressing CD8+ T cell activation and trafficking in the ovarian tumor tissue. To test this hypothesis, transcriptome profile was performed to identify alteration in immune related genes in ovarian cancer cells treated with rMFAP5. The results showed markedly higher expression of CD47, a novel immune checkpoint molecule that triggers “don't eat me” signals on macrophages, in rMFAP5 treated ovarian cancer cells and CD8+ T cells than control cells. Additionally, we demonstrated that rMFAP5 induced apoptosis in CD8+ T cells and reduced macrophage phagocytosis potential. These data suggest that CD47 mediates the effect of MFAP5 on inducing apoptosis in CD8+ T-cells as wells as on preventing macrophage phagocytosis of ovarian cancer cells.Overall, the identification of MFAP5 as a novel stroma-derived immunomodulatory molecule that is associated with patient survival rates and CD8+ T cell densities presents a unique opportunity for the development of new treatment strategies that may improve survival. Citation Format: Sammy Ferri Borgogno, Tsz-Lun Yeung, Cecilia S. Leung, Chi Lam Au Yeung, Ying Zhu, Stephen T. Wong, Samuel C. Mok. A novel immune checkpoint regulator in the ovarian cancer microenvironment [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2232.

Abstract A57: Identification of novel targets for ovarian cancer treatment

Abstract Ovarian cancer remains one of the most lethal diseases for the female reproductive system with 22,530 new cases and more than 13,980 deaths predicted for 2019 in the United States alone, according to the American Cancer Society. Currently, there is no effective therapy for ovarian cancer patients, in particular for those who become resistant to chemotherapy (cisplatin). We need to identify novel targets for ovarian cancer therapy. We performed RNA deep-sequencing studies in cisplatin-sensitive and cisplatin-resistant ovarian cancer cells. Several RNA (messengers and long noncoding) were differentially abundant in cisplatin-resistant versus cisplatin-sensitive cells. Many of these RNAs have not been previously studied in ovarian cancer. Therefore, we performed rigorous bioinformatic studies that included data filtering and survival rates (using Kaplan-Meier plot analysis) and IPA (Ingenuity Pathway Analysis) to select key candidate genes that can be used as potential targets for ovarian cancer therapy. Additional data filtering was used to select a list of candidate genes whose expression correlates with the overall survival and progression-free survival of ovarian cancer patients. Future experiments will investigate the biologic consequence of targeting each of these candidate genes in ovarian cancer cells and ovarian cancer mouse models. Citation Format: Ricardo Noriega, Jeyshka Reyes, Blanca Quiñones, Joseline Serrano, Pablo Vivas, Josué Pérez. Identification of novel targets for ovarian cancer treatment [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 A57.

Systematic prediction of key genes for ovarian cancer by co-expression network analysis.

Ovarian cancer (OC) is the most lethal gynaecological malignancy, characterized by high recurrence and mortality. However, the mechanisms of its pathogenesis remain largely unknown, hindering the investigation of the functional roles. This study sought to identify key hub genes that may serve as biomarkers correlated with prognosis. Here, we conduct an integrated analysis using the weighted gene co‐expression network analysis (WGCNA) to explore the clinically significant gene sets and identify candidate hub genes associated with OC clinical phenotypes. The gene expression profiles were obtained from the MERAV database. Validations of candidate hub genes were performed with RNASeqV2 data and the corresponding clinical information available from The Cancer Genome Atlas (TCGA) database. In addition, we examined the candidate genes in ovarian cancer cells. Totally, 19 modules were identified and 26 hub genes were extracted from the most significant module (R 2 = .53) in clinical stages. Through the validation of TCGA data, we found that five hub genes (COL1A1, DCN, LUM, POSTN and THBS2) predicted poor prognosis. Receiver operating characteristic (ROC) curves demonstrated that these five genes exhibited diagnostic efficiency for early‐stage and advanced‐stage cancer. The protein expression of these five genes in tumour tissues was significantly higher than that in normal tissues. Besides, the expression of COL1A1 was associated with the TAX resistance of tumours and could be affected by the autophagy level in OC cell line. In conclusion, our findings identified five genes could serve as biomarkers related to the prognosis of OC and may be helpful for revealing pathogenic mechanism and developing further research.

Abstract B045: A novel immune checkpoint regulator in the ovarian cancer microenvironment

Abstract High-grade serous ovarian cancer (HGSC) is the most lethal gynecologic malignancy, accounting for 70–80% of ovarian cancer deaths worldwide. Despite promising results with platinum-based chemotherapy and cytoreductive surgery, more than 75% of women with HGSC will relapse after completion of first-line therapy. The window of opportunity to tailor therapeutic interventions to control progressive disease is limited due to the inherent tumor heterogeneity and genomic instability of HGSC and to how these factors contribute to different immune responses. Recent studies show that biomarkers expressed by specific stromal cell types in the tumor microenvironment may have prognostic value. CD8+ tumor-infiltrating lymphocytes are associated with improved overall survival and have been described in several solid tumors, including HGSC. Nevertheless, the molecular mechanisms underlying the promotion or inhibition of CD8+ lymphocyte infiltration by stromal cells in ovarian cancer are not fully understood. By laser microdissection and transcriptome profiling of tumor tissue samples from HGSC patients, we identified stromal cancer associated fibroblasts (CAF)-specific gene signatures for ovarian cancer that are associated with the survival of patients and with the differential tumor immune response. Among the differentially expressed genes identified, validation study by qPCR, Imaging CyTOF and immunohistochemistry indicated a significant inverse correlation between stromal MFAP5 expression and intratumoral CD8+ T cell density in HGSC tissue samples. MFAP5 is an extracellular matrix glycoprotein and an important component in the assembly of microfibrils. Moreover our recent studies showed that increased stromal MFAP5 expression is associated with poorer survival in HGSOC patients. This led to the hypothesis that MFAP5 could acts as an immune checkpoint mediator by generating an immunosuppressive environment through suppressing CD8+ T cell activation and trafficking in the ovarian tumor tissue. To test this hypothesis, transcriptome profile was performed to identify alternation in immune related genes in ovarian cancer cells treated with rMFAP5. The results showed markedly higher CD47 expression in rMFAP5 treated cells than control cells. CD47 is an integral membrane protein, in both cancer cells and CD8+ T cells. It has been demonstrated to induce apoptosis in CD8+ T cells and trigger inhibitory signals on macrophages to prevent phagocytosis of cancer cells, thus disabling the possibility to activate CD8+ T-cells. We therefore hypothesize that CD47 mediates the effect of MFAP5 on inducing apoptosis in CD8+ T-cells as wells as on preventing macrophage phagocytosis of ovarian cancer cells. Overall, the identification of MFAP5 as a novel stroma-derived immunomodulatory molecule that is associated with patient survival rates and CD8+ T cell densities presents a unique opportunity for the development of new treatment strategies that may improve survival. Citation Format: Sammy Ferri Borgogno, Tsz-Lun Yeung, Cecilia S Leung, Chi Lam Au Yeung, Ying Zhu, Stephen T Wong, Samuel C Mok. A novel immune checkpoint regulator in the ovarian cancer microenvironment [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 B045. doi:10.1158/1535-7163.TARG-19-B045

Abstract 2419: Genome-wide profiling of PAK4 DNA-binding sites and transcriptome reveals its potential transcriptional control on DNA repair-related genes in ovarian cancer cells

Abstract Oncogenic role of p21-activated protein 4 (PAK4) in relation to cell growth and migration through various signalling cascades has been well studied in multiple cancer types. Such role might be contributed largely by cytoplasmic PAK4 as most of the known PAK4 signalling events occur in the cytoplasm. However, recent studies have demonstrated that PAK4 is capable of shuttling between nucleus and cytoplasm. The precise function of nuclear PAK4 (nPAK4) remains substantially unexplored. We have previously shown that PAK4 can act as a transcription factor. Herein, we aim to identify nPAK4-regulated genes by delineating the PAK4-binding landscape in ovarian cancer genome and mapping the PAK4 transcriptome in ovarian cancer cells. PAK4-enriched genomic regions were identified by chromatin immunoprecipitation with a PAK4 antibody followed by next-generation sequencing (ChIP-seq) in OVCAR3 cells. PAK4 transcriptome data was generated using RNA extracted from SKOV3 cells stably expressing PAK4 in the Affymetrix GeneChIP® Human Transcriptome Array 2.0 system. Gene lists generated from both ChIP-seq and microarray dataset were subjected to pathway enrichment analysis by Partek® PathwayTM. Among the 20 most significantly enriched pathways from microarray studies, several pathways in which PAK4 has no known reported function by far have been identified. Notably, DNA repair pathways that are known to influence drug chemosensitivity in ovarian cancer, such as the nucleotide excision repair (p=0.008), homologous recombination (p=0.012), mismatch repair (p=0.018) and DNA replication (p=0.018) pathways were significantly enriched. In concordance with the findings, the nucleotide excision repair pathway was also significantly enriched (p<0.006) in the gene list derived from promoter-restricted PAK4 binding sites in the ovarian cancer genome. Among the many candidates that were deregulated by PAK4, cyclin-dependent kinase 7 (CDK7), a core component in the CAK subcomplex crucial to nucleotide excision repair pathway, was further validated. The transcription start site (TSS) of cyclin-dependent kinase 7 (CDK7) was bound by PAK4. CDK7 mRNA expression was upregulated upon PAK4 overexpression. Quantitative-PCR showed downregulated CDK7 mRNA expression upon siRNA-mediated knockdown of PAK4 in OVCAR3 and TUOS3. This study points to the possible role of PAK4 in regulating gene transcription as PAK4 is mapped to several core promoter/TSS regions in the ovarian cancer genome. Our findings also shed light into the potential role of PAK4 in regulating drug chemosensitivity via its transcriptional control on genes implicated in DNA repair pathways. We postulate CDK7 as a direct transcriptional target of PAK4 and thereby contributes to chemoresistance in ovarian cancer cells. Citation Format: Ivy Tsz-Lo Wong, Oscar Gee-Wan Wong, Yiming Qin, Junwen Wang, Annie Nga-Yin Cheung. Genome-wide profiling of PAK4 DNA-binding sites and transcriptome reveals its potential transcriptional control on DNA repair-related genes in ovarian cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2419. doi:10.1158/1538-7445.AM2017-2419

Targeting miR-21-3p inhibits proliferation and invasion of ovarian cancer cells.

MicroRNA-21 is overexpressed in most cancers and has been implicated in tumorigenesis. Accumulating evidence supports a central role for the miR-21 guide strand (miR-21-5p) in ovarian cancer initiation, progression, and chemoresistance. However, there is limited information regarding the biological role of the miR-21 passenger strand (miR-21-3p) in ovarian cancer cells. The aim of this study was to investigate the role of miR-21-3p and its target genes in cisplatin-resistant ovarian cancer cells. Expression profiling of miR-21-5p and miR-21-3p was performed in a panel of cancer cells by qPCR. Colony formation and invasion assays were carried out on ovarian and prostate cancer cells transfected with miR-21-5p and miR-21-3p inhibitors. Dual luciferase reporter assays were used to identify the miR-21-3p target genes in ovarian cancer cells. Our results show that miR-21-5p had higher expression levels compared to miR-21-3p on a panel of cancer cells. Moreover, inhibition of miR-21-5p or miR-21-3p resulted in a significant decrease in ovarian and prostate cancer cell proliferation and invasion. Luciferase reporter assays identify RNA Binding Protein with Multiple Splicing (RBPMS), Regulator of Chromosome Condensation and POZ Domain Containing Protein 1 (RCBTB1), and Zinc Finger protein 608 (ZNF608) as miR-21-3p target genes. SiRNA-induced RBPMS silencing reduced the sensitivity of ovarian cancer cells to cisplatin treatment. Immunohistochemical analyses of serous ovarian cancer patient samples suggest a significant decrease of RBMPS levels when compared to normal ovarian epithelium. Taken together, the data generated in this study suggests a functional role for miR-21-3p in ovarian cancer and other solid tumors.

Placenta derived mesenchymal stem cells (PDMSCs) modulate HIF-1a, VEGF and JunB genes in ovarian cancer cells.

Placenta derived mesenchymal stem cells (PDMSCs) modulate HIF-1a, VEGF and JunB genes in ovarian cancer cells.

Inhibitory effects of lobaplatin on human ovarian cancer and its regulation of apoptosis-related genes in nude mice

Objective To explore the inhibitory effects of lobaplatin and cisplatin and their regulation of apoptosis-related genes in ovarian cancer cells in nude mice. Methods SKOV3 cells were implanted into nude mice.In monotherapy treatment study, the nude mice bearing human SKOV3 cells were randomly divided into control, lobaplatin, and cisplatin groups, with 7 mice in each group. The mice in each group were received corresponding treatment. The volume of tumor and the weight of nude mice were measured three times per week, respectively. Tumor inhibitory rate was calculated. The protein expressions of bax and bcl-2 were detected by flow cytometry. Results The growth inhibitory rate was 47.2% in lobaplatin group and 42.8% in cisplatin group, without significant difference between two groups (P>0.05). The expression of bcl-2 was decreased but the bax was increased in lobaplatin and ciaplatin groups compared to the control group. Conclusions Lobaplatin can significantly inhibit the growth of ovarian cancer cells, induce apoptosis by down-regulation of bcl-2 and up-regulation of bax. Key words: Organoplatinum compounds/pharmacology; Disease models, animal; Ovarian neoplasms/drug therapy; Mice, nude; Neoplasm transplantation; Genes, bcl-2; Gene expression; Apoptosis

Abstract B35: Target discovery: Using VBIM technique to identify carboplatin resistance genes in ovarian cancer cells

Abstract Among gynecological cancers, ovarian cancer is the leading cause of death each year. Women are often diagnosed with an advanced stage of the disease as it is frequently without overt or specific symptoms until late in its development. One of the major chemotherapy drugs used to treat ovarian cancer is carboplatin. Carboplatin was introduced in the late 1980s and has since gained popularity in clinical treatment due to its vastly reduced side-effects compared to its parent compound, cisplatin. Although resistance to carboplatin remains a major barrier to the successful treatment of ovarian cancer, the mechanisms of its resistance are poorly understood. In this study, we used the novel validation-based insertional mutagenesis (VBIM) technique to identify carboplatin resistance genes in ovarian cancer cells and to further confirm and evaluate their role in mediating carboplatin resistance in ovarian cancer cells. In a preliminary screen, we identified three novel proteins whose functions have never been previously linked to carboplatin resistance in ovarian cancer. We name them ovarian cancer carboplatin resistance genes OCCRP-1, 2 and 3. By generating stable A2780 cells in which OCCRP-1 is either overexpressed or knocked down, we confirmed that OCCRP-1 is a carboplatin resistance gene in ovarian cancer cells. Similar work is carrying on for OCCRP-2 and 3 as well. Our study promises to discover novel mechanisms of gene-mediated carboplatin resistance so that reversal or bypass of this resistance in ovarian cancer can be achieved by developing small chemical inhibitors which ultimately will lead to novel therapeutic approaches for ovarian cancer treatment. Citation Format: Han Wei, Tao Lu. Target discovery: Using VBIM technique to identify carboplatin resistance genes in ovarian cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B35.

Abstract IA17: Targeting the methylome for epigenetic resensitization of ovarian cancer

Abstract Women with advanced stage ovarian cancer (OC) have a five-year survival rate of less than 25%. Although most patients respond to platinum-based chemotherapy, relapses are common, leading to platinum-resistant OC, which is uniformly fatal. OC progression is associated with accumulation of epigenetic alterations. In particular, deoxycytosine methylation of CpG islands in promoter regions of tumor suppressor genes (TSGs) plays a prominent role in the development and progression of drug-resistant epithelial OC. We recently demonstrated for the first time in a clinical trial that therapeutic interventions targeting the OC methylome reverse drug resistance and induce meaningful clinical responses. We showed that repetitive low-dose decitabine reactivated silenced genes and restored sensitivity to carboplatin, providing strong clinical and biological support for further study of hypomethylating agents in heavily pre-treated, platinum-resistant ovarian cancer patients. While the FDA-approved demethylating agent decitabine is prone to deamination by cytidine deaminase, SGI-110 (Astex Pharmaceuticals, Inc.), a dinucleotide analogue of decitabine, is more stable, less toxic, and a promising alternative to restoring silenced TSG expression in cancer cells by reversal of DNA methylation. Our preclinical evaluation demonstrated that SGI-110 resensitized platinum-resistant OC cell lines to cisplatin (CDDP) (3-fold reduction in IC50) and reduced the CDDP IC50. SGI-110 treatment induced significant demethylation and subsequent transcriptional derepression of tumor suppressors and differentiation-associated genes in OC cells. SGI-110 alone or in combination with CDDP was well tolerated in non-tumor bearing mice. Significant antitumor activity was observed in mice harboring subcutaneous OC tumors and treated with single SGI-110 and SGI-110 + CDDP treatment in both a biweekly and daily (QD5) regimen. In addition to reducing tumor growth in xenografts, SGI therapy was effective in causing global as well as TSG demethylation and gene reexpression in vivo. Furthermore, the antitumor activity of SGI-110 was associated with reduced chromatin compaction, allowing greater CDDP intercalation into DNA, as assessed by increased DNA platinum adducts in SGI-treated OC cells. The results of our preclinical study support our recently activated clinical trial NCT01696032 using SGI-110 in combination with carboplatin in patients with recurrent, platinum-resistant OC. Clinical specimens (tumor and plasma samples) will be analyzed for epigenetic biomarker changes. We seek to bring forward the new concept of epigenetic targeting in platinum resistant OC by priming the tumors with SGI-110 and set the stage for interventions targeting the OC epigenome, as well as guide and impact the design of future clinical investigations in OC. Citation Format: Kenneth P. Nephew, Daniela Matei, Pietro Taverna, Fang Fang, Jessica Tang, Gavin Choy, John Lyons, Mohammad Azab, Jay Pilrose, John Turchi. Targeting the methylome for epigenetic resensitization of ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr IA17.

Abstract 94: Identifying biomarkers of estrogen response in models of serous ovarian cancer.

Abstract Ovarian cancer is the fifth leading cause of cancer death among women in the United States. Despite advances in treatment for other cancers, ovarian cancer patient prognosis has not improved significantly since the advent of platinum-based chemotherapy. It is a highly heterogeneous disease with at least four distinct histological subtypes: serous, mucinous, endometrioid, and clear cell. However, no subtype- or biomarker-specific therapies are approved for ovarian cancer. Identifying targeted therapies is crucial to improving clinical outcomes. Specific therapies will likely vary based on tumor histology and biomarkers. Expression of estrogen receptor alpha (ER) is a well established biomarker of response to endocrine therapies in breast cancer. Despite the success of anti-estrogen therapies in treating breast cancer, little attention has been given to their potential in ovarian cancer. However, epidemiologic studies show that approximately 70% of epithelial ovarian tumors express ER, particularly serous and endometrioid subtypes, and that estrogen plays a role in ovarian cancer etiology. Further, clinical data suggest that a subset of ovarian cancer patients can be successfully treated with endocrine therapy. We hypothesize that some ovarian tumors require estrogen for growth and that predictive biomarkers will identify patients who will benefit from endocrine therapy. Using cell line models, we examined the response of ovarian cancer cells to estrogen (E2) and anti-estrogens with regard to gene expression and cell proliferation. E2 induces expression of canonical ER target genes (e.g. GREB1) in these cells, suggesting that they are estrogen-responsive. We observe that 4-hydroxytamoxifen and fulvestrant inhibit growth of ovarian cancer cells including the chemo-resistant line PEO4. Gene expression microarray studies identified additional E2-regulated genes in ovarian cancer cells that may be utilized as biomarkers of ER activity. We are expanding our studies to in vivo models (human primary tumor xenografts) to evaluate the role of E2 in driving tumor progression and determine the efficacy of anti-estrogens in treating serous ovarian cancer. There is a critical need for targeted therapies in ovarian cancer. Our studies will determine if endocrine responsiveness correlates with gene expression of specific biomarkers, which may lead to the identification of predictive clinical markers of response to endocrine therapy. Citation Format: Courtney L. Andersen, Matthew J. Sikora, Paul Haluska, Steffi Oesterreich. Identifying biomarkers of estrogen response in models of serous ovarian cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 94. doi:10.1158/1538-7445.AM2013-94

DNA demethylation is superior to histone acetylation for reactivating cancer-associated genes in ovarian cancer cells

To investigate the contributions of histone H3 lysine 9 acetylation and DNA methylation to p16, hMLH1 and MGMT silencing in ovarian cancer cells, we treated three ovarian cancer cell lines with Trichostatin A (TSA) and 5-aza-2'-deoxycytidine and examined the status of mRNA expression, DNA methylation and histone H3 lysine 9 acetylation at the promoter of p16, hMLH1 and MGMT. The results showed that the hypermethylated silenced tumor-related genes in the ovarian cancer cells were characterized by hypoacetylated histone H3 lysine 9. Treatment with TSA resulted in the increase of histone H3 lysine 9 acetylation at the hypermethylated promoter, but with little effects on gene expression. TSA did not contribute to DNA demethylation. 5-aza-2'-deoxycytidine treatment caused DNA demethylation, increased histone H3 lysine 9 acetylation at the hypermethylated promoter and resulted in reactivation of p16, hMLH1 and MGMT. Combined treatments synergistically increased histone H3 lysine 9 acetylation accompanied by the re-expression of the hypermethylated genes. To conclude, in ovarian cancer cells, DNA methylation and histone deacetylation act synergistically for the silencing of cancer-associated genes. DNA demethylation is superior to histone acetylation for reactivating cancer-associated genes.

Abstract 340: Kaempferol inhibits angiogenesis and tumorigenesis by regulating Akt-HIF, cMyc-p21, and ERRα genes

Abstract This study was designed to investigate kaempferol's effects on VEGF expression and angiogenesis in ovarian cancer cells and the underlying mechanisms/pathways responsible for these effects. Kaempferol's effects on VEGF expression in ovarian cancer cells, OVCAR-3 and A2780/CP70, were studied with ELISA and a VEGF promoter reporter assay. In-vitro and in-vivo angiogenesis were studied with human umbilical vein endothelial cells and chicken embryo chorioallantoic membranes, respectively. Expression or phosphorylation of pertinent genes in ovarian cancer cells treated with kaempferol (0-160 µM) was examined with RT-qPCR, western blot, or ELISA as appropriate. To investigate kaempferol's effects on VEGF expression, the expression of certain genes was either enhanced by transfection of plasmid DNA or knocked down by transfection of siRNA, and the resultant effects evaluated by using a VEGF promoter reporter assay or RT-qPCR. Our study found that kaempferol is effective in inhibiting VEGF expression, in-vitro and in-vivo angiogenesis, and in-vivo tumorigenesis at physiologically relevant concentrations (e.g. 40 µM). We further looked into mechanisms/pathways for these effects, and confirmed a role for Akt and HIF-1α in kaempferol's inhibition on VEGF expression. We discovered that a new HIF-1α-independent pathway is also involved in VEGF regulation. Our results showed that kaempferol executes its effects on VEGF expression through regulating ERRα but not PPARGC1A in OVCAR-3 and A2780/CP70 cells. We also identified cMyc/p21 as a novel pathway for kaempferol's inhibitory effects on VEGF expression in ovarian cancer cells. Our study found that kaempferol is effective for angio-prevention in ovarian cancer cells, and new information was obtained on the mechanisms/pathways for kaempferol's effects. As a dietary flavonoid, kaempferol is a good candidate for angio-prevention and primary prevention of ovarian cancers, and it deserves further investigation in animal studies and human trials. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 340.