Browsing by Subject "Ovarian Cancer"

Now showing 1 - 6 of 6
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    Activation of hedgehog signaling is not a frequent event in ovarian cancers
    (BioMed Central, 2009-11-27) Yang, Ling; He, Jing; Huang, Shuhong; Zhang, Xiaoli; Bian, Yuehong; He, Nonggao; Zhang, Hongwei; Xie, Jingwu; Pediatrics, School of Medicine
    The hedgehog (Hh) signaling pathway regulates many processes of development and tissue homeostasis. Activation of hedgehog signaling has been reported in about 30% of human cancer including ovarian cancer. Inhibition of hedgehog signaling has been pursued as an effective strategy for cancer treatment including an ongoing phase II clinical trial in ovarian cancer. However, the rate of hedgehog signaling activation in ovarian cancer was reported differently by different groups. To predict the successful for future clinical trials of hedgehog signaling inhibitors in ovarian cancer, we assessed hedgehog pathway activation in 34 ovarian epithelial tumor specimens through analyses of target gene expression by in-situ hybridization, immunohistochemistry, RT-PCR and real-time PCR. In contrast to previous reports, we only detected a small proportion of ovarian cancers with hedgehog target gene expression, suggesting that identification of the tumors with activated hedgehog signaling activation will facilitate chemotherapy with hedgehog signaling inhibitors.
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    EGFL6 regulates the asymmetric division, maintenance and metastasis of ALDH+ ovarian cancer cells
    (American Association for Cancer Research, 2016-11-01) Bai, Shoumei; Ingram, Patrick; Chen, Yu-Chih; Deng, Ning; Pearson, Alex; Niknafs, Yashar; O'Hayer, Patrick; Wang, Yun; Zhang, Zhong-Yin; Boscolo, Elisa; Bischoff, Joyce; Yoon, Euisik; Buckanovich, Ronald J; Biochemistry and Molecular Biology, School of Medicine
    Little is known about the factors that regulate the asymmetric division of cancer stem-like cells. Here we demonstrate that EGFL6, a stem cell regulatory factor expressed in ovarian tumor cells and vasculature, regulates ALDH+ ovarian cancer stem-like cells (CSC). EGFL6 signaled at least in part via the oncoprotein SHP2 with concomitant activation of ERK. EGFL6 signaling promoted the migration and asymmetric division of ALDH+ ovarian CSC. As such, EGFL6 increased not only tumor growth but also metastasis. Silencing of EGFL6 or SHP2 limited numbers of ALDH+ cells and reduced tumor growth, supporting a critical role for EGFL6/SHP2 in ALDH+ cell maintenance. Notably, systemic administration of an EGFL6-neutralizing antibody we generated restricted tumor growth and metastasis, specifically blocking ovarian cancer cell recruitment to the ovary. Together, our results offer a preclinical proof of concept for EGFL6 as a novel therapeutic target for the treatment of ovarian cancer.
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    Epigenetic Targeting of Adipocytes Inhibits High-Grade Serous Ovarian Cancer Cell Migration and Invasion
    (American Association for Cancer Research, 2018-08) Tang, Jessica; Pulliam, Nicholas; Özeş, Ali; Buechlein, Aaron; Ding, Ning; Keer, Harold; Rusch, Doug; O’Hagan, Heather; Stack, M. Sharon; Nephew, Kenneth P.; Medical and Molecular Genetics, School of Medicine
    Ovarian cancer (OC) cells frequently metastasize to the omentum and adipocytes play a significant role in ovarian tumor progression. Therapeutic interventions targeting aberrant DNA methylation in ovarian tumors have shown promise in the clinic but the effects of epigenetic therapy on the tumor microenvironment are understudied. Here, we examined the effect of adipocytes on OC cell behavior in culture and impact of targeting DNA methylation in adipocytes on OC metastasis. The presence of adipocytes increased OC cell migration and invasion and proximal and direct co-culture of adipocytes increased OC proliferation alone or after treatment with carboplatin. Treatment of adipocytes with hypomethylating agent guadecitabine decreased migration and invasion of OC cells towards adipocytes. Subcellular protein fractionation of adipocytes treated with guadecitabine revealed decreased DNA methyltransferase 1 (DNMT1) levels even in the presence of DNA synthesis inhibitor, aphidicolin. Methyl-Capture- and RNA-sequencing analysis of guadecitabine-treated adipocytes revealed derepression of tumor suppressor genes and EMT inhibitors. SUSD2, a secreted tumor suppressor downregulated by promoter CpG island methylation in adipocytes, was upregulated after guadecitabine treatment, and recombinant SUSD2 decreased OC cells migration and invasion. Integrated analysis of the methylomic and transcriptomic data identified pathways associated with inhibition of matrix metalloproteases and fatty acid α-oxidation suggesting a possible mechanism of how epigenetic therapy of adipocytes decreases metastasis. In conclusion, the effect of DNMT inhibitor on fully differentiated adipocytes suggests that hypomethylating agents may impact the tumor microenvironment to decrease cancer cell metastasis.
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    ETS1 induction by the microenvironment promotes ovarian cancer metastasis through focal adhesion kinase
    (Elsevier, 2018-02-01) Tomar, Sunil; Plotnik, Joshua P.; Haley, James; Scantland, Joshua; Dasari, Subramanyam; Sheikh, Zahir; Emerson, Robert; Lenz, Dean; Hollenhorst, Peter C.; Mitra, Anirban K.; Pathology and Laboratory Medicine, School of Medicine
    Metastatic colonization involves paracrine/juxtacrine interactions with the microenvironment inducing an adaptive response through transcriptional regulation. However, the identities of transcription factors (TFs) induced by the metastatic microenvironment in ovarian cancer (OC) and their mechanism of action is poorly understood. Using an organotypic 3D culture model recapitulating the early events of metastasis, we identified ETS1 as the most upregulated member of the ETS family of TFs in metastasizing OC cells as they interacted with the microenvironment. ETS1 was regulated by p44/42 MAP kinase signaling activated in the OC cells interacting with mesothelial cells at the metastatic site. Human OC tumors had increased expression of ETS1, which predicted poor prognosis. ETS1 regulated OC metastasis both in vitro and in mouse xenografts. A combination of ChIP-seq and RNA-seq analysis and functional rescue experiments revealed FAK as the key transcriptional target and downstream effector of ETS1. Taken together, our results indicate that ETS1 is an essential transcription factor induced in OC cells by the microenvironment, which promotes metastatic colonization though the transcriptional upregulation of its target FAK.
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    A Rationally Designed Histone Deacetylase Inhibitor with Distinct Antitumor Activity against Ovarian Cancer
    (Elsevier, 2009-06) Yang, Ya-Ting; Balch, Curt; Kulp, Samuel K.; Mand, Michael R.; Nephew, Kenneth P.; Chen, Ching-Shih; Medicine, School of Medicine
    Histone deacetylase inhibitors (HDACIs) are a class of antineoplastic agents previously demonstrating preclinical chemosensitizing activity against drug-resistant cancer cells and mouse xenografts. However, whereas clinical studies have shown efficacy against human hematologic malignancies, solid tumor trials have proved disappointing. We previously developed a novel HDACI, “OSU-HDAC42,” and herein examine its activity against ovarian cancer cell lines and xenografts. OSU-HDAC42, (i) unlike most HDACIs, elicited a more than five-fold increase in G2-phase cells, at 2.5 µM, with G2 arrest followed by apoptosis; (ii) at 1.0 µM, completely repressed messenger RNA expression of the cell cycle progression gene cdc2; (iii) at low doses (0.25–1.0 µM for 24 hours), induced tumor cell epithelial differentiation, as evidenced by morphology changes and a more than five-fold up-regulation of epithelium-specific cytokeratins; (iv) potently abrogated the growth of numerous ovarian cancer cells, with IC50 values of 0.5 to 1.0 µM, whereas also remaining eight-fold less toxic (IC50 of 8.6 µM) to normal ovarian surface epithelial cells; and (v) chemosensitizated platinum-resistant mouse xenografts to cisplatin. Compared with the clinically approved HDACI suberoylanilide hydroxamic acid (vorinostat), 1.0 µM OSU-HDAC42 was more biochemically potent (i.e., enzyme-inhibitory), as suggested by greater gene up-regulation and acetylation of both histone and nonhistone proteins. In p53-dysfunctional cells, however, OSU-HDAC42 was two- to eight-fold less inductive of p53-regulated genes, whereas also having a two-fold higher IC50 than p53-functional cells, demonstrating some interaction with p53 tumor-suppressive cascades. These findings establish OSU-HDAC42 as a promising therapeutic agent for drug-resistant ovarian cancer and justify its further investigation.
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    Role of ovarian cancer-initiating cells in high-grade serous ovarian carcinogenesis
    (2012-03-20) Jadhav, Rohit; Zhou, Yaoqi; Nephew, Kenneth P.; Li, Lang; Shen, Changyu; Perumal, Narayanan B.
    A subpopulation of tumor cells known as ovarian cancer initiating cells (OCICs) have been shown to be the cells that propagate the tumor phenotype in ovarian cancer. Studies have showed that a very small population (100) of these cells is sufficient to induce a tumor phenotype; while a large quantity of tumor cells (5 X 105) are required to induce such a phenotype. In this study we studied the functional changes in genes expressed in the OCIC phenotype which were important for such efficient propagation of cancers. To enable this analysis, we generated mRNA expression and DNA methylation profiles of OCICs and compared them with those of tumor and normal ovarian surface epithelial cells. We identified four pathways which regulated most of the observed changes and were predicted to be important factors in distinguishing the OCICs from tumors and normal cells. The gene signatures for these pathways were analyzed by unsupervised clustering in order to determine the similarities of OCICs with respect to tumor and normal samples. We further believed that the OCICs can be used as indicators towards the genesis and progression of early events in the ovarian cancers. In light of this, we considered two hypotheses which are currently addressing the genesis of ovarian cancer. The first hypothesis proposed ovarian surface epithelial cells to be cells of origin of the ovarian cancer while the other proposed the fallopian tube cells to be contributing the cell of origin for these cancers. It is also believed that these two cells can be reciprocal cells of origin for the cancer phenotype. In order to test these hypotheses, we integrated the in-house dataset with a public domain fallopian tube gene expression data. The integration of the results obtained from these analyses provided better understanding of the early events in ovarian carcinogenesis.