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In normal pregnancy, hepatic metabolism adaptation occurs with an increase in lipid biosynthesis. Placental shedding of syncytiotrophoblast‐derived extracellular vesicles (STBEVs) into the maternal circulation constitutes a major signalling mechanism between foetus and mother. We investigated whether STBEVs from normal pregnant women might target liver cells in vitro and induce changes in lipid synthesis. This study was performed at the Nuffield Department of Women's & Reproductive Health, Oxford, UK. STBEVs were obtained by dual‐lobe placental perfusion from 11 normal pregnancies at term. Medium/large and small STBEVs were collected by ultracentrifugation at 10,000g and 150,000g, respectively. STBEVs were analysed by Western blot analysis and flow cytometry for co‐expression of apolipoprotein‐E (apoE) and placental alkaline phosphatase (PLAP). The uptake of STBEVs by liver cells and the effect on lipid metabolism was evaluated using a hepatocarcinoma cell line (HepG2 cells). Data were analysed by one‐way ANOVA and Student's t test. We demonstrated that: (a) STBEVs carry apoE; (b) HepG2 cells take up STBEVs through an apoE‐LDL receptor interaction; (c) STBEV incorporation into HepG2 cells resulted in (i) increased cholesterol release (ELISA); (ii) increased expression of the genes SQLE and FDPS (microarray) involved in cholesterol biosynthesis; (iii) downregulation of the CLOCK gene (microarray and PCR), involved in the circadian negative control of lipid synthesis in liver cells. In conclusion, the placenta may orchestrate the metabolic adaptation of the maternal liver through release of apoE‐positive STBEVs, by increasing lipid synthesis in a circadian‐independent fashion, meeting the nutritional needs of the growing foetus.

// Charlotte Taylor 1, 2 , David Mannion 1, 2 , Fabrizio Miranda 1, 2 , Mohammad Karaminejadranjbar 1, 2 , Sandra Herrero-Gonzalez 1, 2 , Karin Hellner 1, 2 , Yiyan Zheng 1, 2 , Geoffrey Bartholomeusz 3 , Robert C. Bast Jr 3 , Ahmed Ashour Ahmed 1, 2 1 Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford, OX3 9DS, UK 2 Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women’s Centre, John Radcliffe Hospital, Oxford, OX3 9DU, UK 3 Department of Experimental Therapeutics, M.D. Anderson Cancer Center, University of Texas, Houston, TX 77030, USA Correspondence to: Ahmed Ashour Ahmed, email: ahmed.ahmed@obs-gyn.ox.ac.uk Keywords: ovarian cancer, paclitaxel, mitotic arrest, PFKFB4, PFKFB3 Received: July 26, 2016 Accepted: December 15, 2016 Published: January 31, 2017 ABSTRACT Taxanes represent some of the most commonly used chemotherapeutic agents for ovarian cancer treatment. However, they are only effective in approximately 40% of patients. Novel therapeutic strategies are required to potentiate their effect and improve patient outcome. A hallmark of many cancers is the constitutive activation of the PI3K/AKT pathway, which drives cell survival and metabolism. We discovered a striking decrease in AKT activity coupled with a significant reduction in glucose 6-phosphate and ATP levels during mitotic arrest in the majority of ovarian cancer cell lines tested, indicating a potential metabolic vulnerability. A high-content siRNA screen to detect novel metabolic targets in mitotically arrested ovarian cancer cells identified the glycolytic enzyme PFKFB4. PFKFB4 depletion increased caspase 3/7 activity, and levels of reactive oxygen species only in mitotically arrested cells, and significantly enhanced mitotic cell death after paclitaxel treatment. Depletion of PFKFB3 demonstrated a similar phenotype. The observation that some ovarian cancer cells lose AKT activity during mitotic arrest and become vulnerable to metabolic targeting is a new concept in cancer therapy. Thus, combining mitotic-targeted therapies with glycolytic inhibitors may act to potentiate the effects of antimitotics in ovarian cancer through mitosis-specific cell death.

Though used widely in cancer therapy, paclitaxel only elicits a response in a fraction of patients. A strong determinant of paclitaxel tumor response is the state of microtubule dynamic instability. However, whether the manipulation of this physiological process can be controlled to enhance paclitaxel response has not been tested. Here, we show a previously unrecognized role of the microtubule-associated protein CRMP2 in inducing microtubule bundling through its carboxy terminus. This activity is significantly decreased when the FER tyrosine kinase phosphorylates CRMP2 at Y479 and Y499. The crystal structures of wild-type CRMP2 and CRMP2-Y479E reveal how mimicking phosphorylation prevents tetramerization of CRMP2. Depletion of FER or reducing its catalytic activity using sub-therapeutic doses of inhibitors increases paclitaxel-induced microtubule stability and cytotoxicity in ovarian cancer cells and in vivo. This work provides a rationale for inhibiting FER-mediated CRMP2 phosphorylation to enhance paclitaxel on-target activity for cancer therapy., Some anticancer drugs target cell microtubules inhibiting mitosis and cell division. Here, the authors show that CRMP2 induces microtubule bundling and that this activity is regulated by the FER kinase, thus providing a rationale for targeting FER in combination with microtubule-targeting drugs.

Fatty acid binding protein 4 (FABP4) is a fatty acid chaperone, which is induced during adipocyte differentiation. Previously we have shown that FABP4 in endothelial cells is induced by the NOTCH1 signalling pathway, the latter of which is involved in mechanisms of resistance to antiangiogenic tumour therapy. Here, we investigated the role of FABP4 in endothelial fatty acid metabolism and tumour angiogenesis. We analysed the effect of transient FABP4 knockdown in human umbilical vein endothelial cells on fatty acid metabolism, viability and angiogenesis. Through therapeutic delivery of siRNA targeting mouse FABP4, we investigated the effect of endothelial FABP4 knockdown on tumour growth and blood vessel formation. In vitro, siRNA-mediated FABP4 knockdown in endothelial cells led to a marked increase of endothelial fatty acid oxidation, an increase of reactive oxygen species and decreased angiogenesis. In vivo, we found that increased NOTCH1 signalling in tumour xenografts led to increased expression of endothelial FABP4 that decreased when NOTCH1 and VEGFA inhibitors were used in combination. Angiogenesis, growth and metastasis in ovarian tumour xenografts were markedly inhibited by therapeutic siRNA delivery targeting mouse endothelial FABP4. Therapeutic targeting of endothelial FABP4 by siRNA in vivo has antiangiogenic and antitumour effects with minimal toxicity and should be investigated further.

Open Access funded by Medical Research Council. Under a Creative Commons license.-- et al., Current screening methods for ovarian cancer can only detect advanced disease. Earlier detection has proved difficult because the molecular precursors involved in the natural history of the disease are unknown. To identify early driver mutations in ovarian cancer cells, we used dense whole genome sequencing of micrometastases and microscopic residual disease collected at three time points over three years from a single patient during treatment for high-grade serous ovarian cancer (HGSOC). The functional and clinical significance of the identified mutations was examined using a combination of population-based whole genome sequencing, targeted deep sequencing, multi-center analysis of protein expression, loss of function experiments in an in-vivo reporter assay and mammalian models, and gain of function experiments in primary cultured fallopian tube epithelial (FTE) cells. We identified frequent mutations involving a 40kb distal repressor region for the key stem cell differentiation gene SOX2. In the apparently normal FTE, the region was also mutated. This was associated with a profound increase in SOX2 expression (p, This work is funded by the Medical Research Council (H8RSRS00), Ovarian Cancer Action (HER00070), the Oxford Biomedical Research Centre, the National Institute for Health Research (HJRWAC05) and the Experimental Cancer Medicine Centre. MJG is recipient of a research contract from the Instituto de Salud Carlos III of the Ministerio Español de Sanidad y Consumo (Miguel Servet tipo II Program, CPII 13-00047). C.Y. acknowledges the support of an MRC New Investigator Research Grant (Ref No. MR-L001411-1) and the Wellcome Trust Core Award Grant Number 090532-Z-09-Z.

The TFAP2C transcription factor has been shown to downregulate transcription of the universal cell cycle inhibitor p21(cip) (CDKN1A). In examining the mechanism of TFAP2C-mediated repression, we have identified a ternary complex at the proximal promoter containing TFAP2C, the oncoprotein Myc, and the trimethylated lysine 4 of histone H3 (H3K4me3) demethylase, KDM5B. We demonstrated that while TFAP2C and Myc can downregulate the CDKN1A promoter independently, KDM5B acts as a corepressor dependent on the other two proteins. All three factors collaborate for optimal CDKN1A repression, which requires the AP-2 binding site at -111/-103 and KDM5B demethylase activity. Silencing of TFAP2C-KDM5B-Myc led to increased H3K4me3 at the endogenous promoter and full induction of CDKN1A expression. Coimmunoprecipitation assays showed that TFAP2C and Myc associate with distinct domains of KDM5B and the TFAP2C C-terminal 270 amino acids (aa) are required for Myc and KDM5B interaction. Overexpression of all three proteins resulted in forced S-phase entry and attenuation of checkpoint activation, even in the presence of chemotherapy drugs. Since each protein has been linked to poor prognosis in breast cancer, our findings suggest that the TFAP2C-Myc-KDM5B complex promotes cell cycle progression via direct CDKN1A repression, thereby contributing to tumorigenesis and therapy failure.

Although innumerable investigations regarding the biology of lung cancer have been carried out, many aspects thereof remain to be addressed, including the role played by the retinoblastoma-related protein Rb2/p130 during the evolution of this disease. Here we report novel findings on the mechanisms that control Rb2/p130 gene expression in lung fibroblasts and characterize the effects of Rb2/p130 deregulation on the proliferative features of lung cancer cells. We revealed for the first time that in lung fibroblasts the expression of Rb2/p130 gene is directly controlled by the chromatin insulator CCCTC-binding factor, CTCF, which by binding to the Rb2/p130 gene promoter induces, and/or maintains, a specific local chromatin organization that in turn governs the transcriptional activity of Rb2/p130 gene. However, in lung cancer cells the activity of CTCF in controlling Rb2/p130 gene expression is impaired by BORIS, a CTCF-paralogue, which by binding to the Rb2/p130 gene could trigger changes in the chromatin asset established by CTCF, thereby affecting CTCF regulatory activity on Rb2/p130 transcription. These studies not only provide essential basic insights into the molecular mechanisms that control Rb2/p130 gene expression in lung cancer, but also offer a potential paradigm for the actions of other activators and/or corepressors, such as CTCF and BORIS, that could be crucial in explaining how alterations in the mechanism regulating Rb2/p130 gene expression may accelerate the progression of lung tumors, or favor the onset of recurrence after cancer treatment. Mol Cancer Res; 9(2); 225–33. ©2011 AACR.

The adipocyte-rich microenvironment forms a niche for ovarian cancer metastasis, but the mechanisms driving this process are incompletely understood. Here we show that salt-inducible kinase 2 (SIK2) is overexpressed in adipocyte-rich metastatic deposits compared with ovarian primary lesions. Overexpression of SIK2 in ovarian cancer cells promotes abdominal metastasis while SIK2 depletion prevents metastasis in vivo. Importantly, adipocytes induce calcium-dependent activation and autophosphorylation of SIK2. Activated SIK2 plays a dual role in augmenting AMPK-induced phosphorylation of acetyl-CoA carboxylase and in activating the PI3K/AKT pathway through p85α-S154 phosphorylation. These findings identify SIK2 at the apex of the adipocyte-induced signaling cascades in cancer cells and make a compelling case for targeting SIK2 for therapy in ovarian cancer.

Background: High Grade Serous Ovarian Cancer (HGSOC) metastatic disease is strongly dependent on the adipocyte-rich microenvironment of the omentum. Altough previous work has shown that adipocytes are required for driving cancer metastasis to fat-rich environments, the mechanisms involved in the process of linking metabolism to cancer cell survival at this niche have remained poorly understood and this has, therefore, hindered therapeutic exploitation. We have previously shown that the expression of the Salt Inducible Kinase 2 (SIK2) is important for ovarian cancer cell survival and that it correlates with poor patient survival (Ahmed et al., Cancer Cell, 2010). In this work we present a previously unrecognised role for SIK2 in driving cancer cell metabolism and proliferation at the omental metastatic niche. Methods: We established a system for the co-culture of cancer cells with adipocytes obtained from freshly excised normal omentum from women undergoing surgical staging. This system was used in combination with a chemical biology approach utilizing cells expressing gate-keeper mutants of SIK2 and a type I kinase inhibitor to test the specificity of observed phenotypic effects. Our results were validated using immunohistochemistry of a panel of ovarian cancers and a xenograft model of ovarian cancer metastasis. Results: SIK2 was significantly overexpressed in omental metastases of ovarian tumours compared to paired ovarian cancer primary lesions from the same patients. In a xenograft model of ovarian cancer metastasis SIK2-overexpressing cells implanted orthotopically at the ovarian bursa formed significantly larger omental metastases compared to cells with endogenous levels of SIK2. We first observed that co-culture of ovarian cancer cells with adipocytes resulted in an increased SIK2 autophosphorylation and activation which, in turn stimulated cancer cell proliferation. Next, we showed that PLC-dependent activation of calcium release was required for adipocyte-induced SIK2 autophosphorylation in ovarian cancer cells. Surprisingly, we identified a role for adipocyte-activated SIK2 in stimulating cancer cell metabolism throught augmenting AMPK-induced phosphorylation of ACC and activation of carnitine palmitoyltransferase 1 (CPT1) transcription. Concurrently, SIK2 was required to activate the PI3K complex through direct p85α-S154 phosphorylation. This was confirmed using rapamycin as a known robust paradoxical PI3K activator showing that SIK2 siRNA-mediated depletion or its chemical inhibition abolished rapamycin-induced AKT phosphorylation and sensitized ovarian cancer cells to its cytotoxic effect. Conclusion: Our results suggested that SIK2 phosphorylation and activation were required to establish ovarian cancer lesions at the adipocyte-rich omental environment. Therefore we suggest a therapeutic role for targeting SIK2 in preventing ovarian cancer metastases. Citation Format: Fabrizio Miranda, Shujuan Liu, Sandra Herrero-Gonzalez, David Mannion, Stefan Knapp, Ahmed A. Ahmed. The salt inducible kinase 2 (SIK2) links lipid metabolism to survival of ovarian cancer metastasis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4111. doi:10.1158/1538-7445.AM2015-4111