HOXB13 controls cell state through super-enhancers.

Expression of the homeodomain transcription factor HOXB13 has been demonstrated in several malignancies but its role in tumorigenesis remains elusive. We observed high levels of HOXB13 in poorly differentiated pediatric tumors including a highly aggressive childhood neoplasm - malignant rhabdoid tumor. In a xenograft model of rhabdoid tumor, knockout of HOXB13 diminished tumor growth while partial knockdown of HOXB13 promoted differentiation of tumor cells into bone. These results suggest that HOXB13 enhances rhabdoid malignancy by interfering with mesenchymal stem cell differentiation. Consistent with this hypothesis, overexpression of HOXB13 in mesenchymal progenitor cells inhibited adipogenic, myogenic, and osteogenic differentiation. Mechanistically, we demonstrated that HOXB13 binds to super-enhancer regions regulating genes involved in differentiation and tumorigenesis.

Prevention and management of statin adverse effects: A practical approach for pharmacists.

Statin-associated adverse effects, primarily muscle-related symptoms, occur in up to approximately one-third of patients in clinical practice. Recently, a Canadian Consensus Working Group outlined 6 key principles to assess and manage patients with goal-inhibiting statin intolerance, defined as a syndrome characterized by symptoms or biomarker abnormalities that prevent the long-term use of and adherence to indicated statin therapy, which includes a trial of at least 2 statins and precludes reversible causes of statin adverse effects. These principles ensure patients are appropriately receiving a statin and aware of both the benefits and risks of therapy. As well, they address factors that may increase the risk of statin-associated myopathy. A thorough assessment of patients' clinical and laboratory history should be performed in any patient presenting with muscle symptoms on statin therapy, followed by a systematic dechallenge/rechallenge approach. In practice, most patients with statin intolerance due to muscle symptoms will be able to tolerate another statin. This is of particular importance because of the relative paucity of compelling evidence demonstrating a cardiovascular benefit with nonstatin therapies. Pharmacists are ideally situated to provide patient education, recommend changes to therapy and monitor patients with goal-inhibiting statin intolerance.

ADAM12 is a prognostic factor associated with an aggressive molecular subtype of high-grade serous ovarian carcinoma.

ADAM metallopeptidase domain 12 (ADAM12) is a promising biomarker because of its low expression in normal tissues and high expression in a variety of human cancers. However, ADAM12 levels in ovarian cancer have not been well characterized. We previously identified ADAM12 as one of the signature genes associated with poor survival in high-grade serous ovarian carcinoma (HGSOC). Here, we sought to determine if high levels of the ADAM12 protein and/or messenger RNA (mRNA) are associated with clinical variables in HGSOC. We show that high protein levels of ADAM12 in banked preoperative sera are associated with shorter progression-free and overall survival. Tumor levels of ADAM12 mRNA were also associated with shorter progression-free and overall survival as well as with lymphatic and vascular invasion, and residual tumor volume following cytoreductive surgery. The majority of genes co-expressed with ADAM12 in HGSOC were transforming growth factor (TGF)ß signaling targets that function in collagen remodeling and cell-matrix adhesion. In tumor sections, the ADAM12 protein and mRNA were expressed in epithelial cancer cells and surrounding stromal cells. In vitro data showed that ADAM12 mRNA levels can be increased by TGFß signaling and direct contact between epithelial and stromal cells. High tumor levels of ADAM12 mRNA were characteristic of the mesenchymal/desmoplastic molecular subtype of HGSOC, which is known to have the poorest prognosis. Thus, ADAM12 may be a useful biomarker of aggressive ovarian cancer for which standard treatment is not effective.

Suboptimal cytoreduction in ovarian carcinoma is associated with molecular pathways characteristic of increased stromal activation.

OBJECTIVE: Suboptimal cytoreductive surgery in advanced epithelial ovarian cancer (EOC) is associated with poor survival but it is unknown if poor outcome is due to the intrinsic biology of unresectable tumors or insufficient surgical effort resulting in residual tumor-sustaining clones. Our objective was to identify the potential molecular pathway(s) and cell type(s) that may be responsible for suboptimal surgical resection. METHODS: By comparing gene expression in optimally and suboptimally cytoreduced patients, we identified a gene network associated with suboptimal cytoreduction and explored the biological processes and cell types associated with this gene network. RESULTS: We show that primary tumors from suboptimally cytoreduced patients express molecular signatures that are typically present in a distinct molecular subtype of EOC characterized by increased stromal activation and lymphovascular invasion. Similar molecular pathways are present in EOC metastases, suggesting that primary tumors in suboptimally cytoreduced patients are biologically similar to metastatic tumors. We demonstrate that the suboptimal cytoreduction network genes are enriched in reactive tumor stroma cells rather than malignant tumor cells. CONCLUSION: Our data suggest that the success of cytoreductive surgery is dictated by tumor biology, such as extensive stromal reaction and increased invasiveness, which may hinder surgical resection and ultimately lead to poor survival.

Correlation of glucocorticoid-mediated E4BP4 upregulation with altered expression of pro- and anti-apoptotic genes in CEM human lymphoblastic leukemia cells.

In Caenorhabditiselegans, motorneuron apoptosis is regulated via a ces-2-ces-1-egl-1 pathway. We tested whether human CEM lymphoblastic leukemia cells undergo apoptosis via an analogous pathway. We have previously shown that E4BP4, a ces-2 ortholog, mediates glucocorticoid (GC)-dependent upregulation of BIM, an egl-1 ortholog, in GC-sensitive CEM C7-14 cells and in CEM C1-15mE#3 cells, which are sensitized to GCs by ectopic expression of E4BP4. In the present study, we demonstrate that the human ces-1 orthologs, SLUG and SNAIL, are not significantly repressed in correlation with E4BP4 expression. Expression of E4BP4 homologs, the PAR family genes, especially HLF, encoding a known anti-apoptotic factor, was inverse to that of E4BP4 and BIM. Expression of pro- and anti-apoptotic genes in CEM cells was analyzed via an apoptosis PCR Array. We identified BIRC3 and BIM as genes whose expression paralleled that of E4BP4, while FASLG, TRAF4, BCL2A1, BCL2L1, BCL2L2 and CD40LG as genes whose expression was opposite to that of E4BP4.

Phenotypic Consequences of SLC25A40-ABCB1 Fusions beyond Drug Resistance in High-Grade Serous Ovarian Cancer.

Despite high response rates to initial chemotherapy, the majority of women diagnosed with High-Grade Serous Ovarian Cancer (HGSOC) ultimately develop drug resistance within 1-2 years of treatment. We previously identified the most common mechanism of acquired resistance in HGSOC to date, transcriptional fusions involving the ATP-binding cassette (ABC) transporter ABCB1, which has well established roles in multidrug resistance. However, the underlying biology of fusion-positive cells, as well as how clonal interactions between fusion-negative and positive populations influences proliferative fitness and therapeutic response remains unknown. Using a panel of fusion-negative and positive HGSOC single-cell clones, we demonstrate that in addition to mediating drug resistance, ABCB1 fusion-positive cells display impaired proliferative capacity, elevated oxidative metabolism, altered actin cellular morphology and an extracellular matrix/inflammatory enriched transcriptional profile. The co-culture of fusion-negative and positive populations had no effect on cellular proliferation but markedly altered drug sensitivity to doxorubicin, paclitaxel and cisplatin. Finally, high-throughput screening of 2907 FDA-approved compounds revealed 36 agents that induce equal cytotoxicity in both pure and mixed ABCB1 fusion populations. Collectively, our findings have unraveled the underlying biology of ABCB1 fusion-positive cells beyond drug resistance and identified novel therapeutic agents that may significantly improve the prognosis of relapsed HGSOC patients.

Clinical MDR1 inhibitors enhance Smac-mimetic bioavailability to kill murine LSCs and improve survival in AML models.

The specific targeting of inhibitor of apoptosis (IAP) proteins by Smac-mimetic (SM) drugs, such as birinapant, has been tested in clinical trials of acute myeloid leukemia (AML) and certain solid cancers. Despite their promising safety profile, SMs have had variable and limited success. Using a library of more than 5700 bioactive compounds, we screened for approaches that could sensitize AML cells to birinapant and identified multidrug resistance protein 1 inhibitors (MDR1i) as a class of clinically approved drugs that can enhance the efficacy of SM therapy. Genetic or pharmacological inhibition of MDR1 increased intracellular levels of birinapant and sensitized AML cells from leukemia murine models, human leukemia cell lines, and primary AML samples to killing by birinapant. The combination of clinical MDR1 and IAP inhibitors was well tolerated in vivo and more effective against leukemic cells, compared with normal hematopoietic progenitors. Importantly, birinapant combined with third-generation MDR1i effectively killed murine leukemic stem cells (LSCs) and prolonged survival of AML-burdened mice, suggesting a therapeutic opportunity for AML. This study identified a drug combination strategy that, by efficiently killing LSCs, may have the potential to improve outcomes in patients with AML.

Multiple ABCB1 transcriptional fusions in drug resistant high-grade serous ovarian and breast cancer.

ABCB1 encodes Multidrug Resistance protein (MDR1), an ATP-binding cassette member involved in the cellular efflux of chemotherapeutic drugs. Here we report that ovarian and breast samples from chemotherapy treated patients are positive for multiple transcriptional fusions involving ABCB1, placing it under the control of a strong promoter while leaving its open reading frame intact. We identified 15 different transcriptional fusion partners involving ABCB1, as well as patients with multiple distinct fusion events. The partner gene selected depended on its structure, promoter strength, and chromosomal proximity to ABCB1. Fusion positivity was strongly associated with the number of lines of MDR1-substrate chemotherapy given. MDR1 inhibition in a fusion positive ovarian cancer cell line increased sensitivity to paclitaxel more than 50-fold. Convergent evolution of ABCB1 fusion is therefore frequent in chemotherapy resistant recurrent ovarian cancer. As most currently approved PARP inhibitors (PARPi) are MDR1 substrates, prior chemotherapy may precondition resistance to PARPi.

Going to extremes: determinants of extraordinary response and survival in patients with cancer.

Research into factors affecting treatment response or survival in patients with cancer frequently involves cohorts that span the most common range of clinical outcomes, as such patients are most readily available for study. However, attention has turned to highly unusual patients who have exceptionally favourable or atypically poor responses to treatment and/or overall survival, with the expectation that patients at the extremes may provide insights that could ultimately improve the outcome of individuals with more typical disease trajectories. While clinicians can often recount surprising patients whose clinical journey was very unusual, given known clinical characteristics and prognostic indicators, there is a lack of consensus among researchers on how best to define exceptional patients, and little has been proposed for the optimal design of studies to identify factors that dictate unusual outcome. In this Opinion article, we review different approaches to identifying exceptional patients with cancer and possible study designs to investigate extraordinary clinical outcomes. We discuss pitfalls with finding these rare patients, including challenges associated with accrual of patients across different treatment centres and time periods. We describe recent molecular and immunological factors that have been identified as contributing to unusual patient outcome and make recommendations for future studies on these intriguing patients.

Mechanisms of Drug Resistance in High-Grade Serous Ovarian Cancer.

Resistance in ovarian cancer is driven by a range of mechanisms, some of which are therapy specific whereas others confer multidrug resistance. This review outlines our current understanding of the heterogeneous mechanisms of both primary and acquired drug resistance in high-grade serous ovarian cancer with a focus on the most common therapeutics, including platinum and taxanes. Current therapeutic strategies for overcoming resistance, including the use of non-P- glycoprotein substrate therapies, are outlined, with an emphasis on the importance of developing resistance biomarkers to guide future therapy approaches and improve patient outcomes.

Penetration of Vancomycin into the Cerebrospinal Fluid: A Systematic Review.

INTRODUCTION: Infectious disease and pharmacokinetic textbooks indicate that vancomycin has poor penetration into the central nervous system due to its hydrophilic nature and high molecular weight. Recent literature suggests that penetration of vancomycin into cerebrospinal fluid (CSF) is higher than previously reported; therefore, we conducted a systematic review to assess the penetration of vancomycin into CSF. METHODS: We searched the MEDLINE, EMBASE, and CENTRAL electronic databases for English-language human studies evaluating serum and CSF concentrations of intravenous vancomycin. RESULTS: In 13 identified studies, the CSF-to-serum ratio of vancomycin varied from 0.00 to 0.81. CSF penetration ranged 0.06-0.81 in patients with meningitis, 0.05-0.17 in ventriculitis, 0.00-0.36 in other infections, and 0-0.13 in patients without infection. Despite variable CSF penetration, 83% of patients with meningitis and 100% of patients with ventriculitis achieved clinical cure. No factor predicted vancomycin CSF penetration. CONCLUSION: Contrary to prior belief, studies included in our review did not show universally low penetration of vancomycin into CSF. CSF vancomycin levels were variable and did not predict clinical cure.

Roles of Infectious Diseases Consultant Pharmacists and Antimicrobial Stewardship Pharmacists: A Survey of Canadian Tertiary Care Academic Hospitals.

BACKGROUND: Infectious diseases consultant (IDC) pharmacists work within an IDC service to care for inpatients with complex infections. With Accreditation Canada's new Required Organizational Practice promoting the establishment of antimicrobial stewardship (AMS) programs, AMS pharmacists are being employed in acute care hospitals. There is potential for overlap in responsibilities between IDC and AMS pharmacists, but there is no literature outlining the current duties for each group in Canada. OBJECTIVE: To describe the demographic characteristics and roles of IDC and AMS pharmacists in Canadian tertiary care academic hospitals. METHODS: A survey of IDC and AMS pharmacists at Canadian tertiary care academic hospitals was conducted between February and April 2015. The questionnaire included questions about the pharmacist's experience, education, and training; the institution where the pharmacist was practising; the IDC or AMS team characteristics; and the pharmacist's roles in clinical, educational, administrative, and research sectors. RESULTS: The survey response rate was 77% (68/88). The 68 respondents self-identified as IDC pharmacists (14 [21%]), AMS pharmacists (34 [50%]), or dual-role IDC and AMS pharmacists (20 [29%]). Compared with AMS pharmacists, IDC pharmacists reported more of the following unique clinical activities: directly communicating with patients, attending rounds, involving patients in decision-making, and providing patient education. The 3 groups of pharmacists described similar educational responsibilities. The AMS pharmacists performed more of the following administrative and research duties: development of antibiograms and preprinted orders, collection of antimicrobial metrics, and drug-use evaluations for antimicrobials. Dual-role IDC and AMS pharmacists were involved in fewer of the unique activities described by those who practised within a single subspecialty. CONCLUSIONS: Self-identified IDC and AMS pharmacists in Canadian tertiary care academic hospitals were performing many similar roles; however, distinct differences within the clinical, administrative, and research domains were identified among IDC pharmacists, AMS pharmacists, and those who identified as dual-role IDC and AMS pharmacists.

CONTEXTE: Les pharmaciens consultants en maladies infectieuses travaillent au sein d'un service de consultants en maladies infectieuses afin de prodiguer des soins aux patients hospitalisés atteints d'infections complexes. Or, en raison de la nouvelle Pratique organisationnelle requise d'Agrément Canada qui encourage la mise en œuvre de programmes de gérance des antimicrobiens, des pharmaciens sont affectés à cette fonction dans les hôpitaux de soins de courte durée. On distingue un possible chevauchement des responsabilités entre les pharmaciens consultants en maladies infectieuses et ceux chargés de la gérance des antimicrobiens, mais il n'y a aucun document qui définit les responsabilités actuelles pour chacun de ces groupes au Canada. OBJECTIF: Décrire les caractéristiques démographiques et les rôles des pharmaciens consultants en maladies infectieuses et de ceux chargés de la gérance des antimicrobiens dans les hôpitaux universitaires de soins tertiaires au Canada. MÉTHODES: Entre février et avril 2015, on a mené un sondage auprès des pharmaciens consultants en maladies infectieuses et de ceux chargés de la gérance des antimicrobiens travaillant dans les hôpitaux universitaires de soins tertiaires au Canada. Les questions portaient, entre autres, sur l'expérience du pharmacien, ses études et sa formation, l'établissement où il travaillait, les caractéristiques des équipes de consultants en maladies infectieuses et de gérance des antimicrobiens ainsi que sur ses rôles dans les secteurs cliniques et administratifs et dans les secteurs de la formation et de la recherche. RÉSULTATS: Le taux de réponse au sondage était de 77 % (68/88). Les 68 répondants s'identifiaient comme des pharmaciens consultants en maladies infectieuses (14 [21 %]), des pharmaciens chargés de la gérance des antimicrobiens (34 [50 %]) ou des pharmaciens occupant les deux rôles (20 [29 %]). Comparativement à leur collègues chargés de la gérance des antimicrobiens, les pharmaciens consultants en maladies infectieuses ont davantage indiqué accomplir les activités cliniques uniques suivantes : communiquer directement avec les patients, participer aux tournées médicales, amener les patients à participer aux prises de décisions et offrir des conseils aux patients. Les trois groupes de pharmaciens ont évoqué des responsabilités éducatives similaires. Les pharmaciens chargés de la gérance des antimicrobiens accomplissaient davantage les tâches administratives et de recherche suivantes : élaboration d'antibiogrammes et d'ordonnances préimprimées, cueillette de mesures sur les antimicrobiens et évaluation de l'utilisation des antimicrobiens. Les pharmaciens qui cumulaient les deux rôles participaient à un moins grand nombre des activités uniques décrites par ceux qui exerçaient une seule sous-spécialité. CONCLUSIONS: Les pharmaciens des hôpitaux universitaires de soins tertiaires au Canada qui s'identifiaient eux-mêmes comme des pharmaciens consultants en maladies infectieuses ou des pharmaciens chargés de la gérance des antimicrobiens exécutaient bon nombre de tâches similaires. Cependant, des différences marquées en ce qui touche aux domaines clinique et administratif et à celui de la recherche ont été repérées entre les pharmaciens consultants en maladies infectieuses, ceux chargés de la gérance des antimicrobiens et ceux occupant les deux rôles.

Sphingosine kinase 1 is required for TGF-ß mediated fibroblastto- myofibroblast differentiation in ovarian cancer.

Sphingosine kinase 1 (SPHK1), the enzyme that produces sphingosine 1 phosphate (S1P), is known to be highly expressed in many cancers. However, the role of SPHK1 in cells of the tumor stroma remains unclear. Here, we show that SPHK1 is highly expressed in the tumor stroma of high-grade serous ovarian cancer (HGSC), and is required for the differentiation and tumor promoting function of cancer-associated fibroblasts (CAFs). Knockout or pharmacological inhibition of SPHK1 in ovarian fibroblasts attenuated TGF-ß-induced expression of CAF markers, and reduced their ability to promote ovarian cancer cell migration and invasion in a coculture system. Mechanistically, we determined that SPHK1 mediates TGF-ß signaling via the transactivation of S1P receptors (S1PR2 and S1PR3), leading to p38 MAPK phosphorylation. The importance of stromal SPHK1 in tumorigenesis was confirmed in vivo, by demonstrating a significant reduction of tumor growth and metastasis in SPHK1 knockout mice. Collectively, these findings demonstrate the potential of SPHK1 inhibition as a novel stroma-targeted therapy in HGSC.

Redox regulation of p38 MAPK activation and expression of ICAM-1 and heme oxygenase-1 in human alveolar epithelial (A549) cells.

We have explored the potential role of redox events in p38 mitogen-activated protein kinase (MAPK) activation and their relevance to the inducible expression of intercellular adhesion molecule-1 (ICAM-1) and heme oxygenase-1 (HO-1) in A549 cells. Tumor necrosis factor-alpha (TNFalpha) and hydrogen peroxide (H2O2) both activated p38, but only TNFalpha activated nuclear factor-kappaB (NF-kappaB). N-Acetyl-L-cysteine (20 mM) inhibited both H2O2- and TNFalpha-induced p38 phosphorylation (14 +/- 7 and 37 +/- 4% of control, respectively). The mitochondrial complex I and III inhibitors, rotenone and antimycin A, and allopurinol partially inhibited H2O2- but not TNFalpha-induced p38 activation. However, rotenone and antimycin A augmented intracellular oxidative stress measured by dichlorofluorescein fluorescence. TNFalpha, but not H2O2, induced ICAM-1 in A549 cells, which was attenuated by a proteasome inhibitor, but not by the p38 MAPK inhibitor SB203580. In contrast, hemin and hemoglobin, but neither TNFalpha nor H2O2, caused efficient HO-1 expression. However, hemin had no effect on p38 activation and SB203580 did not influence hemin-induced HO-1 protein expression. Collectively, these data suggest that p38 is a cytokine- and oxidative stress-responsive pathway in A549 cells. Whereas NF-kappaB appears crucial in ICAM-1 induction, p38 activation itself is not sufficient to confer HO-1 expression and may not be involved in HO-1 and ICAM-1 induction in A549 cells.

Differential expression of argininosuccinate synthetase in serous and non-serous ovarian carcinomas.

The current standard of care for epithelial ovarian cancer does not discriminate between different histologic subtypes (serous, clear cell, endometrioid and mucinous) despite the knowledge that ovarian carcinoma subtypes do not respond uniformly to conventional platinum/taxane-based chemotherapy. Exploiting addictions and vulnerabilities in cancers with distinguishable molecular features presents an opportunity to develop individualized therapies that may be more effective than the current 'one size fits all' approach. One such opportunity is arginine depletion therapy with pegylated arginine deiminase, which has shown promise in several cancer types that exhibit low levels of argininosuccinate synthetase including hepatocellular and prostate carcinoma and melanoma. Based on the high levels of argininosuccinate synthetase previously observed in ovarian cancers, these tumours have been considered unlikely candidates for arginine depletion therapy. However, argininosuccinate synthetase levels have not been evaluated in the individual histologic subtypes of ovarian carcinoma. The current study is the first to examine the expression of argininosuccinate synthetase at the mRNA and protein levels in large cohorts of primary and recurrent ovarian carcinomas and ovarian cancer cell lines. We show that the normal fallopian tube fimbria and the majority of primary high-grade and low-grade serous ovarian carcinomas express high levels of argininosuccinate synthetase, which tend to further increase in recurrent tumours. In contrast to the serous subtype, non-serous ovarian carcinoma subtypes (clear cell, endometrioid and mucinous) frequently lack detectable argininosuccinate synthetase expression. The in vitro sensitivity of ovarian cancer cell lines to arginine depletion with pegylated arginine deiminase was inversely correlated with argininosuccinate synthetase expression. Our data suggest that the majority of serous ovarian carcinomas are not susceptible to therapeutic intervention with arginine deiminase while a subset of non-serous ovarian carcinoma subtypes are auxotrophic for arginine and should be considered for clinical trials with pegylated arginine deiminase.

Reversing Platinum Resistance in High-Grade Serous Ovarian Carcinoma: Targeting BRCA and the Homologous Recombination System.

Resistance to platinum chemotherapy is one of the main factors driving ovarian cancer mortality, and overcoming platinum resistance is considered one of the greatest challenges in ovarian cancer research. Genetic and functional evidence points to the homologous recombination (HR) DNA repair system, and BRCA1 and BRCA2 in particular, as main determinants of response to platinum therapy. BRCA-mutant ovarian cancers are especially sensitive to platinum, associated with better survival, and amenable to poly ADP ribose polymerase inhibitor treatment. Here, we discuss a therapeutic concept that seeks to disrupt HR capacity via targeting of BRCA1 and BRCA2 functionality in order to reverse platinum resistance in BRCA-proficient high-grade serous ovarian cancers (HGSOC). We review the molecular signaling pathways that converge on BRCA1 and BRCA2, their activation status in ovarian cancer, and therapeutic options to modulate BRCA function. Several recent publications demonstrate efficient chemosensitization of BRCA-proficient cancers by combining targeted therapy with standard platinum-based agents. Due to its inherent genomic heterogeneity, molecularly defined subgroups of HGSOC may require different approaches. We seek to provide an overview of available agents and their potential use to reverse platinum resistance by inhibiting the HR system, either directly or indirectly, by targeting oncogenic activators of HR.

A collagen-remodeling gene signature regulated by TGF-ß signaling is associated with metastasis and poor survival in serous ovarian cancer.

PURPOSE: To elucidate molecular pathways contributing to metastatic cancer progression and poor clinical outcome in serous ovarian cancer. EXPERIMENTAL DESIGN: Poor survival signatures from three different serous ovarian cancer datasets were compared and a common set of genes was identified. The predictive value of this gene signature was validated in independent datasets. The expression of the signature genes was evaluated in primary, metastatic, and/or recurrent cancers using quantitative PCR and in situ hybridization. Alterations in gene expression by TGF-ß1 and functional consequences of loss of COL11A1 were evaluated using pharmacologic and knockdown approaches, respectively. RESULTS: We identified and validated a 10-gene signature (AEBP1, COL11A1, COL5A1, COL6A2, LOX, POSTN, SNAI2, THBS2, TIMP3, and VCAN) that is associated with poor overall survival (OS) in patients with high-grade serous ovarian cancer. The signature genes encode extracellular matrix proteins involved in collagen remodeling. Expression of the signature genes is regulated by TGF-ß1 signaling and is enriched in metastases in comparison with primary ovarian tumors. We demonstrate that levels of COL11A1, one of the signature genes, continuously increase during ovarian cancer disease progression, with the highest expression in recurrent metastases. Knockdown of COL11A1 decreases in vitro cell migration, invasion, and tumor progression in mice. CONCLUSION: Our findings suggest that collagen-remodeling genes regulated by TGF-ß1 signaling promote metastasis and contribute to poor OS in patients with serous ovarian cancer. Our 10-gene signature has both predictive value and biologic relevance and thus may be useful as a therapeutic target.

Succinate dehydrogenase inhibition leads to epithelial-mesenchymal transition and reprogrammed carbon metabolism.

BACKGROUND: Succinate dehydrogenase (SDH) is a mitochondrial metabolic enzyme complex involved in both the electron transport chain and the citric acid cycle. SDH mutations resulting in enzymatic dysfunction have been found to be a predisposing factor in various hereditary cancers. Therefore, SDH has been implicated as a tumor suppressor. RESULTS: We identified that dysregulation of SDH components also occurs in serous ovarian cancer, particularly the SDH subunit SDHB. Targeted knockdown of Sdhb in mouse ovarian cancer cells resulted in enhanced proliferation and an epithelial-to-mesenchymal transition (EMT). Bioinformatics analysis revealed that decreased SDHB expression leads to a transcriptional upregulation of genes involved in metabolic networks affecting histone methylation. We confirmed that Sdhb knockdown leads to a hypermethylated epigenome that is sufficient to promote EMT. Metabolically, the loss of Sdhb resulted in reprogrammed carbon source utilization and mitochondrial dysfunction. This altered metabolic state of Sdhb knockdown cells rendered them hypersensitive to energy stress. CONCLUSIONS: These data illustrate how SDH dysfunction alters the epigenetic and metabolic landscape in ovarian cancer. By analyzing the involvement of this enzyme in transcriptional and metabolic networks, we find a metabolic Achilles' heel that can be exploited therapeutically. Analyses of this type provide an understanding how specific perturbations in cancer metabolism may lead to novel anticancer strategies.

E4BP4 facilitates glucocorticoid-evoked apoptosis of human leukemic CEM cells via upregulation of Bim.

BACKGROUND: Synthetic GCs serve as therapeutic agents for some lymphoid leukemias because of their ability to induce transcriptional changes via the GC receptor (GR) and trigger apoptosis. Upregulation of the BH3-only member of Bcl-2 family proteins, Bim, has been shown to be essential for GC-evoked apoptosis of leukemic lymphoblasts. Using human T cell leukemic sister clones CEM-C7-14 and CEM-C1-15, we have previously shown that the bZIP transcriptional repressor, E4BP4, is preferentially upregulated by GCs in CEM-C7-14 cells that are susceptible to GC-evoked apoptosis, but not in refractory CEM-C1-15 cells. E4BP4 is an evolutionarily conserved member of the PAR family of bZIP transcription factors related to the C. elegans death specification gene ces2. RESULTS: Mouse E4BP4 was ectopically expressed in CEM-C1-15 cells, resulting in sensitization to GC-evoked apoptosis in correlation with restoration of E4BP4 and Bim upregulation. shRNA mediated modest knockdown of E4BP4 in CEM-C7-14 cells resulted in concomitant reduction in Bim expression, although GC-evoked fold-induction and sensitivity to apoptosis was similar to parental cells. CONCLUSION: Data presented here suggest that GC-mediated upregulation of E4BP4 facilitates Bim upregulation and apoptosis of CEM cells. Since the Bim promoter does not contain any consensus GRE or EBPRE sequences, induction of Bim may be a secondary response.