Integrating MDT Tumor Board Shadowing into the Undergraduate Medical Curriculum: Perspective of Medical Students

Site-specific multidisciplinary team (MDT) tumor boards are valuable resources for medical students, enabling them to familiarize themselves with the latest evidence-based cancer management strategies and observe effective teamwork in action. In this study, we looked at the awareness and perceptions of medical students about incorporating MDT tumor boards in the medical curriculum. A cross-sectional study was conducted among medical students from year 1 to year 5 at the Aga Khan University after exemption from ethical review committee. A 20-item self-administered questionnaire was used to evaluate the awareness and perceptions of medical students regarding MDT tumor boards. A total of 285 medical students participated in this study, with their mean age (± standard deviation) being 21.91 ± 1.67 years. A majority of 183 (64.2%) had no prior knowledge of the existence of a site-specific MDT tumor board for cancer management. Of the 285 students, 252 (88.4%) demonstrated sufficient awareness of the effectiveness of MDT tumor boards; similarly, 232 (81.4%) responded positively to the idea of mandatory tumor board rotations being incorporated into the undergraduate curriculum. No significant association was found between the student's year of study (χ2 = 6.03, p = 0.20) or gender (χ2 = 35, p = 0.84) and their perceptions of the effectiveness of MDT tumor boards. However, it was found that students who had prior knowledge of their existence had a stronger association with sufficient awareness (χ2 = 4.2, p = 0.04). The results indicate that while the majority of the medical students have no prior attendance or knowledge regarding MDT tumor boards, there is an overwhelming willingness among students to incorporate them into the medical curriculum.

Specialist multidisciplinary input maximises rare disease diagnoses from whole genome sequencing

Diagnostic whole genome sequencing (WGS) is increasingly used in rare diseases. However, standard, semi-automated WGS analysis may overlook diagnoses in complex disorders. Here, we show that specialist multidisciplinary analysis of WGS, following an initial 'no primary findings' (NPF) report, improves diagnostic rates and alters management. We undertook WGS in 102 adults with diagnostically challenging primary mitochondrial disease phenotypes. NPF cases were reviewed by a genomic medicine team, thus enabling bespoke informatic approaches, co-ordinated phenotypic validation, and functional work. We enhanced the diagnostic rate from 16.7% to 31.4%, with management implications for all new diagnoses, and detected strong candidate disease-causing variants in a further 3.9% of patients. This approach presents a standardised model of care that supports mainstream clinicians and enhances diagnostic equity for complex disorders, thereby facilitating access to the potential benefits of genomic healthcare. This research was made possible through access to the data and findings generated by the 100,000 Genomes Project: http://www.genomicsengland.co.uk .

Genome sequencing reveals underdiagnosis of primary ciliary dyskinesia in bronchiectasis

BACKGROUND

Bronchiectasis can result from infectious, genetic, immunological and allergic causes. 60-80% of cases are idiopathic, but a well-recognised genetic cause is the motile ciliopathy, primary ciliary dyskinesia (PCD). Diagnosis of PCD has management implications including addressing comorbidities, implementing genetic and fertility counselling and future access to PCD-specific treatments. Diagnostic testing can be complex; however, PCD genetic testing is moving rapidly from research into clinical diagnostics and would confirm the cause of bronchiectasis.

METHODS

This observational study used genetic data from severe bronchiectasis patients recruited to the UK 100,000 Genomes Project and patients referred for gene panel testing within a tertiary respiratory hospital. Patients referred for genetic testing due to clinical suspicion of PCD were excluded from both analyses. Data were accessed from the British Thoracic Society audit, to investigate whether motile ciliopathies are underdiagnosed in people with bronchiectasis in the UK.

RESULTS

Pathogenic or likely pathogenic variants were identified in motile ciliopathy genes in 17 (12%) out of 142 individuals by whole-genome sequencing. Similarly, in a single centre with access to pathological diagnostic facilities, 5-10% of patients received a PCD diagnosis by gene panel, often linked to normal/inconclusive nasal nitric oxide and cilia functional test results. In 4898 audited patients with bronchiectasis, <2% were tested for PCD and <1% received genetic testing.

CONCLUSIONS

PCD is underdiagnosed as a cause of bronchiectasis. Increased uptake of genetic testing may help to identify bronchiectasis due to motile ciliopathies and ensure appropriate management.

Compression moulding and injection over moulding of porous PEEK components

A simple and adaptable process for the production of porous PEEK has been demonstrated herein, which uses compression moulding to infiltrate molten PEEK into of a packed bed of salt beads. The process has the capacity to vary the pore size and porosity within the range suitable for materials to replace bone, but compressive testing showed the stiffness to be well below the target to match trabecular bone. This issue was addressed by creating a hybrid structure, integrating "pillars" of solid PEEK into the porous structure, by the injection over-moulding of compression moulded PEEK-salt inserts that contained drilled holes. Good bonding between the moulding and the insert was demonstrated and it was found that as little as 35 mm² of support, in the form of PEEK "pillars" was required to achieve the target performance.

De Novo SOX6 Variants Cause a Neurodevelopmental Syndrome Associated with ADHD, Craniosynostosis, and Osteochondromas

SOX6 belongs to a family of 20 SRY-related HMG-box-containing (SOX) genes that encode transcription factors controlling cell fate and differentiation in many developmental and adult processes. For SOX6, these processes include, but are not limited to, neurogenesis and skeletogenesis. Variants in half of the SOX genes have been shown to cause severe developmental and adult syndromes, referred to as SOXopathies. We here provide evidence that SOX6 variants also cause a SOXopathy. Using clinical and genetic data, we identify 19 individuals harboring various types of SOX6 alterations and exhibiting developmental delay and/or intellectual disability; the individuals are from 17 unrelated families. Additional, inconstant features include attention-deficit/hyperactivity disorder (ADHD), autism, mild facial dysmorphism, craniosynostosis, and multiple osteochondromas. All variants are heterozygous. Fourteen are de novo, one is inherited from a mosaic father, and four offspring from two families have a paternally inherited variant. Intragenic microdeletions, balanced structural rearrangements, frameshifts, and nonsense variants are predicted to inactivate the SOX6 variant allele. Four missense variants occur in residues and protein regions highly conserved evolutionarily. These variants are not detected in the gnomAD control cohort, and the amino acid substitutions are predicted to be damaging. Two of these variants are located in the HMG domain and abolish SOX6 transcriptional activity in vitro. No clear genotype-phenotype correlations are found. Taken together, these findings concur that SOX6 haploinsufficiency leads to a neurodevelopmental SOXopathy that often includes ADHD and abnormal skeletal and other features.

Immuno-modulating properties of Tulathromycin in porcine monocyte-derived macrophages infected with porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome virus (PRRSV) is a positive-stranded RNA virus that grows in macrophages and causes acute pneumonia in pigs. PRRSV causes devastating losses to the porcine industry. However, due to its high antigenic variability and poorly understood immunopathogenesis, there is currently no effective vaccine or treatment to control PRRSV infection. The common occurrence of PRRSV infection with bacterial infections as well as its inflammatory-driven pathobiology raises the question of the value of antibiotics with immunomodulating properties for the treatment of the disease it causes. The macrolide antibiotic Tulathromycin (TUL) has been found to exhibit potent anti-inflammatory and immunomodulating properties in cattle and pigs. The aim of this study was to characterize the anti-viral and immunomodulating properties of TUL in PRRSV-infected porcine macrophages. Our findings indicate that blood monocyte-derived macrophages are readily infected by PRRSV and can be used as an effective cellular model to study PRRSV pathogenesis. TUL did not change intracellular or extracellular viral titers, not did it alter viral receptors (CD163 and CD169) expression on porcine macrophages. In contrast, TUL exhibited potent immunomodulating properties, which therefore occurred in the absence of any direct antiviral effects against PRRSV. TUL had an additive effect with PRRSV on the induction of macrophage apoptosis, and inhibited virus-induced necrosis. TUL significantly attenuated PRRSV-induced macrophage pro-inflammatory signaling (CXCL-8 and mitochondrial ROS production) and prevented PRRSV inhibition of non-opsonized and opsonized phagocytic function. Together, these data demonstrate that TUL inhibits PRRSV-induced inflammatory responses in porcine macrophages and protects against the phagocytic impairment caused by the virus. Research in live pigs is warranted to assess the potential clinical benefits of this antibiotic in the context of virally induced inflammation and tissue injury.

A novel role of astrocyte elevated gene-1 (AEG-1) in regulating nonalcoholic steatohepatitis (NASH)

Nonalcoholic steatohepatitis (NASH) is the most prevalent cause of chronic liver disease in the Western world. However, an optimum therapy for NASH is yet to be established, mandating more in-depth investigation into the molecular pathogenesis of NASH to identify novel regulatory molecules and develop targeted therapies. Here, we unravel a unique function of astrocyte elevated gene-1(AEG-1)/metadherin in NASH using a transgenic mouse with hepatocyte-specific overexpression of AEG-1 (Alb/AEG-1) and a conditional hepatocyte-specific AEG-1 knockout mouse (AEG-1^ΔHEP ). Alb/AEG-1 mice developed spontaneous NASH whereas AEG-1^ΔHEP mice were protected from high-fat diet (HFD)-induced NASH. Intriguingly, AEG-1 overexpression was observed in livers of NASH patients and wild-type (WT) mice that developed steatosis upon feeding HFD. In-depth molecular analysis unraveled that inhibition of peroxisome proliferator-activated receptor alpha activity resulting in decreased fatty acid β-oxidation, augmentation of translation of fatty acid synthase resulting in de novo lipogenesis, and increased nuclear factor kappa B-mediated inflammation act in concert to mediate AEG-1-induced NASH. Therapeutically, hepatocyte-specific nanoparticle-delivered AEG-1 small interfering RNA provided marked protection from HFD-induced NASH in WT mice.

CONCLUSION

AEG-1 might be a key molecule regulating initiation and progression of NASH. AEG-1 inhibitory strategies might be developed as a potential therapeutic intervention in NASH patients. (Hepatology 2017;66:466-480).

Oncogenic Role of SND1 in Development and Progression of Hepatocellular Carcinoma

SND1, a subunit of the miRNA regulatory complex RISC, has been implicated as an oncogene in hepatocellular carcinoma (HCC). In this study, we show that hepatocyte-specific SND1 transgenic mice (Alb/SND1 mice) develop spontaneous HCC with partial penetrance and exhibit more highly aggressive HCC induced by chemical carcinogenesis. Livers from Alb/SND1 mice exhibited a relative increase in inflammatory markers and spheroid-generating tumor-initiating cells (TIC). Mechanistic investigations defined roles for Akt and NF-κB signaling pathways in promoting TIC formation in Alb/SND1 mice. In human xenograft models of subcutaneous or orthotopic HCC, administration of the selective SND1 inhibitor 3', 5'-deoxythymidine bisphosphate (pdTp), inhibited tumor formation without effects on body weight or liver function. Our work establishes an oncogenic role for SND1 in promoting TIC formation and highlights pdTp as a highly selective SND1 inhibitor as a candidate therapeutic lead to treat advanced HCC. Cancer Res; 77(12); 3306-16. ©2017 AACR.

Small molecule inhibitors of Late SV40 Factor (LSF) abrogate hepatocellular carcinoma (HCC): Evaluation using an endogenous HCC model

Hepatocellular carcinoma (HCC) is a lethal malignancy with high mortality and poor prognosis. Oncogenic transcription factor Late SV40 Factor (LSF) plays an important role in promoting HCC. A small molecule inhibitor of LSF, Factor Quinolinone Inhibitor 1 (FQI1), significantly inhibited human HCC xenografts in nude mice without harming normal cells. Here we evaluated the efficacy of FQI1 and another inhibitor, FQI2, in inhibiting endogenous hepatocarcinogenesis. HCC was induced in a transgenic mouse with hepatocyte-specific overexpression of c-myc (Alb/c-myc) by injecting N-nitrosodiethylamine (DEN) followed by FQI1 or FQI2 treatment after tumor development. LSF inhibitors markedly decreased tumor burden in Alb/c-myc mice with a corresponding decrease in proliferation and angiogenesis. Interestingly, in vitro treatment of human HCC cells with LSF inhibitors resulted in mitotic arrest with an accompanying increase in CyclinB1. Inhibition of CyclinB1 induction by Cycloheximide or CDK1 activity by Roscovitine significantly prevented FQI-induced mitotic arrest. A significant induction of apoptosis was also observed upon treatment with FQI. These effects of LSF inhibition, mitotic arrest and induction of apoptosis by FQI1s provide multiple avenues by which these inhibitors eliminate HCC cells. LSF inhibitors might be highly potent and effective therapeutics for HCC either alone or in combination with currently existing therapies.

Tetraspanin 8 mediates AEG-1-induced invasion and metastasis in hepatocellular carcinoma cells

Astrocyte-elevated gene-1 (AEG-1) positively regulates tumor progression and metastasis. Here, we document that AEG-1 upregulates transcription of the membrane protein tetraspanin 8 (TSPAN8). Knocking down TSPAN8 in AEG-1-overexpressing human hepatocellular carcinoma (HCC) cells markedly inhibited invasion and migration without affecting proliferation. TSPAN8 knockdown profoundly abrogated AEG-1-induced primary tumor and intrahepatic metastasis in an orthopic xenograft model in athymic nude mice. Coculture of TSPAN8 knockdown cells with human umbilical vein endothelial cells (HUVEC) markedly inhibited HUVEC tube formation indicating that inhibition of angiogenesis might cause reduction in primary tumor size. TSPAN8 inhibition might be a potential therapeutic strategy for metastatic HCC.

Abstract 5400: A novel combinatorial therapy for hepatocellular carcinoma (HCC)

The incidence of hepatocellular carcinoma (HCC) is rising in the US with parallel increase in mortality rate. Lack of effective therapy for advanced HCC mandates development of novel targeted therapies to counteract this fatal malady. Astrocyte elevated gene-1 (AEG-1), also known as metadherin (MTDH) and LYRIC, plays a pivotal role in hepatocarcinogenesis and serves as an ideal target for anti-HCC therapy. AEG-1 interacts with retinoid X receptor (RXR) and inhibits retinoic acid-induced gene expression and cell death. Retinoic acid has been evaluated for HCC treatment without promising result. Overexpression of AEG-1 might underlie the poor performance of retinoic acid in HCC clinical trials. We documented that combination of a lentivirus expressing AEG-1 shRNA (lenti.shAEG-1) and all-trans retinoic acid (ATRA) profoundly and synergistically inhibited subcutaneous human HCC xenografts in nude mice. We now have developed liver-targeted nanoplexes by conjugating poly(amidoamine) (PAMAM) dendrimers with polyethylene glycol (PEG) and lactobionic acid (PAMAM-PEG-Gal) which were complexed with AEG-1 siRNA (PAMAM-AEG-1si). PAMAM has a net positive charge that complexes with the net negative charge of the siRNA backbone, PEG increases stability of the nanoplexes and increases circulation time and the galactose binds to asialoglycoprotein receptors that are upregulated on liver cells. The polymer conjugate was characterized by 1H-NMR and optimal nanoplex formulations were characterized for surface charge and size using a zetasizer Nano ZS. We established orthotopic xenografts of human HCC cell QGY-7703 expressing luciferase (QGY-luc) in the livers of athymic nude mice and monitored tumor development by bioluminescence imaging (BLI). One week after tumor establishment mice were treated with PAMAM-siCon, PAMAM-siCon+ATRA, PAMAM-AEG-1si and PAMAM-AEG-1si+ATRA by 8 i.v. injections over 4 weeks, and sacrificed 2 weeks after the last injection. In the control group the tumor developed aggressively. ATRA showed little effect due to high AEG-1 levels in QGY-luc cells. PAMAM-AEG-1si showed significant reduction in tumor growth and the combination of PAMAM-AEG-1si+ATRA showed profound and synergistic inhibition so that the tumors were almost undetectable by BLI. Measurement of liver weight at the end of the experiment corroborated these findings. Analysis of AEG-1 mRNA in tumor samples showed a marked decrease in AEG-1 level by PAMAM-AEG-1si indicating efficacy of in vivo knockdown. The group treated with PAMAM-AEG-1si+ATRA nanoplexes showed increased necrosis, inhibition of proliferation and increased apoptosis when compared to other groups. Liver is an ideal organ for RNAi therapy and ATRA is an approved anti-cancer agent. Our exciting observations suggest that the combinatorial approach might be an effective way to combat HCC and need to be evaluated stringently in endogenous mouse models of HCC for a potential Phase I/II clinical trial.

Citation Format: Jyoti Srivastava, Devaraja Rajasekaran, Ayesha Siddiq, Rachel Gredler, Chadia L. Robertson, Maaged A. Akiel, Xue-Ning Shen, Kareem A.N. Ebeid, Aliasger K. Salem, Paul B. Fisher, Devanand Sarkar. A novel combinatorial therapy for hepatocellular carcinoma (HCC). [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 5400. doi:10.1158/1538-7445.AM2015-5400

The role of AEG-1 in the development of liver cancer

AEG-1 is an oncogene that is overexpressed in all cancers, including hepatocellular carcinoma. AEG-1 plays a seminal role in promoting cancer development and progression by augmenting proliferation, invasion, metastasis, angiogenesis and chemoresistance, all hallmarks of aggressive cancer. AEG-1 mediates its oncogenic function predominantly by interacting with various protein complexes. AEG-1 acts as a scaffold protein, activating multiple protumorigenic signal transduction pathways, such as MEK/ERK, PI3K/Akt, NF-κB and Wnt/β-catenin while regulating gene expression at transcriptional, post-transcriptional and translational levels. Our recent studies document that AEG-1 is fundamentally required for activation of inflammation. A comprehensive and convincing body of data currently points to AEG-1 as an essential component critical to the onset and progression of cancer. The present review describes the current knowledge gleaned from patient and experimental studies as well as transgenic and knockout mouse models, on the impact of AEG-1 on hepatocarcinogenesis.

Combination of Nanoparticle-Delivered siRNA for Astrocyte Elevated Gene-1 (AEG-1) and All-trans Retinoic Acid (ATRA): An Effective Therapeutic Strategy for Hepatocellular Carcinoma (HCC)

Hepatocellular carcinoma (HCC) is a fatal cancer with no effective therapy. Astrocyte elevated gene-1 (AEG-1) plays a pivotal role in hepatocarcinogenesis and inhibits retinoic acid-induced gene expression and cell death. The combination of a lentivirus expressing AEG-1 shRNA and all-trans retinoic acid (ATRA) profoundly and synergistically inhibited subcutaneous human HCC xenografts in nude mice. We have now developed liver-targeted nanoplexes by conjugating poly(amidoamine) (PAMAM) dendrimers with polyethylene glycol (PEG) and lactobionic acid (Gal) (PAMAM-PEG-Gal) which were complexed with AEG-1 siRNA (PAMAM-AEG-1si). The polymer conjugate was characterized by (1)H-NMR, MALDI, and mass spectrometry; and optimal nanoplex formulations were characterized for surface charge, size, and morphology. Orthotopic xenografts of human HCC cell QGY-7703 expressing luciferase (QGY-luc) were established in the livers of athymic nude mice and tumor development was monitored by bioluminescence imaging (BLI). Tumor-bearing mice were treated with PAMAM-siCon, PAMAM-siCon+ATRA, PAMAM-AEG-1si, and PAMAM-AEG-1si+ATRA. In the control group the tumor developed aggressively. ATRA showed little effect due to high AEG-1 levels in QGY-luc cells. PAMAM-AEG-1si showed significant reduction in tumor growth, and the combination of PAMAM-AEG-1si+ATRA showed profound and synergistic inhibition so that the tumors were almost undetectable by BLI. A marked decrease in AEG-1 level was observed in tumor samples treated with PAMAM-AEG-1si. The group treated with PAMAM-AEG-1si+ATRA nanoplexes showed increased necrosis, inhibition of proliferation, and increased apoptosis when compared to other groups. Liver is an ideal organ for RNAi therapy and ATRA is an approved anticancer agent. Our exciting observations suggest that the combinatorial approach might be an effective way to combat HCC.

Astrocyte Elevated Gene-1 (AEG-1) Regulates Lipid Homeostasis

Astrocyte elevated gene-1 (AEG-1), also known as MTDH (metadherin) or LYRIC, is an established oncogene. However, the physiological function of AEG-1 is not known. To address this question, we generated an AEG-1 knock-out mouse (AEG-1KO) and characterized it. Although AEG-1KO mice were viable and fertile, they were significantly leaner with prominently less body fat and lived significantly longer compared with wild type (WT). When fed a high fat and cholesterol diet (HFD), WT mice rapidly gained weight, whereas AEG-1KO mice did not gain weight at all. This phenotype of AEG-1KO mice is due to decreased fat absorption from the intestines, not because of decreased fat synthesis or increased fat consumption. AEG-1 interacts with retinoid X receptor (RXR) and inhibits RXR function. In enterocytes of AEG-1KO mice, we observed increased activity of RXR heterodimer partners, liver X receptor and peroxisome proliferator-activated receptor-α, key inhibitors of intestinal fat absorption. Inhibition of fat absorption in AEG-1KO mice was further augmented when fed an HFD providing ligands to liver X receptor and peroxisome proliferator-activated receptor-α. Our studies reveal a novel role of AEG-1 in regulating nuclear receptors controlling lipid metabolism. AEG-1 may significantly modulate the effects of HFD and thereby function as a unique determinant of obesity.

Astrocyte Elevated Gene-1 (AEG-1) Contributes to Non-thyroidal Illness Syndrome (NTIS) Associated with Hepatocellular Carcinoma (HCC)

Non-thyroidal illness syndrome (NTIS), characterized by low serum 3,5,3'-triiodothyronine (T3) with normal l-thyroxine (T4) levels, is associated with malignancy. Decreased activity of type I 5'-deiodinase (DIO1), which converts T4 to T3, contributes to NTIS. T3 binds to thyroid hormone receptor, which heterodimerizes with retinoid X receptor (RXR) and regulates transcription of target genes, such as DIO1. NF-κB activation by inflammatory cytokines inhibits DIO1 expression. The oncogene astrocyte elevated gene-1 (AEG-1) inhibits RXR-dependent transcription and activates NF-κB. Here, we interrogated the role of AEG-1 in NTIS in the context of hepatocellular carcinoma (HCC). T3-mediated gene regulation was analyzed in human HCC cells, with overexpression or knockdown of AEG-1, and primary hepatocytes from AEG-1 transgenic (Alb/AEG-1) and AEG-1 knock-out (AEG-1KO) mice. Serum T3 and T4 levels were checked in Alb/AEG-1 mice and human HCC patients. AEG-1 and DIO1 levels in human HCC samples were analyzed by immunohistochemistry. AEG-1 inhibited T3-mediated gene regulation in human HCC cells and mouse hepatocytes. AEG-1 overexpression repressed and AEG-1 knockdown induced DIO1 expression. An inverse correlation was observed between AEG-1 and DIO1 levels in human HCC patients. Low T3 with normal T4 was observed in the sera of HCC patients and Alb/AEG-1 mice. Inhibition of co-activator recruitment to RXR and activation of NF-κB were identified to play a role in AEG-1-mediated down-regulation of DIO1. AEG-1 thus might play a role in NTIS associated with HCC and other cancers.

Astrocyte elevated gene-1 and c-Myc cooperate to promote hepatocarcinogenesis in mice

Astrocyte elevated gene-1 (AEG-1) and c-Myc are overexpressed in human hepatocellular carcinoma (HCC) functioning as oncogenes. AEG-1 is transcriptionally regulated by c-Myc, and AEG-1 itself induces c-Myc by activating the Wnt/β-catenin-signaling pathway. We now document the cooperation of AEG-1 and c-Myc in promoting hepatocarcinogenesis by analyzing hepatocyte-specific transgenic mice expressing either AEG-1 (albumin [Alb]/AEG-1), c-Myc (Alb/c-Myc), or both (Alb/AEG-1/c-Myc). Wild-type and Alb/AEG-1 mice did not develop spontaneous HCC. Alb/c-Myc mice developed spontaneous HCC without distant metastasis, whereas Alb/AEG-1/c-Myc mice developed highly aggressive HCC with frank metastasis to the lungs. Induction of carcinogenesis by N-nitrosodiethylamine significantly accelerated the kinetics of tumor formation in all groups. However, in Alb/AEG-1/c-Myc, the effect was markedly pronounced with lung metastasis. In vitro analysis showed that Alb/AEG-1/c-Myc hepatocytes acquired increased proliferation and transformative potential with sustained activation of prosurvival and epithelial-mesenchymal transition-signaling pathways. RNA-sequencing analysis identified a unique gene signature in livers of Alb/AEG-1/c-Myc mice that was not observed when either AEG-1 or c-Myc was overexpressed. Specifically, Alb/AEG-1/c-Myc mice overexpressed maternally imprinted noncoding RNAs (ncRNAs), such as Rian, Meg-3, and Mirg, which are implicated in hepatocarcinogenesis. Knocking down these ncRNAs significantly inhibited proliferation and invasion by Alb/AEG-1/c-Myc hepatocytes.

CONCLUSION

Our studies reveal a novel cooperative oncogenic effect of AEG-1 and c-Myc that might explain the mechanism of aggressive HCC. Alb/AEG-1/c-Myc mice provide a useful model to understand the molecular mechanism of cooperation between these two oncogenes and other molecules involved in hepatocarcinogenesis. This model might also be of use for evaluating novel therapeutic strategies targeting HCC.

AEG-1 regulates retinoid X receptor and inhibits retinoid signaling

Retinoid X receptor (RXR) regulates key cellular responses such as cell growth and development, and this regulation is frequently perturbed in various malignancies, including hepatocellular carcinoma (HCC). However, the molecule(s) that physically govern this deregulation are mostly unknown. Here, we identified RXR as an interacting partner of astrocyte-elevated gene-1 (AEG-1)/metadherin (MTDH), an oncogene upregulated in all cancers. Upon interaction, AEG-1 profoundly inhibited RXR/retinoic acid receptor (RAR)-mediated transcriptional activation. Consequently, AEG-1 markedly protected HCC and acute myelogenous leukemia (AML) cells from retinoid- and rexinoid-induced cell death. In nontumorigenic cells and primary hepatocytes, AEG-1/RXR colocalizes in the nucleus in which AEG-1 interferes with recruitment of transcriptional coactivators to RXR, preventing transcription of target genes. In tumor cells and AEG-1 transgenic hepatocytes, overexpressed AEG-1 entraps RXR in cytoplasm, precluding its nuclear translocation. In addition, ERK, activated by AEG-1, phosphorylates RXR that leads to its functional inactivation and attenuation of ligand-dependent transactivation. In nude mice models, combination of all-trans retinoic acid (ATRA) and AEG-1 knockdown synergistically inhibited growth of human HCC xenografts. The present study establishes AEG-1 as a novel homeostatic regulator of RXR and RXR/RAR that might contribute to hepatocarcinogenesis. Targeting AEG-1 could sensitize patients with HCC and AML to retinoid- and rexinoid-based therapeutics.

Abstract 72: Analyzing the role of Astrocyte Elevated Gene-1 (AEG-1) in hepatocarcinogenesis using a knockout mouse model

The oncogene Astrocyte Elevated Gene-1 (AEG-1) is overexpressed in a wide variety of human cancers. In vitro and in vivo nude mouse xenograft studies have established the tumor-promoting role of AEG-1. Activation of multiple signaling pathways, such as NF-κB, PI3K/Akt, Wnt/β-catenin and MEK/ERK, has been attributed to mediate oncogenesis by AEG-1. To better understand the role AEG-1 plays in the onset and progression of cancer and to identify key mechanism(s) of AEG-1 action, we generated a novel AEG-1 knockout mouse (AEG-1-/-). We studied hepatocarcinogenesis in this model because AEG-1 is overexpressed in more than 90% of human hepatocellular carcinoma (HCC) patients and is believed to play a key regulatory role in progression of the disease. AEG-1-/- mice were viable with normal development. We first compared the aging associated phenotype of WT and AEG-1-/- mice. At 16 months of age spontaneous tumor development in lungs and liver was observed in some cohorts of untreated WT mice (n=20). Such tumorigenesis was not detected in any of the AEG-1-/- mice. Additionally, age-associated inflammatory infiltrates were observed in the internal organs of WT but not AEG-1-/- mice. To initiate HCC, WT and AEG-1-/- mice were treated with diethylnitrosamine (DEN) at 2 weeks of age. At 32 weeks WT mice showed a marked hepatocarcinogenic response while AEG-1-/- mice exhibited profound resistance to tumor formation. The hepatocarcinogenic response was further evaluated by DEN initiation followed by daily phenobarbital treatment. WT mice exhibited an intensified hepatocarcinogenic response evidenced by large necrotic liver tumors at 28 weeks of age with a 52% rate of lung metastasis. AEG-1-/- mice remained remarkably resistant even to this combinatorial treatment with no distant metastasis. No difference in the activation of Akt, ERK and β-catenin signaling was observed between WT and AEG-1-/- mice indicating that these pathways may not be regulated by AEG-1 under physiological conditions. However, marked inhibition of NF-κB activation was observed in AEG-1-/- mice. Lipopolysaccharide (LPS)-induced NF-κB luciferase reporter activity, nuclear translocation of p65 subunit of NF-κB and induction of IL-1β and IL-6 were markedly attenuated in primary hepatocytes and macrophages isolated from AEG-1-/- versus WT mice. Chronic inflammation and NF-κB activation play a causal role in hepatocarcinogenesis. Inhibition of NF-κB activation in hepatocytes and macrophages profoundly abrogates HCC development in mouse models. Our findings in AEG-1-/- mice confirm a fundamental role of AEG-1 in NF-κB activation. Here we demonstrate that lack of AEG-1 protects from generalized inflammation thereby suppressing spontaneous as well as experimental tumorigenesis. AEG-1-/-mice might be a useful model to study inflammation and cancer in diverse organ systems.

Citation Format: Chadia L. Robertson, Jyoti Srivastava, Ayesha Siddiq, Rachel Gredler, Devaraja Rajasekaran, Maaged Akiel, Xue-Ning Shen, Knarik Arkun, Shobha Ghosh, Mark A. Subler, Jolene Windle, Paul B. Fisher, Devanand Sarkar. Analyzing the role of Astrocyte Elevated Gene-1 (AEG-1) in hepatocarcinogenesis using a knockout mouse model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 72. doi:10.1158/1538-7445.AM2014-72

Genetic deletion of AEG-1 prevents hepatocarcinogenesis

Activation of the oncogene AEG-1 (MTDH, LYRIC) has been implicated recently in the development of hepatocellular carcinoma (HCC). In mice, HCC can be initiated by exposure to the carcinogen DEN, which has been shown to rely upon activation of NF-κB in liver macrophages. Because AEG-1 is an essential component of NF-κB activation, we interrogated the susceptibility of mice lacking the AEG-1 gene to DEN-induced hepatocarcinogenesis. AEG-1-deficient mice displayed resistance to DEN-induced HCC and lung metastasis. No difference was observed in the response to growth factor signaling or activation of AKT, ERK, and β-catenin, compared with wild-type control animals. However, AEG-1-deficient hepatocytes and macrophages exhibited a relative defect in NF-κB activation. Mechanistic investigations showed that IL6 production and STAT3 activation, two key mediators of HCC development, were also deficient along with other biologic and epigenetics findings in the tumor microenvironment, confirming that AEG-1 supports an NF-κB-mediated inflammatory state that drives HCC development. Overall, our findings offer in vivo proofs that AEG-1 is essential for NF-κB activation and hepatocarcinogenesis, and they reveal new roles for AEG-1 in shaping the tumor microenvironment for HCC development.

Emerging role of insulin-like growth factor-binding protein 7 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a vicious and highly vascular cancer with a dismal prognosis. It is a life-threatening illness worldwide that ranks fifth in terms of cancer prevalence and third in cancer deaths. Most patients are diagnosed at an advanced stage by which time conventional therapies are no longer effective. Targeted molecular therapies, such as the multikinase inhibitor sorafenib, provide a modest increase in survival for advanced HCC patients and display significant toxicity. Thus, there is an immense need to identify novel regulators of HCC that might be targeted effectively. The insulin-like growth factor (IGF) axis is commonly abnormal in HCC. Upon activation, the IGF axis controls metabolism, tissue homeostasis, and survival. Insulin-like growth factor-binding protein 7 (IGFBP7) is a secreted protein of a family of low-affinity IGF-binding proteins termed “IGFBP-related proteins” that have been identified as a potential tumor suppressor in HCC. IGFBP7 has been implicated in regulating cellular proliferation, senescence, and angiogenesis. In this review, we provide a comprehensive discussion of the role of IGFBP7 in HCC and the potential use of IGFBP7 as a novel biomarker for drug resistance and as an effective therapeutic strategy.

Abstract 5437: Astrocyte Elevated Gene-1 (AEG-1) interacts with retinoid X receptor (RXR) and abrogates its function

The oncogene Astrocyte Elevated Gene-1 (AEG-1), also known as Metadherin (MTDH), is overexpressed in a diverse array of cancers, including hepatocellular carcinoma (HCC), and plays an important role in promoting tumor development and progression. Protein-protein interaction predominantly mediates the tumor promoting effects of AEG-1. We now describe screening of a human liver cDNA library by yeast two hybrid assay resulting in identification of Retinoid X Receptor (RXR) as an AEG-1-interacting protein. Site-directed mutagenesis assays identified an LXXLL motif in the N-terminus of AEG-1 mediating interaction with RXR. We employed human HCC cell lines stably overexpressing AEG-1 or with knockdown of AEG-1 and mouse hepatocytes isolated from a transgenic mouse with hepatocyte-specific expression of AEG-1 (Alb/AEG-1) and from AEG-1 knockout (AEG-1 KO) mouse for our studies. Luciferase reporter assays in these cells demonstrate that AEG-1 profoundly inhibits RXR-mediated transcriptional regulation of its heterodimer partner, such as Retinoic Acid Receptor (RAR), Thyroid Hormone Receptor (TR), Liver X Receptor (LXR) and Peroxisome Proliferator-Activated Receptor (PPAR), in the presence or absence of their corresponding ligands. In this study, we focus on retinoic acid (RA) and thyroid hormone (T3) function. AEG-1 markedly inhibits expression of RA- and T3-induced genes. Overexpressed AEG-1 in cancer cells and in transgenic hepatocytes accumulates in the cytoplasm and inhibits RXR function by trapping RXR in the cytoplasm precluding its nuclear translocation. Additionally, AEG-1 induces phosphorylation of RXR, via ERK and p38 MAPK pathways. Phosphorylated RXR has low transcriptional activity, functions as dominant negative inhibitor of RXR and might facilitate hepatocarcinogenesis by AEG-1. Indeed, chromatin immunoprecipitation (ChIP) assay using RA-target genes, RARB and HOXA1, shows decreased DNA binding of RXR, even upon ligand-treatment. Overexpression of AEG-1 significantly protects human HCC cells, mouse hepatocytes and human promyelocytic leukemia cells from the killing effects of retinoic acid and its synthetic analogs. By inhibiting the expression of T3-regulated gene type I deiodinase (DIO1), AEG-1 abrogates peripheral conversion of inactive T4 to active T3 which is reflected by significantly low T3 level in the circulation of Alb/AEG-1 mice compared to WT mice. Since AEG-1 is upregulated in a wide-variety of cancers it might play an important role in regulating a diverse array of RXR-dependent signaling pathways that are critical for regulating the oncogenic process. Synthetic retinoids are being evaluated as chemopreventive agents for HCC as well as a therapeutic modality for PML. AEG-1 expression level might determine the sensitivity of the patients to these retinoids. Additionally AEG-1 might play a key role in ‘low T3 syndrome’ associated with cancer.

Citation Format: Jyoti Srivastava, Chadia L. Robertson, Rachel Gredler, Ayesha Siddiq, Devaraja Rajasekaran, Prasanna K. Santhekadur, Paul B. Fisher, Devanand Sarkar. Astrocyte Elevated Gene-1 (AEG-1) interacts with retinoid X receptor (RXR) and abrogates its function. [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 5437. doi:10.1158/1538-7445.AM2013-5437

Insulin-like growth factor-binding protein-7 (IGFBP7): a promising gene therapeutic for hepatocellular carcinoma (HCC)

Hepatocellular carcinoma (HCC) is a highly fatal disease mandating development of novel, targeted therapies to elicit prolonged survival benefit to the patients. Insulin-like growth factor-binding protein-7 (IGFBP7), a secreted protein belonging to the IGFBP family, functions as a potential tumor suppressor for HCC. In the present study, we evaluated the therapeutic efficacy of a replication-incompetent adenovirus expressing IGFBP7 (Ad.IGFBP7) in human HCC. Ad.IGFBP7 profoundly inhibited viability and induced apoptosis in multiple human HCC cell lines by inducing reactive oxygen species (ROS) and activating a DNA damage response (DDR) and p38 MAPK. In orthotopic xenograft models of human HCC in athymic nude mice, intravenous administration of Ad.IGFBP7 profoundly inhibited primary tumor growth and intrahepatic metastasis. In a nude mice subcutaneous model, xenografts from human HCC cells were established in both flanks and only left-sided tumors received intratumoral injection of Ad.IGFBP7. Growth of both left-sided injected tumors and right-sided uninjected tumors were markedly inhibited by Ad.IGFBP7 with profound suppression of angiogenesis. These findings indicate that Ad.IGFBP7 might be a potent therapeutic eradicating both primary HCC and distant metastasis and might be an effective treatment option for terminal HCC patients.

Astrocyte elevated gene-1 promotes hepatocarcinogenesis: novel insights from a mouse model

Astrocyte elevated gene-1 (AEG-1) is a key contributor to hepatocellular carcinoma (HCC) development and progression. To enhance our understanding of the role of AEG-1 in hepatocarcinogenesis, a transgenic mouse with hepatocyte-specific expression of AEG-1 (Alb/AEG1) was developed. Treating Alb/AEG-1, but not wild-type (WT) mice, with N-nitrosodiethylamine resulted in multinodular HCC with steatotic features and associated modulation of expression of genes regulating invasion, metastasis, angiogenesis, and fatty acid synthesis. Hepatocytes isolated from Alb/AEG-1 mice displayed profound resistance to chemotherapeutics and growth factor deprivation with activation of prosurvival signaling pathways. Alb/AEG-1 hepatocytes also exhibited marked resistance toward senescence, which correlated with abrogation of activation of a DNA damage response. Conditioned media from Alb/AEG-1 hepatocytes induced marked angiogenesis with elevation in several coagulation factors. Among these factors, AEG-1 facilitated the association of factor XII (FXII) messenger RNA with polysomes, resulting in increased translation. Short interfering RNA-mediated knockdown of FXII resulted in profound inhibition of AEG-1-induced angiogenesis.

CONCLUSION

We uncovered novel aspects of AEG-1 functions, including induction of steatosis, inhibition of senescence, and activation of the coagulation pathway to augment aggressive hepatocarcinogenesis. The Alb/AEG-1 mouse provides an appropriate model to scrutinize the molecular mechanism of hepatocarcinogenesis and to evaluate the efficacy of novel therapeutic strategies targeting HCC.

The transcription factor LSF: a novel oncogene for hepatocellular carcinoma

The transcription factor LSF (Late SV40 Factor), also known as TFCP2, belongs to the LSF/CP2 family related to Grainyhead family of proteins and is involved in many biological events, including regulation of cellular and viral promoters, cell cycle, DNA synthesis, cell survival and Alzheimer's disease. Our recent studies establish an oncogenic role of LSF in Hepatocellular carcinoma (HCC). LSF overexpression is detected in human HCC cell lines and in more than 90% cases of human HCC patients, compared to normal hepatocytes and liver, and its expression level showed significant correlation with the stages and grades of the disease. Forced overexpression of LSF in less aggressive HCC cells resulted in highly aggressive, angiogenic and multi-organ metastatic tumors in nude mice. Conversely, inhibition of LSF significantly abrogated growth and metastasis of highly aggressive HCC cells in nude mice. Microarray studies revealed that as a transcription factor LSF modulated specific genes regulating invasion, angiogenesis, chemoresistance and senescence. LSF transcriptionally regulates thymidylate synthase (TS) gene, thus contributing to cell cycle regulation and chemoresistance. Our studies identify a network of proteins, including osteopontin (OPN), Matrix metalloproteinase-9 (MMP-9), c-Met and complement factor H (CFH), that are directly regulated by LSF and play important role in LSF-induced hepatocarcinogenesis. A high throughput screening identified small molecule inhibitors of LSF DNA binding and the prototype of these molecules, Factor Quinolinone inhibitor 1 (FQI1), profoundly inhibited cell viability and induced apoptosis in human HCC cells without exerting harmful effects to normal immortal human hepatocytes and primary mouse hepatocytes. In nude mice xenograft studies, FQI1 markedly inhibited growth of human HCC xenografts as well as angiogenesis without exerting any toxicity. These studies establish a key role of LSF in hepatocarcinogenesis and usher in a novel therapeutic avenue for HCC, an invariably fatal disease.

Abstract 1324: Unraveling novel functions of the oncogene Astrocyte elevated gene-1 (AEG-1) contributing to hepatocarcinogenesis employing a transgenic mouse model

In vitro tissue culture and nude mice xenograft models have firmly established the role of Astrocyte elevated gene-1 (AEG-1) as a positive regulator of tumorigenesis, including hepatocarcinogenesis. To better appreciate the role of AEG-1 in hepatocarcinogenesis and to dissect the underlying molecular mechanism, we have created a transgenic mouse with hepatocyte-specific expression of AEG-1 (Alb/AEG1). Wild-type (WT) and Alb/AEG-1 mice were challenged with a hepatocarcinogen, N-nitrosodiethylamine (DEN), at 2 weeks of age. At 28 weeks of age, Alb/AEG-1 mice, but not WT mice, developed multinodular HCC with steatotic features and highly elevated serum liver enzymes. Affymetrix microarray analyses identified modulation of expression of genes associated with invasion, metastasis, angiogenesis and fatty acid synthesis in DEN-treated Alb/AEG-1 mice versus their WT counterparts. Hepatocytes isolated from Alb/AEG-1 mice demonstrated profound chemoresistance and dramatically evaded reduction in cell viability upon growth factor deprivation, which was associated with activation of multiple pro-survival signaling pathways. Compared to the WT hepatocytes, Alb/AEG-1 hepatocytes demonstrated marked resistance towards senescence, which was associated with abrogation of activation of a DNA damage response. Conditioned media (CM) from Alb/AEG-1 hepatocytes, but not form WT hepatocytes, induced marked angiogenesis. Mass spectrometric analysis of CM revealed noticeable increases in coagulation factors by AEG-1, which are known to play a significant role in regulating tumor invasion, angiogenesis and metastasis. siRNA-mediated knockdown of coagulation factor XII resulted in profound inhibition of AEG-1-induced angiogenesis. Our studies reveal novel aspects of AEG-1 functions, such as induction of steatosis, inhibition of senescence, a known anti-cancer mechanism, and activation of coagulation pathway to augment an aggressive hepatocarcinogenic phenotype. The Alb/AEG-1 mouse will be a useful model to decipher AEG-1 function in the context of hepatocarcinogenesis and to evaluate the efficacy of novel therapeutic strategies directed towards HCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1324. doi:1538-7445.AM2012-1324

Late SV40 factor (LSF) enhances angiogenesis by transcriptionally up-regulating matrix metalloproteinase-9 (MMP-9)

The transcription factor late SV40 factor (LSF) is overexpressed in human hepatocellular carcinoma (HCC) fostering a highly aggressive and metastatic phenotype. Angiogenesis is an essential component of cancer aggression and metastasis and HCC is a highly aggressive and angiogenic cancer. In the present studies, we analyzed the molecular mechanism of LSF-induced angiogenesis in HCC. Employing human umbilical vein endothelial cells (HUVEC) differentiation assay and chicken chorioallantoic membrane (CAM) assay we document that stable LSF overexpression augments and stable dominant negative inhibition of LSF (LSFdn) abrogates angiogenesis by human HCC cells. A quest for LSF-regulated factors contributing to angiogenesis, by chromatin immunoprecipitation-on-chip (ChIP-on-chip) assay, identified matrix metalloproteinase-9 (MMP-9) as a direct target of LSF. MMP-9 expression and enzymatic activity were higher in LSF-overexpressing cells and lower in LSFdn-expressing cells. Deletion mutation analysis identified the LSF-responsive regions in the MMP-9 promoter and ChIP assay confirmed LSF binding to the MMP-9 promoter. Inhibition of MMP-9 significantly abrogated LSF-induced angiogenesis as well as in vivo tumorigenesis, thus reinforcing the role of MMP-9 in facilitating LSF function. The present findings identify a novel target of LSF contributing to its oncogenic properties.

Single nucleotide polymorphisms in the neuropeptide Y2 receptor (NPY2R) gene and association with severe obesity in French white subjects

AIMS/HYPOTHESIS

Genetic variants of genes for peptide YY (PYY), neuropeptide Y2 receptor (NPY2R) and pancreatic polypeptide (PPY) were investigated for association with severe obesity.

SUBJECTS AND METHODS

The initial screening of the genes for variants was performed by sequencing in a group of severely obese subjects (n=161). Case-control analysis of the common variants was then carried out in 557 severely obese adults, 515 severely obese children and 1,163 non-obese/non-diabetic control subjects. Rare variants were genotyped in 700 obese children and the non-obese/non-diabetic control subjects (n=1,163).

RESULTS

Significant association was found for a 5' variant (rs6857715) in the NPY2R gene with both severe adult obesity (p=0.002) and childhood obesity (p=0.02). This significant association was further supported by a pooled allelic analysis of all obese cases (adults and children, n=928) vs the control subjects (n=938) (p=0.0004, odds ratio=1.3, 95% CI 1.1-1.5). Quantitative trait analysis of BMI and WHR was performed and significant association was observed for SNP rs1047214 in NPY2R with an increase in WHR in the severely obese children (co-dominant model p=0.005, recessive model p=0.001). Association was also observed for an intron 3 variant (rs162430) in the PYY gene with childhood obesity (p=0.04). No significant associations were observed for PPY variants. Only one rare variant in the NPY2R gene (C-5641T) was not found in lean individuals and this was found to co-segregate with obesity in one family.

CONCLUSIONS/INTERPRETATION

These results provide evidence of association for NPY2R and PYY gene variants with obesity and none for PPY variants. A rare variant of the NPY2R gene showed evidence of co-segregation with obesity and its contribution to obesity should be investigated further.

Loss of IRF-4-binding protein leads to the spontaneous development of systemic autoimmunity

IFN regulatory factor 4-binding (IRF-4-binding) protein (IBP) is a novel type of activator of Rho GTPases that is recruited to the immunological synapse upon TCR stimulation. Here we demonstrate that loss of IBP leads to the spontaneous development of a systemic autoimmune disorder characterized by the accumulation of effector/memory T cells and IgG+ B cells, profound hypergammaglobulinemia, and autoantibody production. Similar to human SLE, this syndrome primarily affects females. T cells from IBP-deficient mice are resistant to death in vitro as well as in vivo and exhibit selective defects in effector function. In the absence of IBP, T cells respond suboptimally to TCR engagement, as demonstrated by diminished ERK1/2 activation, decreased c-Fos induction, impaired immunological synapse formation, and defective actin polymerization. Transduction of IBP-deficient T cells with a WT IBP protein, but not with an IBP mutant lacking the Dbl-like domain required for Rho GTPase activation, rescues the cytoskeletal defects exhibited by these cells. Collectively, these findings indicate that IBP, a novel regulator of Rho GTPases, is required for optimal T cell effector function, lymphocyte homeostasis, and the prevention of systemic autoimmunity.

A 2-year follow-up of orphans' competence, socioemotional problems and post-traumatic stress symptoms in traditional foster care and orphanages in Iraqi Kurdistan

BACKGROUND

This paper aims to compare orphans' development in two different care systems.

METHODS

Based on age, sex, psychological trauma scores, competence and psychological problem scores, two comparable samples were found representing orphans in the traditional foster care (n = 94) and the orphanages (n = 48) in a middle-large city in Iraqi Kurdistan. At an index interview, Child Behaviour Checklist (CBCL), Harvard-Uppsala Trauma Questionnaire for Children and Post-traumatic Stress Symptoms for Children (PTSS-C) were administered to the caregivers. After 1 year the CBCL, and after 2 years both the CBCL and the PTSS-C, were-re-administered, consecutively.

RESULTS

Although both samples revealed significant decrease in the means of total competence and problem scores over time, the improvement in activity scale, externalizing problem scores and post-traumatic stress disorder-related symptoms proved to be more significant in the foster care than in the orphanages. While the activity scale improved in the foster care, the school competence deteriorated in both samples, particularly among the girls in the orphanages. The improvement of boys' activity scores in the foster care, and deterioration of girls' school competence in the orphanages were the most significant gender differences between samples over time.

CONCLUSIONS

Even if the two orphan care systems showed more similarities than differences, the foster care revealed better outcomes over time. The results are discussed in relation to gender, age, socio-economic situation, cultural values and the characteristics of each care system.

Alterations in metabolism and gap junction expression may determine the role of astrocytes as ?good samaritans? or executioners

Our knowledge of astroglia and their physiological and pathophysiological role(s) in the central nervous system (CNS) has grown during the past decade, revealing a complex picture. It is becoming increasingly clear that glia play a significant role in the homeostasis and function of the CNS and that neurons should no longer be considered the only cell type that responds, both rapidly and slowly, to electrochemical activity. We discuss recent advances in the field with an emphasis on the impact of hypoxia and ischemia on astrocytic metabolism and the functional relationship between glucose metabolism and gap junctions in astrocytes. We also address the controversy over whether astrocytic gap junctions mediate protection or killing of neurons during or after hypoxic or ischemic insults.

The human homolog of Diminuto/Dwarf1 gene (hDiminuto): a novel ACTH-responsive gene overexpressed in benign cortisol-producing adrenocortical adenomas

To elucidate the molecular mechanism of the pathogenesis of benign functioning adrenocortical adenomas causing Cushing's syndrome, we employed suppression PCR-based cDNA subtractive hybridization to identify novel genes that are differentially expressed in the adenoma. In this report we describe the adenoma-specific overexpression of the human homolog of the Diminuto/Dwarf1 (hDiminuto) gene. Northern blot analysis revealed that hDiminuto mRNA was overexpressed in the adenoma tissue of 14 patients with Cushing's syndrome in comparison to the adjacent nontumorous adrenal gland. In situ hybridization using hDiminuto cRNA probe showed its abundant expression in the tumor cells, whereas the nontumorous cells showed a low level of expression. As the atrophic adjacent gland may not represent the normal architecture, we examined the expression pattern of hDiminuto mRNA in normal human adrenal cortex. In situ hybridization revealed that it was expressed in all layers of the normal adrenal cortex. In situ apoptosis detection by the TUNEL method revealed that a low level of hDiminuto expression in the atrophic, adjacent gland was associated with numerous TUNEL-positive cells in all layers of cortex. In contrast almost no apoptotic cell was detected in the tumor or in the normal adrenal cortex where hDiminuto expression was abundant. These results are compatible with a recent report that hDiminuto acts as an antiapoptotic factor in neurons. The expression of hDiminuto in the normal adrenal cortex was most abundant in the zona fasciculata, suggesting its possible regulation by ACTH/cAMP. Indeed, forskolin treatment of H295R human adrenocortical cells resulted in a significant induction of the mRNA in a time- and dose-dependent manner. To further demonstrate the physiological regulation, an in vivo experiment was carried out in dexamethasone-treated rats. ACTH administration to these rats increased the mRNA expression. These results led us to speculate that the overexpression of hDiminuto in the adenoma could be due to the abundant expression of ACTH receptor, as we previously described. Diminuto is involved in steroid synthesis and cell elongation in plants. We, therefore, hypothesize that hDiminuto might be involved in the molecular events of adrenocortical tumorigenesis by facilitating steroid synthesis and cell growth.

UT841 purified from sea urchin (Toxopneustes pileolus) venom inhibits time-dependent (45)Ca(2+) uptake in crude synaptosome fraction from chick brain

To clarify the mechanism by which the toxic abstract from Toxopneustes pileolus inhibits time-dependent (Time-dep.) Ca(2+) uptake in crude synaptosome fraction, the effective component from pedicellarial venom of the sea urchin was purified. The crude extracts were purified by a series of steps including ion exchange (DEAE-sephadex-A25 gel), gel filtration (with Superdex-2000 and Superdex-peptide columns) and reversed-phase chromatography (Sephasil-C18 column). The effective component that inhibited Time-dep. 45Ca(2+) uptake was purified and named UT841. Its IC(50) was determined to be lower than 35ng/ml. UT841 is an acidic protein with an apparent molecular weight of about 18,000. The N-terminal sequence (40 amino acids) was almost identical to that of Contractin A (a protein purified from the same kind of venom which induces smooth muscle contraction). Even though it is unclear whether or not UT841 is Contractin A, Ca(2+) mobilization in nerve cells was shown to be influenced by UT841. This investigation also revealed that a donor of nitric oxide, arachidonic acid and an inhibitor of phospholipase C selectively inhibit Time-dep. (45)Ca(2+) uptake. These results suggest that UT841 purified from sea urchin venom may affect Time-dep. (45)Ca(2+) uptake through the metabolism of some lipids and nitric oxide.

Expression of ZAKI-4 messenger ribonucleic acid in the brain during rat development and the effect of hypothyroidism

We identified ZAKI-4 (also designated as DSCR1L1) as a thyroid hormone responsive gene in cultured human skin fibroblasts. Recently it has been reported that ZAKI-4 belongs to an evolutionary conserved family of proteins that function as calcineurin inhibitor. In human, ZAKI-4 and calcineurin are highly expressed in brain, where thyroid hormones play essential roles in the development during fetal and neonatal periods. In the present study, we examined the temporal and spatial expression patterns of ZAKI-4 messenger RNA (mRNA) in control and hypothyroid rat brains. Northern blot analysis revealed that ZAKI-4 mRNA was detected in both cerebral cortex and cerebellum as early as embryonic day (E)18. In the cerebral cortex, the expression level gradually increased with age, reaching a plateau at postnatal day (P)7 and remained constant thereafter until P30. A similar pattern of increase with age was also observed in hypothyroid rats; however, the magnitude of the increase was significantly reduced. In control rats, the fold increase in ZAKI-4 mRNA level from E18 to P17 was 10.8; whereas in hypothyroid rats, it was 7.4. In cerebellum the expression level did not change with age or by thyroid status. In situ hybridization revealed that ZAKI-4 mRNA is widely expressed in neurons throughout the brain. It is noteworthy that the expression in the neurons of layer VI of the cerebral cortex was more evident in control rats than that in hypothyroid rats from P17 to P30. Though not influenced by hypothyroidism, there were several regions of the brain in which ZAKI-4 mRNA was strongly expressed. These regions were the mitral cell layer of the olfactory bulb, the substantia nigra, and the hippocampus, where calcineurin is also abundantly expressed. Therefore, it may be hypothesized that ZAKI-4 plays an important role in the development and function of the brain by modulating calcineurin function; and decrease in ZAKI-4 mRNA expression in the specific brain areas may explain, in some parts, the mechanism of abnormal brain development by hypothyroidism.