A G316A Polymorphism in the Ornithine Decarboxylase Gene Promoter Modulates MYCN-Driven Childhood Neuroblastoma

Simple Summary

Neuroblastoma is a devasting childhood cancer in which multiple copies (amplification) of the cancer-causing gene MYCN strongly predict poor outcome. Neuroblastomas are reliant on high levels of cellular components called polyamines for their growth and malignant behavior, and the gene regulating polyamine synthesis is called ODC1. ODC1 is often coamplified with MYCN, and in fact is regulated by MYCN, and like MYCN is prognostic of poor outcome. Here we studied a naturally occurring genetic variant or polymorphism that occurs in the ODC1 gene, and used gene editing to demonstrate the functional importance of this variant in terms of ODC1 levels and growth of neuroblastoma cells. We showed that this variant impacts the ability of MYCN to regulate ODC1, and that it also influences outcome in neuroblastoma, with the rarer variant associated with a better survival. This study addresses the important topic of genetic polymorphisms in cancer.

Abstract

Ornithine decarboxylase (ODC1), a critical regulatory enzyme in polyamine biosynthesis, is a direct transcriptional target of MYCN, amplification of which is a powerful marker of aggressive neuroblastoma. A single nucleotide polymorphism (SNP), G316A, within the first intron of ODC1, results in genotypes wildtype GG, and variants AG/AA. CRISPR-cas9 technology was used to investigate the effects of AG clones from wildtype MYCN-amplified SK-N-BE(2)-C cells and the effect of the SNP on MYCN binding, and promoter activity was investigated using EMSA and luciferase assays. AG clones exhibited decreased ODC1 expression, growth rates, and histone acetylation and increased sensitivity to ODC1 inhibition. MYCN was a stronger transcriptional regulator of the ODC1 promoter containing the G allele, and preferentially bound the G allele over the A. Two neuroblastoma cohorts were used to investigate the clinical impact of the SNP. In the study cohort, the minor AA genotype was associated with improved survival, while poor prognosis was associated with the GG genotype and AG/GG genotypes in MYCN-amplified and non-amplified patients, respectively. These effects were lost in the GWAS cohort. We have demonstrated that the ODC1 G316A polymorphism has functional significance in neuroblastoma and is subject to allele-specific regulation by the MYCN oncoprotein.

Intratumoral Copper Modulates PD-L1 Expression and Influences Tumor Immune Evasion

Therapeutic checkpoint antibodies blocking programmed death receptor 1/programmed death ligand 1 (PD-L1) signaling have radically improved clinical outcomes in cancer. However, the regulation of PD-L1 expression on tumor cells is still poorly understood. Here we show that intratumoral copper levels influence PD-L1 expression in cancer cells. Deep analysis of the The Cancer Genome Atlas database and tissue microarrays showed strong correlation between the major copper influx transporter copper transporter 1 (CTR-1) and PD-L1 expression across many cancers but not in corresponding normal tissues. Copper supplementation enhanced PD-L1 expression at mRNA and protein levels in cancer cells and RNA sequencing revealed that copper regulates key signaling pathways mediating PD-L1-driven cancer immune evasion. Conversely, copper chelators inhibited phosphorylation of STAT3 and EGFR and promoted ubiquitin-mediated degradation of PD-L1. Copper-chelating drugs also significantly increased the number of tumor-infiltrating CD8⁺ T and natural killer cells, slowed tumor growth, and improved mouse survival. Overall, this study reveals an important role for copper in regulating PD-L1 and suggests that anticancer immunotherapy might be enhanced by pharmacologically reducing intratumor copper levels. SIGNIFICANCE: These findings characterize the role of copper in modulating PD-L1 expression and contributing to cancer immune evasion, highlighting the potential for repurposing copper chelators as enhancers of antitumor immunity. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/19/4129/F1.large.jpg.

Interplay between MycN and c-Myc regulates radioresistance and cancer stem cell phenotype in neuroblastoma upon glutamine deprivation

Targeting glutamine metabolism has emerged as a potential therapeutic strategy for Myc overexpressing cancer cells. Myc proteins contribute to an aggressive neuroblastoma phenotype. Radiotherapy is one of the treatment modalities for high-risk neuroblastoma patients. Herein, we investigated the effect of glutamine deprivation in combination with irradiation in neuroblastoma cells representative of high-risk disease and studied the role of Myc member interplay in regulating neuroblastoma cell radioresistance. Methods: Cell proliferation and viability assays were used to establish the effect of glutamine deprivation in neuroblastoma cells expressing c-Myc or MycN. Gene silencing and overexpression were used to modulate the expression of Myc genes to determine their role in neuroblastoma radioresistance. qPCR and western blot investigated interplay between expression of Myc members. The impact of glutamine deprivation on cell response following irradiation was explored using a radiobiological 3D colony assay. DNA repair gene pathways as well as CSC-related genes were studied by qPCR array. Reactive Oxygen Species (ROS) and glutathione (GSH) levels were detected by fluorescence and luminescence probes respectively. Cancer-stem cell (CSC) properties were investigated by sphere-forming assay and flow cytometry to quantify CSC markers. Expression of DNA repair genes and CSC-related genes was analysed by mining publicly available patient datasets. Results: Our results showed that glutamine deprivation decreased neuroblastoma cell proliferation and viability and modulated Myc member expression. We then demonstrated for the first time that combined glutamine deprivation with irradiation led to a selective radioresistance of MYCN-amplified neuroblastoma cells. By exploring the underlying mechanism of neuroblastoma radioresistance properties, our results highlight interplay between c-Myc and MycN expression suggesting compensatory mechanisms in Myc proteins leading to radioresistance in MYCN-amplified cells. This result was associated with the ability of MYCN-amplified cells to dysregulate the DNA repair gene pathway, maintain GSH and ROS levels and to increase the CSC-like population and properties. Conversely, glutamine deprivation led to radiosensitization in non-MYCN amplified cell lines through a disruption of the cell redox balance and a trend to decrease in the CSC-like populations. Mining publicly available gene expression dataset obtained from pediatric neuroblastoma patients, we identified a correlation pattern between Myc members and CSC-related genes as well as a specific group of DNA repair gene pathways. Conclusions: This study demonstrated that MycN and c-Myc tightly cooperate in regulation of the neuroblastoma CSC phenotypes and radioresistance upon glutamine deprivation. Pharmacologically, strategies targeting glutamine metabolism may prove beneficial in Myc-driven tumors. Consideration of MycN/c-Myc status in selecting neuroblastoma patients for glutamine metabolism treatment will be important to avoid potential radioresistance.

ABCC4/MRP4 contributes to the aggressiveness of Myc-associated epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is a complex disease comprising discrete histological and molecular subtypes, for which survival rates remain unacceptably low. Tailored approaches for this deadly heterogeneous disease are urgently needed. Efflux pumps belonging to the ATP-binding cassette (ABC) family of transporters are known for roles in both drug resistance and cancer biology and are also highly targetable. Here we have investigated the association of ABCC4/MRP4 expression to clinical outcome and its biological function in endometrioid and serous tumors, common histological subtypes of EOC. We found high expression of ABCC4/MRP4, previously shown to be directly regulated by c-Myc/N-Myc, was associated with poor prognosis in endometrioid EOC (P = .001) as well as in a subset of serous EOC with a "high-MYCN" profile (C5/proliferative; P = .019). Transient siRNA-mediated suppression of MRP4 in EOC cells led to reduced growth, migration and invasion, with the effects being most pronounced in endometrioid and C5-like serous cells compared to non-C5 serous EOC cells. Sustained knockdown of MRP4 also sensitized endometrioid cells to MRP4 substrate drugs. Furthermore, suppression of MRP4 decreased the growth of patient-derived EOC cells in vivo. Together, our findings provide the first evidence that MRP4 plays an important role in the biology of Myc-associated ovarian tumors and highlight this transporter as a potential therapeutic target for EOC.

Functionalized Carbon Nanostructures Versus Drug Resistance: Promising Scenarios in Cancer Treatment

Carbon nanostructures (CN) are emerging valuable materials for the assembly of highly engineered multifunctional nanovehicles for cancer therapy, in particular for counteracting the insurgence of multi-drug resistance (MDR). In this regard, carbon nanotubes (CNT), graphene oxide (GO), and fullerenes (F) have been proposed as promising materials due to their superior physical, chemical, and biological features. The possibility to easily modify their surface, conferring tailored properties, allows different CN derivatives to be synthesized. Although many studies have explored this topic, a comprehensive review evaluating the beneficial use of functionalized CNT vs G or F is still missing. Within this paper, the most relevant examples of CN-based nanosystems proposed for MDR reversal are reviewed, taking into consideration the functionalization routes, as well as the biological mechanisms involved and the possible toxicity concerns. The main aim is to understand which functional CN represents the most promising strategy to be further investigated for overcoming MDR in cancer.

Inhibition of polyamine synthesis and uptake reduces tumor progression and prolongs survival in mouse models of neuroblastoma

Amplification of the MYCN oncogene is associated with an aggressive phenotype and poor outcome in childhood neuroblastoma. Polyamines are highly regulated essential cations that are frequently elevated in cancer cells, and the rate-limiting enzyme in polyamine synthesis, ornithine decarboxylase 1 (ODC1), is a direct transcriptional target of MYCN. Treatment of neuroblastoma cells with the ODC1 inhibitor difluoromethylornithine (DFMO), although a promising therapeutic strategy, is only partially effective at impeding neuroblastoma cell growth due to activation of compensatory mechanisms resulting in increased polyamine uptake from the surrounding microenvironment. In this study, we identified solute carrier family 3 member 2 (SLC3A2) as the key transporter involved in polyamine uptake in neuroblastoma. Knockdown of SLC3A2 in neuroblastoma cells reduced the uptake of the radiolabeled polyamine spermidine, and DFMO treatment increased SLC3A2 protein. In addition, MYCN directly increased polyamine synthesis and promoted neuroblastoma cell proliferation by regulating SLC3A2 and other regulatory components of the polyamine pathway. Inhibiting polyamine uptake with the small-molecule drug AMXT 1501, in combination with DFMO, prevented or delayed tumor development in neuroblastoma-prone mice and extended survival in rodent models of established tumors. Our findings suggest that combining AMXT 1501 and DFMO with standard chemotherapy might be an effective strategy for treating neuroblastoma.

Targeting Functional Activity of AKT Has Efficacy against Aggressive Neuroblastoma

MYCN-amplified neuroblastoma is one of the deadliest forms of childhood cancer and remains a significant clinical challenge. Direct pharmacological inhibition of MYCN is not currently achievable. One strategy could be to target the AKT/GSK3β pathway, which directly regulates the stability of the MYCN protein. Numerous potent and isoform-specific small-molecule AKT inhibitors have been developed. However, the selection of the right drug combinations in the relevant indication will have a significant impact on AKT inhibitor clinical success. To maximally exploit the potential of AKT inhibitors, a better understanding of AKT isoform functions in cancer is crucial. Here using RNAi to downregulate specific AKT isoforms, we demonstrated that loss of total AKT activity rather than isoform-specific expression was necessary to decrease MYCN expression and cause a significant decrease in neuroblastoma cell proliferation. Consistent with these observations, isoform-specific pharmacological inhibition of AKT was substantially less effective than pan-AKT inhibition in combination with cytotoxic drugs in MYCN-amplified neuroblastoma. The allosteric pan-AKT inhibitor perifosine had promising in vitro and in vivo activity in combination with conventional cytotoxic drugs in MYCN-amplified neuroblastoma cells. Our results demonstrated that perifosine drug combination was able to induce apoptosis and downregulate ABC transporter expression. Collectively, this study shows that selecting pan-AKT inhibitors rather than isoform-specific drugs to synergize with first-line chemotherapy treatment should be considered for clinical trials for aggressive neuroblastoma and, potentially, other MYCN -driven cancers.

LTA1 is a safe, intranasal enterotoxin-based adjuvant that improves vaccine protection against influenza in young, old and B-cell-depleted (μMT) mice

Enterotoxin-based adjuvants including cholera toxin and heat-labile toxin (LT) are powerful manipulators of mucosal immunity; however, past clinical trials identified unacceptable neurological toxicity when LT or mutant AB5 adjuvant proteins were added to intranasal vaccines. Here, we examined the isolated enzymatic A1 domain of LT (LTA1) for intranasal safety and efficacy in combination with influenza (flu) vaccination. LTA1-treated mice exhibited no neurotoxicity, as measured by olfactory system testing and H&E staining of nasal tissue in contrast with cholera toxin. In vaccination studies, intranasal LTA1 enhanced immune responses to inactivated virus antigen and subsequent protection against H1N1 flu challenge in mice (8-week or 24-months). In addition, lung H1N1 viral titers post-challenge correlated to serum antibody responses; however, enhanced protection was also observed in μMT mice lacking B-cells while activation and recruitment of CD4 T-cells into the lung was apparent. Thus, we report that LTA1 protein is a novel, safe and effective enterotoxin adjuvant that improves protection of an intranasal flu vaccination by a mechanism that does not appear to require B-cells.

Combining Carbon Nanotubes and Chitosan for the Vectorization of Methotrexate to Lung Cancer Cells

A hybrid system composed of multi-walled carbon nanotubes coated with chitosan was proposed as a pH-responsive carrier for the vectorization of methotrexate to lung cancer. The effective coating of the carbon nanostructure by chitosan, quantified (20% by weight) by thermogravimetric analysis, was assessed by combined scanning and transmission electron microscopy, and X-ray photoelectron spectroscopy (N1s signal), respectively. Furthermore, Raman spectroscopy was used to characterize the interaction between polysaccharide and carbon counterparts. Methotrexate was physically loaded onto the nanohybrid and the release profiles showed a pH-responsive behavior with higher and faster release in acidic (pH 5.0) vs. neutral (pH 7.4) environments. Empty nanoparticles were found to be highly biocompatible in either healthy (MRC-5) or cancerous (H1299) cells, with the nanocarrier being effective in reducing the drug toxicity on MRC-5 while enhancing the anticancer activity on H1299.

Abstract 3435: Targeting AKT activity inhibits MYCN and sensitizes neuroblastoma to chemotherapeutic agents

MYCN-amplified neuroblastoma is one of the deadliest forms of childhood cancer and remains a significant clinical problem. Direct pharmacological inhibition of MYCN protein is challenging and one possible strategy to treat MYCN-amplified neuroblastoma patients is antagonizing proteins involved in its regulation. The AKT/GSK3β pathway directly regulates stabilization of MYCN, providing a therapeutic rational in MYCN-amplified neuroblastoma. In this study, we addressed the question of how AKT can play a pivotal role in MYCN-amplified neuroblastoma and whether small molecule AKT inhibitors can be promising anti-cancer compounds in children diagnosed from this cancer.

Bioinformatics analysis revealed that high gene expression of AKT1 and AKT2, but not AKT3 was correlated with MYCN amplification and was significantly associated with poor outcome in neuroblastoma patients. Using RNAi-mediated depletion of AKT isoforms or pharmacological inhibition, we then demonstrated that the total AKT activity inhibition rather than the expression of particular isoforms was necessary to cause a significant decrease in neuroblastoma cell proliferation. Our results showed that AKT activity inhibition led to a significant downregulation of MYCN expression through GSK3β regulation. These results demonstrated the potential of targeting AKT activity in MYCN-amplified neuroblastoma patients. Our in vitro and in vivo data revealed promising efficacy for the pan-AKT inhibitor perifosine combined with conventional cytotoxic drugs in MYCN-amplified neuroblastoma cell. Importantly, by genetically modulating MYCN expression (siRNA or plasmid vector), our results demonstrated that MYCN expression is required for perifosine chemosensitisation. This effect was linked to the combined actions of apoptosis activation and the downregulation of ABC transporter expressions.

Collectively, our data strongly support that combining the pan-AKT inhibitor perifosine, which is currently in clinical trial, with clinically-approved drugs for neuroblastoma patients could be a novel therapeutic strategy to indirectly target MYCN in neuroblastoma.

Citation Format: Marion Le Grand, Kathleen Kimpton, Christine Gana, Emanuele Valli, Chelsea Mayoh, Maria Kavallaris. Targeting AKT activity inhibits MYCN and sensitizes neuroblastoma to chemotherapeutic agents [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3435.

Magnetic Graphene Oxide Nanocarrier for Targeted Delivery of Cisplatin: A Perspective for Glioblastoma Treatment

Selective vectorization of Cisplatin (CisPt) to Glioblastoma U87 cells was exploited by the fabrication of a hybrid nanocarrier composed of magnetic γ-Fe2O3 nanoparticles and nanographene oxide (NGO). The magnetic component, obtained by annealing magnetite Fe3O4 and characterized by XRD measurements, was combined with NGO sheets prepared via a modified Hummer's method. The morphological and thermogravimetric analysis proved the effective binding of γ-Fe2O3 nanoparticles onto NGO layers. The magnetization measured under magnetic fields up to 7 Tesla at room temperature revealed superparamagnetic-like behavior with a maximum value of MS = 15 emu/g and coercivity HC ≈ 0 Oe within experimental error. The nanohybrid was found to possess high affinity towards CisPt, and a rather slow fractional release profile of 80% after 250 h. Negligible toxicity was observed for empty nanoparticles, while the retainment of CisPt anticancer activity upon loading into the carrier was observed, together with the possibility to spatially control the drug delivery at a target site.

Combining antioxidant hydrogels with self-assembled microparticles for multifunctional wound dressings

A multi-functional composite to be employed as a dressing material was prepared by combining hydrogel and microparticle systems.

MYCN promotes neuroblastoma malignancy by establishing a regulatory circuit with transcription factor AP4

Amplification of the MYCN oncogene, a member of the MYC family of transcriptional regulators, is one of the most powerful prognostic markers identified for poor outcome in neuroblastoma, the most common extracranial solid cancer in childhood. While MYCN has been established as a key driver of malignancy in neuroblastoma, the underlying molecular mechanisms are poorly understood. Transcription factor activating enhancer binding protein-4 (TFAP4) has been reported to be a direct transcriptional target of MYC. We show for the first time that high expression of TFAP4 in primary neuroblastoma patients is associated with poor clinical outcome. siRNA-mediated suppression of TFAP4 in MYCN-expressing neuroblastoma cells led to inhibition of cell proliferation and migration. Chromatin immunoprecipitation assay demonstrated that TFAP4 expression is positively regulated by MYCN. Microarray analysis identified genes regulated by both MYCN and TFAP4 in neuroblastoma cells, including Phosphoribosyl-pyrophosphate synthetase-2 (PRPS2) and Syndecan-1 (SDC1), which are involved in cancer cell proliferation and metastasis. Overall this study suggests a regulatory circuit in which MYCN by elevating TFAP4 expression, cooperates with it to control a specific set of genes involved in tumor progression. These findings highlight the existence of a MYCN-TFAP4 axis in MYCN-driven neuroblastoma as well as identifying potential therapeutic targets for aggressive forms of this disease.

Suppression of the ATP-binding cassette transporter ABCC4 impairs neuroblastoma tumour growth and sensitises to irinotecan in vivo

The ATP-binding cassette transporter ABCC4 (multidrug resistance protein 4, MRP4) mRNA level is a strong predictor of poor clinical outcome in neuroblastoma which may relate to its export of endogenous signalling molecules and chemotherapeutic agents. We sought to determine whether ABCC4 contributes to development, growth and drug response in neuroblastoma in vivo. In neuroblastoma patients, high ABCC4 protein levels were associated with reduced overall survival. Inducible knockdown of ABCC4 strongly inhibited the growth of human neuroblastoma cells in vitro and impaired the growth of neuroblastoma xenografts. Loss of Abcc4 in the Th-MYCN transgenic neuroblastoma mouse model did not impact tumour formation; however, Abcc4-null neuroblastomas were strongly sensitised to the ABCC4 substrate drug irinotecan. Our findings demonstrate a role for ABCC4 in neuroblastoma cell proliferation and chemoresistance and provide rationale for a strategy where inhibition of ABCC4 should both attenuate the growth of neuroblastoma and sensitise tumours to ABCC4 chemotherapeutic substrates.

HDAC4: a key factor underlying brain developmental alterations in CDKL5 disorder

Cyclin-dependent kinase-like 5 (CDKL5) is a Ser/Thr protein kinase predominantly expressed in the brain. Mutations of the CDKL5 gene lead to CDKL5 disorder, a neurodevelopmental pathology that shares several features with Rett Syndrome and is characterized by severe intellectual disability. The phosphorylation targets of CDKL5 are largely unknown, which hampers the discovery of therapeutic strategies for improving the neurological phenotype due to CDKL5 mutations. Here, we show that the histone deacetylase 4 (HDAC4) is a direct phosphorylation target of CDKL5 and that CDKL5-dependent phosphorylation promotes HDAC4 cytoplasmic retention. Nuclear HDAC4 binds to chromatin as well as to MEF2A transcription factor, leading to histone deacetylation and altered neuronal gene expression. By using a Cdkl5 knockout (Cdkl5 -/Y) mouse model, we found that hypophosphorylated HDAC4 translocates to the nucleus of neural precursor cells, thereby reducing histone 3 acetylation. This effect was reverted by re-expression of CDKL5 or by inhibition of HDAC4 activity through the HDAC4 inhibitor LMK235. In Cdkl5 -/Y mice treated with LMK235, defective survival and maturation of neuronal precursor cells and hippocampus-dependent memory were fully normalized. These results demonstrate a critical role of HDAC4 in the neurodevelopmental alterations due to CDKL5 mutations and suggest the possibility of HDAC4-targeted pharmacological interventions.

The thyroid status reprograms T cell lymphoma growth and modulates immune cell frequencies

In spite of considerable evidence on the regulation of immunity by thyroid hormones, the impact of the thyroid status in tumor immunity is poorly understood. Here, we evaluated the antitumor immune responses evoked in mice with different thyroid status (euthyroid, hyperthyroid, and hypothyroid) that developed solid tumors or metastases after inoculation of syngeneic T lymphoma cells. Hyperthyroid mice showed increased tumor growth along with increased expression of cell cycle regulators compared to hypothyroid and control tumor-bearing mice. However, hypothyroid mice showed a higher frequency of metastases than the other groups. Hyperthyroid mice bearing tumors displayed a lower number of tumor-infiltrating T lymphocytes, lower percentage of functional IFN-γ-producing CD8(+) T cells, and higher percentage of CD19(+) B cells than euthyroid tumor-bearing mice. However, no differences were found in the distribution of lymphocyte subpopulations in tumor-draining lymph nodes (TDLNs) or spleens among different experimental groups. Interestingly, hypothyroid TDLN showed an increased percentage of regulatory T (Treg) cells, while hyperthyroid mice displayed increased number and activity of splenic NK cells, which frequency declined in spleens from hypothyroid mice. Moreover, a decreased number of splenic myeloid-derived suppressor cells (MDSCs) were found in tumor-bearing hyperthyroid mice as compared to hypothyroid or euthyroid mice. Additionally, hyperthyroid mice showed increased cytotoxic activity, which declined in hypothyroid mice. Thus, low levels of intratumoral cytotoxic activity would favor tumor local growth in hyperthyroid mice, while regional and systemic antitumor response may contribute to tumor dissemination in hypothyroid animals. Our results highlight the importance of monitoring the thyroid status in patients with T cell lymphomas.

KEY MESSAGES

T cell lymphoma phenotype is paradoxically influenced by thyroid status. Hyperthyroidism favors tumor growth and hypothyroidism rises tumor dissemination. Thyroid status affects the distribution of immune cell types in the tumor milieu. Thyroid status also modifies the nature of local and systemic immune responses.

Thyroid status modulates T lymphoma growth via cell cycle regulatory proteins and angiogenesis

We have shown in vitro that thyroid hormones (THs) regulate the balance between proliferation and apoptosis of T lymphoma cells. The effects of THs on tumor development have been studied, but the results are still controversial. Herein, we show the modulatory action of thyroid status on the in vivo growth of T lymphoma cells. For this purpose, euthyroid, hypothyroid, and hyperthyroid mice received inoculations of EL4 cells to allow the development of solid tumors. Tumors in the hyperthyroid animals exhibited a higher growth rate, as evidenced by the early appearance of palpable solid tumors and the increased tumor volume. These results are consistent with the rate of cell division determined by staining tumor cells with carboxyfluorescein succinimidyl ester. Additionally, hyperthyroid mice exhibited reduced survival. Hypothyroid mice did not differ significantly from the euthyroid controls with respect to these parameters. Additionally, only tumors from hyperthyroid animals had increased expression levels of proliferating cell nuclear antigen and active caspase 3. Differential expression of cell cycle regulatory proteins was also observed. The levels of cyclins D1 and D3 were augmented in the tumors of the hyperthyroid animals, whereas the cell cycle inhibitors p16/INK4A (CDKN2A) and p27/Kip1 (CDKN1B) and the tumor suppressor p53 (TRP53) were increased in hypothyroid mice. Intratumoral and peritumoral vasculogenesis was increased only in hyperthyroid mice. Therefore, we propose that the thyroid status modulates the in vivo growth of EL4 T lymphoma through the regulation of cyclin, cyclin-dependent kinase inhibitor, and tumor suppressor gene expression, as well as the stimulation of angiogenesis.

Induction of apoptosis in T lymphoma cells by long-term treatment with thyroxine involves PKCζ nitration by nitric oxide synthase

Thyroid hormones are important regulators of cell physiology, inducing cell proliferation, differentiation or apoptosis, depending on the cell type. Thyroid hormones induce proliferation in short-term T lymphocyte cultures. In this study, we assessed the effect of long-term thyroxine (T4) treatment on the balance of proliferation and apoptosis and the intermediate participants in T lymphoma cells. Treatment with T4 affected this balance from the fifth day of culture, inhibiting proliferation in a time-dependent manner. This effect was associated with apoptosis induction, as characterized through nuclear morphological changes, DNA fragmentation, and Annexin V-FITC/Propidium Iodide co-staining. In addition, increased iNOS gene and protein levels, and enzyme activity were observed. The generation of reactive oxygen species, depolarization of the mitochondrial membrane, and a reduction in glutathione levels were also observed. The imbalance between oxidants and antioxidants species is typically associated with the nitration of proteins, including PKCζ, an isoenzyme essential for lymphoma cell division and survival. Consistently, evidence of PKCζ nitration via proteasome degradation was also observed in this study. Taken together, these results suggest that the long-term culture of T lymphoma cells with T4 induces apoptosis through the increased production of oxidative species resulting from both augmented iNOS activity and the loss of mitochondrial function. These species induce the nitration of proteins involved in cell viability, promoting proteasome degradation. Furthermore, we discuss the impact of these results on the modulation of T lymphoma growth and the thyroid status in vivo.

The amyloid precursor protein (APP) triplicated gene impairs neuronal precursor differentiation and neurite development through two different domains in the Ts65Dn mouse model for Down syndrome

Intellectual disability in Down syndrome (DS) appears to be related to severe proliferation impairment during brain development. Recent evidence shows that it is not only cellular proliferation that is heavily compromised in DS, but also cell fate specification and dendritic maturation. The amyloid precursor protein (APP), a gene that is triplicated in DS, plays a key role in normal brain development by influencing neural precursor cell proliferation, cell fate specification, and neuronal maturation. APP influences these processes via two separate domains, the APP intracellular domain (AICD) and the soluble secreted APP. We recently found that the proliferation impairment of neuronal precursors (NPCs) from the Ts65Dn mouse model for DS was caused by derangement of the Shh pathway due to overexpression of patched1(Ptch1), its inhibitory regulator. Ptch1 overexpression was related to increased levels within the APP/AICD system. The overall goal of this study was to determine whether APP contributes to neurogenesis impairment in DS by influencing in addition to proliferation, cell fate specification, and neurite development. We found that normalization of APP expression restored the reduced neuronogenesis, the increased astrogliogenesis, and the reduced neurite length of trisomic NPCs, indicating that APP overexpression underpins all aspects of neurogenesis impairment. Moreover, we found that two different domains of APP impair neuronal differentiation and maturation in trisomic NPCs. The APP/AICD system regulates neuronogenesis and neurite length through the Shh pathway, whereas the APP/secreted AP system promotes astrogliogenesis through an IL-6-associated signaling cascade. These results provide novel insight into the mechanisms underlying brain development alterations in DS.

MYCN-mediated transcriptional repression in neuroblastoma: the other side of the coin

Neuroblastoma is the most common extra cranial solid tumor in childhood and the most frequently diagnosed neoplasm during the infancy. MYCN amplification and overexpression occur in about 25% of total neuroblastoma cases and this percentage increases at 30% in advanced stage neuroblastoma. So far, MYCN expression profile is still one of the most robust and significant prognostic markers for neuroblastoma outcome. MYCN is a transcription factor that belongs to the family of MYC oncoproteins, comprising c-MYC and MYCL genes. Deregulation of MYC oncoprotein expression is a crucial event involved in the occurrence of different types of malignant tumors. MYCN, as well as c-MYC, can heterodimerize with its partner MAX and activate the transcription of several target genes containing E-Box sites in their promoter regions. However, recent several lines of evidence have revealed that MYCN can repress at least as many genes as it activates, thus proposing a novel function of this protein in neuroblastoma biology. Whereas the mechanism by which MYCN can act as a transcriptional activator is relatively well known, very few studies has been done in the attempt to explain how MYCN can exert its transcription repression function. Here, we will review current knowledge about the mechanism of MYCN-mediated transcriptional repression and will emphasize its role as a repressor in the recruitment of a precise set of proteins to form complexes capable of down-regulating specific subsets of genes whose function is actively involved in apoptosis, cell differentiation, chemosensitivity, and cell motility. The finding that MYCN can also act as a repressor has widen our view on its role in oncogenesis and has posed the bases to search for novel therapeutic drugs that can specifically target its transcriptional repression function.

Physical interaction between MYCN oncogene and polycomb repressive complex 2 (PRC2) in neuroblastoma: functional and therapeutic implications

CLU (clusterin) is a tumor suppressor gene that we have previously shown to be negatively modulated by the MYCN proto-oncogene, but the mechanism of repression was unclear. Here, we show that MYCN inhibits the expression of CLU by direct interaction with the non-canonical E box sequence CACGCG in the 5'-flanking region. Binding of MYCN to the CLU gene induces bivalent epigenetic marks and recruitment of repressive proteins such as histone deacetylases and Polycomb members. MYCN physically binds in vitro and in vivo to EZH2, a component of the Polycomb repressive complex 2, required to repress CLU. Notably, EZH2 interacts with the Myc box domain 3, a segment of MYC known to be essential for its transforming effects. The expression of CLU can be restored in MYCN-amplified cells by epigenetic drugs with therapeutic results. Importantly, the anticancer effects of the drugs are ablated if CLU expression is blunted by RNA interference. Our study implies that MYC tumorigenesis can be effectively antagonized by epigenetic drugs that interfere with the recruitment of chromatin modifiers at repressive E boxes of tumor suppressor genes such as CLU.

The DMD locus harbours multiple long non-coding RNAs which orchestrate and control transcription of muscle dystrophin mRNA isoforms

The 2.2 Mb long dystrophin (DMD) gene, the largest gene in the human genome, corresponds to roughly 0.1% of the entire human DNA sequence. Mutations in this gene cause Duchenne muscular dystrophy and other milder X-linked, recessive dystrophinopathies. Using a custom-made tiling array, specifically designed for the DMD locus, we identified a variety of novel long non-coding RNAs (lncRNAs), both sense and antisense oriented, whose expression profiles mirror that of DMD gene. Importantly, these transcripts are intronic in origin and specifically localized to the nucleus and are transcribed contextually with dystrophin isoforms or primed by MyoD-induced myogenic differentiation. Furthermore, their forced ectopic expression in both human muscle and neuronal cells causes a specific and negative regulation of endogenous dystrophin full length isoforms and significantly down-regulate the activity of a luciferase reporter construct carrying the minimal promoter regions of the muscle dystrophin isoform. Consistent with this apparently repressive role, we found that, in muscle samples of dystrophinopathic female carriers, lncRNAs expression levels inversely correlate with those of muscle full length DMD isoforms. Overall these findings unveil an unprecedented complexity of the transcriptional pattern of the DMD locus and reveal that DMD lncRNAs may contribute to the orchestration and homeostasis of the muscle dystrophin expression pattern by either selective targeting and down-modulating the dystrophin promoter transcriptional activity.

CDKL5, a novel MYCN-repressed gene, blocks cell cycle and promotes differentiation of neuronal cells

Mutations in the CDKL5 (cyclin-dependent kinase-like 5) gene are associated with a severe epileptic encephalopathy (early infantile epileptic encephalopathy type 2, EIEE2) characterized by early-onset intractable seizures, infantile spasms, severe developmental delay, intellectual disability, and Rett syndrome (RTT)-like features. Despite the clear involvement of CDKL5 mutations in intellectual disability, the function of this protein during brain development and the molecular mechanisms involved in its regulation are still unknown. Using human neuroblastoma cells as a model system we found that an increase in CDKL5 expression caused an arrest of the cell cycle in the G₀/G₁ phases and induced cellular differentiation. Interestingly, CDKL5 expression was inhibited by MYCN, a transcription factor that promotes cell proliferation during brain development and plays a relevant role in neuroblastoma biology. Through a combination of different and complementary molecular and cellular approaches we could show that MYCN acts as a direct repressor of the CDKL5 promoter. Overall our findings unveil a functional axis between MYCN and CDKL5 governing both neuron proliferation rate and differentiation. The fact that CDKL5 is involved in the control of both neuron proliferation and differentiation may help understand the early appearance of neurological symptoms in patients with mutations in CDKL5.

IKAROS deletions dictate a unique gene expression signature in patients with adult B-cell acute lymphoblastic leukemia

BACKGROUND

Deletions of IKAROS (IKZF1) frequently occur in B-cell precursor acute lymphoblastic leukemia (B-ALL) but the mechanisms by which they influence pathogenesis are unclear. To address this issue, a cohort of 144 adult B-ALL patients (106 BCR-ABL1-positive and 38 B-ALL negative for known molecular rearrangements) was screened for IKZF1 deletions by single nucleotide polymorphism (SNP) arrays; a sub-cohort of these patients (44%) was then analyzed for gene expression profiling.

PRINCIPAL FINDINGS

Total or partial deletions of IKZF1 were more frequent in BCR-ABL1-positive than in BCR-ABL1-negative B-ALL cases (75% vs 58%, respectively, p = 0.04). Comparison of the gene expression signatures of patients carrying IKZF1 deletion vs those without showed a unique signature featured by down-regulation of B-cell lineage and DNA repair genes and up-regulation of genes involved in cell cycle, JAK-STAT signalling and stem cell self-renewal. Through chromatin immunoprecipitation and luciferase reporter assays we corroborated these findings both in vivo and in vitro, showing that Ikaros deleted isoforms lacked the ability to directly regulate a large group of the genes in the signature, such as IGLL1, BLK, EBF1, MSH2, BUB3, ETV6, YES1, CDKN1A (p21), CDKN2C (p18) and MCL1.

CONCLUSIONS

Here we identified and validated for the first time molecular pathways specifically controlled by IKZF1, shedding light into IKZF1 role in B-ALL pathogenesis.

Abstract 789: GSTP1 expression is regulated by MycN and is a marker of poor outcome in childhood neuroblastoma

In childhood neuroblastoma, amplification of the transcription factor MycN is associated with poor outcome and a multidrug resistant phenotype. We have previously shown that MycN regulates the expression of several ATP-binding cassette (ABC) transporter genes, and that these genes represent powerful prognostic markers in neuroblastoma (1,2,3). Although these transporters are able to efflux a wide range of cytotoxic drugs, they do not confer resistance to several important cytotoxic agents used to treat neuroblastoma, including cisplatin and cyclophosphamide, hence we explored the prognostic significance and transcriptional regulation of the phase II detoxifying enzyme, glutathione S-transferase P1 (GSTP1). Using quantitative real-time PCR, GSTP1 gene expression was assessed in a retrospective cohort of 51 patients, and subsequently in a cohort of 207 prospectively accrued primary neuroblastomas. These data, and GSTP1 expression data from an independent microarray study of 251 neuroblastoma samples, were correlated with established prognostic indicators and disease outcome. High levels of GSTP1 were associated with decreased event-free and overall survival in all three cohorts. Multivariate analyses, including age at diagnosis, tumor stage and MYCN amplification status, were conducted on the two larger cohorts and demonstrated independent prognostic significance of GSTP1 expression levels. We also explored the regulation of GSTP1 by MycN using chromatin immunoprecipitation (ChIP) and luciferase reporter assays in neuroblastoma cell lines and found that GSTP1 is a direct transcriptional target of MycN. We conclude that N-Myc regulates multiple components of drug metabolism and efflux pathways, including GSTP1 and transporters of the ABC superfamily. The regulation of these key multidrug resistance mechanisms may have particular significance for malignancies with amplification of Myc family genes. 1) J Biol Chem, 285:19532-19543, 2010 2) J Natl Cancer Institute, 103:1236-51, 2011 4) Nat Rev Cancer, 10:147-156, 2010

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 789. doi:1538-7445.AM2012-789

ABCC multidrug transporters in childhood neuroblastoma: clinical and biological effects independent of cytotoxic drug efflux

Background

Although the prognostic value of the ATP-binding cassette, subfamily C (ABCC) transporters in childhood neuroblastoma is usually attributed to their role in cytotoxic drug efflux, certain observations have suggested that these multidrug transporters might contribute to the malignant phenotype independent of cytotoxic drug efflux.

Methods

A v-myc myelocytomatosis viral related oncogene, neuroblastoma derived (MYCN)–driven transgenic mouse neuroblastoma model was crossed with an Abcc1-deficient mouse strain (658 hMYCN^1/−, 205 hMYCN^+/1 mice) or, alternatively, treated with the ABCC1 inhibitor, Reversan (n = 20). ABCC genes were suppressed using short interfering RNA or overexpressed by stable transfection in neuroblastoma cell lines BE(2)-C, SH-EP, and SH-SY5Y, which were then assessed for wound closure ability, clonogenic capacity, morphological differentiation, and cell growth. Real-time quantitative polymerase chain reaction was used to examine the clinical significance of ABCC family gene expression in a large prospectively accrued cohort of patients (n = 209) with primary neuroblastomas. Kaplan–Meier survival analysis and Cox regression were used to test for associations with event-free and overall survival. Except where noted, all statistical tests were two-sided.

Results

Inhibition of ABCC1 statistically significantly inhibited neuroblastoma development in hMYCN transgenic mice (mean age for palpable tumor: treated mice, 47.2 days; control mice, 41.9 days; hazard ratio [HR] = 9.3, 95% confidence interval [CI] = 2.65 to 32; P < .001). Suppression of ABCC1 in vitro inhibited wound closure (P < .001) and clonogenicity (P = .006); suppression of ABCC4 enhanced morphological differentiation (P < .001) and inhibited cell growth (P < .001). Analysis of 209 neuroblastoma patient tumors revealed that, in contrast with ABCC1 and ABCC4, low rather than high ABCC3 expression was associated with reduced event-free survival (HR of recurrence or death = 2.4, 95% CI = 1.4 to 4.2; P = .001), with 23 of 53 patients with low ABCC3 expression experiencing recurrence or death compared with 31 of 155 patients with high ABCC3. Moreover, overexpression of ABCC3 in vitro inhibited neuroblastoma cell migration (P < .001) and clonogenicity (P = .03). The combined expression of ABCC1, ABCC3, and ABCC4 was associated with patients having an adverse event, such that of the 12 patients with the “poor prognosis” expression pattern, 10 experienced recurrence or death (HR of recurrence or death = 12.3, 95% CI = 6 to 27; P < .001).

Conclusion

ABCC transporters can affect neuroblastoma biology independently of their role in chemotherapeutic drug efflux, enhancing their potential as targets for therapeutic intervention.

c-MYC oncoprotein dictates transcriptional profiles of ATP-binding cassette transporter genes in chronic myelogenous leukemia CD34+ hematopoietic progenitor cells

Resistance to chemotherapeutic agents remains one of the major impediments to a successful treatment of chronic myeloid leukemia (CML). Misregulation of the activity of a specific group of ATP-binding cassette transporters (ABC) is responsible for reducing the intracellular concentration of drugs in leukemic cells. Moreover, a consistent body of evidence also suggests that ABC transporters play a role in cancer progression beyond the efflux of cytotoxic drugs. Despite a large number of studies that investigated the function of the ABC transporters, little is known about the transcriptional regulation of the ABC genes. Here, we present data showing that the oncoprotein c-MYC is a direct transcriptional regulator of a large set of ABC transporters in CML. Furthermore, molecular analysis carried out in CD34+ hematopoietic cell precursors of 21 CML patients reveals that the overexpression of ABC transporters driven by c-MYC is a peculiar characteristic of the CD34+ population in CML and was not found either in the population of mononuclear cells from which they had been purified nor in CD34+ cells isolated from healthy donors. Finally, we describe how the methylation state of CpG islands may regulate the access of c-MYC to ABCG2 gene promoter, a well-studied gene associated with multidrug resistance in CML, hence, affecting its expression. Taken together, our findings support a model in which c-MYC-driven transcriptional events, combined with epigenetic mechanisms, direct and regulate the expression of ABC genes with possible implications in tumor malignancy and drug efflux in CML.

SIRT1 promotes N-Myc oncogenesis through a positive feedback loop involving the effects of MKP3 and ERK on N-Myc protein stability

The N-Myc oncoprotein is a critical factor in neuroblastoma tumorigenesis which requires additional mechanisms converting a low-level to a high-level N-Myc expression. N-Myc protein is stabilized when phosphorylated at Serine 62 by phosphorylated ERK protein. Here we describe a novel positive feedback loop whereby N-Myc directly induced the transcription of the class III histone deacetylase SIRT1, which in turn increased N-Myc protein stability. SIRT1 binds to Myc Box I domain of N-Myc protein to form a novel transcriptional repressor complex at gene promoter of mitogen-activated protein kinase phosphatase 3 (MKP3), leading to transcriptional repression of MKP3, ERK protein phosphorylation, N-Myc protein phosphorylation at Serine 62, and N-Myc protein stabilization. Importantly, SIRT1 was up-regulated, MKP3 down-regulated, in pre-cancerous cells, and preventative treatment with the SIRT1 inhibitor Cambinol reduced tumorigenesis in TH-MYCN transgenic mice. Our data demonstrate the important roles of SIRT1 in N-Myc oncogenesis and SIRT1 inhibitors in the prevention and therapy of N-Myc–induced neuroblastoma.

The class III histone deacetylase SIRT1 is repressed by tumor suppressor genes and exerts divergent effects on tumorigenesis depending on its down-stream targets. Small molecule SIRT1 inhibitors have shown promising anti-cancer effects both in vitro and in vivo. Here we identified SIRT1 as a gene directly up-regulated by N-Myc and identified SIRT1-mediated transcriptional repression as a novel mechanism responsible for maintaining N-Myc oncoprotein stability. Moreover, SIRT1 contributed to N-Myc–induced cell proliferation, and preventative treatment with the SIRT1 inhibitor Cambinol reduced tumorigenesis in N-Myc transgenic mice. Our data identify SIRT1 as an important co-factor for N-Myc oncogenesis and provide important evidence for the potential application of SIRT1 inhibitors in the prevention and therapy of N-Myc–induced neuroblastoma.

APP-dependent up-regulation of Ptch1 underlies proliferation impairment of neural precursors in Down syndrome

Mental retardation in Down syndrome (DS) appears to be related to severe neurogenesis impairment during critical phases of brain development. Recent lines of evidence in the cerebellum of a mouse model for DS (the Ts65Dn mouse) have shown a defective responsiveness to Sonic Hedgehog (Shh), a potent mitogen that controls cell division during brain development, suggesting involvement of the Shh pathway in the neurogenesis defects of DS. Based on these premises, we sought to identify the molecular mechanisms underlying derangement of the Shh pathway in neural precursor cells (NPCs) from Ts65Dn mice. By using an in vitro model of NPCs obtained from the subventricular zone and hippocampus, we found that trisomic NPCs had an increased expression of the Shh receptor Patched1 (Ptch1), a membrane protein that suppresses the action of a second receptor, Smoothened (Smo), thereby maintaining the pathway in a repressed state. Partial silencing of Ptch1 expression in trisomic NPCs restored cell proliferation, indicating that proliferation impairment was due to Ptch1 overexpression. The overexpression of Ptch1 in trisomic NPCs resulted from increased levels of AICD [a transcription-promoting fragment of amyloid precursor protein (APP)] and increased AICD binding to the Ptch1 promoter. Our data provide novel evidence that Ptch1 overexpression underlies derangement of the Shh pathway in trisomic NPCs with consequent proliferation impairment. The demonstration that Ptch1 overexpression in trisomic NPCs is due to an APP fragment provides a link between this trisomic gene and the defective neuronal production that characterizes the DS brain.

A SP1/MIZ1/MYCN repression complex recruits HDAC1 at the TRKA and p75NTR promoters and affects neuroblastoma malignancy by inhibiting the cell response to NGF

Neuroblastoma is the most common extracranial solid tumor of childhood. One important factor that predicts a favorable prognosis is the robust expression of the TRKA and p75NTR neurotrophin receptor genes. Interestingly, TRKA and p75NTR expression is often attenuated in aggressive MYCN-amplified tumors, suggesting a causal link between elevated MYCN activity and the transcriptional repression of TRKA and p75NTR, but the precise mechanisms involved are unclear. Here, we show that MYCN acts directly to repress TRKA and p75NTR gene transcription. Specifically, we found that MYCN levels were critical for repression and that MYCN targeted proximal/core promoter regions by forming a repression complex with transcription factors SP1 and MIZ1. When bound to the TRKA and p75NTR promoters, MYCN recruited the histone deacetylase HDAC1 to induce a repressed chromatin state. Forced re-expression of endogenous TRKA and p75NTR with exposure to the HDAC inhibitor TSA sensitized neuroblastoma cells to NGF-mediated apoptosis. By directly connecting MYCN to the repression of TRKA and p75NTR, our findings establish a key pathway of clinical pathogenicity and aggressiveness in neuroblastoma.

Direct and coordinate regulation of ATP-binding cassette transporter genes by Myc factors generates specific transcription signatures that significantly affect the chemoresistance phenotype of cancer cells

Increased expression of specific ATP-binding cassette (ABC) transporters is known to mediate the efflux of chemotherapeutic agents from cancer cells. Therefore, establishing how ABC transporter genes are controlled at their transcription level may help provide insight into the role of these multifaceted transporters in the malignant phenotype. We have investigated ABC transporter gene expression in a large neuroblastoma data set of 251 tumor samples. Clustering analysis demonstrated a strong association between differential ABC gene expression patterns in tumor samples and amplification of the MYCN oncogene, suggesting a correlation with MYCN function. Using expression profiling and chromatin immunoprecipitation studies, we show that MYCN oncoprotein coordinately regulates transcription of specific ABC transporter genes, by acting as either an activator or a repressor. Finally, we extend these notions to c-MYC showing that it can also regulate the same set of ABC transporter genes in other tumor cells through similar dynamics. Overall our findings provide insight into MYC-driven molecular mechanisms that contribute to coordinate transcriptional regulation of a large set of ABC transporter genes, thus affecting global drug efflux.

Hysteroscopic findings in 344 women with recurrent spontaneous abortion

STUDY OBJECTIVE

To evaluate the prevalence of different anatomic factors in women with recurrent spontaneous abortion (RSA).

DESIGN

Retrospective analysis over 9 years (Canadian Task Force classification II-2).

SETTING

University hospital-affiliated endoscopic unit.

PATIENTS

Three hundred forty-four consecutive patients with RSA and 922 controls referred for abnormal uterine bleeding.

INTERVENTION

Diagnostic hysteroscopy.

MEASUREMENTS AND MAIN RESULTS

Major and minor uterine mullerian abnormalities (septate, unicornuate uteri) were found significantly more often in women with RSA than in controls (32% vs 6%, p <0.001). The frequency of acquired uterine anomalies (submucous myomas, polyps) was significantly higher in controls (32% vs 9%, p <0.001). No significant differences were observed between groups in frequency of adhesions (4% vs 2%).

CONCLUSION

Major mullerian uterine abnormalities are associated with RSA, and minor uterine anomalies may be correlated with an increased risk of recurrent miscarriage.

Outpatient diagnostic hysteroscopy

STUDY OBJECTIVE

To evaluate the feasibility, validity, indications, and results of a large series of diagnostic hysteroscopies performed without anesthesia.

DESIGN

Retrospective analysis of hysteroscopy charts performed between 1989 and 1996 (Canadian Task Force classification II-2).

SETTING

University-affiliated endoscopy unit.

PATIENTS

Four thousand consecutive women referred for different indications.

INTERVENTIONS

Diagnostic hysteroscopy was performed in 91% of patients without premedication or anesthetics. In some women premedication or general or local anesthesia was required to access the uterine cavity.

MEASUREMENTS AND MAIN RESULTS

The success rate, validity indication, complication rate, and number of biopsies were critically evaluated and assessed in relation to increased experience of operators. In 91% of women we accessed the uterine cavity at the first attempt without premedication, whereas 207 (5. 1%) patients required local anesthesia and 99 (2.4%) premedication. Only 1.6% required general anesthesia. In 52% intrauterine pathology was diagnosed and in 21% further surgical treatment was suggested.

CONCLUSION

Hysteroscopy was feasible when performed in an outpatient setting without general or local anesthesia in more than 90% of women. The operator's experience seems a key factor both for accurate endometrial evaluation and to reduce failure and endometrial biopsy rates. The low frequency of further surgical treatment justifies performing the procedure in the office.

[The use of electrosurgery in the treatment of extra-cervical genital condylomatosis]

BACKGROUND AND AIMS

The aim of this study was to evaluate the therapeutic efficacy of electrosurgery in the treatment of HPV correlated extra-cervical genital lesions.

METHODS

A group of 78 patients with clinical or colposcopic, histologically ascertained vulvar or perineal condylomatosis were enrolled consecutively between March 1994 and July 1995 at the Cervico-Vaginal and Vulvar Pathology Unit of the Obstetrics and Gynecology Clinic at Tor Vergata University, Rome. All patients underwent physical treatment with a radiofrequency electrosurgical knife using exclusively cutting current. In addition to patient compliance, the following parameters were evaluated: length of surgery and recovery times, collateral effects and possible long-term results; a colposcopic and, if necessary, bioptic follow-up was also performed at 3, 6 and 12 months after treatment.

RESULTS

Seven out of the group of 68 patients with subclinical condylomatosis presented histologically documented recidivation during the course of follow-up. In the discussion the authors evaluate the positive results obtained using this method and, based on the physical principle underlying electroradiosurgery, they suggest using the term electrosurgical vaporisation for destructive electrotherapy using a cutting current, which is suited to the physical mechanism with which this current acts.

Transvaginal sonographic and hysteroscopic findings in postmenopausal women receiving tamoxifen

STUDY OBJECTIVE

To evaluate the effect of tamoxifen on the endometrium.

DESIGN

Prospective study.

SETTING

Department of Obstetrics and Gynecology of the University of Rome.

PATIENTS

One hundred one postmenopausal women with breast cancer receiving tamoxifen 20 to 30 mg/day for at least 1 year; of these 78 were asymptomatic and 23 had vaginal bleeding.

INTERVENTIONS

All patients underwent transvaginal color Doppler sonography. Those with endometrial thickness greater than 5 mm were advised to undergo hysteroscopy and if necessary endometrial biopsy. For women with endometrial thickness less than 5 mm, hysteroscopy was recommended only if irregular endometrial echotexture was observed.

MEASUREMENTS AND MAIN RESULTS

Eleven (14%) asymptomatic patients and 1 (4.3%) with vaginal bleeding had endometrial thickness less than 5 mm (p = 0.4, NS). Women with vaginal bleeding had a significantly thicker endometrium than asymptomatic patients (15.8 +/- 7.5 vs 11.1 +/- 5.7 mm, p = 0.003). In the asymptomatic group 31 polyps, 15 atrophic endometria, and 6 hyperplasias were observed. Two endometrial cancers, 13 polyps, and 3 hyperplasias were detected in patients with vaginal bleeding. Hysteroscopy did not always allow endometrial biopsy, even in the presence of increased endometrial thickness with or without irregular surface. No statistical differences were found for mean pulsatility and resistance indexes of uterine and endometrial arteries between symptomatic and asymptomatic women, but these indexes were significantly lower compared with normal postmenopausal values.

CONCLUSION

Women receiving tamoxifen, especially those who are asymptomatic, should be closely monitored by transvaginal sonography and hysteroscopy to detect endometrial pathologies.

Costs and Benefits of Office Diagnostic Hysteroscopy

In Italy, the main location for performing diagnostic hysteroscopy is the office. The success of office hysteroscopy is related to savings of time and money and the convenience for the physician and patient. We evaluated 4000 diagnostic hysteroscopies performed between January 2, 1989, and March 1, 1996. In 17.8% of these patients we subsequently performed operative hysteroscopies (metroplasty, synechiolysis, myomectomy, polypectomy for polyps >2 cm), and in 5.2% a total abdominal hysterectomy for abnormal uterine bleeding or endometrial cancer. The low percentage of operations underlines the efficacy of office diagnostic hysteroscopy, especially if we evaluate costs and accuracy of this procedure in detecting uterine pathologies.

Hysteroscopically detected asymptomatic müllerian anomalies. Prevalence and reproductive implications

OBJECTIVE

To assess the prevalence of uterine anomalies and relative reproductive function in 322 women with abnormal uterine bleeding (AUB) evaluated by diagnostic hysteroscopy.

STUDY DESIGN

Uterine contours were classified as septate/bicornuate, arcuate or normal on the basis of hysteroscopy. A complete medical history was obtained from all the subjects; it included a questionnaire on menstrual characteristics, reproductive history and pregnancy outcome. Cumulative birth rates, frequency of spontaneous abortion, preterm delivery, malpresentation and mode of delivery in patients with normal and abnormal uteri were compared using life table analysis, the log-rank test and chi 2 analysis.

RESULTS

Arcuate, septate/bicornuate and unicornuate uteri were observed in 6.5%, 3.7% and 0.3% of women, respectively. Although 24-month pregnancy rates and monthly fecundability rates were similar in women with and without müllerian anomalies, the 36-month cumulative live birth rate was significantly lower in women with a septate/bicornuate uterus. Overall, women with uterine malformations showed a significantly higher miscarriage rate (P < .05) and a significantly lower term delivery rate (P < .05) than women with a normal-shaped uterus.

CONCLUSION

Diagnostic hysteroscopy in women with AUB detected a 10% prevalence of uterine anomalies, which were associated with a significantly higher incidence of spontaneous abortion and lower cumulative live birth rates.

A new hysteroscopic classification of and nomenclature for endometrial lesions

STUDY OBJECTIVE

To establish a hysteroscopic classification of endometrial lesions based on a combined score:

DESIGN

A prospective study to grade four features of endometrial lesions (thickness, surface, color, vascularization) and subdivide them as mild (low risk) and severe (high risk).

SETTING

Gynecologic endoscopy unit of an obstetric and gynecology clinic.

PATIENTS

Two hundred twenty-nine women with hysteroscopically diagnosed endometrial lesions.

INTERVENTIONS

Hysteroscopic inspection of endometriotic lesions, with grading performed on the four features.

MEASUREMENTS AND MAIN RESULTS

The sensitivity and specificity of our system were 86.9% and 87.4% for mild pathology, and 96% and 92.9% for severe pathology.

CONCLUSIONS

This hysteroscopic classification of endometrial pathology can be useful for a better definition of endometrial lesions. The method has good sensitivity and specificity.

The use of topical anesthesia in diagnostic hysteroscopy and endometrial biopsy

OBJECTIVE

To show that intrauterine anesthesia is a reliable method for reducing pain associated with endocavitary procedures.

DESIGN

A prospective, randomized, double-blind study.

SETTING

The Department of Obstetrics and Gynecology, Tor Vergata University of Rome, Rome, Italy.

PATIENTS

Forty-five patients undergoing diagnostic hysteroscopy (n = 27) or hysteroscopy and endometrial biopsy (n = 18).

INTERVENTIONS

Five milliliters of 2% mepivacaine or saline solution were injected transcervically into the uterine cavity before performing the procedures.

MAIN OUTCOME MEASURES

Evaluation of pain reduction on a visual analogue scale.

RESULTS

Pain expectation and pain reported were reduced during and after the procedures.

CONCLUSION

Topical anesthesia effectively reduces pain during hysteroscopy and endometrial biopsy.

Hysteroscopic Evaluation in Patients with Thickened Endometrium at Vaginal Ultrasound Examination

The purpose of this study was to evaluate the hysteroscopic appearance of the endometrium in cases with abnormal thickening (>8mm) evaluated by vaginal ultrasound. We considered postmenopausal patients who were asymptomatic and those with abnormal uterine bleeding (AUB). Hysteroscopy with endometrial biopsy revealed cancer, hyperplasia, polyps, and myoma in patients with AUB. In the asymptomatic group with increased endometrial thickening, hysteroscopy revealed hyperplasia, polyps and myoma. Our results show that vaginal ultrasound is a reliable method for evaluation of the endometrium in postmenopausal women. Hysteroscopic examination is required to assess the endometrial pathology, and to determine which patients will require biopsy or surgical intervention.

Hysteroscopic Findings of Placental Site Nodule (PSN). A Case Report

The hysteroscopic findings of placental site nodule, an unusual and cytologically alarming lesion, is reported. A 29-year-old woman, para 2, presented with a 3 month history of intermenstrual bleeding. The last spontaneous delivery occurred 12 months previously. Pelvic examination was negative. Ultrasound examination revealed increased thickness and irregularity of the endometrium (16-18 mm). Diagnostic hysteroscopy performed the same day revealed the endometrial surface to be irregular due to a focal nodular lesion with increased regular vascularization in the fundal area. The nodule was about 2 cm in diameter, had an irregular surface and a variegated appearance, and was white-red in color with hemorrhagic and necrotic areas. A targeted biopsy of the lesion was performed. Histologic examination revealed a "placental site nodule." A subsequent D&C confirmed the diagnosis. Fifteen days after surgery, hPL and hCG serum levels were evaluated and were negative. This is the first hysteroscopic report of a placental site nodule. We conclude that hysteroscopic evaluation of abnormal uterine bleeding is very important, because it allows the examination of the uterine cavity and lesions, making possible a guided biopsy. Hysteroscopy is also useful during the follow-up of this type of pathology.

The use of topical anesthesia in diagnostic hysteroscopy and endometrial biopsy

STUDY OBJECTIVE

To determine whether the pain and discomfort of routine hysteroscopy with endometrial biopsy to diagnose infertility and endometrial pathology can be minimized by topical application of mepivacaine.

DESIGN

Prospective, randomized, double-blind study.

SETTING

The Department of Obstetrics and Gynecology at a teaching hospital in Rome, Italy.

PATIENTS

Eighteen women undergoing diagnostic hysteroscopy.

INTERVENTIONS

Hysteroscopy and endometrial biopsy were performed after transcervical injection of 5 ml 2% mepivacaine or 5 ml saline solution into the uterine cavity.

MEASUREMENTS AND MAIN RESULTS

Difficulty introducing the hysteroscope was rated by the operator on a scale of 1 to 3. An observer scored visible signs of each woman's distress using a three-point scale. The patients reported their pain 15, 30, 60, 120 minutes after the procedure on a visual analog scale. Mepivacaine was more effective than placebo according to all measurements.

CONCLUSIONS

Topical mepivacaine reduced the pain experienced during and after hysteroscopy and endometrial biopsy.