Abstract 2733: KITENIN and ErbB4 contribute to further malignant changes in colorectal cancer through c-Jun/AP-1 activation

KITENIN (KAI1 C-terminal interacting tetraspanin, Vangl1) is not only a major component of PCP pathway but also a functional protein promoting colorectal cancer (CRC) cell motility and invasiveness. Here, we report the mechanism of which KITENIN leads further malignant changes in CRC progression after loss of tumor suppressor Adenomatous polyposis coli (APC). KITENIN increases the level of AP-1 activity through interaction with Dvl2, which is subsequently being degraded. Decreasing Dvl2 via interaction with KITENIN or via treatment of si-RNA to Dvl2 significantly increases the AP-1 activity through elevating the level of c-jun and c-jun phosphorylation. EGF acts upstream of KITENIN/AP-1 signaling and induces synergic AP-1 activation in the presence of elevated KITENIN, which requires the interaction of KITENIN with ErbB4. The morphological characteristics of adenocarcinoma were observed in intestinal tumor tissues from compound villin-KITENIN transgenic/APCmin/+ mice but not from APCmin/+ mice, both of which express the elevated level of ErbB4. This result demonstrates that further malignant phenotype of intestinal tumor can be induced by elevated KITENIN and ErbB4 via promoting c-Jun/AP-1 activation within an APC loss-associated tumor microenvironment. Our present results suggest the possibility of the addition of anti-KITENIN therapy to the use of EGFR inhibitors in the treatment of CRC patients with APC mutation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2733. doi:10.1158/1538-7445.AM2011-2733

Glycoprotein 90K, downregulated in advanced colorectal cancer tissues, interacts with CD9/CD82 and suppresses the Wnt/beta-catenin signal via ISGylation of beta-catenin

BACKGROUND AND AIMS

90K, a tumour-associated glycoprotein, interacts with galectins and has roles in host defence by augmenting the immune response, but the serum 90K level was suggested to indicate poor prognosis in several cancers. The cellular mechanisms of 90K action on colorectal cancer (CRC) cell motility and its effect on CRC progression were investigated.

METHODS

The impact of 90K was analysed by combining cell cultures, in vitro assays, and immunohistochemistry.

RESULTS

Secreted 90K suppresses CRC cell invasion, but this action of 90K is masked through binding with extracellular galectins. A novel pathway is identified comprising a secretory 90K and a CD9/CD82 tetraspanin web; in this pathway, 90K interacts with CD9/CD82, suppresses the Wnt/beta-catenin signal via a novel proteasomal-ubiquitination mechanism of beta-catenin that is dependent on ISG15 (interferon-stimulated gene-15) modification (ISGylation) but not on glycogen synthase kinase 3beta (GSK-3beta) and Siah/Adenomatous polyposis coli (APC). In a syngeneic mouse colon tumour model, tumour growth and lung metastasis were increased with 90K knockdown. In colon tissues from stage IV human CRC and invading cancer cells of corresponding metastatic liver tissues, in which beta-catenin and galectin expression was higher, immunostained 90K and CD9/CD82 were lower than in adjacent hepatic tissues or colon tissues from stage I.

CONCLUSIONS

90K itself has antitumour activity in CRC cells via suppression of Wnt signalling with a novel mechanism of ISGylation-dependent ubiquitination of beta-catenin when it interacts with CD9/CD82, but is downregulated in advanced CRC tissues. The data suggest a strategy of strengthening this novel pathway with concomitant knockdown of galectins as a potential therapeutic approach to CRC progression.

KAI1 COOH-terminal interacting tetraspanin (KITENIN) expression in early and advanced laryngeal cancer

OBJECTIVES/HYPOTHESIS

To investigate the expression of KAI1 COOH-terminal interacting tetraspanin (KITENIN) in patients with laryngeal cancers and to examine the correlation between its expression and various clinical and pathological variables.

STUDY DESIGN

Cross-sectional study with planned data collection.

METHODS

Tumor specimens were collected from 32 patients with laryngeal squamous carcinoma (collection of consecutive 32 tumor samples; 14 early stage, 18 advanced stage). Expression of KITENIN in the tissues obtained was determined by Western blot analysis and immunohistochemical staining. The patient characteristics including age, gender, tumor location, histology, stage, tumor extent, lymph node metastasis, and survival were obtained by review of the hospital records.

RESULTS

KITENIN expression was significantly increased in laryngeal cancer tissues compared to adjacent normal tissue mucosa, as well as in metastatic lymph nodes compared to nonmetastatic lymph nodes. High KITENIN expression was significantly associated with advanced stage, tumor extent, and lymph node metastasis (P = .016, .016, and .005, respectively). There was no difference in the overall survival and disease-free survival between the low- and high-KITENIN expression groups among patients with laryngeal cancer.

CONCLUSIONS

These results suggest that KITENIN expression may be associated with tumor progression in patients with laryngeal cancer. Further studies are needed to determine whether KITENIN expression adds prognostic value to conventional factors, such as the stage and status of metastasis, in a large series with a long period of follow-up.

KITENIN represents a more aggressive phenotype in a murine model of oral cavity squamous carcinoma

Objective: To investigate the tumor invasiveness and early lung metastasis associated with KITENIN in a murine model of oral cavity squamous carcinoma.

Study Design: Cross-sectional study with planned data collection.

Setting: Department of Otolaryngology–Head and Neck Surgery, Medical Research Center for Gene Regulation, and Pathology, Chonnam National University Medical School and Hwasun Hospital.

Subjects and Methods: The cDNA of KITENIN and vector only were transfected into the SCC VII (murine squamous cell line) cells. The suspension of 5 × 105/mL viable KITENIN- or vector-transfected SCC VII cells was injected into the floor of the mouth of C3H/HeJ syngeneic mice, deep into the mylohyoid muscle via the intraoral approach. From the first to the sixth week after injection, tumor, lung, liver, and brain tissues were obtained.

Results: For all groups, the tumor invaded the superficial musculature of the floor of the mouth, the deep musculature of the floor of the mouth, the salivary glands, perineural tissue, bone, and skin, sequentially. Lung metastases developed multiple focal nodular patterns at first and then became more extensive. Earlier and more aggressive tumor invasion into the deep floor of the mouth musculature, salivary glands, perineural tissue, bone, and skin was observed in the KITENIN-transfected group compared to the vector-only group. An earlier and more extensive lung metastasis was observed in the KITENIN group.

Conclusion: An antisense KITENIN strategy might inhibit distant metastasis and the progression of head and neck squamous cell carcinoma.

Intratumoral administration of anti-KITENIN shRNA-loaded PEI-alt-PEG nanoparticles suppressed colon carcinoma established subcutaneously in mice

Biodegradable gene carrier, termed as PEI-alt-PEG, has been synthesized based on Michael addition reaction between lower Mw PEI and poly(ethylene glycol) (PEG) diacrylate and tested its potential of anti-metastatic cancer gene therapy by using anti-KITENIN short hairpin RNA. KITENIN is known to promote invasion of mouse colon adenocarcinoma in vivo. Intratumoral administration of anti-KITENIN shRNA-loaded PEI-alt-PEG nanoparticles has shown suppressed proliferlation and enhanced apoptosis signal in tumor compared to commercial available liposome, leading to delayed tumor growth.

Abstract 1471: Glycoprotein 90K suppresses Wnt signaling via ISGylation-dependent ubiquitination of β-catenin that needs interaction with CD9/CD82

Backgrounds: Previously, we have observed that a tumor-associated 90K glycoprotein plays a potential tumor suppressor role in colorectal cancer (CRC) cells via antagonizing the canonical Wnt signaling pathway, which is functionally masked via interaction with extracellular galectin. Here, we investigated the signaling pathways of 90K action on CRC cells and its expression in human CRC tissues. Results: We identify a novel pathway comprising a secretory 90K and a CD9/CD82 tetraspanin web; in this pathway, 90K interacts with CD9/CD82, suppresses the Wnt/β-catenin signal via a novel proteasomal-ubiquitination mechanism of β-catenin that is dependent of ISG15 modification (ISGylation). In colon tissues from stage IV human CRC and invading cancer cells of corresponding metastatic liver tissues, in which β-catenin and galectin expression was higher, immunostained 90K and CD9/CD82 were lower than in adjacent hepatic tissues or colon tissues from stage I. Conclusions: 90K itself has antitumor activity in CRC cells via suppression of Wnt signaling with a novel mechanism of ISGylation-dependent ubiquitination of β-catenin when it interacts with CD9/CD82, but is downregulated in advanced CRC tissues. Our data suggest a strategy of strengthening this novel pathway with concomitant knockdown of galectins as a potential therapeutic approach to CRC progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1471.

Myasthenia gravis presenting as isolated respiratory failure: a case report

Myasthenia gravis (MG) is often complicated by respiratory failure, known as a myasthenic crisis. However, most of the patients who develop respiratory symptoms do so during the late course of disease and have other neurological signs and symptoms. However, in some patients respiratory failure is the initial presenting symptom. We report the case of a 68-year-old woman with MG who presented with isolated respiratory failure as her first presenting symptom. As illustrated by this case, it is important to consider neuromuscular disorders in cases of unexplained respiratory failure.

Effect of human RAD50 gene therapy on glaucoma filtering surgery in rabbit eye

PURPOSE

To investigate the antiproliferative effects of the subconjunctival injection of human RAD50 (hRAD50) on fibroblasts after glaucoma filtering surgery.

METHODS

After glaucoma filtering surgery in normal rabbit eye, the subconjunctival injection of hRAD50 was performed. Morphologic changes in the subconjunctival area of hRAD50-treated eyes were compared with those of mitomycin C (MMC)-treated and control eyes using light and electron microscopy. Results. Two weeks after hRAD50 treatment (2 microg), the conjunctival epithelium increased in thickness and had many tonofilaments, but the basal lamina was intact. The subconjunctival fibroblasts exhibited a granular endoplasmic reticulum without distension. Most of the collagen bundles and fibers around the fibroblasts disappeared, and apoptotic cells with many fragmented nuclei and condensed chromatin were observed. Four weeks after hRAD50 treatment, the findings were similar with those of 2 weeks except for a slight increase in the number of collagen bundles and fibers and the appearance of macrophages. In MMC-treated eyes, the conjunctival epithelium also increased in thickness and had many tonofilaments. However, intercellular spaces were widened and the basal lamina was interrupted in some areas. Most of the collagen bundles and fibers were shortened, and apoptotic cells were also observed.

CONCLUSIONS

These results demonstrate that the histologic antiproliferative effects of local hRAD50 on the conjunctival fibroblasts are similar to those of MMC, but without damage to the basal lamina of the conjunctival epithelium, and suggest that hRAD50 may be useful as a possible antifibroblastic agent for glaucoma filtering surgery. However, further investigations are needed to test for possible systemic complications, which so far have not been reported.

Experimental Inhibition of Corneal Neovascularization by Photodynamic Therapy with Verteporfin

PURPOSE

To investigate the anti-angiogenic effects of photodynamic therapy with verteporfin in a rabbit model of corneal neovascularization.

METHODS

One week after suturing, the localization of verteporfin in the neovascularized cornea was examined through fluorescent microscopy 1 hr after administration. Rabbits were treated with one or two times of photodynamic therapy with verteporfin at 1-week intervals. Analysis of corneal neovascularization was performed by biomicroscopic and histological examinations.

RESULTS

Fluorescent microscopy showed green fluorescence in the vascular walls and interstitial tissue of the corneal stroma. The mean percentages of neovascularized corneal area at 3 days, 1 week, and 2 weeks after one time of photodynamic therapy were 90.3% +/- 3.5%, 71.6% +/- 6.2%, and 43.6% +/- 15.1% in treated eyes and 96.4% +/- 1.9% (p = 0.10), 88.6% +/- 4.6% (p = 0.01), and 76.8% +/- 4.4% (p < 0.01) in control eyes, respectively. The mean percentages 3 days, 1 week, and 2 weeks after two times of photodynamic therapy were also significantly lower in treated eyes compared with control eyes. In quantitative histological examination at 1 and 2 weeks after therapy, treated eyes showed significantly less neovascular area and number of vessels than control eyes.

CONCLUSIONS

Photodynamic therapy with verteporfin is a safe and useful procedure to reduce experimental corneal neovascularization and can be used to inhibit angiogenesis in the cornea.

KITENIN recruits Dishevelled/PKC delta to form a functional complex and controls the migration and invasiveness of colorectal cancer cells

BACKGROUND AND AIMS

KITENIN was previously reported to promote metastasis in mouse colon tumour models; however, the signalling mechanism of KITENIN at the cellular level was unknown. Here the functional role of KITENIN with respect to colorectal cancer (CRC) cell invasion and its expression in CRC tissues were investigated.

METHODS

The effect of KITENIN on cell motility was analysed in a migration and invasion assay upon its overexpression and knockdown. Immunoprecipitation was used to elucidate binding partners, and immunohistochemistry was used to study expression levels.

RESULTS

KITENIN overexpression enhanced the migration of rat intestinal epithelial cells, whereas a loss of invasiveness was observed in CRC cells after KITENIN knockdown. Mechanically, KITENIN served as a scaffolding molecule that simultaneously recruited both Dishevelled (Dvl) and protein kinase C delta (PKC delta) through the membrane-spanning C-terminal region to form a complex that stimulated extracellular signal-regulated kinase (ERK)/activating protein-1 (AP-1) via a PKC delta component but also organised the actin filament via a Dvl component. The KITENIN complex controlled the invasiveness of CRC cells aetiologically harbouring various mutations in APC, beta-catenin or K-ras, in which AP-1 activation is redundant but the organisation of the actin filament is indispensable for cell motility. Clinically, KITENIN expression was significantly higher in colon cancer tissues from advanced stage (III, IV) than that of stage I CRC and also in corresponding metastatic tissues.

CONCLUSIONS

The functional KITENIN complex acts as an executor with regard to cell motility and thereby controls CRC cell invasion, which may contribute to promoting metastasis.

KITENIN increases invasion and migration of mouse squamous cancer cells and promotes pulmonary metastasis in a mouse squamous tumor model

KAI1 C-terminal interacting tetraspanin (KITENIN) is reported to promote metastasis in mouse colon cancer models. We investigated the role of KITENIN on the progression of squamous cell carcinoma (SCC). In a preliminary clinical study using resected tissues from head and neck SCC patients, KITENIN was highly expressed in tumors and metastatic lymph nodes, while KAI1 was more increased in adjacent mucosa than in tumor. KITENIN-transfected mouse squamous cancer (SCC VII/KITENIN) cells showed significantly higher invasion, migration, and proliferation than empty vector-transfected cells. In syngeneic mouse squamous tumor models, more increased tumor volume and enhanced lung metastasis were found in SCC VII/KITENIN cells-injected mice. Thus, KITENIN increases invasion and migration of squamous cancer cells and thereby promotes distant metastasis in mouse squamous tumor models.

Activation of Histone Deacetylase 2 by Inducible Heat Shock Protein 70 in Cardiac Hypertrophy

Diverse cardiac diseases induce cardiac hypertrophy, which leads to dilatation and heart failure. We previously reported that hypertrophy can be blocked by class I histone deacetylase (HDAC) inhibitor, which prompted us to investigate the regulatory mechanism of class I HDACs. Cardiac hypertrophy was introduced by aortic banding, by infusion of isoproterenol or angiotensin II, or by swimming. Hypertrophic stimuli transiently elevated the activity of histone deacetylase-2 (Hdac2), a class I HDAC. In cardiomyocytes, forced expression of Hdac2 simulated hypertrophy in an Akt-dependent manner, whereas enzymatically inert Hdac2 H141A failed to do so. Hypertrophic stimuli induced the expression of heat shock protein (Hsp)70. The induced Hsp70 physically associated with and activated Hdac2. Hsp70 overexpression produced a hypertrophic phenotype, which was blocked either by siHdac2 or by a dominant negative Hsp70ΔABD. In Hsp70.1 −/− mice, cardiac hypertrophy and Hdac2 activation were significantly blunted. Heat shock either to cardiomyocytes or to mice activated Hdac2 and induced hypertrophy. However, heat shock-induced Hdac2 activation was blunted in the cardiomyocytes isolated from Hsp70.1 −/− mice. These results suggest that the induction of Hsp70 in response to diverse hypertrophic stresses and the ensuing activation of HDAC2 trigger cardiac hypertrophy, emphasizing HSP70/HDAC2 as a novel mechanism regulating hypertrophy.

Isothiocyanate NB7M causes selective cytotoxicity, pro-apoptotic signalling and cell-cycle regression in ovarian cancer cells

The present report identifies indole-3-ethyl isothiocyanate NB7M as a potent cytotoxic agent with selective activity against cell lines derived from various tumour types. Ovarian cancer cell lines showed sensitivity to NB7M (60–70% cytotoxicity at 2.5 μM), in contrast to control cells (TCL-1 and HTR-8; IC₅₀ ∼15 μM). In a screen performed by the National Cancer Institute (NCI) (NCI₆₀ cancer cell-line assay) NB7M (NSC746077) reduced growth up to 100% with an IC₅₀ between 0.1 and 10 μM depending on the cell line studied. Using SKOV-3 ovarian cancer cells as a model, mechanisms of cytotoxicity were analysed. NB7M caused hallmarks of apoptosis such as PARP-1 deactivation, chromatin condensation, DNA nicks, activation of caspases-9, -8, -3, loss of mitochondrial transmembrane depolarisation potential and upregulation of pro-apoptotic mitogen activated protein kinases (p38, SAP/JNK). NB7M downregulated phosphorylation of prosurvival kinases (PI-3K, AKT, IKKα), transcription factor NF-κB, and expression of DNA-Pk and AXL receptor tyrosine kinase. Subcytotoxic doses of NB7M inhibited DNA synthesis, caused G1-phase cell-cycle arrest and upregulated p27 expression. The present report suggests that NB7M is a selective cytotoxic agent in vitro for cell lines derived from ovarian and certain other tumours. In addition, NB7M acts as a growth/cell-cycle-suppressing agent and may be developed as a potential therapeutic drug to treat ovarian cancer.

Automated quantification of retinal nerve fiber layer atrophy in fundus photograph

Quantitative analysis of the retinal nerve fiber layer (RNFL) defect is prerequisite in the early detection and management of glaucoma. A new automatic quantification method to evaluate the degree of RNLF defect has been proposed in this paper. Simple image processing technique is applied to locate optic disc and intensity of the pixels around optic disc is plotted. The area with RNFL defect can be easily determined by comparing the intensity plot of the RNFL and the first derivative of the intensity plot. Through analysis of the plot, thickness of RNFL also can be postulated.

Selective blockade of Ca2+ permeable AMPA receptors in CA1 area of rat hippocampus

Using whole cell patch-clamp recording from pyramidal cells and interneurons in the CA1 area of hippocampal slices, the effect of IEM-1460, a selective channel blocker of Ca2+ permeable AMPA receptors (AMPARs), on postsynaptic currents (PSCs) was studied. Excitatory postsynaptic currents (EPSCs) were evoked by stimulation of Schaffer collaterals (SCs) in the presence of APV and bicuculline to pharmacologically isolate the EPSCs mediated by AMPAR activation. IEM-1460 (50 microM) did not affect the amplitude of EPSCs in CA1 pyramidal cells but reversibly decreased their amplitude in interneurons of pyramidal layer (15 cells), radiatum (37 cells) and border radiatum-lacunosum-moleculare (R-LM) (55 cells) layers. The ability of IEM-1460 to decrease EPSC amplitude correlated with EPSC rectification properties in CA1 interneurons, providing evidence for synaptic localization of Ca2+ permeable AMPARs at the SC synaptic input. Independent of their localization, the majority of interneurons studied exhibited only modest sensitivity to IEM-1460 (EPSC amplitude decreased by less than 30%), while in 15% of interneurons IEM-1460 induced more than 50% reduction in EPSC amplitude. To reveal possible afferent-specific localization of Ca2+ permeable AMPARs on R-LM interneurons, the effect of IEM-1460 on EPSCs evoked by stimulation of SC was compared with that of perforant path (PP). Although average sensitivities did not differ significantly, in 61% of R-LM layer interneurons, the SC-evoked EPSCs exhibited higher sensitivity to IEM-1460 than the PP-evoked EPSCs. Moreover, in 54% of R-LM layer interneurons the EPSCs evoked by SC stimulation were complex, having an initial peak followed by one or several late components. Kinetics, latency distribution and reversal potential of late components suggest di- and polysynaptic origin of the late components. Late EPSCs were strongly and reversibly inhibited by IEM-1460 indicating that Ca2+ permeable AMPARs are involved in the indirect excitation of R-LM layer interneurons. Despite the ability to decrease the excitatory synaptic input to interneurons, IEM-1460 did not affect interneuron-mediated inhibitory postsynaptic currents (IPSCs) evoked in pyramidal neurons by SC stimulation. These data suggest that interneurons with a synaptic input highly sensitive to IEM-1460 do not contribute specifically to the feed-forward inhibition of hippocampal pyramidal neurons.

Enhancer of polycomb1, a novel homeodomain only protein-binding partner, induces skeletal muscle differentiation

Homeodomain only protein, Hop, is an unusual small protein that modulates target gene transcription without direct binding to DNA. Here we show that Hop interacts with Enhancer of Polycomb1 (Epc1), a homolog of a Drosophila polycomb group gene product that regulates transcription, to induce the skeletal muscle differentiation. Yeast two-hybrid assay with the human adult heart cDNA library revealed that Hop can associate with Epc1. The amino-terminal domain of Epc1 as well as full Epc1 physically interacted with Hop in mammalian cells and in yeast. Epc1 is highly expressed in the embryonic heart and adult skeletal muscles. Serum deprivation induced differentiation of H9c2, a myoblast cell line, into skeletal myocytes, and Epc1 was up-regulated. Differentiation of H9c2 was induced by Epc1 overexpression, although it was severely impaired in Epc1-knockdown cells. Co-transfection of Hop potentiated Epc1-induced transactivation of myogenin and myotube formation. Hop knock-out mice elicited a decrease in myosin heavy chain and myogenin expressions in skeletal muscle and showed delay in hamstring muscle healing after injury. Differentiation was impaired in skeletal myoblasts from Hop knock-out mice. These results suggest that Epc1 plays a role in the initiation of skeletal muscle differentiation, and its interaction with Hop is required for the full activity.

MafB negatively regulates RANKL-mediated osteoclast differentiation

Receptor activator of nuclear factor kappaB ligand (RANKL) induces osteoclast formation from hematopoietic cells via regulation of various transcription factors. Here, we show that MafB negatively regulates RANKL-induced osteoclast differentiation. Expression levels of MafB are significantly reduced by RANKL during osteoclastogenesis. Overexpression of MafB in bone marrow-derived monocyte/macrophage lineage cells (BMMs) inhibits the formation of TRAP(+) multinuclear osteoclasts, but phagocytic activity of BMMs is retained. Furthermore, overexpression of MafB in BMMs attenuates the gene induction of NFATc1 and osteoclast-associated receptor (OSCAR) during RANKL-mediated osteoclastogenesis. In addition, MafB proteins interfere with the DNA-binding ability of c-Fos, Mitf, and NFATc1, inhibiting their transactivation of NFATc1 and OSCAR. Furthermore, reduced expression of MafB by RNAi enhances osteoclastogenesis and increases expression of NFATc1 and OSCAR. Taken together, our results suggest that MafB can act as an important modulator of RANKL-mediated osteoclastogenesis.

Presenilin-1 inhibits delta-catenin-induced cellular branching and promotes delta-catenin processing and turnover

Although delta-catenin/neural plakophilin-related armadillo protein (NPRAP) was reported to interact with presenilin-1 (PS-1), the effects of PS-1 on delta-catenin have not been established. In this study, we report that overexpression of PS-1 inhibits the delta-catenin-induced dendrite-like morphological changes in NIH 3T3 cells and promotes delta-catenin processing and turnover. The effects of PS-1 on endogenous delta-catenin processing were confirmed in hippocampal neurons overexpressing PS-1, as well as in the transgenic mice expressing the disease-causing mutant PS-1 (M146V). In addition, disease-causing mutant PS-1 (M146V and L286V) enhanced delta-catenin processing, whereas PS-1/gamma-secretase inhibitors could block the formation of processed forms of delta-catenin. Together, our findings suggest that PS-1 can affect delta-catenin-induced morphogenesis possibly through the regulation of its processing and stability.

Efficacy of 6-Month Pretransplant Abstinence for Patients With Alcoholic Liver Disease Undergoing Living Donor Liver Transplantation

PURPOSE

Questions have been raised regarding the ethics of liver transplantation in patients with alcoholic liver disease (ALD), including the fairness of cadaveric organ allocation to individuals who abuse alcohol and the efficacy of transplantation in these patients, many of whom may relapse. Living donor liver transplantation (LDLT) for ALD patients raises the similar ethical issues. ALD candidates for cadaveric liver transplants are required to abstain from alcohol for 6 months before being listed, but the efficacy of 6 months of abstinence in ALD patients receiving LDLT is not known.

METHODS

We therefore determined the efficacy of 6 months of pretransplant abstinence in 15 ALD patients who underwent LDLT from February 1997 to December 2003.

RESULTS

The Model for End-stage Liver Disease score was 24 +/- 10, and mean pretransplant abstinence period was 15 +/- 13 months, with 11 (73.3%) patients being abstinent for at least 6 months. Four patients received dual grafts, making the number of living donors 19: 12 children, two wives, one brother, three nephews, and one aunt. There were no unrelated donors. Three patients showed a relapse to alcohol drinking. The overall 1-, 3-, and 5-year survival rates were 100%, 100%, and 87.5%, respectively, and the cumulative 1-, 3-, and 5-year relapse rates were 6.7%, 20%, and 20%, respectively. The relapse rates in patients who did and did not maintain 6 months of abstinence were 9.1% and 50%, respectively; this difference was not significant (P = .154), likely due to the small sample size. Younger recipient age was a significant risk factor for alcohol relapse (40 +/- 8 years versus 53 +/- 6 years; P = .004).

CONCLUSIONS

Pretransplant abstinence of 6 months seemed to be beneficial. For ethical reasons, a 6-month abstinence rule should be strictly observed in LDLT.

A repressor complex, AP4 transcription factor and geminin, negatively regulates expression of target genes in nonneuronal cells

The transcription of neuron-specific genes must be repressed in nonneuronal cells. REST/NRSF is a transcription factor that restricts the expression of many neuronal genes through interaction with the neuron-restrictive silencer element at the promoter level. PAHX-AP1 is a neuronal gene that is developmentally up-regulated in the adult mouse brain but that has no functional NRSE motif in its 5' upstream sequence. Here, we report that the transcription factor AP4 and the corepressor geminin form a functional complex in which SMRT and histone deacetylase 3 are recruited. The functional complex represses PAHX-AP1 expression in nonneuronal cells and participates in regulating the developmental expression of PAHX-AP1 in the brain. This complex also serves as a transcriptional repressor of DYRK1A, a candidate gene for Down's syndrome. Furthermore, compared with that in normal fetal brain, the expression of AP4 and geminin is reduced in Down's syndrome fetal brain at 20 weeks of gestation age, at which time premature overexpression of dual-specificity tyrosine-phosphorylated and regulated kinase 1A (DYRK1A) is observed. Our findings indicate that AP4 and geminin act as a previously undescribed repressor complex distinct from REST/NRSF to negatively regulate the expression of target genes in nonneuronal cells and suggest that the AP4-geminin complex may contribute to suppressing the precocious expression of target genes in fetal brain.

Ketanserin, a 5-HT2 antagonist, directly inhibits the ATP-sensitive potassium channel in mouse ventricular myocytes

The effects of ketanserin, a 5-HT2 antagonist, on the ATP-sensitive K+ (K(ATP)) channels were studied in mouse ventricular myocytes using patch clamp technique. Under the whole-cell voltage clamp conditions, ketanserin (1-100 microM) reversibly inhibited pinacidil-induced K(ATP) current in a concentration-dependent fashion with a Ki value of 9.36 microM and the Hill coefficient was 0.67. This inhibition was developed even with the presence of 5-hydroxytryptamine (100 microM) in the bath. Prazosin, a selective alpha1-antagonist, also failed to mimic the effect of ketanserin. Ketanserin did not affect the channel activity in inside-out configuration under the ATP-free internal solution. Furthermore, ketanserin applied to the external solution did not affect the pinacidil-induced channel activity in the cell-attached patches, but did inhibit it when applied into the pipette. These results suggest that the inhibitory action of ketanserin observed in this study was probably due to a direct action on the K(ATP) channel rather than to an action through the 5-HT2 receptor or alpha1-adrenoceptor blockade, and that the antiarrhythmic activity of ketanserin against cardiac arrhythmias induced in the ischemic/reperfused heart is at least in part attributable to its inhibition of the K(ATP) channel.

Influence of weight reduction by sibutramine on female sexual function

BACKGROUND

It is well known that selective serotonin reuptake inhibitors (SSRIs) can cause sexual dysfunction, so it is possible that sibutramine, a serotonin and norepinephrine reuptake inhibitor, could induce sexual dysfunction.

DESIGN AND SUBJECTS

The effect of sibutramine on sexual function was evaluated in 46 overweight and obese (body mass index (BMI) > or = 23 kg/m2) but otherwise healthy married women (28-44 years). Participants were randomly assigned at baseline to either the sibutramine or control group. The Female Sexual Function Index (FSFI) questionnaire was used to assess sexual function at baseline and after treatment with behavioral therapy plus sibutramine 10 mg once daily or behavioral therapy alone (control) for 8 weeks.

RESULTS

Mean weight loss from baseline to week 8 was -6.03% in sibutramine group and -0.38% in the control group. There was significant improvement of FSFI total score, arousal domain score and lubrication domain score in the sibutramine group (P<0.05), and significant differences in arousal, orgasm, satisfaction domain score and total score (P<0.05) in favor of sibutramine. Decreases in body weight and BMI were correlated with the improvement of arousal (r = -0.44 and r = -0.48, respectively) and orgasm (r = -0.45 and r = -0.46, respectively) domains.

CONCLUSION

Treatment with sibutramine plus behavioral therapy did not induce sexual dysfunction and sibutramine-induced weight reduction appeared to have a positive impact on sexual function in this small group of overweight and moderately obese women. The degree of improvement in sexual function was correlated with the degree of weight reduction.

Brain-specific angiogenesis inhibitor 2 regulates VEGF through GABP that acts as a transcriptional repressor

Previously, we reported that decreased brain-specific angiogenesis inhibitor 2 (BAI2) induced increased VEGF expression. The regulatory mechanisms for this process are not understood. Here we show that GA-binding protein gamma (GABPgamma) associates with the cytoplasmic domain of BAI2, and GABPalpha/gamma or GABPalpha/beta works as a transcriptional repressor of VEGF in SHSY5Y cells. Transcriptional activity of wild-type VEGF promoter was significantly increased in anti-sense BAI2-transfected cells, but not that of VEGF promoter harboring mutated GABP sites. In in vivo focal cerebral ischemia model, the decrease in BAI2 accompanied by decreased GABPalpha and GABPgamma elicited increased VEGF expression before the onset of HIF-1alpha. Our results point out that BAI2 controls VEGF transcription through GABP under normal conditions and cerebral ischemia.

Inhibition of Histone Deacetylation Blocks Cardiac Hypertrophy Induced by Angiotensin II Infusion and Aortic Banding

Background— A number of distinct stress signaling pathways in myocardium cause cardiac hypertrophy and heart failure. Class II histone deacetylases (HDACs) antagonize several stress-induced pathways and hypertrophy. However, cardiac hypertrophy induced by transgenic overexpression of the homeodomain only protein, HOP, can be prevented by the nonspecific HDAC inhibitors trichostatin A and valproic acid, suggesting that alternate targets that oppose class II HDAC function might exist in myocardium. We tested the effects of several HDAC inhibitors, including a class I HDAC-selective inhibitor, SK-7041, on cardiac hypertrophy induced by angiotensin II (Ang II) treatment or aortic banding (AB).

Methods and Results— Cardiac hypertrophy was induced by chronic infusion of Ang II or by AB in mice or rats and evaluated by determining the ratio of heart weight to body weight or to tibia length, cross-sectional area, or echocardiogram. Cardiac hypertrophy induced by Ang II or AB for 2 weeks was significantly reduced by simultaneous administration of trichostatin A, valproic acid, or SK-7041. Echocardiogram revealed that exaggerated left ventricular systolic dimensions were relieved by HDAC inhibitors. HDAC inhibitors partially reversed preestablished cardiac hypertrophy and improved survival of AB mice. The expressions of atrial natriuretic factor, α-tubulin, β-myosin heavy chain, and interstitial fibrosis were reduced by HDAC inhibition.

Conclusions— These results suggest that the predominant effect of HDAC inhibition, mainly mediated by class I HDACs, is to prevent cardiac hypertrophy in response to a broad range of agonist and stretch stimuli.