Ryoichi Asaka

Sirtuin 1 promotes the growth and cisplatin resistance of endometrial carcinoma cells: a novel therapeutic target.

Sirtuin 1 (SIRT1), originally identified as a longevity gene, is induced by caloric restriction, and regulates various cellular functions including DNA repair, cell survival and metabolism via the deacetylation of target proteins such as histone and p53. These functions are considered to act dualistically as preventing or facilitating cancer. This study aimed to clarify the expression and role of SIRT1 in endometrial carcinoma. Because a high-calorie diet was a well-known risk factor for endometrial carcinoma, we first hypothesized that SIRT1 might be downregulated in normal endometrial glandular cells of obese women. However, no correlation was observed between the expression of SIRT1 and body mass index (BMI). In contrast, regardless of BMI, the immunohistochemical expression of SIRT1 was significantly higher in endometrial carcinoma (108 cases) than in normal endometria (60 cases) (P<0.05), and its overexpression was associated with a shorter survival (P<0.05). Our experiments in vivo revealed that SIRT1 accelerated the proliferation of endometrial carcinoma cell lines (HHUA, HEC151, and HEC1B). SIRT1 overexpression significantly enhanced the resistance for cisplatin and paclitaxel in HHUA cells. Although p53 is an important target protein for SIRT1, the selective SIRT1 inhibitor (EX527) significantly suppressed the proliferation and cisplatin resistance of three endometrial carcinoma cell lines regardless of the p53 mutation status. In addition, SIRT1 overexpression in HHUA cells accelerated tumor growth and cisplatin resistance in nude mice, and EX527 significantly suppressed the growth of tumors of HHUA and HEC1B cells. No adverse effect of EX527 was observed in these mice. In conclusion, SIRT1 is involved in the acquisition of the aggressive behavior associated with endometrial carcinoma, and the SIRT1 inhibitor, EX527, may be a useful agent for the treatment of this malignancy.

Overexpression of Sirt1 is Associated With Poor Outcomes in Patients With Ovarian Carcinoma.

Sirtuin 1 (SIRT1), originally identified as a longevity gene, regulates DNA repair and metabolism by deacetylating target proteins such as p53. SIRT1 plays a key role in the pathophysiology of metabolic diseases and neurodegenerative disorders, and is considered to protect against age-related diseases including cancer. In contrast, SIRT1 may be oncogenic because its overexpression has been detected in many cancers. The aim of the present study was to clarify the expression and the role of SIRT1 in ovarian carcinoma (OvCa). The expression of SIRT1 was evaluated immunohistochemically in 16 cases of normal ovaries, 35 cases of endometriosis with/without carcinoma, and 68 cases of OvCa (endometrioid, 16; clear cell, 20; mucinous, 16; serous, 16). Staining results were evaluated semiquantitatively by the Immunoreactive Scoring System, and the relationships with clinicopathologic features and outcomes of patients were analyzed. The expression of SIRT1 was higher in endometrioid, mucinous, and clear-cell carcinomas than in the inclusion cysts of normal ovaries, but not in serous carcinoma (P=0.038). The expression of SIRT1 on OvCa did not correlate with age, stage, location of metastasis, or capsular penetration. However, elevated SIRT1 expression was a significant predictor of shorter survival in univariate (P=0.038) and multivariate (P=0.037) survival analyses, regardless of the tumor stage. Results of the present study suggest a positive role for SIRT1 in the development of OvCa and its potential as a novel therapeutic target.

Lipocalin 2 Enhances Migration and Resistance against Cisplatin in Endometrial Carcinoma Cells

Purpose Lipocalin 2 (LCN2) is a secretory protein that is involved in various physiological processes including iron transport. We previously identified LCN2 as an up-regulated gene in endometrial carcinoma, and found that the overexpression of LCN2 and its receptor, SLC22A17, was associated with a poor prognosis. However, the functions and mechanism of action of LCN2 currently remain unclear. Methods The LCN2-overexpressing endometrial carcinoma cell lines, HHUA and RL95-2, and LCN2-low-expressing one, HEC1B, were used. The effects of LCN2 on cell migration, cell viability, and apoptosis under various stresses, including ultraviolet (UV) irradiation and cisplatin treatment, were examined using the scratch wound healing assay, WST-1 assay, and Apostrand assay, respectively. Results LCN2-silencing using shRNA method significantly reduced the migration ability of cells (p<0.05). Cytotoxic stresses significantly decreased the viability of LCN2-silenced cells more than that of control cells. In contrast, LCN2 overexpression was significantly increased cisplatin resistance. These effects were canceled by the addition of the iron chelator, deferoxamine. After UV irradiation, the expression of phosphorylated Akt (pAkt) was decreased in LCN2-silenced cells, and the PI3K inhibitor canceled the difference induced in UV sensitivity by LCN2. The cisplatin-induced expression of pAkt was not affected by LCN2; however, the expression of p53 and p21 was increased by LCN2-silencing. Conclusions These results indicated that LCN2 was involved in the migration and survival of endometrial carcinoma cells under various stresses in an iron-dependent manner. The survival function of LCN2 may be exerted through the PI3K pathway and suppression of the p53-p21 pathway. These functions of LCN2 may increase the malignant potential of endometrial carcinoma cells.

SIRT1 Regulates the Chemoresistance and Invasiveness of Ovarian Carcinoma Cells

BACKGROUND: SIRT1 is a longevity gene that forestalls aging and age-related diseases including cancer, and has recently attracted widespread attention due to its overexpression in some cancers. We previously identified the overexpression of SIRT1 in ovarian carcinoma (OvCa) as a poor prognostic factor. However, mechanistic insights into the function of SIRT1 in OvCa have yet to be elucidated. METHODS: Quantitative real-time reverse PCR (qRT-PCR) and Western blotting were employed to examine the expression of SIRT1 in a panel of human OvCa cell lines. si-RNA or sh-RNA and cDNA technologies were utilized to knockdown or overexpress SIRT1, respectively. The effects of SIRT1 on proliferation and chemoresistance were examined using a WST-1 assay, and the underlying mechanisms were confirmed using an apoptotic assay, and the quantification of glutathione (GSH), and reactive oxygen species (ROS). The aggressiveness of SIRT1 was analyzed using in vitro invasion and migration assays. RESULTS: SIRT1 was more strongly expressed in OvCa cell lines than in the immortalized ovarian epithelium at the gene and protein levels. Stress up-regulated the expression of SIRT1 in dose- and time-dependent manners. SIRT1 significantly enhanced the proliferation (P < .05), chemoresistance (P < .05), and aggressiveness of OvCa cells by up-regulating multiple antioxidant pathways to inhibit oxidative stress. Further study into the overexpression of SIRT1 demonstrated the up-regulation of several stemness-associated genes and enrichment of CD44v9 via an as-yet-unidentified pathway. CONCLUSIONS: Our results suggest that SIRT1 plays a role in the acquisition of aggressiveness and chemoresistance by OvCa, and has potential as a therapeutic target for OvCa.

Lipocalin 2 attenuates iron-related oxidative stress and prolongs the survival of ovarian clear cell carcinoma cells by up-regulating the CD44 variant

ABSTRACT Ovarian clear cell carcinoma (CCC) arises from ovarian endometriosis. Intra-cystic fluid contains abundant amounts of free iron, which causes persistent oxidative stress, a factor that has been suggested to induce malignant transformation. However, the mechanisms linking oxidative stress and carcinogenesis in CCC currently remain unclear. Lipocalin 2 (LCN2), a multifunctional secretory protein, functions as an iron transporter as well as an antioxidant. Therefore, we herein examined the roles of LCN2 in the regulation of intracellular iron concentrations, oxidative stress, DNA damage, and antioxidative functions using LCN2-overexpressing (ES2), and LCN2-silenced (RMG-1) CCC cell lines. The results of calcein staining indicated that the up-regulated expression of LCN2 correlated with increases in intracellular iron concentrations. However, a DCFH-DA assay and 8OHdG staining revealed that LCN2 reduced intracellular levels of reactive oxygen species and DNA damage. Furthermore, the expression of LCN2 suppressed hydrogen peroxide-induced apoptosis and prolonged cell survival, suggesting an antioxidative role for LCN2. The expression of mRNAs and proteins for various oxidative stress-catalyzing enzymes, such as heme oxygenase (HO), superoxide dismutase (SOD), and glutathione peroxidase, was not affected by LCN2, whereas the intracellular concentration of the potent antioxidant, glutathione (GSH), was increased by LCN2. Furthermore, the expression of xCT, a cystine transporter protein, and CD44 variant 8-10 (CD44v), a stem cell marker, was up-regulated by LCN2. Although LCN2 increased intracellular iron concentrations, LCN2-induced GSH may catalyze and override oxidative stress via CD44v and xCT, and subsequently enhance the survival of CCC cells in oxidative stress-rich endometriosis.

Immunohistochemical expression of core 2 β1,6‐N‐acetylglucosaminyl transferase 1 (C2GnT1) in endometrioid‐type endometrial carcinoma: a novel potential prognostic factor

It has been reported that the expression of core 2 β1,6‐N‐acetylglucosaminyl transferase 1 (C2GnT1), which synthesizes the core 2 branching structure on O‐glycans, may be associated with the biological aggressiveness of tumour cells. Therefore, the aim of this study was to examine the relationship between the expression of C2GnT1 and clinicopathological parameters of patients with endometrial carcinoma.

Mutation analysis by whole exome sequencing of endometrial hyperplasia and carcinoma in one patient: Abnormalities of polymerase epsilon and the phosphatidylinositol‐3 kinase pathway

In order to understand the role of gene mutations in endometrial carcinogenesis, whole exome sequencing via laser microdissection was performed in the normal endometrium, atypical endometrial hyperplasia and endometrial carcinoma in the same patient. A total of 4046 and 5746 mutations with amino acid substitution were detected in endometrial hyperplasia and endometrial carcinoma, respectively; 2252 were common in both tissues and might play crucial roles in early carcinogenesis. These common mutations included polymerase epsilon (POLE) and DNA mismatch repair (MMR) genes, indicating that an ultra‐mutated phenotype, and also included PTEN and PIK3CA. The mutation‐prone environment evoked by mutations in the POLE and MMR genes associated with the activated phosphatidylinositol‐3 kinase pathway played a pivotal role in this case.

Prenatal sonographic diagnosis of fetal valproate syndrome: a case report

BackgroundPrenatal exposure of mother to valproate (VPA) causes teratogenic effects in the fetus, namely fetal valproate syndrome (FVS). We report a case of fetal valproate syndrome rarely diagnosed by prenatal sonographic examination.Case presentationOur patient was a female infant who was born to a 27-year-old nulliparous Japanese woman with epilepsy. The mother was diagnosed with infantile epilepsy at 1 year of age and had been using three antiepileptic drugs, including valproate, but preconceptional counseling was not performed. At 25 weeks of gestation, contracture of the fetal right wrist joint suggestive of a radial ray defect was observed by transabdominal ultrasonography. The fetus demonstrated growth retardation starting from 32 weeks of gestation. In addition, saddle nose as a facial anomaly was detected by three-dimensional ultrasound at 37 weeks of gestation. Accordingly, we suspected that the fetus had fetal valproate syndrome. At 39 weeks of gestation, the mother delivered an infant weighing 2056 g. The neonate had characteristic features of fetal valproate syndrome, such as facial configuration, slight muscular hypotonia of the whole body, breathing problems, right-hand articular contracture accompanied by radial ray defect, and cardiovascular malformation.ConclusionsWhen obstetricians manage epileptic pregnant women without enough preconceptional counseling or adjustment for antiepileptic drugs, careful sonographic observation of the fetus is mandatory.

Management of a Pregnant Woman with Idiopathic Interstitial Pneumonia Accompanied by Secondary Pulmonary Hypertension: Case Report and Literature Review

Idiopathic interstitial pneumonias (IIPs) typically occur in the fifth and sixth decades, and thus are uncommon in the child-bearing age group. We herein report an extremely rare case of a pregnant woman with IIP accompanied by secondary pulmonary hypertension that had a successful cesarean delivery. A 36-year-old primigravida woman was referred to our Obstetrics department at 6 weeks of gestation. Seven years ago, she had a dry cough and moderate dyspnea, and was diagnosed with non-specific interstitial pneumonia (NSIP), a subtype of IIP. At 11 weeks of gestation, spirometry showed a vital capacity of 1.89 L (60% of predicted). An arterial blood gas analysis showed PaO2 of 77.2 mmHg and oxygen saturation of 95% in breathing room air at rest. An echocardiogram revealed mild pulmonary hypertension; systolic pulmonary artery blood pressure (PABP) of 44 mmHg. Fetal growth and amniotic fluid volume were normal. Our management plan was to maintain oxygen saturation at more than 95% of oxygen saturation and systolic PABP at less than 50 mmHg. Oxygen therapy was initiated at 13 weeks of gestation because of dyspnea at rest. At 28 weeks of gestation, an echocardiogram showed severe pulmonary hypertension with systolic PABP of 64 mmHg. Therefore, we performed cesarean section at 30 weeks of gestation. The newborn was a male weighing 1.452 g with Apgar scores of 6 and 7 at 1 min and 5 min, respectively. Although the patient’s post-operative course was uneventful, she was discharged on a regimen of oxygen therapy. The effects of pregnancy on IIPs remain unclear because of its extreme rarity. In the management of pregnant women with IIPs accompanied by secondary pulmonary hypertension, the maintenance of systolic PABP of less than 50 mmHg on an echocardiogram may be effective.

Elevated Serum Levels of Estradiol Induce Endometrial Hyperplasia Rather than Carcinoma in a Mouse Model Using a Carcinogen

Objective: Although estrogen has been regarded as a risk factor for endometrial carcinoma, its concentrationdependent carcinogenetic effects remain unclear, because most endometrial carcinomas occur in post-menopausal women, whose serum estrogen levels are relatively low. We previously reported that high levels of estradiol (E2) may suppress endometrial carcinogenesis by up-regulating DNA mismatch repair (MMR) in vitro. The present study was undertaken to further examine the carcinogenetic role of estrogen at various concentrations in vivo. Methods: N-methyl-N-nitrosourea (MNU) was injected into the uterine cavity of 29 mice, and E2 was administered by pellets or orally. Uteri were removed for histological examinations 24 weeks later, and serum E2 levels were measured. The immunohistochemical expression of MMR proteins in uterine epithelia was investigated. Results: Of 29 mice, 8, 8, 8, and 5 showed atrophic, normal, hyperplastic, and carcinomatous endometria, respectively. The mean E2 levels of each group were 0.2 pg/ml, 3.8 pg/ml, 190.0 pg/ml, and 6.7 pg/ml, with significant differences. The expression of the MMR proteins was stronger in mice with elevated E2. Conclusion: Elevated E2 levels preferentially induced endometrial hyperplasia rather than carcinoma, and this may be mediated by MMR proteins. These results indicate that modest E2 is needed, whereas elevated E2 levels are not necessarily advantageous for carcinogenesis, suggesting the importance of low-chronic (un-opposed) estrogen in human endometrial carcinogenesis.