Successful Laparoscopic Treatment of Small-bowel Obstruction in Early Pregnancy.

Small-bowel obstruction (SBO) during pregnancy is uncommon and can be difficult to diagnose. Therefore, the condition is associated with significant maternal and fetal mortality. We report a case of successful laparoscopic treatment of SBO in early pregnancy. A 37-year-old woman presented with diffuse abdominal pain and vomiting at 8 weeks of gestation. She had a history of abdominal surgery. Exploratory laparoscopy was performed by a gastrointestinal surgeon because SBO, and specifically strangulated ileus, was strongly suspected. On entry into the abdomen, dilated small bowel was visible in the pelvis; this was attached to the pelvic wall and twisted near the right adnexa. The small bowel initially appeared dark and congested, but after releasing the adhesions, it regained its normal color, was viable, and peristalsis was observed. Therefore, bowel resection was not required. No recurrence was observed after food ingestion, and the patient was discharged 12 days after surgery.

A phase II study of irinotecan combined with S-1 in patients with advanced or recurrent cervical cancer previously treated with platinum based chemotherapy.

OBJECTIVES: We conducted a phase II study to investigate the efficacy and toxicities of irinotecan plus oral S-1 in patients with advanced or recurrent uterine cervical cancer. METHODS: Patients with advanced or recurrent cervical cancer previously treated with platinum based chemotherapy were enrolled. Irinotecan (150 mg/m2) was administered intravenously over the course of 90 min on day 1, and S-1 (80 mg/m2) was given orally in two divided doses from days 1 to 14 of a 21 day cycle. The primary endpoint of this phase II study was response rate. Secondary endpoints included safety, progression free survival, and overall survival. RESULTS: A total of 19 patients were enrolled and treated. The response rate was 29.4%. Grade 3-4 hematologic toxicities were observed in three patients (15.7%). The only grade 3-4 non-hematologic toxicity observed was grade 3 diarrhea. The median progression free survival and overall survival were 3 months and 9 months, respectively. CONCLUSION: S-1 plus irinotecan in a 3 weekly setting is safe and active in women with advanced or recurrent cervical cancer previously treated with platinum based chemotherapy. Future corroborative clinical studies are warranted.

The significance of G-CSF expression and myeloid-derived suppressor cells in the chemoresistance of uterine cervical cancer.

Granulocyte-colony stimulating factor (G-CSF) producing malignant tumor has been reported to occur in various organs, and has been associated with poor clinical outcome. The aim of this study is to investigate the significance of tumor G-CSF expression in the chemosensitivity of uterine cervical cancer. The clinical data of recurrent or advanced cervical cancer patients who were treated with platinum-based chemotherapy were analyzed. Clinical samples, cervical cancer cell lines, and a mouse model of cervical cancer were employed to examine the mechanisms responsible for the development of chemoresistance in G-CSF-producing cervical cancer, focusing on myeloid-derived suppressor cells (MDSC). As a result, the tumor G-CSF expression was significantly associated with increased MDSC frequencies and compromised survival. In vitro and in vivo experiments demonstrated that the increased MDSC induced by tumor-derived G-CSF is involved in the development of chemoresistance. The depletion of MDSC via splenectomy or the administration of anti-Gr-1 antibody sensitized G-CSF-producing cervical cancer to cisplatin. In conclusion, tumor G-CSF expression is an indicator of an extremely poor prognosis in cervical cancer patients that are treated with chemotherapy. Combining MDSC-targeting treatments with current standard chemotherapies might have therapeutic efficacy as a treatment for G-CSF-producing cervical cancer.

IKKß Regulates VEGF Expression and Is a Potential Therapeutic Target for Ovarian Cancer as an Antiangiogenic Treatment.

The prolongation of progression-free survival (PFS) in patients with advanced ovarian cancer by antiangiogenic therapy has been shown in several clinical trials. However, although an anti-VEGF antibody (bevacizumab) is the only option currently available, its efficacy is limited and it is not cost effective for use in all patients. Therefore, the development of a novel antiangiogenic drug, especially composed of small-molecule compounds, could be a powerful armament for ovarian cancer treatment. As NF-κB signaling has the potential to regulate VEGF expression, we determined to identify whether VEGF expression is associated with NF-κB activation and to investigate the possibility of a novel IKKß inhibitor, IMD-0354 (IMMD Inc.), as an antiangiogenic drug. Tissue microarrays from 94 ovarian cancer tissues were constructed and immunohistochemical analyses performed. We revealed that IKK phosphorylation is an independent prognostic factor (PFS: 26.1 vs. 49.8 months, P = 0.011), and is positively correlated with high VEGF expression. In in vitro analyses, IMD-0354 robustly inhibited adhesive and invasive activities of ovarian cancer cells without impairing cell viabilities. IMD-0354 significantly suppressed VEGF production from cancer cells, which led to the inhibition of angiogenesis. In a xenograft model, the treatment of IMD-0354 significantly inhibited peritoneal dissemination with a marked reduction of intratumoral blood vessel formation followed by the inhibition of VEGF expression from cancer cells. IMD-0354 is a stable small-molecule drug and has already been administered safely to humans in other trials. Antiangiogenic therapy targeting IKKß is a potential future option to treat ovarian cancer.

Interleukin 6 receptor is an independent prognostic factor and a potential therapeutic target of ovarian cancer.

Ovarian cancer remains the most lethal gynecologic cancer and new targeted molecular therapies against this miserable disease continue to be challenging. In this study, we analyzed the expressional patterns of Interleukin-6 (IL-6) and its receptor (IL-6R) expression in ovarian cancer tissues, evaluated the impact of these expressions on clinical outcomes of patients, and found that a high-level of IL-6R expression but not IL-6 expression in cancer cells is an independent prognostic factor. In in vitro analyses using ovarian cell lines, while six (RMUG-S, RMG-1, OVISE, A2780, SKOV3ip1 and OVCAR-3) of seven overexpressed IL-6R compared with a primary normal ovarian surface epithelium, only two (RMG-1, OVISE) of seven cell lines overexpressed IL-6, suggesting that IL-6/IL-6R signaling exerts in a paracrine manner in certain types of ovarian cancer cells. Ovarian cancer ascites were collected from patients, and we found that primary CD11b+CD14+ cells, which were predominantly M2-polarized macrophages, are the major source of IL-6 production in an ovarian cancer microenvironment. When CD11b+CD14+ cells were co-cultured with cancer cells, both the invasion and the proliferation of cancer cells were robustly promoted and these promotions were almost completely inhibited by pretreatment with anti-IL-6R antibody (tocilizumab). The data presented herein suggest a rationale for anti-IL-6/IL-6R therapy to suppress the peritoneal spread of ovarian cancer, and represent evidence of the therapeutic potential of anti-IL-6R therapy for ovarian cancer treatment.

Usefulness of duloxetine for Paclitaxel-induced peripheral neuropathy treatment in gynecological cancer patients.

AIM: The present study aimed at evaluating the usefulness and adverse effects of duloxetine treatment for paclitaxel-induced peripheral neuropathy in gynecological cancer patients. PATIENTS AND METHODS: Medical records of gynecological cancer patients treated with duloxetine were retrospectively studied to evaluate the drug's efficacy for paclitaxel-induced peripheral neuropathy. RESULTS: RESULTS from 25 patients showed that an improved response was observed in 14 (56%). By univariate and multivariate analysis, the patient's age, tumor origin, regimen of chemotherapy, accumulated doses of paclitaxel or carboplatin, previous medication, maintenance dosage and timing of treatment with duloxetine were found not to be associated with the effectiveness of duloxetine treatment. Adverse effects with duloxetine were mild and well-tolerated. CONCLUSION: As an option, duloxetine can be effectively used for paclitaxel-induced peripheral neuropathy in patients with gynecological cancers, irrespective of patients' age, origin of the tumor, regimen of chemotherapy, or previous medication.

Preclinical Efficacy for AKT Targeting in Clear Cell Carcinoma of the Ovary.

UNLABELLED: The aim of this study was to determine the role of AKT as a therapeutic target in ovarian clear cell carcinoma (CCC), an aggressive, chemoresistant histologic subtype of ovarian cancer. AKT activation was assessed by immunohistochemistry (IHC) using human tissue microarrays of primary ovarian cancers, composed of both CCC and serous adenocarcinoma (SAC). The growth-inhibitory effect of AKT-specific targeting by the small-molecule inhibitor, perifosine, was examined using ovarian CCC cell lines in vitro and in vivo. Finally, the activity of perifosine was examined using in CCC-derived tumors that had acquired resistance to anti-VEGF or chemotherapeutics such as bevacizumab or cisplatin, respectively. Interestingly, AKT was frequently activated both in early-stage and advanced-stage CCCs. Treatment of CCC cells with perifosine attenuated the activity of AKT-mTORC1 signaling, inhibited proliferation, and induced apoptosis. The effect of perifosine was more profound under conditions of high AKT activity compared with low AKT activity. Increased AKT activation and enhanced sensitivity to perifosine were observed in the context of cisplatin-resistant CCC. Treatment with perifosine concurrently with cisplatin significantly enhanced the antitumor effect of cisplatin. Moreover, perifosine showed significant antitumor activity in CCC-derived tumors that had acquired resistance to bevacizumab or cisplatin. Collectively, these data reveal that AKT is frequently activated in ovarian CCCs and is a promising therapeutic target in aggressive forms of ovarian cancer. IMPLICATIONS: AKT-targeted therapy has value in a first-line setting as well as a second-line treatment for recurrent disease developing after platinum-based chemotherapy or bevacizumab treatment.

miR-92a inhibits peritoneal dissemination of ovarian cancer cells by inhibiting integrin α5 expression.

Ovarian cancer is characterized by widespread peritoneal dissemination and ascites and has a cure rate of only 30%. As has been previously reported, integrin α5 plays a key role in the peritoneal dissemination of ovarian cancer. Our aim was to identify a new miRNA that regulates integrin α5 expression and analyze the therapeutic potential of targeting this miRNA. By using an IHC analysis, we proved that high integrin α5 expression correlates with a poor prognosis in Japanese patients with International Federation of Gynecology and Obstetrics stage III ovarian cancer. Based on an miRNA algorithm search, we identified hsa-mir-92a (miR-92a) as a candidate. The level of miR-92a expression was significantly inversely correlated with ITGA5 expression in various cancer cells. Transfection of precursor miR-92a reduced integrin α5 expression in ovarian cancer cells, which was accompanied by the inhibition of cancer cell adhesion, invasion, and proliferation. miR-92a overexpression reduced the luciferase activity of the ITGA5 3'-untranslated region, suggesting that ITGA5 mRNA is a direct target of miR-92a. In in vivo ovarian cancer xenografts, the enforced expression of miR-92a in HeyA-8 cells suppressed peritoneal dissemination. Although we still have a long way to go before an effective and nontoxic miRNA-based cancer therapy can be introduced into the clinic, the inhibition of integrin α5 expression by targeting miR-92a needs to be explored further for future applications in ovarian cancer treatment.

Low serum concentrations of anti-Müllerian hormone are common in 53 female childhood cancer survivors.

BACKGROUND/AIMS: Gonadal dysfunction is one of the major endocrinological late effects among childhood cancer survivors (CCSs). Periodic screening evaluation of gonadotropins and sex steroids has been recommended, although it remains difficult to predict gonadal function and reproductive capacity in childhood. We evaluated the effects of cancer treatments on the ovarian function of Japanese female CCSs by measuring serum levels of anti-Müllerian hormone (AMH) and gonadotropin. METHODS: This was a retrospective, cross-sectional study at a single hospital. RESULTS: Among 53 female CCSs, 28 (53%) had a decreased AMH level, while only 16 (30%) had an increased follicle-stimulating hormone (FSH) level. AMH was low in all patients with high FSH, while FSH was not elevated in 43% of patients with a low AMH level. AMH was low in 8 of 9 patients with no breast development, 11 of 14 patients with no spontaneous menstruation, and 3 of 22 patients with regular menstrual cycles. CONCLUSION: Measurement of AMH concentration is useful as a marker of ovarian reserve in female CCSs for detecting primary gonadal deficiency, particularly among patients without increased gonadotropin levels.

Balloon tamponade during cesarean section is useful for severe post-partum hemorrhage due to placenta previa.

AIM: Severe post-partum hemorrhage during cesarean section due to placenta previa is still one of the leading causes of maternal mortality. The aim of this study was to evaluate the efficiency of intrauterine tamponade with a Sengstaken-Blakemore tube (SB-tube) for the treatment of severe post-partum hemorrhage in cases of placenta previa. MATERIAL AND METHODS: Data were collected from our departmental clinical records on all patients who underwent caesarian section due to placenta previa between 2007 and 2009. RESULTS: During the period analyzed, 37 patients underwent caesarian section due to placenta previa/low-lying placenta. Four (11%) underwent hysterectomy due to placenta accreta and 33 (89%) were treated conservatively. Of the 33 patients with conserved uterus, 10 (28%) patients required a SB-tube during the cesarean section because of continuous post-partum hemorrhage despite appropriate medical treatment. The median bleeding during the operation was 2030±860mL in the patients who used SB-tube. None of them presented severe complications related to these procedures or required any further invasive surgery. CONCLUSION: Intrauterine balloon-tamponade could successfully control severe hemorrhage from a lower uterine segment of a patient with placenta previa. This technique is simple to use, scarcely invasive, and available at a low cost to all maternity wards, and should be considered as one of the first management options to reduce the risk of undesirable hysterectomy.

Aldosterone stimulates the proliferation of uterine leiomyoma cells.

OBJECTIVE: Although uterine leiomyomas are the most common gynaecological benign tumour and greatly affect reproductive health and well being, the pathophysiology and epidemiology of uterine leiomyomas are not well known. Elevated blood pressure has an independent, positive association with risk for clinically detected uterine leiomyomas. Aldosterone is a key biological peptide in the renin-angiotensin-aldosterone system that regulates blood pressure. In this study, we investigated the siginificant stimulatory effect of aldosterone on leiomyoma cells proliferation. STUDY DESIGN: This study investigated the potential role of aldosterone in the proliferation of ELT-3 leiomyoma cells. RESULTS: Aldosterone-induced ELT-3 leiomyoma cell proliferation and the expression of mineralocorticoid receptor (MR) were confirmed. Pre-incubating the cells with the MR blockers spironolactone or eplerenone effectively repressed aldosterone-induced and angiotensin II (Ang II)-induced cell proliferation. Treatment of aldosterone increased the levels of Ang II type-1 receptor mRNA. CONCLUSION: These experimental findings in vitro show the presence of complex regulation of Ang II and aldosterone induced leiomyoma cell proliferation.

A case of complete hydatidiform mole with coexistent fetus: conclusive diagnosis of androgenesis of the molar placenta by variation of paternal acrocentric short arms.

A twin pregnancy consisting of complete hydatidiform mole with coexisting fetus is an extremely rare condition. Recent advances in obstetric ultrasonography and cytogenetic analysis have made the prenatal diagnosis of this rare pregnancy possible. Recent literature advocating DNA polymorphism analysis being required for the accurate diagnosis of complete hydatidiform mole with coexisting fetus is discussed. We present a case of complete hydatidiform mole with coexisting fetus terminated at 16 weeks' gestation. After successful termination of the pregnancy with intravaginal gemeprost, androgenesis of the molar placenta was proven by karyotyping analysis only, without DNA polymorphism analysis, because the short arm of chromosome 21 of the paternal allele had the normal variant satellite. To our knowledge, this is the first case report of complete hydatidiform mole with coexisting fetus diagnosed by variation of the acrocentric short arms, followed by termination with intravaginal gemeprost. We describe the clinical course of our case and review some literature concerning complete hydatidiform mole with coexisting fetus.

Repressive effect of the phytoestrogen genistein on estradiol-induced uterine leiomyoma cell proliferation.

OBJECTIVE: Uterine leiomyomas are the most common gynecological benign tumor and greatly affect reproductive health and well-being. They are the predominant indication for hysterectomy in premenopausal women. Current epidemiological study reported that soy products intake is inversely associated with diseases leading to hysterectomy. Genistein is a soy-derived phytoestrogen and its inhibitory effect on leiomyoma cell proliferation is reported. In this study, we investigated the siginificant inhibitory effect of genistein on estradiol (E(2))-induced leiomyoma cells proliferation. STUDY DESIGN: The Eker rat-derived uterine leiomyoma cell line ELT-3 cells were used. Cell proliferation was assessed by counting the number of cells. The expression of estrogen receptors and peroxisome proliferator-activated receptor-gamma (PPARgamma) was evaluated by Western blot analysis. RESULTS: PPARgamma was expressed in ELT-3 cells and genistein acted as PPARgamma ligand. This inhibitory effect of genistein was attenuated by the treatment of cells with PPARgamma antagonist bisphenol A diglycidyl ether (BADGE) or GW9662. CONCLUSION: These experimental findings in vitro show that the repressive effect of genistein on E(2)-induced ELT-3 cell proliferation is through the activation of PPARgamma. Genistein may be useful as an alternative therapy for leiomyoma.

Up-regulation of alpha5-integrin by E-cadherin loss in hypoxia and its key role in the migration of extravillous trophoblast cells during early implantation.

During early pregnancy, cytotrophoblast cells differentiate into extravillous trophoblast (EVT) cells and invade the uterine spiral arteries. This physiological process is essential for the development of maternal-fetal circulation. Because EVT cells are exposed to a low-oxygen environment during this process, we investigated the role of hypoxia in the mechanism that regulates the invasive behavior of EVT cells. Real-time PCR and immunofluorescent analysis were performed to investigate how hypoxia influences the expression of E-cadherin in villous explants cultures and in trophoblast-derived BeWo cells. We determined that hypoxia induced E-cadherin down-regulation through Snail up-regulation in villous explant cultures. The influence of E-cadherin loss was examined by analyzing the expression of alpha(5)-integrin and phosphorylated focal adhesion kinase (FAK) by Western blot and evaluating trophoblast invasion using a matrigel invasion assay. E-cadherin loss induced the up-regulation of alpha(5)-integrin, which leads to the tyrosine phosphorylation of FAK, resulting in an increase in the invasive activity of EVT cells. An alpha(5)-integrin neutralizing antibody inhibited the invasion of EVT cells by attenuating FAK tyrosine phosphorylation. Immunohistochemical analysis using clinical placental bed biopsies revealed that alpha(5)-integrin was up-regulated and FAK tyrosine phosphorylated (Try(861)) as EVT cells invade the uterine myometrium, whereas E-cadherin expression was down-regulated. These results suggest that alpha(5)-integrin up-regulation induced by E-cadherin loss under hypoxia has a crucial role in regulating the migration of EVT cells. This finding should help us reach a better understanding of the pathogenesis of critical gestational diseases, such as preeclampsia.

Peripheral quantitative computed tomography is useful to monitor response to alendronate therapy in postmenopausal women.

A forearm fracture (Colles' fracture) is often the first sign of osteoporosis and may suggest underlying skeletal fragility. Therefore, establishment of a more accurate and reliable method for the measurement of bone mineral density (BMD) at the distal radius would be beneficial for patients who suffer from osteoporosis. The objective of this study was to evaluate the usefulness of peripheral quantitative computed tomography (pQCT) to monitor the response to alendronate therapy at the distal radius in early postmenopausal Japanese women. Thirty-two early postmenopausal women who were diagnosed with osteoporosis or osteopenia were randomized to either alendronate or control treatment. We analyzed the BMD of the distal radius by pQCT, lumbar spine by dual-energy X-ray absorptiometry (DXA) and the biochemical markers of bone turnover (deoxypyridinoline) at baseline, 3, 6 and 12 months. The control group showed a significant decrease from baseline in the trabecular BMD of the radius at 12 months (3.5 +/- 3.7%; p < 0.01), whereas the alendronate group showed a significant increase (4.3 +/- 8.1%). The changes in the trabecular BMD of the radius between the alendronate and control groups were statistically different at 6 and 12 months (p < 0.01). However, in the total BMD at the diaphysis of the radius, no significant differences were seen in the changes in bone densities between the alendronate and control groups after 1 year of treatment. pQCT detected significant differences in BMD of the radius in early postmenopausal women after 1 year of treatment with alendronate. Collectively, our preliminary clinical trial showed that pQCT might be useful to monitor response to alendronate therapy, especially at the radius, and it might explain why alendronate prevents Colles' fracture.

Metal transcription factor-1 is involved in hypoxia-dependent regulation of placenta growth factor in trophoblast-derived cells.

Placenta growth factor (PlGF) is a placental angiogenic factor. Metal-responsive transcription factor (MTF)-1 was reported to take part in the hypoxic induction of PlGF in RAS-transformed mouse fibroblasts. We contrarily showed that PlGF mRNA and protein levels decreased under hypoxia in a choriocarcinoma BeWo cell line derived from trophoblast. In this report, we examined whether hypoxia-dependent regulation of the PlGF gene in these cells also depends on MTF-1. We analyzed the effect of hypoxia on MTF-1 expression, and it was revealed to be decreased. Moreover, MTF-1 small interfering RNA treatment decreased PlGF mRNA level. To investigate the transcription of PlGF under hypoxia, we cloned promoter region of the human PlGF. Promoter deletion analysis suggested that triple repeats of metal-responsive element located between -511 and -468 bp in the promoter are important for the hypoxic regulation of PlGF. Treatment with MTF-1 small interfering RNA resulted in the significant decreased luciferase activity in PlGF reporter constructs. Chromatin immunoprecipitation showed the binding of the MTF-1 protein to the promoter region. We examined MTF-1 immunoreactivity in trophoblasts of term placental tissue from patients with normal pregnancies and preeclampsia, which represents a condition of placental hypoxia. Immunoreactivity of the MTF-1 protein was decreased in placentas from pregnant women with preeclampsia when compared with those from normal pregnant women. Taken together, these findings suggest that MTF-1 is involved in hypoxia-dependent regulation of PlGF in trophoblast-derived cells.

Relationship between metabolic syndrome and uterine leiomyomas: a case-control study.

BACKGROUND/AIMS: Uterine leiomyomas are the most common gynecological benign tumor and greatly affect reproductive health and well-being. The pathophysiology and epidemiology of fibroids are poorly understood. Obesity and elevated blood pressure have been reported to be predisposing factors. In this study, we investigated whether fibroids are associated with some criteria of the metabolic syndrome. METHODS: The case patients were 213 women who underwent hysterectomy or myomectomy for fibroids, and the control subjects were 159 women who underwent operation for benign indications other than fibroids. Preoperative information on body mass index (BMI), blood pressure (BP), serum triglyceride (TG) and fasting plasma glucose (FPG) was obtained from medical records. The patients were classified as overweight if they had a preoperatively measured BMI of > or =24.0, hypertensive if BP was > or =140/90 mm Hg, hypertriglyceridemic if TG was > or =150 mg/dl, and hyperglycemic if FPG was > or =110 mg/dl. RESULTS: BMI, BP, TG and FPG were significantly higher in the case group compared with the control group. In logistic regression analysis, fibroids were statistically significantly associated with being overweight and hypertensive. With the combination of these risk factors, the risk of fibroids increased. CONCLUSION: Uterine leiomyomas may share pathogenic features with the development of metabolic syndrome.

Dual repressive effect of angiotensin II-type 1 receptor blocker telmisartan on angiotensin II-induced and estradiol-induced uterine leiomyoma cell proliferation.

BACKGROUND: Although uterine leiomyomas or fibroids are the most common gynecological benign tumor and greatly affect reproductive health and well-being, the pathophysiology and epidemiology of uterine leiomyomas are poorly understood. Elevated blood pressure has an independent, positive association with risk for clinically detected uterine leiomyoma. Angiotensin II (Ang II) is a key biological peptide in the renin-angiotensin system that regulates blood pressure. METHODS: In this study, we investigated the potential role of Ang II (1-1000 nM) in the proliferation of rat ELT-3 leiomyoma cells in vitro. RT-PCR and western blot analysis with cell proliferation and DNA transfection assays were performed to determine the mechanism of action of Ang II. RESULTS: Ang II induced ELT-3 leiomyoma cell proliferation (P < 0.01) and the expression of Ang II type 1 receptor (AT(1)R) and AT(2)R mRNA and protein was confirmed. Regarding the intracellular signaling pathway, the Ang II-induced cell proliferation was AT(1)R-, epidermal growth factor receptor-, extracellular-regulated kinase- and protein kinase C-dependent but was not dependent on the AT(2)R or phosphatidylinositol-3 kinase or JAK kinase. The AT(1)R blocker telmisartan, effectively repressed Ang II-induced and estradiol-induced cell proliferation (P < 0.01). AT(1)R, but not AT(2)R, plays a role in Ang II-induced ELT-3 cell proliferation. CONCLUSIONS: These experimental findings in vitro highlight the potential role of Ang II in the proliferation of leiomyoma cells.

Involvement of RelA-associated inhibitor in regulation of trophoblast differentiation via interaction with transcriptional factor specificity protein-1.

Glucose transporter-1 (GLUT1), one of the key functional indicators of placental differentiation, has an important role in placental glucose transport. We previously showed that the protein levels of GLUT1 and nuclear transcription factor specificity protein-1 (Sp1) in rat choriocarcinoma cells (Rcho-1 cells) decreased during the differentiation of these cells to giant cells. We also showed that Sp1 was involved in the regulation of GLUT1 gene expression during this process. RelA-associated inhibitor (RAI) is an inhibitor of nuclear factor-kappaB that was identified by a yeast two-hybrid screen and is preferably expressed in human placenta and heart. RAI was also found to interact with Sp1 and exert an inhibitory effect against the DNA-binding activity of Sp1. We first show here that RAI mRNA expression increased as gestation proceeded and that RAI was localized mainly in the syncytiotrophoblast throughout pregnancy. The chloramphenicol acetyltransferase activity assay in Rcho-1 cells revealed that cotransfection of RAI expression vector resulted in decreased activity of the rat GLUT1 promoter but not in that of a mutated rat GLUT1 promoter lacking the Sp1 binding site. Furthermore, the protein level of RAI increased during differentiation. In addition, transfection of RAI expression vector promoted the morphological differentiation of Rcho-1 cells, and RAI knockdown using RAI-specific small interfering RNA reveals inhibitory effects on the morphological differentiation, as assessed by photomicroscopy. Taken together, these findings suggest that RAI may be involved in the regulation of trophoblast differentiation via interaction with Sp1.