Ken-ichirou Morishige

RhoA/Rho-Kinase Cascade Is Involved in Oxytocin-Induced Rat Uterine Contraction

The RhoA/Rho-kinase cascade is involved in various cellular functions, including migration, proliferation, and smooth muscle contraction. We examined the potential role of this pathway in oxytocin-induced uterine contraction. The specific Rho-kinase inhibitor Y-27632 inhibited oxytocin-induced rat uterine contraction on d 21 of pregnancy in a concentration-dependent manner, whereas the extent of this inhibition was reduced in the nonpregnant uterus. Y-27632 had no effect on oxytocin-induced intracellular Ca 2 mobilization in myometrial cells. Immunoblot analysis showed that oxytocin increased the level of myosin light chain phosphorylation, and this increase was attenuated by Y-27632. Oxytocin increased the phosphorylation of myosin-binding subunit of myosin phosphatase, one of the major substrates of Rho-kinase, and this increase was reduced by Y-27632. The expression of Rhokinase protein was shown to increase in the uterus during pregnancy compared with the nonpregnant uterus, whereas the expression of RhoA protein remained at the same level during pregnancy. RT-PCR and Northern blot analysis showed that the expression of Rho-kinase was up-regulated at the transcriptional level during pregnancy. These results suggest that the RhoA/Rho-kinase pathway may have an important role in oxytocin-induced uterine contraction, and that up-regulation of Rho-kinase is involved in the mechanism underlying the increased contractility of the pregnant myometrium. (Endocrinology 143: 920 –929, 2002)

Differential distribution of classical inwardly rectifying potassium channel mRNAs in the brain: comparison of IRK2 with IRK1 and IRK3.

Distribution of IRK2 inwardly rectifying potassium channel mRNA in the mouse brain was studied using in situ hybridization histochemistry and compared with those of other classical inwardly rectifying potassium channel (IRK1 and IRK3) mRNAs. All these IRK channel mRNAs were detected in neurons, but not in glial cells. Their distribution patterns in the brain were, however, quite divergent: IRK2 mRNA was detected extremely high in granule cells of cerebellum, relatively high in motor trigeminal nucleus and moderate in olfactory bulb, piriform cortex, cerebral cortex, CA1 through CA3 regions of hippocampus, dentate gyrus and pontine nucleus. On the other hand, IRK1 mRNA was expressed throughout whole brain but in particular subsets of neurons, and IRK3 mRNA was in forebrain. Expression of these three IRK mRNAs overlapped in hippocampus, olfactory bulb, and cerebral cortex. This differential distribution of IRK mRNAs suggests that each of these channels has its specific function in regulation of the excitability of brain neurons.

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.

Cancer stem-like cells of ovarian clear cell carcinoma are enriched in the ALDH-high population associated with an accelerated scavenging system in reactive oxygen species

OBJECTIVEnIn ovarian cancer cases, recurrence after chemotherapy is frequently observed, suggesting the involvement of ovarian cancer stem-like cells (CSCs). The chemoresistance of ovarian clear cell carcinomas is particularly strong in comparison to other epithelial ovarian cancer subtypes. We investigated the relationship between a CSC marker, aldehyde dehydrogenase 1 (ALDH1), and clinical prognosis using ovarian clear cell carcinoma tissue samples. Furthermore, we investigated the antioxidant mechanism by which CSCs maintain a lower reactive oxygen species (ROS) level, which provides protection from chemotherapeutic agents.nnnMETHODSnImmunohistochemical staining was performed to examine the CSC markers (CD133, CD44, ALDH1) using ovarian clear cell carcinoma tissue samples (n=81). Clear cell carcinoma cell lines (KOC-7C, OVTOKO) are separated into the ALDH-high and ALDH-low populations by ALDEFLUOR assay and fluorescence-activated cell sorting (FACS). We compared the intracellular ROS level, mRNA level of the antioxidant enzymes and Nrf2 expression of the two populations.nnnRESULTSnHigh ALDH1 expression levels are related to advanced stage in clear cell carcinoma cases. ALDH1 expression significantly reduced progression free survival. Other markers are not related to clinical stage and prognosis. ALDH-high cells contained a lower ROS level than ALDH-low cells. Antioxidant enzymes were upregulated in ALDH-high cells. ALDH-high cells showed increased expression of Nrf2, a key transcriptional factor of the antioxidant system.nnnCONCLUSIONSnALDH-positive CSCs might have increased Nrf2-induced antioxidant scavengers, which lower ROS level relevant to chemoresistance in ovarian clear cell carcinoma.

Up-Regulation of α5-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.

Postoperative concurrent nedaplatin-based chemoradiotherapy improves survival in early-stage cervical cancer patients with adverse risk factors

OBJECTIVESnThe aim of this study was to evaluate the efficacy of postoperative nedaplatin-based concurrent chemoradiotherapy (CCRT) in patients with FIGO stage IA2-IIB cervical cancer with adverse risk factors.nnnMETHODSnWe retrospectively reviewed the medical records of 183 patients with early-stage cervical cancer who had undergone radical surgery between April 1997 and March 2006. Of these, 68 patients displayed high-risk prognostic factors such as positive pelvic lymph nodes, parametrial involvement, or a positive surgical margin. Fifty-seven patients demonstrated intermediate-risk prognostic factors including deep stromal invasion, capillary lymphatic space involvement, or large tumor diameter. These patients were treated postoperatively with CCRT or radiotherapy alone (RT). Fifty-eight patients showed no risk factors and, therefore, received no adjuvant therapy after surgery. The 3-year recurrence rate, progression free survival (PFS), and overall survival (OS) were compared between the treatment groups.nnnRESULTSnCCRT was significantly superior to RT alone with regard to recurrence rate, PFS, and OS in patients that displayed high-risk and intermediate-risk prognostic factors. The frequencies of acute grade 3-4 toxicities were significantly higher in patients treated with CCRT than in those treated with RT alone. However, no statistically significant difference was observed with regard to severe late toxicities.nnnCONCLUSIONSnPostoperative nedaplatin-based CCRT was safely performed and improved the prognosis of FIGO stage IA2-IIB cervical cancer patients displaying high-risk or intermediate-risk prognostic factors. This treatment can be considered as an alternative to cisplatin-based chemoradiotherapy in this patient population.

Integrin Inhibitors as a Therapeutic Agent for Ovarian Cancer

Ovarian cancer is a deadly disease, with a cure rate of only 30%. Despite aggressive treatments, relapse remains almost inevitable in patients with advanced-stage disease. In recent years, great progress has been made towards targeting integrins in cancer treatment, and clinical studies with various integrin inhibitors have demonstrated their effectiveness in blocking cancer progression. Given that the initial critical step of ovarian cancer metastasis is the attachment of cancer cells onto the peritoneum or omentum, in addition to the proven positive clinical results of anti-angiogenic therapy, targeting integrins is likely to be one of the most feasible approaches. This paper summarizes the current understanding of the integrin biology in ovarian cancer metastasis and the various therapeutic approaches attempted with integrin inhibitors. Although no integrin inhibitors have shown favorable results so far, integrin-targeted therapies continue to be a promising approach to be explored for further clinical investigation.

Postpartum hemorrhage in coagulopathic patients: preliminary experience with uterine arterial embolization with N-butyl cyanoacrylate.

The present report describes uterine artery embolization (UAE) with N-butyl cyanoacrylate (NBCA) in four patients with postpartum hemorrhage (PPH) in a coagulopathic condition. Initial UAE with gelatin sponge particles and/or fibered platinum microcoils had failed in these patients. Subsequently, a mixture of NBCA and iodinated poppy seed oil (Lipiodol) was used as embolic material, and hemostasis was achieved immediately in all patients. No vaginal bleeding recurred thereafter, and all patients were discharged within 3 weeks of UAE. One patient resumed menstruation in 6 months. NBCA may be a promising embolic material for emergent UAE in patients with PH, especially for patients with a coagulopathic condition.

Postoperative whole pelvic radiotherapy plus concurrent chemotherapy versus extended-field irradiation for early-stage cervical cancer patients with multiple pelvic lymph node metastases

OBJECTIVESnThe aim of this study was to compare the efficacy of postoperative pelvic radiotherapy plus concurrent chemotherapy with that of extended-field irradiation (EFRT) in patients with FIGO Stage IA2-IIb cervical cancer with multiple pelvic lymph node metastases.nnnMETHODSnWe retrospectively reviewed the medical records of patients with FIGO Stage IA2-IIb cervical cancer who had undergone radical surgery between April 1997 and March 2008. Of these, 55 patients who demonstrated multiple pelvic lymph node metastases were treated postoperatively with pelvic radiotherapy plus concurrent chemotherapy (n=29) or EFRT (n=26). Thirty-six patients with single pelvic node metastasis were also treated postoperatively with pelvic radiotherapy plus concurrent chemotherapy. The recurrence rate, progression free survival (PFS), and overall survival (OS) were compared between the treatment groups.nnnRESULTSnPelvic radiotherapy plus concurrent chemotherapy was significantly superior to EFRT with regard to recurrence rate (37.9% vs 69.2%, p=0.0306), PFS (log-rank, p=0.0236), and OS (log-rank, p=0.0279). When the patients were treated with pelvic radiotherapy plus concurrent chemotherapy, there was no significant difference in PFS or OS between the patients with multiple lymph node metastases and those with single node metastases. With regards to grade 3-4 acute or late toxicities, no statistically significant difference was observed between the two treatment groups.nnnCONCLUSIONSnPostoperative pelvic radiotherapy plus concurrent chemotherapy is superior to EFRT for treating patients with FIGO Stage IA2-IIb cervical cancer displaying multiple pelvic lymph node metastases.

Expression of Epidermal Growth Factor and Transforming Growth Factor-Alpha in Fallopian Tube Epithelium and Their Role in Embryogenesis

We studied the expression of epidermal growth factor (EGF) and transforming growth factor (TGF)-alpha in human fallopian tube epithelium at various menstrual stages. Immunohistochemical staining using anti-EGF and anti-TGF-alpha antibodies showed a specific staining in ampullary tube epithelium at late follicular and luteal stages but the staining was very weak at the early follicular stage. Quantitative reverse transcription and polymerase chain reaction (RT-PCR) using beta-actin mRNA as an internal standard revealed the menstrual-stage-specific expression of EGF and TGF-alpha gene transcripts: amounts of EGF and TGF-alpha mRNA relative to those of beta-actin were significantly higher at late follicular and luteal stages than at the early follicular stage. To clarify the biological role of these growth factors, mouse 2-cell embryos were cocultured with human fallopian tube epithelial cells with or without blocking the action of these growth factors. Cocultures significantly promoted blastocyst formation, but this promotive effect of the tubal epithelial cells was completely abolished by the addition of anti-EGF and/or anti-TGF-alpha monoclonal neutralizing antibodies to the coculture system. These results demonstrated that EGF and TGF-alpha were synthesized and expressed in fallopian tube epithelium at specific menstrual stages, and may be involved in early embryonic development.