Inhibitory effects of progesterone on plasma membrane fluidity and tumorigenic potential of ovarian epithelial cancer cells

The lethality of common (surface) epithelial ovarian cancer is contingent on its metastatic capacity. Dissemination of the neoplasia throughout the abdominal cavity has been associated with secretion of proteolytic enzymes from vesicles shed by ovarian cancer cells. We report that the lipophilic steroid hormone progesterone decreases the fluid dynamics of plasma membranes of human SKOV-3 adenocarcinoma cells. The decrease in membrane fluidity was related to an inhibition in vitro of exocytotic vesicle release, cellular invasiveness into Matrigel, and colony formation in three-dimensional collagen matrix. Tumorigenesis was suppressed by progesterone in immunocompromised nude mice inoculated intraperitoneally with SKOV-3 cells. Progestins could therefore be of benefit in the prevention and(or) treatment of early-stage ovarian carcinomatosis.     

Transforming growth factor-beta1-dependent activation of Smad2/3 and up-regulation of PAI-1 expression is negatively regulated by Src in SKOV-3 human ovarian cancer cells

The net balance between urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1) has been implicated in tumor cell invasion and metastasis. To elucidate the mechanism of the transforming growth factor-beta1 (TGF-beta1)-dependent up-regulation of PAI-1 expression, we investigated which signaling pathway transduced by TGF-beta1 is responsible for this effect. Here, we show (1) nontoxic concentrations of TGF-beta1 up-regulates uPA expression in HRA and SKOV-3 human ovarian cancer cells, (2) TGF-beta1 activates Smads (phosphorylation of Smad2 and nuclear translocation of Smad3) and subsequently up-regulates PAI-1 expression in HRA cells, whereas TGF-beta1 neither activates Smads nor up-regulates PAI-1 in SKOV-3 cells, (3) pharmacological Src inhibitor PP2 or antisense (AS) c-Src oligodeoxynucleotide (ODN) treatment significantly induces TGF-beta1-dependent activation of Smads, leading to PAI-1 synthesis, compared with controls, in SKOV-3 cells, (4) combination of TGF-beta1 and PP2, which activates PAI-1 expression and reduces uPA expression in SKOV-3, results in decreased invasiveness, (5) pharmacological inhibitors for mitogen-activated protein kinase (MAPK) (PD98059) and phosphoinositide-3-kinase (PI3K) (LY294002 and wortmannin) or AS-PI3K ODN transfection do not affect TGF-beta1-induced Smad signaling and up-regulation of PAI-1 expression in SKOV-3 cells pretreated with PP2, and (6) the induction of PAI-1 protein was partially inhibited by an inhibitor of Sp1-DNA binding, mithramycin, implicating, at least in part, Sp1 in the regulation of this gene by TGF-beta1. In conclusion, TGF-beta1-dependent activation of Smad2/3, leading to PAI-1 synthesis, may be negatively regulated by Src, but not its downstream targets MAPK and PI3K in SKOV-3 cells. These data also reflect the complex biological effect of uPA-PAI-1 system.     

Serum inhibin as an index of ovarian function in women undergoing pituitary suppression and ovarian stimulation in an in vitro fertilization program.

Serum inhibin concentrations, determined by radioimmunoassay, were measured in women undergoing pituitary suppression with buserelin and subsequently ovarian stimulation with human menopausal gonadotropin (hMG). Three types of treatment cycle were investigated, namely (1) cycles showing a normal ovarian response and resulting in a pregnancy; (2) cycles showing a poor response to the hMG, and (3) cycles previously showing a poor ovarian response but augmented with biosynthetic human growth hormone. Good correlations were seen between serum inhibin concentrations and serum progesterone in the luteal phase prior to buserelin (Rs = 0.68), serum oestradiol on the 8th day of hMG administration (Rs = 0.82) or the day of ovulatory trigger (Rs = 0.78), and the number of follicles greater than or equal to 14 mm on the day of ovulatory trigger (Rs = 0.71). These results show inhibin to be a good index of ovarian function in women exhibiting a range of ovarian responses to stimulation in an in vitro fertilization program.     

Hormone response of dairy cows with ovarian cysts after treatment with HCG or GnRH

Twenty lactating Holstein and Guernsey cows, diagnosed by rectal palpation as having ovarian cysts, were randomly divided within breed into two groups to receive either a single intramuscular injection of 100 μg of synthetic gonadotropin releasing hormone (GnRH) or an intravenous injection of 10,000 IU of human chorionic gonadotropin (HCG). The objective was to compare hormonal and clinical changes in cows with ovarian cysts following treatment with GnRH and HCG. Eight of ten and nine of ten cows given either GnRH and HCG, respectively, responded to treatment and subsequent fertility was not different between the two groups. Pre-injection plasma levels of LH, progesterone, and estradiol were highly variable. Mean plasma levels of LH, progesterone and estradiol did not differ between groups either following treatment (days 1–17 post-treatment), at the subsequent estrus, or during days 1–13 following the subsequent estrus. Mean LH levels did not differ significantly on the days either post-treatment or post-estrus except that levels were higher (P < .01) at the subsequent estrus as compared to the other days. Mean progesterone levels increased after treatment with either GnRH or HCG and were higher on days 5, 9 and 13 post-estrus and post-treatment as compared to the subsequent estrus. Mean levels of estradiol were higher (P < .05) at the subsequent estrus than any other time post-treatment or post-estrus. No other days were significantly different. In conclusion, GnRH and HCG are effective treatments for ovarian cysts in cattle. Endocrine response on days following treatment are similar for both compounds.     

Reproductive hormones associated with the ovarian cyst response to GnRH

Eighteen cows with ovarian cysts were administered 100 mug of GnRH and bled prior to treatment, at half hour intervals for 4 hours posttreatment and on days 1, 5 and 9 posttreatment. Blood plasma was analyzed for estradiol-17beta, progesterone and LH by radioimmunoassay. Response to treatment was recorded as positive if ovulation was detected within 30 days posttreatment. Fourteen cows (78%) initiated ovarian cycles by 30 days posttreatment. Mean pretreatment concentrations of estradiol-17beta, progesterone and LH and the GnRH induced LH release were not different for positive or no response cows. However, all seven cows that had pretreatment progesterone concentrations greater than 1.0 ng/ml had a positive response to treatment. Eight of the remaining eleven cows had a progesterone response (mean progesterone concentrations on days 5 and 9 posttreatment) greater than 1.0 ng/ml; seven had a positive response to treatment. In summary, most cows with ovarian cysts administered GnRH will initiate ovarian cycles within 30 days if: 1) pretreatment progesterone concentrations are greater than 1.0 ng/ml or 2) if progesterone response is greater than 1.0 ng/ml.     

Endocrine response of postpartum anestrous beef cows to GnRH or PMSG

Forty-one postpartum anestrous Hereford cows, maintained under range conditions, were used to determine the influence of gonadotropin releasing hormone (GnRH) or pregnant mare serum gonadotropin (PMSG) on ovarian function. Anestrous cows were identified by estrous detection with sterile bulls and concentrations of progesterone in plasma obtained weekly. At 45 +/- 2 days postpartum, cows were allotted to the following treatments: (1) control (saline), (2) 100 mug GnRH, (3) 200 mug GnRH, (4) 200 mug GnRH in carboxymethyl cellulose (CMC), (5) 500 IU PMSG, (6) 1,000 IU PMSG or (7) 2,000 IU PMSG. Cows were bled frequently the first day after treatment and then every other day until 85 days postpartum. The LH responses after 100 and 200 mug of GnRH were not significantly different and mixing 200 mug GnRH with CMC before injection did not significantly alter the LH response. During the first 20 days after treatment, neither GnRH nor 500 IU PMSG altered estradiol concentrations in plasma, but treatment of cows with 1,000 or 2,000 IU PMSG resulted in increased (P<0.01) concentrations of estradiol. The time postpartum required for concentrations of progesterone in plasma to exceed 1 ng/ml was reduced (P<0.05) by all treatments except 100 mug GnRH. These data indicate that GnRH causes LH release in anestrous range cows and that treatment with 1,000 or 2,000 IU PMSG initiates ovarian activity as evidenced by increased concentrations of estradiol in plasma.     

The effect of method of administration on ovarian responses of seasonally anestrous ewes administered gonadotrophin releasing hormone

Mature ewes were treated during the anestrous season with saline (I) or GnRH either intramuscularly in saline (II), subcutaneously in carboxymethylcellulose (CMC) (III) or subcutaneously in gelatin capsules (IV). Fifty μg of GnRH or 1 ml of saline were administered to 22 ewes in experiment 1. In experiments 2 and 3, forty-seven and 10 ewes received 250 μg GnRH or 1 ml of saline. Ewes were bled for progesterone determination prior to treatment and up to 12 or 13 days after treatment. In experiment 3, ovaries were observed via mid-ventral laparotomy 4 days after treatment and ovarian structures recorded. Ewes were classified into one of four progesterone response categories: cyclic, transient, prolonged or no response. The only treatment that changed the progesterone response from the saline-treated controls was GnRH in gelatin capsules. More ewes in this group were classified with a prolonged progesterone response (40%) than in the saline control group (0%). GnRH (in gelatin capsules)-treated ewes in the prolonged progesterone response category had higher concentrations of plasma progesterone than GnRH (in saline or CMC)-treated ewes with a prolonged progesterone response. For the GnRH (in gelatin capsule)-treated ewes, the prolonged progesterone response was similar to progesterone in ewes during the estrous cycle and all ewes in the prolonged progesterone category had corpora lutea (experiment 3). In summary, implanting the GnRH in gelatin capsules subcutaneously in seasonally anestrous ewes increased the ovulation response and enhanced corpus luteum function over ewes administered GnRH in saline intramuscularly.     

Paclitaxel Resistance and Multicellular Spheroid Formation Are Induced by Kallikrein-Related Peptidase 4 in Serous Ovarian Cancer Cells in an Ascites Mimicking Microenvironment

High tumor kallikrein-related-peptidase 4 (KLK4) levels are associated with a poor outcome for women with serous epithelial ovarian cancer (EOC), for which peritoneal dissemination and chemoresistance are key events. To determine the role of KLK4 in these events, we examined KLK4-transfected SKOV-3 and endogenous KLK4 expressing OVCA432 cells in 3-dimensional (3D) suspension culture to mimic the ascites microenvironment. KLK4-SKOV-3 cells formed multicellular aggregates (MCAs) as seen in ascites, as did SKOV-3 cells treated with active KLK4. MCA formation was reduced by treatment with a KLK4 blocking antibody or the selective active site KLK4 sunflower trypsin inhibitor (SFTI-FCQR). KLK4-MCAs formed larger cancer cell foci in mesothelial cell monolayers than those formed by vector and native SKOV-3 cells, suggesting KLK4-MCAs are highly invasive in the peritoneal microenvironment. A high level of KLK4 is expressed by ascitic EOC cells compared to matched primary tumor cells, further supporting its role in the ascitic microenvironment. Interestingly, KLK4 transfected SKOV-3 cells expressed high levels of the KLK4 substrate, urokinase plasminogen activator (uPA), particularly in 3D-suspension, and high levels of both KLK4 and uPA were observed in patient cells taken from ascites. Importantly, the KLK4-MCAs were paclitaxel resistant which was reversed by SFTI-FCQR and to a lesser degree by the general serine protease inhibitor, Aprotinin, suggesting that in addition to uPA, other as yet unidentified substrates of KLK4 must be involved. Nonetheless, these data suggest that KLK4 inhibition, in conjunction with paclitaxel, may improve the outcome for women with serous epithelial ovarian cancer and high KLK4 levels in their tumors.     

Tumor disposition of pegylated liposomal CKD-602 and the reticuloendothelial system in preclinical tumor models

Liposomes, such as pegylated-liposomal CKD-602 (S-CKD602), undergo catabolism by macrophages and dendritic cells (DCs) of the reticuloendothelial system (RES). The relationship between plasma and tumor disposition of S-CKD602 and RES was evaluated in mice bearing A375 melanoma or SKOV-3 ovarian xenografts. Area under the concentration-time curves (AUCs) of liposomal encapsulated, released, and sum total (encapsulated + released) CKD-602 in plasma, tumor, and tumor extracellular fluid (ECF) were estimated. A375 and SKOV-3 tumors were stained with cd11b and cd11c antibodies as measures of macrophages and DC. The plasma disposition of S-CKD602 was similar in both xenograft models. The ratio of tumor sum total AUC to plasma sum total AUC was 1.7-fold higher in mice bearing human SKOV-3 xenografts, compared with A375. The ratio of tumor ECF AUC to tumor sum total AUC was 2-fold higher in mice bearing human SKOV-3 xenografts, compared with A375. The staining of cd11c was 4.5-fold higher in SKOV-3, compared with A375 (P?<?0.0001). The increased tumor delivery and release of CKD-602 from S-CKD602 in the ovarian xenografts, compared with the melanoma xenografts, was consistent with increased cd11c staining, suggesting that variability in the RES may affect the tumor disposition of liposomal agents.     

Influence of immunization against GnRH on reproductive cyclicity and estrous behavior in the mare

The aim of this study was to evaluate the effect of active immunization against GnRH on ovarian activity, plasma progesterone and estradiol concentrations and on estrous behavior in adult mares. Eighteen cyclic mares were randomly divided into a treatment and control group. Nine mares were immunized twice with 2 mL (400 microg GnRH-protein conjugate) of a GnRH-vaccine (Improvac, CSL Limited, Australia) administered intramuscularly, 4 weeks apart. Control mares received the same amount of saline solution. Ovaries and uterus of all mares were examined weekly by ultrasonography from 3 weeks before to 60 weeks after first immunization. Thereafter, vaccinated mares were evaluated monthly until 100 weeks after first vaccination. In addition, mares were teased with a stallion for assessment of estrous behavior and blood was collected for progesterone, estradiol-17beta and GnRH antibody titer determination. Results demonstrate that vaccination against GnRH significantly (P<0.05) influenced all parameters, except estradiol-17beta concentration. All vaccinated mares ceased reproductive cyclicity (plasma progesterone <1 ng/mL, follicles <3 cm) within 8 weeks after the first injection and ovarian activity remained suppressed for a minimum of 23 weeks. Five mares resumed cyclicity (follicles >3 cm, progesterone >1 ng/mL) while three mares showed only follicular activity (follicles >3 cm) and one mare remained completely suppressed for the entire duration of the study. In spite of ovarian suppression, four mares expressed sporadic and one mare continuous estrous behavior. In conclusion, reproductive cyclicity in adult mares can be successfully suppressed by immunization against GnRH but the timing of resumption of cyclicity is highly variable and estrous behavior may occur in spite of ovarian suppression.     

Urinary steroid evaluations to monitor ovarian function in exotic ungulates: VIII. Correspondence of urinary and plasma steroids in the llama (Lama glama) during nonconceptive and conceptive cycles

Ovarian function was evaluated in mature female llamas (n = 2) during seven ovulations in 2 conceptive and 5 nonconceptive ovarian cycles by measuring urinary and plasma hormone concentrations. Ovulation was induced by three different methods; administration of gonadotropin-releasing hormone (GnRH), copulation with a vasectomized male and copulation with an intact male. Plasma estradiol and progesterone concentrations, and urinary concentrations of estrogen conjugates and two progesterone metabolites, pregnanediol-3-glucuronide (PdG), and immunoreactive (iPdG), concentrations were compared to determine their value in monitoring ovarian function. Estrogen concentrations in urine corresponded to estradiol levels in plasma and accurately reflected changes in follicular activity when evaluated over several daily samples. Plasma progesterone and urinary iPdG were reliable indicators of luteal function. These data represent the first comparison of blood and urinary hormone measurements for monitoring the complete ovarian cycle of an ungulate, and demonstrates that either can be used to assess changes in ovarian activity in this species.     

Action of gonadotropin-releasing hormone II on the baboon ovary

The content, binding affinity, and bioactivity of chicken II GnRH (GnRH II) and a stable analogue of GnRH II (GnRH II analogue) in the baboon ovary were studied. Although mammalian GnRH is rapidly degraded by baboon ovarian extracts, we designed a GnRH II analogue that is stable to ovarian enzymatic degradation. This analogue binds to the ovarian membranes with high affinity (41 +/- 3 nM), having 20-fold the affinity of a potent mammalian GnRH analogue. The bioactivity of GnRH II and this GnRH II analogue on the regulation of ovarian progesterone release was compared with that for a potent mammalian GnRH analogue using a baboon granulosa cell culture system. Both GnRH II and GnRH II analogue produced significant inhibition of progesterone release from the granulosa cells (P < 0.03 and P < 0.005, respectively), with a greater reduction observed using the GnRH II analogue. After 24 h in culture, this GnRH II analogue produced a 59% +/- 5% inhibition of progesterone with a concentration as low as 1 nM. Maximal inhibition of 75% +/- 1% was attained with 10 nM GnRH II analogue. The endogenous GnRH II content in the baboon ovary was 5-14 pmoles/g protein. The release of endogenous GnRH II from granulosa cells was observed throughout the 48 h in culture. These studies demonstrated the presence of high enzymatic activity for the degradation of mammalian GnRH in the ovary, whereas this GnRH II analogue was stable. High-affinity binding sites for this GnRH II analogue were also found. GnRH II and this GnRH II analogue can regulate progesterone production from baboon granulosa cells, suggesting that GnRH II is a potent regulator of ovarian function.     

Effect of histone H2A on progesterone production by bovine luteal cells

Histone H2A competitively inhibits binding of GnRH to high affinity rat ovarian receptor sites and blocks gonadotropin-stimulated steroid and cAMP accumulation during culture of rat granulosal or luteal cells. The objective of our study was to examine the progesterone suppressive effects of histone H2A on bovine luteal cells. In the first study, luteal cells were treated at Time = 0 h with a partially purified preparation of bovine ovarian histone H2A (3 ng GnRH equivalents, 800 micrograms protein), equivalent amounts of GnRH (3 ng), or BSA (800 micrograms) and incubated for a total of 4 h. At Time = 2 h, cells were treated with 5 ng bovine LH (bLH) or with medium. Histone H2A completely blocked both basal and LH-induced accumulation of progesterone compared with untreated cultures or cultures treated with bLH. Neither BSA nor GnRH suppressed LH-induced progesterone accumulation. In the second study, histone H2A was added to cultures at Time = 0 h and bovine luteal cells were cultured for 8 h. After 2 h of treatment, histone H2A (3 ng GnRH equivalents) was removed from selected cultures and replaced with fresh medium. Four hours later cultures were treated with 5 ng bLH or medium. LH treatment of cultures from which histone H2A had been removed resulted in an increase in accumulation of progesterone compared with control cultures treated throughout the treatment period with histone H2A. The third study examined the effect of 9-181 pg GnRH equivalents (1.7-34 micrograms protein) of a highly purified preparation of bovine ovarian histone H2A on basal and LH-induced progesterone production during 2 or 3 h of culture.(ABSTRACT TRUNCATED AT 400 WORDS)     

Differential effects of cellular fibronectin and plasma fibronectin on ovarian cancer cell adhesion, migration, and invasion

Summary The main form of fibronectin (FN) encountered by tumor cells in vivo is cellular FN (cFN), which differs structurally and functionally from the commonly used plasma FN (pFN). We compared the effects of cFN and pFN on the ovarian carcinoma lines OVCAR-3 and SKOV-3 and on cultures of normal ovarian surface epithelium, which is the precursor of the epithelial ovarian carcinomas. Ovarian surface epithelial cells and SKOV-3 cells attached and spread faster on cFN than on pFN. On cFN, SKOV-3 migration was enhanced compared with pFN or plastic. In a matrigel transfilter assay, cFN strongly inhibited SKOV-3 invasion, whereas pFN did not. In contrast to SKOV-3, OVCAR-3 cells adhered faster on FN than on plastic but did not discriminate between cFN and pFN, and they did not migrate or invade matrigel either with or without FN. In both carcinoma lines, proliferation was unaffected by either FN. The results show profound differences in the responses to cFN and pFN by two invasive ovarian carcinoma lines. Because cFN is the main type that cancer cells encounter in vivo, extrapolations from culture data to in vivo events should preferably be based on studies using this form of FN.     

Expression and roles of Slit/Robo in human ovarian cancer

The Slit glycoproteins and their Roundabout (Robo) receptors regulate migration and growth of many types of cells including human cancer cells. However, little is known about the expression and roles of Slit/Robo in human ovarian cancer. Herein, we examined the expression of Slit/Robo in human normal and malignant ovarian tissues and its potential participation in regulating migration and proliferation of human ovarian cancer cells using two ovarian cancer cell lines, OVCAR-3 and SKOV-3. We demonstrated that Slit2/3 and Robo1 were immunolocalized primarily in stromal cells in human normal ovaries and in cancer cells in many histotypes of ovarian cancer tissues. Protein expression of Slit2/3 and Robo1/4 was also identified in OVCAR-3 and SKOV-3 cells. However, recombinant human Slit2 did not significantly affect SKOV-3 cell migration, and OVCAR-3 and SKOV-3 cell proliferation. Slit2 also did not induce ERK1/2 and AKT1 phosphorylation in OVCAR-3 and SKOV-3 cells. The current findings indicate that three major members (Slit2/3 and Robo1) of Slit/Robo family are widely expressed in the human normal and malignant ovarian tissues and in OVCAR-3 and SKOV-3 cells. However, Slit/Robo signaling may not play an important role in regulating human ovarian cancer cell proliferation and migration.     

Induced ovulation and changes in pituitary responsiveness to continuous infusion of gonadotropin-releasing hormone during the ovarian cycle in the bullfrog, Rana catesbeiana

Chronic (2-4 days) constant-rate infusions of mammalian gonadotropin releasing hormone (GnRH) were performed in female bullfrogs, Rana catesbeiana. The magnitude and temporal relationship of profiles of plasma follicle-stimulating hormone (FSH), luteinizing hormone (LH) and sex steroids [testosterone (T), estradiol-17 beta (E2) and progesterone (P)] during GnRH infusion were dependent on ovarian stage. However, in all females, the same biphasic increase in plasma gonadotropins was apparent and initial elevations in gonadotropins were accompanied by correlated increments in plasma T and E2. Complete pituitary "desensitization" to chronic GnRH infusion was not observed. Females in early follicular stages were relatively unresponsive to infusions of 1.0-10.0 micrograms/h GnRH; elevations in plasma LH were marginal and FSH was unchanged. Females with fully developed (preovulatory) ovaries were more responsive: infusion of 1.0 micrograms/h GnRH produced significant elevations in plasma LH by 2 h followed by even larger increases ("surges") after 12 h. This LH "surge" was preceded by a decline in plasma T and E2 and was accompanied by abrupt elevations in plasma P and by ovulation. Postovulatory females showed a more gradual and smaller increase in plasma LH. Infusion of GnRH in the female bullfrog establishes a clear relationship between pituitary responsiveness and the ovarian cycle not evident from acute GnRH injection; GnRH was most effective immediately before ovulation. These data are also the first to detail periovulatory changes in plasma gonadotropins and ovarian steroids in an amphibian.     

Oestradiol inhibits spontaneous and cisplatin-induced apoptosis in epithelial ovarian cancer cells: relationship to DNA repair capacity

A prospective role of sex steroid hormones in the pathogenesis of common epithelial ovarian cancer remains equivocal. We hypothesized that oestradiol can protect ovarian cells from apoptosis by augmenting their DNA repair capacity. Two established oestrogen receptor-positive human cancer cell lines of ovarian surface epithelial origin (OVCAR-3, SKOV-3) were studied during short-term (24 h) subculture in the absence or presence of oestradiol-17β and/or the DNA-damaging chemotherapeutic agent cisplatin. Apoptosis was monitored among individual cells by in situ DNA fragmentation analysis. Basal rates of apoptosis were diminished by exposure to oestradiol (progesterone or testosterone were without effect). Oestradiol also suppressed apoptosis induced by cisplatin and enhanced the repair of a cisplatin-damaged reporter chloramphenicol-O-acetyltransferase gene transfected into ovarian cells. The ability of oestrogen-responsive ovarian cancer cells to efficiently repair DNA and thereby avoid apoptosis may be related to propensity for clonal expansion and drug resistance. This revised version was published online in November 2006 with corrections to the Cover Date.     

Chk1反义寡核苷酸联合顺铂抑制卵巢癌侵袭转移的分子机制

目的:探究Chk1反义寡核苷酸(CHK1-ASODN)单独或联合顺铂(DDP)对卵巢癌细胞系SKOV-3侵袭转移能力的影响,并阐明其可能的分子机制。方法:体外培养人卵巢癌细胞系SKOV-3,CHK1-ASODN单独或联合DDP处理48 h后,划痕实验检测细胞迁移能力;Transwell实验检测细胞侵袭能力;显微镜下观察细胞上皮或间质表型特征;Western blot及实时定量PCR技术分别检测上皮间质转化(EMT)特异性标志物(E-cadherin、N-cadherin)以及EMT关键调控分子ZEB1的蛋白及m RNA的表达水平。结果:与对照组相比较,CHK1-ASODN单独或联合DDP均能显著抑制SKOV-3细胞的迁移及侵袭(P0.05);细胞表现为间质化表型;E-cadherin的表达显著升高(P0.05),而N-cadherin的表达则显著降低(P0.05);ZEB1的表达显著降低(P0.05)。结论:CHK1-ASODN单独或联合DDP下调ZEB1的表达进而逆转EMT可能是其抑制卵巢癌侵袭转移的重要机制之一。     

Gonadotropin-releasing hormone (GnRH) inhibits ovulation induced with luteinizing hormone (LH) in proestrous hypophysectomized rats

In this paper we present evidence that a single low dose of the natural synthetic gonadotropin-releasing hormone (GnRH), inhibits ovulation induced by LH in proestrous-hypophysectomized rats. Rats hypophysectomized by the parapharyngeal route in the morning of proestrus received an intravenous injection of 100 or 300 ng GnRH at 1400 h immediately followed by 1.0 microgram LH per 100 g bw. In control groups, either one or both hormones were replaced with 0.9% NaCl. Ovulation was assessed the following morning by counting the ova present in oviductal flushings. All the rats treated with LH alone ovulated, and the addition of GnRH reduced significantly the number of ovulating rats and the number of ova per ovulating rat. In other groups of rats hypophysectomized in the morning of proestrus and treated in the same way, ovarian or adrenal secretory rates of estradiol and/or progesterone were measured after cannulation of the corresponding vein, in the afternoon of proestrus. In these animals, GnRH failed to inhibit either the ovarian progesterone surge observed 2 h after LH administration, or the adrenal progesterone secretion. All hypophysectomized rats showed lower ovarian secretory rate of estradiol than intact rats; this rate was not affected by treatment with LH or LH plus GnRH. The systemic estradiol levels in plasma of hypophysectomized rats were distributed within a range of 20 pg/ml to 50 pg/ml. The number of rats whose levels were above 21 pg/ml on estrus day was significantly higher in rats receiving 300 ng GnRH as compared to those receiving 100 ng GnRH, reaching values that surpassed the concentration found in intact, untreated animals at the same time of estrus. This effect did not depend on LH administration.     

Chronic treatment with an agonist of gonadotropin-releasing hormone enhances luteal function in cattle

Our hypothesis was that luteal function, as determined by plasma progesterone concentrations, and corpus luteum (CL) size is enhanced in cattle administered an agonist of GnRH when the CL is developing as compared with administration of an agonist when the CL is fully functional. Cattle were chronically administered a GnRH agonist, azagly-nafarelin, from Day 3 to Day 21 (D3) or Day 12 to Day 21 (D12) or served as untreated control females (Day 0 = behavioral estrus). Blood samples were serially collected on Days 7 and 14 to evaluate LH secretory patterns and twice daily to measure plasma progesterone. Ultrasonographic examinations were conducted daily to record the area of the CL. CL size and plasma progesterone concentrations were both enhanced in the D3 group as compared with the control group. Progesterone was increased in the D12 group on Days 16 and 17 as compared with the control females. Treatment with GnRH agonist increased basal and mean LH concentrations in both D3 and D12 groups as compared with the controls. We rejected our hypothesis because chronic administration of a GnRH agonist increased plasma progesterone when administered both when the CL was developing and when it was fully functional. The enhanced luteal function was likely due to increased basal LH.