Keratinocyte growth factor and its receptor in the rhesus macaque placenta during the course of gestation

PLAC1 is essential for FGF7/FGFRIIIb-induced Akt-mediated cancer cell proliferation

PLAC1 (placenta enriched 1) is a mammalian trophoblast-specific protein. Aberrant expression of PLAC1 is observed in various human cancers, where it is involved in the motility, migration, and invasion of tumor cells, which are associated with the phosphoinositide 3-kinase (PI3K)/AKT pathway. We previously demonstrated that AKT activation mediates the downstream effects of PLAC1; however, the molecular mechanisms of PLAC1-induced AKT-mediated tumor-related processes are unclear. We studied human choriocarcinoma and breast cancer cell lines to explore the localization and receptor-ligand interactions, as well as the downstream effects of PLAC1. We show secretion and adherence of PLAC1 to the extracellular matrix, where it forms a trimeric complex with fibroblast growth factor 7 (FGF7) and its receptor, FGF receptor 2 IIIb (FGFR2IIIb). We further show that PLAC1 signaling via FGFR2IIIb activates AKT phosphorylation in cancer cell lines. As the FGF pathway is of major interest in anticancer therapeutic strategies, these data further promote PLAC1 as a promising anticancer drug target.

Transcervical administration of polidocanol foam prevents pregnancy in female baboons

Background

Our objective was to conduct a pilot study to determine if transcervical administration of polidocanol foam (PF) with or without doxycycline or benzalkonium chloride (BZK) would prevent pregnancy in baboons.

Methods

In study phase 1, adult cycling baboons underwent a hysterosalpingogram to evaluate tubal patency prior to transcervical infusion of 20 mL of 5% PF followed by 1 mL of saline containing 100 mg doxycycline (5%/doxy; n=5), 3% PF plus doxycycline (3%/doxy; n=4), 3% PF with 0.01% BZK (3%/BZK; n=4) or no additional treatment (control; n=9). Immediately following treatment, animals received intramuscular depot medroxyprogesterone acetate (DMPA, 2 mg/kg) to suppress cyclicity during healing and were then socially housed with males of proven fertility. The primary outcome was pregnancy within six cycles of resumption of menses (efficacy phase 1). During study phase 2, PF-treated females from study phase 1 contributed additional cycles (6–8) of exposure (efficacy phase 2), and 5 control females who had recovered from medical abortion (after study phase 1 pregnancy) were subsequently treated with 5% PF (with DMPA) and exposed to breeding (efficacy phase 1; n=3 six cycles, n=2 five cycles).

Results

All females resumed normal menstrual cycles and mating activity after DMPA. During efficacy phase 1, 7/9 (78%) control females became pregnant. In contrast, fewer pregnancies occurred in PF-treated females: 5% PF 0/5 (0%), 5%/doxy 1/5 (20%), 3%/doxy 1/4 (25%) and 3%/BZK 1/4 (25%). During efficacy phase 2, only one additional pregnancy occurred (3%/BZK).

Conclusions

A single transcervical treatment with 5% PF prevented pregnancy in most baboons. Cotreatment with doxycycline or BZK did not improve results.

Implications

Transcervical intrauterine administration of PF resulted in a high rate of tubal occlusion with prevention of pregnancy; refinements are needed to increase the contraceptive rate following a single treatment to near 100%.

Characterization of tubal occlusion after transcervical polidocanol foam (PF) infusion in baboons

OBJECTIVE

Our long-term goal is to develop a nonsurgical method of fallopian tubal occlusion for the purpose of permanent contraception. We have previously demonstrated that transcervical administration of 5% polidocanol foam (PF) can create tubal occlusion in macaques but that multiple treatments are required. In this study, we assessed the efficacy of various regimens of PF with and without depomedroxyprogesterone acetate (DMPA) (to control ovarian cycle phase) in the baboon.

STUDY DESIGN

Adult cycling female baboons were evaluated for tubal patency by hysterosalpingography and then received a transcervical infusion of PF with (+) or without (-) an intramuscular injection of DMPA (3.5 mg/kg). Two concentrations of PF were compared: 1% [(+) DMPA, n=5; (-) DMPA, n=3] and 5% [(+) DMPA, n=4; (-) DMPA, n=3]. Controls received (+) DMPA (n=2) or (-) DMPA, (n=3) only. The reproductive tracts were removed 1-3 months after treatment for examination.

RESULTS

No fallopian tubal occlusion was observed in negative controls (±DMPA). Histologic complete tubal occlusion was observed in 3/8 of females treated with 1% PF and in 6/7 treated with 5% PF. Histologic evaluation suggested that 1% PF is associated with prolonged chronic inflammation (more than 2-3 months), while 5% treatment eliminates the epithelial lining, at least focally, and resolves into complete occlusion within 1-2 months. This pattern of complete occlusion was seen in all 4 females that received 5% PF (+DMPA) and in 2/3 that received 5% PF (-DMPA).

CONCLUSION

In a baboon model of transcervical permanent contraception, a single treatment with 5% PF resulted in complete tubal occlusion more reliably (85%) than 1% PF (38%). Cotreatment with DMPA may improve treatment results with 5% PF but requires additional study.

IMPLICATIONS

A finding that a single transcervical treatment with 5% PF can occlude the fallopian tubes of baboon supports further study of this approach as a novel strategy for permanent contraception for women.

The fibroblast growth factor family: involvement in the regulation of folliculogenesis

Several growth factors have been identified as local regulators of follicle development and ovulation. Fibroblast growth factor (FGF) family members are potent mitogens and are involved in cell differentiation, cell migration and angiogenesis in many tissues and organs. In addition to FGF-2, which is the most-studied FGF, other important members are FGF-1, -5, -7, -8, -9 and -10. A number of studies have indicated that FGFs play important roles in regulating the initiation of primordial follicle growth, oocyte and follicle survival, granulosa and theca cell proliferation and differentiation, corpus luteum formation, steroidogenesis and angiogenesis. The purpose of this review is to highlight the importance of the FGFs on mammalian female reproduction, providing a better understanding of the roles of this family in ovarian physiology and female fertility.

Fibroblast Growth Factor (FGF)-1, FGF2, FGF7 and FGF Receptors are Uniformly Expressed in Trophoblast Giant Cells During Restricted Trophoblast Invasion in Cows

The bovine placenta is characterized by a limited invasion of trophoblast giant cells (TGC). In contrast to mononuclear trophoblast cells (MTC), TGC are non-polarized cells, which migrate and fuse with single uterine epithelial cells throughout gestation. Fibroblast growth factors (FGF) were shown to be associated with the migratory activity of cells, cell differentiation and angiogenesis, and due to its localization in trophoblast cells were proposed as important regulating factors in hemochorial placentae of rodents and humans, and the (syn)epitheliochorial placenta of pig and sheep. Since migrating bovine TGC are of epithelial origin, but exhibit similarities to mesenchymal cells we hypothesize that the restricted trophoblast invasion in cattle is characterized by a specific FGF expression pattern. Therefore, the spatiotemporal expression of specific FGF factor:receptor pairs, either acting on cells of mesenchymal origin or on epithelial cells was examined in bovine placental tissues throughout gestation and prepartum by immunohistochemistry, semiquantitative RT-PCR and in situ hybridization. FGF1 protein was found in trophoblast, caruncular epithelium (CE) and stroma (CS), stroma of chorionic villi (SCV), and in fetal and maternal blood vessels. FGF2 signals dominated in maternal vascular endothelia (VE), immature TGC, and MTC, whereas staining in other cell types was clearly weaker. FGF7 protein was detected in fetal and maternal blood vessel as well as in immature TGC and MTC predominantly at the chorionic plate. FGFR immunoreaction was localized in immature TGC, MTC, and to a clearly lesser extent in CS, CE and fetal and maternal blood vessels. Mature TGC stained negatively for all examined factors and FGFR. The corresponding mRNAs specific for FGF1, -2, -7, total FGFR, and FGFR2 isoforms IIIb and IIIc were colocalized in immature TGC, whereas hybridization was substantially lower in CE and absent in CS, SCV and mature TGC throughout gestation, but switched to CS and VE immediately prepartum. Semiquantitative RT-PCR revealed higher mRNA levels for FGF1, FGFR, and FGFR2IIIc in cotyledons compared to caruncles (p<0.05), whereas it was the opposite with FGF2 (p<0.001). FGF7 and FGFR2IIIb mRNA levels did not differ between caruncles and cotyledons. Significant changes (p<0.05) of mRNA levels related to gestational age were found for FGF1 and FGFR2IIIc, but not for FGF2, -7, total FGFR, and FGFR2IIIb. The specific localization of all examined FGF family members in TGC suggests that TGC, apart from their classical function as producers of hormonal products, play other important roles in the regulation of bovine placentomal growth, differentiation and angiogenesis.

PLAC1 expression increases during trophoblast differentiation: evidence for regulatory interactions with the fibroblast growth factor-7 (FGF-7) axis

PLAC1 is a recently described, trophoblast-specific gene that localizes to a region of the X-chromosome important in placental development. Immunohistochemical analysis demonstrated that PLAC1 polypeptide localizes to the differentiated syncytiotrophoblast throughout gestation (8-41 weeks) as well as a small population of villous cytotrophoblasts. Consistent with these observations, quantitative RT-PCR demonstrated that PLAC1 mRNA increases more than 300-fold during cytotrophoblast differentiation in culture to form syncytiotrophoblasts. Agents known to be relevant to trophoblast differentiation were then tested for the ability to influence PLAC1 expression. Fibroblast growth factor-7 (FGF-7), also known as keratinocyte growth factor (KGF), stimulated PLAC1 mRNA expression approximately two-fold in the BeWo(b30) trophoblast cell line. FGF-7 stimulation was significantly inhibited by PD-98059 and wortmannin suggesting mediation via MAP kinase and PI-3 kinase-dependent signaling pathways. Interestingly, epidermal growth factor (EGF) treatment of trophoblasts had no effect on PLAC1 expression alone, but potentiated the effect of FGF-7, suggesting the presence of a regulatory interaction of the two growth factors. FGF-7 and its receptor, FGFR-2b, exhibited spatial overlap with PLAC1 suggesting these regulatory interactions are physiologically relevant during gestation. These data demonstrate PLAC1 expression is upregulated during trophoblast differentiation, localizing primarily to the differentiated syncytiotrophoblast. Furthermore PLAC1 expression is specifically regulated by peptide growth factors relevant to trophoblast differentiation.

PLAC1, a trophoblast-specific gene, is expressed throughout pregnancy in the human placenta and modulated by keratinocyte growth factor

Plac1, a placenta-specific gene, is expressed exclusively by cells of trophoblastic lineage in the mouse, and maps to a region of the X chromosome known to be important in placental growth. These studies were undertaken to define the cellular location of the mRNA for the human orthologue, PLAC1, within the human placenta, and to examine its expression throughout gestation. By Northern analysis, PLAC1 mRNA was detected in term human placenta, migrating as a single 1.7 kb transcript, but in no other fetal or adult tissues tested. Expression was observed throughout gestation, whereas mouse Plac1 is significantly reduced after 12.5 dpc. Using an (35)S-labeled riboprobe, PLAC1 expression was trophoblast-specific at all stages of gestation (8-41 weeks); no expression was seen in cells within the stromal compartment or decidua. Using BeWo choriocarcinoma cells as a trophoblast model, keratinocyte growth factor (KGF) stimulated steady-state PLAC1 mRNA expression approximately twofold by Northern analysis and quantitative real-time PCR. Stimulation was observed only after 24 hr of exposure, suggesting that the stimulatory effect of KGF is secondary to the promotion of trophoblast growth or differentiation. No change in mRNA levels resulted from exposure to insulin-like growth factor II (IGF-II). Trophoblast-specific expression throughout gestation and responsiveness to KGF are consistent with a fundamental role for PLAC1 at the maternal-fetal interface.

Expression and action of keratinocyte growth factor (KGF) in normal ovarian surface epithelium and ovarian cancer

The current study investigates the expression and action of keratinocyte growth factor (KGF) in normal ovarian surface epithelium (OSE) and ovarian cancer tissues. Ovarian tumors are primarily derived from the OSE. KGF is a mesenchymal cell-derived growth factor that mediates stromal cell-epithelial cell interactions in a variety of different tissues. Human ovarian tumors from borderline, stage I and stage III cases were found to express KGF protein in the epithelial cell component by immunocytochemical analysis. The stromal cell component of human ovarian tumors contained little or no KGF immunostaining. Normal bovine ovaries have similarities to human ovaries and are used as a model system to investigate normal OSE functions. KGF protein was detected in the OSE from normal human and bovine ovaries by immunocytochemistry. Ovarian stromal tissue contained light but positive KGF immunostaining. RNA was collected from normal bovine OSE and ovarian stromal cells to examine KGF gene expression. KGF transcripts were detected in cultured OSE and stromal cells by Northern blot analysis. In order to examine and quantitate KGF gene expression in freshly isolated versus cultured tissues, a sensitive quantitative RT-PCR assay for KGF was utilized. KGF gene expression was found to be high in freshly isolated OSE, but very low in freshly isolated stroma. Levels of KGF gene expression after culture of OSE and stromal cells increased. Observations indicate that normal OSE express high levels of KGF in vivo and in vitro. Expression of KGF by normal epithelial cells versus stromal cells was unexpected and suggests KGF may be an important autocrine stimulator of OSE. KGF actions on bovine OSE cells were investigated. KGF was found to stimulate the growth of normal OSE cells to the same level as epidermal growth factor. Two ovarian cancer cell lines, SKOV3 and OCC1, were also stimulated to proliferate in response to KGF. Current results demonstrate the production and action of KGF on normal OSE cells and ovarian cancer cells. Observations can be interpreted to suggest that KGF may in part be involved in the growth of ovarian tumors. This appears to be one of the first reports of KGF production by an epithelial cell. The autocrine stimulation of OSE growth by the local production and action of KGF provides insight into how the OSE may develop abnormal growth characteristics involved in the onset and progression of ovarian cancer.

Trophoblast pseudo-vasculogenesis: faking it with endothelial adhesion receptors

During early development, a subset of fetal (placental) cytotrophoblasts exhibits tumor-like behavior and invades the uterus. To access a supply of maternal blood, they invade arterioles and form heterotypic interactions with, and replace, resident maternal endothelium, creating a hybrid uterine vasculature. Recently, it has become clear that invading cytotrophoblasts transform their adhesion receptor phenotype to resemble the endothelial cells they replace. Furthermore, they express vasculogenic factors and receptors. Is this a form of vasculogenesis?

Developmental and hormonal regulation of keratinocyte growth factor expression and action in the ovarian follicle

The developing ovarian follicle is one of the most rapidly proliferating normal tissues in vivo. Mesenchymal-epithelial cell interactions between theca cells and granulosa cells are essential for this follicular expansion. Ovarian hormones (i.e. estrogen and LH) may promote follicular development by regulating the local production of mesenchymal inducer proteins that mediate theca cell-granulosa cell interactions. Recently, theca cells were shown to produce keratinocyte growth factor (KGF) that can act in a paracrine manner to stimulate granulosa cell growth. In this study, the developmental and hormonal regulation of KGF was examined during follicular development in the bovine ovary. Expression of KGF in theca cells and the KGF receptor (KGFR, or splice variant of the fibroblast growth factor family receptor family, FGFR-2) in granulosa cells was examined using RT-PCR. Both KGF and KGFR were detected throughout follicular development in small (<5 mm), medium (5-10 mm), and large (>10 mm) follicles. Quantitative RT-PCR assays were used to determine steady-state levels of KGF and KGFR messenger RNAs. Developmental regulation of KGF and KGFR was analyzed in freshly isolated theca cells and granulosa cells from small, medium, and large follicles. Observations demonstrated that expression of KGF (in theca cells) and KGFR (in granulosa cells) was highest in large follicles. These results suggest that KGF actions are important for the rapid proliferation of granulosa cells in large follicles. Estrogen and LH are the primary endocrine hormones that regulate theca cell function in vivo. Therefore, hormonal regulation of KGF was analyzed by treating serum-free theca cell cultures with estrogen and human CG (hCG, an LH agonist). Results showed that both estrogen and hCG stimulated KGF gene expression in theca cells. These results suggest that estrogen and LH may promote follicular growth (i.e. granulosa cell proliferation), in part, by stimulating the local production of KGF. Effects of KGF on granulosa cell differentiated functions were examined. Treatment with KGF reduced basal levels and FSH-stimulated levels of aromatase activity in bovine and rat granulosa cells. In addition, KGF inhibited the ability of hCG to stimulate progesterone production by granulosa cells. The inhibition of granulosa cell steroid production by KGF was likely the indirect effect of promoting cellular proliferation. Therefore, KGF directly stimulates granulosa cell proliferation and indirectly inhibits granulosa cell differentiated functions. Combined results suggest that theca cell production of KGF may be important for ovarian folliculogenesis. This is the first report of the regulation of KGF expression in the ovary. The developmental and hormonal regulation of KGF and KGFR during folliculogenesis provides evidence that KGF may be important for hormone-induced granulosa cell proliferation. As a result, KGF may be essential for establishing the microenvironment required for oocyte maturation in the ovary.

Keratinocyte growth factor expression in the mesenchymal cells of human amnion

Amnion epithelial and mesenchymal cells were separated by differential protease treatment, and the separated cells were maintained in monolayer culture. Keratinocyte growth factor (KGF) messenger RNA (mRNA) was readily detected by Northern analysis of amnion mesenchymal cell total RNA (10 micrograms) but not in amnion epithelial cells. Treatment of the amnion mesenchymal cells in serum-free medium with tetradecanoyl phorbol acetate (1 nM) caused an increase in the level of KGF mRNA. Forskolin treatment also caused an increase in KGF mRNA but not to the levels attained with tetradecanoyl phorbol acetate treatment. Dexamethasone (1 nM) treatment of these cells effected a reduction in the level of KGF mRNA. Prolonged maintenance of mesenchymal cells in serum-free medium also was associated with an increase in the level of KGF mRNA. Treatment with a variety of other agents, viz., interleukin (IL)-1, IL-6 plus or minus IL-6 soluble receptor, IL-11, oncostatin M, epidermal growth factor (EGF), and transforming growth factor-beta and not modify the level of KGF mRNA. Treatment of amnion epithelial cells with KGF caused an increase in the rate of [3H]thymidine incorporation, but the rate of cell replication induced by KGF was less than that induced by treatment with EGF. Transforming growth factor-beta treatment inhibited basal and EGF- and KGF-stimulated amnion epithelial cell replication. The findings of this study are indicative the KGF is expressed in human amnion mesenchymal cells, and that KGF may act on the epithelial cells of this tissue.