Nina Pedersen

Expression of a naturally occurring constitutively active variant of the epidermal growth factor receptor in mouse fibroblasts increases motility

Tumor cell motility is one of the rate‐limiting steps of invasion, which defines progression toward a more malignant phenotype. Elevated expression of epidermal growth factor receptor (EGFR) in many cancers is associated with progression of superficial to invasive forms of the disease. The naturally occuring type III mutant epidermal growth factor receptor (EGFRvIII) is a tumor‐specific, ligand‐independent, constitutively active variant of the epidermal growth factor receptor. EGFRvIII is expressed frequently by a number of human solid tumours including those of the lung, breast, prostate, brain and ovary. Our study was designed to investigate the effect of EGFRvIII expression on cell motility and compare it to that of ligand‐activated EGFR using transfected fibroblasts. We show here using time‐lapse video recording that expression of EGFRvIII greatly enhances the motility of fibroblasts independently of ligand stimulation. In addition, expression of EGFRvIII caused a marked increase in the number of cellular protrusions (lamellipodia) and a reduction in the number of stress fibers and focal adhesions. The EGFR tyrosine kinase inhibitor, AG1478, and the MEK inhibitor, U0126, blocked these cellular effects of EGFRvIII. Two cell lines expressing different levels of EGFR were used for comparison. The low‐expressing cell line responded to EGF treatment by increasing motility in a manner very similar to the motility induced by EGFRvIII. In contrast, the high‐expressing cell line responded to EGF by detachment from the extracellular matrix and decreased motility. Cellular detachment was correlated to a high phosphorylation of PLC‐γ, whereas increased motility was correlated to a high level of ERK phosphorylation. Overall these results indicate that tumor‐associated EGFR mutations might be critical for tumor cell motility, invasion and thus progression of disease.

Analysis of the epidermal growth factor receptor specific transcriptome: Effect of receptor expression level and an activating mutation

Overexpression or expression of activating mutations of the epidermal growth factor receptor (EGFR) is common in cancer and correlates with neoplastic progression. The present study employed Affymetrix® oligonucleotide arrays to profile genes induced by ligand‐activated EGFR with the receptor either moderately expressed or overexpressed at an in‐itself transforming level. These changes were compared to those induced by the naturally occurring constitutively active variant EGFRvIII. This study provides novel insight on the activities and mechanisms of EGFRvIII and EGFR mediated transformation, as genes encoding proteins with functions in promoting cell proliferation, invasion, antiapoptosis, and angiogenesis featured prominently in the EGFRvIII‐ and EGFR‐expressing cells. Surprisingly, it was found that ligand‐activated EGFR induced the expression of a large group of genes known to be inducible by interferons. Expression of this module was absent in the EGFRvIII‐expressing cell line and the parental cell line. Treatment with the specific EGFR inhibitor AG1478 indicated that the regulations were primary, receptor‐mediated events. Furthermore, activation of this module correlated with activation of STAT1 and STAT3. The results thus demonstrate that ligand‐activated EGFR at different expression levels results in different kinetics of signaling and induction of gene expression. In addition, the constitutively active variant EGFRvIII seems to activate only a subset of signal pathways and induce a subset of genes as compared to the ligand‐activated EGFR.

Early Fetal Size and Growth as Predictors of Adverse Outcome

OBJECTIVE: To evaluate the association between fetal size and growth between the first and second trimesters and subsequent adverse pregnancy outcome. METHODS: A cohort was created of 7,642 singleton pregnancies cared for in three obstetric units associated with Copenhagen University. Data were obtained from ultrasound measurements at 11–14 weeks (crown-rump length, biparietal diameter) and 17–21 weeks (biparietal diameter). Fetal size was assessed by gestation-specific z scores, and fetal growth between the first and second trimester was calculated individually using conditional centiles. The main outcome measures were preterm delivery, smallness for gestational age, and perinatal death. RESULTS: Slow growth of the biparietal diameter less than the 10th and less than the 2.5th conditional centiles between first and second trimesters occurred in 10.4% and 3.6% of the population, respectively. Biparietal diameter growth less than the 10th centile was associated with perinatal death before 34 weeks (risk 0.5% compared with 0.04%, odds ratio [OR] 16.0, confidence interval [CI] 2.9–88.7). Biparietal diameter growth less than the 2.5th centile was the best predictor of perinatal death at any gestation, with a positive likelihood ratio of 4.7 and an OR of 7.3 (CI 2.4–22.2). In contrast, the biparietal diameter, dated by crown-rump length, did not have an increased risk of perinatal death; however, there was a mildly increased risk of small for gestational age birth weight (less than the 10th customized centile) if the biparietal diameter was below the 10th centile in the first trimester (risk 17% compared with 12%, OR 1.5, CI 1.2–1.8) or in the second trimester (risk 15.8% compared with 12.4%, OR 1.3, CI 1.1–1.5). CONCLUSION: Slow growth of the fetal biparietal diameter between the first and second trimesters of pregnancy is a strong predictor of perinatal death before 34 weeks. LEVEL OF EVIDENCE: II

Fetal growth between the first and second trimesters and the risk of adverse pregnancy outcome

To relate growth rate of the biparietal diameter (BPD) between the first and second trimesters to the risk of perinatal death, intrauterine growth restriction (IUGR), macrosomia, preterm/post‐term delivery and pre‐eclampsia.

Identification of novel peptide ligands for the cancer-specific receptor mutation EFGRvIII using a mixture-based synthetic combinatorial library.

We report here, the design and synthesis of a positional scanning synthetic combinatorial library for the identification of novel peptide ligands targeted against the cancer‐specific epidermal growth factor tyrosine kinase receptor mutation variant III (EGFRvIII). This receptor is expressed in several kinds of cancer, in particular, ovarian, glioblastomas, and breast cancer, but not in normal tissue. The library consisted of six individual positional sublibraries in the format, H‐O1–6XXXXX‐NH2, O being one of the 19 proteinogenic amino acids (cysteine omitted) and X an equimolar mixture of these. The library consisted of 114 mixtures in total. Using a biotin‐streptavidin assay, the binding of each sublibrary to NR6M, NR6W‐A, and NR6 cells was tested. These cells express EGFRvIII, EGFR, and neither of the receptors, respectively. The result from each sublibrary was examined to identify the most active amino acid residue at each position. On the basis of this knowledge, eight peptides were synthesized and tested for binding to EGFRvIII. We identified one peptide, H‐FALGEA‐NH2, that showed more selective binding to the mutated receptor than the EGFRvIII specific peptide PEPHC1. This study demonstrates the value of using mixture‐based combinatorial positional scanning libraries for the identification of novel peptide ligands targeted against the cancer‐specific EGFRvIII. Our best candidate H‐FALGEA‐NH2 will be radioactively labeled and evaluated as an imaging agent for positron emission tomography investigation for diagnosis, staging, and monitoring of therapy of various types of cancer.

Mono-ovulation in women with polycystic ovary syndrome: a clinical review on ovulation induction

Polycystic ovary syndrome (PCOS) affects 5-10% of women of reproductive age and is the most common cause of anovulatory infertility. The treatment approaches to ovulation induction vary in efficacy, treatment duration and patient friendliness. The aim was to determine the most efficient, evidence-based method to achieve mono-ovulation in women diagnosed with PCOS. Publications in English providing information on treatment, efficacy and complication rates were included until September 2015. Systematic reviews, meta-analyses and randomized controlled trials were favoured over cohort and retrospective studies. Clomiphene citrate is recommended as primary treatment for PCOS-related infertility. It induces ovulation in three out of four patients, the risk of multiple pregnancies is modest and the treatment is simple and inexpensive. Gonadotrophins are highly efficient in a low-dose step-up regimen. Ovulation rates are improved by lifestyle interventions in overweight women. Metformin may improve the menstrual cycle within 1-3 months, but does not improve the live birth rate. Letrozole is effective for ovulation induction, but is an off-label drug in many countries. Ovulation induction in women with PCOS should be individualized with regard to weight, treatment efficacy and patient preferences with the aim of achieving mono-ovulation and subsequently the birth of a singleton baby.

Maternal serum placental growth hormone, but not human placental lactogen or insulin growth factor‐1, is positively associated with fetal growth in the first half of pregnancy

To investigate if maternal levels of human placental lactogen (hPL), placental growth hormone (PGH) and insulin‐like growth factor‐1 (IGF‐1) are associated with growth rate of the biparietal diameter (BPD) in the first half of pregnancy.

Hormone therapy modulates ETA mRNA expression in the aorta of ovariectomised New Zealand White rabbits

Objective. To study the effect of 17β-estradiol (E2) or conjugated equine estrogens (CEE) alone and in combination with norethisterone acetate (NETA) or medroxyprogesterone acetate (MPA) on the endothelin-1 (ET-1) system. Methods. New Zealand White rabbits were treated with E2, CEE, E2 + NETA, CEE + MPA or placebo. The thoracic aorta and the epicardial coronary artery were used for mRNA expression and myograph analyses, respectively. Results. E2 and CEE alone significantly reduced ET-1 receptor subtype A (ETA) mRNA expression compared with placebo treatment. The E2-induced reduction in ETA mRNA expression persisted with the co-administration of NETA, but the CEE induced reduction in ETA mRNA expression was not maintained with the co-administration of MPA. Treatment with CEE alone significantly increased endotelin-1 converting enzyme (ECE) mRNA expression and CEE combined with MPA reduced prepro-endothelin-1 (ppET-1) mRNA expression when compared with placebo. ET-1 receptor subtype B mRNA expression and ET-1 induced vasocontraction was unaffected by treatment. Conclusions. E2 and CEE treatment exert potentially beneficial vascular effects through regulation of the ETA receptor. The effect was maintained with the co-administration of NETA, but not MPA. The differential effects of specific hormone components may explain the variable effects of hormone therapy on the arterial wall.

First trimester growth restriction and uterine artery blood flow in the second trimester as predictors of adverse pregnancy outcome

OBJECTIVES To investigate if fetuses with first trimester growth restriction have poorer perfusion of the placenta compared to a control group, and to investigate whether first trimester growth restriction in combination with poor flow in the uterine arteries in the second trimester can be used to predict poor outcome. STUDY DESIGN Women with singleton pregnancies, where the gestational age estimated by crown-rump length (CRL) at the first trimester scan was 7 days or more smaller than the gestational age estimated by last menstrual period, and a control group of women, where the gestational age was either equal to or 1 day larger than the gestational age estimated by last menstrual period, were invited to join the study. The study entailed the routine scans; Down syndrome screening in gestational week 11-14 and an anomaly scan in gestational week 18-21. In addition to the routine scans the participants were offered a growth scan in gestational week 23-24. At the anomaly scan and growth scan, umbilical and uterine artery Doppler flows were measured. RESULTS 182 cases and 230 controls were included in the study. The case and control groups showed no significant differences in placental blood flow characteristics at 18-21 weeks or 23-24 weeks. In our logistic regression models the only outcome that showed a significant association to the case group was birth weight below 2500 g. Having a CRL 7 days or more smaller than expected increased the risk of having a child with a birth weight below 2500 g with an odds ratio of 3.29. CONCLUSIONS We were unable to demonstrate a link between first trimester growth restriction and poor placental perfusion. The case group had increased risk of birth weight below 2500 g, but only with an odds ratio of 3. Therefore we do not recommend implementation of uterine or umbilical artery flow measurements specifically for fetuses with first trimester growth restriction.

Plasma progesterone, estradiol, and unconjugated estriol concentrations in twin pregnancies: Relation with cervical length and preterm delivery

The aim of this study was to examine the association between plasma hormone concentrations, cervical length, and preterm delivery in twin pregnancies, including the effect of progesterone treatment.