Research group leader:
Hormonal effects in the female reproductive tract
A second type of estrogen receptor, named β (ERβ), was discovered in 1996. In order to elucidate if the regulation of the "classic" ERα and ERβ is different we have studied the expression of the two subtypes in the female reproductive tract during different hormonal conditions.
In addition, we study the cross-talk between ERs and the other steroid hormone receptors. In recent years there have been evidence also of membrane bound steroid hormone receptors e.g. GPER (G-protein bound estrogen receptor 1), PGRMC (progesterone receptor membrane component) 1 and PGRMC2, which could explain some of the very fast effects seen after hormone treatment which cannot be mediated via the classical nuclear receptors since nuclear/genomic signaling requires longer time.
1. Estrogen effects on leukocytes.
Leukocytes in human cervix are positively immunostained for ERβ. Several types of leukocytes express ERβ and the metalloproteinase-2 (MMP-2) and MMP-9. Estrogens might therefore have direct effects on leukocytes via activation of ERβ, which could result in influx of specific leukocytes and increased synthesis of factors (e.g cytokines and metalloproteinases) important for remodeling of the cervix. Periferal human leukocytes express both ERα and ERβ proteins. In monocytes there are mRNAs for both ERα and ERβ, while polymorphonuclear leukocytes only express modified mRNAs. By help of a microarray technique it is possible to study the genes that are regulated by estrogens in the leukocytes. We treat leukocytes in vitro (differentiated HL-60 cells) with specific ER agonists and investigate the genes with affected gene expression. We found that different genes were regulated depending on which estrogen receptor that was activated. The results are verified with q-RT-PCR and Western Blot.
2. Expression of sex steroid receptors and stromal factors in malignant and benign breast tissues – relation to prognostic outcome (PhD project: Mia Fahlén; collaboration with Ass prof Eva von Schoultz and Professor Bo von Schoultz)
Are there significant differences in sex steroid receptor expression between malignant and benign breast tissue from the same premenopausal women? Are such differences associated with prognostic outcome as estimated by the Nottingham Prognostic Index? Malignant and benign breast tissues were collected during surgery at the Breast Cancer Unit at St Göran´s Hospital. Information on reproductive history and previous hormonal therapies were obtained from a standardized questionnaire. Paired tissue samples (tumor and adjacent “normal” tissue) are analyzed for the expression of steroid hormone receptors and stromal factors on both mRNA and protein level. ER and progesterone receptor (PR) isoforms and androgen receptor (AR) are quantified by digitized image analysis after immunohistochemical staining. Hormone receptor expression at the time of surgery is studied by q-RT-PCR for mRNA. Results will be correlated to circulating levels of hormones and prognostic outcome as calculated by the Nottingham Prognostic Index.
The breast is a target organ for estrogen and other sex steroid hormones. There is still a lack in basic understanding on how hormones exert their influence in breast tissue. Most of our knowledge in this field comes from cell culture experiments and animal data. Comparative human data are clearly needed. Our understanding of the interplay between sex steroid receptors in agonist/antagonist actions and of paracrine signaling between stroma and epithelium is limited.
3. To study endometrial factors, i.e. steroid hormone receptors, in relation to endocrine status in women with PCOS compared to controls (collaboration with MD, PhD Mariana Hulchiy and Professor Angelica Lindén Hirschberg).
PCOS, polycystic ovary syndrome, is one of the most common causes of female infertility, affecting 5-10% women of reproductive age, whereas polycystic ovaries are found in up to 20% of women in reproductive age. A major concern for the women affected by PCOS is the decreased fertility. Not only is the cause the absent and/or irregular ovulations, but also endometrial disturbances have been suggested. In the present project we will focus on determining factors in the endometrium that could be related to the reduced fecundity, as well as the increased risk of miscarriage in these patients. Women with PCOS are recruited from the outpatient clinic at the Karolinska University Hospital. Endometrial tissues are obtained from PCOS women and controls on cycle day 6-8 days after ovulation or cycle day 21-23 of the menstrual cycle in anovulatory women. In amenorrheic patients, menstruation will be induced by progestational medication. The tissue will be analyzed for mRNA and protein levels of sex steroid hormone receptors, GPER, PGRMC1 and PGRMC2, as well as receptors in thyroid hormone signaling. These biomarkers of endometrial receptivity will be analyzed by immunohistochemistry and real time PCR. Ovarian function will be evaluated by vaginal ultrasonography and serum hormone measurements.
In a second part endometrial factors and ovarian function will be studied in PCOS women before and after life-style intervention aiming at weight reduction in overweight patients (BMI >27). Recruitment and general inclusion criteria are the same as in the first part of the study. An individually adapted program of dietary restriction and physical exercise will be supervised by a dietician and a physical therapist. Endometrial biopsies will be collected on cycle day 6-8 before and after the intervention.
4. Identification of factors indicating residual ovarian pool and their impact to determine fertility preservation methods among childhood cancer patients (PhD project Valentina Pampanini; collaboration with Ass Prof Kirsi Jahnukainen).
Knowledge of the regulation of normal ovarian development is sparse but increasingly important for supporting the growing number of women who postpone having children, thereby often experiencing difficulties in becoming pregnant. A tool to determine ovarian status and degree of follicular activity could help to guide these women.
An increasing number of women are survivors of childhood cancer. The ovarian reserve of these girls may be significantly reduced and they render a high risk for premature menopause at young adult age. Also here a tool to predict the degree of activity in ovarian function would support these women and their doctors in deciding which reproductive assistance would be most beneficial.
Thus, a thorough study on proliferative and apoptotic factors during ovarian development would give the necessary knowledge of the normal situation in puberty and adolescence. Knowledge of the normal situation is a necessity for being able to understand when something goes wrong.
Mia Fahlén, MD, PhD student
Maryana Hulchiy, MD, PhD
Valentina Pampanini, MD, PhD student
Britt Masironi, Technician