Department for BioMedical Research (DBMR)

Endometriosis and Gynaecological Oncology

Endometriosis and inflammation (Group leader: Nick A. Bersinger, PhD)

Endometriosis is an extremely prevalent condition that is accompanied by chronic pain, reduced fecundity and an increased risk of ovarian cancer later in life (see below) – all of which can be related to inflammation. The most widely accepted theory of endometriotic lesion development is retrograde menstruation, a process by which viable endometrial cells are refluxed backwards into the peritoneal cavity. These cells attach to the underlying tissue and via a hormonal and inflammatory stimulation continue to grow. As retrograde menstruation has been shown to occur in almost 90% of women additional factors must be involved that support the attachment of the endometrial tissue in those patients who suffer from endometriosis.

We are studying the presence of pro- and anti-inflammatory cytokines, angiogenic, neurogenic, and growth factors in the peritoneum at both the gene expression and functional protein level. Transcriptional investigations (RT and Q-PCR on the above marker genes) are performed with RNA obtained from fresh endometrial tissue. At the protein level immunohistochemistry and Western blot analyses are performed on both eutopic (intra-uterine) and ectopic (extra-uterine endometriotic lesion) tissue as well as on peritoneal fluid (PF) collected from the peritoneal cavity (cul-de-sac = pouch of Douglas) during the laparoscopic intervention. Various inflammatory cytokines and growth factors are determined in the PF by microplate immunoassays using either manual ELISA protocols (commercial or developed in our laboratory) or multiplexed double fluorescence Luminex (x-map) technology based assays on the Bioplex® platform.

Results are set in relation to the clinical situation such as the presence, frequency and intensity of pain (dysmenorrhoea, lower abdominal pain, dysuria, dyschezia and dyspareunia), fertility, and the use of medicines (essentially hormonal preparations). Cultures of endometrial cell lines and of primary endometrial cells (epithelial and stromal) are used as models for studying cytokine, angiogenic and neuro-stimulatory marker production in vitro after stimulation by hormones and growth factors.
To date it seems unlikely that a single, "miracle" peritoneal fluid, and even less so serum marker would be identified for the detection of or screening for the presence of endometriosis in the near future. It is extremely difficult to build homogeneous patient cohorts for case and control groups, and it is therefore no surprise that the literature is inconsistent – even for single specific markers. Time to diagnosis of endometriosis and initiation of hormonal or surgical treatment is still far too long. We have collected PF and other materials since 2011 and hope, with this large biobank, to soon be able to define marker algorithms which would accelerate this identification process.
Nick A. Bersinger

Gynaecological Oncology (Group leader: Thomas Andrieu, PhD)

Endometriosis is as such a benign condition but, unfortunately, it is associated with specific ovarian cancer subtypes: clear cell and endometrioid carcinoma subtypes (also named endometriosis-associated ovarian cancers, EAOC). Direct transformation of endometriotic epithelial cells to a malignant endometrioid, or clear cell ovarian cancer has been documented, although what stimulates this transformation is unclear.

Molecular studies have identified several somatic mutations, such as the inactivating mutations of the tumour suppressor gene ARID1A, in endometriotic lesions, atypical endometriosis and EAOC. Those mutations rarely occur in other ovarian cancer subtypes and, most importantly, they are not present in distal endometriotic lesions. Therefore they are believed to arise early in the malignant process. Although an important early step in epithelial tumorigenesis, an ARID1A mutation that would happen in isolation is insufficient to create a neoplastic cell suggesting that other stimuli participate to the epithelial malignant transformation.

We are therefore interested to determine how the inflammatory microenvironment created by endometriosis can stimulate the progression from a benign to malignant lesion. The strength of our project is the large number of samples obtained from the Department of Obstetrics and Gynaecology at the University of Berne and constantly accumulated in our biobank initiated for this purpose. Our approach is to closely study the interactions between stromal and epithelial cells in a three-dimensional co-culture model using reprogrammed epithelial cells and the artificial knock down of ARID1A gene by CRISPR/Cas9. Ultimately the co-culture model is intended to be integrated within a “lab-on-a-chip” structure using the microfluidic technology which is indeed expected to represent ideally the physiological conditions.

Understanding the mechanisms of malignant progression may provide some clues towards establishing an early diagnosis. This is of importance since nowadays women with a diagnosis of ovarian endometriosis have no predictive risk assessing test available for endometrial ovarian cancer occurrence even through this lethal disease could be avoided by fallopian tube ligation or adnexectomy.
Thomas Andrieu