Hypermethylation and loss of retinoic acid receptor responder 1 expression in human choriocarcinoma

Background

Human placental development resembles tumorigenesis, due to the invasive and fusogenic potential of trophoblasts. However, these features are tightly controlled in trophoblasts. Disturbance of this spatial and temporal regulation is thought to contribute to the rare formation of choriocarcinomas. Promoter hypermethylation and loss of the tumor suppressor Retinoic acid receptor responder 1 (RARRES1) were shown to contribute to cancer progression. Our study investigated the epigenetic and transcriptional regulation of RARRES1 in healthy human placenta in comparison to choriocarcinoma cell lines and cases.

Methods

Three choriocarcinoma cell lines (Jeg-3, JAR and BeWo) were treated with three different retinoic acid derivates (Am580, Tazarotene and all-trans retinoic acid) and 5-aza-2′-deoxycytidine. We analyzed RARRES1 promoter methylation by pyrosequencing and performed realtime-PCR quantification to determine RARRES1 expression in placental tissue and trophoblastic cell lines. Additionally, RARRES1 was stained in healthy placentas and in biopsies of choriocarcinoma cases (n = 10) as well as the first trimester trophoblast cell line Swan71 by immunofluorescence and immunohistochemistry.

Results

In the choriocarcinoma cell lines, RARRES1 expression could not be induced by sole retinoic acid treatment. Stimulation with 5-aza-2′-deoxycytidine significantly induced RARRES1 expression, which then could be further increased with Am580, Tazarotene and all-trans retinoic acid. In comparison to healthy placenta, choriocarcinoma cell lines showed a hypermethylation of the RARRES1 promoter, which correlated with a reduced RARRES1 expression. In concordance, RARRES1 protein expression was lost in choriocarcinoma tissue. Additionally, in the trophoblastic cell line Swan71, we found a significant induction of RARRES1 expression with increased cell density, during mitosis and in syncytial knots.

Conclusions

Our findings showed that RARRES1 expression is absent in choriocarcinoma due to promoter methylation. Based on our analysis, we hypothesize that RARRES1 might exert tumor suppressive functions in multiple cellular processes (e.g. cell cycle regulation, adhesion, invasion and apoptosis).

Electronic supplementary material

The online version of this article (10.1186/s13046-017-0634-x) contains supplementary material, which is available to authorized users.

Diagnosis, Therapy and Follow-up Care of Vulvar Cancer and its Precursors. Guideline of the DGGG and DKG (S2k-Level, AWMF Registry Number 015/059, November 2015

Purpose: This is an official guideline, published and coordinated by the Arbeitsgemeinschaft Gynäkologische Onkologie (AGO, Study Group for Gynecologic Oncology) of the Deutsche Krebsgesellschaft (DKG, German Cancer Society) and the Deutsche Gesellschaft für Gynäkologie und Geburtshilfe (DGGG, German Society for Gynecology and Obstetrics). The number of cases with vulvar cancer is on the rise, but because of the former rarity of this condition and the resulting lack of literature with a high level of evidence, in many areas knowledge of the optimal clinical management still lags behind what would be required. This updated guideline aims to disseminate the most recent recommendations, which are much clearer and more individualized, and is intended to create a basis for the assessment and improvement of quality care in hospitals. Methods: This S2k guideline was drafted by members of the AGO Committee on Vulvar and Vaginal Tumors; it was developed and formally completed in accordance with the structured consensus process of the Association of Scientific Medical Societies in Germany (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften, AWMF). Recommendations: 1. The incidence of disease must be taken into consideration. 2. The diagnostic pathway, which is determined by the initial findings, must be followed. 3. The clinical and therapeutic management of vulvar cancer must be done on an individual basis and depends on the stage of disease. 4. The indications for sentinel lymph node biopsy must be evaluated very carefully. 5. Follow-up and treatment for recurrence must be adapted to the individual case.

Indications and Route of Hysterectomy for Benign Diseases. Guideline of the DGGG, OEGGG and SGGG (S3 Level, AWMF Registry No. 015/070, April 2015)

Background: Official guideline "indications and methods of hysterectomy" to assign indications for the different methods published and coordinated by the German Society of Gynecology and Obstetrics (DGGG), the Austrian Society of Gynecology and Obstetrics (OEGGG) and the Swiss Society of Gynecology and Obstetrics (SGGG). Besides vaginal and abdominal hysterectomy, three additional techniques have been implemented due to the introduction of laparoscopy. Organ-sparing alternatives were also integrated. Methods: The guideline group consisted of 26 experts from Germany, Austria and Switzerland. Recommendations were developed using a structured consensus process and independent moderation. A systematic literature search and quality appraisal of benefits and harms of the therapeutic alternatives for symptomatic fibroids, dysfunctional bleeding and adenomyosis was done through MEDLINE up to 6/2014 focusing on systematic reviews and meta-analysis. Results: All types of hysterectomy led in studies to high rates of patient satisfaction. If possible, vaginal instead of abdominal hysterectomy should preferably be done. If a vaginal hysterectomy is not feasible, the possibility of a laparoscopic hysterectomy should be considered. An abdominal hysterectomy should only be done with a special indication. Organ-sparing interventions also led to high patient satisfaction rates, but contain the risk of symptom recurrence. Conclusion: As an aim, patients should be enabled to choose that therapeutic intervention for their benign disease of the uterus that convenes best to them and their personal life situation.

[Myofibroblasts and afferent signalling in the urinary bladder. A concept]

Afferent signal transduction in the urinary bladder is still not clearly understood. An increasing body of evidence supports the view of complex interactions between urothelium, suburothelial myofibroblasts, and sensory nerves. Bladder tissue from tumour patients was used in this study. Methods included confocal immunofluorescence, polymerase chain reaction, calcium imaging, and fluorescence recovery after photobleaching (FRAP).Myofibroblasts express muscarinic and purinergic receptors. They show constitutive spontaneous activity in calcium imaging, which completely depends on extracellular calcium. Stimulation with carbachol and ATP-evoked intracellular calcium transients also depend on extracellular calcium. The intensive coupling between the cells is significantly diminished by incubation with TGF-beta 1. Myofibroblasts form an important cellular element within the afferent signalling of the urinary bladder. They possess all features required to take part in the complex interactions with urothelial cells and sensory nerves. Modulation of their function by cytokines may provide a pathomechanism for bladder dysfunction.