Saliva samples as a source of DNA for high throughput genotyping: an acceptable and sufficient means in improvement of risk estimation throughout mammographic diagnostics.

BACKGROUND: Breast cancer screening programs seem to be an insufficient tool for women at high genetic risk for breast cancer. These women are not adequately monitored yet. Genetic testing may improve clearly the quality of breast cancer prevention programs. At present, blood samples are favored for obtaining high-quality DNA; however, DNA can also be obtained by collecting saliva. The aim of this study was, on the one hand, to determine whether saliva sampling is a practicable means to obtain sufficient quantity and quality of DNA and, on the other hand, whether it is accepted by patients throughout mammographic diagnostics. METHODS: 67 consecutive women with diagnostic need for mammography with or without a family history for breast cancer were asked for their basic willingness to undergo a genetic testing by saliva sample in addition to standard diagnostics. Saliva samples were analyzed in terms of DNA quantity and quality. RESULTS: 64 (95.6%) women agreed to provide a saliva sample; 3 of them denied participation. And even 63 out of 64 (98.4%) were interested in their specific results. 45 out of 64 samples contained a DNA concentration above 50 ng/µl, 12 samples were between 25 and 50 ng/µl and only 7 of them were under 25 ng/µl with the standard extraction procedure. CONCLUSION: A high number of patients seem to accept salvia samples as a risk assessment tool in breast diagnostics and are interested in their specific risk situation. At the same time, it could be demonstrated that it is an effective way to provide high-quality DNA for breast cancer gene analysis. However, it remains to be shown whether it would be possible to integrate it with the same acceptance in a nationwide breast cancer screening program.

Detyrosinated tubulin is decreased in fetal vessels of preeclampsia placentas.

INTRODUCTION: Preeclampsia is a hypertensive, gestational disease, which is still the leading cause of pregnancy related morbidity and mortality. The impairment of placental angiogenesis and vascularization is discussed to be of etiopathologic relevance. Deytrosination and tyrosination of α-tubulin is important for the stability and dynamics of microtubules. An increase of α-tubulin detyrosination leads to microtubule stabilization, which is an essential prerequisite for physiologic vascular tube morphogenesis during angiogenesis. So far, little is known about the specific localization of detyrosinated (detyr) and tyrosinated (tyr) tubulin in the placenta and its relevance for preeclampsia. METHODS: Placental expression of detyr- and tyr-tubulin was analyzed by immunohistochemistry, immunofluorescence and western blot. For western blot quantification we used biopsies from healthy placentas (n = 21) and placentas from pregnancies complicated with small for gestational age (n = 5), preeclampsia (n = 5) or both (n = 5). RESULTS: Specific placental localization of detyr-tubulin was detected in the fetal endothelial cells of the placenta. Villous and extravillous trophoblasts as well as villous stroma cells were tyr-tubulin positive. Detyr-tubulin protein expression was significantly decreased in placentas complicated by preeclampsia. CONCLUSIONS: In summary, we report an accumulation of detyr-tubulin in villous vessels of the placenta and a significantly reduced level of detyr-tubulin in placental biopsies of preeclampsia cases. The reduction of placental detyr-tubulin in preeclampsia could suggest a deficit in villous vascular plasticity and might be associated with the impaired arborization of the disease.

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).

The placental mTOR-pathway: correlation with early growth trajectories following intrauterine growth restriction?

Idiopathic intrauterine growth restriction (IUGR) is a result of impaired placental nutrient supply. Newborns with IUGR exhibiting postnatal catch-up growth are of higher risk for cardiovascular and metabolic co-morbidities in adult life. Mammalian target of rapamycin (mTOR) was recently shown to function as a placental nutrient sensor. Thus, we determined possible correlations of members of the placental mTOR signaling cascade with auxologic parameters of postnatal growth. The protein expression and activity of mTOR-pathway signaling components, Akt, AMP-activated protein kinase α, mTOR, p70S6kinase1 and insulin receptor substrate-1 were analysed via western blotting in IUGR v. matched appropriate-for-gestational age (AGA) placentas. Moreover, mTOR was immunohistochemically stained in placental sections. Data from western blot analyses were correlated with retrospective auxological follow-up data at 1 year of age. We found significant catch-up growth in the 1st year of life in the IUGR group. MTOR and its activated form are immunohistochemically detected in multiple placental compartments. We identified correlations of placental mTOR-pathway signaling components to auxological data at birth and at 1 year of life in IUGR. Analysis of the protein expression and phosphorylation level of mTOR-pathway components in IUGR and AGA placentas postpartum, however, did not reveal pathognomonic changes. Our findings suggest that the level of activated mTOR correlates with early catch-up growth following IUGR. However, the complexity of signals converging at the mTOR nexus and its cellular distribution pattern seem to limit its potential as biomarker in this setting.

The tumor suppressor gastrokine-1 is expressed in placenta and contributes to the regulation of trophoblast migration.

INTRODUCTION: Gastrokine-1 (GKN1) is a secreted auto-/paracrine protein, described to be expressed in the gastric mucosa. In gastric cancers GKN1 expression is commonly down-regulated. While current research focusses on the exploration of tumor-suppressive properties of GKN1 with regard to its potential clinical use in the treatment of gastroenterologic tumor disease, nothing is known about GKN1 expression and function in other organ systems. We investigated GKN1 expression in placental tissue and cells. MATERIALS AND METHODS: GKN1 was localized using immunohistochemistry in first and third trimester placental tissue, hydatidiform moles and various gestational trophoblastic neoplasias. We determined the expression of GKN1 in immunomagnetic bead-separated term placental cells and in choriocarcinoma cell lines. The role of GKN1 for JEG-3 migration was studied using live cell imaging. E-cadherin, MMP-2 and -9, TIMP-1 and -2, as well as urokinase (uPA) expression levels were determined. RESULTS: GKN1 is expressed in healthy third trimester placentas. Its expression is specifically limited to the extravillous trophoblast (EVT). GKN1 expression is significantly reduced in choriocarcinoma cell lines and gestational trophoblastic neoplasias. GKN1 attenuates the migration of JEG-3 choriocarcinoma cells in vitro, possibly via AKT-mediated induction of E-cadherin. GKN1 treatment reduced MMP-9 expression in JEG-3. DISCUSSION: Besides its role in gastric physiology our results clearly indicate regulatory functions of GKN1 in the EVT at the feto-maternal interface during pregnancy. Based on our findings in the JEG-3 choriocarcinoma cell line, an auto-/paracrine role of GKN1 for EVT motility and villous anchorage at the basal plate is conceivable. Thus, the tumor suppressor GKN1 is expressed in placental EVT and might contribute to the regulation of EVT migration/invasion.