Reproducibility of mRNA-Based Testing of ESR1, PGR, ERBB2, and MKI67 Expression in Invasive Breast Cancer-A Europe-Wide External Quality Assessment.

Estrogen receptor (ER), progesterone receptor (PgR), Ki-67, and HER2 immunohistochemistry (IHC) together with HER2 in situ hybridization (ISH) are utilized to classify invasive breast cancer (IBC) into predictive molecular subtypes. As IHC evaluation may be hampered by analytical errors, gene expression assays could offer a reliable alternative. In this first Europe-wide external quality assessment (EQA) study, we investigated performance of mRNA-based Xpert® Breast Cancer STRAT4 (CE-IVD) in five European laboratories. The cohort comprised ten pre-therapy IBC core biopsies diagnosed in the coordinating center (CC). STRAT4 binary (positive or negative) mRNA results of each marker (ESR1, PGR, ERBB2, MKI67) were compared with the gold standard IHC/ISH performed by the CC. Sensitivity, specificity, and accuracy of ESR1 and ERBB2 mRNA were 100% for all samples. In contrast, PGR expression was falsely negative for one case by two sites and MKI67 falsely negative for two cases (respectively by four and one sites). These cases had STRAT4 expression values close to assay cut-offs and immunohistochemically presented heterogeneous low positive PgR and heterogeneous Ki-67. Our EQA shows that STRAT4 mRNA assay may be a reproducible method to evaluate ER, PgR, HER2, and Ki-67 status. However, cases with expression values close to assay cut-offs should be carefully reviewed.

Influence of calcitriol on prostaglandin- and vitamin D-metabolising enzymes in benign and malignant breast cell lines.

BACKGROUND: Cyclooxygenase-2 (COX-2) is a potential molecular prognostic factor for breast cancer, and calcitriol [1,25(OH)(2)D(3)], the biologically active form of vitamin D, is a promising target in breast cancer therapy. MATERIALS AND METHODS: The influence of calcitriol on the proliferation and the effects of calcitriol on the expression of prostaglandin- and vitamin D-metabolising enzymes were examined in benign and malignant breast cells. RESULTS: Calcitriol inhibited the proliferation of MCF-10F and MCF-7 cells but not of invasive MDA-MB-231 cells and reduced the expression of COX-2 and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in the benign breast cell line MCF-10F. Furthermore, dysregulation in vitamin D-metabolising proteins was detected, especially in MDA-MB-231 cells. CONCLUSION: These results suggest dysregulation of vitamin D metabolism and a lack of a possible influence of calcitriol on the metabolism of prostaglandins in the malignant breast cell lines.

Expression of prostaglandin- and vitamin D-metabolising enzymes in benign and malignant breast cells.

BACKGROUND: Cyclooxygenase-2 (COX-2) plays a crucial role in prognosis of malignancy and has been associated with carcinogenesis, particularly neoangiogenesis and tumor progression. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is described as a tumour suppressor in cancer. The antiproliferative effects of calcitriol [1,25(OH)(2)D(3)] mediated via the vitamin D receptor (VDR) render vitamin D a promising target in breast cancer therapy. MATERIALS AND METHODS: The expression of prostaglandin (PG)-metabolizing enzymes, vitamin D-metabolising enzymes and VDR were determined in benign and malignant breast cell lines using western blot analysis. RESULTS: We detected an inverse correlation between the two types of metabolism, a reduced VDR expression in the malignant breast cell lines, and therefore an insufficient induction of 24-hydroxylase in the malignant cells. CONCLUSION: We suggest the possibility of dysregulation of vitamin D-metabolizing enzymes in malignant breast cell lines.

Follicular fluid high-density lipoprotein-associated sphingosine 1-phosphate (S1P) promotes human granulosa lutein cell migration via S1P receptor type 3 and small G-protein RAC1.

Coordinated migration and progesterone production by granulosa cells is critical to the development of the corpus luteum, but the underlying mechanisms remain obscure. Sphingosine 1-phosphate (S1P), which is associated with follicular fluid high-density lipoprotein (FF-HDL), was previously shown to regulate ovarian angiogenesis. We herein examined the effects of S1P and FF-HDL on the function of granulosa lutein cells. Both FF-HDL and S1P induced migration of primary human granulosa lutein cells (hGCs) and the granulosa lutein cell line HGL5. In addition, FF-HDL but not S1P promoted progesterone synthesis, and neither of the two compounds stimulated proliferation of granulosa lutein cells. Polymerase chain reaction and Western blot experiments demonstrated the expression of S1P receptor type 1 (S1PR1), S1PR2, S1PR3, and S1PR5 but not S1PR4 in hGCs and HGL5 cells. The FF-HDL- and S1P-induced granulosa lutein cell migration was emulated by FTY720, an agonist of S1PR1, S1PR3, S1PR4, and S1PR5, and by VPC24191, an agonist of S1PR1 and S1PR3, but not by SEW2871 and phytosphingosine 1-phosphate, agonists of S1PR1 and S1PR4, respectively. In addition, blockade of S1PR3 with CAY1044, suramine, or pertussis toxin inhibited hGC and HGL5 cell migration toward FF-HDL or S1P, while blockade of S1PR1 and S1PR2 with W146 and JTE013, respectively, had no effect. Both FF-HDL and S1P triggered activation of small G-protein RAC1 and actin polymerization in granulosa cells, and RAC1 inhibition with Clostridium difficile toxin B or NSC23766 abolished FF-HDL- and S1P-induced migration. The FF-HDL-associated S1P promotes granulosa lutein cell migration via S1PR3 and RAC1 activation. This may represent a novel mechanism contributing to the development of the corpus luteum.

Prostaglandin metabolising enzymes and PGE2 are inversely correlated with vitamin D receptor and 25(OH)2D3 in breast cancer.

BACKGROUND: Breast cancer is associated with inflammatory processes based on an up-regulation of cyclooxygenase-2 (COX-2) expression. The antiproliferative effects of calcitriol (1,25(OH)(2)D(3)) mediated via the vitamin D receptor (VDR) render vitamin D a promising target in breast cancer therapy. First data suggest a correlation between vitamin D and prostaglandin metabolism. MATERIALS AND METHODS: We determined the expression of VDR, COX-2, 15-PGDH and the prostaglandin receptors EP(2)/EP(4) in normal and malignant breast tissue by real-time PCR and Western blot analysis, as well as 25(OH)(2)D(3) and PGE(2) plasma levels from healthy and breast cancer patients. RESULTS: Significantly higher COX-2, lower VDR and lower EP(2) and EP(4) receptor protein levels in the malignant tissue and a significantly lower 15-PGDH protein level in normal breast tissue were detected. Breast cancer patients older than 45 years, diagnosed and sampled in the winter time had significantly lower 25(OH)(2)D(3) and higher PGE(2) serum levels. CONCLUSION: The inverse correlation between VDR and both COX-2 and 15-PGDH, as well as between PGE(2) and 25(OH)(2)D(3) levels, suggests a possible link between VDR-associated target genes and prostaglandin metabolism.

Human luteinized granulosa cells secrete apoB100-containing lipoproteins.

Thus far, liver, intestine, heart, and placenta have been shown to secrete apolipoprotein (apo)B-containing lipoproteins. In the present study, we first investigated lipoproteins in human follicular fluid (FF), surrounding developing oocytes within the ovary, as well as in corresponding plasma samples (n = 12). HDL cholesterol within FF correlated well with plasma HDL cholesterol (r = 0.80, P < 0.01), whereas VLDL cholesterol did not, indicating that VLDL in FF might originate directly from the granulosa cells producing FF. Primary human granulosa cells expressed apoB, microsomal triglyceride transfer protein, and apoE, but not the apoB-editing enzyme apobec-1. Using (3)H-leucine, we show that granulosa cells secrete apoB100-containing lipoproteins and that secretion can be stimulated by adding oleate to the medium (+83%). With electron microscopy, apoB-containing lipoproteins within the secretory pathway of human granulosa cells were directly visualized. Finally, we found a positive relationship between apoB levels in FF and improved fertility parameters in a population of 27 women undergoing in vitro fertilization. This study demonstrates that human granulosa cells assemble and secrete apoB100-containing lipoproteins, thereby identifying a novel cell type equipped with these properties. These results might have important implications for female infertility phenotypes as well as for the development of drugs targeting the VLDL production pathway.

Expression of vitamin D receptor (VDR), cyclooxygenase-2 (COX-2) and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in benign and malignant ovarian tissue and 25-hydroxycholecalciferol (25(OH2)D3) and prostaglandin E2 (PGE2) serum level in ovarian cancer patients.

Ovarian carcinomas are associated with increased inflammation which is based upon an up-regulation of inducible cyclooxygenase-2 (COX-2). Moreover, based on our previous published data, the extra-renal vitamin D metabolism seems to be dysregulated in comparison to healthy tissue. In order to gain further insight into the prostaglandin (PG)- and vitamin D-metabolism in ovarian carcinomas, the study aimed to evaluate the expression of the PG metabolising enzymes COX-2 and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) compared to the vitamin D receptor (VDR) in benign and malignant ovarian tissues. Additionally, we determined the 25-hydroxycholecalciferol (25(OH2)D3) serum levels. Expression of VDR, COX-2 and 15-PGDH was determined by Western blot analysis. Serum levels of 25(OH2)D3 and PGE2 were measured by chemiluminescence-based and colorimetric immunoassay. We detected significantly higher expressions of the PG metabolising enzymes 15-PGDH and COX-2 in malignant tissue and PGE2 serum levels were 2-fold higher in tumour patients. Furthermore, we found an inverse correlation to the VDR-expression which was 62.1% lower in malignant tissues compared to that in benign tissues. Surprisingly, we could not detect any differences between the 25(OH2)D3 serum levels in either group (n=20). These data suggest a correlation between PG- and vitamin D-metabolism in ovarian carcinomas.

Expression of prostaglandin metabolising enzymes COX-2 and 15-PGDH and VDR in human granulosa cells.

BACKGROUND: Prostaglandins (PGs) within the periovulatory follicle are essential for various female reproductive functions such as follicular development and maturation. In animal models, granulosa cells express the PG synthesizing enzyme cyclooxygenase-2 (COX-2) and the PG inactivating enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH). First references suggest a correlation between vitamin D and prostaglandin metabolism through the impact of 1,25(OH)2D3 (calcitriol) on the expression of COX-2 and 15-PGDH. MATERIALS AND METHODS: The expression of COX-2, 15-PGDH and the vitamin D receptor (VDR) in human granulosa cells (COV434, hGC and HGL5), which were originally isolated from different stages of follicular maturation, was determined by real-time PCR (RT-PCR) and Western blot analysis. RESULTS: A positive correlation of COX-2 and VDR protein was found in the COV434 and HGL5 cells and an inverse correlation of 15-PGDH and VDR protein levels in all the investigated cell types. CONCLUSION: There may be a link between VDR, associated target genes and prostaglandin metabolism in human follicular maturation and luteolysis.

Prostaglandin metabolizing enzymes in correlation with vitamin D receptor in benign and malignant breast cell lines.

BACKGROUND: The antiproliferative effects of calcitriol (1,25(OH)2D3) mediated via the vitamin D receptor (VDR), render the biologically active form of vitamin D a promising target in breast cancer therapy. Furthermore, breast cancer is associated with inflammatory processes based on an up-regulation of cyclooxygenase-2 (COX-2) expression, the prostaglandin E2 (PGE2) synthesizing enzyme. The PGE2 metabolizing enzyme, 15-hydroxyprostaglandin dehydrogenase (15-PGDH) is described as a tumor suppressor in cancer. First references suggest a correlation between vitamin D and prostaglandin metabolism through the impact of 1,25(OH)2D3 on the expression of COX-2 and 15-PGDH. MATERIALS AND METHODS: The expression of VDR, COX-2 and 15-PGDH in benign MCF-10F and malignant MCF-7 breast cells was determined by real-time PCR (RT-PCR) and Western blot analysis. RESULTS: Although the RT-PCR data were divergent from those obtained from the Western blot analysis, the COX-2 protein expression was MCF-7 2-fold higher in the MCF-7 compared to the MCF-10F cells. Moreover, a correlation of 15-PGDH to VDR by RT-PCR was found in both cell lines. The VDR protein levels were inversely correlated to the 15-PGDH protein levels and revealed that the MCF-10F cells had the highest VDR expression. CONCLUSION: A possible link between VDR-associated target genes and prostaglandin metabolism is suggested.

25-Hydroxyvitamin D3 1alpha-hydroxylase splice variants in benign and malignant ovarian cell lines and tissue.

Calcitriol is judged to have a positive effect on control of the immune system, cell growth and differentiation and therefore, the prevention of cancer genesis. The aim of this study was to detect any possible differences in the 25-hydroxyvitamin D-1alpha-hydroxylase (1alphaOHase)-expression between benign and malignant ovarian tissue and cell lines. The analysis was conducted quantitatively, by means of nested "touchdown" PCR and Western blot, and qualitatively, with the use of real-time PCR and Western blot. The gene structure was sequenced. Compared to the benign cell line, the malignant cell lines showed a significantly higher expression of 1alphaOHase at the RNA level. A statistically lower expression of the 1alphaOHase protein was found in the malignant tissue. In the malignant cell lines and tissues, divergent bands were detected, which led to various splice variants on sequencing. Their increased expression in malignancy is possibly bound to the reduction of enzyme activity, which may lead to the genesis of ovarian cancer. In the future, preventive and therapeutic activities may result from these findings.

Expression of 25-hydroxyvitamin D3-24-hydroxylase in benign and malignant ovarian cell lines and tissue.

Calcitriol (1,25-dihydroxyvitamin D3, 1,25(OH)2D3) plays a pivotal role in maintaining calcium and phosphate homeostasis. Aside from that, it supports the native and attenuates the acquired immune system and has positive effects on cell growth, differentiation and the prevention of carcinogenesis. The goal of this study was to detect possible differences in the expression of the calcitriol-degrading enzyme 24-hydroxylase (24-OHase) between malignant and benign ovarian cell lines and tissue. The analyses were based on real-time PCR, nested touchdown PCR and Western blot. When compared to benign granulose GLZ cells, the malignant HGL5 cells showed a significantly higher 24-OHase expression at the protein level (p<0.01). In the malignant ovarian tissue, the expression was significantly higher in RNA (p<0.001), but lower at the protein level (p<0.01). An increased 24-OHase expression could indicate a decrease in available calcitriol.

Expression of 25 hydroxyvitamin D3-1alpha-hydroxylase in human endometrial tissue.

1,25(OH)(2)D(3) (calcitriol) has been shown to play an important role in cell proliferation, differentiation and immune responsiveness. The enzyme responsible for calcitriol synthesis 25 hydroxyvitamin D(3)-1alpha-hydroxylase (1alpha-OHase) has been reported in many human tissues. The aim of this study was to investigate the expression of 1alpha-OHase in gynaecological tissues. Using a highly specific nested touchdown PCR we examined the expression of 1alpha-OHase in normal and malignant endometrial tissue and in human endometrial Ishikawa cells. In addition, we analyzed the protein expression of 1alpha-OHase by Western blot. The expression of 1alpha-OHase in normal and malignant endometrial tissue and Ishikawa cells was detected and splice variants of the enzyme in Ishikawa cells were identified. These data suggest an alternative splicing of 1alpha-OHase in malignant endometrial tissue and cells. We postulate that the expression of 1alpha-OHase gene variants may contribute to the antiproliferative effects of calcitriol. In conclusion, the modulation of the 1alpha-OHase opens up a new target for vitamin D(3) related therapies in endometrial cancer.

Follicular fluid high density lipoprotein-associated sphingosine 1-phosphate is a novel mediator of ovarian angiogenesis.

Angiogenesis plays an important role in the development of the ovarian follicle and its subsequent transition into the corpus luteum. Accordingly, follicular fluid is a rich source of mitogenic and angiogenic factors such as basic fibroblast growth factor and vascular endothelial growth factor secreted by granulosa cells. In the present study, we show that follicular fluid deprived of basic fibroblast growth factor or vascular endothelial growth factor by means of thermal denaturation or antibody neutralization retains its capacity to stimulate endothelial proliferation and angiogenesis. Mass spectrometric analysis of chromatographic fractions stimulating endothelial growth obtained from follicular fluid revealed that the heat-stable mitogenic activity is identical with the subfraction alpha of high density lipoproteins purified from follicular fluid (FF-HDL). Further investigations demonstrated that sphingosine 1-phosphate (S1P), one of the lysophospholipids associated with HDL, accounts for the capacity of this lipoprotein to stimulate endothelial growth and the formation of new vessels. Activation of mitogen-activated protein kinase (p42/44(ERK1/2)), protein kinase C, and protein kinase Akt represent signaling pathways utilized by FF-HDL and S1P to induce endothelial proliferation and angiogenesis. We conclude that FF-HDL represents a novel mitogenic and angiogenic factor present in follicular fluid and that S1P is one of the FF-HDL lipid components accounting for this activity.