Interleukin 1 receptor antagonist polymorphism in women with idiopathic recurrent miscarriage

OBJECTIVE

Proinflammatory cytokines have been described as etiologic factors in idiopathic recurrent miscarriage. We investigated the relation between idiopathic recurrent miscarriage and polymorphisms in the gene encoding for the interleukin 1 receptor antagonist, an indigenous modulator of proinflammatory immune response.

DESIGN

Prospective case control study.

SETTING

Academic research institution.

PATIENT(S)

One hundred five women with a history of three or more consecutive pregnancy losses before 20 weeks of gestation and 91 healthy, postmenopausal controls with at least two live births and no history of pregnancy loss.

INTERVENTION(S)

Peripheral venous puncture.

MAIN OUTCOME MEASURE(S)

Polymerase chain reaction was performed to identify the different alleles of the gene encoding for interleukin 1 receptor antagonist.

RESULT(S)

Allele frequencies among women with idiopathic recurrent miscarriage and controls were 0.34 and 0.11, respectively, for the polymorphic allele 2 (P=.002; odds ratio: 7.4, confidence interval: 2.9--10.8) and.05 and.05, respectively, for the polymorphic allele 3 (P=.6; odds ratio: 1.3, confidence interval: 0.8--2.3). Allele 2 was present in homozygous form in 9% of women with idiopathic recurrent miscarriage. In contrast, 1% of the control women were homozygous for this allele (P<.001; odds ratio: 13.5, confidence interval: 7.5--21.8).

CONCLUSION(S)

These data support a role for allele 2 of the gene encoding for interleukin 1 receptor antagonist as genetic determinant of idiopathic recurrent miscarriage.

[The role of nitric oxide in reproduction]

Nitrix oxide (NO) is a highly reactive and short-lived radical (half-life time: 10-12 s), which is derived from L-arginine by the NO synthases (NOS) in several organ systems. The release of NO by endothelial cells leads to rapid relaxation of vascular smooth muscle cells, whereas release by several neuronal cells causes neurotransmission. When NOS is actively induced in immune cells or certain epithelia it causes cytotoxicity and/or apoptosis of these cells. In the reproductive organs NO is now considered to be an important trigger molecule for several physiological mechanisms. Follicular synthesized NO is involved in rupture of the follicle during ovulation. Moreover, NO participates in the acrosome reaction of spermatozoa during capacitation. Apoptosis and collagenolysis of the functional endometrium may be involved in endometrial shedding during menstruation. Since NO induces both apoptosis and collagenolysis, the newly discovered production of NO in late secretory endometrium could act as a key mechanism in the process of menstrual disintegration of the endometrium. Additionally, NO is necessary to support and maintain the decidualization process and plays a pivotal role in implantation.

Melatonin in postmenopausal females

There is little information about the interaction between melatonin, sexual steroids and neuroendocrine system in postmenopausal females, even if former research showed that melatonin is clearly involved in human physiology and pathophysiology. We evaluated the overnight urinary excretion of 6-sulfatoxymelatonin (6-SMT) using a radioimmunoassay in 60 postmenopausal women. The group has been divided into patients with insomnia (10), hyperprolactinemia (7), depression (9), obesity (7) and controls (27). Compared to controls 6-SMT values were significantly higher in depressive females. Patients with hyperprolactinemia showed a trend toward a significantly elevated average nocturnal melatonin concentration. Melatonin levels were significantly lower in patients with insomnia and obese postmenopausal females than in controls. Since previous studies described lower melatonin levels in postmenopausal than in premenopausal women, the indication of melatonin therapy, especially for sleep disorders in this collective, can be handled more generously. Melatonin should be prescribed restrictively in patients with depression and in those with hyperprolactinemia. The role of melatonin in obese females remains unclear.

Endocrinological disorders. Focusing on melatonin's interactions

BACKGROUND

The interaction of melatonin to sterility and anovulation as well as related hormonal disorders has not been sufficiently examined yet. We set out to investigate the interaction between melatonin and hyperprolactinemia, hyperandrogenemia, hypothyreosis and obesity in premenopausal females.

METHODS

We evaluated the overnight urinary excretion of 6-sulfatoxymelatonin (6-SMT) in a group of 155 women using a radioimmunoassay.

RESULTS

Melatonin levels in patients with hyperprolactinemia and hyperandrogenemia with normal body mass index are significantly higher compared to matched controls. Obese females without hormonal disorders showed statistically lower 6-sulfatoxymelatonin levels and in hypothyreotic females we found no difference in 6-sulfatoxymelatonin levels compared to controls.

CONCLUSION

Melatonin plays an important role in patients with hormonal disorders such as hyperprolactinemia and hyperandrogenemia. Melatonin should be prescribed restrictively in all sterile patients. In patients with untreated hypothyreosis or obesity, melatonin seems to play a minor part; in those with hyperprolactinemia and hyperandrogenemia additionally to standard sterility treatment light therapy may improve the outcome.

Expression of inducible nitric oxide synthase in human breast cancer depends on tumor grade

Expression of inducible nitric oxide synthase (iNOS) by tumor cells has been suggested to abrogate metastasis in several tumor models, whereas constitutive NOS expression correlated positively with tumor grade in human breast carcinoma. Whether or not expression of one of the various NOS isoforms could predict the prognosis of breast cancer, however, has not been established. In the present report we investigated the cellular distribution of NOS isoforms in a series of benign and malignant breast tumors and in normal breast tissue. Immunohistochemistry revealed that in samples of benign disease the number of iNOS+ epithelial cells or total epithelial cells was 69+/-16% (n = 50). In samples of grade II invasive ductal breast carcinomas the number of iNOS+ tumor cells or total tumor cells was 62+/-20% (n = 40), compared to 12+/-9% (n = 40) in samples of grade III carcinomas (P<0.0001). iNOS protein was also identifiable in most of the epithelial cells of normal breast tissue (n = 4). In contrast, eNOS protein was restricted to vascular endothelial cells in all of the specimens studied. Since the presence of tumor cell iNOS protein is inversely related to the tumor's metastatic potential, we conclude that endogenous tumor cell mediated iNOS expression might have an inhibitory effect on the metastatic process in breast cancer.

Association of in vitro invasiveness and gene expression of estrogen receptor, progesterone receptor, pS2 and plasminogen activator inhibitor-1 in human breast cancer cell lines

The invasive potential of tumor cells is usually tested either by in vitro invasion assays which evaluate cell spreading ability in basement membrane-like matrices or by in vivo invasion assays in nude mice. Both methods are laborious and time-consuming. Tumor invasiveness is accompanied by the changes in expression of various genes. The invasive behavior of cells is therefore represented by certain gene expression patterns. The purpose of this study was to investigate whether expression patterns of several genes are characteristic for the invasiveness of cultured cells. We examined the mRNA levels of estrogen receptor (ER), progesterone receptor (PR), estrogen inducible pS2 and plasminogen activator inhibitor-1 (PAI-1) in 23 cell lines derived from benign and malignant breast tissues using a competitive reverse transcription-polymerase chain reaction (cRT-PCR) system. We also evaluated the invasiveness of these cell lines by their ability to penetrate into a collagen-fibroblast matrix. We demonstrate that the gene expression pattern of breast cell lines is clearly associated with their in vitro invasiveness. In general, cells with ER, PR, pS2 but no PAI-1 expression showed a non-invasive phenotype, while cells expressing PAI-1 mRNA but not ER mRNA are invasive. Our study indicates that the invasiveness of breast cancer cell lines is characterized by PAI-1 gene expression and the lack of ER mRNA. This suggests that PAI-1 may participate in the invasive process.

Human cervical ripening is associated with an increase in cervical inducible nitric oxide synthase expression

The mechanisms that ultimately regulate cervical ripening during parturition remain largely unknown. A possible role for nitric oxide (NO) has recently emerged; however, the expression of NO synthase (NOS) within the human cervix in the ripening process has not been investigated. The purpose of this study was to identify cell types in the human cervix that contain NOS isoforms and to examine changes in their expression during the ripening process and the nonpregnant state. Inducible NOS (iNOS) immunoreactivity was observed in the epithelial cells and stromal spindle cells in 17 of 20 biopsies from cervices obtained within 10 min postpartum, but in only 4 of 12 nonpregnant controls (p = 0.03). Endothelial NOS (eNOS) immunoreactivity was restricted to vascular endothelia in all sections, whereas neuronal NOS was not detectable. Inducible NOS activity in the postpartum group was 3.2 times that of the control group (p = 0.0005), whereas constitutive NOS activity remained unchanged in both groups (p = 0.222). Competitive reverse transcription-polymerase chain reaction revealed no differences in the expression of iNOS (p = 0.443) or eNOS mRNA (p = 0.409). The existence of iNOS in the human postpartum cervix suggests that increased production of NO, probably induced by cytokines, may be relevant to the process of natural cervical ripening in humans.

Messenger RNA determination of estrogen receptor, progesterone receptor, pS2, and plasminogen activator inhibitor-1 by competitive reverse transcription-polymerase chain reaction in human breast cancer

Estrogen receptor (ER), progesterone receptor (PR), the estrogen-inducible protein pS2, and plasminogen activator inhibitor-1 (PAI-1) are important prognostic factors in primary breast cancer. The protein concentrations of these factors in breast tumors have been well documented. However, few data about the mRNA expression of ER, PR, pS2, and PAI-1 in breast cancer are available, which is mostly due to the limitations of conventional techniques for mRNA analysis. We have described a competitive reverse transcription-PCR system for the simultaneous quantification of ER, PR, pS2, and PAI-1 mRNA in tumor samples. Here, we evaluated 100 tumor biopsies from breast cancer patients for the mRNA expression of ER, PR, pS2, and PAI-1. The results were analyzed for correlations with protein status and with clinical data. Significant correlations between mRNA expression levels and protein concentrations of all tested markers were found. In only a few cases was there an obvious discordance between the measurable amounts of mRNA and protein, especially for ER and PR. In addition, ER, PR, and pS2 mRNA levels correlated significantly with each other. No correlation between PAI-1 mRNA amount and the expression of the other markers was found. With respect to clinical data, ER and PR mRNA levels were found to be inversely correlated to tumor size and histological grade but not to the lymph node status. pS2 and PAI-1 mRNA expression were not correlated with tumor size, grade, or lymph node involvement. In conclusion, competitive reverse transcription-PCR may be used as an alternative for the study of prognostic factors in human breast cancer and other malignancies. However, before mRNA expression is measured for diagnostics, a presumed concordance of mRNA and protein expression must be evaluated very carefully for every gene.

Inducible nitric oxide synthase (iNOS) expression may predict distant metastasis in human melanoma

Expression of inducible nitric oxide synthase (iNOS) and its cellular localization was investigated in subcutaneous or lymph node metastases of human melanoma. Immunohistochemistry revealed that iNOS expression was limited to melanoma cells. In samples of patients without distant metastases, the number of iNOS+ tumour cells/total tumour cells was 55% +/- 17% (n = 12) compared with 9% +/- 8% when distant metastases of lung, liver or brain occurred within an observation period of 3 years (n = 10) (P < 0.001). Western blotting confirmed the expression of iNOS protein in select cases. Notably, iNOS is expressed in regional melanoma metastases and its expression is inversely related to the tumour's metastatic potential. Thus, iNOS expression may have predictive value for the development of distant metastases of human melanoma.

Elevation of inducible nitric oxide synthase activity in human endometrium during menstruation

Nitric oxide (NO) is a known agonist of programmed cell death (apoptosis). In order to discover its potential role during menstrual shedding, a process associated with extensive apoptosis, we evaluated activity and mRNA levels of the inducible and constitutive isoforms of NO synthase (NOS) in endometrial specimens of the proliferative (n = 11), late-secretory (n = 7), and menstrual (n = 17) phase of the cycle. These levels were compared with the proportion of apoptotic cells by detection of histochemically labeled DNA fragments. Inducible NOS (iNOS) activity during menstruation was six times that of the proliferative or late-secretory phase (p < 0.05), whereas constitutive NOS activity remained unchanged. Competitive reverse transcription-polymerase chain reaction revealed 146% and 77% increases of iNOS mRNA expression in the late-secretory and menstrual phases, respectively, compared to the proliferative phase (p < 0.05), whereas constitutive NOS mRNA expression remained constant. Inducible NOS immunostaining was restricted to epithelial cells, whereas constitutive NOS immunostainig was confined to vascular endothelia. In addition, the proportion of apoptotic cells within the glands of late-secretory or menstrual endometrium was twice that of the proliferative phase (p < 0.05). We conclude that local production of NO is involved in the signal transduction mechanisms leading to endometrial breakdown during menstruation.

Oxytocin and vasopressin 1a receptor gene expression in the cycling or pregnant human uterus

OBJECTIVE

Our purpose was to compare concentrations of messenger ribonucleic acid specific for the oxytocin receptor and for the vasopressin 1a receptor in myometrial and endometrial tissues of pregnant and nonpregnant women.

STUDY DESIGN

Tissues from pregnant uteri were obtained from 95 women who were undergoing cesarean delivery between 26 and 42 weeks' gestation. Tissues from nonpregnant uteri were obtained from 7 cycling women who were undergoing hysterectomy. The competitive reverse-transcription polymerase chain reaction method was used to determine messenger ribonucleic acid concentrations.

RESULTS

A significant increase in oxytocin receptor messenger ribonucleic acid was found during the first half of pregnancy. Oxytocin receptor messenger ribonucleic acid concentrations were lower in tissues with spontaneous contractions than in quiescent tissues and were decreased in patients with advanced labor. Vasopressin 1a receptor messenger ribonucleic acid concentrations were high in tissues from both cycling and pregnant uteri but remained unchanged throughout gestation.

CONCLUSION

The increase in oxytocin receptor protein concentrations seen in pregnancy is only partially controlled by messenger ribonucleic acid abundance. High concentrations of vasopressin 1a receptor messenger ribonucleic acid confirm the biologically active role of this receptor in both the cycling and the pregnant uterus.

Expression of endothelial (type III) nitric oxide synthase in cytotrophoblastic cell lines: regulation by hypoxia and inflammatory cytokines

Expression of endothelial nitric oxide synthase (eNOS) has been localized to the villous syncytiotrophoblasts suggesting that NO release from these cells could prevent platelet adhesion and aggregation in the intervillous space. Hypoxia- or inflammation-dependent changes in the release of this vasoactive substance may result in thrombus formation and altered vascular resistance which occur in the placental bed of pre-eclamptic patients. To evaluate the influence of low-oxygen tension and inflammation on eNOS production in the trophoblast steady-state eNOS mRNA and protein levels were investigated in cytotrophoblastic BeWo and Jeg-3 cells cultured at 3.5 per cent oxygen and/or in the presence of the pro-inflammatory cytokines IL-1 and TNF-alpha. By RT-PCR and immunocytochemistry we demonstrate that BeWo cells produce eNOS mRNA and protein while eNOS polypeptide was undetectable in JEG-3 cells. In BeWo cells addition of both cytokines decreases eNOS mRNA and protein abundancies within 24 h of incubation while each substance alone had no effect. Compared to controls, the amount of eNOS transcripts was found to be elevated at low-oxygen tension, however, cNOS protein was downregulated after 24 h in the hypoxic environment, as shown by immunocytochemistry and Western blot analysis. Forskolin and methotrexate, which induce biochemical differentiation/ growth arrest in choriocarcinoma cells, stimulate eNOS mRNA and protein synthesis, but cannot overcome the decline of eNOS polypeptide levels during hypoxic incubation. It is speculated that acute hypoxia and inflammation impair eNOS/NO production of the trophoblast in vivo, which might contribute to pathological conditions of gestational diseases.

M3/M21 serum levels in women with adnexal masses and inflammatory diseases

The aim of the present study was to evaluate the clinical usefulness of the cytokeratin tumor marker M3/M21 as a screening marker for ovarian cancer, as a predictive marker in patients with adnexal masses and as a prognostic factor in women with ovarian cancer. To determine the specificity of the M3/M21 test, we investigated M3/M21 serum levels in several benign conditions. This retrospective study comprises 37 patients with ovarian cancer FIGO stages Ia to III. Sera of patients with benign cysts, endometriosis, pelvic inflammatory disease, inflammatory bowel disease and liver cirrhosis were evaluated in 90, 10, 38, 10 and 20 cases, respectively. With a sensitivity of 57% and a specificity of 95%, M3/M21 is not suitable as a screening marker for ovarian cancer. Although M3/M21 is able to discriminate between ovarian cancer and benign adnexal tumors (univariate logistic regression, p = 0.0003), M3/M21 does not provide information additional to CA 125. M3/M21 serum levels are elevated in several benign conditions such as liver cirrhosis and inflammatory bowel disease. In ovarian cancer patients, elevated M3/M21 serum levels prior to therapy were associated with poor overall and disease-free survival (log-rank test, p = 0.03; log-rank test, p = 0.01, respectively). M3/M21, while obviously not suitable for screening or differential diagnosis of adnexal masses, could be useful as an additional prognostic factor in ovarian cancer patients.

Nitric oxide synthases in Kaposi's sarcoma are expressed predominantly by vessels and tissue macrophages

Kaposi's sarcoma (KS) is a tumor of presumed vascular origin frequently found in patients with AIDS. Recent data suggest that the development of KS is linked with the presence of a newly recognized herpesvirus, human herpesvirus type 8. Nitric oxide (NO), a messenger molecule with vasoactive, antitumor, and antimicrobial effects, is produced by three isoforms of nitric oxide synthases (NOS). In the present report, we investigated the expression of NOS isoforms in KS. By NADPH-diaphorase histochemistry, NOS activity was detectable in endothelia and CD45+ cells within KS lesions. Reactivity for endothelial NOS (eNOS) was found in blood vessel endothelia; however, eNOS reactivity was negative in KS spindle cells in 12 of 17 tumors, and moderately positive in the other 5 lesions. In contrast to KS, tumor cells in three hemangiomas and one angiosarcoma were strongly positive for eNOS. Inducible NOS (iNOS) was absent from KS tumor cells but was found regularly in CD45+, HLA-DR+ cells within the lesions. In five KS-derived spindle cell cultures, neither eNOS nor iNOS proteins were detectable. The sporadic expression of eNOS by KS spindle cells in vivo and the absence of eNOS protein from KS spindle cells in tissue cultures argue against the possibility that the cells are derived from blood vessel endothelia. The consistent expression of iNOS by CD45+, HLA-DR+ cells within KS lesions strongly suggests that leukocyte-derived NO participates in the pathology of this tumor.

A differential PCR system for the determination of CCND1 (cyclin D1) gene amplification in head and neck squamous cell carcinomas

The gene for Cyclin D1 (CCND1) lies within chromosomal region 11q13 and codes for a cell cycle regulator essential for G1 phase progression. This G1-cyclin is a putative protooncogene whose clonal rearrangement and/or amplification and mRNA overexpression occurs in several types of human neoplasias, including head and neck squamous cell carcinomas. Data from the literature suggest that amplification and overexpression of the CCND1 gene could lead to destabilisation of cell cycle control mechanisms and uncontrolled cell proliferation. We developed a differential PCR system for the determination of CCND1 gene amplification in head and neck squamous cell carcinomas. A 115 bp CCND1 fragment and a 150 bp gamma-interferon fragment are amplified simultaneously in the same reaction tube under optimized conditions. Statistical analysis of amplification data obtained by differential PCR revealed excellent correlation with amplification data obtained by conventional Southern hybridization.

Induction of inducible nitric oxide synthase expression in human secretory endometrium

The endometrial secretory phase is characterized by stromal oedema, a premenstrual increase in stromal macrophages and an increased cytokine production as menstruation approaches. Nitric oxide (NO) is a mediator of vasodilatation and cytotoxicity which is synthesized from L-arginine by NO synthases (NOS). These enzymes are either constitutively expressed or induced by lipopolysaccharides and/or cytokines. The presence and function of the inducible isoform of NOS (iNOS) in normal human endometrium has not been fully elucidated until recently. Frozen tissue sections taken from 22 women who underwent hysterectomy and adnexectomy for benign disease were immunostained with antibodies raised against the different NOS isoforms to investigate the presence of NOS in human endometrium. iNOS stained positive in the glandular epithelial cells of the secretory endometrium. Staining was either weak or absent in the proliferative and inactive endometrium, as well as in the oviduct and the glandular epithelium of the endocervix. The stroma remained uniformly negative. Immunoreactivity for endothelial constitutive NOS (eNOS) was confined exclusively to endothelial cells. Furthermore, epithelial cells from endometrium, oviduct and endocervix and all endothelial cells showed positive staining for reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase, which is a histochemical marker for NOS activity. Reverse transcriptase polymerase chain reaction (RT-PCR) was performed in order to assess the presence of NOS mRNA. Abundant expression of iNOS mRNA was detected in the secretory phase endometrium only. The strong expression of inducible NO synthase in human secretory phase endometrium suggests that the increased production of NO, probably induced by cytokines, may be relevant to the process of menstruation.

[6-sulfatoxymelatonin in women with secondary amenorrhea]

We evaluated the overnight urinary excretion of 6-sulfatoxymelatonin in a group of 347 women (range: 18-69 years). 26 women (range 20-29 years) with normogonadotrophic, hypoestrogenemic amenorrhoea (WHO II) were selected and compared with a group of 26 women menstruating normally (range: 19-30 years) with respect to urinary 6-sulfatoxymelatonin excretion, serum 17 beta-estradiol levels and response to the thyroid releasing hormone (TRH) test. Patients with hyperprolactinemia, hyperandrogenemia, thyroid dysfunction and weight problems were excluded. 6-sulfatoxymelatonin was found to be significantly higher in the amenorrhoeic women than in the controls (p < 0.000001). In the amenorrhoeic patients a statistically significant inverse correlation was found between serum 17 beta-estradiol levels and urinary 6-sulfatoxymelatonin excretion. A positive correlation was obtained between the thyroid stimulation hormone (TSH) value measured at 20 minutes after stimulation and 6-sulfatoxymelatonin excretion. Further clinical research in this field is required to evaluate its clinical impact, especially in patients with secondary amenorrhea.

Quantitative determination of gene expression by competitive reverse transcription-polymerase chain reaction in degraded RNA samples

Quantitative competitive reverse transcription-polymerase chain reaction has become a powerful tool for determining the amount of mRNA in cultured cells as well as in tissue. To ensure the reliability of the analysis, RNA with high purity and integrity is needed. However, when analyzing RNA samples from tumor biopsies, RNA degradation is often an inevitable problem. This causes differences in sample quality and furthermore adversely affects the quantification of gene expression. Here, we demonstrate that in partially degraded RNA samples different mRNAs are degraded to the same extent. Normalizing the expression level of a specific gene to that of a constitutively expressed gene in the same sample allows the relative quantification of this specific gene. Thus, the comparison of gene expression in RNA samples with varying integrity is possible.

Estrogen does not induce the calcium-dependent nitric oxide synthase in cultured human uterine endothelial and myometrial smooth muscle cells

In many tissues, estrogen-induced vasodilatation is mediated, at least in part, by the release of nitric oxide (NO). We determined whether human myometrial endothelial and smooth muscle cells express estrogen receptors (ERs) and whether endothelial NO synthase (eNOS) expression in these cells was affected by 17beta-estradiol (10[-13]-10[-6]M). ER was strongly expressed in myometrial smooth muscle cells but was absent from endothelial cells. Expression of eNOS mRNA was strong in endothelial cells, but weak in muscle cells. 17beta-estradiol administration for 24 or 72 h failed to increase eNOS in both cell types. Thus, an increase of human uterine blood flow by estrogens appears not to be mediated by stimulation of myometrial eNOS expression.

Detection of p53 point mutations in primary human vulvar cancer by PCR and temperature gradient gel electrophoresis

Clinical and experimental evidence is consistent with a key role of point mutations of the p53 tumor suppressor gene in the etiology of squamous cell carcinoma. To determine the relation of tumor behavior and patient survival in vulvar cancer in regard to p53 status, we retrospectively analyzed 38 paraffin-embedded specimens of primary vulvar cancer for genetic alterations of exons 5-8 of the p53 gene. For detection of p53 point mutations we used in vitro amplification by polymerase chain reaction (PCR) and temperature gradient gel electrophoresis (TGGE) and, as a detection method, direct sequencing for mutation verification. p53 point mutations were detected in 12/38 tumor specimens. Patients bearing p53 point mutations showed a significantly shorter relapse-free (log-rank test, P = 0.002) and overall survival time (log-rank test, P = 0.0006). We conclude that PCR-TGGE is an appropriate method for detection of p53 point mutations in paraffin-embedded material. We show that loss of wild-type p53 is an adverse prognostic factor in patients suffering from vulvar cancer.

Quantification of uPA receptor expression in human breast cancer cell lines by cRT-PCR

The conversion of plasminogen to active plasmin is thought to be a crucial step in the process of extracellular matrix degradation associated with metastatic spread. Activation of plasminogen is initiated by urokinase plasminogen activator (uPA). The binding of uPA to the uPA cell surface receptor (uPA-R) accelerates plasmin generation from plasminogen and localizes uPA activity to the cell surface. We investigated the mRNA-expression of uPA-R in 19 different human breast cancer cell lines. In a competitive reverse transcription polymerase chain reaction (cRT-PCR) we simultaneously co-amplified two different RNA templates bearing the same primer recognition sequences, the cell line RNA and a known amount of an in vitro synthesized uPA-R-RNA internal standard. We analyzed the two PCR products differing 50 bp in size by agarose gel electrophoresis and calculated the initial uPA-R-RNA template concentration from the relative intensities of the bands quantified by video densitometry. We grouped the investigated cell lines according to their in vitro invasiveness according to literature. Cell lines with a high potential of invasiveness showed a higher expression of uPA-R compared to those with a low potential of invasiveness (Student's t-test, p 0.04). In addition to that we compared the uPA-R mRNA levels with uPA-R, uPA, and PAI-1 protein levels in culture supernatants and cell lysates. The obtained results in breast cancer cell lines with different invasiveness and in benign epithelial cell lines revealed the complex cooperation of the urokinase type proteolytic pathway. uPA, uPA-R, and PAI-1 are to be considered as a diagnostic tool rather than assaying a particular molecule alone. Our findings support the hypothesis that the urokinase proteolytic pathway plays a central role in the acquisition of an invasive phenotype and favors its potential use as a prognostic marker in patients with breast cancer.

Simultaneous expression of nitric oxide synthase and estrogen receptor in human breast cancer cell lines

For various human tumor cell lines (neuroblastoma, cervix carcinoma) the presence of constitutive nitric oxide synthase (cNOS) has been documented. Here, for the first time, we report about cNOS expression in 10 of 16 human breast cancer cell lines. cNOS expression correlates strongly with expression of estrogen receptor (ER). Competitive reverse transcription-polymerase chain reaction (cRT-PCR) was used to detect cNOS and ER mRNA expression. Our findings suggest that estradiol could stimulate constitutive NO release in breast tissue, where it acts as a free radical.

Competitive reverse transcriptase-PCR: an improved method for determination of c-erbB-2 gene expression

The aim of our study was to establish a simple method for routine analysis of c-erbB-2 gene expression in tumour samples. We constructed a plasmid for the in vitro synthesis of competitor RNA to be used as an internal exogenous control during the RT-PCR detection of c-erbB-2 expression. The competitor RNA harbors a 19-base deletion and 63-base insertion compared to wild-type c-erbB-2 mRNA and generates a PCR product which is easily distinguished from the wild-type PCR product by agarose gel electrophoresis. The sensitivity and reliability of our RT-PCR-system was determined. To address this, we measured c-erbB-2 expression in cultured cells, of which c-erbB-2 expression data were available from Northern blot analysis. In conclusion, our experimental strategy correlated well with the results obtained by Northern blot hybridization, however, it overcomes time consuming and expensive procedures used in classical gene expression analysis.

Microdissection as a means to verify allelic imbalance in tumour biology samples

Allelotypes (TP53, AFM051xd10 and alu-i1) in normal DNA and in DNA from paraffin-embedded tumours of a patient with a p53 germ-line mutation were compared in order to demonstrate LOH. Microdissection was applied in order to overcome difficulties with the interpretation of LOH data from a pelvic recurrence of a primary malignant histiocytoma. Furthermore, a rapid and simple boiling method was developed in order to reduce the loss of DNA usually occurring during traditional methods for DNA extraction. The conclusion drawn is that it is of utmost importance to use highly enriched fractions of tumour cells when performing LOH-studies. It is also shown that a rapid and simple boiling procedure is sufficient to release enough DNA of microdissection-enriched tumour cells for microsatellite analysis by PCR to detect allelic imbalance.