Differential gene expression pattern between normal human trophoblast and choriocarcinoma cell lines: downregulation of heat shock protein-27 in choriocarcinoma in vitro and in vivo

Gestational choriocarcinoma

Gestational choriocarcinoma accounts for 5% of gestational trophoblastic neoplasms. Approximately 50%, 25%, and 25% of gestational choriocarcinoma occur after molar pregnancies, term pregnancies, and other gestational events, respectively. The FIGO scoring system categorizes patients into low (score 0 to 6) and high risk (score 7 or more) choriocarcinoma. Single-agent and multi-agent chemotherapy are used in low- and high-risk patients, respectively. Chemotherapy for localized disease has a goal of eradication of disease without surgery and is associated with favorable prognosis and fertility preservation. Most patients with gestational choriocarcinoma are cured with chemotherapy; however, some (<5.0%) will die as a result of multi-drug resistance, underscoring the need for novel approaches in this group of patients. Although there are limited data due to its rarity, the treatment response with immunotherapy is high, ranging between 50-70%. Novel combinations of immune checkpoint inhibitors with targeted therapies (including VEGFR-2 inhibitors) are under evaluation. PD-L1 inhibitors are considered a potential important opportunity for chemo-resistant patients, and to replace or de-escalate chemotherapy to avoid or minimize chemotherapy toxicity. In this review, the Rare Tumor Working Group and the European Organization for Research and Treatment of Cancer evaluated the current landscape and further perspective in the management of patients diagnosed with gestational choriocarcinoma.

Measurement of Human Chorionic Gonadotrophin in Women with Gestational Trophoblastic Disease

OBJECTIVES

The objective of this study was to collect information on human chorionic gonadotrophin (hCG) laboratory testing and reporting in women with gestational trophoblastic disease (GTD), to assess the associated challenges, and to offer perspectives on hCG testing harmonisation.

DESIGN

Information was collected from laboratories by electronic survey (SurveyMonkey) using a questionnaire designed by members of the European Organisation for the Treatment of Trophoblastic Disease (EOTTD) hCG working party.

PARTICIPANTS

The questionnaire was distributed by the EOTTD board to member laboratories and their associated scientists who work within the GTD field.

SETTING

The questionnaire was distributed and accessed via an online platform.

METHODS

The questionnaire consisted of 5 main sections. These included methods used for hCG testing, quality procedures, reporting of results, laboratory operational aspects, and non-GTD testing capability. In addition to reporting these survey results, examples of case scenarios which illustrate the difficulties faced by laboratories providing hCG measurement for GTD patient management were described. The benefits and challenges of using centralised versus non-centralised hCG testing were discussed alongside the utilisation of regression curves for management of GTD patients.

RESULTS

Information from the survey was collated and presented for each section and showed huge variability in responses across laboratories even for those using the same hCG testing platforms. An educational example was presented, highlighting the consequence of using inappropriate hCG assays on clinical patient management (Educational Example A), along with an example of biotin interference (Educational Example B) and an example of high-dose hook effect (Educational Example C), demonstrating the importance of knowing the limitations of hCG tests. The merits of centralised versus non-centralised hCG testing and use of hCG regression curves to aid patient management were discussed.

LIMITATIONS

To ensure the survey was completed by laboratories providing hCG testing for GTD management, the questionnaire was distributed by the EOTTD board. It was assumed the EOTTD board held the correct laboratory contact, and that the questionnaire was completed by a scientist with in-depth knowledge of laboratory procedures.

CONCLUSIONS

The hCG survey highlighted a lack of harmonisation of hCG testing across laboratories. Healthcare professionals involved in the management of women with GTD should be aware of this limitation. Further work is needed to ensure an appropriate, quality-assured laboratory service is available for hCG monitoring in women with GTD.

Myostatin: a multifunctional role in human female reproduction and fertility - a short review

Myostatin (MSTN) is member of the transforming growth factor β (TGF-β) superfamily and was originally identified in the musculoskeletal system as a negative regulator of skeletal muscle growth. The functional roles of MSTN outside of the musculoskeletal system have aroused researchers' interest in recent years, with an increasing number of studies being conducted in this area. Notably, the expression of MSTN and its potential activities in various reproductive organs, including the ovary, placenta, and uterus, have recently been examined. Numerous studies published in the last few years demonstrate that MSTN plays a critical role in human reproduction and fertility, including the regulation of follicular development, ovarian steroidogenesis, granule-cell proliferation, and oocyte maturation regulation. Furthermore, findings from clinical samples suggest that MSTN may play a key role in the pathogenesis of several reproductive disorders such as uterine myoma, preeclampsia (PE), ovary hyperstimulation syndrome (OHSS), and polycystic ovarian syndrome (PCOS). There is no comprehensive review regarding to MSTN related to the female reproductive system in the literature. This review serves as a summary of the genes in reproductive medicine and their potential influence. We summarized MSTN expression in different compartments of the female reproductive system. Subsequently, we discuss the role of MSTN in both physiological and several pathological conditions related to the female fertility and reproduction-related diseases.

miR-26a-5p and miR-125b-5p affect trophoblast genes and cell functions important during early pregnancy†

The most critical stage of pregnancy is embryo implantation, which relies on the synchronised developmental capacity of the embryo and uterine receptivity to implantation. In early pregnancy, conceptus and uterus release several factors enabling successful implantation and placentation. Molecules involved in embryo-maternal crosstalk include, but are not limited to, hormones, growth factors and cytokines. The discovery of microRNAs (miRNAs, small non-coding RNAs regulating gene expression) has revolutionized our understanding of many biological processes, including pregnancy. To date, numerous miRNAs have been detected in different species during pregnancy, both at the endometrial and embryonic sites. Thus, miRNAs are considered important regulators of early pregnancy events. Here, we report miR-26a-5p and miR-125b-5p effects on human and pig trophoblast cell function. Both miRNAs change the level of several genes and proteins important for proper embryo development. Moreover, miR-26a-5p stimulates porcine trophoblast proliferation and has a negative impact on its affinity to laminin. However, miR-125b-5p decreases porcine trophoblast cell migration. Our studies suggest that miR-26a-5p and miR-125b-5p can affect early pregnancy functions by regulating genes and processes important for proper conceptuses' development and progression through the implantation process.

Modelling preeclampsia: a comparative analysis of the common human trophoblast cell lines

Preeclampsia remains a challenge without an effective therapy. Evidence supports targetability of soluble fms‐like tyrosine kinase‐1 (sFlt‐1) and soluble endoglin (sEng), which are released excessively from the placenta under ischemic and hypoxic stresses. We compared four trophoblast cell lines, BeWo, Jar, Jeg‐3, and HTR‐8/SVneo, in order to identify a suitable model for drug screening. Cultured trophoblasts were exposed to 1% oxygen vs. normoxia for 24‐48 hr; human umbilical vein and aortic endothelial cells were included for comparison. Supernatant sFlt‐1 and sEng concentrations were measured by ELISA, and sFlt‐1 mRNA expression determined by RT‐PCR. Cellular responses to experimental therapeutics were explored. All four trophoblast lines secreted sEng, which did not increase by hypoxia. BeWo, Jar, and Jeg‐3 exhibited significantly enhanced expression of sFlt‐1 i13 and e15a mRNA in response to hypoxia; however, only BeWo released a detectable level of sFlt‐1 protein, which was doubled by hypoxia. In contrast, hypoxia decreased sFlt‐1 mRNA expression and protein release in HTR‐8/SVneo, similarly to endothelial cells. The cellular mechanism involved HIFα. BeWo responded to representative agents similarly to human primary placental tissues in the literature. These data support that the BeWo‐hypoxia model mimics a key pathogenic mechanism of preeclampsia and has potential value for translational drug discovery.

Toll-like receptor profiling of seven trophoblast cell lines warrants caution for translation to primary trophoblasts

INTRODUCTION

Excessive placental inflammation is associated with pregnancy complications. Toll-like receptors (TLRs) are sensors for danger signals from infections and damaged tissue and initiate inflammation. Trophoblasts in the placenta broadly express TLRs. Trophoblast cell lines are used as surrogates for primary trophoblasts for in vitro studies, but the inflammatory translatability of trophoblast cell lines warrants examination. We aimed to assess TLR1-10 gene expression and activation in seven trophoblast cell lines and compare this to primary trophoblasts.

METHODS

The five choriocarcinoma trophoblast cell lines BeWo, JAR, JEG-3, AC1M-32 and ACH-3P, and the two SV40 transfected trophoblast cell lines HTR-8/SVneo and SGHPL-5 were included and compared to primary first trimester trophoblasts (n = 6). TLR1-10 gene expression was analyzed by RT-qPCR. Cells were stimulated by specific TLR1-9 ligands for 24 h and cytokine release was measured by a 10-plex immunoassay.

RESULTS

All choriocarcinoma cell lines demonstrated broad TLR gene expression, but lacked functional cytokine response to TLR ligand activation. In contrast, SV40 transfected cell lines showed restricted TLR gene expression, but SGHPL-5 cells displayed significantly increased levels of interleukin (IL)-6, IL-8, IL-12 and vascular endothelial growth factor A after TLR3 and/or TLR4 activation (P < 0.01), while TLR2 activation increased IL-6 and IL-8 levels (P < 0.05). HTR8/SVneo cells responded to TLR3 activation by increased IL-6 and interferon (IFN)-γ (P < 0.05). The SGHPL-5 TLR profile most closely resembled primary trophoblast.

DISCUSSION

The characterized trophoblast cell line TLR profiles serve as a reference and warrant caution when selecting trophoblast cell lines as in vitro models for immune responses in primary trophoblasts.

Dysregulated expression of matrix metalloproteinases and their inhibitors may participate in the pathogenesis of pre-eclampsia and fetal growth restriction

BACKGROUND

Trophoblast invasion into the maternal endometrium serves an important function in human pregnancy. Dysregulation of the finely controlled process of trophoblast invasion can result in a wide spectrum of pregnancy abnormalities.

AIMS

We aimed to elucidate the relationship between the expression of matrix metalloproteinases and pregnancy complication.

STUDY DESIGN

The study group consisted of placental bed biopsy tissues obtained from normal vaginal deliveries (N=15), normal cesarean deliveries (N=15), pre-eclampsia (N=24) and fetal growth restriction (FGR) (N=10). We evaluated the expressions of MMP-2, -8, -9, -11, -19, -15 (MT2-MMP), -16 (MT3-MMP), and -24 (MT5-MMP), as well as TIMP-1 and -3, by applying Western blot and immunohistochemistry methods.

SUBJECTS

Human placental tissues were used for this study.

OUTCOME MEASURES

The expressions of MMP-2, -8, -9, -11, -19, -15 (MT2-MMP), -16 (MT3-MMP), and -24 (MT5-MMP), as well as TIMP-1 and -3 in human placenta tissues.

RESULTS

Compared with those in normal pregnancies, the expression of MMP-2, -8, -9 and -11 was downregulated in villous tissues of pre-eclampsia and FGR cases (p<0.05). TIMP-1 and -3 were increased in pre-eclampsia and FGR (p<0.05). No significant difference was found between normal vaginal deliveries and cesarean deliveries.

CONCLUSIONS

We speculate that the change in invasion-associated proteinase expression will affect placental development and may thus contribute to the development of complicated pregnancies.

The expression and potential functions of placental myostatin

Myostatin (growth differentiation factor-8; GDF-8) is a potent negative regulator of muscle development affecting both proliferation and differentiation. Myostatin has been reported to enhance the release of cytokines, including TNF-α (a pro-inflammatory cytokine involved in implantation). In the human placenta, myostatin production is negatively correlated with gestational age and has been implicated in the control of glucose uptake. Preliminary data indicate its expression is primarily localized to cytotrophoblast and syncytiotrophoblast. The role of myostatin in the placenta, however, remains to be fully elucidated. We speculate that myostatin is key regulator that contributes to placentation and the regulation of placental function throughout pregnancy.

The small heat shock protein alphaA-crystallin is expressed in pancreas and acts as a negative regulator of carcinogenesis

The small heat shock protein alphaA-crystallin is a structural protein in the ocular lens. In addition, recent studies have also revealed that it is a molecular chaperone, an autokinase and a strong anti-apoptotic regulator. Besides its lenticular distribution, a previous study demonstrates that a detectable level of alphaA-crystallin is found in other tissues including thymus and spleen. In the present study, we have re-examined the distribution of alphaA-crystallin in various normal human and mouse tissues and found that the normal pancreas expresses a moderate level of alphaA-crystallin. Moreover, alphaA-crystallin is found significantly downregulated in 60 cases of pancreatic carcinoma of different types than it is in 11 normal human pancreas samples. In addition, we demonstrate that alphaA-crystallin can enhance the activity of the activating protein-1 (AP-1) through modulating the function of the MAP kinase, and also upregulates components of TGFbeta pathway. Finally, expression of alphaA-crystallin in a pancreatic cancer cell line, MiaPaCa, results in retarded cell migration. Together, these results suggest that alphaA-crystallin seems to negatively regulate pancreatic carcinogenesis.

Gestational trophoblastic neoplasia—pathogenesis and potential therapeutic targets

Gestational trophoblastic neoplasia comprises a unique group of human neoplastic diseases that derive from fetal trophoblastic tissues and represent semiallografts in patients. This group is composed of choriocarcinoma, placental-site trophoblastic tumour, and epithelioid trophoblastic tumour, and many forms are derived from the precursor lesions, hydatidiform moles. Although most patients with gestational trophoblastic neoplasia are cured by chemotherapy and tumour resection, some patients suffer from metastatic diseases that are refractory to conventional chemotherapy. Therefore, new therapeutic regimens are needed to reduce the toxic effects associated with current chemotherapy and to salvage the occasional non-operable patients with recurrent and chemoresistant disease. Until the fundamental biology of gestational trophoblastic neoplasia becomes more clearly understood, development of a new treatment will remain empirical. This review will briefly summarise the recent advances in understanding the molecular aetiology of this group of diseases and highlight the molecules that can be potentially used for therapeutic targets to treat metastatic gestational trophoblastic neoplasia.

Heat shock protein 1 and the mitogen-activated protein kinase 14 pathway are important for mouse trophoblast stem cell differentiation

Differentiation of trophoblast cells is a critical process for the proper establishment of the placenta and is, therefore, necessary to maintain embryonic development. Trophoblast stem (TS) cells grown in culture can differentiate into different trophoblast subtypes in vitro mimicking normal trophoblast cell differentiation. Therefore, TS cells are a valuable model system that can be used to elucidate genetic factors that regulate trophoblast cell differentiation. Several transcription factors, when analyzed by targeted gene mutation in mice, have resulted in embryonic lethality due to placental defects and, more specifically, defects of the trophoblast lineages. These studies have helped improve our knowledge about trophoblast cell differentiation, but much is still unknown about the specific mechanisms involved. This study uses TS cell culture to detect proteins with differential expression in proliferating and differentiating TS cells in order to identify proteins with potential roles in the differentiation process. We identified four proteins with differential expression: dimethylarginine dimethylaminohydrolase1 (DDAH1), keratin 8, keratin 18, and HSPB1 (also known as heat shock protein 25, HSP25). Further investigation confirmed the presence of HSPB1 protein during in vitro TS cell differentiation. In addition, we confirmed that phosphorylation of HSPB1 and MAP kinase-activated protein kinase 2 (MAPKAPK2) increased in TS cells during differentiation. Inhibition of MAPK14 (also known as p38 MAPK) resulted in a reduction of HSPB1 phosphorylation and an increase in cell death during TS cell differentiation. These results suggest that HSPB1 and the MAPK14 pathway are important during TS cell differentiation.

Heat shock proteins in cancer: diagnostic, prognostic, predictive, and treatment implications

Heat shock proteins (Hsps) are overexpressed in a wide range of human cancers and are implicated in tumor cell proliferation, differentiation, invasion, metastasis, death, and recognition by the immune system. We review the current status of the role of Hsp expression in cancer with special emphasis on the clinical setting. Although Hsp levels are not informative at the diagnostic level, they are useful biomarkers for carcinogenesis in some tissues and signal the degree of differentiation and the aggressiveness of some cancers. In addition, the circulating levels of Hsp and anti-Hsp antibodies in cancer patients may be useful in tumor diagnosis. Furthermore, several Hsp are implicated with the prognosis of specific cancers, most notably Hsp27, whose expression is associated with poor prognosis in gastric, liver, and prostate carcinoma, and osteosarcomas, and Hsp70, which is correlated with poor prognosis in breast, endometrial, uterine cervical, and bladder carcinomas. Increased Hsp expression may also predict the response to some anticancer treatments. For example, Hsp27 and Hsp70 are implicated in resistance to chemotherapy in breast cancer, Hsp27 predicts a poor response to chemotherapy in leukemia patients, whereas Hsp70 expression predicts a better response to chemotherapy in osteosarcomas. Implication of Hsp in tumor progression and response to therapy has led to its successful targeting in therapy by 2 main strategies, including: (1) pharmacological modification of Hsp expression or molecular chaperone activity and (2) use of Hsps in anticancer vaccines, exploiting their ability to act as immunological adjuvants. In conclusion, the present times are of importance for the field of Hsps in cancer, with great contributions to both basic and clinical cancer research.

Caspase activity is downregulated in choriocarcinoma: a cDNA array differential expression study

BACKGROUND

Placental trophoblast can be considered to be pseudomalignant tissue and the pathogenesis of gestational trophoblastic diseases remains to be clarified.

AIMS

To examine the role of caspases 8 and 10, identified by differential expression, on trophoblast tumorigenesis.

METHODS

cDNA array hybridisation was used to compare gene expression profiles in choriocarcinoma cell lines (JAR, JEG, and BeWo) and normal first trimester human placentas, followed by confirmation with quantitative real time polymerase chain reaction and immunohistochemistry. Caspase 10 and its closely related family member caspase 8 were analysed.

RESULTS

Downregulation of caspase 10 in choriocarcinoma was detected by both Atlastrade mark human cDNA expression array and Atlastrade mark human 1.2 array. Caspase 10 mRNA expression was significantly lower in hydatidiform mole (p = 0.035) and chorioarcinoma (p = 0.002) compared with normal placenta. The caspase 8 and 10 proteins were expressed predominantly in the cytotrophoblast and syncytiotrophoblast, respectively, with significantly lower expression in choriocarcinomas than other trophoblastic tissues (p < 0.05). Immunoreactivity for both caspase 8 and 10 correlated with the apoptotic index previously assessed by terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (p = 0.02 and p = 0.04, respectively) and M30 (p < 0.001 and p = 0.003, respectively) approaches.

CONCLUSIONS

These results suggest that the downregulation of capases 8 and 10 might contribute to the pathogenesis of choriocarcinoma.

Global approach to perinatal medicine: functional genomics and proteomics

Functional genomics (transcriptomics and proteomics) is a global, systematic and comprehensive approach to the identification and description of the processes and pathways involved in normal and abnormal physiological states. The functional genomics methods most applied today are DNA microarrays and proteomics methods, primarily two-dimensional gel electrophoresis coupled with mass spectrometry. To date, interesting research has been carried out, representing milestones for future implementation of functional genomics/proteomics in perinatal medicine. For instance, possible biomarkers of pre-eclampsia, preterm labor and gestational trophoblastic diseases have been discovered. Further systematic examination of differentially regulated genes and proteins in maternal and fetal tissues and fluids will be required. However, high-throughput technologies reflect biological fluctuations and methodological errors. Large amounts of such different data challenge the performance and capacity of the statistical tools and software available at present. Further major developments in this field are pending and the intellectual investment will certainly result in clinical advances.

Mcl-1 expression in gestational trophoblastic disease correlates with clinical outcome

BACKGROUND

Hydatidiform moles (HMs) are abnormal pregnancies with a propensity for developing persistent disease in the form of gestational trophoblastic neoplasia (GTN), which requires chemotherapy. In previous studies, the authors demonstrated that low apoptotic activity was correlated with the progression of HM to GTN, and they hypothesized that some apoptosis-related genes may determine this progression.

METHODS

The differential expression of apoptotic genes in HMs that subsequently developed into GTN was compared with the same expression in HMs that spontaneously regressed using a human apoptosis array; then, the expression was evaluated with real-time quantitative polymerase chain reaction analysis and immunohistochemistry using 54 clinical samples from patients with HMs who had follow-up data available.

RESULTS

Using an apoptosis array, greater expression of Mcl-1, which is an antiapoptotic gene, was detected in HMs that subsequently developed into GTN. It was confirmed that the levels of Mcl-1 RNA expression (P = 0.017) and Mcl-1 protein expression (P < 0.001) in HMs that developed into persistent disease and required chemotherapy were significantly greater compared with the levels in HMs that regressed. Moreover, Mcl-1 immunoreactivity, which was detected predominantly in cytotrophoblasts, was correlated with the apoptotic index, as assessed with M30 cytoDeath immunohistochemistry, which is a good indicator of apoptotic events in the early-stage disease.

CONCLUSIONS

The current results demonstrated that Mcl-1, as identified by a cyclic DNA array, may play a role in the pathogenesis of HMs and may have potential as a useful marker for predicting the clinical behavior of HMs.

The changes of gene expression profiles in hydatidiform mole and choriocarcinoma with hyperplasia of trophoblasts

The purpose of this study is to investigate changes of gene expression profiles in hydatidiform moles (HM) and choriocarcinoma and to explore causes of trophoblastic hyperplasia. Using cDNA microarray, 4,096 genes were analyzed in two pairs of the tissues of HM versus normal villi and in two pairs of normal primary culture trophoblasts versus JAR cell line of choriocarcinoma. The expressions of two genes in normal villi and HM, as well as in JAR and JEG-3, were examined with the help of immunohistochemistry, immunoblot, and reverse transcriptase-polymerase chain reaction in order to confirm the findings of cDNA microarray. Twenty-four genes were upregulated and 65 genes were downregulated in all HM. Four hundred thirty-three genes were upregulated and 380 genes were downregulated in JAR. Forty-six genes were upregulated in both HM and choriocarcinoma, whereas 13 genes were downregulated. Genes associated with the inhibition of cell proliferation were significantly downregulated, whereas genes associated with cell proliferation, malignant transformation, metastasis, and drug resistance were upregulated. Thymidine kinase-1 (TK-1) and small subunit ribonucleotide reductase (RRM-2) were overexpressed in HM, JAR, and JEG-3. The expressions of TK-1 and RRM-2 in moles were positively correlated with proliferative index of trophoblasts. Our results suggest that altered expression of genes exist in HM and choriocarcinoma. Trophoblastic hyperplasia may be involved in the overexpression of DNA synthetic enzymes.

Down-regulation and promoter methylation of tissue inhibitor of metalloproteinase 3 in choriocarcinoma

OBJECTIVE

To assess the differential gene expression in neoplastic and normal trophoblastic cells and evaluate the effect of methylation on tissue inhibitor of metalloproteinase 3 (TIMP3) expression in choriocarcinoma (CCA) cells.

METHODS

The Atlas Human Cancer 1.2 Array (Clontech) was used to compare differential gene expression in a trophoblastic cell line (B6) established from first term placenta with two choriocarcinoma cell lines (JAR and JEG-3). The differentially expressed candidate genes in the placental and malignant trophoblastic cells in these cell lines were confirmed by real-time polymerase chain reaction (PCR), Western blotting and immunohistochemistry. Differential expression of a specific gene, TIMP3, was confirmed by immunohistochemistry using clinical specimens of choriocarcinoma and placenta. The involvement of promoter methylation in suppression of TIMP3 expression in choriocarcinoma was examined using methylation-specific PCR (MSP) and demethylation treatment.

RESULTS

Differential expression of 23 genes was observed in choriocarcinoma cell lines compared to the placental trophoblastic cells using the cDNA array analysis (Atlas Human Cancer Array, Clontech). Among these differentially expressed genes, down-regulation of TIMP3, PLAB, IGFBP3 and up-regulation of CCNB1 were confirmed by real-time PCR determination. Reduced expression of TIMP3 was further confirmed in clinical samples of choriocarcinoma by immunohistochemical staining. Methylation of TIMP3 promoter was detected in choriocarcinoma cell lines and clinical samples of choriocarcinoma. Treatment with a demethylation drug, 5-aza-2'-deoxycytidine, in choriocarcinoma cell lines restored TIMP3 expression.

CONCLUSION

Down-regulation of TIMP3, PLAB, IGFBP3 and up-regulation of CCNB1 were observed in choriocarcinoma cells compared to placental trophoblasts. Down-regulation of TIMP3 expression was confirmed in clinical specimens of choriocarcinoma and may play a role in its pathogenesis. Promoter methylation of the TIMP3 is involved in suppression of TIMP3 expression. Differentiation expression of TIMP3 in choriocarcinoma may have potential application in clinical diagnosis and patient treatment.

Protein profiling of complete mole and normal placenta using ProteinChip analysis on laser capture microdissected cells

INTRODUCTION

Surface-enhanced laser desorption/ionization mass spectrometry (SELDI-MS) is a novel method for biomarker discovery that can provide a rapid protein expression profile from a variety of biological samples. Since SELDI-MS requires a small amount of biological material, this technique is ideal for analyzing proteins isolated from microdissected tissue samples. The current study was undertaken to investigate potential differences in protein expression between normal and molar trophoblast procured by laser capture microdissection (LCM) utilizing SELDI ProteinChip array technology. Further knowledge of protein expression in complete mole may advance our understanding of the pathogenesis of gestational trophoblastic diseases.

MATERIALS AND METHODS

Laser capture microdissected trophoblast cells from nine fresh complete moles were analyzed and compared to the trophoblast cells from 10 fresh normal placentas of comparable gestational age, using SELDI ProteinChip to identify potential differences in protein expression.

RESULTS

Three metal binding polypeptides were identified with the estimated molecular weights of 11.3, 13.8, and 14.0 kDa, which appeared in significantly lower levels in complete mole as compared to normal trophoblast cells (P < 0.001, P < 0.03, and P < 0.01).

DISCUSSION

While further characterization of these protein peaks is important and necessary, our current work clearly demonstrates that the combined technology of SELDI and LCM is effective in distinguishing protein expression between normal placenta and complete mole. Further knowledge of protein expression in complete mole may advance our understanding of molecular mechanisms and improve management in gestational trophoblastic diseases.

Identification of multiple differentially expressed messenger RNAs in normal and pathological trophoblast

In an attempt to assess the molecular basis of phenotypic alterations present in the gestational trophoblastic diseases (GTDs) and to identify genes whose expression is specifically associated to these placental proliferative disorders we performed differential display techniques. Initially 19 candidate gene fragments were identified and differential expression was confirmed in eight of these fragments by Northern blot analysis. At the mRNA level ribosomal L26 (rL26), ribosomal L27 (rL27), a new Krüppel type zinc finger protein and TIS11d were preferentially expressed in normal early placenta (NEP) relative to complete hydatidiform mole (CHM), persistent gestational trophoblastic disease (PGTD) and choriocarcinoma JEG-3 cell line. In contrast, heterogeneous ribonucleoprotein A1 (hnRNPA1), the ferritin light chain mRNA, and the uncharacterized protein KIAA0992 were predominantly expressed in JEG-3 cell line. Finally, decorin, a prototype member of an expanding family of small leucine-rich proteoglycans, showed high expression in CHM. In addition we demonstrated by immunohistochemistry analysis that increased decorin mRNA in CHM reflected a genuine augmentation in average steady state mRNA levels within cells. Taken together, these findings provide several interesting candidates for regulation of tumorigenic expression as well as early placentation development, including those involved in protein synthesis (rL26 and rL27), metabolism (ferritin light chain), intercellular communication (decorin) and regulation of gene expression (Krüppel-like zinc finger, TIS11d and hnRNPA1). Information about such alterations in gene expression could be useful for elucidating the genetic events associated to gestational trophoblastic pathogenesis, developing new diagnostic markers, or determining novel therapeutic targets.

Profiling of retinoid mediated gene expression in synchronized human SCC cells using Atlas human cDNA expression arrays

While retinoids have been demonstrated to inhibit growth of many tumor cells, including SCC cells, the molecular mechanism by which retinoids suppress growth has not been elucidated. We previously found that the growth of SCC cells was significantly inhibited by all-trans-retinoic acid (all-trans-RA) treatment, and this inhibition was dependent on the binding and activation of RARs. These nuclear receptors bind retinoids and alter the rate of transcription of specific genes. To identify targets of the activated RARs which mediate growth inhibition, we growth arrested SCC-25 cells in G-0 and examined the effect of all-trans-RA on synchronized SCC-25 cells. All-trans-RA inhibited G-1 progression in quiescent SCC-25 cells stimulated by FBS. More specifically, we found that the all-trans-RA execution point maps to mid/late G-1, 6 to 10 h after stimulation. Using this synchronized cell system, we examined the expression of cell cycle regulatory genes in quiescent SCC-25 cells stimulated with FBS and treated with all-trans-RA. We found few changes in expression of these genes which could account for all-trans-RA inhibition of SCC-25 cell growth. In order to compare the patterns of expression of a wider selection of genes in all-trans-RA treated and non-treated SCC-25 cells, we have used expression array technology. We successfully performed expression profiling experiments on the Atlas Human cDNA arrays which contain 1176 human genes. We have identified several up-regulated and several down-regulated gene expression changes mediated by all-trans-RA treatment in synchronized SCC-25 cells. This novel information will be useful in defining the mechanism by which retinoids suppress the growth of SCC cells.

Optimisation of methods for selecting candidate genes from cDNA array screens: application to rat brain punches and pineal

DNA arrays are potentially powerful experimental tools within neuroscience but application of this technology to in vivo paradigms may, in practice, be limited by the sensitivity of transcript detection and inter-screen variation. Here we describe the use of brain punch micro-sampling, used in combination with commercially available cDNA arrays, for profiling brain gene expression in a mutant strain of rat (GAERS model of absence epilepsy). Furthermore, we describe a multi-step optimisation of analysis methods which provides for improved sensitivity and absence of bias in the selection of candidate genes which may be differentially expressed in the mutant. Our method has been validated through application to a second paradigm, rhythmic gene expression in the rat pineal gland. Our experimental design, and analysis method should therefore be generally applicable to subtle discriminations of transcript abundance within discrete brain areas.

Gestational trophoblastic diseases: new standards for therapy

Gestational trophoblastic disease (GTD) is a spectrum of rare neoplastic conditions that are highly curable, even in the presence of widely metastatic disease. These diseases vary from partial hydatidiform mole, which rarely metastasizes and infrequently requires treatment with chemotherapy, to choriocarcinoma, for which multi-agent chemotherapy is the standard treatment. Much has been learned regarding the epidemiology of this disease, and our understanding of the genetics underlying GTD is rapidly expanding. As technology such as ultrasonography and sensitive tests for beta-human chorionic gonadotropin have evolved, the presentation of molar pregnancy has significantly changed, although the incidence of persistent GTD has not decreased. This review highlights these recent advancements in the epidemiology, genetics, diagnosis, and treatment of gestational trophoblastic disease.