Expression of epidermal growth factor receptor in gestational trophoblastic diseases

EGF stimulates human trophoblast cell invasion by downregulating ID3-mediated KISS1 expression

Background

During pregnancy, trophoblast cell invasion needs to be finely controlled. Aberrant trophoblast cell invasion is associated with placental diseases. Epidermal growth factor (EGF) and its receptor, EGFR, are expressed in trophoblast cells. Although the pro-invasive effect of EGF on trophoblast cells has been reported, the underlying mechanism remains largely unknown.

Results

In the present study, we conducted an RNA sequencing (RNA-seq) to HTR-8/SVneo human trophoblast cells in response to EGF and identified KISS1 as a target gene of EGF. The human KISS1 gene encodes kisspeptin, also known as metastin, which can suppress tumor metastasis. Our results showed that EGF treatment downregulated KISS1 expression and secretion by activating the EGFR-mediated PI3K/AKT signaling pathway. In addition, the expression of inhibitor of DNA-binding protein 3 (ID3) was downregulated by EGF and that was required for the EGF-suppressed KISS1 expression. Functionally, transwell invasion assays demonstrated that EGF stimulated human trophoblast cell invasion by downregulating KISS1 expression. Preeclampsia (PE) is a placental disease characterized by insufficient trophoblast cell invasion. Our clinical results revealed that serum levels of EGF were downregulated while serum and placental levels of KISS1 were upregulated in PE patients.

Conclusions

This study demonstrates that downregulation of EGF can lead to poor trophoblast cell invasion by increasing KISS1 expression which subsequently contributes to the pathogenesis of PE.

Immunolocalization and Quantitation of Transforming Growth Factor Alpha in Hydatidiform Mole

Complete hydatidiform mole (CHM), a condition related to abnormal gestation, occurs predominantly in the young reproductive age group and has a high prevalence rate in the Trivandrum region, occurring in 1.2% of deliveries. Transforming growth factor alpha (TGF-α) is an important growth regulatory molecule, the location and function of which at the human fetomaternal interface in CHM remains to be determined. The present study examined the presence of TGF-α in the normal and complete molar placenta and decidua throughout gestation. A total of 149 complete molar placental tissue samples and 96 normal placental tissue samples were evaluated for TGF-α expression by immunohistochemistry and 50 each of CHM and normal placental tissue for TGF-α concentration by radioimmunoassay. The peptide was localized immunocytochemically with a monoclonal anti-TGF-α antibody on paraffin-embedded tissue using the avidin-biotin complex peroxidase technique with aminoethyl carbazole as the chromogen. In molar placenta, villous trophoblast cells (syncytiotrophoblasts and cytotrophoblasts) showed intense cytoplasmic staining at all gestational ages compared to normal placenta of the same gestational age. The tissue concentration of TGF-α was highly overexpressed in the molar placenta (10-1000 fold) compared to that in the normal placenta. The results indicate that TGF-α is present in trophoblasts throughout human gestation and may provide additional growth advantage to maintenance of the hyperproliterative condition in trophoblastic tumors.

Insights into dovetailing GTD and Cancers

Gestational trophoblastic diseases (GTD) encompass a group of placental tumors which mostly arise due to certain fertilization defects, resulting in the over-proliferation of trophoblasts. The major characteristic of this diseased state is that β-hCG rises up manifold than that is observed during pregnancy. The incidence of GTD when analyzed on a global scale, figures out that there is a greater risk in South-East Asia, the reason of which remains unclear. An insight into any possible correlation of GTD incidence with cancers, other than choriocarcinoma, is being attempted here. Also, we review the recent developments in research on the molecular etiopathology of GTD. This review would render a wider eye towards a new paradigm of thoughts to connect GTD and breast cancer, which has not been into the picture till date.

The management of recurrent and drug-resistant gestational trophoblastic neoplasia (GTN)

Gestational trophoblastic neoplasia (GTN) comprises a spectrum of disease from low-risk disease which can be cured with simple relatively non-toxic treatment, to extremely aggressive tumours which require specialized management. The prognostic variables in patients with GTN are different from those in other gynaecological malignancies, and the major adverse prognostic variables include long interval from antecedent pregnancy, high concentrations of the pregnancy hormone, human chorionic gonadotrophin, metastases in brain and liver and failure of prior treatment. Patients who relapse after their prior treatment can also be categorized into different risk groups. Salvage treatment can vary from single agent actinomycin D to combination chemotherapy and, in selected cases, surgery. With appropriate management, the majority of patients can achieve long-term remission and, in most cases, preserve fertility. The late side-effects of more intensive treatment are a small risk of inducing second tumours and also of bringing forward the age of menopause.

Epidermal growth factor receptor is a marker for syncytiotrophoblastic cells in testicular germ cell tumors

The epidermal growth factor receptor (EGFR) has been implicated in the pathogenesis, therapy and prognosis of various tumor types. The aim of this study was to investigate EGFR expression in a large series of testicular germ cell tumors (TGCTs). A total of 88 TGCTs (37 of pure type and 51 of mixed type) comprising a total of 44 seminoma, 49 embryonal carcinoma, 32 yolk sac tumor, 28 teratoma and 7 choriocarcinoma components were immunostained for EGFR. EGFR reactivity was observed in the stromal cells of embryonal carcinoma (29%) and in epithelial compartments of teratoma (71%). In addition, EGFR staining was consistently detected in syncytiotrophoblastic cells of choriocarcinoma, seminoma, embryonal carcinoma and yolk sac tumor components. EGFR staining, similar to beta-human chorionic gonadotropin (HCG) immunohistochemistry, was efficiently able to identify syncytiotrophoblastic cells in TGCTs. This study shows that EGFR is expressed in a subset of testicular germ cell tumors and suggests that EGFR may be a useful marker for syncytiotrophoblastic cells.

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.

Altered mitochondrial gene expression in human gestational trophoblastic diseases

To assess the molecular basis of phenotypic alterations present in the gestational trophoblastic diseases (GTDs) and to identify genes whose expression is specifically associated with these placental proliferative disorders we performed differential display (DD) techniques. This strategy resulted in the isolation of four mitochondrial transcripts downregulated in benign, as well as in malignant, trophoblastic diseases encoding the cytochrome oxidase subunit I (COX I), the ATPase subunit 6, the 12S ribosomal RNA (12S rRNA) and the transfer RNA for phenylalanine (tRNA(Phe)). This expression pattern was confirmed by Northern blot in normal early placenta (NEP), complete hydatidiform mole (CHM), persistent gestational trophoblastic disease (PGTD) and the human choriocarcinoma derived cell line JEG-3. Quantification of mitochondrial DNA by dot blot indicated that these changes in expression were not associated with a significant alteration in the number of mitochondrial genome. In addition, a reduction in the mitochondrial transcription factor A (mtTFA) mRNA level was observed in benign as well as in malignant trophoblastic diseases in correlation with the decrease in the mitochondrial transcript levels. Furthermore, Western blot analysis for COX-I showed a close parallelism with the expression level of the cognate RNA. Taken together, these data demonstrate that a significant change in mitochondrial transcription is associated with the phenotypic alteration present in GTDs.

Expression of epidermal growth factor receptor-related family products in gestational trophoblastic diseases and normal placenta and its relationship with development of postmolar tumor

OBJECTIVE

The goal of this work was to study the expression of epidermal growth factor receptor (EGFR) and c-erbB-3 and c-erbB-4 oncogenes in gestational trophoblastic diseases and normal first-trimester placenta.

STUDY DESIGN

Paraffin sections of 16 cases of partial mole, 25 cases of complete mole, 10 cases of gestational choriocarcinoma, and 11 cases of therapeutic abortion were studied immunohistochemically for EGFR, c-erbB-3, and c-erbB-4 proteins. The presence of EGFR mRNA was studied using in situ hybridization.

RESULTS

Staining for EGFR was detected immunohistochemically in all cell types in gestational trophoblastic diseases and normal placenta. In situ hybridization for EGFR mRNA correlated with immunostaining for EGFR in all tissues studied. All 10 cases of choriocarcinoma exhibited strong immunoreactivity for EGFR. The levels of expression of EGFR in choriocarcinoma and syncytiotrophoblasts and cytotrophoblasts in complete mole were significantly greater than those in syncytiotrophoblasts and cytotrophoblasts in both normal placenta and partial mole (P < 0.01, P < 0.01). Expression of c-erbB-3 did not significantly differ among placental and gestational trophoblastic disease tissues and trophoblastic cell types except for significantly increased expression in choriocarcinoma as compared with cytotrophoblasts of partial mole (P = 0.02). The placenta, complete and partial mole, and choriocarcinoma tissues demonstrated similar immunoreactivity for c-erbB-4. Strong immunostaining for EGFR (P = 0.02) and c-erbB-3 (P < 0.01) in extravillous trophoblasts of complete mole was found to be significantly correlated with the development of persistent postmolar gestational trophoblastic tumor.

CONCLUSION

The EGFR-related family of oncogenes may be important in the pathogenesis of gestational trophoblastic diseases. The increased expression of EGFR and c-erbB-3 in complete mole may also influence the development of persistent gestational trophoblastic tumor.

A multivariate analysis of prognostic indicators in complete hydatidiform moles (CHM)

OBJECTIVE

To analyse prognostic factors in complete hydatidiform moles using multiple logistic regression analysis.

METHODS

Evaluation of host and tumour related parameters including (a) gestational age, patient age, parity, molar phenotype, grade of proliferation of the tumour and cytological atypia, (b) expression of beta-HCG, EGF, EGFR, TGF-alpha, TGF-beta, IL1-alpha, IL1-beta by immunohistochemistry, (c) serial monitoring of serum beta-HCG levels by ELISA, and (d) lectin binding using jack fruit lectin histochemistry as indices for persisting trophoblastic disease (PTD).

RESULTS

Serum beta-HCG levels at 4 weeks, cellular atypia, lectin binding, expression of TGF-alpha and IL1-beta showed highly significant correlation with persistence of the tumour (P<0.001). The sensitivity and specificity at 4 weeks in combination with cytological atypia to identify spontaneously regressing lesions was 100% and those requiring chemotherapeutic intervention was 80%.

CONCLUSION

The concentration of serum beta-HCG 4 weeks post evacuation(<300 mIU/ml) combined with cytological abnormalities could identify nearly 100% of the spontaneously regressing lesions (low risk) and 80% of those needing chemotherapeutic intervention (high risk), thereby suggesting that patients who have a serum beta-HCG at 4 weeks of evacuation <300 mIU/ml with no cytological atypia of the trophoblasts need only be followed up at long intervals, while those having a serum beta-HCG at 4 weeks of evacuation >300 mIU/ml accompanied with cytological atypia of the trophoblasts should be closely followed up.