Search

Oct4 is a transcription factor that plays a crucial role in maintaining pluripotency of embryonic stem cells. Down-regulation of Oct4 is associated with the differentiation of trophectoderm cell lineage, from which the normal placenta derives. We investigated the methylation and expression status of Oct4 in normal placenta and gestational trophoblastic disease (GTD) as attempts to investigate the role of Oct4 in the pathogenesis of GTD. By methylation-specific PCR, we observed both methylated and unmethylated Oct4 alleles in all 25 first trimester and 10 term placentas while 33% (18/54) of hydatidiform moles, and two choriocarcinoma cell line (JEG3 and JAR), only displayed methylated Oct4 allele. By quantitative TaqMan real-time PCR, Oct4 mRNA was significantly reduced in hydatidiform moles (P=0.04), JEG3 and JAR (P=0.024) when compared with normal placentas. Oct4 methylation was significantly correlated with Oct4 mRNA expression in placenta and GTD (P=0.012). Hypermethylation in minimal promoter and exon 1 region of Oct4 were confirmed in JEG3 and JAR by bisulfite genomic sequencing. The Oct4 mRNA expression in JEG3 and JAR increased after treatment with 5-aza-2'-deoxycytidine and/or trichostatin A. Our findings suggest that Oct4 is down-regulated by hypermethylation in normal placenta and GTD and such process is important in pathogenesis of GTD.

Aims: To assess the proliferative activity of gestational trophoblastic disease (GTD) using one of the novel proliferation markers (MCM7) and to determine its prognostic value in hydatidiform mole (HM)., Methods and Results: Immunohistochemical staining for MCM7 was performed on 122 samples of paraffin-embedded trophoblastic tissues including 22 normal first-trimester placentas, 12 term placentas, 12 spontaneous miscarriages (SM), 21 partial moles (PM), 44 complete hydatidiform moles (CM), and 11 choriocarcinomas (CCA). The correlations between the proliferative indices assessed by MCM7, proliferating cell nuclear antigen (PCNA) and Ki67 (MIB1) immunoreactivity as well as clinical progress were assessed. MCM7 immunoreactivity was found predominantly in the nuclei of cytotrophoblast and intermediate trophoblast and decreased with placental maturation. MCM7 expression was highest in CCA, followed by CM, PM, normal first-trimester placenta, SM and term placenta. MCM7 index was significantly higher in PM and CM than in SM (P = 0.007, P < 0.001) but not between PM and CM themselves (P = 0.560). Eighteen of the 65 patients with HM developed persistent trophoblastic disease (PTD) requiring chemotherapy. There was no significant difference in MCM7 indices between the patients who developed PTD and those who did not (P = 0.312). MCM7 indices correlated well with Ki67 (P = 0.002) but not with PCNA (P = 0.054) indices. MCM7 indices demonstrated less variability than PCNA and Ki67 and may be a better proliferation marker than the latter two., Conclusions: We conclude that MCM7 is useful in differentiating molar and non-molar gestations but is not helpful in discriminating PM from CM or in predicting PTD.

The clinical significance of cadherins in gestational trophoblastic diseases (GTD) is not fully understood. In this study, the expression of E-cadherin and cadherin-11 in 12 normal placentas, 32 cases of hydatidiform mole (HM) including 15 complete HMs and 17 partial HMs, and five choriocarcinomas was investigated by immunohistochemistry and correlated with follow-up of HMs. Cases with available frozen blocks were further analyzed by western blot and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR). Methylation of E-cadherin was investigated by methylation-specific PCR in six normal first trimester placentas, 19 HMs and their associated deciduas. E-cadherin expression was localized to cytotrophoblast and intermediate trophoblast whereas cadherin-11 was expressed in syncytiotrophoblast, intermediate trophoblast, and decidua. Immunoreactivity of E-cadherin was reduced in choriocarcinoma and complete HM when compared with that in normal first trimester placenta (P < 0.01, P = 0.04). Hypermethylation of E-cadherin was demonstrated in three complete HMs with the lowest level of E-cadherin. Compared with normal first trimester placenta, immunoreactivity of cadherin-11 was higher in complete HM (P = 0.02), but lower in choriocarcinoma (P = 0.02). Such differential expression was confirmed by western blot and semiquantitative RT-PCR. No obvious association was observed between the development of persistent trophoblastic disease with the expression of E-cadherin and cadherin-11.

Aims: To assess the expression profile of the activated form of signal transducer and activator of transcription (Stat)3 in gestational trophoblastic disease (GTD) and correlate the findings with clinicopathological parameters. Methods and results: By immunohistochemistry, both cytoplasmic and nuclear expression of p-Stat3-Ser727 was demonstrated in 88 trophoblastic tissues, including placentas and GTD. Nuclear immunoreactivity of p-Stat3-Ser727 was significantly higher in hydatidiform mole (HM) ( P < 0.001) and choriocarcinoma ( P = 0.009) when compared with normal placentas. Placental site trophoblastic tumours (PSTT) and epithelioid trophoblastic tumours (ETT) also demonstrated higher nuclear p-Stat3-Ser727 expression than their normal trophoblast counterparts. Higher p-Stat3-Ser727 expression was confirmed in choriocarcinoma cell lines, JEG-3 and JAR, than in a normal trophoblast cell line, with both nuclear and cytoplasmic fractions demonstrated by immunoblotting. Spontaneously regressed HM showed significantly increased nuclear and cytoplasmic p-Stat3-Ser727 immunoreactivity over those that developed gestational trophoblastic neoplasia (GTN) ( P = 0.013, P = 0.039). There was a significant positive and inverse correlation between nuclear p-Stat3-Ser727 immunoreactivity and apoptotic indices [terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labelling and M30 CytoDeath antibody] ( P = 0.001, P < 0.001, Spearman’s ρ test) and Bcl-2 expression ( P = 0.034), respectively. Conclusions: p-Stat3-Ser727 plays a role in the pathogenesis of GTD, probably through the regulation of apoptosis. p-Stat3-Ser727 immunoreactivity is a potential marker in predicting GTN in HM. [ABSTRACT FROM AUTHOR]

Aims: To assess the expression of Id proteins in trophoblastic tissues and to correlate this with clinical parameters, proliferative and apoptotic indices as well as to related oncogene expression. Methods and results: Immunohistochemistry for Id1, Id2, Id3 and Id4 was performed on 83 trophoblastic tissues including 17 normal first-trimester placentas, seven term placentas, 47 hydatidiform moles (HM), and 12 spontaneous miscarriages. The four Id proteins were predominantly expressed in the villous and implantation site intermediate trophoblast. Expression of Id1 in HM was significantly higher than that in normal placenta (P = 0.0006) and spontaneous miscarriage (P = 0.0001) but did not correlate with subsequent development of gestational trophoblastic neoplasia (GTN). Id1 expression correlated with the proliferation index as assessed by MCM7 (P = 0.003) and Ki67 (P = 0.017) and with the apoptotic activity assessed by TUNEL (P = 0.001) and M30 CytoDeath antibody (P = 0.013). Moreover, the expression of Idi correlated with the expression of p53 (P = 0.004), p21WAF1/CIP1 (P = 0.003) but not with p16 (P = 0.107). Conclusions: Id proteins may play a role in the regulation of proliferative and apoptotic activity in trophoblastic tissue and are potentially useful in differentiating molar and non-molar gestation, but are not helpful in predicting GTN. [ABSTRACT FROM AUTHOR]