Implications in the maintenance of pregnancy: I. Presence of immunoreactive glycodelin in human umbilical cord vein endothelial cells

The Roles of Glycodelin in Cancer Development and Progression

Glycodelin is a kind of glycoprotein expressed in secretory endometrium, pregnancy deciduas, and amniotic fluid originally, which is vital for the maintenance of normal human reproductive activities. Recent researches have reported that glycodelin is specifically expressed in various malignancies, including female-specific cancers such as endometrial cancer, ovarian cancer and breast cancer, and non-gender specific cancers including lung cancer, and colon cancer, and glycodelin expression correlates with the diagnosis and prognosis of cancer patients. This review focuses on the expression of glycodelin in different cancers and its role in cancer development and progression. Glycodelin possesses the abilities to regulate cancer cell proliferation, differentiation, and invasion, promote cancer angiogenesis, and modulate the differentiation and function of immune cells including T cells, dendritic cells, monocyte-macrophages, natural killer cells and B cells participating in cancer development. The expression of glycodelin can be regulated by stromal cells, lysophosphatidic acid, histone deacetylase inhibitors, and relaxin. In summary, glycodelin is a promising biomarker for the diagnosis and prognosis of cancer patients, and depending on its distinct immunoregulatory effects, glycodelin can be a prospective target for cancer immunotherapy.

Expression of glycodelin and cyclooxygenase-2 in human endometrial tissue following three-dimensional culture

PROBLEM

Our previous study showed that in vitro culture of human endometrial tissue in a three-dimensional (3D) fibrin matrix could mimic the early stages of endometriosis with invasion, gland and stroma formation and sprouting of new vessels. The objective of the present study was to evaluate the expression of glycodelin (Gd) and cyclooxygenase-2 (COX-2), two angiogenic factors, to further validate the 3D culture model of endometriosis.

METHOD OF STUDY

Human endometrial fragments were obtained from endometrial biopsies and placed in a 3D fibrin matrix culture. Immunohistochemistry with specific antibodies to Gd and COX-2 was used to examine endometrial epithelium and blood vessels, and 4, 6-diamidino-2-phenylindole staining was used for nuclear identification.

RESULTS

Three-dimensional culture of human endometrial tissue in the fibrin matrix resulted in the proliferation of endometrial stromal cells, glandular epithelium and angiogenesis. Gd positive glandular epithelium was seen in 85% of wells with developing endometrial glands and COX-2 positive new vessels were seen in 80% of wells with angiogenesis-like structures after 4 weeks of culture.

CONCLUSION

Our findings confirm that angiogenesis occurs following the culture of endometrial tissue in the 3D fibrin matrix, and suggests that Gd and COX-2 might play important roles in promoting neovascularization and cell proliferation in the establishment of endometriosis.

Cord serum glycodelin concentrations in normal pregnancies and pregnancies complicated by diabetes

OBJECTIVE

Glycodelin is a glycoprotein released by secretory/decidualized endometrial glands. Its synthesis increases during pregnancy. Hormonal factors whose levels have been shown to change in diabetes (vascular endothelial growth factor, relaxin) may mediate the actions or regulate the synthesis of glycodelin. Cord serum glycodelin levels have not been studied in pregnancies complicated by diabetes.

METHODS

Cord serum glycodelin concentrations were measured at birth by an immunofluorometric assay in 62 normal pregnancies, in 67 pregnancies complicated by type 1 diabetes, and in 28 pregnancies complicated by insulin-treated gestational diabetes.

RESULTS

The mean glycodelin concentration in cord serum was 2.7 ng/ml (standard error of the mean 0.6) in normal pregnancies. The concentration was not altered in pregnancies complicated by diabetes. Cord serum glycodelin concentrations were also unaltered in diabetic pregnancies with hypertensive disorders (chronic hypertension, pregnancy-induced hypertension or pre-eclampsia) or fetal macrosomia. There was a negative borderline correlation between cord serum glycodelin concentrations and the birth weight in pregnancies complicated by diabetes (r=-0.21, p=0.049).

CONCLUSIONS

Decidual function, as assessed by cord serum glycodelin levels, is not markedly altered in diabetic pregnancies. The negative correlation between cord serum glycodelin and the birth weight of the newborns in diabetic pregnancies may be due to the decline in glycodelin levels with advancing pregnancy in the third trimester.

Lysophosphatidic acid induces glycodelin gene expression in cancer cells

Glycodelin is a glycoprotein that has been suggested to be important in normal pregnancy and in malignancy. The regulation of its synthesis has not been studied. In this study, we report the induction of glycodelin gene expression by lysophosphatidic acid (LPA). We studied the effect of LPA (5, 10 and 25 microM) on glycodelin production in breast (MDA-MB-231), cervical (Hela), endometrial (RL-95), ovarian cancer (OVCAR-3) and erythroleukemia (K562) cells. There was a dose-dependent (5-25 microM) induction of glycodelin gene and protein expression in these cell types. LPA is a mimic of phorbol myristate acetate (PMA) action and is found to be elevated in high concentrations in the serum of cancer subjects. As glycodelin is an angiogenic protein with a potential immunosuppressive role, control of LPA synthesis might offer a potential target for intervention.

Angiogenic role for glycodelin in tumorigenesis

Angiogenesis plays an important role in neovascularization in tumors. Glycodelin, a hormone-responsive protein, has been detected in tumors of reproductive organs and is found in high levels in the plasma of subjects with gynecological malignancies. Glycodelin is also found in the endothelial cells of the umbilical cord and in the blood vessels of tumors. In this study, we tested whether glycodelin-rich amniotic fluid and a synthetic peptide derived from the sequence of glycodelin peptide (Gp) might promote angiogenic response by examining the migration and tube formation in human umbilical cord vein endothelial cells (HUVECs). Increased migration and tube formation of HUVECs were found in the presence of amniotic fluid and Gp, and this increase was blocked by antibody to Gp and by an anti-vascular endothelial growth factor (VEGF) antibody, suggesting that the angiogenic effects of glycodelin might be mediated by VEGF. The results also showed that Gp significantly increased the release of VEGF protein and mRNA expression in HUVECs, RL-95 (human endometrial carcinoma cells), OVCAR-3 (human ovarian adenocarcinoma cells), EM42 (human endometrial epithelial cells), THP-1 (human monocyte), and MCF-7 and MDA-MB-231 (human breast adenocarcinoma cells) cell lines. VEGF receptor Fit-1 mRNA expression in HUVECs was also increased in the presence of Gp. These findings, together with the suggestion from the literature that glycodelin may have immunosuppressive properties, suggest that glycodelin might play an important role in neovascularization during embryogenesis and tumor development.

Increased glycodelin levels in gynecological malignancies

Glycodelin, an immunosuppressive protein with contraceptive properties, is synthesized by a variety of tissues and cell types. The ability of reproductive tissues to synthesize glycodelin is of major interest in pregnancy and disease conditions. We studied glycodelin levels in subjects with malignant gynecological tumors and in control subjects. Using a polyclonal glycodelin antibody against the synthetic glycodelin peptide sequence, an enzyme-linked immunosorbent assay (ELISA) was devised to measure plasma glycodelin levels. The assay detected as much as 5 ng/ml of glycodelin. There was a significant increase in plasma glycodelin levels in endometrial > ovarian > cervical cancer subjects when compared to those of controls. Strong expression of mRNA and protein were found in the ovarian and endometrial tumor tissues. Given glycodelin's immunosuppressive abilities, increased level of glycodelin may facilitate tumor growth in gynecological malignancies.

Implications in the management of pregnancy: II. Low levels of gene expression but enhanced uptake and accumulation of umbilical cord glycodelin

OBJECTIVE

We recently reported the presence of glycodelin in the endothelial cells of human umbilical cord. The objective of the current study is to determine whether human umbilical cord endothelial cells synthesize glycodelin.

DESIGN

Controlled clinical study.

SETTING

Healthy women undergoing normal delivery at Grady Memorial Hospital, Atlanta, Georgia.

PATIENT(S)

Healthy women undergoing normal delivery.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Human umbilical cord was collected after full-term delivery and total RNA from endothelial cells was isolated. Reverse-transcription polymerase chain reaction (RT-PCR) was performed by using primers from glycodelin sequence. Human umbilical cord endothelial cells at passage 3 were incubated with glycodelin-derived peptide or glycodelin-rich amniotic fluid. Immunocytochemical analysis was performed by using purified chicken anti-glycodelin peptide antibody to detect the accumulation of glycodelin in cells.

RESULT(S)

Little or no glycodelin message was detectable in the endothelial cells from human umbilical cord vein by RT-PCR and Southern blot analysis. However, these cells readily took up glycodelin protein and glycodelin-derived synthetic peptide from the medium.

CONCLUSION(S)

The presence and accumulation of glycodelin in the umbilical cord might indicate their potential role in the survival of fetal tissue in the maternal environment.