Cytokine stimulation of the choriocarcinoma cell line JEG-3 leads to alterations in the HLA-G expression profile.

The checkpoint molecule human leukocyte antigen (HLA)-G has restricted tissue expression, and plays a role in the establishment of maternal tolerance to the semi-allogenic fetus during pregnancy by expression on the trophoblast cells in the placenta. HLA-G exists in at least seven well-described mRNA isoforms, of which four are membrane-bound and three soluble. Regulation of the tissue expression of HLA-G and its isoforms is relatively unknown. Therefore, it is important to understand the regulation of HLA-G, and the HLA-G+ choriocarcinoma cell line JEG-3 is a widely used cellular model. We hypothesized that cytokines present in the microenvironment can regulate the HLA-G expression profile. In the present study, we systematically stimulated JEG-3 cells with various concentrations of IL-2, IL-4 IL-6, IL-10, IL-12, IL-15, IL-17A, TGF-ß1, TNF-α and IFN-γ1b. The results suggest that IFN-γ plays a role in maintenance of HLA-G expression, while IL-10 might be involved in regulation of the isoform profile.

The role of endoplasmic reticulum aminopeptidase 2 in modulating immune detection of choriocarcinoma.

Gestational choriocarcinomas are derived from placental trophoblast cells, with HLA-C being the only class I polymorphic molecule expressed. However, choriocarcinomas have not been profiled for endoplasmic reticulum aminopeptidase 2 (ERAP2) expression. ERAP2 trims peptides presented by human leukocyte antigens (HLA) that have shown to modulate immune response. Over 50% of choriocarcinomas we screened lack ERAP2 expression, which suggests that the absence of ERAP2 expression allows immune evasion of choriocarcinoma cells. We demonstrate that the ability of choriocarcinoma cells to activate lymphocytes was lowest with cells lacking ERAP2 (JEG-3) or HLA-C (JAr). This observation suggests that activation is dependent on expression of both ERAP2 and HLA-C molecules. In addition, an ERAP2 variant in which lysine is changed to asparagine (K392N) results in increased trimming activity (165-fold) for hydrophobic peptides and biologically never been detected. We hypothesize that homozygosity for the N392 ERAP2 variant is prohibited because it modulates the immune recognition of placental trophoblasts. We demonstrate that NK-cell activation and killing were significantly dependent on forced expression of the N392 ERAP2 isoform in JEG-3 cells. Cytotoxicity was confirmed by 7AAD killing assays showing that N392 ERAP2-isoform expressing JEG-3 cells had the highest percentage of apoptotic cells independent of the expression level of CD11a on lymphocytes. This is the first report showing that N392 ERAP2 promotes an immune clearance pathway for choriocarcinoma cells, and provides an explanation for why embryonic homozygosity for the N392 ERAP2 variant is not detected in any population.

The choriocarcinoma cell line JEG-3 upregulates regulatory T cell phenotypes and modulates pro-inflammatory cytokines through HLA-G.

An understanding of the interactions between immune cells and trophoblast cells, as well as choriocarcinoma cells, are of extreme importance in reproductive immunology and cancer immunology. In this study, we found that the human HLA-G-positive choriocarcinoma cell line JEG-3 upregulates CD4+CD25hiCD127lo T cells, increases the expression of HLA-G+CD4+ and CD8+ T cells, and decreases the expression of ILT2+ on CD4+ T cells in resting PBMCs after six days of co-culture. Expression of HLA-G on JEG-3 cells did not affect regulatory T cell phenotypes, but promoted modulation of pro-inflammatory cytokines IFN-γ, TNF-α and IL-17A. When JEG-3 cells were stimulated with rhIFN-γ prior to co-culture, CD4+HLA-G+ T cells were significantly increased, and IFN-γ and TNF-α elevated. Taken together, the results indicate that JEG-3 cells upregulate regulatory T cell phenotypes and modulate the level of pro-inflammatory cytokines, which might be important mechanisms in the tumor microenvironment and at the feto-maternal interface during pregnancy.

Durable remission for a woman with refractory choriocarcinoma treated with anti-endoglin monoclonal antibody and bevacizumab: A case from the New England Trophoblastic Disease Center, Brigham and Women's Hospital and Dana-Farber Cancer Institute.

A 36-year-old with metastatic and refractory choriocarcinoma following single- and multi-agent chemotherapy and surgical metastectomy experienced a durable remission after receiving therapy with an anti-endoglin monoclonal antibody and bevacizumab. Treatment options and scientific advances in this disease are highlighted.

Effects of Anti-ß2-Glycoprotein I Antibody on the Expression of Toll-like Receptors mRNA in Choriocarcinoma and Primary Trophoblast Cells.

OBJECTIVE: To investigate the effects of the anti- ß2-glycoprotein I (anti-ß2-GPI) antibody on the tro- phoblast by evaluating the effects of the anti-ß2-GPI antibody on the expression of toll-like receptor (TLR) mRNA in choriocarcinoma cells and primary trophoblast cells. STUDY DESIGN: We cul- tured the choriocarcinoma cells (BeWo) and the pri- mary first trimester tropho- blast with the IgGs taken from anti-ß2-GPI antibody-positive and -negative sera. Four hours later we purified the RNAs from those cells. We measured the expressions of TLR mRNA in cells using real-time. PCR. RESULTS: The expression of TLR mRNA increased in BeWo cells and primary trophoblast cells cultured with the IgGs taken from anti-ß2-GPI antibody-positive women. Specifically, the expression of TLR1, 2, and 4 in BeWo cells -and TLRI, 3, 4, and 9 in first trimester trophoblast cells increased significantly. CONCLUSION: The anti-ß2-GPI antibody-positive IgG increased the TElR mRNA expression in choriocarcino- ma cells and primary trophoblast cells. We suggest that anti-ß2-GPI antibodies may bind to trophoblast and increase the expression of TLR mRNA.

Effects of polyvalent immunoglobulins in patients with recurrent pregnancy loss and antibodies to the choriocarcinoma cell line JEG-3.

OBJECTIVE: The benefit of polyvalent immunoglobulins (IVIG) for patients with recurrent pregnancy loss (RPL) is controversially discussed. Anti-trophoblast antibodies as an expression of immune pathology have been associated with RPL. We investigated whether the antibody activity against the choriocarcinoma cell line JEG-3 in RPL patients is influenced in vitro by IVIG. STUDY DESIGN: Sera of 110 unexplained RPL patients with positive anti-JEG-3 antibodies were coincubated with IVIG in different concentrations (10mg/ml, 20mg/ml, 40mg/ml). Coincubation with human albumin in identical concentrations served as control. Anti-JEG-3 reactivity was measured by using flow cytometry in comparisons with two in-house standards antibody probes of low and high reactivity as described before. Anti-JEG-3 reactivity above the 95% confidence interval of controls was defined as positive. RESULTS: Incubating RPL sera with 10mg/ml IVIG significantly decreased anti-JEG-3 activity (p<0.001). Increasing IVIG concentration to 40mg/ml resulted in a slightly additionally reduction (p=0.42). In contrast, coincubation with albumin in identically concentrations did not affect anti-JEG-3 activity (p>0.40). CONCLUSION: Coincubation with IVIG in vitro leads to a significant suppression of anti-JEG-3 activity in the sera of RPL patients.

Human endogenous retrovirus envelope proteins target dendritic cells to suppress T-cell activation.

Though mostly defective, human endogenous retroviruses (HERV) can retain open reading frames, which are especially expressed in the placenta. There, the envelope (env) proteins of HERV-W (Syncytin-1), HERV-FRD (Syncytin-2), and HERV-K (HML-2) were implicated in tolerance against the semi-allogenic fetus. Here, we show that the known HERV env-binding receptors ASCT-1 and -2 and MFSD2 are expressed by DCs and T-cells. When used as effectors in coculture systems, CHO cells transfected to express Syncytin-1, -2, or HML-2 did not affect T-cell expansion or overall LPS-driven phenotypic DC maturation, however, promoted release of IL-12 and TNF-α rather than IL-10. In contrast, HERV env expressing choriocarcinoma cell lines suppressed T-cell proliferation and LPS-induced TNF-α and IL-12 release, however, promoted IL-10 accumulation, indicating that these effects might not rely on HERV env interactions. However, DCs conditioned by choriocarcinoma, but also transgenic CHO cells failed to promote allogenic T-cell expansion. This was associated with a loss of DC/T-cell conjugate frequencies, impaired Ca(2+) mobilization, and aberrant patterning of f-actin and tyrosine phosphorylated proteins in T-cells. Altogether, these findings suggest that HERV env proteins target T-cell activation indirectly by modulating the stimulatory activity of DCs.

Maternofetal transplacental transport of recombinant IgG antibodies lacking effector functions.

The neonatal Fc receptor (FcRn) directs the transfer of maternal immunoglobulin G (IgG) antibodies across the placenta and thus provides the fetus and newborn with passive protective humoral immunity. Pathogenic maternal IgG antibodies will also be delivered via the placenta and can cause alloimmunity, which may be lethal. A novel strategy to control pathogenic antibodies would be administration of a nondestructive IgG antibody blocking antigen binding while retaining binding to FcRn. We report on 2 human IgG3 antibodies with a hinge deletion and a C131S point mutation (IgG3ΔHinge) that eliminate complement activation and binding to all classical Fcγ receptors (FcγRs) and to C1q while binding to FcRn is retained. Additionally, 1 of the antibodies has a single point mutation in the Fc (R435H) at the binding site for FcRn (IgG3ΔHinge:R435H). We compared transplacental transport with wild-type IgG1 and IgG3, and found transport across trophoblast-derived BeWo cells and ex vivo placenta perfusions with hierarchies as follows: IgG3ΔHinge:R435H>wild-type IgG1≥IgG3ΔHinge and IgG3ΔHinge:R435H=wild-type IgG1=wild-type IgG3>>>IgG3ΔHinge, respectively. Collectively, IgG3ΔHinge:R435H was transported efficiently from the maternal to the fetal placental compartment. Thus, IgG3ΔHinge:R435H may be a good candidate for transplacental delivery of a nondestructive antibody to the fetus to combat pathogenic antibodies.

The human leukocyte antigen G promotes trophoblast fusion and ß-hCG production through the Erk1/2 pathway in human choriocarcinoma cell lines.

The human leukocyte antigen G (HLA-G) is expressed on the fetal-maternal interface and plays a role in protecting fetal-derived trophoblasts from the maternal immune response, allowing trophoblasts to invade the uterus. However, HLA-G also possesses immune suppressing-independent functions. We found that HLA-G expressing BeWo choriocarcinoma cells increased cell-cell fusion compared to control BeWo cells under forskolin treatment. Regardless of forskolin treatment, the expression of fusogenic gene mRNAs, including syncytin-1, the transcription factor glial cell missing 1 (Gcm1), and beta human chorionic gonadotropin (ß-hCG) were elevated. HLA-G up-regulates ß-hCG production in human choriocarcinoma cells because HLA-G knockdown in JEG-3 cells induces a dramatic decrease in ß-hCG compared with control cells. The defect in ß-hCG production in HLA-G knocked-down cells could not be completely overcome by stimulating hCG production through increasing intracellular cAMP levels. HLA-G expressing cells have increased phosphorylation levels for extracellular signal-regulated kinase1/2 (Erk1/2) in BeWo cells. The Erk1/2 pathway is inactivated after the inhibition of HLA-G expression in JEG-3 cells. Finally, Erk1/2 inhibition was able to suppress the increased hCG production induced by HLA-G expression. Together, these data suggest novel roles for HLA-G in regulating ß-hCG production via the modulation of the Erk1/2 pathway and by inducing trophoblast cell fusion.

Trophoblast cells are able to regulate monocyte activity to control Toxoplasma gondii infection.

INTRODUCTION: Toxoplasma gondii is an intracellular parasite that causes severe disease when the infection occurs during pregnancy. Trophoblast cells constitute an important maternal-fetal barrier, with monocytes concentrating around them. Thus, interactions between trophoblasts and monocytes are important for maintaining a successful pregnancy, especially in cases of infection. This study aimed to evaluate the role of trophoblast cells (BeWo line) on monocyte (THP-1 line) activity in the presence or absence of T. gondii infection. METHODS: THP-1 cells were stimulated with supernatants of BeWo cells, previously infected or not with T. gondii, and then infected with parasites. The supernatant of both cells were collected and analyzed for cytokine production and T. gondii proliferation in THP-1 cells was determined. RESULTS: The results showed that after infection, the pattern of cytokines secreted by THP-1 and BeWo cells was characterized as a pro-inflammatory profile. Furthermore, supernatant of BeWo cells infected or not, was able to change the cytokine profile secreted by infected THP-1 cells, and this supernatant became THP-1 cells more able to control T. gondii proliferation than those that had not been stimulated. DISCUSSION: This effect was associated with secretion of interleukin (IL)-6 by the THP-1 cells and soluble factors secreted by BeWo cells, such as IL-6 and MIF. CONCLUSION: Together, these results suggest that trophoblast cells are able to modulate monocyte activity, resulting in the control of T. gondii infection and subsequent maintenance of pregnancy.

Anti-GalNAcß: a novel anti-glycan autoantibody associated with pregnancy loss in women with antiphospholipid syndrome and in a mouse experimental model.

OBJECTIVES: We evaluated the presence of anti-glycan antibodies (aGA) in patients with antiphospholipid syndrome (APS), and associations between aGA and clinical features of the disease. METHODS: Sera from APS patients and healthy controls were analyzed for aGA levels by ELISA. Analysis of the association of specific aGA with clinical manifestations of APS was performed. Selected aGA were affinity-purified and injected intravenously into naive mice which were tested for fetal loss. Matrigel invasion assay was performed for detection of choriocarcinoma cells (JAR) invasion and proliferation in the presence of selected aGA. Culture fluid of JAR invasion assays was analyzed for the presence of MMP2 and MMP9. RESULTS: High levels of several aGA were found in APS sera, of which anti-GalNAc-ß was significantly associated with recurrent pregnancy loss. Naive mice infused intravenously with anti-GalNAc-ß developed increased fetal loss. Anti-GalNAc-ß significantly inhibited the in-vitro percentage of JAR invasiveness and the secretion of MMP2 and MMP9 by human JAR cells. CONCLUSIONS: APS sera contain significant levels of aGA directed against several glycans. Anti-GalNAc-ß Ab is specifically associated with recurrent pregnancy loss both in human patients and experimental mouse model. The pathogenic effects of anti-GalNAc-ß include inhibition of JAR cells invasiveness accompanied by decreased MMP2 and MMP9 secretion.

Crucial cross-talk of interleukin-1ß and progesterone in human choriocarcinoma.

Choriocarcinoma is a highly malignant epithelial tumour that is most often associated with hydatidiform mole and presents the most common emergency medical problem in the management of trophoblast disease. We hypothesise that the hormones/cytokines present within the tumour microenvironment play key roles in the development of choriocarcinoma. In this study we assessed the effects of interleukin-1ß (IL-1ß) on cell death in the presence or absence of the sex hormone progesterone using two choriocarcinoma cell lines (BeWo and JEG-3) as in vitro experimental models. Although IL-1ß induced cell death in both cell lines, the effect was more pronounced in JEG-3 cells, where cell death reached 40% compared to 15% in BeWo cells. Cell death of JEG-3 cells in response to IL-1ß was significantly decreased by co-treatment with 100 nM and 1000 nM progesterone and completely abolished at a progesterone concentration of 1000 nM. Progesterone was also able to induce phosphorylation of ERK1/2 in these cells. Pretreatment of JEG-3 cells with a specific MAPK inhibitor (UO126) inhibited progesterone's inhibitory effect on cell death. Collectively, these data provide evidence of cross-talk between progesterone and IL-1ß in this aggressive and poorly understood tumour that involves activation of a MAPK pathway and involvement of numerous progesterone receptors.

A possible coagulation-independent mechanism for pregnancy loss involving ß(2) glycoprotein 1-dependent antiphospholipid antibodies and CD1d.

PROBLEM ß(2) glycoprotein1 (ß(2) GP1)-dependent antiphospholipid antibodies (aPL) increase the risk for recurrent pregnancy loss. We address whether anti-ß(2) GP1 antibodies can interact with phosphatidylserine (PS)-bearing CD1d on trophoblast cells and induce local inflammation. METHODS CD1d-bearing choriocarcinoma cells were used in flow cytometry and immunoprecipitation experiments. CD1d-mediated cytokine induction was assessed using antibody cross-linking. Cytokine production during co-culture of decidual lymphocytes with CD1d-bearing cells was also examined. RESULTS Trophoblast surface-expressed CD1d forms a complex with PS-bound ß(2) GP1. Anti-ß(2) GP1 mAb cross-linking causes IL12p70 release from CD1d-bearing cells. IL12p70 release from CD1d-bearing trophoblast cells was also induced during co-culture with human decidual lymphocytes. The addition of anti-ß2GP1 mAb to co-cultures resulted in a three-fold increase in IL12p70 secretion. IFNγ secretion from decidual lymphocytes was also induced during co-culture with anti-ß2GP1 mAbs. CONCLUSIONS ß(2) GP1-dependent IL12 release from CD1d-bearing trophoblast in the presence of aPL may link the antiphospholipid syndrome to pregnancy loss via an inflammatory mechanism.

Antitrophoblast antibodies are associated with recurrent miscarriages.

OBJECTIVE: To investigate whether antitrophoblast antibodies are associated with unexplained recurrent miscarriages, we used choriocarcinoma cells JEG-3, since these cells are negative for class I and II antigens, but they do express HLA-G, resembling an antigen expression of endovascular and interstitial trophoblasts. DESIGN: Case-control study. SETTING: Academic research center. PATIENT(S): One hundred ninety-four patients with two or more consecutive, idiopathic recurrent miscarriages (RM; <20 weeks of gestation) were compared with 110 controls with normal pregnancies and without pregnancy complications. INTERVENTION(S): Anti-JEG-3 reactivities were measured by using flow cytometry and comparisons with two in-house standards antibody samples of low and high reactivity. MAIN OUTCOME MEASURE(S): Anti-JEG-3 reactivities above the 95% confidence interval of controls were defined as positive. RESULT(S): Sera of RM patients reacted significantly stronger with JEG-3 cells than that of controls. In addition, RM patients significantly more often had positive anti-JEG-3 reactivities (17.5%) than controls 5%. This difference was markedly increased with a subgroup of 80 RM patients who had three or more miscarriages, as 27 of these women (34%) were anti-JEG-3 positive. CONCLUSION(S): Antitrophoblast antibodies show significantly more mean channel shift reactivities, and positive reactivities are significantly more prevalent in RM patients as compared with controls. Such antibodies may be involved in mechanisms affecting pregnancies.

Interleukin-11 increases invasiveness of JEG-3 choriocarcinoma cells by modulating STAT3 expression.

Amongst the interleukin-6 (IL-6) family of cytokines, leukemia inhibitory factor (LIF) has been shown to promote trophoblast invasion and proliferation. In the present study interleukin-11 (IL-11), another member of the IL-6 family, was investigated for its role in regulating invasion, migration and proliferation of JEG-3 choriocarcinoma cells. JEG-3 cells, like extra villous trophoblast (EVT), express mRNA transcripts encoding IL-11 and IL-11 receptor-alpha (IL-11Ralpha). Treatment of JEG-3 cells with IL-11 led to an increase in invasion across Matrigel extracellular matrix without an increase in proliferation. There was a dose-dependent increase in activation of STAT3 under the influence of IL-11 with maximum Tyr705 phosphorylation by 10min. In addition, treatment of JEG-3 cells with IL-11 for 24h led to an increase in expression of unphosphorylated STAT1 and STAT3. Analysis of the nuclear fraction showed an increased localization of STAT3 following IL-11 treatment while STAT1 was absent. Silencing the expression of STAT3 by siRNA caused a 25% reduction in invasion compared to control cells, however this was not significant. Furthermore, treatment of STAT3-silenced JEG-3 cells with IL-11 led to a significant increase in invasion compared to STAT3-silenced cells without cytokine, but this was not significant compared to non-transfected control cells. Silencing the expression of gp130 but not of IL-6R abrogated the increase in invasiveness of JEG-3 cells following IL-11 treatment. In conclusion, activation and upregulation of STAT3 appears to be critical for the IL-11-mediated increase in invasiveness of JEG-3 cells.

Restoration of immune response gene induction in trophoblast tumor cells associated with cellular senescence.

Trophoblast cells and many cancer cells that harbor foreign antigens may evade immunity by epigenetic silencing of key immune response genes, including MHC class I and II and CD40. Chromatin active agents, such as histone deacetylase inhibitors (HDACi), induce immune response gene expression but often the expression levels are low and the cells lack a robust antigen presentation response. We show here that pre-treatment of trophoblast cells and certain cancer cells with agents that activate stress pathways (Ras oncogene, PMA or H2O2) and induce senescence can substantially enhance the induction of immune response genes (MHC class II, CD40, MICA, MICB) by HDACi and restore a vigorous IFN-gamma response in trophoblast cells and tumor cells. These results could potentially impact the development of novel anti-cancer therapeutic strategies.

Implantable diagnostic device for cancer monitoring.

Biopsies provide required information to diagnose cancer but, because of their invasiveness, they are difficult to use for managing cancer therapy. The ability to repeatedly sample the local environment for tumor biomarker, chemotherapeutic agent, and tumor metabolite concentrations could improve early detection of metastasis and personalized therapy. Here we describe an implantable diagnostic device that senses the local in vivo environment. This device, which could be left behind during biopsy, uses a semi-permeable membrane to contain nanoparticle magnetic relaxation switches. A cell line secreting a model cancer biomarker produced ectopic tumors in mice. The transverse relaxation time (T(2)) of devices in tumor-bearing mice was 20+/-10% lower than devices in control mice after 1 day by magnetic resonance imaging (p<0.01). Short term applications for this device are numerous, including verification of successful tumor resection. This may represent the first continuous monitoring device for soluble cancer biomarkers in vivo.

Human leucocyte antigen (HLA) expression of primary trophoblast cells and placental cell lines, determined using single antigen beads to characterize allotype specificities of anti-HLA antibodies.

Human trophoblast cells express an unusual repertoire of human leucocyte antigen (HLA) molecules which has been difficult to define. Close homology between and extreme polymorphism at the classical HLA class-I (HLA-I) loci has made it difficult to generate locus-specific monoclonal antibodies (mAbs). The problem of defining an antibody's reactivity against the thousands of existing HLA-I allotypes has often made it impossible to determine the HLA bound by a mAb in biological samples from a normal outbred population. Here we have used commercially available beads coated with individual HLA-I to characterize experimentally the reactivity of nine mAb against 96 common HLA-I allotypes. In conjunction with donor HLA-I genotyping, we could then define the specific HLA molecules bound by these antibodies in normal individuals. We used this approach to analyse the HLA expression of primary trophoblast cells from normal pregnancies; the choriocarcinoma cells JEG-3 and JAR; and the placental cell lines HTR-8/SVneo, Swan-71 and TEV-1. We confirm that primary villous trophoblast cells are HLA null whereas extravillous trophoblast cells express HLA-C, HLA-G and HLA-E, but not HLA-A, HLA-B or HLA-DR molecules in normal pregnancy. Tumour-derived JEG-3 and JAR cells reflect extravillous and villous trophoblast HLA phenotypes, respectively, but the HLA repertoire of the in vitro derived placental cell lines is not representative of either in vivo trophoblast phenotype. This study raises questions regarding the validity of using the placental cell lines that are currently available as model systems for immunological interactions between fetal trophoblast and maternal leucocytes bearing receptors for HLA molecules.

Interleukin-17 increased progesterone secretion by JEG-3 human choriocarcinoma cells.

PROBLEM: JEG-3 choriocarcinoma cell line has previously been reported to express a receptor for interleukin (IL)-17. The involvement of IL-17 in the production of progesterone and human chorionic gonadotropin by placental trophoblast has not been investigated. METHOD OF STUDY: The present study investigated the in vitro effect of IL-17 on progesterone and human chorionic gonadotropin (hCG) secretion by JEG-3 cells. Both hormones were quantified using enzyme-linked immunosorbent assays. RESULTS: The results showed that IL-17 significantly increased progesterone secretion at 6 (P < 0.001) and 24 (P < 0.01) hr, while this cytokine had no effect on hCG secretion. CONCLUSION: Interleukin-17 may regulate the function of JEG-3 cells through increased progesterone secretion.