Gestational Trophoblastic Disease (GTD) encompasses a spectrum of disease that involves abnormal trophoblastic proliferation. It includes hydatidiform mole (HM), placental site trophoblastic tumor (PSTT), epithelioid trophoblastic tumor (ETT) and choriocarcinoma (CCA). While HMs are abnormal pregnancies with limited invasive potential, CCAs are true malignancies requiring chemotherapy. Although the majority of HM is resolved by surgical intervention, approximately 8-30% of them would develop into persistent GTD. In addition to that, being the most aggressive neoplasm in GTD, choriocarcinoma is a frankly malignant gestational trophoblastic neoplasm (GTN) that could be arisen from HM and could be fetal when widespread metastasis is developed. However, the underlying mechanisms of this disease progression are still unclear. FBI-1 (Factor that Binds to Inducer of Short Transcripts (IST) protein 1) is a transcription factor that has been observed to be overexpressed in various types of human cancers. Recently, overexpression of FBI-1 is also reported in GTD and also in association with GTN development. However, the causes of FBI-1 overexpression in GTD are still unclear. This study aims to investigate gene amplification as a possible cause of FBI-1 overexpression in GTD. A quantitative real time PCR (qPCR) assay was established and was used to investigate ZBTB7A (the gene encoding FBI-1) amplification in GTD cell lines and clinical samples. Using our qPCR assay, we demonstrated that ZBTB7A is not amplified in the CCA cell lines JEG-3 and JAR, in comparison with an immortalized trophoblast cell line HTR-8/SVneo. Testing ZBTB7A amplification in clinical samples also obtained similar findings although overexpression of FBI-1 was demonstrated in our previous studies. This is the first report illustrating absence of ZBTB7A amplification in cells with FBI-1 overexpression. There are other techniques that can detect gene amplification and/or other genetic and epigenetic mechanisms that may govern FBI-1 expression in GTD. Further studies will be worthwhile to pursue as FBI-1 is a potential target for cancer therapy. / published_or_final_version / Pathology / Master / Master of Medical Sciences

Thesis (M.A.)--Trinity Evangelical Divinity School, 1994. / Abstract. Includes bibliographical references (leaves 42-49).

Thesis (MSc (Genetics))--University of Stellenbosch, 2006. / Pre-eclampsia is a multisystemic disorder with an incidence of ~6-8% in non-Caucasian women in the Western Cape. Trophoblast invasion is vital for adequate anchorage of the placenta to the uterine wall as well as for the optimisation of utero-placental blood flow in uncomplicated pregnancies. This process is facilitated by the fetal trophoblast cells that digest the extracellular matrix of the uterus by secreting various molecules, including the metalloproteinases (MMP), of which MMP-9 has an increased production during the first trimester. Leptin, an autocrine regulator of MMP-9 secretion, functions via the leptin receptor to prevent over-invasion of maternal tissues. The aim of this study was to investigate the role of the leptin (ob) and leptin receptor (obR) genes in predisposition to pre-eclampsia and involved screening the genes in South African non-Caucasian cohorts and performing statistical analysis to determine whether any variants contributed to the disease profile.

Thesis (MSc (Genetics))--University of Stellenbosch, 2009. / Pre-eclampsia is one of the most common hypertensive disorders of pregnancy in South Africa. Presently, the only cure for pre-eclampsia is delivery, which brings with it, additional complications. As an alternative, clinical management of this disorder relies on timely diagnosis. The predictive biomarker, Placental Protein 13 (PP13), is currently used for the early diagnosis of pre-eclampsia, in an ELISA-based diagnostic kit, developed by Diagnostic Technologies Limited (DTL)1. A decrease in serum PP13 levels has been reported during the first trimester of pregnancy in women who later develop pre-eclampsia. The function of PP13 has not been fully elucidated and it is also not known whether the reduction in PP13 levels is a cause or an effect of the disease. The use of PP13 as a predictive biomarker for pre-eclampsia therefore warrants a comprehensive study of this peptide and the encoding gene, LGALS13. The aim of this study was firstly to characterise LGALS13 using a range of in silico tools. PP13 was found to be most homologous to the predicted protein product of a neighbouring “putative” gene, LOC148003. A gene conversion event between these two genes most likely underlies the so-called “hotspot mutation” in LGALS13. Data also demonstrates that the DelT mutation disrupts functionally and structurally important features of the gene and peptide sequences. Through the analysis of the putative promoter region of LGALS13, the presence of a Stimulatory protein-1 (Sp1) binding sequence element was predicted, which has implications for regulation of LGALS13. Secondly, the study aimed to establish a study cohort for the investigation of the effect that the LGALS13 genotype has on the expression of its mRNA and protein products. Serum, plasma and whole blood samples were collected and prepared from 316 pregnant women. Placental tissue samples were obtained from a selected group of these subjects for RNA extraction. Once the sampling on the two remaining targeted deliveries has occurred, the collection of samples will be batched and sent to DTL in Israel, for PP13 measurement. DNA was extracted from the whole blood samples obtained, and all study participants were genotyped for seven sequence variants within the LGALS13 gene using (i) Multiphor Single Stranded Conformational Polymorphism and Heteroduplex (SSCP/HD) analysis, (ii) restriction enzyme analysis and (iii) DNA sequencing. The genotype data sets will be compared with PP13 levels when they become available, and also with clinical parameters, once the deliveries have all occurred and the database is complete. This study demonstrated the power of an in silico approach to direct the focus of future experimental work. The newly established study cohort will be used for prospective studies aiming at a better understanding of the role which LGALS13 and PP13 play in the early prediction of preeclampsia.

Diabetic pregnancy is associated with increased risk of congenital malformations. Previous studies have shown that maternal diabetes can interact with the vitamin A metabolite, all-trans retinoic acid (RA), in increasing embryonic susceptibility to caudal regression and neural tube defects. The aim of this thesis is to investigate the cellular and molecular mechanisms that underlie this interaction. / First hypothesis. RA concentration in the embryo is tightly regulated by the synthesizing enzyme retinaldehyde dehydrogenase type II (RALDH2), and the degrading enzyme CYP26. Alteration in expression levels of these enzymes under maternal diabetes may affect the availability of RA and thus its teratogenicity. / In conclusion, results of this thesis provide insight into the mechanism of how maternal diabetes interacts with RA in enhancing embryonic susceptibility to congenital malformations. This is also the first report to show that maternal diabetes alters RA homeostasis. (Abstract shortened by UMI.) / Second hypothesis. The transfer of RA to the nucleus for molecular action is regulated by cytoplasmic cellular retinoic acid binding proteins CRABP-I and CRABP-II. Alteration in expression levels of these binding proteins under maternal diabetes may affect the amount of RA reaching the nucleus and thus its teratogenicity. / Third hypothesis. The action of RA is mediated via different nuclear retinoic acid receptors (RAR) and retinoid X receptors (RXR). Alteration in expression levels of these receptors under maternal diabetes may affect the efficacy of RA signal transduction and thus its teratogenicity. / Three hypotheses are proposed to explain the underlying mechanism of increased embryonic susceptibility to RA teratogenicity under maternal diabetes: / To investigate these hypotheses, expression levels of various genes in different groups were compared. Result show that there are no significant differences in mRNA expression levels of CRABP-I, CRABP-II, RARgamma, RARgamma and RXRalpha between embryos of diabetic and non-diabetic mice with or without RA treatment. In contrast, expression levels of Raldh2 and CYP26 are significantly reduced in embryos of diabetic mothers, and in embryos of non-diabetic mice cultured in vitro in hyperglycemic conditions. Moreover, embryos of diabetic mice show significantly reduced response to RA-induced up-regulation of CYP26. These findings suggest that the rate of degradation of RA is slower in embryos of diabetic mice and thus the teratogenic effect of RA is enhanced. / Leung Bo Wah. / "July 2005." / Adviser: Alisa S. W. Shum. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3779. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 158-198). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.