Regulation of gene expression is a complex process in mammalian cells with many levels of control. In recent years non-coding RNAs in the form of microRNAs (miRNA) have surfaced as important regulators of protein coding genes, with biologically important roles in development, differentiation and cell growth. In this dissertation the complex interactions between miRNAs and mRNAs in ovarian cancer are investigated using a combination of computational and experimental techniques. In vitro studies and current models predict that increases in levels of miRNA should result in corresponding decreases in the levels of targeted mRNAs due to miRNA induced degradation. Profiling the global miRNA and mRNA expression patterns in epithelial ovarian cancer cells from patients and surface epithelial cells from normal ovaries reveal only ~11% of predicted targets of miRNAs are inversely correlated in vivo. In an effort to dissect the mechanisms behind these unexpected observations single miRNA transfection experiments are carried out followed by gene expression profiling. Analysis of genes altered following these transfections reveal majority of the altered genes are not direct targets of the miRNAs. Network analysis however suggests that miRNAs may target "hub genes" to cause altered expression in downstream transcripts. Pathway enrichment analysis of altered genes demonstrates miRNAs may regulate specific pathways rather than causing random off-target effects. Finally investigation of miRNA regulation reveals miRNAs may also affect the levels of other miRNAs, which may indirectly affect more genes downstream. Together these results provide a detailed view of the mechanisms employed by miRNAs to regulate the expression of hundreds of genes in ovarian cancer cells.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / Obstetrics and Gynaecology / Master / Master of Philosophy

published_or_final_version / Biological Sciences / Master / Master of Philosophy

Ovarian cancer is one of the most deadly female malignancies. Despite advances in the treatment of ovarian cancer for the past decade, the cure rate of this disease is moderately improved. Emerging evidence suggests the molecular personalized therapeutic approach become popular for human cancer treatment. The nuclear factor-kappa B (NF-κB) signaling pathway has been shown to play multiple roles in cancer progression such as anti-apoptosis, cell cycle, angiogenesis and metastasis. This study attempted to characterize the functional roles of transforming growth factor (TGF)-β-activating kinase 1 (TAK1) in the activation of NF-κB signaling. Importantly, this study provided evidence showing the significance of TAK1-NF-κB signaling axis in ovarian cancer aggressiveness during omental metastasis. Using quantitative RT-PCR and immunohistochemical analyses, TAK1 was frequently up-regulated and was significantly associated with high-grade (P=0.001), lymph node and distant metastasis (P=0.025), as well as a tendency toward advanced stage ovarian cancers (P=0.08). Functionally, enforced expression of TAK1 could augment cell proliferation, colony formation, anchorage-independent growth ability and migration/invasion in ovarian cancer cells. Conversely, repression of TAK1 expression by genetically or pharmaceutical approach abrogated these tumorigenic capacities including tumor growth in vivo. Furthermore, co-treatment of (5Z) -7-Oxozeaenol could sensitize ovarian cancer cells to cisplatin-induced cell apoptosis, indicating TAK1 is also involved in chemoresistance. Mechanistically, using Western blotting and NF-κB -reporter luciferase analyses, the elevation of TAK1 phosphorylation at Ser412 but not Thr184/187 was found to associate with the activation of NF-κB in ovarian cancer cells solely. A series of functional studies with genetic and pharmaceutical alterations revealed that the increased TAK1 Ser412 phosphorylation was required for exerting the ovarian cancer cell oncogenesis. Omental metastasis is the common phenomenon observed in most of advanced-stage ovarian cancer. Using omentum conditioned medium (OCM), the findings of this study showed that the omentum tissue was able to secrete numerous factors including chemokines such as GRO-α and IL8 in activating TAK1-NF-κB signaling cascade, which thereby induced increased oncogenic capacities in cell growth, migration and invasion. Taken together, this study suggests that TAK1-NF-κB signaling axis is indispensable for promoting oncogenesis of ovarian cancer and targeting this pathway may be a promising personalized cancer therapeutic approach in ovarian cancer. / published_or_final_version / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

Measurements of ovarian, corpus luteum, follicles of Lithuanian Black and White and German Black and White breed cows made by ultrasound scanner were revised. Effect of different factors, such as age, breed and season determining persistence of corpus luteum was statistically evaluated. Validation of treatment efficacy of persistent corpus luteum was carried out based on testing of progesterone concentration in peripheral blood plasma.

Darbas atliktas Lietuvos Sveikatos Mokslų Universiteto Veterinarijos Akademijos Patologijos centre nuo 2012 metų sausio iki 2013 metų spalio mėnesio. Darbo tema: Kačių ovariohisterektomijos statistinių duomenų ir gimdos bei kiaušidžių patomorfologinių tyrimų analizė. Tyrimo tikslas - atlikti kačių ovariohisterektomijos statistinių duomenų ir gimdos bei kiaušidžių patomorfologinių tyrimų analizę. Tyrimo tema aktuali dėl vis didėjančio kačių reprodukcijos susidomėjimo, siekiant susilaukti sveikų palikuonių. Tyrimų objektas – katės (patelės, Felis catus), kurioms buvo atlikta OHE. Ištirti 227 kačių organai (n=227), ir apklausius jų šeimininkus, surinkti statistiniai duomenys. Vertinamos kiaušidės ir gimda, jų topografija, dydis, spalva, konsistencija, kvapas ir forma. Organai vertinami iš išorės, vėliau pjūvyje. OHE metu, įtarus patologijas, paimti kiaušidžių ir gimdos mėginiai histopatologiniam tyrimui. Ištirta 16 kačių kiaušidžių ir 13 gimdų. Mėginiai dažyti hematoksilinu ir eozinu. Kiaušidžių ir gimdos patologijos katėms diagnozuojamos retai (apie 7 proc.) ir dauguma aptinkamos rutininės OHE metu. Kiaušidėse dažniausiai aptinkami pakitimai - cistos, gimdoje - piometra. Vidutinis kačių, sergančių piometra amžius - 6 metai. Statistiniai duomenys apskaičiuoti Microsoft Office Excel 2007. Darbo apimtis - 56 puslapiai, naudoti 47 literatūros šaltiniai, 6 lentelės, 34 paveikslai. / This work was carried out in the period of 2012 January to 2013 October at the Pathology Center of the Veterinary Academy of the Lithuanian University of Health Sciences. The title of work is “The analysis of feline ovariohysterectomy statistics and ovarian and uterus pathomorphological researches”. The aim of the study: to perform cats OHE statistics and ovarian and uterus pathomorphological investigations analysis. The research theme is relevant due to increasing interest in feline reproduction, in order to have healthy offsprings. The object of study is the cats (female, Felis catus), which has been conducted OHE. There were examined 227 cats ovaries and uterus. Pet's owners were interviewed in order to get statistical data. Topography, size, color, texture, smell and shape of ovaries and uteruses were estimated. Organs were examined from the outside, later in the section. Samples for histopathological examination were taken due to suspected pathology. There were tested 16 cats ovaries and 13 uteruses. They were stained by hematoxylin and eosin. Cats ovary and uterus pathology are rare (about 7%) and diagnosed mostly by daily OHE. Cysts mostly are diagnosed in ovaries, in uterus – pyometra. Average age of cats with pyometra is 6 year. Average age of cats, which was operated – 30 months. OHE is performed to terminate cats reproduction. Statistical data analysis was rated by Microsoft Excel 2007. The volume of work is 56 pages, 6 tables and 34 pictures. Total count of... [to full text]

El penegal, Helicolenus dactylopterus dactylopterus (Pisces: Scorpaeniformes), és una espècie que habita profunditats d'entre els 200 i 1000 m i presenta una clara distribució batimètrica en funció de la seva talla. Presenta fecundació interna i a l'interior de l'ovari conté estructures d'emmagatzematge que permeten emmagatzemar l'esperma durant períodes de temps considerablement llargs. Les cèl·lules sexuals masculines es mantenen viables gràcies a diverses substàncies nutritives que obtenen de la bossa citoplasmàtica i de l'epiteli criptal que delimita les estructures d'emmagatzematge. Aquest epiteli és també responsable de la seva protecció. Un cop els ous han assolit la maduresa, els espermatozoides són alliberats al lumen ovàric i es dóna la fertilització. És una espècie zigòpara: allibera òvuls fecundats que han estat retinguts al tracte reproductiu femení durant un curt període de temps i, per tant, els embrions són alliberats en estadis molt primerencs de desenvolupament. Així, el penegal presenta una estratègia reproductiva evidentment eficaç. / The bluemouth, Helicolenus dactylopterus dactylopterus (Pisces: Scorpaeniformes), is a species that inhabits the seabed at depths between 200 and 1000 m and shows a clear size-dependent bathymetric distribution.It has internal fertilization and, inside the ovary, there are storage structures that allow it to store sperm for considerably long periods of time. These male sexual cells remain viable thanks to several nutritious substances they obtain from the cytoplasmic bag and from the cryptal epithelium that delimits the storage structures. This epithelium is also responsible for their protection. Once the eggs have reached maturity, the spermatozoa are freed in the ovarian lumen and fertilization occurs. This species is zygoparous: liberation of fertilized ova, which have been retained in the female reproductive tract during a short period of time and, therefore, the embryos are freed in very early stages of development. Thus, the bluemouth exhibits an obviously effective reproductive strategy.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 101-110). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 110-136). Also available on the Internet.