Epithelial ovarian cancer (EOC) is the leading cause of death from gynecological malignancy in Western countries. A better understanding of the etiology and risk factors associated with this disease is crucial for the development of early detection protocols as well as more effective therapies. Epidemiological data has shown that the risks of EOC are highest among peri- or post- menopause women, while increased parity or the use of oral contraceptives is preventive. These data suggest that alterations in reproductive factors are associated with ovarian cancer risks; however, the molecular mechanisms underlying such a link remain to be understood. For decades, EOC was believed to arise from the epithelium that surrounds the ovarian surface, yet this concept fails to explain the morphological resemblance of ovarian epithelial neoplasms with the epithelial cells of the Müllerian-derived female reproductive tract. Alternative ideas have argued that EOC may originate from extra- or para-ovarian tissues such as the fallopian tube and ovarii rete. Studies of the origin of EOC will provide a better understanding of the disease and advance the protocols for early diagnosis. The aims for this thesis are to establish in vivo ovarian tumor models based on the germ cell deficient Wv/Wv mice that mimicking menopausal physiology. The Wv mice harbor a point mutation in c-Kit, which reduces its tyrosine kinase activity to about 1%, resulting in a premature loss of ovarian germ cells and follicles that recapitulates the initiation of menopause in human. We have developed ovarian tumor models by deleting the tumor suppressor genes p53 or p27kip1 in Wv/Wv mice. We found that both Wv/Wv:p27+/- and Wv/Wv :p27 -/- mice developed ovarian epithelial tumors, which consist of papillary structures lined by hyperchromatic neoplastic cells. Positive Cytokeratin 8 (CK8) staining indicated the epithelial origin of these tumors. In vitro primary cultures of mouse ovarian surface epithelial (MOSE) cells from wildtype, p27+/- and p27 -/- mice further confirmed the growth advantage caused by p27 deficiency. However, neither p27 +/- nor p27 -/- MOSE cells were transformed in vitro, probably due to the compensatory increase of cyclin dependent kinase inhibitor (CKI) proteins including p21, p16, p19. When p53 was deleted unilaterally in the ovarian surface epithelial cells of Wv/Wv:p53 loxP/loxP mice by single administration of Adenovirus containing Cre activity (Ad-Cre), ovarian tumors developed after long latency. The ovarian tumors were significantly enlarged when compared with the uninfected ovary from the same mouse. However, most of the lesions in Wv:p53 conditional knockout tumors was negative for epithelial and follicular markers. In vitro deletion of p53 in MOSE cells significantly increased the proliferation and passage numbers of these cells. A compensatory increase of the CKI protein p16, as well as the cellular senescence level was also observed in p53 deleted MOSE cells, suggesting that p53 deletion alone was not sufficient to bypass p16- mediated tumor defense mechanisms in MOSE cells. Taken together, single deletion of p27 and p53 significantly amplified the phenotype of benign tubular adenomas in Wv/Wv mouse. However, neither p27 nor p53 deletion was sufficient to induce the development of malignant ovarian carcinomas in Wv/Wv mice, probably due to the up-regulation of CKI family proteins such as p21, p16 or p19.

<p>The objective of this research was to assess ultrasound image attributes of human dominant ovarian follicles in the final stages of development during natural and oral contraceptive (OC) cycles, as well as characterize ovarian follicular and endometrial development during and after continuous versus conventional dosing schemes. We utilized sophisticated computer algorithms to elucidate an association between image attributes and physiologic status of follicles in their final stage of development. We used transvaginal ultrasonography to quantify changes in the numbers and diameters of ovarian follicles and changes in endometrial thickness and pattern during and following discontinuation of two different regimens of OC. Developmental changes in ovarian follicles and corpora lutea were correlated with serum estradiol-17â and progesterone, respectively to provide a comprehensive approach to examining ovarian and uterine function. </p><p>We reported for the first time that follicles which develop during natural and OC cycles have similar image attributes, which provides preliminary evidence that image attributes of human follicles are associated with physiologic status during the growth phase. Further research should be performed to elucidate the exact correlation between image attributes during all stages of follicular development throughout the menstrual cycle, prediction of dysfunctional follicular development (i.e., hemorrhagic anovulatory follicles) and the effects of different OC formulations on follicle development. Once the association between image attributes and various scenarios of follicular development are determined, a computer program could be developed to assess follicular health with a single ultrasound examination, obviating many ethical constraints that currently prevent large scale progress in ovarian follicular research. We further documented that continuous OC administration schemes provide greater follicular suppression than conventional dosing schemes. No dominant follicles developed during three consecutive 28 day cycles of continuous OC use, whereas eight dominant follicles developed during the same time period of conventional OC use. We interpreted these findings to mean that continuous OC dosing schemes provide a more effective contraceptive with a decreased risk of escape ovulation compared to conventional dosing schemes. Most follicles ovulated in the immediate cycle following discontinuation of OC. We suggest that the delay to fertility following cessation of OC is not due to anovulation but other yet, unknown, biological factors. </p>

Ovarian cancer remains the deadliest gynecologic malignancy. Current treatment has low efficacy in the long term, leading to low 5-year survival rates of 20-40%. Treatment-free periods between cycles of chemotherapy are accepted in standard treatment. These periods lead to accelerated tumor cell proliferation, angiogenesis and drug resistance development. Studies presented herein show advantages of continuous carboplatin dosing schedule over conventional intermittent regimen, both administered intraperitoneally. Continuous carboplatin therapy blocked acceleration of cell proliferation observed during treatment-free period of intermittent therapy. Moreover, continuous carboplatin led to 57% inhibition of SKOV3 tumors grown intraperitoneally in SCID mice, a significant advantage over the 33% tumor suppression observed with intermittent carboplatin. Immunohistochemical analysis revealed continuous carboplatin led to greater tumor cell death while suppressing tumor cell proliferation and angiogenesis when compared to intermittent administration. These results show that the suppression of tumor growth with carboplatin can be enhanced by the elimination of treatment free periods.

Ovarian cancer remains the deadliest gynecologic malignancy. Current treatment has low efficacy in the long term, leading to low 5-year survival rates of 20-40%. Treatment-free periods between cycles of chemotherapy are accepted in standard treatment. These periods lead to accelerated tumor cell proliferation, angiogenesis and drug resistance development. Studies presented herein show advantages of continuous carboplatin dosing schedule over conventional intermittent regimen, both administered intraperitoneally. Continuous carboplatin therapy blocked acceleration of cell proliferation observed during treatment-free period of intermittent therapy. Moreover, continuous carboplatin led to 57% inhibition of SKOV3 tumors grown intraperitoneally in SCID mice, a significant advantage over the 33% tumor suppression observed with intermittent carboplatin. Immunohistochemical analysis revealed continuous carboplatin led to greater tumor cell death while suppressing tumor cell proliferation and angiogenesis when compared to intermittent administration. These results show that the suppression of tumor growth with carboplatin can be enhanced by the elimination of treatment free periods.

<p>The objective of this research was to assess ultrasound image attributes of human dominant ovarian follicles in the final stages of development during natural and oral contraceptive (OC) cycles, as well as characterize ovarian follicular and endometrial development during and after continuous versus conventional dosing schemes. We utilized sophisticated computer algorithms to elucidate an association between image attributes and physiologic status of follicles in their final stage of development. We used transvaginal ultrasonography to quantify changes in the numbers and diameters of ovarian follicles and changes in endometrial thickness and pattern during and following discontinuation of two different regimens of OC. Developmental changes in ovarian follicles and corpora lutea were correlated with serum estradiol-17â and progesterone, respectively to provide a comprehensive approach to examining ovarian and uterine function. </p><p>We reported for the first time that follicles which develop during natural and OC cycles have similar image attributes, which provides preliminary evidence that image attributes of human follicles are associated with physiologic status during the growth phase. Further research should be performed to elucidate the exact correlation between image attributes during all stages of follicular development throughout the menstrual cycle, prediction of dysfunctional follicular development (i.e., hemorrhagic anovulatory follicles) and the effects of different OC formulations on follicle development. Once the association between image attributes and various scenarios of follicular development are determined, a computer program could be developed to assess follicular health with a single ultrasound examination, obviating many ethical constraints that currently prevent large scale progress in ovarian follicular research. We further documented that continuous OC administration schemes provide greater follicular suppression than conventional dosing schemes. No dominant follicles developed during three consecutive 28 day cycles of continuous OC use, whereas eight dominant follicles developed during the same time period of conventional OC use. We interpreted these findings to mean that continuous OC dosing schemes provide a more effective contraceptive with a decreased risk of escape ovulation compared to conventional dosing schemes. Most follicles ovulated in the immediate cycle following discontinuation of OC. We suggest that the delay to fertility following cessation of OC is not due to anovulation but other yet, unknown, biological factors. </p>

No description available.

Metastatic dissemination of ovarian tumors involves the invasion of multi-cellular tumor cell clusters into the mesothelial cell lining of organs in the peritoneal cavity. We developed an in vitro assay that models this initial step of ovarian cancer metastasis to investigate the mechanisms of invasion. Pre-clustered ovarian cancer multicellular spheroids are incubated with GFP-expressing mesothelial monolayers and the extent of mesothelial invasion is monitored by time-lapse video microscopy.

This thesis is an investigation of the use of thrombospondin-1 mimetic peptides for the treatment of epithelial ovarian cancer. The current standard of care for women diagnosed with ovarian cancer is surgical de-bulking followed by chemotherapeutics. Initially, this treatment regimen results in a reduction in the primary tumor, unfortunately chemoresistance and disease recurrence are problematic. Recent data has suggested a potential role for anti-angiogenic therapy for the treatment of various cancers. Therefore, the purpose of this study was to investigate the use of mimetics consisting of the anti-angiogenic domain of thrombospondin-1 (TSP-1) for the treatment of epithelial ovarian cancer (EOC) using a mouse model of the disease. The peptides were applied at various stages of tumor progression and a significant reduction in tumor size following treatment was observed. We found that not only were the peptides capable of slowing down tumor progression but they also played a role in reducing the size of established tumors. Treatment with TSP-1 mimetics also resulted in a significant reduction in secondary lesions and ascites fluid in the peritoneal cavity of animals. A significant increase in disease-free survival was also identified following long-term treatment with the peptide. Various histological studies revealed that the anti-angiogenic peptide was in fact inducing apoptosis of the endothelial cells and also re-organizing the vasculature. To determine whether this resulted in increased blood vessel profusion we applied standard chemotherapeutics in combination with TSP-1 mimetics. Experiments with radiolabelled and fluorescent chemotherapeutics demonstrated that pre-treating with TSP-1 mimetics allowed the vasculature to become normalized and resulted in an increased uptake of chemotherapeutics. Lastly, we investigated the mechanism of action of anti-angiogenic peptides. Most of the anti-tumor effects appeared to be due to the apoptotic effects of TSP-1 mimetics on the vasculature. A direct apoptotic effect on epithelial cells also was observed; however, it is uncertain how much of a role this plays. In conclusion, this study was important for identifying TSP-1 mimetic peptides as a potential therapeutic treatment for women suffering from EOC.

Ovarian cancer is the deadliest gynaecologic cancer in New Zealand. Its high mortality rate is due to the fact that it is usually diagnosed at an advanced stage. Advanced ovarian cancer is less responsive to current cytotoxic treatment. Thus, there is an urgent need for novel anti-cancer drugs that can improve patient longevity and quality of life. One of the clinical features of advanced ovarian cancer is the growth of secondary tumours due to the highly metastatic nature of the disease. Cancer cells disseminate from the ovary, some form cell clusters that travel through the abdominal cavity by physiological movement of body fluid and then deposit on the abdominal wall and internal organs to generate secondary tumours. The exact mechanisms of how these cells metastasize are unclear, but prognosis typically worsens if levels of vascular endothelial growth factor (VEGF) are elevated. This study investigated the anti-tumour activities of naturally occurring food compounds resveratrol, acetyl resveratrol and (-)-Epicatechin-3-gallate (EGCG), in cell spheroids/clusters of ovarian cancer. It also examined the protein expression of various proteins involved in the NF-κB signalling pathway. This pathway has been suggested to mediate the secretion of VEGF and is a possible target for the naturally occurring compounds. Results show that resveratrol and acetyl resveratrol reduce cell growth and cellular metabolism in a dose-, time- and cell line- dependent fashion. In addition, the reduction of VEGF is also dose-, time- and cell line- dependent. Paradoxically, another angiogenic protein interleukin-8 (IL-8) secretion is increased. Resveratrol and acetyl resveratrol attenuate the expression of NF-κB but this effect is cell line specific. EGCG has limited effect on cell growth, cellular metabolism and the secretion of VEGF and IL-8. These findings suggest that resveratrol and its derivative may have the ability to supress the angiogenic activity of ovarian cancer cells and warrant further in vivo study.

No description available.