Maternal-embryo interactions at the time of implantation in early pregnancy / by Tina Christine Lavranos.

1 v.Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 199

Trophic effects of myeloid leukaemia inhibitory factor (LIF) on mouse embryos

Myeloid leukaemia inhibitory factor (LIF) is expressed at highest concentrations in the maternal endometrial glands at about the stage of blastocyst implantation. LIF is also expressed by the extraembryonic membranes of the early mouse embryo. Embryos of different ages were cultured with, or without, LIF, and embryo growth in vivo and in vitro was examined to determine whether LIF is important for embryo development. Supplementing embryo culture media with 1000 U recombinant human LIF ml−1 increased the number of eight-cell mouse embryos developing beyond the hatched blastocyst stage in vitro from 62.1% to 85.1% (P < 0.05). LIF significantly increased the number of embryos hatching (33.8% versus 7.65% for controls 96 h after hCG injection, P < 0.001), completely hatching (85.1% versus 62.1%, P < 0.05), and exhibiting trophoblast outgrowth (13.5% versus 0% 120 h after hCG treatment, 85.1% versus 47.0% 144 h after hCG treatment, P < 0.001) in vitro. LIF-treated embryos also displayed a significantly greater area of trophoblast outgrowth than did controls as early as day 5 in culture (P < 0.005). These data show that LIF enhances mouse eight-cell embryo development in vitro, as seen by the accelerated rate of embryo hatching and trophoblast outgrowth. In addition, enhanced embryo survival in vivo is shown, following the transfer of LIF-treated embryos into a pseudopregnant recipient female. Expression of mRNA encoding LIF was detected in endometrial cells cultured in monolayer from uteri of day 3 pregnant females, explaining the known embryotrophic effects of endometrial coculture. This expression was not enhanced significantly by treatment with oestradiol (3.7 × 10−5 mol l−1) or progesterone (3.2 × 10−6 mol l−1) or both hormones. These results indicate that LIF could have a dual action in early embryogenesis as an embryotrophin and as a factor required for embryo implantation. Multiple roles for LIF are consistent with the expression of this factor at embryonic, extraembryonic and maternal sites during early embryogenesis.T. C. Lavranos, P. D. Rathjen, and R. F. Seamar

BNC105: a novel tubulin polymerization inhibitor that selectively disrupts tumor vasculature and displays single-agent antitumor efficacy

Vascular disruption agents (VDA) cause occlusion of tumor vasculature, resulting in hypoxia-driven tumor cell necrosis. Tumor vascular disruption is a therapeutic strategy of great potential; however, VDAs currently under development display a narrow therapeutic margin, with cardiovascular toxicity posing a dose-limiting obstacle. Discovery of new VDAs, which display a wider therapeutic margin, may allow attainment of improved clinical outcomes. To identify such compounds, we used an in vitro selectivity screening approach that exploits the fact that tumor endothelial cells are in a constant state of activation and angiogenesis and do not undergo senescence. Our effort yielded the compound BNC105. This compound acts as a tubulin polymerization inhibitor and displays 80-fold higher potency against endothelial cells that are actively proliferating or are engaged in the formation of in vitro capillaries compared with nonproliferating endothelial cells or endothelium found in stable capillaries. This selectivity was not observed with CA4, a VDA currently under evaluation in phase III clinical trials. BNC105 is more potent and offers a wider therapeutic window. CA4 produces 90% vascular disruption at its no observed adverse event level (NOAEL), whereas BNC105 causes 95% vascular disruption at 1/8th of its NOAEL. Tissue distribution analysis of BNC105 in tumor-bearing mice showed that while the drug is cleared from all tissues 24 hours after administration, it is still present at high concentrations within the solid tumor mass. Furthermore, BNC105 treatment causes tumor regressions with complete tumor clearance in 20% of treated animals.Gabriel Kremmidiotis, Annabell F. Leske, Tina C. Lavranos, Donna Beaumont, Jelena Gasic, Allison Hall, Michael O'Callaghan, Clayton A. Matthews and Bernard Flyn

Phase I study of BNC105P, carboplatin and gemcitabine in partially platinum-sensitive ovarian cancer patients in first or second relapse (ANZGOG-1103)

Purpose: The primary objective of this study was to determine the recommended dose of the vascular disrupting agent, BNC105P, in combination with gemcitabine and carboplatin in patients with ovarian cancer in first or second relapse with a minimum 4 month progression-free interval after last platinum. Methods: Patients received carboplatin AUC4 on day 1 in combination with escalating doses of 800 or 1000 mg/m2 gemcitabine on days 1 and 8 and escalating doses of 12 or 16 mg/m2 BNC105P on days 2 and 9 every 21 days for a maximum for six cycles. Maintenance treatment with 16 mg/m2 BNC105P treatment continued for a maximum of six additional cycles. Patients were followed for safety and anti-tumor activity. Results: Fifteen patients were enrolled in the study. Adverse events were most commonly of hematological origin. Dose-limiting toxicities (thrombocytopenia and neutropenia) occurred in two patients at the dose level of 800 mg/m2 gemcitabine, carboplatin AUC4 and 16 mg/m2 BNC105P. No dose-limiting toxicities were observed at a dose level of gemcitabine 1000 mg/m2, carboplatin AUC4 and BNC105P 12 mg/m2. BNC105P as a single agent was well tolerated at a dose of 16 mg/m2 in maintenance treatment. Ten patients (67%) achieved a complete or partial response according to CA125 and/or RECIST response criteria, four of 13 (31%) responded by RECIST alone. The median progression-free survival was 5.9 months. Conclusions: We have established that BNC105P 12 mg/m2 with gemcitabine 1000 mg/m2 and carboplatin AUC4 is the recommended dose level and has an acceptable toxicity profile. Further exploration of BNC105P in the ovarian cancer setting is planned