Ovarian cancer is the most common cause of death from gynecological malignancy. Taxanes and platinum derivatives are most used therapeutics for its treatment. Development of multi drug resistance to chemotherapy represents a serious complication of the treatment. Therefore, new chemotherapeutic and therapeutic targets are investigated, which could help to overcome tumor cell resistance. The main objectives of the thesis were to study: i) the efficiency of new derivatives of conventional taxanes in vitro with the aim to determine the potentially most effective taxane derivatives in resistant tumor ovarian cells and, ii) the gene expression profile of the Notch signaling pathway, as a possible therapeutic target for the treatment of ovarian cancer. Specifically, the thesis focused on the relationship between levels of Notch signaling gene expression in patients with ovarian carcinoma and their prognosis, progression and survival. This thesis revealed that Stony Brook Taxanes - "SB-T"; SB-T-121402, SB-T-121605, and SB-T-121606 derivatives are very effective in NCI/ADR-RES tumor carcinoma cells resistant to conventional taxane - paclitaxel, and should be further studied in more advanced models, e.g. in vivo patient derived xenografts. In a study of the importance of the Notch signaling pathway in...

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21261号 / 医博第4379号 / 新制||医||1029(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 山下 潤, 教授 湊谷 謙司, 教授 羽賀 博典 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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The ophthalmic trigeminal placode (opV) exclusively gives rise to sensory neurons. A number of signaling pathways including Wnt, PDGF, FGF, and Notch are all involved in the progression of an undifferentiated cell in the opV placode to a proneural cell in the condensing opV ganglion. However, the regulatory relationships between these signal transduction pathways are still unknown. To determine if FGF activation acts to modulate Notch signaling in the sensory neurogenesis pathway, a novel multifactorial approach was employed: FGF signaling was inhibited in individual cells and globally with simultaneous inactivation of Notch signaling in chick embryos to investigate if FGF activation downregulates Notch thereby driving neurogenesis. These experiments resulted in few differentiating opV cells in the mesenchymal region of future ganglion formation suggesting an alternate regulatory relationship between FGF and Notch where either reduced Notch activity allows for FGFR4 expression (leading to FGF signaling and neurogenesis), or a parallel relationship where FGF and Notch act independently of one another to induce neurogenesis. To distinguish between these two possibilities Notch signaling was inhibited with DAPT, a gamma-secretase inhibitor, and assayed for FGFR4 mRNA expression. These results indicated FGFR4 is not upregulated by reduced Notch activity, suggesting that FGF and Notch act in parallel to promote neurogenesis. During these experiments it was observed that Notch inhibition resulted in an undefined ectoderm in the opV placode region. To investigate this, FGF and Notch were inhibited by SU5402, an FGF antagonist, and DAPT, and later sectioned and stained for Laminin. In DAPT treated embryos the basement membrane became highly fragmented, a remarkable observation not yet reported. From these data a proposed mechanism was established where activation of FGF with parallel downregulation of Notch leads to disruption of extracellular matrix proteins in the basement membrane resulting in fragmentation and subsequent delamination of differentiating opV placode cells.

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