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: This Award funded the initiation of a mentored research experience in ovarian cancer biology at the Dana Farber/Harvard Cancer Center. The primary aims, articulated in the Statement of Work, included creating a mechanism to identify and select outstanding postdoctoral fellows who had a commitment to serious multi-year experience in research that was directly related to a topic in or immediately applicable to ovarian cancer. The second aim was to provide a mentored experience for selected fellows. The third aim specified the delivery of feedback to the trainees by mentors and the program PI. The final aim described a rigorous review process for the program. These aims are all being addressed. Of the four senior post doctoral fellows selected to work with Faculty at Harvard Medical School in the fields of oncogenesis, signal transduction, pathology and mouse models and cell biology, one fellow graduated from the program and is successfully transitioning towards an independent academic research career. The vacancy was competed for and filled successfully. A new faculty member with extensive training in biologic models was added to the program to mentor the fellows, who continue to pursue their research productively at 3 different institutions within the Dana Farber/Harvard Cancer Center. Given that early stage ovarian cancer is largely curable, new approaches to early detection are needed to achieve lower ovarian cancer morbidity and mortality. A sensitive and specific screening test that could detect ovarian cancer at a curative stage has yet to be developed. The application of cDNA and oligonucleotide microarrays analyses to ovarian cancer has resulted in the identification of many genes that are overexpressed in primary tumors and ovarian mTOR (mammalian target of rapamycin) is an evolutionary conserved serine/threonine kinase that integrates inputs from nutrients, growth factors and cellular energy status and coordinates cell growth and proliferation via the regulation of protein synthesis. Increased rate of translation is essential for maintenance of rapid rates of cell division and is thus an interesting target for therapeutic intervention in malignant diseases. The preliminary results from ongoing clinical trials with rapamycin analogues CCI-770 and RAD001 indicate that inhibition of mTOR signaling has promising antitumor activity with relatively minor toxicities. The objective of our study was to compare relative contribution of mTOR and its effectors S6K1 and eIF4E to tumor progression and to evaluate their potential as therapeutic targets in epithelial ovarian cancer. In addition we examined their role in modulation of chemosensitivity. Initial analysis was done active Akt/mTOR expression. Retroviruses used to stably the above kinases or scrambled-control shRNA. At least two distinct shRNAs were tested for each target. Those inducing the most potent knockdown were chosen for further analysis. Total amounts and phosphorylation states of targeted proteins were assessed with immunoblotting. MTS assay was used for the analysis of cell viability and proliferation rate. Preliminary results indicate differential contribution of each target to proliferation rate and chemosensitivity. While rapamycin had no significant impact on paclitaxel sensitivity in nanomolar range, stable reduction of mTOR expression increased sensitivity to paclitaxel several fold. Cisplatin sensitivity was not significantly altered in any of the stable cell lines. This data is consistent with the recent report showing that rapamycin enhances sensitivity to cisplatin only in tumor cells with wild-type p53. (SKOV3 cells are p53 -null). Müllerian duct regression during mammalian embryogenesis is critical for male differentiation. In mammalian males, the fetal testes produce and secrete Müllerian Inhibiting Substance (MIS), which causes the Müllerian (paramesonephric) ducts to regress. In the absence of MIS, Müllerian ducts continue to develop and differentiate as the oviduct, uterus, cervix, and upper part of the vagina. Müllerian duct dissolution is initiated by binding of MIS to its specific type II receptor (MISRII) in the surrounding mesenchymal cells. The type II receptor then signals downstream through specific type I receptors and receptor-specific Smads, which remain to be elucidated in MIS signaling. Dr. Zhan’s research demonstrates that expression of ALK2 (a candidate type I receptor), Smad8 Hepsin is an integral plasma membrane protease that contains a catalytic C-terminal domain facing the cell surface and an N-terminal domain facing the cytosol. Hepsin is widely expressed in different tissues and cell types, with prominent expression in the liver and kidney. The high expression of hepsin is associated with several types of cancer, including ovarian carcinoma. In order to gain insight into its function, we studied the subcellular localization and expression of hepsin in ovarian cancer tissues and cell lines. Immunofluorescence analysis showed that hepsin co-localizes with desmoplakin at the cell membrane, where it is linked to keratin filaments at desmosomal junctions. Surprisingly, hepsin is also localized in nucleoli, where it co-localizes with the nucleolar protein UBF, which is involved in ribosome synthesis. Western blot analysis was used to investigate the protein level of hepsin in mouse and human tumor cell lines. Consistent with the hypothesis that the mature form of hepsin is derived from a single-chain zymogen that is processed by cleavage or by shedding from the plasma membrane, proteins of different molecular weights were observed on SDS-PAGE. In order to study the role of hepsin in tumor progression, we generated mouse ovarian cancer cell lines that express GFP, hepsin or a catalytically-inactive hepsin mutant protein, and showed that hepsin promotes tumor formation and metastases in immunocompetent mice. The proteolytic function of hepsin was required for promoting tumor progression. Together with previous data showing upregulation of hepsin in ovarian tumors, our data strongly imply a role for hepsin in the progression of ovarian cancer.