Carlos M. Telleria - US grants

Prolactin (PRL) is an anterior pituitary hormone that regulates a variety of processes including lactation, immune response and reproduction. In the ovary PRL causes an increase in protein synthesis in the corpus luteum and sustains progesterone secretion. Although PRL stimulates the overall synthesis of proteins in the corpus luteum, it has a rather drastic inhibitory effect on few specific proteins within the 37-kD range. The 37 kD plays an important role in the tropic action of PRL in the corpus luteum. This protein with activity of 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) has a pivotal role in the termination of pregnancy and luteolysis. The overall goal of this investigation is to clarify the mechanism by which PRL transduces its message and inhibits the 20alpha-HSD gene activity. Aim 1. To examine the time course and dose response of PRL action on 20alpha-HSD gene expression. Luteinized granulosa cell culture will best suit these purposes. These cells express both 20alpha-HSD and the PRL receptor genes. Cells will be treated with different concentrations of PRL. Northern and Western analysis will be performed on the cells after different treatments to examine levels of 20alpha-HSD mRNA and protein. Aim 2. To examine whether JAK2 and Stat 91 are respectively the kinase and the transcriptional factor(s) associated with PRL signaling. JAK kinases and Stat 91 have been shown to be involved in the signal transduction of interferon-alpha, gamma and other members in the cytokine/erythropoietin family. PRL receptor (PRL-R) is also a member of this family, it is quite possible that it transduces its signal through similar pathway. The aims of these experiments will be: a) To find if PRL transduces its signal through JAK2 kinase, luteinized cells will be cultured in the absence or presence of PRL. Cell lysates will be immunoprecipitated with anti-JAK2. b) To further examine the relationship between PRL-R and JAK2, cell lysates obtained from cells treated +/- PRL will be immunoprecipitated with either anti-PRL-R or anti-JAK2. c) Phosphorylation of the PRL receptor and the non-receptor tyrosine kinases and other cellular proteins can be further demonstrated by in vivo phosphorylation. Cells will be incubated with PRL and [gamma- 32P]ATP, cell lysates will be subjected to immunoprecipitation with PRL-R antibody, JAK2 and Stat 91 antibodies and electrophoresis and autoradiography.

Abstract Not Provided.

[unreadable] DESCRIPTION (provided by applicant): The overall goal of this application is to study the feasibility of using the prototypical progesterone receptor modulator mifepristone, also known as "RU486," for ovarian cancer therapeutics. Ovarian cancer is the leading cause of death in women from gynecologic diseases, in part because of the difficulty in performing early diagnosis, and also due to the lack of successful treatment strategies. Treatment for ovarian cancer generally involves cytoreductive surgery followed by platinum-based chemotherapy, yet the major barrier that this treatment encounters is the development of chemoresistance, which leads to therapeutic failure. It is therefore clear that new therapeutic options for patients with advanced disease are desperately needed. Our preliminary data have demonstrated that mifepristone not only is a cytostatic agent for ovarian cancer cells, but also enhances the cytotoxicity of the standard chemotherapeutic agent cisplatin. These results led to the hypothesis that mifepristone can be exploited therapeutically in two manners: first as a cytostatic agent blocking the repopulation of cells that had survived chemotherapy; and second, enhancing chemotherapy-induced lethality. Specific aim 1 will identify the underlying molecular mechanism of the cytostatic effect of mifepristone in cultured ovarian cancer cells, and will test the efficacy of the compound in an in vivo setting using immunocompromised mice. Specific aim 2, using ovarian cancer cell lines of similar genetic backgrounds but carrying different sensitivities to cisplatin, will define whether mifepristone prevents repopulation of cancer cells in between rounds of cisplatin chemotherapy and the mechanism whereby it enhances cisplatin-mediated lethality. Results from this investigation have the potential for a major impact on human health because combination of mifepristone with standard cytotoxic chemotherapy would allow a reduction in the effective dose of cytotoxic drugs leading to reduced toxic side effects, lower chemoresistance and longer survival. At present there is no hormonal therapy approved for the treatment of any type of ovarian malignancy, yet the rationale of our preliminary results suggest that mifepristone is a promising hormonal therapeutic agent to be added to the list of anti-epithelial ovarian cancer drugs with the final goal of converting this lethal cancer into a treatable chronic disease. [unreadable] [unreadable] [unreadable]

(aa Beta, 17 beta)-11-[4-(dimethylamino)-phenyl]-17-hydroxy-17-(1-propynyl)estra-4,9-dien-3-one; 11 Beta-[4-(N,N-dimethylamino)phenyl]-17alpha-(propyl-1-ynyl)-delta-4,9-estradiene-17 beta-ol-3-one; CRISP; Cancer of the Ovary; Cancers; Cell Growth Inhibitors; Clinical; Computer Retrieval of Information on Scientific Projects Database; Contraceptive Agents; Contraceptives; Disease; Disorder; Drug usage; Drugs; Estra-4,9-dien-3-one, 11-(4-(dimethylamino)phenyl)-17-hydroxy-17-(1-propynyl)-, (11beta,17beta)-; Feasibility Studies; Funding; Generalized Growth; Goals; Grant; Growth; Growth Inhibitors; Human; Human, General; Institution; Investigators; Label; Laboratories; Malignant Cell; Malignant Neoplasms; Malignant Ovarian Neoplasm; Malignant Ovarian Tumor; Malignant Tumor; Malignant Tumor of the Ovary; Malignant neoplasm of ovary; Mammals, Mice; Man (Taxonomy); Man, Modern; Medical; Medication; Mice; Mifegyne; Mifeprex; Mifepristone; Murine; Mus; NIH; National Institutes of Health; National Institutes of Health (U.S.); Pharmaceutic Preparations; Pharmaceutical Preparations; Politics; Property; Property, LOINC Axis 2; Publishing; Purpose; R 38486; R38486; RU-38486; RU-486; RU38486; RU486; Research; Research Personnel; Research Resources; Researchers; Resources; Source; Steroid Compound; Steroids; Tissue Growth; United States National Institutes of Health; Unspecified Abortion; abortion; anticancer research; cancer cell; cancer research; design; designing; disease/disorder; drug use; drug/agent; experiment; experimental research; experimental study; malignancy; neoplasm/cancer; ontogeny; ovarian cancer; preclinical study; research study

DESCRIPTION (provided by applicant): The overall goal of this application is to study the feasibility of repositioning antiprogestin compounds originally designed for contraceptive purposes for ovarian cancer therapeutics. Ovarian cancer is the most deadly disease of the reproductive tract in women. When the disease is diagnosed, in most cases abnormal growths have already progressed beyond the confines of the ovaries and into the nearby fallopian tubes, uterus, and various other sites within the peritoneal cavity. As a result, the majority of patients diagnosed with ovarian cancer require surgery followed by platinum-based chemotherapy. Yet the efficacy of this therapy is hindered by the elevated toxicity of platinum derivatives, the repopulation of cells between treatment intervals, and the development of mechanisms to evade drug toxicity. Thus, the discovery of therapeutic interventions to overcome the limitations of platinum-based therapy is of critical clinical relevance. Our laboratory demonstrated that single therapy with the prototypical antiprogestin mifepristone inhibits growth of ovarian cancer cells in vitro as well as in a preclinical in vivo animal model of ovarian cancer. We have recently proved that the antiprogestin agents ORG-31710 and CDB-2914 also inhibit ovarian cancer growth. Finally, our preliminary data indicate that presence of the antiprogestin mifepristone after courses of lethal doses of cisplatin prevents repopulation or regrowth of remnant ovarian cancer cells surviving cisplatin treatment by potentiating cisplatin lethality. These results led to the hypothesis that antiprogestins can be exploited therapeutically in ovarian cancer enhancing the efficacy of platinum-based chemotherapy. To test the hypothesis, Specific Aim 1 will investigate whether antiprogestin mifepristone improves the therapeutic efficacy of cisplatin in vivo using orthotopic mouse models of ovarian cancer resembling two key stages of the disease including primary growth within the ovary and secondary dissemination in the peritoneal cavity (metastasis). Specific Aim 2 will elucidate the molecular mechanism whereby antiprogestins potentiate platinum lethality in ovarian cancer cells with particular emphasis on the DNA damage/repair pathways, and will determine whether progesterone receptors are required for the potentiation by antiprogestins of platinum-induced lethality. Specific Aim 3 will assess the mechanisms involved in antiprogestin-mediated growth inhibition of ovarian cancer cells that had repopulated after escaping the toxicity of platinum, and define the long-term fate of cells chronically exposed to antiprogestins after platinum escape. These pre-clinical studies will provide proof-of-principle that antiprogestins -of which mifepristone is FDA approved for reproductive medicine- can be repurposed for another modality-of-use as part of the chemotherapeutic armamentarium for ovarian cancer patients with the final goal of improving their quality and quantity of life, and significantly extending the 5-yr survival rate of this devastating disease. PUBLIC HEALTH RELEVANCE: Ovarian cancer is the most deadly disease of the female reproductive tract and has historically been called the silent killer. This research proposal will study whether antiprogestin drugs originally designed for contraceptive purposes can be exploited therapeutically enhancing the efficacy of platinum-based chemotherapy for ovarian cancer. Accomplishment of this project is anticipated to have high impact on a critical health care problem as ovarian cancer still is the most deadly of all gynecologic diseases and no significant therapeutic breakthrough has occurred during the past three decades. The completion of the pre-clinical studies described in this proposal will lead to the rational design of clinical trials including an antiprogestin for the treatment of ovarian cancer with the final purpose of improving the quality and quantity of life of patients, and converting this lethal cancer into a manageable chronic disease.