On completion of her MD (1999), Residency in OB-GYN (1999-2003, Johns Hopkins), two yrs of basic research training at the NCI (2003-05) followed by a Clinical and Research Fellowship in Gynecologic Oncology (2005-08, Cleveland Clinic), Dr. Simpkins was recruited to the University of Miami (UM) as Assistant Professor and physician scientist in the Division of Gynecologic Oncology and UM Sylvester Cancer Center. During her training, she completed 3 yrs of lab research, attended the AACR/ASCO Clinical Trial Design Workshop, and designed and executed a phase II ovarian cancer (OVCA) trial during fellowship. She began mentored research in Aug, 2008 in Slingerland's lab, investigating mechanisms of growth stimulation in OVCA by estrogens (E2) and signaling via Src, MEK and AKT. Dr. Simpkins has 75% protected research time and start-up funds to support initial project development to garner independent funding. The applicant's goals for the next 2-3 yrs are to deepen her knowledge of estrogen and growth factor signaling in OVCA, gain experience with pre-clinical drug development and predictive markers in OVCA, become proficient in grantsmanship and phase I trial design. Her career goal is to develop and implement innovative strategies in targeted therapy for Gyn malignancies and move seamlessly between lab and clinic. Dr. Simpkins has J. Slingerland MD, PhD as primary mentor, an expert in cell cycle, steroid hormone receptor biology and hormone resistant breast cancer and M. Pegram MD, an expert in pre-clinical and clinical development of molecular targeted cancer therapies, as co-mentor. The Cancer Center has a large multi- ethnic cancer patient base, a critical mass of multi-disciplinary basic scientists and clinicians with a translational track record, and offers admininistrative support and resources for clinical research. This K08 will foster Dr. Simpkins'development as a clinician scientist trained in molecular mechanistic research whose goal is to generate novel therapies and test them in clinical trials. A detailed training plan is proposed. OVCA is the most lethal gynecological malignancy. Most patients are diagnosed with advanced stage III/IV and recur within 2 yrs. Recurrent OVCA is incurable and goals are palliation of symptoms. Patients exhaust treatment options so new therapies are desperately needed. Anti-estrogen therapies are well tolerated and thus appealing in this setting. Such therapies have not yet been tested in early stage (IC/II) OVCAs and maybe of benefit in this setting as well. This project will potentially identify novel treatment options for OVCA. E2 drives OVCA growth in vitro and invivo12-15. E2 deprivation and estrogen receptor(ER) blockade because breast cancer (BRCA) cells to arrest in the G1 phase of the cell cycle16, 17. Cell cycle progression is governed by cyclin-dependent kinases (cdks) that are activated by cyclins and inhibited by cdk inhibitors. The cdk inhibitors, p21 and p27, are cycle negative regulators that are frequently reduced in many cancers, including OVCAs16, 17. The ER is expressed in the majority of OVCAs, similar to BRCA18. Anti-estrogen effects on survival and cell cycle in OVCAs have not been characterized. Despite high ER expression in OVCAs, small trials of anti-estrogen therapies have been disappointing. The benefit of anti-estrogens has not been studied in large well-designed OVCA trials. In OVCAs, many patients manifest de novo resistance to anti-estrogens and those that do initially respond, invariably develop resistance. Src, Ras/Raf/MEK and PI3K pathways are constitutively activated in OVCAs.1 My preliminary data and that of others support the notion that cross talk between estrogen-bound ER and signaling kinases leads to Src and MEK/MAPK activation to stimulate cell cycle progression, 17, 34. Our preliminary data show that E2 stimulates further activation of Src, MEK and AKT in ER+ OVCA lines. Combined Src inhibitor with ER blockade caused a greater G1 arrest of ER+ OVCA cells through increased levels and action of p27. Moreover, use of both Src and MEK inhibitor drugs more effectively arrested cells in G1 than monotherapy, with inhibition of Src, MAPK and AKT and increased p27 levels causing inhibition of cyclin E-Cdk2. While most OVCAs express ER, anti- estrogens have been disappointing. Combined use of antiestrogens with drugs that block critical mitogenic signaling pathways may prevent or delay development of anti-estrogen resistance in ER+ OVCAs.The combined use of kinase inhibitors that block different constitutively activated pathways may also more effectively inhibit OVCA cell growth. Our HYPOTHESIS is that constitutive activation of Src and/or Ras/Raf/MEK promote cell cycle progression, rendering ER+ OVCA cells anti-estrogen resistant. We further postulate that Src and MEK inhibitors may cooperate together or with anti-estrogens to reverse resistance and decrease OVCA cell proliferation.
AIM 1 will test different Src inhibitor-drug combinations for anti-proliferative activity in an expanded series of ER positive OVCA cell lines and study the mechanisms of cell cycle arrest and apoptosis.
AIM 2 will compare drug effects on primary cultures derived directly from early and advanced stage OVCAs removed at debulking surgery.
AIM 3 will test the anti-tumor efficacy of combined Src inhibition with an antiestrogen or kinase inhibitor on xenografts using an innovative mouse OVCA renal capsule model. The pre-clinical data will help to identify novel drug combinations with the greatest anti-tumor efficacy that can be tested in future clinical trial. Although not mechanistically new, targeting ER and activated pathways is a novel therapeutic opportunity for recurrent OVCA patients who desperately need new therapies. Anti-estrogen treatment of early stage OVCA may prove to prevent or delay recurrence, which has never been explored.
Ovarian cancer is the most lethal gynecological malignancy and survival has only minimally improved over the last decade. The purpose of this grant is to discover novel molecular targeted drug combinations that work more effectively to arrest the growth of ovarian cancer cells and block ovarian cancer tumor progression. This work should identify novel more effective drug combinations that can be taken into the clinic in future phase I/II clinical trials for patients with ovarian cancer.