Faculty Publications

In the past 3 years, altered expression of the HEF1/CAS-L/NEDD9 scaffolding protein has emerged as contributing to cancer metastasis in multiple cancer types. However, whereas some studies have identified elevated NEDD9 expression as prometastatic, other work has suggested a negative role in tumor progression. We here show that the Nedd9-null genetic background significantly limits mammary tumor initiation in the MMTV-polyoma virus middle T genetic model. Action of NEDD9 is tumor cell intrinsic, with immune cell infiltration, stroma, and angiogenesis unaffected. The majority of the late-appearing mammary tumors of MMTV-polyoma virus middle T;Nedd9(-/-) mice are characterized by depressed activation of proteins including ART, Src, FAK, and extracellular signal-regulated kinase, emphasizing an important role of NEDD9 as a scaffolding protein for these prooncogenic proteins. Analysis of cells derived from primary Nedd9(+/+). and Nedd9(-/-) tumors showed persistently reduced FAK activation, attachment, and migration, consistent with a role for NEDD9 activation of FAK in promoting tumor aggressiveness. This study provides the first in vivo evidence of a role for NEDD9 in breast cancer progression and suggests that NEDD9 expression may provide a biomarker for tumor aggressiveness. [Cancer Res 2009;69(18):7198-206]

Ovarian cancer is one of the leading causes of death from gynecological cancers in the United States. Conventional therapies are unlikely to control advanced stage ovarian cancers, thus requiring innovative alternative therapies. In the current study, we characterized the therapeutic effect of tumor cell-based vaccines combined with the adjuvant, alpha-galactosylceramide (alpha-GalCer) using two different Mouse models. Our data suggests that treatment with alpha-GalCer led to an increase in the IFN-gamma serum levels in the presence or absence of irradiated mouse ovarian surface epithelial tumor cells (MOSEC). Furthermore, administration of irradiated MOSEC tumor cells with adjuvant alpha-GalCer generated significant protective and therapeutic antitumor effects against MOSEC tumors in vaccinated C57BL/6 mice. In addition, immune cells expressing CD4, CD8 or NK1.1 markers were found to be important for the protective antitumor effects generated by irradiated tumor cell-based vaccines combined with adjuvant alpha-GalCer. We also found that treatment of a spontaneous ovarian cancer murine model, the Mullerian inhibiting substance type II receptor T antigen (TgMISIIR-TAg) transgenic mice with ovarian tumor cell-based vaccines combined with adjuvant alpha-GalCer led to prolonged survival as well as increased numbers of tumor-specific CD8(+) T cells. Therefore, irradiated tumor cell-based vaccines in combination with alpha-GalCer are capable of breaking immune tolerance and generating significant antitumor effects in two different mouse tumor models. Our Study serves as a foundation for future clinical translation. (C) 2008 Elsevier Ltd. All rights reserved.

Our laboratory developed a transgenic mouse model of spontaneous epithelial ovarian cancer (EOC) in which tumors are initiated by expression of the early region of the Simian Virus 40 (SV40) under transcriptional control of the 5' upstream regulatory region of the Mullerian inhibiting substance type 11 receptor (MISIIR) gene. Female TgMISIIR-TAg-DR26 transgenic mice develop bilateral ovarian tumors with variable latency and survive an average of 152 days. In the absence of reliable methods for disease detection and evaluation of therapeutic response, preclinical studies of this transgenic mouse model of EOC would be limited to longitudinal experiments involving large numbers of animals with euthanasia as the endpoint. Therefore, a non-invasive method for detecting tumors, measuring tumor volume and calculating parameters relevant to the evaluation of therapeutic or preventive interventions (i.e., tumor growth rates, tumor initiation, tumor regression and the time for tumors to reach a given size) is required. We developed and optimized a non-invasive Magnetic Resonance Imaging (MRI) scanning protocol to obtain high resolution abdominal images that is well tolerated by mice. Superior contrast and contrast to noise ratio (CNR) was found with Gd-DTPA contrast enhanced T-1-weighted sequences. Image sets in both the axial and coronal orientations for redundant measurements of normal ovary and ovarian tumor volume can be acquired in approximately 20 minutes. Accuracy of MRI-based ovary and tumor volume determinations was verified by standard volume measurements at necropsy. Serial imaging studies were performed on 41 ovarian cancer bearing TgMISIIR-TAg-DR26 transgenic mice to quantitate tumor progression over time in this model. A chemotherapy study was conducted on TgMISIIR-TAg-DR26 transgenic mice using a standard combination therapy consisting of cisplatin and paclitaxel. Our results demonstrate that MRI is well tolerated and can be repeated in serial imaging studies, permitting quantitative analysis of tumor growth and progression and response to therapeutic interventions.

Mullerian Inhibiting Substance (MIS), a biological modifier that causes regression of Mullerian ducts in male embryos, is effective as a single agent in vitro and in vivo against human and mouse ovarian cancer cell lines expressing MIS type 11 receptor; however, little is known about how recombinant human MIS (rhMIS), now being scaled for preclinical trials, could be used in combination with cytotoxic or targeted chemotherapeutic agents. Mouse serous and endometrioid ovarian carcinoma cell lines were tested in vitro against rhMIS alone and with doxorubicin, paclitaxel, or cisplatin as agents in clinical use. Because MIS releases FK506 binding protein (FKBP12), which activates the mammalian target of rapamycin (mTOR) downstream of Akt, rhMIS and rapamycin combinations were tested. MIS increases p16 protein levels, and 5'-Aza2'-deoxycytidine (AzadC) induces p16 mRNA; therefore, they were used in combination in vitro and in vivo with a human ovarian cancer cell line. A paclitaxel-resistant human ovariain cancer cell line and its parental line both respond to rhMIS in vitro. Additivity, synergy, or competition was observed with MIS and rapamycin, AzadC, doxorubicin, cisplatin, and paclitaxel, suggesting that MIS in combination with selective targeted therapies might achieve greater activity against ovarian cancer than the use of each individual agent alone. These assays and statistical analyses could be useful in selecting rhMIS and chemotherapeutic agent combinations that enhance clinical efficacy and reduce toxicity.

The recent identification of "side population" (SP) cells in a number of unrelated human cancers and their normal tissue sources has renewed interest in the hypothesis that cancers may arise from somatic stem/progenitor cells. The high incidence of recurrence attributable to multidrug resistance and the multiple histologic phenotypes indicative of multipotency suggests a stem cell-like etiology of ovarian cancer. Here we identify and characterize SP cells from two distinct genetically engineered mouse ovarian cancer cell lines. Differential efflux of the DNA-binding dye Hoechst 33342 from these cell lines defined a human breast cancer-resistance protein 1-expressing, verapamil-sensitive SP of candidate cancer stem cells. In vivo, mouse SP cells formed measurable tumors sooner than non-SP (NSP) cells when equal numbers were injected into the dorsal fat pad of nude mice. The presence of Mullerian Inhibiting Substance (MIS) signaling pathway transduction molecules in both SP and NSP mouse cells led us to investigate the efficacy of MIS against these populations in comparison with traditional chemotherapies. MIS inhibited the proliferation of both SP and NSP cells, whereas the lipophilic chemotherapeutic agent doxorubicin more significantly inhibited the NSP cells. Finally, we identified breast cancer-resistance protein 1-expressing verapamil-sensitive SPs in three of four human ovarian cancer cell lines and four of six patient primary ascites cells. In the future, individualized therapy must incorporate analysis of the stem cell-like subpopulation of ovarian cancer cells when designing therapeutic strategies for ovarian cancer patients.