Each year, MOCA funds research which advances the treatments and cure for ovarian cancer. All of the money dedicated to research stays in the state of Minnesota. In 2006, we are proud to announce that through our combined hard work and dedication to this cause, MOCA funded almost $316,605 to four ovarian cancer research projects. After reviewing 15 proposals submitted to MOCA, our grant review panel, composed of three national experts in ovarian cancer research and four consumer representatives, made the funding recommendations which were accepted by the MOCA Board of Directors. A summary of this research is listed below.

Summary Abstracts of 2006 Research

“Investigation of the Contribution of the Fanconi Anemia Pathway to Ovarian Cancer Treatment” submitted by Peiwen Fei, M.D., Ph.D., Department of Laboratory Medicine & Pathology, Mayo Clinic. $74,430.

Ovarian cancer is the leading cause of death in women with gynecological tumors. Studies have been conducted on ovarian cancer treatment for over three decades, but no significant improvements have been made in the absolute cure rate of advanced-stage ovarian cancer. DNA-crosslinking agents, including Cisplatin/Carboplatin, have been extensively used in the chemotherapy for ovarian cancer. However, ovarian cancer patients have been found to develop resistance to these agents. The mechanisms underlying this resistance are not fully understood. It is known that the Fanconi Anemia (FA) pathway has been involved in the repair processes of DNA damage caused especially by these agents. This pathway is constituted by a group of FA proteins, and monoubiquitinated FANCD2 is a measure of this pathway activation. My preliminary studies and those of others showed that the impaired FA pathway conferred the cell sensitivity to DNA crosslinking agents. This let us hypothesize that the sensitivity/resistance of ovarian tumor to Cisplatin/Carboplatin may be also relevant to the integrity of FA pathway. To test this hypothesis, we will pursue studies of two aspects:

Aim 1: To investigate the platinum sensitivity of ovarian cancer cell xenografts with different status of FA pathway in mice.
Aim 2: To reveal the potential association between the status of FA pathyway and outcomes of ovarian cancer patients treated with Cisplatin/Carboplatin.

The experiments in aim 1 will be conducted mainly through using a bioluminescent system to monitor the growth of ovarian cancer cell xenografts in mice treated with Cisplatin. The xenografts will be established from the ovarian cancer cells with an intact FA pathway and an impaired FA pathway, respectively. Thus the different outcomes of treatment directly result from the different status of the FA pathway. The experiments in aim 2 will be performed through detecting the status of FA pathway in ovarian cancer specimens available in the Mayo Clinic Ovarian Cancer Resources. This will give an indicative association between the FA pathway and the outcomes of chemo-resistance in ovarian cancer patients.

The results of this proposal will provide first-hand information regarding the implications of FA pathway in ovarian cancer treatment. The expected results will be in favor of manipulating the status of FA pathway during chemotherapy for increasing tumor sensitivity, and will suggest utilizing other chemotherapeutic agents if a given ovarian tumor harbors an intact FA pathway. Both will presumably be useful tools to improve the survival rate of patients with ovarian cancer.

“Complementary Proteomic Techniques to Identify Ovarian Cancer Biomarkers” Submitted by Amy Skubitz, Ph.D., Department of Laboratory Medicine & Pathology, University of Minnesota.I $93,670.

The studies outlined in this proposal are focused on improving the detection of ovarian cancer by identifying novel biomarkers for ovarian cancer. Early detection of ovarian cancer results in improved survival rates for patients. Since current screening techniques are neither adequately sensitive nor specific, ovarian cancer is usually not detected in ints early stages. In addition, novel biomarkers are needed for detection of recurrence of ovarian cancer.

The field of proteomics encompasses the next generation of discovery tools for those seeking biomarkers of disease. Advances in technology and state-of-the-art instrumentation have combined the highly sensitive instrumentation of mass spectrometry with conventional gel electrophoresis and liquid chromatography.

A major roadblock in the discovery of protein biomarkers that are disease-specific are the abundant proteins of serum. Just 12 proteins make up approximately 90% of the serum. Thus, unique proteins that may be specifically found in the sera of women with ovarian cancer are masked by thse highly abundant proteins.

To overcome this problem, we propose first to remove these 12 highly abundant proteins from all sera samples, and then to analyze the samples by three different techniques in order to identify ovarian cancer-specific proteins. The three mass spectrometry-based techniques that we propose to use are highly complementary, such that the deficits of one technique are overcome by the strengths of the others. Furthermore, the data generated by the three techniques will permit better adjustment of the sample preparation and analysis protocols to optimize the ability to discover specific protein biomarkers in the sera of patients with ovarian cancer.

“Modeling Ovarian Cancer TCEAL Deficient Mice” Submitted by Jeremy Chien, Ph.D., Department of Experimental Pathology, Mayo Clinic. $69,605

Ovarian cancer etiology is not well understood because of the complexity of genetic alterations and the specific roles these alterations play in ovarian cancer initiation, progression and the development of chemoresistant disease. A better understanding of the earliest genetic changes that lead to a transformed phenotype may contribute to deciphering the underlying etiology of ovarian cancer. In contrast to other tumor types, efforts to model human ovarian cancer were delayed due to a lack of understanding of the disease process. However, over the past five years a few genetically engineered mouse models of ovarian cancer have been generated. While each of these models has unique strengths, relevance of each model to human ovarian cancer is limited by the prevalence of these genetic alterations in ovarian cancer. The utility of some of these models is further limited by low frequency of tumor induction. These results suggest that additional genetic alterations are necessary for induction of ovarian cancer.

Recently, we have identified a novel tumor suppressor, TCEAL7, to be down-regulated in 90% of human ovarian cancer cell lines and human primary ovarian cancer. TCEAL7 is down-regulated in ovarian cancer of different histology, indicating that it may represent a common genetic alteration in the etiology of ovarian cancer. Specifically, down-regulation of TCEAL7 in the background of compromised p53 and Rb function was sufficient to transform nonmalignant human surface epithelial cells. This is the very first report of a novel tumor suppressor gene with the ability to transform nonmalignant ovarian surface epithelial cells in the absence of activated Ras and small t antigen. More importantly, since the expression of TCEAL7 is lost in 90% of ovarian cancer cell lines and primary ovarian tumors, we surmise that the loss of TCEAL7 expression could represent one of the earliest genetic alterations associated with the etiology of ovarian cancer.

Therefore, we hypothesize that TCEAL7 down-regulation is an initiating event in the transformation of normal ovarian surface epithelium concurrent with p53 inactivation. To test the role of TCEAL7 in ovarian cancer, we propose the following:
1. To generate a TCEAL7 knockout muse model and investigate ovarian surface epithelium homeostasis.
2. To investigate the cooperation between loss of function of TCEAL7 and p53 in the development of an ovarian cancer model.

“Defining the Mechanism of Drug Resistance in Ovarian Cancer” Submitted by Viji Shridhar, Ph.D., Cancer Center & Division of Experimental Pathology, Mayo Clinic. $77,900.

Most women with advanced ovarian cancer ultimately relapse and die of disease progression despite an initial response to first line platinum-paclitaxel; and only a small minority (~20%) is cured with the standard combination. If those women who will drive little benefit from standard platinum-paclitaxel could be identified prior to therapy, namely those with early recurrence, then early intervention with alternative approaches, including novel agents targeted to molecular pathways (that are aberrantly activated), may lead to tailored therapies in patients with ovarian cancer.

In this context, a recent report from Tweari et all who analyzed 6990 malignant tissues from primary and metastatic sites using the extreme drug resistance assay suggested that the molecular alterations that lead to drug resistance may occur early in the carcinogenic process and persist in the metastatic sites. Therefore, the identification of genetic changes in the tumor at the time of diagnosis after the debulking surgery may help clinicians in choosing a targeted therapy. Toward this goal, we utilized cDNA microassay technology containing 30,721 transcripts to profile gene expression patterns from 79 ovarian cancer specimens to identify a predictive model for those tumors with early recurrence. These analyses resulted in the identification of 14-gene model that accurately predicted early or late recurrence in 86% of patients in the test set (p<0.05). Interestingly, the list did not include genes known to be involved in drug resistance such as ATP binding cassette transporters, metallothionine or DNA repair components. Instead, our analysis identified a unique set of nuclear factors that are implicated in survival and programmed cell death.

The anti-proliferative effects of cisplatin and other genotoxic chemotherapeutics are thought to be exerted by engagement of apoptotic regulators. The dysregulation of these pathways in cancer cells not only confers and intrinsic survival advantage, but also renders cells chemoresistant. In ovarian cancer, drug tailored regimens are hindered by a lack of understanding as to exactly how drug treatments engage apoptotic and non-apoptotic regulators in cell-death pathways.

The transcription factor ND-kB is a key regulator of a survival pathway in cancer cells and play a critical role in ongogenesis and tumor progression. Furthermore inhibition of ND-kB augments sensitivity to cancer therapies in various types of cancer. Mabuchi et al. recently linked NF-kB inhibition to an increase in cisplatin efficacy in in vitro and in vivo ovarian cancer models. Since NF-kB signaling is a focus of intense research in novel drug discovery, a better understanding of how NF-kB signaling is regulated would provide novel therapeutic targets to overcome drug resistance. In one of the genes identified, PLJ20241 showed higher expression in early recurrence in our study, and is a nuclear factor-B (NF-kB)-activating protein that was also identified as a gene that activates NF-kB and MAPK in a large-scale experimental study.

To further investigate the role of putative NF-kB activator in ovarian cancer chemoresistance we have generated expression constructs of FLJ20241 in both prokaryotic (PGEX) and Eukaryotic expression (pcDNA3.1) vectors. Also using the purified PLJ20241-GST fusion protein we have generated polyclonal antibodies to both the N- and C-terminal region of this protein. Using these antibodies, we have shown higher levels of FLH20231 expression in cisplatin resistant cell lines A2780/cp70 and A2780/C200 compared to the parental !2780 cisplatin sensitive line.

Based on the above results, we hypothesize that FLJ20241 could b used as a marker to predict chemoresistant disease. To further evaluate the biological effects of FLJ20241, we propose the following:
1. To evaluate the effect of FLJ20241 expression on ovarian cancer resistance in vitro.
2. To correlate the stable expression of FLJ20241 to chemoresponse, disease free survival and overall survival in patient samples.
3. To identify interacting proteins and initially map the pathways mediated by FLJ20241.