Abstract PO-132: Upregulated LYL1 promotes epithelial ovarian cancer (EOC) cell growth and metastasis

Approximately 90% of ovarian cancer (OC) is Epithelial ovarian Cancer (EOC) subtype and claims ~15,000 lives in the United States annually, making it the deadliest reproductive cancer in women. There are few treatment options for EOC, amongst them include surgical resection of tumors or debulking, and chemotherapy alone or combination. In general, the survival rate of patients with EOC is about 48% and this has not changed in last few decades. According to recent reports from American Cancer Society and SEER, racial disparity in ovarian cancer not only exists for African American (AA) patients, but is worsening over the past few years. African American (AA) patients presents with more advanced disease and develop chemoresistance frequently, and as such, they experience worse survival. Thus identifying the cause of this discrepancy, or more importantly, describing which AA patients are at the highest risk of therapeutic relapse would alter our current treatment strategies and improve overall disease free survival rate. Therefore, the central focus of this proposal is to delineate the molecular and genetic mechanisms contributing to racial disparity of AA patients. Therefore, the overall objective of our studies are to identify the etiology of racial disparity in ovarian cancer and define the molecular networks that contribute this discrepancy in outcomes. Lymphoblastic Leukemia-Derived Sequence 1 (LYL1) is a polypeptide that harbors basic helix-loop-helix transcription factor, a DNA binding motif and dysregulated in many cancers including EOC. Analysis of TCGA data for EOC revealed that LYL1 gene amplification in about 12% patients and associated with poor prognosis. Interestingly, further analysis of LYL1 copy number alteration in different ethnicities disclosed LYL1 amplification in about 36% of the African American (AA) EOC patients. Importantly, EOC patients with low LYL1 (n=1640) expression has better survival probability compared to patients with overexpressed LYL1 (n=202). This discrepancy in survival probability is much more prominent in AA EOC patients. As this is an intriguing observation, we evaluated the levels of LYL1 expression in different EOC cell lines in comparison with fallopian tube epithelial cells. Our data shows, upregulation of LYL1 in most of the EOC cell lines compared to normal fallopian tube epithelial cells. To examine the upregulated LYL1 in EOC cell lines, we performed siRNA mediated downregulation, and evaluated their clonogenic, migration invasion potential. Consistent with the TCGA data, knocking down LYL1 in EOC cells significantly attenuated their clongenic, migration and invasion potential. Furthermore, ectopic overexpression of LYL1 in EOC cells that shows deep deletion of the gene, exhibited increased clonogenicity, invasion and migration. Collectively, our studies indicate an important role for LYL1 in EOC tumor progression and metastatic phenotypes, and could be a biomarker for disparities in EOC outcomes. Citation Format: Damieanus Ochola, Shirisha Jonnalagadda, Swetha Peddibhotla, Tasmin Omy, Mark Reedy, Palle Komaraiah. Upregulated LYL1 promotes epithelial ovarian cancer (EOC) cell growth and metastasis [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-132.