Dissecting the Molecular and Biological Contributions of the SMARCA4 Tumor Suppressor to Formation of Small Cell Carcinoma of the Ovary, Hypercalcemic Type (SCCOHT)
Abstract
Small Cell Carcinoma of the Ovary, Hypercalcemic Type (SCCOHT) is a rare, but extremely aggressive form of ovarian cancer that afflicts young women. Most SCCOHT tumors have inactivating mutations in the SMARCA4 gene, which regulates expression of other genes regulating cell growth. Although SCCOHT is a rare disease, SMARCA4 mutations are found in many different types of cancers, including breast, melanoma, kidney, and uterine cancers. Thus, understanding how mutations in SMARCA4 contribute to tumorigenesis in SCCOHT is applicable to many different cancers. In a rare opportunity, we have access to tissues from a patient (P590) carrying a single copy of a novel SMARCA4 mutation who underwent preventive ovary removal due to a family history of SCCOHT. Using ovarian epithelial cells (OSEs) isolated from P590’s ovaries, we have observed that her cells continue to grow after several cell doublings, while cells from an otherwise normal patient stop growing and die. P590’s cells can form miniature tumor-like masses in a dish or in suspension culture. This suggests that her cells are predisposed to form tumors. This gives us a unique opportunity to observe how P590’s cells change as they transition from an otherwise normal cell and acquire tumor like properties. For our proposal, we will use several cell biology techniques to confirm that P590’s cells behave like cancer cells over time (Aim 1). A definitive test will be to inject her cells into mice to see whether they can form tumors. SMARCA4 regulates cellular DNA packaging and controls the access of other proteins to DNA, thereby regulating gene expression. In Aim 2, we will examine changes in DNA packaging and the resulting changes in gene expression that occur as P590’s cells grow and transform in culture. These studies may identify new gene targets for the development of improved therapeutic approaches targeting SMARCA4 mutations. Using normal ovarian cells, we will use CRISPR/Cas gene editing technology to introduce specific mutations in SMARCA4 and see whether we can induce cancer-like behavior in normal cells (Aim 3). Combined, these experiments will test our preliminary observations and provide a research tool for drug screening and tumor studies in SCCOHT and other cancers that can become more aggressive and difficult to treat with SMARCA4 mutations (like uterine, breast and skin cancers). Which individuals will it help and how will it help them? SCCOHT is a disease that primarily afflicts young women, with an overall survival rate of 10%. This abysmal survival rate is likely due to the overall rarity of the disease, making it difficult to acquire and study early-stage tumor tissue or pre-cancerous cells. Moreover, because of the recent discoveries linking SMARCA4 mutations to SCCOHT, more and more women and girls are being screened for SMARCA4 mutation, but the field does not have adequate knowledge to link the specific SMARCA4 mutations to SCCOHT or other tumor types. If our proposal is successful, we may be able to use cell culture techniques to test the role of specific SMARCA4 mutations on SCCOHT formation. This would then give us a way of screening for common weak points in these cells that make them more or less susceptible to specific chemotherapeutic approaches. It may also help us identify new markers for characterizing early-stage SCCOHT. What are the potential clinical applications, benefits, and risks? The recent discovery of SMARCA4 mutations as a risk factor for SCCOHT has led to clinical referrals to the Co-PI (Dr. Pejovic) for aggressive clinical surveillance. In one specific case, the family (a mother and her young daughter) without a history of SCCOHT were identified as carriers of a novel mutation in SMARCA4 (c.3951+2T>C). Genetic counselors have recommended frequent radiological analyses, which is an expensive and stressful approach for both patients. If our hypothesis is correct, we can introduce their specific mutation
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 05, 2021
- Source ID
- W81XWH2110512
Entities
People
- Adam J. Krieg
Organizations
- Oregon Health & Science University
- United States Army