EFFECTS OF IN VIVO KNOCKDOWN OF A COLD-INDUCIBLE RNA-BINDING PROTEIN (CIRP) ON BREAST TUMORIGENESIS
Joey Ochoa, Daniel Lujan, Rebecca S. Hartley, Helen Hathaway.
The University of New Mexico, Albuquerque, NM.
RNA-binding proteins (RBPs) are essential to processes that involve RNAs, beginning from their transcription through to their degradation. In this study, we utilized the polyomavirus middle T antigen (PyMT) mouse model to evaluate the role of cold-inducible RBP (CIRP) in breast cancer. When PyMT is expressed in the mammary epithelium of mice, it causes aggressive tumorigenesis. CIRP has been shown to incite the translation of mRNAs encoding stress-induced proteins and is observed to have increased expression in breast cancer. We have shown that human CIRP overexpression in the PyMT mouse appears to inhibit breast tumorigenesis during early stages. Based on these results, the current study set out to evaluate the effects of CIRP knockdown on tumor development. We expect knockdown to allow greater progression of tumor growth, as well as a higher rate of metastasis. To address this hypothesis, CIRP will be knocked down using siRNA in a PyMT -mammary tumor- derived cell line. PyMT cells transiently transfected with siCIRP and siControl will be injected into the mammary fat pad of a wild-type mouse, and tumor growth will be assessed. CIRP knockdown in PyMT cells is being analyzed via RT-qPCR and western blotting to determine the effective timing for mammary fat pad injections. Tumor growth will be monitored every 3 days for 3 to 6 weeks. Final tumor burden and metastases will be assessed as will tumor progression, proliferation, and apoptosis. The results of this study will tell us if CIRP overexpression has the potential to protect against breast cancer.