Research Progress
In order to discuss the status of my research, let me first explain the objectives of my research.
In Dr. Seewaldt’s lab, one of the major focuses centers around finding biomarkers for breast cancer, whether they might lead to preventative treatments or else a diagnosis. A protein called PELP1 holds promise for providing us with such a biomarker. PELP1 is a coregulator protein of estrogen receptor (ER) and usually performs its regulation tasks strictly in the nucleus. However, it’s been recently discovered that certain cancer cell lines contain high amounts of cytoplasmic PELP1. Here’s where our research comes into play.
ER, which is typically found in very low levels in normal human mammary epithelial cells (HMECs), is frequently used to identify the pre-cancerous condition, atypia. Women with atypia are sometimes given the option of Tamoxifen treatment in order to prevent the progression to cancer. However, not all women respond to this drug, which has many unpleasant effects such as the increased risk of endometrial cancer. It is suspected that cytoplasmic PELP1 may be present in those women who are resistant to Tamoxifen, activating certain pathways that lead to cell proliferation and hormonal independence. Furthermore, the harder-to-detect ER-negative forms of atypia and breast cancer cannot be identified based on ER levels; the ER levels appear normal, yet the cells proceed to proliferate and become cancerous. If we discover cytoplasmic PELP1 in such atypical cells, perhaps the protein can be used as a more efficient detection technique.
The first step of our research is to confirm that the mutant PELP1-CYTO plays a part in activating the cancer-promoting AKT and MAPK pathways in ER+ cell lines. Similarly, we want to see if PELP1-CYTO can exist in and, if so, activates the same pathways. Next we’ll test if the protein can be transfected into and have the same effect in normal HMECs. This will tell us if such fluctuations in PELP1-CYTO are evident before cells actually become cancerous. With later investigation, we’ll take actual RPFNA (an aspiration technique for sampling cells from high risk women) samples and look for evidence of PELP1-CYTO and whether or not it correlates to resistance to Tamoxifen.
Currently, we’ve run one western blot to confirm the activation of AKT and MAPK pathways. However, results were not definitive. We’ve also performed immunofluorescence with an ER+ breast cancer cell line to experiment with the conditions needed to detect PELP1 most efficiently. All other efforts (digests, transfections, ligations, western blotting) have been aimed at preparing for future procedures. By the end of this program, we hope to have determined the effects of PELP1-CYTO in ER+ and ER- breast cancer cell lines as well as in normal HMECs in in vitro models.