University of New Hampshire
Mentor: Dr. David Townson
Examining the Tumorgenic Ability of K+/K- HeLa Cells in vitro
Cervical cancer is the second-leading cause of cancer-related death among women. Infection of the cervix by the human papillomavirus (HPV) often leads to cervical cancer. However, the cellular mechanisms by which HPV-infected cervical cells proliferate, migrate, and evade immune attack during metastasis are relatively unknown. We have determined that certain cervical cancer cells, known as HeLa cells, not only contain HPV but also have two distinct characteristics: some cells readily express keratin filaments (K+ cells), while others lack these filaments (K- cells). The keratins are a family of structural proteins that carry out a variety of functions within cells, with the most prominent being protection of the cells from mechanical and non-mechanical stresses (e.g., immune-mediated attack). The extent to which keratins are detectable in the blood is also diagnostic marker of cervical cancer. The question posed in this study is: What is the rate of proliferation and motility between K+ and K- HeLa cells, and is the K+ cell more aggressive in its growth? To begin to address this question, a preliminary experiment (repeated three times) was conducted using relatively pure populations of K+ and K- HeLa cells to determine the proliferation rate of the two cell types. Using cell growth tubes incubated for seven days, and cell counts quantified with a hemacytometer at 24-hour intervals, the multiplication rate (Mean ± SEM) of K+ vs. K- cells was calculated as 0.05 ± vs. 0.04 ± doublings per day, and the generation time (Mean ± SEM) as 21 ± vs. 25 ± hours, respectively. This indicated that the K+ cells double at a slightly higher rate, resulting in a shorter generation interval. A second experiment is currently underway to confirm these findings over a longer period, using higher initial cell concentrations. Future plans are to conduct an assessment of cell motility and aggressiveness using wound-healing and cell migration assays, respectively. The results are anticipated to provide a better understanding of how keratin filaments influence HeLa cell physiology beyond simply being a diagnostic measure of cervical cancer.