Maintaining telomere length is an essential process for cancer cells to maintain replication. The re-activation or activation of telomerase in carcinogenesis has not been well understood. Recently Broad scientists discovered two recurrent mutations in the promoter of telomerase on chromosome 5: position 1,295,228 and position 1,295,250. These two mutations are cytosine to thymine changes coined “C228T” and “C250T.” The TERT promoter mutations C228T and C250T have subsequently been found in a number of cancers and are among the most common mutations in human cancer. While the mutations increase telomerase promoter activity, the effect of the TERT promoter mutations in non-cancer cell lines and the effect of co-occurring oncogenes on telomerase promoter activity have not previously been studied. We sought to determine if the C228T and C250T mutations would activate TERT promoter activity in non-cancer cell lines. In addition, we sought to measure the effect of oncogenic signaling on the TERT promoter by testing BRAF V600E, a known oncogenic mutation, and MEK-DD, a constitutively active form of MEK. To do so, we utilized a luciferase reporter assay using a portion of the TERT promoter to test the effect of the TERT promoter mutations in non-cancer cell lines and the effect of oncogenic signaling on TERT promoter activity. We hypothesized that oncogenic signaling would increase TERT promoter activity greater from the mutant TERT promoter than from the wild-type TERT promoter. We further hypothesized that in non-cancer cell lines, the wild-type TERT promoter would show no activity, while the mutant TERT promoter would show increased activity. Our results revealed that TERT promoter mutations increase TERT promoter activity in all cell lines and that oncogenic signaling increase TERT promoter activity by the same fold difference in wild type and mutants. Further research might reveal how TERT promoter mutations cooperate in cells and highlight potential areas for therapeutic intervention.
PROJECT: Investigating TERT promoter mutations in cancer
SRPG gave me the opportunity to work with an incredible group of scientists who exposed me to cutting- edge technology. My time spent at Broad ignited my passion for research and helped shape and identify my path for the future. I will treasure the friendships I have made and appreciate the support and encouragement I was given throughout the program.