Discipline: Biological Sciences
Subcategory: Cancer Research
Brianna Morris - Elizabeth City State University
Co-Author(s): Kristin Kwakwa and Julie Sterling Vanderbilt University, Nashville, TN
Tumor cells express Gli2, which increases secretion of osteolytic factors like Parathyroid hormone related protein (PTHrP). These factors stimulate osteoblasts to secrete RANKL, which activates osteoclast. This results in bone resorption, and the release of bone matrix growth factors like TGF- β. TGF-B increases tumor growth and Gli2 expression to promote a vicious cycle of bone destruction known as Tumor Induced Bone disease (TIBD). GANT58 a Gli antagonist is believed to inhibit the expression of Gli2, reducing osteolytic factors causing less tumors and bone destruction. Understanding PTHrP and Gli2 signaling in bone-derived tumors from patients can lead to better therapeutics and improve overall quality of life. We hypothesized that tumors residing in bone upregulate Gli2 and PTHrP and that inhibiting Gli2 will reduce tumor growth. First, we isolated cells from patient tumor samples that were surgically removed from sites of bone. By stimulating these tumor cells with transforming growth factor beta (TGF-β), an abundant protein found in bone, we will determine Gli2 and PTHrP mRNA and protein expression levels by quantitative real-time polymerase chain reaction (qPCR) and western blot respectively. Additionally, we will treat these cells with the Gli-antagonist GANT58 and evaluate growth and viability via trypan-blue staining. We believe that inhibition of Gli2 will reduce TGF-β-dependent expression of PTHrP in patient tumor cells as well as significantly reduce tumor growth in vitro. There was a significant increase in Gli2 and PTHrP expression in patient chondrosarcoma cells after stimulation with TGF- β, but no significant difference in total Gli2 protein expression after 24hr TGF- β stimulation. Future plans would be to Determine Nuclear Gli2 protein expression in patient bone residing tumors after TGF- β stimulation. Determine Gli2 and PTHrP expression in other human bone-derived tumors and determine if other Gli inhibitors affect patient tumor cell proliferation. In summary the inhibition of Gli2 by GANT58 reduces the expression of Gli2 concurrently reducing the secretion of PTHrP in patient tumors invitro.
Funder Acknowledgement(s): Vanderbilt University MARC- Elizabeth City State University
Faculty Advisor: Julie Sterling, firstname.lastname@example.org
Role: I had a key role in the whole process this project including running the experiments as well as analyzing the data.