Presenters: Dresdan Quackenbush ; Jordan Olsen
Authors: Jordan Olsen, Dresdan Quackenbush, Saxon Stringham, Richard Warner
Faculty Advisor: Richard Warner
Institution: Dixie State University
Purpose: To determine protein interactions with B7-H3 that participate in immune signaling and their potential as targets for immunotherapy targeting. Context: In cancer, there is a failure of the immune system to recognize and kill cancer cells. Recently there has been great interest in developing immune therapies to reinitiate this anti-tumor response. Proteins in the B7 family stimulate or inhibit immunoregulatory signaling. In this family, B7-H3 has recently been confirmed to show immune inhibitory functions in mouse models of carcinomas and has potential for immunotherapy targeting and anti-tumor immune reactivation. To identify B7-H3 associated proteins, immunoprecipitations were previously performed in conjunction with mass spectrometry. The top candidate identified from these experiments was midkine (MDK), a growth factor known to stimulate cells including lymphocyte proliferation. The interaction of B7-H3 and MDK was determined in the absence of protein cross-linking and withstood cell lysis with a mild detergent (1% Triton-X 100 buffer). Methods: Our goal in this project is to develop a protein complementation assay (PCA) to confirm the direct interaction of these proteins. To do this we can fuse complementary fragments of a reporter protein,Gaussialuciferase enzyme, to the proteins of interest, B7-H3 and MDK. We designed PCA to include B7-H3 and MDK complementary vectors, and we made primers to clone our genes into corresponding restriction sites of PCA vectors in the correct reading frame. Currently, we are carrying out the molecular cloning of both genes. Conclusion: We hope development of this assay system will contribute to our knowledge of B7-H3 and potential novel therapeutic possibilities for future patients using immunotherapy toward B7-H3 or MDK.