Specific peptide/toxin fusion protein for potential individualized therapy in chronic lymphocytic leukemia

Abstract

<p>B-cell chronic lymphocytic leukemia (Cll) is responsible for 22-30% of all reported leukemia cases in the Western world. There is no cure for this disease. Chemotherapy and immunotherapy are current treatments, but these therapies have adverse side-effects. The objective of this study was to develop a fusion protein carrying both a peptide which specifically binds to the B-cell receptor of Cll cells and the Pseudomonas aeruginosa toxin, TA. The peptide contained in the fusion protein would specifically target Cll cells and the toxin would kill the targeted cells. A genetic construct was made to express this fusion protein. In previous work, using a phage display library, we selected several phages carrying peptides which specifically bind to Cll cells from a patient. Based on the binding to these cells, the peptide llPART was chosen. The DNA sequence coding for this peptide was inserted into the pRSET-A plasmid carrying the DNA sequence for TA. DNA sequencing was used to verify that llPART and TA were cloned in the correct reading frame. E. coli was transformed with this plasmid. Using IPTGinduced expression, column purification techniques, and Western blot analysis, we confirmed that the 43 kD fusion protein was expressed in E. coli. Future studies will include use of this fusion protein to demonstrate specific Cll cell killing in vitro. Ultimately, this approach may provide an individualized treatment for Cll patients without the adverse effects caused by conventional therapies in use.</p><p>This presentation occurred at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 8, 2011</p>