Simultaneous Ligand Directed Cytotoxic Toxin and Endosome Disruptor Delivery to Ablate Prostate Cancer
Abstract
We proposed that the efficacy of G-protein coupled receptor (GPCR) ligand directed toxins is limited by sequestration and degradation in the endosome following endocytosis. We proposed that a GPCR ligand-endosome disruptor conjugate would enhance the efficacy of a GPCR ligand-toxin conjugate. We engineered E. Coli that synthesize listeriolysin O (LLO), an endosome disruptor, and developed a fast protein liquid chromatography method to purify this LLO. We used solid state protein chemistry to synthesize gastrin release peptide (GRP) and gonadotropin releasing hormone (GnRH) then created conjugates with the ribosome inactivating protein toxin, Saporin, and the endosome disruptor, LLO. Both GRP-Saporin and GnRH-Saporin were effective in ablating two immortalized prostate cancer cell lines (DU145 and PC3 cells) in vitro, with GRP-Saporin effective at lower concentrations. The efficacy of both GRP-Saporin and GnRH-Saporin were enhanced by simultaneous treatment with LLO conjugates respectively. We are currently conducting research to complete in vivo mouse studies aimed at understanding the efficacy of these conjugates in a tumor implant model. These in vivo studies will include a GPCR ligand-doxorubicin conjugate to test the efficacy of endosome disruptors in preventing loss of efficacy due to endosomal sequestration. By including doxorubicin conjugates our findings may be more quickly applied to improve a compound in phase 3 clinical trials.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2019
- Accession Number
- AD1094808
Entities
People
- Benjamin J. Renquist
- Josef Vagner
- Kyle Kentch
- Ramesh Selvaraj
- Renata Patek
- Revathi Shanmugasundaram
Organizations
- University of Arizona
- University of Georgia