Clifford M. Csizmar
Entering Class: 2012
Boise State University
Chemistry and Pre-Medical majors
University of Minnesota
Medicinal Chemistry Graduate Program
MSTP Student Governance:
- Student Admissions Committee, 2014-2016
- Student Advisory Committee, 2012-14
Honors and Awards:
- Ruth L. Kirschstein National Research Service Award for Predoctoral MD/PhD Fellows, National Cancer Institute (2016-2020)
- J. Jacob Kaplan Award, University of Minnesota Medical School (2019)
- Bighley Graduate Fellowship, University of Minnesota (2018)
- AIChE Oral Presentation Award, American Institute of Chemical Engineering (2017)
- IEM Poster Award in Cellular and Molecular Bioengineering, Institute for Engineering in Medicine (2017)
- University of Minnesota Dr. Warren J and Henrietta Holm Warwick Fellowship (2015-16)
Thesis Advisor: Carston Wagner, Ph.D.
The ability to direct cell-cell interactions has tremendous value in several therapeutic fields. While genetically-encoded artificial receptors have proven efficacious, their scope is limited by the genetic engineering that underlies the approach. To circumvent some of these limitations, our group has developed a non-genetic method to modify any cell surface with a targeted protein scaffold. First, we engineered a protein ligand based upon the human tenth type III fibronectin domain (Fn3) that binds to epithelial cell adhesion molecule (EpCAM), an overexpressed tumor antigen. Using yeast surface display, mammalian cell panning, and a novel titratable avidity-reduction selection technique, we evolved Fn3 clones exhibiting high affinity and robust selectivity for cellular EpCAM. We then incorporated these Fn3s into a multivalent chemically self-assembled nanoring (CSAN). EpCAM-targeted CSANs were anchored to cell membranes through the hydrophobic insertion of phospholipids into the lipid bilayer. The targeting elements were subsequently removed from the cell surface by disassembling the CSAN with the antibiotic, trimethoprim. Using this system, we successfully directed and reversed targeted intercellular interactions in vitro. Finally, the modular CSANs were used to study how avidity impacts the apparent affinity of a multivalent scaffold. By tuning the number of Fn3 domains on the CSAN, we quantitatively described how the apparent affinity changes as a function of ligand affinity, domain valency, and antigen expression density. These results informed the development of targeted CSAN capable of discriminating between EpCAM-expressing tumors in vivo. In conclusion, we developed a diverse toolkit for directing and studying cell-cell interactions. The CSAN platform is applicable to several therapeutic arenas and, by balancing affinity and avidity, may offer advantages over current cell-directing methods.
Csizmar CM, Petersburg J, Perry TJ, Rozumalski L, Hackel BJ, Wagner CR. Multivalent Ligand Binding to Cell Membrane Antigens: Defining the Interplay of Affinity, Valency, and Expression Density. J Am Chem Soc. 2019 Jan 9;141(1):251-261.
Csizmar CM, Petersburg JR, Wagner CR. Programming Cell-Cell Interactions through Non-genetic Membrane Engineering. Cell Chem Biol. 2018 Aug 16;25(8):931-940. PMCID: PMC6470397
Petersburg JR, Shen J, Csizmar CM, Murphy KA, Spanier J, Gabrielse K, Griffith TS, Fife B, Wagner CR. Eradication of Established Tumors by Chemically Self-Assembled Nanoring Labeled T Cells. ACS Nano. 2018 Jul 24;12(7):6563-6576. PMCID: PMC6506352
West HT, Csizmar CM, Wagner CR. Tunable Supramolecular Assemblies from Amphiphilic Nucleoside Phosphoramidate Nanofibers by Enzyme Activation. Biomacromolecules. 2018 Jul 9;19(7):2650-2656. PMCID: PMC6628205
Csizmar CM, Petersburg JR, Hendricks A, Stern LA, Hackel BJ, Wagner CR. Engineering Reversible Cell-Cell Interactions with Lipid Anchored Prosthetic Receptors. Bioconjug Chem. 2018 Apr 18;29(4):1291-1301. PMCID: PMC5937253
Stern LA, Csizmar CM, Woldring DR, Wagner CR, Hackel BJ. Titratable Avidity Reduction Enhances Affinity Discrimination in Mammalian Cellular Selections of Yeast-Displayed Ligands. ACS Comb Sci. 2017 May 8;19(5):315-323. PMCID: PMC5521271
Csizmar CM, Kim DH, Sachs Z. The role of the proteasome in AML. Blood Cancer J. 2016 Dec 2;6(12):e503. doi: 10.1038/bcj.2016.112. Review. PMCID: PMC522314
For work prior to the UMN MSTP
Csizmar CM, Daniels JP, Davis LE, Hoovis TP, Hammond KA, McDougal OM, Warner DL. Modeling SN2 and E2 reaction pathways and other computational exercises in the undergraduate organic chemistry laboratory. J Chem Educ. 2013 Sept;90(9):1235-1238.
Csizmar CM, Force DA, Warner DL. Examination of bond properties through infrared spectroscopy and molecular modeling in the general chemistry laboratory. J Chem Educ. 2012 Feb;89(3):379-382.
Csizmar CM, Force DA, Warner DL. Implementation of gas chromatography and microscale distillation into the general chemistry laboratory curriculum as vehicles for examining intermolecular forces. J Chem Educ. 2011 July; 88 (7):966-969.