UC San Diego

Luteinizing Hormone Receptors (LHR) are highly expressed in many cases of ovarian cancer. The only normal tissues that express high levels of LHR are the ovaries and fallopian tubes which are normally removed as part of the initial surgical management of the disease. One approach to selectively killing tumor cells is to use carriers that can transport a cytotoxic molecule selectively to the tumor. I used a modified form of hCG (named YCG) as a carrier and the cytotoxin monomethyl auristatin E (MMAE) as the cytotoxin. A vector capable of expressing a protein containing the Fc domain and the carrier protein was constructed. The Fc-YCG-tags-His protein was successfully produced in transiently transfected ExpiCHO cells and purified by protein A resin. MMAE was conjugated to the YCG using the sortase reaction, and the drug (Fc-YCG-MMAE) was analyzed by gel electrophoresis, HPLC analysis, Western blot, and cytotoxicity assay. The cytotoxicity analysis of Fc-YCG-MMAE produced well-defined concentration-survival curves and cells transiently transfected with the LHR vector were ~4-fold more sensitive than the cells transfected with the control cells. This work demonstrated the feasibility of using a naturally occurring hormone as a targeting moiety for a potent cytotoxic agent and provided the foundation for the further development of novel cancer therapeutic.