I) SYNTHESIS OF PLASMINOGEN ACTIVATOR (Pla) INHIBITORS IN YERSINIA PESTIS II) DEVELOPMENT OF SMALL MOLECULE INHIBITORS TO RESTORE NUCLEAR p27 AS A THERAPEUTIC METHOD FOR ENDOMETRIAL CANCER

Plasminogen activator (Pla) is an outer membrane protease produced by Yersinia Pestis (Y. pestis), a pathogenic bacterium that causes plague. Pla helps spread the bacteria from the primary infection site by activating a change from plasminogen to plasmin which degrades fibrin in human hemostatic system. Pla plays a very important role in the invasion of Y. Pestis as evidence in the increase of the median lethal dose (LD50) by a million-fold when mice were infected with bacteria in which the plasmid gene encoded Pla was inactivated. For this reason, Pla has become an interesting target in drug design and development. To develop an inhibitor for Pla, a tripeptide substrate DABCYL-Arg-Arg-Ile-EDANS has been synthesized. This fluorophore-containing substrate was used in a fluorogenic method to study Pla activity and inhibitory assay. Identification of a lead compound was conducted at Harvard Medical School. Derivatization of the lead gave analogs which will be tested for Pla inhibition to obtain IC50. Structure-activity relationship (SAR) study of the lead analogs can provide useful information to develop small molecule organic inhibitors for Pla and Y. pestis infection.

Endometrial carcinoma (EndoCa) is the most-common gynecologic malignancy and the fourth most common cancer in women in the United State. Along with kidney, prostate and breast cancer, EndoCa frequently loses (or mislocalizes) a tumor suppressor nuclear p27. p27 is a cyclin-dependent kinase inhibitor (CKI) that inactivate cyclin A- and cyclin E-CDK2 complexes in the nucleus to block cell cycle progression and inhibit cell growth. SCF E3 ligase (also called ubiquitin ligase) targets p27 for ubiquitination and further degradation. Interrupting the binding between the ligase and p27 could restore p27 activity specifically in the nucleus of the cells. High-throughput virtual screening (HTS) was performed by our collaborator at MD Anderson Institute for Advancing Clinical Studies to identify a lead compound, (E)-3-(3,4-dimethoxyphenyl)-2-(phenylsulfonyl)-N-(pyridin-3-ylmethyl)acrylamide. Analogs of the lead compound has been synthesized and sent for EndoCa inhibition testing. Hydrogenation of the double bond or removing the aromatic (benzylic) side chain of the amide section caused the loss of EndoCa inhibition activity. The results indicated that the double bond and the amide side chain are essential for inhibition. This information will be used to continue to develop a drug candidate, providing a plausible therapeutic method for EndoCa.