Date on Master's Thesis/Doctoral Dissertation

12-2011

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Biochemistry and Molecular Biology

Committee Chair

Trent, John O.

Author's Keywords

CXCR4; metastasis; GPCR; intracellular; QSAR; molecular dynamics

Subject

Metastasis; Chemical inhibitors

Abstract

Metastasis is a complex process requiring directed migration of metastatic cells to favorable microenvironments. Increased CXCR4 expression has been implicated in more invasive, aggressive and metastatic tumor phenotypes and poor patient survival in twenty-three forms of cancer. CXCR4 has been linked to cancer metastasis and CXCR4 expression on the cell surface of tumor cells has been linked to increased migration and homing of neoplastic cells to sites where stromal cells express the chemokine CXCL 12 such as the lung and bone marrow. In this dissertation, we will utilize structure based drug design to identify inhibitors of CXCR4 targeting the extracellular surface of the receptor, as well as the intracellular interface between the GPCR and G-protein. Our screens of the extracellular surface identified one compound, ECLVS14, which inhibits chemotaxis with an IC50 value of 5 j..IM, and is highly selective for CXCR4 without significant cytotoxicity. Subsequent QSAR analysis of the structure of this inhibitor reveals the importance of the 1-[bis (phenyl methyl) amino] methyl moiety and the fact that electronegative modifications of the terminal benzene enhance activity. Subsequent Molecular dynamics simulations of the compound in complex with CXCR4 reveal that the compound induces significant modifications of the receptor structure. Our intracellular screens represent a novel screening strategy targeting the intracellular region of CXGR4 interacting with Gai, which identified ten compounds selectively inhibiting GXGR4 with IG50 values of 10 IJM or less. Three of the most active compounds from the extracellular and intracellular screens were tested in an in vivo anti-metastatic animal model, successfully demonstrating the anti-metastatic activity of these compounds. In total this work demonstrates that structure based drug design utilizing in silico analysis in combination with in vitro and in vivo testing can be utilized to develop novel lead compounds which can function as anti-metastatics.

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