We propose to test the hypothesis that when ligand binds chemokine receptors, a "dynamic chemosynapse" forms, comprised of receptor and adaptor proteins that serve to enable polarization, activation, amplification, and oscillation of small GTPases and kinases involved in organization of the actin cytoskeleton, and chemotaxis. Moreover, we propose that interference of chemokine receptor association with these adaptors will ablate CXCR2- and CXCR4-mediated chemotaxis, intravasation, extravasation, and metastasis. There are three specific aims. I) To test the hypothesis that a major role of AP-2 in mediating CXCR2/CXCR4 chemotaxis and metastasis is to orchestrate polarization and amplification of intracellular signals. We will separately interfere with AP-2 mediated receptor trafficking versus polarization of intracellular signals to distinguish the importance of these two functions of AP-2 in CXCR2/CXCR4 mediated chemotaxis and metastasis. 2) To characterize the role of IQGAP1 and VASP in linking the CXCR2 and CXCR4 chemosynapse to the actin cytoskeleton. We will characterize the interacting domains of IQGAP1 and VASP with CXCR2 and CXCR4 and determine the effects of altering these interactions on the functional responses to chemokine (including extravasation, intravasation, metastasis) of leukocytes, endothelial cells and breast cancer cells. 3) To test the hypothesis that Src-family kinase activation at the CXCR2 and CXCR4 `chemosynapse'drives chemotaxis that is Dock2 dependent and largely PI3K independent. We will determine the role of the Src-p130Cas-CrkL-Dock2 pathway in PI3K independent CXC2/CXCR4 chemotaxis. We will study these processes in dHL-60, dU937, HMEC-1 CXCR2 expressing cells and in the breast cancer cell lines naturally expressing CXCR4 (highly invasive MDA-MB-231, DU4475, BT-549 and non-invasive MCF-7, MDA-MB- 453 and MCF-10A cells). Microfluidic devices and real time intravital microscopy using 2 photon imaging will be used to track chemotaxis in vitro and intravasation/extravasation /metastasis in vivo, respectively. Characterization of the functional significance of this interaction between chemokine receptors and adaptor proteins that comprise the chemosynapse will unveil important new therapeutic targets for the treatment of malignancies. Characterization of the mechanism for PI3K independent chemotaxis will provide valuable information for design of therapies for sepsis, arthritis, and metastasis.
This study aims to test the hypothesis that receptors involved in regulating the motility of immune cells and tumor cells must interact with a number of proteins in the cytoplasm of the cell to stimulate proper organization of the cytoskeleton. In this study we propose to disrupt these protein/protein interactions to develop a new way of blocking tumor cell metastasis and chronic inflammation. We also will interrupt specific intracellular signals initiated by these protein/protein interactions to point the way to new targets for drug therapy for chronic inflammation and metastasis.
|Raman, Dayanidhi; Sai, Jiqing; Hawkins, Oriana et al. (2014) Adaptor protein2 (AP2) orchestrates CXCR2-mediated cell migration. Traffic 15:451-69|
|Ciombor, Kristen K; Feng, Yang; Benson 3rd, Al Bowen et al. (2014) Phase II trial of bortezomib plus doxorubicin in hepatocellular carcinoma (E6202): a trial of the Eastern Cooperative Oncology Group. Invest New Drugs 32:1017-27|
|Crowder, Spencer W; Horton, Linda W; Lee, Sue Hyun et al. (2013) Passage-dependent cancerous transformation of human mesenchymal stem cells under carcinogenic hypoxia. FASEB J 27:2788-98|
|Neel, Nicole F; Sai, Jiqing; Ham, Amy-Joan L et al. (2011) IQGAP1 is a novel CXCR2-interacting protein and essential component of the "chemosynapse". PLoS One 6:e23813|
|Rhodes, Lyndsay V; Short, Sarah P; Neel, Nicole F et al. (2011) Cytokine receptor CXCR4 mediates estrogen-independent tumorigenesis, metastasis, and resistance to endocrine therapy in human breast cancer. Cancer Res 71:603-13|
|Raman, Dayanidhi; Sobolik-Delmaire, Tammy; Richmond, Ann (2011) Chemokines in health and disease. Exp Cell Res 317:575-89|
|Richmond, Ann (2011) Chemokine research moves on. Exp Cell Res 317:553-5|
|Richmond, Ann; Yang, Jinming; Su, Yingjun (2009) The good and the bad of chemokines/chemokine receptors in melanoma. Pigment Cell Melanoma Res 22:175-86|
|Wang, Dingzhi; Dubois, Raymond N; Richmond, Ann (2009) The role of chemokines in intestinal inflammation and cancer. Curr Opin Pharmacol 9:688-96|
|Liu, Yuxin; Sai, Jiqing; Richmond, Ann et al. (2008) Microfluidic switching system for analyzing chemotaxis responses of wortmannin-inhibited HL-60 cells. Biomed Microdevices 10:499-507|
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