Ph.D. University of Manitoba, 1994
Office: WO 4262B
Phone No: 419.530.1966
Cancer is the second leading cause of death in the United States and claims
half a million people each year. We are focused on uncovering the mechanisms responsible
for cancer formation in particular the errors that occur during mitotic cell division.
Our research asks questions regarding two key mitotic proteins, Borealin and Sororin,
revealing how they coordinate chromosome movement and separation during mitosis. We
are also involved in a collaborative project in which we have developed a new class
of molecules that we call CETZOLEs. These molecules kill certain types of cancer cells
by inducing catastrophic accumulation of reactive oxygen species and we are in the
process of evaluating the potential of these compounds as novel chemotherapeutic agents.
In a genome-wide screen for novel mitotic genes we identified two that were poorly characterized: Borealin and Sororin. Sororin is now known to regulate the cohesin complex. Cohesin holds replicated chromosomes (also known as chromatids) together until anaphase when the chromatids are segregated to opposite poles of the cell. Cohesin was known to show multiple chromosome binding modes: dynamic during G1, stable during G2 and again dynamic during prophase along chromosome arms. Our studies uncovered part of the mechanism allowing removal of cohesin from chromosome arms during prophase. We observed that Sororin was phosphorylated by the mitotic protein kinase Cdk1 and that this modification released Sororin from chromatin and the cohesin complex. We mapped the sites of phosphorylation and found that disrupting Sororin phosphorylation blocked the separation of chromatids by altering cohesin. Studies from other labs indicated that defects we observed could alter chromosome segregation leading to cells with losses a gains of chromosomes, one of the driving forces behind cancer. Our work provided part of the mechanism responsible for this removal pathway.
Borealin is a key component of the chromosomal passenger complex (CPC) that detects and destabilizes inappropriate attachments of chromosomes to the mitotic spindle, the structure physically drags chromosomes to opposite ends of the cell. We mapped a key site of Cdk1 phosphorylation at S219, which was crucial for full CPC function on chromosomes. A previous study identified a dimerization domain at the C-terminus of Borealin. Our follow up studies indicated that this region was critical for Borealin and the CPC to stably interact with chromosomes. For these studies, we used genetic engineering to replace the dimerization domain of Borealin with the small protein FKBP. FKBP itself dimerizes when cells are exposed to a small compound. In this way, we can induce Borealin dimerization at the time of our choosing simply by adding the dimerization compound. We also used a sensitive microscopy technique called FRAP that allows us to observe diffusion of our engineered proteins in living cells. These techniques allowed us to determine the role of Borealin dimerization in chromosome binding and chromosome separation during mitosis.
In a more recent collaborative project with Dr. Tillekeratne in Medicinal and Biological Chemistry at UT, we have analyzed the cellular effects of novel open-chain epothilone analogues we have developed called CETZOLEs. These compounds block import of the amino acid cysteine into cancer cells essentially blocking their ability to remove toxic reactive oxygen species. Within 12 hours, the cells die by disruption of membrane structures. Importantly, these compounds are very toxic to a types of cells called mesenchymal cells. Mesenchymal cells are responsible for many of the pathological consequences of human cancers and many research groups are trying to find ways to kill mesenchymal cancer cells. Our ongoing work will test the clinical potential of these compounds in the treatment of cancer.
Current Laboratory Grants
deArce-Koch Memorial Foundation Biomedical Program Taylor (Co-PI) 05/14-12/16
Preclinical studies of a new class of anticancer agents for lung cancer.
The goal of this project is to investigate a new class of compounds developed in collaboration with another PI in the Department of Medicinal and Biological Chemistry at the UT. My role as a co- PI is to supervise biological studies including analysis of effects in cell culture and animal models.
Fedorka, SR, So, K, Gad, I, Shah, R, Junk, D, Rogers, T, Kholodovych, V, Jackson, MW, Taylor, WR and Tillekeratne, LMV. (2016). Small-Molecule Ferroptotic Agents with Potential to Selectively Target Cancer Stem Cells. In preparation
Rajanayake, KK, Taylor, WR, and Dragan Isailovic. (2016). The comparison of glycosphingolipids isolated from an epithelial ovarian cancer cell line and a nontumorigenic epithelial ovarian cell line using MALDI-MS and MALDI-MS/MS. Carbohydrate Research. In press
Bekier ME and Taylor WR. (2016). Traveling through mitosis with the chromosomal passenger complex. In Bradshaw and Stahl (eds). Encyclopedia of Cell Biology. Burlington, MA: Elsevier (BOOK CHAPTER).
Ji, W, Arnst, C, Tipton, AR, Bekier, ME, Taylor, WR, Yen, TJ, Liu,ST. (2016). OTSSP167 abrogates mitotic checkpoint through inhibiting multiple mitotic kinases. PLoS One. 2016 Apr 15;11(4): e0153518. doi: 10.1371/journal.pone.0153518.
Borton, ME, Rashid, MS, Dreier, MR, and Taylor, WR. (2015). Multiple Levels of Regulation of Sororin by Cdk1 and Aurora B. J Cell Biochem. 2015 Jul 14. doi: 10.1002/jcb.25277.
Bekier, ME, Mazur, T, Rashid, MS and Taylor, WR. (2015). Borealin dimerization mediates optimal CPC checkpoint function by enhancing localization to centromeres and kinetochores. Nat. Commun. 6:6775 doi: 10.1038/ncomms7775.
Tillekeratne, L. M. V., Fedorka, S., and Taylor, W. Highly selective anticancer agents small cell lung cancer and other forms of cancer. International patent application no. PCT/US2014/012359 filed on January 21, 2014. (PATENT)
Tipton AR, Ji W, Sturt-Gillespie B, Bekier ME 2nd, Wang K, Taylor WR, Liu ST. Monopolar spindle 1 (MPS1) kinase promotes production of closed MAD2 (C-MAD2) conformer and assembly of the mitotic checkpoint complex. J Biol Chem. 2013 Dec 6;288(49):35149-58. doi: 10.1074/jbc.M113.522375. Epub 2013 Oct 22.
Date, D, Dreier, MR, Borton, MT, Bekier, ME and Taylor, WR. (2012). Effects of Phosphatase and Proteasome Inhibitors on Borealin Phosphorylation and Degradation. Journal of Biochemistry, in press.
Dreier MR, Bekier, ME and Taylor, WR. (2011). Regulation of Sororin by Cdk1-mediated phosphorylation. J Cell Sci.124: 2976-87. (highlighted in “In This Issue” section of the journal)
Kaur, H, Bekier ME, and Taylor, WR. (2010). Regulation of Borealin by Phosphorylation at Serine 219. Journal of Cellular Biochemistry. J Cell Biochem. 111:1291-8
Bekier ME, Fischbach, R, Lee, L and Taylor, WR. (2009). Length of mitotic arrest induced by microtubule stabilizing drugs determines cell death after mitotic exit. Molecular Cancer Therapeutics 8: 1646-1654.
Dreier MR, Grabovich AZ, Katusin JD, Taylor WR. (2009). Short and long-term tumor cell responses to Aurora kinase inhibitors. Exp Cell Res. 315: 1085-99
Kosik A, Bekier ME, Katusin JD, Kaur H, Zhou X, Diakonova M, Chadee DN, Taylor WR. (2009). Investigating the role of Aurora kinases in RAS signaling. J Cell Biochem. 106:33-41.
Date, DA, Jacob CJ, Bekier, ME, Stiff, AC, Jackson, MW and Taylor, WR. (2007). borealin is repressed in response to p53/Rb signaling. Cell Biology International 31: 1470-1481.
Kaur, H, Stiff, A, Date, D, and Taylor, WR. (2007).Analysis of mitotic phosphorylation of borealin. BMC Cell Biology 8:5. (17p)(selected as Image of the Month, and Highly Accessed).
Stark, GR and Taylor, WR. (2006). Control of the G2/M transition. Molecular Biotechnology. 32:227-48.
Jackson, MW, Agarwal, MK, Yang, J, Bruss, P, Uchiumi, T, Agarwal, ML, Stark, GR and Taylor, WR. (2005). p53/Rb-dependent transcriptional repression during cell cycle exit at G2. J. of Cell Science 118: 1821-1832.
Clifford, B, Beljin, M, Stark, GR, and Taylor, WR. (2003). G2 arrest in response to topoisomerase II inhibitors: The role of p53. Can. Res. 63: 4074–4081.
Taylor, WR, Schonthal, AH, Galante, J, and Stark GR. (2001). p130/E2F4 binds to and represses the cdc2 promoter in response to p53. J. Biol. Chem. 276: 1998–2006.
Taylor, WR, Agarwal, ML, Agarwal, A, Stacey, DW, and Stark, GR. (1999a). p53 inhibits entry into mitosis when DNA synthesis is blocked. Oncogene 18: 283-296.
Taylor, WR, DePrimo, SE, Agarwal, A, Agarwal, ML, Schonthal, AH, Katula, KS, and Stark GR. (1999b). Mechanisms of G2 arrest in response to overexpression of p53. Mol. Biol. Cell 10: 3607-3622.
Agarwal, ML, Agarwal, A, Chernova, OB, Taylor, WR, Sharma, YK, and Stark, GR. (1998a). A p53-dependent S-phase checkpoint protects cells lacking a G1 checkpoint from DNA damage in response to starvation for pyrimidine nucleotides. Proc. Natl. Acad. Sci. USA 95: 14775-14780.
Huang, A, Fan, H, Taylor, WR, and Wright, JA. (1997). Ribonucleotide reductase R2 gene expression and changes in drug sensitivity and genome stability. Cancer Res. 57: 4876-4881.
Agarwal, ML, Agarwal, A, Taylor, WR, and Stark, GR. (1995). p53 controls both G2/M and G1 cell cycle checkpoints and mediates reversible growth arrest in human fibroblasts. Proc. Natl. Acad. Sci. USA 92: 8493-8497.