POSITION TITLE: Associate Professor of Biochemistry, Cell Biology and Cancer Biology

Transcription

1 OMB No /0002 (Rev. 08/12 Approved Through 8/31/2015) BIOGRAPHICAL SKETCH Provide the following information for the Senior/key personnel and other significant contributors. Follow this format for each person. DO NOT EXCEED FIVE PAGES. NAME: Liu, Xiaoqi era COMMONS USER NAME (credential, e.g., agency login): XIAOQILIU POSITION TITLE: Associate Professor of Biochemistry, Cell Biology and Cancer Biology EDUCATION/TRAINING (Begin with baccalaureate or other initial professional education, such as nursing, include postdoctoral training and residency training if applicable. Add/delete rows as necessary.) INSTITUTION AND LOCATION DEGREE (if applicable) Completion Date MM/YYYY FIELD OF STUDY Peking University B.S. 07/1991 Chemistry Chinese Academy of Science M.S. 07/1994 Biophysics Washington State University Ph.D. 05/1999 Biochemistry Harvard University Postdoctoral 04/2006 Cell Biology A. Personal Statement I have a broad background in cancer biology, with specific training and expertise in signaling transduction, cell cycle regulation, drug resistance and DNA damage repair. As PI or co-investigator on several university-, NSFand NIH-funded grants, I laid the groundwork for the proposed research by providing key preliminary data. I received my Ph.D. in Dr. Michael Smerdon s lab in Washington State University in 1999 by working on DNA repair of UV-induced DNA damage. As a graduate student, I examined mutual effects of UV-induced DNA photoproduct formation in 5S rdna and transcription factor IIIA binding, analyzed the effect of TFIIIA binding on nucleotide excision repair, and determined the modulation of DNA damage and repair by nucleosome folding. I had a solid publication record as a graduate student in DNA damage repair (Liu & Smerdon, Anal. Biochem. 1995; Liu et al., Biochemistry 1997; Conconi et al., EMBO J. 1999; Liu et al., Biochemistry 2000; Liu & Smerdon, J. Biol. Chem. 2000). I did my post-doctoral training with Dr. Raymond Erikson at Harvard University by working on signal transduction in mitosis, particular polo-like kinase 1 (Plk1). During that period, I systematically analyzed Plk1 lossof-function phenotypes in mammalian cells (Liu & Erikson, PNAS 2002; Liu & Erikson, PNAS 2003; Liu et al., Mol Cell Biol 2005). I examined how Plk1 phosphorylation of mitotic kinesin-like protein CHO1/MKLP-1 regulates cytokinesis (Liu et al., J Cell Sci. 2004) and studied the crosstalk between Plk1 and the MAP kinase pathway (Liu et al., Oncogene 2004). I started my independent laboratory at Purdue in 2006 by focusing on understanding the regulation of Plk1 during cell cycle progression. After 2006, I have made the following contributions to the scientific community: 1). Validation of Plk1 as a target for cancer therapy, specifically late stage prostate cancer. 2) Identification of Chk1 and MK2 as two upstream regulators of Plk1. 3) Identification of Plk1 substrates in various cellular processes. Among a series of Plk1 substrates we have identified, Hbo1 and Orc2 are two members of DNA replication machinery, DNA topoisomerase IIα and TRF1 are essential for chromosome dynamics, Clip-170 and Sgt1 are involved in kinetochore-microtubule attachments, p150 Glued is required for nuclear envelope breakdown, Topors and GTSE1 are two p53 regulators in response to DNA damage, and PTEN is the major regulator of cancer metabolism. In short, I have established my reputation as one of major contributors of the Plk1 field over the last decade. After 2010, I started to closely collaborate with colleagues with expertise in mouse genetics and human pathology and have successfully generated a series of genetically engineered mouse lines. As a result of these previous experiences, I am aware of the importance of frequent communications among project members and of constructing a realistic research plan, timeline, and budget. My current research focuses on basic mechanism of cancer therapeutics. a. Tang, J., Erikson, R. L. and Liu, X. (2006) Checkpoint kinase 1 (Chk1) is required for mitotic progression through negative regulation of polo-like kinase 1 (Plk1). Proc. Natl. Acad. Sci. USA 103, PMID:

2 b. Tang, J., Yang, X. and Liu, X. (2008) Phosphorylation of Plk1 at Ser326 regulates its functions during mitotic progression. Oncogene. 27, PMID: c. Chen, L., Li, Z., Ahmad, N. and Liu, X. (2015) Plk1 phosphorylation of IRS2 prevents premature mitotic exit via AKT inactivation. Biochemistry 54, PMID: d. Shao, T. and Liu, X. (2015) Identification of Rictor as a novel substrate of polo-like kinase 1. Cell Cycle 14, PMID: B. Positions and Honors Positions and Employment Research Assistant, Washington State University, Pullman, WA Dr. Michael Smerdon Post-doctoral fellow, Harvard University, Cambridge, MA Dr. Raymond Erikson Assistant professor, Purdue University, West Lafayette, IN Associate professor, Purdue University, West Lafayette, IN Professional Memberships Member, American Society for Cell Biology Member, American Association for Cancer Research Honors 2004 Don Wiley Award provided by Merck 2005 Howard Temin Award from NIH 2013 The American Cancer Society Research Scholar (lifetime honor) 2013 Ad hoc Member Basic Mechanism of Cancer Therapeutics NIH Study Section Editorial Board Member of Journal of Biological Chemistry Associate Editor of Cancer Medicine C. Contributions to Science 1. Plk1 is a valid target for cancer therapy. To address the question whether Plk1 is a good target for cancer therapy, I once systematically analyzed Plk1 depletion-induced phenotypes in mammalian cells with various approaches, including direct transfection of dsrna, vector-based shrna and lentivirus-based shrna. I showed that Plk1 depletion led to mitotic arrest, followed by apoptosis in almost all the cancer cell lines I analyzed, as indicated by multiple phenotypes, such as activation of Cdc2/cyclin B, formation of monopolar spindle, and elevation of cleaved form of caspase 3. In striking contrast, normal cells were much less sensitive to Plk1 depletion than cancer cells; no apparent cell proliferation or cell cycle arrest was observed after Plk1 depletion. Of significance, non-transformed cells became sensitive to Plk1 depletion upon loss of tumor suppressor p53, a hallmark of many cancers. Our initial finding that non-transformed cells were much more resistant to Plk1 depletion/inhibition than cancer cells was later independently confirmed by many other investigators. Collectively, these data suggest that Plk1 may be a feasible cancer therapeutic target. These work has been cited extensively by many Plk1 papers over the last decade. Our more recent work showed that inhibition of Plk1 represses androgen signaling pathway in prostate cancer cells and that co-targeting of Plk1 and the Wnt/ -catenin signaling pathway is a valid approach to treat castration-resistant prostate cancer. Finally, activation of Plk1 plays a critical role in low-dose arsenic-mediated metabolic shift. I served as the primary investigator in all of these studies. a. Liu, X., Lei, M. and Erikson, R. L. (2006) Normal cells, but not cancer cells, survive severe Plk1 depletion. Mol. Cell. Biol. 26, PMID: b. Zhang, Z., Chen, L., Wang, H., Ahmad, N. and Liu, X. (2015) Inhibition of Plk1 represses androgen signaling pathway in castration-resistant prostate cancer. Cell Cycle 14, PMID: c. Li, Z., Lu, Y., Ahmad, N., Strebhardt, K. and Liu, X. (2015) Low-dose arsenic-mediated metabolic shift is associated with activation of Polo-like kinase 1. Cell Cycle 14, PMID: d. Li, J., Karki, A., Hodges, K.B., Ahmad, N., Zoubeidi, A., Strebhardt, K., Ratliff, T.L., Konieczny, S.F. and Liu X. (2015) Co-targeting Polo-like kinase 1 (Plk1) and the Wnt/ -catenin signaling pathway in castration-resistant prostate cancer. Mol. Cell. Biol. [E-pub ahead of print]. PMID: Plk1 plays a critical role in chromosome dynamics. Soon after my independence in 2006, we observed that Plk1 is mainly localized in the nucleus of interphase transformed cells. Of note, this novel finding was later independently confirmed by other labs. To dissect nuclear functions of Plk1, we identified four novel substrates with documented roles in chromosome dynamics. We showed that Plk1 phosphorylation of DNA

3 topoisomerase II enhances its decatenation activity towards DNA, an essential molecular event in late S phase after DNA replication. Consequently, expression of Plk1 unphosphorylatable topoisomerase II mutant led to defects in sister chromatid segregation and activation of DNA damage checkpoint. We then showed that Plk1 phosphorylates TRF1, a negative regulator of telomere length, and that Plk1 phosphorylation of TRF1 is essential for its association to telomeres. More significantly, we showed that Plk1 phosphorylates Hbo1 and Orc2, two members of DNA replication machinery, and that Plk1 phosphorylation of Hbo1 and Orc2 leads to increased DNA synthesis under specific cellular contexts. Mechanistically, Plk1 phosphorylation of Hbo1 is required for G1/S transition and chromatin loading of the minichromosome maintenance (McM) complex. Plk1 phosphorylation of Orc2 promotes its association with DNA replication origin, thus to maintain the functional pre-replicative complex even under DNA replication stress. Thus, these work provides direct evidence that Plk1 is directly involved in DNA metabolic events, such as DNA decatenation, telomere enlongation, and DNA replication. a. Li, H., Wang, Y. and Liu, X. (2008) Plk1-dependent phosphorylation regulates functions of DNA topoisomerase IIα in cell cycle progression. J. Biol. Chem. 283, PMID: b. Wu, Z., Yang, X., Weber, G. and Liu, X. (2008) Plk1 phosphorylation of TRF1 is essential for its binding to telomeres. J. Biol. Chem. 283, PMID: c. Wu, Z. and Liu, X. (2008) A role for Plk1 phosphorylation of Hbo1 in regulation of replication licensing. Proc. Natl. Acad. Sci. USA.105, PMID: d. Song, B., Liu, X. S., Davis, K. and Liu, X. (2011) Plk1 phosphorylation of Orc2 promotes DNA replication under conditions of stress. Mol. Cell. Biol. 31, PMID: Plk1 regulates kinetochore-microtubule attachments and nuclear envelopment breakdown. Our initial observation that Plk1 depletion induces mitotic catastrophe was later independently confirmed by many other labs. But the exact role of Plk1 during different stages of mitosis remained elusive. To ask questions like how Plk1 depletion leads to monopolar spindle formation, we identified three novel Plk1 substrates, Clip-170, p150 Glued, and Sgt1. Clip-170 is implicated in the formation of kinetochore-microtubule attachments through direct interaction with the dynein/dynactin complex, in which p150 Glued is a major component. While both Clip- 170 and p150 Glued are microtubule plus-end binding proteins, Sgt1 is a cochaperone for Hsp90. We showed that Plk1 phosphorylation of Clip-170 promotes its binding to and further phosphorylation by CK2 and that CK2-dependent phosphorylation of Clip-170 in turn enhances its interaction with the dynein/dynactin complex, eventually contributing to kinetochore-microtubule attachments. We also showed that Plk1 enhances the kinetochore localization of Sgt1 and that subsequent Plk1 phosphorylation of Sgt1 increases the chaperone activity of Hsp90-Sgt towards the Mis12 complex, the key kinetochore component. Finally, we showed that Plk1 phosphorylation of p150 Glued facilitates nuclear envelop breakdown during prophase. I served as the principal investigator in all of these studies. a. Yang, X., Li, H., Liu, X.S., Deng, A. and Liu, X. (2009) Cdc2-mediated phosphorylation of Clip-170 is essential for its inhibition of centrosome reduplication. J. Biol. Chem. 284, PMID: b. Li, H., Liu, X.S., Yang, X., Wang, Y., Wang, Y., Turner, J.R. and Liu, X. (2010) Phosphorylation of Clip- 170 by Plk1 and CK2 promotes timely formation of kinetochore-microtubule attachments. EMBO J. 29, PMID: c. Li, H., Liu, X.S., Yang, X., Wang, Y., Song, B. and Liu, X. (2010) Plk1 phosphorylation of p150 Glued facilitates nuclear envelope breakdown during prophase. Proc. Natl. Acad. Sci. USA 107, PMID: d. Liu, X. S., Tang, J., Song, B., Liu, W., Kuang, S. and Liu, X. (2012) Plk1 phosphorylates Sgt1 at the kinetochores to promote the timely kinetochore-microtubule attachment. Mol. Cell. Biol. 32, PMID: Plk1 elevation leads to inactivation of key tumor suppressors. Having established that Plk1 is a valid target for cancer therapeutics, we then asked how Plk1 elevation directly contributes to tumorigenesis. Toward that end, we turned our attention to two most important tumor suppressors: p53 and PTEN. Tumor suppressor p53, whose loss-of-function mutations are found in 50% of human cancers, is called guardian of the genome. We discovered a mechanism to explain a long-term puzzle of the field, how oncogenic Plk1 inhibits the tumor suppressing function of p53. We showed that Plk1 phosphorylation of Topors and GTSE1, two regulators of p53, contributes to downregulation of p53 in cancer cells. Activation of the PI3K/AKT/mTOR pathway due to PTEN inactivation is another common event in many cancers. We showed that Plk1 directly

4 phosphorylates PTEN and that Plk1 phosphorylation of PTEN leads to its inactivation, thus activation of the PI3K/AKT/mTOR pathway. Cancer cells maintain tumor growth through increased glycolysis (Warburg effect) and glutaminolysis (glutamine addition) to satisfy the energy and carbon backbone needs, respectively. However, the molecular mechanisms underlying the Warburg effect and glutamine addition have not been completely understood. Of significance, we showed that Plk1 phosphorylation of PTEN leads to a tumorpromoting metabolic state. These findings provide one likely explanation of how Plk1 overexpression leads to cancer formation. I served as the principal investigator in all of these studies. a. Yang, X., Li, H., Zhou, Z., Wang, W., Deng, A., Andrisani, O. and Liu, X. (2009) Plk1-mediated phosphorylation of Topors regulates p53 stability. J. Biol. Chem. 284, PMID: b. Liu, X.S., Li, H., Song, B. and Liu, X. (2010) Polo-like kinase 1 phosphorylation of G2 and S-phaseexpressed 1 protein is essential for p53 inactivation during G2 checkpoint recovery. EMBO Rep. 11, PMID: c. Liu, X. S., Song, B., Elzey, B., Ratliff, T., Konieczny, S., Cheng, L., Ahmad, N. and Liu, X. (2011) Pololike kinase 1 facilitates loss of PTEN-induced prostate cancer formation. J. Biol. Chem. 286, PMID: d. Li, Z., Li, J., Bi, P., Lu, Y., Burcham, G., Elzey, B.D., Ratliff, T., Konieczny, S.F., Ahmad, N., Kuang, S. and Liu, X. (2014) Plk1 Phosphorylation of PTEN Causes a Tumor-Promoting Metabolic State. Mol. Cell. Biol. 34(19) PMID: Inhibition of Plk1 overcomes therapy resistance. Several Plk1 inhibitors have been developed and in heavy clinical trials over the last decade. Unfortunately, it was largely concluded that monotherapy with Plk1 inhibitor alone has very limited therapeutic benefit. Therefore, we asked the next important question whether inhibition of Plk1 can enhance the efficacy of existing drugs, including gemcitabine in pancreatic cancer and docetaxel, androgen signaling inhibitors (ASI), and metformin in castration-resistant prostate cancer (CRPC). We showed that Plk1 phosphorylation of Orc2 and Hbo1 led to continued DNA replication in the presence of gemcitabine, thus eventually contributing to gemcitabine resistance in pancreatic cancer. Of significance, we further showed that inhibition of Plk1 overcomes gemcitabine resistance in both pancreatic cancer cells and tumors. We also showed that Plk1 phosphorylation of Clip-170 and p150 Glued enhances microtubule dynamics, thus contributing to docetaxel resistance. We then showed that Plk1 is a positive regulator of androgen receptor signaling, likely due to its ability to enhance de novo androgen biosynthesis. More significantly, we showed that inhibition of Plk1 sensitizes ASI-resistant CRPC cells to ASI and that inhibition of Plk1 and ASI inhibit patient-derived CRPC xenografts in a synergistic manner. This finding was highlighted by Nature Reviews Urology upon its publication. Metformin, a widely used anti-diabetic drug, has been shown to inhibit the development of CRPC in clinical trials. Of significance, we showed that inhibition of Plk1 enhances the antineoplastic activity of metformin in CRPC through both p53 and metabolic pathways. These findings suggest immediate clinical trials by combining Plk1 inhibitors with existing drugs to achieve the best outcome. I served as the principal investigator in all of these studies. a. Song, B., Liu, X.S., Rice, S., Elzey, B., Konieczny, S., Ratliff, T., Hazbun, T., Chiorean, E.G. and Liu, X. (2013) Plk1 phosphorylation of Orc2 and Hbo1 contributes to gemcitabine resistance in pancreatic cancer. Mol. Can. Ther. 12, PMID: b. Hou, X., Li, Z., Huang, W., Li, J., Staiger, C. Kuang, S., Ratliff, T. and Liu, X. (2013) Plk1-dependent microtubule dynamics promotes androgen receptor signaling in prostate cancer. The Prostate. 73, PMID: c. Zhang, Z., Hou, X., Shao, C., Li, J., Cheng, J., Kuang, S., Ahmad, N., Ratliff, T. and Liu, X. (2014) Plk1 inhibition enhances the efficacy of androgen signaling blockade in castration-resistant prostate cancer. Cancer Research 74, PMID: d. Shao, C., Ahmad, N., Hodges, K., Kuang, S., Ratliff, T. and Liu, X. (2015) Inhibition of polo-like kinase 1 (Plk1) enhances the anti-neoplastic activity of metformin in prostate cancer. J. Biol. Chem. 290, PMID: Complete List of Published Work in MyBibliography: on=ascending. D. Research Support Ongoing Research Support

5 1R01 CA A1 06/01/ /31/ academic National Institute of Health $1,937,500 Treatment of castration-resistant prostate cancer The goal of this project is to determine how Plk1-associated kinase activity regulates the WNT/ -catenin pathway in prostate cancer. 2R01 CA A1 02/01/ /31/ academic National Institute of Health $1,823,431 Overcoming drug resistance of castration-resistant prostate cancer The goal of this project is to test whether a combination of Plk1 inhibition and androgen signaling inhibitors is a novel approach to treat very late stage of prostate cancer. 1 R01 CA A1 02/01/ /31/ academic National Institute of Health $1,874,296 Enhancing anti-neoplastic activity of metformin in prostate cancer The goal of this project is to determine whether Plk1-associated kinase activity towards TSC1 contributes to resistance of metformin in prostate cancer. American Cancer Society 01/01/ /31/2016 Title: Plk1 in UV-induced melanoma formation The goal of this project is to understand how Plk1-associated kinase activity contributes to UV-induced DNA damage repair and melanoma formation. National Institute of Health (PI: Ahmad) 07/01/ /30/2020 Title: Role of Plk1 in melanocytic transformation The goal of this project is to understand how Plk1-associated kinase activity contributes to melanocytic transformation and melanoma initiation. National Institute of Health (PI: Ahmad) 07/01/ /30/2018 Title: Role of SIRT1 in melanocyte biology melanocytic transformation The goal of this project is to understand how SIRT1-associated enzymatic activity contributes to melanocytic transformation and melanoma initiation. Department of Defense (PI: Cheng) 10/01/ /30/2017 Title: Making aggressive prostate cancer quiescent by abrogating cholesterol esterification The goal of this project is to understand the role of cholesterol metabolism in prostate cancer progression. Completed Research Support National Institute of Health (R01 CA157429) 09/01/ /31/2014 Title: Plk1 in chemo-resistance in cancer The goal of this project is to understand how Plk1-associated kinase activity towards GTSE1 and Sgt1 affects cellular response to chemotherapy in cancer. National Science Foundation (MCB ) 04/01/ /31/2014 Title: Plk1 in DNA replication The goal of this grant is to investigate whether Plk1-associated phosphorylation of Hbo1 and Orc2 regulates DNA replication.