Cancer involves the induction of uncontrolled DNA replication and mitosis in cells, as well as processes that ensure cells evade cell death or senescence and survive in specific tissue micro-environments. Project 1 has been a leader in studying the mechanisms and control of inheritance of the human genome and has identified many of the key proteins that are involved in DNA synthesis at the replication fork and other proteins that are involved in the initiation of DNA replication. In the proposed studies. Project 1 will continue to focus on how the initiation of DNA replication is controlled in human cells and how this process goes awry in tumor cells.
Specific Aim 1 will focus on how the origins of DNA replication are marked in chromosomes so that they can form pre-replicative complexes during exit from mitosis or during Gl phase, thereby enabling the initiation of DNA replication in S phase of the cell division cycle. Since the Origin Recognition Complex, particularly its largest subunit Orel is loaded onto chromosomes beginning in prophase of mitosis and Orel is the most stably bound chromatin protein, the locations within the human genome for Orel binding will be determined. In addition, proteins that dynamically interact with ORC during M and G1 phases will be determined. The cell cycle regulators Cyclin E-CDK2 and Cyclin A-CDK2, the former often over-active in breast cancer, are controlled by direct interactions with Orel and Cdc6 and how these interactions influence the initiation of DNA replication and centriole duplication in centrosomes will be investigated. Recent evidence has emerged that ORC subunits play a critical role at kinetochores that bind microtubule spindles for congression of chromosomes prior to their segregation.
In Specific Aim 2, interactions between the Orc2 and Orc3 subunits of ORC and the Spindle Assembly Checkpoint kinase BubRI will be investigated, as will the role of the ORC subunits in maintenance of stable spindle attachment during the metaphase to anaphase transition.
In Specific Aim 3, the control of DNA replication by the DEAD-box RNA helicase DDX5 and its interaction with the transcription factor E2F1 will be studied. DDX5 is amplified in the genome of cells in 25% of human breast cancers and it is these cells that display selective sensitivity to inhibition of DDX5 protein levels. How DDX5 influences E2F1-driven expression of DNA replication genes in the Gl phase of the cell cycle will be investigated. Project 1 will also investigate how tumor cells with amplified copy number of DDX5 become addicted to its continued expression, in contrast to normal, non-tumor cells and many other cancer cells. Finally, the additive effects on inhibition of tumors cell proliferation with the combination of DDX5 depletion and Trastuzumab (Herceptin) treatment will be examined.

Public Health Relevance

One universal characteristic of cancer cells is that they have lost many of the regulatory mechanisms that control DNA replication and progression through mitosis, offering the potential to selectively target tumors cells for therapy. Understanding processes of genome duplication and segregation and how they are regulated in normal and cancer cells is of importance. Project 1 will investigate how the Origin Recognition Complex is involved in many aspects of the chromosome inheritance cycle and how the DDX5 RNA helicase controls this cycle in breast cancers.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Program Projects (P01)
Project #
Application #
Study Section
Special Emphasis Panel (ZCA1-RPRB-0 (O1))
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Cold Spring Harbor Laboratory
Cold Spring Harbor
United States
Zip Code
Knott, Simon R V; Wagenblast, Elvin; Khan, Showkhin et al. (2018) Asparagine bioavailability governs metastasis in a model of breast cancer. Nature 554:378-381
Shamay, Yosi; Shah, Janki; I??k, Mehtap et al. (2018) Quantitative self-assembly prediction yields targeted nanomedicines. Nat Mater 17:361-368
Tramentozzi, Elisa; Ferraro, Paola; Hossain, Manzar et al. (2018) The dNTP triphosphohydrolase activity of SAMHD1 persists during S-phase when the enzyme is phosphorylated at T592. Cell Cycle 17:1102-1114
Arun, Gayatri; Diermeier, Sarah D; Spector, David L (2018) Therapeutic Targeting of Long Non-Coding RNAs in Cancer. Trends Mol Med 24:257-277
Tarumoto, Yusuke; Lu, Bin; Somerville, Tim D D et al. (2018) LKB1, Salt-Inducible Kinases, and MEF2C Are Linked Dependencies in Acute Myeloid Leukemia. Mol Cell 69:1017-1027.e6
Xu, Yali; Milazzo, Joseph P; Somerville, Tim D D et al. (2018) A TFIID-SAGA Perturbation that Targets MYB and Suppresses Acute Myeloid Leukemia. Cancer Cell 33:13-28.e8
Huang, Yu-Han; Klingbeil, Olaf; He, Xue-Yan et al. (2018) POU2F3 is a master regulator of a tuft cell-like variant of small cell lung cancer. Genes Dev 32:915-928
Livshits, Geulah; Alonso-Curbelo, Direna; Morris 4th, John P et al. (2018) Arid1a restrains Kras-dependent changes in acinar cell identity. Elife 7:
Tiriac, Hervé; Belleau, Pascal; Engle, Dannielle D et al. (2018) Organoid Profiling Identifies Common Responders to Chemotherapy in Pancreatic Cancer. Cancer Discov 8:1112-1129
Bhagwat, Anand S; Lu, Bin; Vakoc, Christopher R (2018) Enhancer dysfunction in leukemia. Blood 131:1795-1804

Showing the most recent 10 out of 610 publications