Title: Functional analysis of structure specific nucleases in genome stability and cancers
Abstract
The goal of this application is to provide essential support for my research on the molecular basis of genomic
instability in cancer, which is conducted in the laboratory of Dr. Binghui Shen, Professor and Chair of Cancer
Genetics and Epigenetics at the Beckman Research Institute of City of Hope. It is my intention to leverage the
excellent resources available at City of Hope, and within an established laboratory, to maximize my ongoing
contribution to science, rather than build an independent research program from the ground up. Dr. Shen's
research program has been sponsored by two long-term continuously funded R01 grants, NCI R01 CA073764
(1997-2017) and NCI R01 CA085344 (1998-2018). Since I joined the Shen laboratory in 2001, I have co-
authored 32 of the 46 peer reviewed articles that are associated with these two research programs, including
manuscripts published in Nature Medicine, Molecular Cell, Nature Chemical Biology, and Nature
Communications. As an Assistant Research Professor of Cancer Genetics and Epigenetics, I bring to the Shen
laboratory expertise in protein biochemistry, cell culture assays of DNA repair, and mouse genetics, as well as
mentoring, project management, and manuscript preparation. My major contributions to the field of DNA
replication and repair, and their connection to cancer, include the biochemical characterization of mammalian
FEN1 and DNA2 and demonstration of FEN1 and DNA2 mutations as cancer etiological factors. The goal of
the NCI R01 CA073764 research program is to establish a comprehensive relationship among genetic
alterations, functional deficiency, and pathological consequences, using FEN1 nuclease as a model protein
and transgenic mice as a model system. During the previous funding cycles, we evaluated FEN1 mutations
using cancer cells and transgenic knock-in mice that disrupt FEN1's nuclease activities, protein/protein
interactions and post-translational modifications (PTMs), and contribute to tumorigenesis. In the current
funding cycle, we are investigating the role of FEN1 PTMs in genome maintenance during DNA replication and
their potential role in cancer. Meanwhile, the goal of the NCI R01 CA085344 research program is to define the
roles of the DNA2 nuclease/helicase in genome integrity and tumor suppression. We have found that the role
of DNA2 extends beyond the previously established role in Okazaki fragment maturation; it also stabilizes
stalled DNA replication forks, repairs collapsed DNA replication forks, participates in telomere replication,
regulates mtDNA repair, and regulates cancer development. We are currently testing the hypothesis that PTMs
on mammalian DNA2 regulate its response to DNA replication stress from both exogenous and endogenous
sources. As part of this project, I am establishing and testing new mouse models with DNA2 mutations that
have been identified in human cancers. This funding support will allow me to continue my work on the
established research programs in the Shen laboratory and will provide autonomy to pursue important novel
lines of research that will form the basis of future collaborative funding proposals.