The formation of mutations in cellular DNA lies at the heart of cancer and its treatment. Patients diagnosed
with the deadliest solid tumors undergo treatment based on the alterations of DNA sequence in their cancer,
and further mutations that occur during treatment cause all-too-common adverse outcomes, including the
emergence of drug resistance and metastasis. Of course, these DNA alterations are responsible for the
genesis of malignancies in the first place, as accumulated mutations in driver genes lead to uncontrolled
growth. Strategies for suppressing mutagenesis can be important for preventing cancer in at-risk populations,
and for limiting the emergence of drug resistance and metastasis in existing cancer patients.
Here we propose to test a new, molecularly targeted approach to agents that suppress this adverse
mutagenesis. Our strategy is based on the most common molecular origins of these cancers: namely, point
mutations that arise from specific forms of DNA damage. Our specific aims for the four-year term of the project
are to develop new probes to quantify DNA damage in cells and tissues; to identify and develop new small-
molecule activators of the repair enzymes that repair the most common sources of mutations; to test whether
upregulating DNA repair can suppress the emergence of cancer drug resistance; and to test whether we can
lower the incidence of cancer in tumor-prone mice.
In progress leading up to this proposal, we have devised several novel and sensitive chemical probes as
first-in-class reporters that can measure the cellular activities of multiple DNA repair enzymes. We have
employed these probes in clinically relevant studies of cell and tumor specimens, and in investigating
connections between inflammation and DNA repair in animal models of disease. In addition, we have used
these probes to develop new small-molecule modulators of these pathways, including, excitingly, the only
known activators of some of these enzymes. Putting our experience together, we have developed new
hypotheses regarding how upregulating the activities of these pathways via small molecules can provide
biologically important, and potentially clinically useful, outcomes in cancer.
This research is important because it addresses the possibility of preventing common and deadly cancers
that remain difficult to treat. In addition, our team will develop molecular tools, including probes, assays, and
cell lines, that are likely to be useful to the cancer research community as a whole. Our research plan is
innovative in several ways: it will develop and apply new molecular tools for assessing damage and repair
pathways; it will lead to the development of the first small-molecule activators of multiple repair enzymes; and
it tests new hypotheses regarding how modulating repair activities will be helpful in treatment - and even
prevention - of these serious malignancies.