My laboratory studies cell cycle control in normal and cancer cells with an ultimate goal of discovering new approaches to prevent and treat cancer. Our focus is a protein kinase called ATR that is required for the replication checkpoint -- the means by which a cell ensures it does not undergo mitosis before completely replicating its DNA. Our prior work has demonstrated that loss of tumor suppressors such as p53 markedly sensitizes cells to death by inhibition of ATR function.

We are using cell culture, transgenic mouse and chemical genetic approaches to study:

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Updated Summary of Research Areas in the Lab:

There are two major areas of research in the Nghiem lab. The first is basic skin cancer biology focused on the replication checkpoint in cells. A particular interest is the molecular mechanism by which the protein kinase ATR mediates an essential cell cycle arrest following DNA damage such as by ultraviolet radiation. The second area involves basic, clinical and translational aspects of Merkel cell carcinoma, an uncommon, frequently lethal skin cancer associated with immune suppression, UV exposure and a newly describe polyomavirus.

Current effort on the replication checkpoint is centered on two topics.  First, the lab studies the in vivo effects of ATR inhibition in the replication checkpoint by chemical and genetic approaches. While not specific, caffeine is a known inhibitor of ATR and has been shown to sensitize cells to premature chromatic condensation (a hallmark of ATR inhibition). Current studies use in vivo mouse models and suggest that caffeine's relevant target after UV is ATR. Second, the lab has screened several chemical libraries to identify small molecule inhibitors of ATR. Current studies include verifying specificity and mechanisms of these novel inhibitors.

Current effort on Merkel cell carcinoma has clinical, basic and translational components. Clinical studies of Merkel cell carcinoma (MCC) involve a longitudinal database of ~250 patients and analysis of prognostic factors for development of a staging system. Basic and translational studies include a genome-wide analysis of MCC genetics and the identification of a candidate oncogene (manuscript submitted). Further, the lab is investigating the role of the newly described "Merkel cell polyomavirus" in MCC pathogenesis.