Research in my lab is centered on studying the mechanisms of DNA replication in cancer cells and exploiting the results of this research for therapeutic purposes. Active projects focus on understanding the cellular functions and regulation of Cdc7 kinase (A) and on characterizing inhibitors of Cdc7 kinase activity in Multiple Myeloma and Chronic Lymphocytic Leukaemia (B). Recently we have developed a technique that will allow us to study how chromatin assembly is coupled with the duplication of DNA (C).

A) Cdc7 acts as a molecular switch for DNA synthesis and is also thought to participate in several other processes that regulate normal cell cycle progression and chromosome dynamics. Human Cdc7 has two cyclin-like binding partners which form either a Cdc7/Dbf4 complex or a Cdc7/Drf1 complex-their reciprocal roles are not yet defined. Biochemical, structural and functional approaches are employed to characterize the role of human Cdc7. Specific goals are:

Define reciprocal roles of the Dbf4 and Drf1 regulatory subunits
Identify new roles/substrates of the kinase
Determine the structure of kinase active site and other structural domains
Determine the impact of miRNA on Cdc7 activity
Key to these projects is the access to a MS/proteomic facility. A great effort was put into the development of in house infrastructure that can currently support both protein ID and phosphosite ID. This resource and protocols are made available to NUIG researchers.

B) Cdc7 inhibitors have shown antitumor activity in broad spectrum of preclinical cancer models including solid and leukemia xenografts, carcinogen induced and transgenic models. Phase I clinical studies are ongoing. A key question for this new class of drugs is to identify those cancer types in which they may be more efficacious. Together with Micheal O'Dwyer (Prof. of Hematology and Hospital consultant) we have been testing the activity and mechanism of action of Cdc7 inhibitors in cells from MM and CLL patents. Cellular co-culture systems that mimic the protective microenvironment niche of the lymph nodes have been developed for this purpose.

C) Replication of DNA and duplication of the epigenetic information are critical to the transmission of the genetic material from the parental cell to the two daughter cells and for specifying cell-type identity of the two daughter cells.  To investigate how these processes are regulated and coordinated, it is important to determine the identity of the proteins that are either stably or transiently associated with newly synthesized DNA. We have devised an experimental procedure that allows newly synthesized chromatin to be efficiently captured and analyzed. We have termed this DNA mediated chromatin pull-down (Dm-ChP). Dm-ChP is a highly specific and flexible technique. Current work is focused on identifying the protein component of newly synthesized chromatin and in assessing qualitative and quantitative changes in this protein fraction caused by the normal temporal program of DNA replication as well as by perturbation of the DNA replication machinery.

Cell Cycle, DNA replication, Cancer terapeutics