University of Kentucky

Current Members

John D'Orazio, MD, PhD, Professor, Pediatrics

John, the principal investigator of the laboratory, is a physician scientist who combines a clinical career in pediatric hematology/oncology, caring for children with cancer and blood diseases, with melanoma and melanocyte research. His clinical interest is inherited cancer predisposition syndromes and the development of rational cancer-preventive strategies. His research interest is in melanoma predisposition and the role of the melanocortin 1 receptor (MC1R) signaling pathway in UV and cancer resistance. The D'Orazio lab studies various aspects of MC1R signaling and how pharmacologic replacement of MC1R signaling might protect cancer-prone persons from developing melanoma. John established the lab in 2004.

Stuart Jarrett, PhD, Assistant Professor, Toxicology and Cancer Biology

Stuart has long been interested in molecular and biochemical mechanisms of DNA repair systems. He has a background in mitochondrial DNA damage and oxidative stress, but more recently turned his attentions to melanoma and ultraviolet radiation (UV). He developed a murine model of UV-induced melanoma metastasis in his post-doctoral work with Dr. David Kaetzel. He joined the D'Orazio group in 2012 and discovered that PKA phosphorylates ATR in association with an AKAP12 scaffold downstream of MC1R/cAMP signaling in melanocytes. This event recruits XPA and accelerates nucleotide excision repair and reduces UV mutagenesis. His ongoing work is continuing to elucidate how cAMP signaling impacts melanocyte genomic stability. Stuart joined the lab in 2012.

Katharine Carter, Technician

Kati joined the laboratory in the Summer of 2016 with a wealth of experience in microbiology and chemistry laboratories. She is an undergraduate Biology student at the University of Kentucky with a love of science and exceptional bench skills. She takes pride in her work, keeps the lab running smoothly and helps everyone in their work. She has become an expert in culturing primary and transformed melanocytes and skillfully performs HPRT mutagenesis assays with accuracy and precision. She is well-organized and is a natural problem solver. We are delighted to have her in our lab. Kati joined the lab in 2016.

Nathaniel Holcombe, Ph.D., Post-doctoral Fellow

Nathaniel brings a wealth of DNA repair experience to the laboratory. His graduate work in the lab of Dr. Isabel Mellon (the person who discovered transcription-coupled repair in her post-doc with Dr. Phil Hanawalt) established a link between environmental carcinogens and impaired genomic stability caused by lower expression of XPC, a key nucleotide excision repair factor that is critical to damage recognition in global genome repair. In the D’Orazio lab, Nathaniel is studying the regulation of PKA-ATR-XPA DNA repair axis and its broader impact on melanocyte physiology. Nathaniel joined the lab in 2017.

Anna Overmann (Heink), B.S., M.S.

Anna is a University of Kentucky medical student who joined the lab in 2018. Prior to entering medical school, Anna completed graduate work in Zoology at Washington State University, where she studied oxidative damage and Sod-1 gene variation in rainbow trout. She then spent several years working at Cincinnati Children's Hospital as a technician, investigating the effects of high density lipoprotein heterogeneity on the development of cardiovascular disease in adolescents with diabetes and obesity. Anna is currently studying the impact of ATR mutations on oncogenesis and tumor progression.

Robert-Marlo Bautista, M.D., Surgical Research Fellow

Robert is a surgeon scientist in training who joined the lab on a T32 training award after his second year of general surgery residency. With a long-term interest in pediatric surgery, Robert has taken on a translationally-relevant project evaluating ATR mutations isolated in human melanoma samples. Robert is also evaluating novel sunscreen preparations as UV-protective compounds in an animal model of the fair-skinned human. Robert joined the lab in July 2017.

Maddy Krentz Gober, Ph.D., Post-doctoral Fellow

Trained as a pharmaceutical scientist concentrating in pharmacogenomics, Maddy joined the lab fresh out of her Ph.D. work in Penni Black's lab where she studied differential gene expression and signaling pathway activation between lung cancers with divergent responses to EGFR-targeting therapies. Her prior work identified an alternative combination of therapeutic targets for the treatment EGFR-inhibitor resistant lung cancers. Her interests in systems biology and "big data" led her to a project in the lab determining the broad impact of cAMP signaling on melanocyte metabolism. Maddy joined the lab in August 2017.