Pitt Researchers at UPMC Hillman Cancer Center Demonstrate They Can Turn Cancer Cells Off

January 5, 2026

A team of researchers from the University of Pittsburgh at UPMC Hillman Cancer Center has demonstrated they can turn off cancer cells instead of just killing them in a new publication in PNAS.

The study led by Masashiro Shuda, PhD, showed that treating Merkel cell carcinoma cells caused by Merkel cell polyomavirus with small molecule inhibitors that block CBP/p300 shuts off the viral protein production in cancer cells. These drugs cause the cancer cells to stop dividing and start behaving more like normal cells.

Human Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine skin cancer, and the majority of MCC is caused by Merkel cell polyomavirus. Many virus-induced cancers depend on a driver, known as “oncogenic addiction,” to sustain their malignant phenotype. As a result, viral oncoproteins are logical targets for cancer prevention and therapy.

In this study, the researchers demonstrate that pharmacological inhibition of CBP/p300 coactivators suppresses oncogene expression, efficiently converting MCC cells to a dormant nerve cell phenotype in an experimental cell culture model. Further, they identified rare tumors in patients that contained both conventional MCC cells and adjacent nerve cells that had lost viral protein expression, confirming that the conversion of MCC cells into nerve cells due to the loss of viral proteins occurs even within human skin. This discovery provides an exciting opportunity for new therapies that can make MCC tumor cells stop acting like cancer and start acting more like normal cells again — kind of like flipping a switch in the cell’s behavior.

Other contributors to the study were from the University of Pittsburgh departments of human genetics and pathology, the German Cancer Consortium of the University Medicine Essen, and “Biologie des infections à polyomavirus” Team from the Université de Tours in France.

The research was supported by the University of Pittsburgh Health Sciences Bridge Funding Program, the National Institute of Allergy and Infectious Diseases (1R01AI181892), NIH Cancer Center Support Grant (P30CA047904), and the German Cancer Consortium BMBF ED003.