Imaging Technology Improves Responses to Cancer Therapy

Scientists have developed a highly sophisticated PET probe called [¹⁸F]CFA that for the first time can detect deoxycytidine kinase (dCK) activity in humans, according to a recent study.

“The quality of the images is much better,” said lead researcher Caius Radu. “We are able to clearly see tissues, including tumor tissues, with high dCK activity that we haven't seen before in humans using any of the other probes previously developed for this enzyme.”

In prior studies, the enzyme dCK was found to be highly expressed in acute leukemia cells and in activated lymphocytes. Additionally, it controls an important step in the nucleoside salvage pathway, which is an important therapeutic and PET imaging target in cancer.

However, other PET technology were unable to clearly detect dCK in mice because of metabolic instability and cross-reactivity with a dCK-related enzyme in humans.

A 7-year study published in Proceedings of the National Academy of Sciences of the United States of America developed [¹⁸F]CFA to better examine the dCK enzyme that plays a key role in allowing drugs to treat certain type of cancers. Furthermore, it could be used to help monitor the efficacy of immunotherapeutic interventions.

These drugs include Clofarabine, Cytarabine, and Fludarabine, which treats certain types of leukemia, and Gemcitabine, which treats breast, ovarian, pancreatic, and non-small cell lung cancer.

“This enzyme is essential for the therapeutic activity of an entire class of anticancer drugs and even for some antiviral drugs,” Radu said. “It can take an inactive drug and activate it. If you trick a cancer cell or virus to activate the drug, it would be toxic for the cancer cell or viral genome.”