For the first time, researchers have shown that an enzyme key to regulating gene expression -- and also an oncogene when mutated -- is critical for the expression of numerous inflammatory compounds that have been implicated in age-related increases in cancer and tissue degeneration, according to new research from the Perelman School of Medicine at the University of Pennsylvania. Inhibitors of the enzyme are being developed as a new anti-cancer target.

Aged and damaged cells frequently undergo a form of proliferation arrest called cellular senescence. These fading cells increase in human tissues with aging and are thought to contribute to age-related increases in both cancer and inflammation. The secretion of such inflammatory compounds as cytokines, growth factors, and proteases is called the senescence-associated secretory phenotype, or SASP.

In a study published this week in Genes & Development, genetic and pharmacological inhibition of the enzyme, called MLL1, in both human cells and mice prevents the deleterious activation of the DNA damage response, which causes SASP expression.

“Since tumor-promoting inflammation is one of the hallmarks of cancer, these findings suggest that MLL1 inhibitors may be highly potent anti-cancer drugs through both direct epigenetic effects on proliferation-promoting genes, as well as through the inhibition of inflammation in the tumor microenvironment,” says first author Brian Capell, MD, PhD, a medical fellow in the lab of Shelley Berger, PhD, the Daniel S. Och University Professor in the Departments of Cell & Developmental Biology, Genetics , and Biology.

Berger is also the director of the Penn Epigenetics Program. Capell is an instructor and attending physician in the Department of Dermatology and is a postdoctoral fellow in the Berger lab.

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