Two fundamental processes in biology—stem cell generation and carcinogenesis—are turning out to be closely intertwined. The lab of Richard Gregory, PhD, has been teasing out this relationship at the molecular level.
In 2008, Gregory and his colleagues showed how a factor called Lin28, which is associated with numerous cancers, makes a cell more prone to revert to a less specialized, stem-like state.
Lin28 acts by preventing maturation of Let-7—an ancient family of microRNAs found in creatures from humans to worms. Let-7 is the yin to Lin28’s yang: it causes stem cells to differentiate (embryonic stem cells, which are completely unspecialized, have very low levels of it). If a cell’s Let-7 can’t mature, it can’t differentiate; instead, it remains stem-like and can potentially become cancerous.
Suppressing Lin28 with RNA interference (RNAi) has been shown to suppress tumor growth. But Lin28 is difficult to target with drugs. …