Jump Starting Cancer Drug Development

The April 12 issue of PNAS (Proceedings of the National Academy of Sciences) features a lead article by investigators at NYU, Cornell and Rational Therapeutics, on the identification of three compounds that inhibit the important cell signaling pathway known as WNT.

The WNT pathway was originally described in fruit flies as a determinate of wing shape. It was subsequently shown to be an important factor in human stem cell differentiation. Thereafter, its role in cancer was described. Certain colon cancers associated with a familial syndrome have a mutation in the WNT pathway. This results in an extremely high incidence of colon cancer. We now know that lung cancers, breast cancers, leukemias and lymphomas may share this pathway.

To date, there have been no clinical therapies available to treat WNT-driven tumors. Recognizing the importance of this pathway, the investigators at NYU and Cornell used a technology known as small interfering RNA (SIRNA) to shut down the WNT signal. They then screened 14,000 know chemicals for activity that mimicked the SIRNA effect. Three compounds were identified.

When the compounds showed activity in cell-lines that were WNT addicted, the investigators at NYU provided the compounds to Rational Therapeutics where we applied the EVA-PCD technique to measure activity in human tumor samples. The results confirmed activity and showed that several colon cancers, as well as other tumor types, had favorable profiles. The compounds were not uniformly effective, indicating that they were not simply toxins. Instead, they appeared to selectively injure cells that we assume are driven by WNT-related events.

The beauty of this study represents the introduction of a new paradigm of drug development. Following the elegant and highly sophisticated high throughput method employed by investigators at NYU and Cornell, these compounds were put to the very practical test of human relevance. The identification of activity in human tissues at concentrations similar to those associated with other classes of drugs, suggest that these novel compounds may have promise with these heretofore-untreatable cancers. This highly productive collaboration could prove a new model for the development of effective new therapies.