Researchers Link Biomarker To Cancer Drug Resistance

Researchers at the University of California, San Diego School of Medicine have announced the discovery of a biomarker named CD61. Biomarker CD61 is found on the surface of drug-resistant tumors, and researchers believe that it enhances the stem cell-like properties of cancer cells and prompts tumor metastasis.

The research was led by David Cheresh, professor of Pathology at UC San Diego, as well as the university’s associate director for Innovation and Industry Alliances at the Moores Cancer Center. “There are a number of drugs that patients respond to during their initial cancer treatment, but relapse occurs when cancer cells become drug-resistant,” said Cheresh. “We looked at the cells before and after they became resistant and asked, 'What has changed in the cells? The good news is that we’ve uncovered a previously undefined pathway that the tumor cells use to transform into cancer stem cells and that enable tumors to become resistant to commonly used cancer drugs”

Cheresh’s research team looked at how tumor cells became resistant to receptor tyrosine kinase inhibitors such as erlotinib or lapatinib, which are common in a variety of cancer therapies. The researchers found that drug resistance starts when tumor cells acquire stem-cell like properties which allow them to “ignore” the drugs and survive and multiply throughout the body.

Hatim Husain, MD, who works as an assistant professor at the Moores Cancer Center, has designed a clinical trial to work on attacking the newly discovered pathway. “Resistance builds to targeted therapies against cancer, and we have furthered our understanding of the mechanisms by which that happens,” said Husain. “Based on these research findings we now better understand how to exploit the ‘Achilles heel’ of these drug-resistant tumors.  Treatments will evolve into combinational therapies where one may keep the disease under control and delay resistance mechanisms from occurring for extended periods of time.”

The findings for this study were published this week in the online issue of Nature Cell Biology.