First-in-Class Targeted microRNA Therapy Slows Cancer Tumor Growth

Cancer begins when cells in the body start to divide without control, often ignoring signals to stop dividing or die, and sometimes even dodging the immune system. A breakthrough cancer treatment now attacks tumors by tricking cancer cells into absorbing a specific RNA snippet that naturally inhibits cell division. During a 21-day study, tumors exposed to this treatment remained the same size, while those without treatment tripled in size.

The new cancer therapy was developed by researchers at Purdue University (West Lafayette, IN, USA) and has been trialed on mice. It employs a delivery system specifically aimed at cancer cells and uses a specially engineered form of microRNA-34a, a molecule likened to "brakes on a car" for its ability to halt cell division. MicroRNA-34a consists of a short, double-stranded sequence of ribonucleic acids linked together like a zipper along a sugar-phosphate backbone. The two strands of the microRNA are unevenly zipped, with one strand guiding a protein complex to its destination inside the cell while the other strand is broken down. In healthy cells, there is a high level of microRNA-34a, but this is significantly reduced in many cancer cells.

Image: A new therapy for cancer uses microRNA to slow or stop the division of cancer cells (Photo courtesy of Purdue University)

This targeted form of microRNA-34a doesn't just stall or reverse tumor growth; it also considerably suppresses the activity of at least three genes—MET, CD44, and AXL—that are known for fueling cancer and causing resistance to other cancer treatments. The suppression lasts for a minimum of 120 hours. This suggests that this new, patent-pending treatment, which has evolved from over 15 years of research into using microRNA to combat cancer, could be effective both as a standalone treatment and when used in conjunction with existing medications for treating drug-resistant cancers. An added benefit is that the engineered microRNA-34a is designed to be undetectable by the immune system, which usually targets and destroys double-stranded RNA introduced to the body.

“When we acquired the data, I was ecstatic. I am confident that this approach is better than the current standard of treatment and that there are patients who will benefit from this,” said Andrea Kasinski, a member of the Purdue Institute for Cancer Research.

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