As reported today in Oncogene, tumors treated with the new therapy did not increase in size over the course of a 21-day study, while untreated tumors tripled in size over the same time period.
In addition to slowing or reversing tumor growth, the targeted microRNA-34a strongly suppressed the activity of at least three genes – MET, CD44 and AXL – known to drive cancer and resistance to other cancer therapies, for at least 120 hours.
MicroRNA-34a is a short double strand of ribonucleic acid – a string of ribonucleic acids attached like the teeth of a zipper along the length of a sugar-phosphate chain. The two strings of the microRNA are unevenly zipped together, with one string acting to guide a protein complex to the worksite in the cell while the other string is destroyed.
Related StoriesThe team modeled its modifications on an FDA-approved chemical structure that researchers at the biotechnology company Alnylam used on similar short interfering RNAs. Experiments on mouse models show the modified microRNA-34a endures for at least 120 hours after being introduced. The tiny microRNA-34a and folate compound penetrates the dense tissue of tumors and binds to the folate receptor on the cell surface. It is then drawn inside in a little bag of cell membrane called a vesicle. Once inside the cell, some of the microRNA-34a is able to escape the vesicle and slows cell division.