US researchers have found that mini-molecules, called micro-RNA, might play a critical role in the progression of Chronic Myeloid Leukaemia (CML) from its treatable chronic phase to a life-threatening phase called as 'blast crisis'.
The study, led by Danilo Perrotti, assistant professor of molecular virology, immunology and medical genetics and a researcher with the Ohio State University Comprehensive Cancer Centre, also found an entirely new function for the mini-molecules.
With the study, the researchers showed that microRNAs could sometimes directly control a protein's function, not just whether or not the cell makes the protein, as has been believed.
The study, in which cells from CML patients in blast crisis were used, suggests that certain progenitor white blood cells are kept from maturing when levels of one microRNA, called miR-328, fall abnormally low.
Then immature white cells build up in the blood and bone marrow, a telltale sign that the patient has entered the therapy-resistant blast-crisis phase.
"If verified, our study suggests that altering microRNA levels might represent a potentially new therapeutic strategy for CML patients who do not benefit from effective targeted agents such as imatinib (Gleevec) and dasatinib (Sprycel)," said Perrotti.
"The findings also reveal a new function for microRNAs, which should further our understanding of their role in cancer development and progression, and in normal cells," Perrotti added.
This study shows that the microRNA molecules sometimes bind directly with proteins themselves and affect their function.
In this case, a microRNA called miR-328 binds with a protein that, in blast phase CML, prevents immature blood cells from maturing.
"These findings are important because they help us understand the biology of blast-crisis CML, and they may help unravel novel pathways responsible for the initiation and progression of leukaemia generally," Perrotti said.
The findings were presented at the 2007 annual meeting of the American Society of Haematology.