Washington, Apr 25 : Researchers at Ohio State University have successfully blocked tumour growth in an animal model by restoring two small molecules often lost in chronic leukaemia.
The animal study, using human chronic lymphocytic leukemia (CLL) cells, also showed that loss of the molecules called miR-15a and miR-16-1, affected 70 genes, most of which are involved in critical functions such as cell growth, death, proliferation and metabolism.
The two molecules are forms of microRNA, tiny molecules that cells use to help regulate the type and amount of proteins they make.
"These findings give us a signature of 70 deregulated genes that we believe finally explains at the molecular level how these two molecules contribute to CLL," said Carlo M. Croce, lead researcher and director of Ohio State's human cancer genetics program.
"The identification of these genes could also have important significance for the development of new therapeutic approaches for chronic leukemias," he added.
During the study, the scientists first injected mice with leukemia cells in which they had restored the two microRNAs.
They found that the tumour growth was completely suppressed in three of five animals and mice with leukemic cells that lacked the two molecules developed significant tumours.
"This clearly showed that these two microRNAs can suppress tumor development," said Muller Fabrri, co-author and researcher in Croce's laboratory.
A 2005 study conducted by the same team had shown that these two microRNAs target a gene called Bcl2, which normally helps cells survive by protecting them from accidental self-destruction.
The study was published recently in the Proceedings of the National Academy of Sciences.