Scientists from the University of São Paulo have identified an RNA molecule known as INXS that, although containing no instructions for the production of a protein, modulates the action of an important gene that impacts apoptosis.
According to Sergio Verjovski-Almeida, Ph.D., professor at the USP Chemistry Institute, INXS expression is generally diminished in cancer cells, and methods that are capable of stimulating the production of this noncoding RNA can be used to treat tumors.
“We were studying several protein-coding genes involved in cell death in search of evidence that one of them was regulated by intronic noncoding RNA. That was when we found the gene for BCL-X, which is located on chromosome 20,” he explained.
BCL-X is present in cells in two different forms: one that inhibits apoptosis and one that induces the process of cell death.
“In a healthy cell, there is a balance between the two BCL-X isoforms. Normally, there is already a smaller number of the pro-apoptotic form. However, in comparing tumor cells to nontumor cells, we observed that tumor cells contain even fewer of the pro-apoptotic form, as well as reduced levels of INXS. We suspect that one thing affects the other,” continued Dr. Verjovski-Almeida.
To confirm the hypothesis, the group silenced INXS expression in a normal cell lineage and the result, as expected, was an increase in the BCL-XL isoform.
The opposite occurred when the researchers artificially increased the amount of INXS using plasmid expression in a kidney cancer cell line, with the noncoding RNA being reduced.