New Treatment for Junk DNA Induced Cancers Discovered
Australian scientists from Sydney’s Garvan Institute of Medical Research, Brisbane’s Queensland Institute of Medical Research and American scientists from the University of California San Francisco report that junk DNA induced cancers can be reversed by shrinking the tumors. The results of their study are published in the September 2010 issue of the journal Nature Medicine.
Background of the Research on Junk DNA Induced Cancer Treatment:
In 1998, scientists Andrew Fire and Craig Mello discovered that some DNA molecules produce RNA molecules which in turn do not produce proteins, as is the case normally. Instead, they act as switches which turn on and off certain genes.
The 2006 Nobel Prize for medicine or physiology was awarded to these scientists for their discovery of this new role of RNA molecules. Such molecules were named non-coding RNAs and their role in causes and treatment of diseases was clear to the scientific community from the very beginning.
In genetics, genes are the chemical structures made up of DNA molecules. These are the instructions followed by the cells for their functioning. Proteins are the molecules which carry out the functions of cells. Certain DNA molecules are also found not to be involved in the encoding of proteins and perform no biological functions. They are referred as junk DNA.
In November 2006, researchers at the University of Iowa were the first to report that these DNA molecules were not junk per se. Their study found that these molecules could form certain sequential structures and give rise to a new class of genes called microRNAs.
These newly discovered genetic instructions at that time were not found to directly produce proteins but were rather instrumental in the regulation of protein production. In short, microRNAs were found to be non-coding RNAs. Their role in cancer was a foregone conclusion for researchers by that time.
Knowledge Gained from the Latest Research on Junk DNA Induced Cancer Treatment:
- The gene p53 is a primary gene in the suppression of tumors. The present study found that one particular microRNA namely the microRNA 380 disabled this gene.
- Any healthy cell turns cancerous the moment p53 gene gets either disabled or mutated (change in a gene’s chemical structure caused by external factors leading to modification in its functions).
- The p53 gene is found to get disabled by the over-production of microRNA 380.
Details of the Research:
The disabling of the gene was confirmed by the fact that the study was carried out on neuroblastoma. It is a form of nervous system cancer found in children where in 99 percent cases no mutation of the gene takes place. It leaves only one possibility for the occurrence of the cancer then, namely disabling of p53 gene.
Generally, microRNA 380 is not found in adult cells. Its production stops soon after the embryonic stage. Prior to this stage its presence is required for the very quick division of cells for birth. After this stage, this genetic material appears to get switched off. Turning on of this non-coding RNA and its abnormal production potentially causes the initiation of cancer.
In normal circumstances, when p53 gene is read, the RNA molecules produce p53 proteins. These proteins carry out the instructions of the gene to suppress tumors. But in a cancer patient’s body, the microRNA 380 gets attached to the RNA molecules of p53 genes and prevent them from producing the proteins. As the presence of p53 protein molecules decreases, the tumor cells begin to thrive.
As part of the research study, when the microRNA was blocked, production of p53 resumed, leading to the death of cancer cells and shrinking of the tumours. By turning off the switch in the cancerous cells, they can be reverted back to their normal healthy state.
Significance of the Research: Childhood neuroblastomas are the most common cancers in infancy. 650 new cases are reported of these cancers every year in the United States. In 50 percent of the cases, babies below the age of two are primarily affected.
A microRNA inhibitor can be simply injected twice a week to observe the benefits of this treatment in the affected patients clinically. Though further research is to be done, researchers are convinced that this study has opened up new possibilities for treating microRNA or junk DNA induced cancers like early childhood neuroblastomas.