MicroRNA Exploited to Combat Cancer

By blocking the function of microRNAs, researchers have significantly decreased the size of a cancerous tumor in a mouse model.

The investigators involved in the project were from the Queensland Institute of Medical Research (QIMR; Herston, Australia), the Garvan Institute of Medical Research (Sidney, NSW, Australia), and the University of California San Francisco (UCSF; USA). "MicroRNAs originate from part of our DNA that has long been thought of as junk DNA. Much is still unknown but we know they can interfere with the functioning of genes and can control the production of proteins in the body,” said QIMR researcher Dr. Susan Woods.

Neuroblastoma is a cancer of the sympathetic nervous system, a nerve network throughout the body that delivers messages from the brain. Neuroblastoma is a solid, malignant tumor that presents as a lump or mass in the abdomen or around the spinal cord in the chest, neck, or pelvis. Neuroblastoma is frequently present at birth, but is most often diagnosed much later when the child begins to show symptoms of the disease.

"A lot of cancer research has focused on a protein called p53 that acts as a natural defense again cancer. Without p53, a normal cell can multiply out of control--in other words become cancerous. We chose to study a particular type of cancer called neuroblastoma, which is a childhood cancer of the nervous system. We found that these cancers disable p53 by over-producing the microRNA that we study. This results in a reduction in the amount of protection against cancerous changes in that cell--leading to the growth of tumors. However, when we blocked the microRNA, p53 production resumed, the cancer cells died and the tumors became much smaller,” commented Dr. Woods.

MicroRNA inhibitors have been readily available for use in the laboratory for approximately the last five years. "What is really exciting about this research is it is the first time that anyone has blocked the growth of a primary tumor by the simple delivery of a microRNA inhibitor. While this finding is at an early research stage, our results indicate that this microRNA is a potential therapeutic target for future treatment of early childhood neuroblastomas and other microRNA-induced cancers,” concluded Dr. Woods.

The study was published September 28, 2010, in the journal Nature Medicine.

Related Links:
Queensland Institute of Medical Research
Garvan Institute of Medical Research
University of California-San Francisco