Cancer often strikes its final, fatal blow when a tumor spreads to other organs. A new study published online today in Science highlights this poorly understood process called metastasis. The researchers report that mutations in mitochondrial DNA may stimulate metastasis and can be reversed with drugs, at least in mice.
Mitochondria are tiny organelles the inherited from your mother used power plants of the cell. They have their own DNA, called mitochondrial DNA. It is ten years, cancer researchers noticed that mtDNA in tumor cells tends to be riddled with mutations - much more than in normal tissues. (This is partly because mtDNA are not packed in protein, which makes it more vulnerable to damage.) Some researchers believe mtDNA can cause tumors. But others suggest that the mutations are simply a byproduct of cancer; they note that people with mitochondrial diseases are not particularly susceptible to cancer, and the risk of cancer are not inherited maternally, as expected for a disease related to mitochondria.
To explore the role of mtDNA mutations in cancer, Jun -Ichi Hayashi's group at the University of Tsukuba in Japan and colleagues swapped the mtDNA of two types of tumor cells mice: one that tends to metastasize and another that does not. When they injected these hybrid cells under the skin of mice, the cells grew into tumors that eventually spread to the lungs. The mice that received the mtDNA from metastatic cells had significantly more lung tumors than mice that had mtDNA from metastases less prone to cells, suggesting that mtDNA was indeed the culprit. However, mtDNA does not seem to be involved in the formation of the primary tumor: When the group exchanged mtDNA from metastatic cells in normal cells, it did not cause these tumors to form
The metastatic mtDNA appeared to do his dirty business. with two mutations that caused the mitochondria to overproduce reactive oxygen species is known, which are molecules of DNA damaging toxic. When the researchers put a drug that sops up these molecules into the drinking water of mice that received metastatic cells under the skin, they almost not developed lung tumors.
The document is "a technical tour of strength," said Robert Taylor researcher mitochondria of Newcastle University in the UK, and the fact that antioxidants suppressed metastasis warrants further study, he said . Kornelia Polyak of Dana-Farber cancer Institute in Boston warns, however, that the antioxidants in clinical trials testing cancer prevention have had mixed results and that giving antioxidants to someone on chemotherapy could interfere with treatment.
related site
- Information about metastatic cancer
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