A new study has revealed that a protein called STAT3 has a major role to play in the conversion of normal cells into cancerous cells.
Led by Dr. David E. Levy, a professor of pathology and microbiology at NYU Langone Medical Centre, the study found that STAT3 not only plays a part in the cell nucleus regulating gene expression, but is also present in mitochondria and regulates the activity of the electron transport chain in tumour cells.
Mitochondria are the basic energy-producing organelles of the cell, and are known to be critical for tumour cell metabolism.
"These results open the possibility that inhibiting the mitochondrial function of STAT3 could be a promising cancer therapy in the future.
By knowing this mitrochondrial function is critical, it may be possible to design therapeutic strategies that specifically target this function while sparing the other functions of the protein, such as its ability to turn genes on. Therefore, we would hope that inhibitors could be developed that would be highly specific for cancer cells," added Levy.
STAT3, which stands for "signal transducer and activators of transcription", is a protein that was discovered as a regulator of gene expression.
Its only function was thought to be to turn genes on in the cell nucleus, particularly when the cells have been exposed to events that require an immune response.
However, it was found to mediate many critical steps in the response to infection.
The researchers in the current study have been studying STAT3 since the mid 1990s, when they first cloned its gene.
The current results were obtained from experiments that examined tumours caused by the Ras oncogene, which causes many human cancers.
"Future experiments will need to determine if a similar mitochondrial role for STAT3 is critical for other types of cancer as well. We'll also need a better understanding of the biochemical basis for the function of STAT3. For instance, we are trying to find out what STAT3 does in mitochondria, what enzymes and processes it regulates and how these processes differ in tumors compared to normal cells," said Levy.
The study has been published in the journal Science.