Scientists identify critical tumour suppressor for cancer

Last Updated: Sunday, August 5, 2012 - 14:09

Washington: Scientist have found a protein that reduces the development of lymphoma or cancer of the lymph nodes, which they say will open up new therapeutic avenues to combat the disease.

The study by Scripps Research Institute scientists focuses on the role of this new tumour suppressor in lymphoma induced by Myc oncoproteins (the cancer-promoting products of Myc oncogenes). This circuit is apparently operational in all human tumours with MYC involvement, which is more than half of all human tumour types, the study has found.

"This opens a new therapeutic avenue to exploit for cancers with Myc involvement including relapsed metastatic tumours and refractory tumours, those that have not responded to treatment," study-leader and professor at the Department of Cancer Biology, John Cleveland said.

This protein impairs the development and maintenance of lymphoma, but is repressed during the initial stages of the disease, allowing for rapid tumour growth.

In the new study, the scientists focused on pre-cancerous and malignant Myc-expressing B cells, part of the immune system affected in human lymphoma.

The Myc family of oncoproteins (c-Myc, N-Myc, and L-Myc) regulate critical pathways that contribute to tumours; c-Myc expression, which is activated in human Burkitt lymphoma, is sufficient to induce the growth of several tumour types in mice.

The findings showed that Myc-directed repression of a protein called tristetraprolin (TTP/ZFP36) was important for both the development and maintenance of cancer.

The suppression of TTP is a hallmark of human cancers with MYC involvement, Cleveland noted.

The scientists` results showed that overriding this pathway by forced expression of TTP more than doubled the lifespan of Myc transgenic mice.

That re-introduction of TTP into Myc-driven lymphoma totally disabled these tumours, indicating an important therapeutic target, the researchers claim.

"Myc regulates the expression of select AU-binding proteins to control the destruction of certain mRNAs," Cleveland said, adding "our study strongly suggests that other AU-binding proteins may also, in fact, function as tumour suppressors in other cancers."

The findings of this study were published in the journal Cell.


First Published: Sunday, August 5, 2012 - 14:09

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