Cancers Hijack Body’s Defences To Grow And Spread
Cancer Research UK scientists have discovered how two genes can ‘hijack’ control of part of the body’s defences against cancer, helping them grow and spread. Their research was published in Developmental Cell(1) yesterday (Tuesday).
Part of the body’s defence system is controlled by a gene called Tumour Necrosis Factor (TNF) that can stop cancers from developing by killing them. But this same response has also been shown to help promote the growth of cancers.
For the first time, scientists at the Cancer Research UK Beatson Institute in Glasgow have shown how TNF turns to the ‘dark side’, helping some cancers to grow and move to new parts of the body. They found that the TNF response is hijacked by two genes linked to cancer.
The two genes are a tumour suppressor gene, that promotes tumour growth when deleted, and a tumour promoter gene that can turn cells cancerous when activated.
In their study, using fruit flies (Drosophila melanogaster), they found that cells which lack a tumour suppressor gene and turn cancerous are targeted and killed by the TNF controlled response. But, if the tumour promoter is also activated, cancer cells are not only able to escape the TNF’s death signal but also produce a signal to help them spread and grow. Read more
Scientists Find Key To Gene That Promotes Cancer Metastasis
The molecular machinery that switches on a gene known to cause breast cancer to spread and invade other organs has been identified by an international team led by scientists at The University of Texas M. D. Anderson Cancer Center. The paper was published Sunday in Nature Cell Biology’s advanced online publication.
The discovery provides a target-rich environment for development of drugs to thwart expression of the RhoA gene, according to Hui-Kuan Lin, Ph.D., the paper’s senior author and an assistant professor in M. D. Anderson’s Department of Molecular and Cellular Oncology. RhoA overexpression has been implicated in cancer metastasis.
“There are four components to this complex, which starts RhoA expression by transcribing the gene, and we found that all of them are important to metastasis,” Lin said. “Knock down any one of the four, and you can stop breast cancer metastasis by preventing RhoA expression.”
Researchers built their case with a series of laboratory experiments on cell lines, followed by confirmation in a mouse model of breast cancer metastasis and then analysis of 64 prostate cancer tumors that showed overexpression of RhoA or three of its transcription complex components were strongly correlated with metastatic disease.
Transcription is the first step on a gene’s path to expressing its protein. Transcription factors bind to the promoter region of the gene, causing a copy of RNA to be made from the DNA of the gene. The RNA is then translated into the corresponding protein. Read more