Cancer breakthrough as US scientists find a way to switch mutant cells back to normal
Scientists in the United States believe they have found a way to reverse the process which causes increased cell replication and tumour growth, offering hope for a new breakthrough treatment which could potentially eliminate the need for harsh chemotherapy, radiotherapy and even surgery.
For the first time the team at Florida's Mayo Clinic, led by Professor Panos Anastasiadis, of the Department for Cancer Biology, restored aggressive breast, lung and bladder cancer cells to normal, benign cells. The breakthrough, published in journal Nature Cell Biology, was achieved by reintroducing a naturally-occurring microprocessor, produced by healthy cells, that regulates normal cell replication.
Microprocessors, known as microRNAs, regulate healthy cell replication, and operate by sending chemical signals via the production of a protein, PLEKHA7, to the cell adhesion structure or glue that holds cells together. In a healthy person, cells divide and replicate as part of the process of healthy tissue replacement, however, PLEKHA7 instructs the cells when to break the cell bonds and thereby halt the process of cell replication.
In cancer patients, and for reasons not yet fully understood, this process no longer works. So cancer develops when microRNAs stop working properly - leading to excessive cell replication, cell mutation and abnormal growths or tumours.
'Switching off' cancer
Scientists found that the removal of microRNAs led to abnormal cell production and cancer cell development but crucially they found the process also works in reverse. MicroRNAs are small molecules that could, in theory, be delivered to the site of a tumour via injection - effectively switching the cancer off.
While this method has so far only been tested on human cells in a laboratory, researchers are hopeful that in the future the technique could be used directly target tumours without the need for invasive surgery or harsh chemical or ionising radiation treatments, which themselves carry separate risks and can impact on patient outcome. It is also hoped that the findings will enable doctors to identify the potential for cancer developing at an earlier stage.
Biologists have been puzzled for decades as to why cells do not naturally prevent this abnormal cell replication and go on to become tumorigeneric.
Speaking about the discovery on the Mayo Clinic's YouTube channel, Prof. Anastasiadis says: "It represents an unexpected new biology that provides the code, the software for turning off cancer."
He adds: "We have now done this in very aggressive human cell lines from breast and bladder cancer. These cells are already missing PLEKHA7. Restoring either PLEKHA7 levels, or the levels of miRNAs in these cells turns them back to a benign state."
Prof. Anastasiadis says his team are now concentrating on possible treatment delivery options.
Henry Scowcroft, Cancer Research UK’s senior science information manager, says of the discovery: "This important study solves a long-standing biological mystery, but we mustn’t get ahead of ourselves.
"There’s a long way to go before we know whether these findings, in cells grown in a laboratory, will help treat people with cancer. But it’s a significant step forward in understanding how certain cells in our body know when to grow, and when to stop. Understanding these key concepts is crucial to help continue the encouraging progress against cancer we’ve seen in recent years".
John Hall, Chief Medical officer at General & Medical says of the discovery: “It is certainly a breakthrough in our knowledge of cell division but it should be stressed that this has only been done in vitro in the laboratory. It will likely require many years of work before techniques have been developed to employ it in vivo - in the human body. As always it will be necessary to determine the effectiveness of the technique in preventing malignant cell division in the affected patient and the absence of side effects.”
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