In a discovery that could be a ray of hope of millions of cancer patients,researchers have claimed that a drug for treating breast and lung cancers can be also used to heal other forms of the disease.
Analysing the outcomes of two preclinical studies,the researchers at UT Southwestern Medical Center found that the drug,Imetelstat,attacked not only the tumour cells but also the stem cells responsible for most of cancer’s growth.
“Because it attacks a mechanism that’s active in most cancers,it might prove to be widely useful,especially when combined with other therapies,” said Jerry Shay,co-author of both the papers.
The glioblastoma study,performed on a mice,is published in the latest issue of Clinical Cancer Research while the prostate cancer study,carried on humans,appeared in the International Journal of Cancer,ScienceBlog reported.
Focusing their research on tumor-initiating cells,Shay and his colleagues studied telomeres,bits of DNA that help control how many times a cell divides.
As long as the telomeres are longer than a certain minimum length,a cell keeps dividing. The cell shorten with each division and ultimately stops dividing once the DNA bits are whittled down to that minimum.
In cancer cells,however,an enzyme called telomerase keeps rebuilding the telomeres — so the cell never receives the cue to stop dividing — rendering them immortal.
The drug — Imetelstat — that is already in clinical trials as a potential treatment for breast and lung cancer,as well as for chronic lymphocytic leukaemia blocks telomerase.
In the glioblastoma study,it even crossed from the bloodstream into the brain.
Glioblastomas are the most common malignant brain tumours in adults. They are difficult to treat with drugs as blood vessels in the brain have tightly constructed walls that allow only a few substances to pass through.
During the study,researchers found that imetelstat blocked the action of telomerase in isolated tumor-initiating cells as well as the bulk of the tumour cells,eventually killing the cells.
Combining imetelstat with radiation and a standard chemotherapy drug rendered imetelstat even more effective.
When the researchers implanted human tumour-initiating cells into rodents,they found that imetelstat was able to enter brain tissue and inhibit telomerase activity.
In the prostate cancer study,the researchers isolated tumour-initiating cells from human prostate cancer cells. The cells showed significant telomerase activity.
Imetelstat blocked the enzyme’s activity,and telomeres shortened greatly.