A new research study published in the journal, Cancer Cell reported that scientists have discovered why some tumors respond less well to drug treatment as compared to others. Researchers have found that high levels of a specific molecule within cancer cells seem to block the effect of drugs such as Taxol, which are used to treat a number of cancers in their later stages. In the study, the researchers focused on a molecule called AURORA-A which is found at higher than normal levels in up to half of breast and bowel tumors, and in many other kinds of cancer. They genetically engineered cervical cancer cells with the gene for AURORA-A in order to increase levels of the molecule. They found that when treated with Taxol only about half as many engineered cells were killed by the drug as non-engineered cells.
In normal cell division, a cell can only divide if it has correctly shared out all its genes, ensuring each new cell receives a complete set. If there is a problem with the process of sharing out genes, an alarm will be triggered and the cell will not divide. However, cells with high amounts of AURORA-A seemed to over-ride the alarm and continue to divide, even when their genes were not correctly shared out. This ability to ignore the alarm could make them resistant to Taxol-type drugs. Lead researcher, Ashok Venkitaraman said that high amounts of AURORA-A seemed to make cancer cells less sensitive to treatment and a new test to look for the molecules in the tumor to predict how effective Taxol treatment is likely to be. The findings that are yet to be confirmed in cancer patients, raises the additional possibility that new drugs which inactivate the molecule could boost the response of cancer cells to treatment.