A new research method has revealed that a number of cancer drugs may lead to tumor recurrence, illuminating a counterintuitive factor behind the disease that is expected to kill nearly 600,000 Americans in 2014.
Dr. Michele Markstein, a researcher at the University of Massachusetts Amherst and lead author of new study, said that the finding suggests that some FDA-approved chemotherapeutic drugs may induce a so-called hyper-proliferation of certain stem cells. "We discovered that several chemotherapeutics that stop fast growing tumors have the opposite effect on stem cells in the same animal, causing them to divide too rapidly,” she explained.
“This was a surprise, because it showed that the same drug could have opposite actions on cells in the same animal: Suppressing tumor growth on one cell population while initiating growth in another,” she added.
For the study, the researchers relied on a new Drosophila fly model that facilitates the stem cell experiments. According to Markstein, the methodology is a breakthrough in its own right, as it creates conditions that are "difficult-to-impossible" to achieve in petri dishes. Using this model, they tested a sample of 80 current chemotherapy drugs obtained from the National Cancer Institute.
"We systematically fed the FDA-approved drugs to the flies and found that 14 suppressed tumor growth in the intestine,” Markstein said in a press release. “This was a great result, validating the relevance of flies as a clinical model. It was also very interesting, however, that we found that half these tumor-suppressing drugs had the opposite effect on the non-tumor stem cells, causing them to over-proliferate.”
That said, this rapid division of stem cells does not necessarily spur new tumor development. But for a patient with the right genetic background, some of these drugs could significantly raise the risk of cancer recurrence.
According to World Cancer Research Fund International, there were an estimated 14.1 million cancer cases globally in 2012. Lung cancer, breast cancer, prostate cancer, and colorectal cancer accounted for nearly half of all diagnoses for both sexes. While the rate of diagnoses appears to be rising, the number of cancer deaths has decreased significantly over the past two decades.
The researchers are confident that the findings as well as the method will benefit future drug discovery and development. Not only is the finding of clinical interest,” Markstein said, “but with this study we used an emerging new non-traditional tool for assessing drugs using stem cells in the fruit fly gut."