Deanna Csomo McCool | August 20, 2017
Colorectal cancer patients may benefit by avoiding sweets for three days before chemotherapy and by taking a common antimalaria drug, according to new research by biochemistry doctoral student Monica Schroll.
Schroll, Amanda Hummon, associate professor of chemistry and biochemistry and member of the Harper Cancer Research Institute, along with two others studied a two-pronged method of weakening colorectal cancer cells to improve the effectiveness of chemotherapy, then measured the mass of different proteins in the cells using mass spectrometry. Tumor suppressor proteins increased their response after this protocol, making the cancer cells more sensitive to chemotherapy. The result of their research, “Glucose Restriction Combined with Autophagy Inhibition in HCT 116 Spheroids Decreases Cell Clonogenicity and Viability Regulated by Tumor Suppressor Genes” was published last month in Journal of Proteome Research.
There’s no oxygen at the center of a tumor, so cancer cells must rely on anerobic respiration, the type of respiration that doesn’t use oxygen, to flourish. Glucose, therefore, is a cancer cell’s primary food for metabolism. Starve the cells of glucose for 72 hours—which Schroll did by removing it from cell culture media before harvesting the cells—and a process called autophagy is activated. During autophagy, cells maintain their metabolism by recycling their cellular components “like getting rid of all the clutter in your house,” Hummon described.
Autophagy can be helpful, but within a cancer cell, the process keeps the cells alive even when glucose is restricted. “There’s a lot of random debris floating around in the cell and if you keep on feeding cells, they’ll take the extra nutrients and fill themselves up,” Hummon said. But the antimalarial drug Chloroquine halts late-stage autophagy and decreases the viability of cancer cells. Starving the cells plus blocking autophagy with the drug reduced the survival of the colorectal cells when subjected to chemotherapy treatments in Scroll’s lab samples.