Measuring Glycogen Usage in Insulin-Treated Ishikawa Cells
Faculty Mentor Information
Dr. Jennifer Chase, Northwest Nazarene University
Presentation Date
7-16-2026
Abstract
In cancer cells, glycogen is believed to be a source of glucose to meet high metabolic demands. Endometrial cancer cells, such as the Ishikawa EC cell line, have been shown to proliferate more rapidly with insulin treatment. We hypothesized insulin would stimulate glycogen synthesis in serum-starved Ishikawa cells. We developed a 96-well plate-based assay for glycogen synthesis which measures the glucose released from 25K cells in a Hexokinase/G6PDH-coupled assay producing NADPH in proportion to stored glycogen. In 96-well plates, the cells were pretreated for 24 hours in glucose-free media, then treated an additional 24 hours in glucose-free media containing varying levels of insulin. Our results indicated that in insulin-treated samples, glycogen levels decreased. After 24 hours, glycogen level on average decreased from 144 + 6 to 102 + 16 ng, with no difference between insulin treatments, ranging from 50 ng/ml to 50 ug/ml. Our study is underpowered, but indicates glucose is used by cells too quickly for storage under these conditions. Additionally, glycogen is shown to be used at a rate of 0.029 nmol/min/mg protein even with glucose present. These cancer cells are using stored glycogen to supply glucose needs in a way unaffected by insulin.
Measuring Glycogen Usage in Insulin-Treated Ishikawa Cells
In cancer cells, glycogen is believed to be a source of glucose to meet high metabolic demands. Endometrial cancer cells, such as the Ishikawa EC cell line, have been shown to proliferate more rapidly with insulin treatment. We hypothesized insulin would stimulate glycogen synthesis in serum-starved Ishikawa cells. We developed a 96-well plate-based assay for glycogen synthesis which measures the glucose released from 25K cells in a Hexokinase/G6PDH-coupled assay producing NADPH in proportion to stored glycogen. In 96-well plates, the cells were pretreated for 24 hours in glucose-free media, then treated an additional 24 hours in glucose-free media containing varying levels of insulin. Our results indicated that in insulin-treated samples, glycogen levels decreased. After 24 hours, glycogen level on average decreased from 144 + 6 to 102 + 16 ng, with no difference between insulin treatments, ranging from 50 ng/ml to 50 ug/ml. Our study is underpowered, but indicates glucose is used by cells too quickly for storage under these conditions. Additionally, glycogen is shown to be used at a rate of 0.029 nmol/min/mg protein even with glucose present. These cancer cells are using stored glycogen to supply glucose needs in a way unaffected by insulin.