Background
Colorectal cancer (
CRC
) is the third most commonly diagnosed cancer in males and the second in females worldwide in 2012. In the past 20 years, strong evidence suggests that cancer stem cells are the main culprit of cancer metastasis, chemotherapy resistance, and relapse.
Methods
To further understand the unique biological properties of cancer stem cells and uncover novel molecular targets to eradicate them, we first established a panel of patient‐derived xenograft (
PDX
) tumor models using tumors surgically removed from human colorectal cancer patients. We then isolated
CRC
cancer stem cells based on their
ALDH
activity using fluorescent‐activated cell sorting (
FACS
) and characterized their metabolic properties.
Results
Interestingly, we found that the
CRC
cancer stem cells (ie,
CRC
cells with higher
ALDH
activity, or
ALDH
+) express higher level of antioxidant genes and have lower level of reactive oxygen species (
ROS
) than non‐
CRC
cancer stem cells (ie,
CRC
cells with lower
ALDH
activity, or ALDH−). The
CRC
cancer stem cells also possess more mitochondria mass and show higher mitochondrial activity. More intriguingly, we observed higher
AMP
‐activated protein kinase (
AMPK
) activities in these
CRC
cancer stem cells. Inhibition of the
AMPK
activity using 2
AMPK
inhibitors, Compound C and Iodotubercidin, preferentially induces cell death in
CRC
cancer stem cells.
Conclusion
We propose that
AMPK
inhibitors may help to eradicate the
CRC
cancer stem cells and prevent the relapse of
CRC
s.