CD44/CD133-Positive Colorectal Cancer Stem Cells are Sensitive to Trifluridine Exposure

Kenta Tsunekuni,Kazuaki Matsuoka,Teiji Takechi,Hideshi Ishii,Takashi Kobunai,Ayumu Asai,Yuichiro Doki,Masamitsu Konno,Masaki Mori,Jun Koseki,Naotsugu Haraguchi

doi:10.1038/s41598-019-50968-6

Kenta Tsunekuni, Kazuaki Matsuoka + Show 9 more

Open Access

https://doi.org/10.1038/s41598-019-50968-6

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Abstract

Cancer stem cells (CSCs) are involved in metastatic colorectal cancer recurrence, but no effective therapy targeting these cells is currently available. Because trifluridine (FTD)/tipiracil therapy is used for refractory colorectal cancer, we sought to determine whether FTD is effective against CSC-like cells. CD44+CD133+ high-expressing and other populations of human DLD-1 colon cancer cells were separately isolated through fluorescence-activated cell sorting. The sphere-forming activity of each population and the anti-sphere-forming effects of FTD and fluorouracil (5-FU) on CD44+CD133+ cells were then measured. CD44+CD133+ DLD-1 cells formed substantially more spheres than other cells. Moreover, treating CD44+CD133+ DLD-1 cells with subtoxic concentrations of FTD (1 µM) inhibited sphere formation, and this was superior to the effect of subtoxic concentrations (1 µM) of 5-FU. The associated inhibition rates for FTD and 5-FU were 58.2% and 26.1%, respectively. Further, CD44+CD133+ DLD-1 cells expressed higher levels of thymidine kinase 1, which is responsible for FTD phosphorylation, than DLD-1 cells, and FTD was incorporated into the DNA of CD44+CD133+ DLD-1 cells. Thus, our data show that FTD treatment is effective against CSC-like cells and might be applied as CSC-targeting chemotherapy for tumor subtypes with high CD44 and CD133 expression.

Highlights

Cancer stem cells (CSCs) represent a subpopulation of cells that displays stem cell characteristics and this subset influences tumorigenesis[1]; further, CSCs exhibit diverse cancer-promoting properties such as self-renewal[2], chemoresistance[3], and metastatic potential[4,5]
The results indicate that CD44+ CD133+ populations exhibit the most stem cell-like properties compared to other populations
We showed that CD44+ CD133+ DLD-1 cells exhibit the highest sphere-forming activity compared to CD44− CD133−, CD44+ CD133−, and CD44− CD133+ DLD-1 cells, as reported previously for HCT-116 cells[19]

Summary

Introduction

Cancer stem cells (CSCs) represent a subpopulation of cells that displays stem cell characteristics and this subset influences tumorigenesis[1]; further, CSCs exhibit diverse cancer-promoting properties such as self-renewal[2], chemoresistance[3], and metastatic potential[4,5]. For the identification of CSCs, one of the first markers of stemness used was the transmembrane glycoprotein CD133, known as prominin-11,2, for which expression strongly predicts poorer prognosis; high CD133 levels are inversely correlated with the 5-year overall survival and disease-free survival rates in patients with cancers[6] including colorectal cancer (CRC). Another putative CSC marker is the cell-surface glycoprotein CD447, which was reported to be an adhesion molecule expressed in cancer stem-like cells[8]. We investigated whether this drug is effective against CD44- and CD133-highly-expressing (CD44+CD133+) CRC cells that possess CSC-like properties

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