Biomol Ther (Seoul)  
Reduced Autophagy in 5-Fluorouracil Resistant Colon Cancer Cells
Cheng Wen Yao1, Kyoung Ah Kang1, Mei Jing Piao1, Yea Seong Ryu1, Pattage Madushan Dilhara Jayatissa Fernando1, Min Chang Oh1, Jeong Eon Park1, Kristina Shilnikova1, Soo- Young Na2, Seung Uk Jeong2, Sun-Jin Boo2,* and Jin Won Hyun1,*
1School of Medicine No.1 and Institute for Nuclear Science and Technology, Jeju National University, Jeju 63243, Republic of Korea
2School of Medicine No.2, Jeju National University, Jeju 63241, Republic of Korea
E-mail: (Boo SJ), (Hyun JW)
Tel: +82-64-754-8122 (Boo SJ), +82-64-754-3838 (Hyun JW)
Fax: +82-64-717-1131 (Boo SJ), +82-64-702-2687 (Hyun JW)
Received: March 28, 2016; Revised: July 15, 2016; Accepted: July 19, 2016; Published online: October 17, 2016.
© The Korean Society of Applied Pharmacology. All rights reserved.

We investigated the role of autophagy in SNUC5/5-FUR, 5-fluorouracil (5-FU) resistant SNUC5 colon cancer cells. SNUC5/5- FUR cells exhibited low level of autophagy, as determined by light microscopy, confocal microscopy, and flow cytometry following acridine orange staining, and the decreased level of GFP-LC3 puncta. In addition, expression of critical autophagic proteins such as Atg5, Beclin-1 and LC3-II and autophagic flux was diminished in SNUC5/5-FUR cells. Whereas production of reactive oxygen species (ROS) was significantly elevated in SNUC5/5-FUR cells, treatment with the ROS inhibitor N-acetyl cysteine further reduced the level of autophagy. Taken together, these results indicate that decreased autophagy is linked to 5-FU resistance in SNUC5 colon cancer cells.
Keywords: Autophagy, 5-Fluorouracil, SNUC5/5-FUR, Reactive oxygen species, Colon cancer

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