A hypoxic niche to protect human colon carcinoma stem cells from chemotherapy.

e14096 Background: Recent evidence suggests that a subpopulation of tumorigenic CD133+ cells from human colon carcinoma be termed as colon cancer stem cells (cCSCs). Our earlier study demonstrated that most of human cCSCs located in hypoxic niche, and the hypoxic human cCSCs resisted radiotherapy to some extent. However, little was known whether hypoxia niche could protect cCSCs from chemotherapy in vivo. Methods: Each of 23 fresh samples of human colon adenocarcinoma was transplanted into nude mice. The tumor-bearing mice derived from five primary tumors were randomized to 4 groups when xenografts reached 100mm3~250mm3: A: saline, B: 5-FU, C: oxaliplatin, and D: oxaliplatin plus 5-FU. After 2 weeks’ treatment, the percentages of hypoxic CD133+ and CD133- population were quantified by flow-cytometry marked by pimonidazole (PIM). CD133+ and CD133- cells were sorted and detected for ki67 and PIM via immunofluorescence double staining. Results: Mice xenografts were successfully established from 17 of 23 samp...