Background and Objective:CD133-positive colon cancer stem like cells (CSLCs) are resistant to the conventional cytotoxic drug 5-fluorouracil (5-FU).Wnt signaling pathway plays important roles in colon cancer carcinoge...Background and Objective:CD133-positive colon cancer stem like cells (CSLCs) are resistant to the conventional cytotoxic drug 5-fluorouracil (5-FU).Wnt signaling pathway plays important roles in colon cancer carcinogenesis and metastasis, and regulates the self-renewal capacity of CSLCs.In the present study, we explored the impact of 5-FU on Wnt signaling pathway of CD133-positive colon CSLCs, and the relation between Wnt signaling pathway and drug resistance of CD133-positive colon CSLCs.Methods:Magnetic activation cell separation was used to collect CD133-positive cells from colon cancer cell line DLD1, which was transfected with luciferase reporter for Wnt signaling activity.The activity of Wnt signaling pathway was compared between CD133-positive and CD133-negative cells.After the treatment with 1 μg/mL of 5-FU, the cell proliferation rates of DLD1 cells, CD133-positive cells, and CD133-negative cells were compared.After the treatment with 1 μg/mL and 10 μg/mL of 5-FU for 48 h, Wnt activity was compared between CD133-positive and CD133-negative cells.The expression of CD133 and cell apoptosis of CD133-positive cells was detected after exposure to 50 ng/mL of dickkopf (DKK)-1, a Wnt pathway inhibitor.Results:After the treatment with 5-FU, the cell proliferation rate of CD133-positive cells was higher than that of CD133-negative cells and the sensitivity of CD133-positive cells to 5-FU decreased.Wnt activity was higher in CD133-positive cells than in CD133-negative cells [(46.3±0.3)% vs.(33.9±2.7)%, P=0.009].After the treatment with 1 μg/mL and 10 μg/mL of 5-FU, Wnt activity of CD133-positive cells was (90.1±10.0)% (P=0.012) and (52.9±2.5)% (P=0.047), respectively, whereas that of CD133-negative cells was (35.5±3.3)% (P=0.434) and (26.5±0.4)% (P=0.046), respectively.CD133 expression in CD133-positive cells decreased from (87.2±5.3)% to (60.6±3.1)% (P=0.022) after treatment with DKK-1, whereas the cell apoptosis rate increased from (11.8±0.2)% to (28.3±0.6)% (P=0.013).Conclusions:Wnt activity is higher in CD133-positive DLD1 cells than in CD133-negative DLD1 cells.5-FU can upregulate Wnt activity of CD133-positive colon CSLCs.Blocking Wnt activity may reverse drug sensitivity of CD133-positive cells to 5-FU.展开更多
Carcinogenesis is a multistep process that requires the accumulation of various genetic and epigenetic aberrations to drive the progressive malignant transformation of normal human cells.Two major hallmarks of carcino...Carcinogenesis is a multistep process that requires the accumulation of various genetic and epigenetic aberrations to drive the progressive malignant transformation of normal human cells.Two major hallmarks of carcinogenesis that have been described are angiogenesis and the stem cell characteristic of limitless replicative potential.These properties have been targeted over the past decade in the development of therapeutic treatments for colorectal cancer(CRC),one of the most commonly diagnosed and lethal cancers worldwide.The treatment of solid tumor cancers such as CRC has been challenging due to the heterogeneity of the tumor itself and the chemoresistance of the malignant cells.Furthermore,the same microenvironment that maintains the pool of intestinal stem cells that contribute to the continuous renewal of the intestinal epithelia also provides the necessary conditions for proliferative growth of cancer stem-like cells.These cancer stem-like cells are responsible for the resistance to therapy and cancer recurrence,though they represent less than 2.5%of the tumor mass.The stromal environment surrounding the tumor cells,referred to as the tumor niche,also supports angiogenesis,which supplies the oxygen and nutrients needed for tumor development.Anti-angiogenic therapy,such as with bevacizumab,a monoclonal antibody against vascular-endothelial growth factor,significantly prolongs the survival of metastatic CRC patients.However,such treatments are not completely curative,and a large proportion of patient tumors retain chemoresistance or show recurrence.This article reviews the current knowledge regarding the molecular phenotype of CRC cancer cells,as well as discusses the mechanisms contributing to their maintenance.Future personalized therapeutic approaches that are based on the interaction of the carcinogenic hallmarks,namely angiogenic and proliferative attributes,could improve survival and decrease adverse effects induced by unnecessary chemotherapy.展开更多
基金Guangdong Natural Science Fund Committee (No.9451008901002630)
文摘Background and Objective:CD133-positive colon cancer stem like cells (CSLCs) are resistant to the conventional cytotoxic drug 5-fluorouracil (5-FU).Wnt signaling pathway plays important roles in colon cancer carcinogenesis and metastasis, and regulates the self-renewal capacity of CSLCs.In the present study, we explored the impact of 5-FU on Wnt signaling pathway of CD133-positive colon CSLCs, and the relation between Wnt signaling pathway and drug resistance of CD133-positive colon CSLCs.Methods:Magnetic activation cell separation was used to collect CD133-positive cells from colon cancer cell line DLD1, which was transfected with luciferase reporter for Wnt signaling activity.The activity of Wnt signaling pathway was compared between CD133-positive and CD133-negative cells.After the treatment with 1 μg/mL of 5-FU, the cell proliferation rates of DLD1 cells, CD133-positive cells, and CD133-negative cells were compared.After the treatment with 1 μg/mL and 10 μg/mL of 5-FU for 48 h, Wnt activity was compared between CD133-positive and CD133-negative cells.The expression of CD133 and cell apoptosis of CD133-positive cells was detected after exposure to 50 ng/mL of dickkopf (DKK)-1, a Wnt pathway inhibitor.Results:After the treatment with 5-FU, the cell proliferation rate of CD133-positive cells was higher than that of CD133-negative cells and the sensitivity of CD133-positive cells to 5-FU decreased.Wnt activity was higher in CD133-positive cells than in CD133-negative cells [(46.3±0.3)% vs.(33.9±2.7)%, P=0.009].After the treatment with 1 μg/mL and 10 μg/mL of 5-FU, Wnt activity of CD133-positive cells was (90.1±10.0)% (P=0.012) and (52.9±2.5)% (P=0.047), respectively, whereas that of CD133-negative cells was (35.5±3.3)% (P=0.434) and (26.5±0.4)% (P=0.046), respectively.CD133 expression in CD133-positive cells decreased from (87.2±5.3)% to (60.6±3.1)% (P=0.022) after treatment with DKK-1, whereas the cell apoptosis rate increased from (11.8±0.2)% to (28.3±0.6)% (P=0.013).Conclusions:Wnt activity is higher in CD133-positive DLD1 cells than in CD133-negative DLD1 cells.5-FU can upregulate Wnt activity of CD133-positive colon CSLCs.Blocking Wnt activity may reverse drug sensitivity of CD133-positive cells to 5-FU.
基金Supported by Grants from the University of Limoges,Limoges University Hospital,La Ligue Contre le Cancer and the Région Limousin,which was given financial by the ComitéOrientation Recherche Cancer(to Perraud A,Christou N and Akil H)
文摘Carcinogenesis is a multistep process that requires the accumulation of various genetic and epigenetic aberrations to drive the progressive malignant transformation of normal human cells.Two major hallmarks of carcinogenesis that have been described are angiogenesis and the stem cell characteristic of limitless replicative potential.These properties have been targeted over the past decade in the development of therapeutic treatments for colorectal cancer(CRC),one of the most commonly diagnosed and lethal cancers worldwide.The treatment of solid tumor cancers such as CRC has been challenging due to the heterogeneity of the tumor itself and the chemoresistance of the malignant cells.Furthermore,the same microenvironment that maintains the pool of intestinal stem cells that contribute to the continuous renewal of the intestinal epithelia also provides the necessary conditions for proliferative growth of cancer stem-like cells.These cancer stem-like cells are responsible for the resistance to therapy and cancer recurrence,though they represent less than 2.5%of the tumor mass.The stromal environment surrounding the tumor cells,referred to as the tumor niche,also supports angiogenesis,which supplies the oxygen and nutrients needed for tumor development.Anti-angiogenic therapy,such as with bevacizumab,a monoclonal antibody against vascular-endothelial growth factor,significantly prolongs the survival of metastatic CRC patients.However,such treatments are not completely curative,and a large proportion of patient tumors retain chemoresistance or show recurrence.This article reviews the current knowledge regarding the molecular phenotype of CRC cancer cells,as well as discusses the mechanisms contributing to their maintenance.Future personalized therapeutic approaches that are based on the interaction of the carcinogenic hallmarks,namely angiogenic and proliferative attributes,could improve survival and decrease adverse effects induced by unnecessary chemotherapy.
