ABSTRACT
To investigate whether Portulaca oleracea extract affects tumor formation in colon cancer stem cells and its chemotherapy sensitivity. In addition, to analyze associated genetic changes within the Notch signal transduction pathway. Serum-free cultures of colon cancer cells (HT-29) and HT-29 cancer stem cells were treated with the chemotherapeutic drug 5-fluorouracil to assess sensitivity. Injections of the stem cells were also given to BALB/c mice to confirm tumor growth and note its characteristics. In addition, the effect of different concentrations of P. oleracea extract was tested on the growth of HT-29 colon cancer cells and HT-29 cancer stem cells, as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The effects of P. oleracea extract on the expression of ß-catenin, Notch1, and Notch2 in the HT-29 cells were studied using reverse transcription polymerase chain reaction and Western blotting. The tumor volume of the HT29 cells was two times larger than that of HT29 cancer stem cells. Treatment with P. oleracea extract inhibited the proliferation of both HT-29 cancer cells and HT-29 cancer stem cells at doses from 0.07 to 2.25 µg/mL. Apoptosis of HT-29 cancer cells and HT-29 cancer stem cells was assessed by flow cytometry; it was enhanced by the addition of P. oleracea extract. Finally, treatment with P. oleracea extract significantly downregulated the expression of the Notch1 and ß-catenin genes in both cell types. The results of this study show that P. oleracea extract inhibits the growth of colon cancer stem cells in a dose-dependent manner. Furthermore, it inhibits the expression of the Notch1 and ß-catenin genes. Taken together, this suggests that it may elicit its effects through regulatory and target genes that mediate the Notch signal transduction pathway.
Subject(s)
Carcinogenesis/drug effects , Colonic Neoplasms/drug therapy , Plant Extracts/administration & dosage , Receptor, Notch1/genetics , beta Catenin/genetics , Animals , Apoptosis/drug effects , Carcinogenesis/genetics , Cell Proliferation/drug effects , Colonic Neoplasms/genetics , Colonic Neoplasms/pathology , Gene Expression Regulation, Neoplastic , HT29 Cells , Humans , Mice , Neoplastic Stem Cells/drug effects , Neoplastic Stem Cells/pathology , Plant Extracts/chemistry , Portulaca/chemistry , Signal Transduction , Xenograft Model Antitumor AssaysABSTRACT
Studies show that the Notch signal transduction pathway involves in the regulation and control of cell proliferation,differentiation and apoptosis.Aberrant Notch signaling transduction pathway can induce breast cancer in transgenic mice.High expressions of either Notch receptors or their ligands have been linked to poor prognosis in patients with breast cancer.Inhibition of Notch signal transduction pathway may be beneficial for breast cancer treatment.
ABSTRACT
Objective:To research the effect of Liuwei Dihuang decoction and its decomposed recipes on gene expression related to thymocyte differentiation in normal mice and SAMP8.Methods:The expression of Notch1,Presenilin1,Presenilin2,HES1 mRNA was detected by quantitative real-time fluorescence PCR assay.Results:After oral administation of Liuwei Dihuang decoction(5,10,20 g/kg),the expressions of Presenilin2 and HES1 gene in thymocytes of normal mice were increased.After oral administation of Liuwei Dihuang decoction(10 g/kg)and SB,SX,the expressions of Presenilin2 and HES1 in thymocytes of normal mice were decreased.Conclusion:It is suggested that Liuwei Dihuang Decoction can increase the Notch signal intensity in the normal mice thymocytes and decrease that in SAMP8,which is immuno-senescenced mice.
