ABSTRACT
CONTEXT: The Notch signaling pathway is one of the most important pathways during normal development and implicated in self-renewal of adult stem cells and differentiation of progenitor cells. Abnormal expression of Notch receptors has been associated with many epithelial metaplastic and neoplastic lesions. OBJECTIVE-MATERIALS AND METHODS: In this particular study, it was determined the relative gene expression of Notch receptors after knockdown experiments in colon cancer stem cells (CSCs) and the gene expression changes in stemness transcription factors (Oct4, Sox2, Nanog), as well in dipeptidylpeptidase-4, CD44 antigen, Met proto-oncogene and in Metnase transposase. RESULTS: In control CSCs Notch-2 had the higher expression, followed by Notch-1, Notch-3. Notch-4 demonstrated the lower gene expression among the receptors. The suppression of Notch-1 led to increased expression of Oct4 and Sox2, but in decreased gene expression of cMET, Setmar and CD44. The CD26 expression remained unchanged. The knockdown of Notch-2 led to decreased expression of all transcription factors. Notch-3 down regulation caused increased Oct4 gene expression, but decreased levels for the rest of the genes. Finally, the suppression of Notch-4 had the same effect as in receptor Notch-3. DISCUSSION AND CONCLUSION: The above experimental data suggest the possible interaction between the four different receptors of Notch signaling pathway. The expression of CD26, cMET and N-methyltransferase Setmar was also changed. Finally, the stemness phenotype was changed in a different way each time, according to the receptor that was down regulated. All Notch receptors and particularly Notch-2 seem to play an important role in cancer stem cells.
Subject(s)
Cell Differentiation/genetics , Colonic Neoplasms/metabolism , Histone-Lysine N-Methyltransferase/metabolism , Proto-Oncogene Proteins c-met/metabolism , Receptors, Notch/biosynthesis , Colonic Neoplasms/genetics , Colonic Neoplasms/pathology , Dipeptidyl Peptidase 4/metabolism , Gene Expression Regulation, Developmental , Gene Expression Regulation, Neoplastic , Humans , Hyaluronan Receptors/metabolism , Neoplastic Stem Cells/metabolism , Proto-Oncogene Mas , Receptors, Notch/genetics , Receptors, Notch/metabolism , Signal TransductionABSTRACT
There is much evidence about importance of angiogenesis in development and progression of solid tumors. The role of angiogenesis, as an indicator of higher malignant potential in non-Hodgkin's lymphoma, is not clear at the moment. Morphometric characteristics of microvessels in lymph node sections, in previously untreated patients with small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) and diffuse large B-cell lymphoma (DLBCL), were studied and relationship between angiogenesis and histological malignancy grade of NHL was also evaluated. Lymph node biopsies samples of 30 newly diagnosed patients with SLL/CLL (n=30) and DLBCL (n=30) were studied. All samples were fixed in 10% buffered formalin solution and embedded in paraffin. Microvessels were visualized by immunohistochemical staining for anti F-8 antibody. In the area showing the most intense vascularization (i.e. the "hot spot"), microvessel density (MVD), total vascular area (TVA), as well as the size related parameters were estimated, by using image analysis program "analysSIS'. Number and size-related microvessels angiogenic morphometric parameters were statistically higher in group with DLBCL compared with SLL/CLL: MVD (p = 0.002), TVA (p < 0.0001), area (p < 0.0001), perimeter (p < 0.0001), minor axis length (p < 0.0001) and major axis length (p < 0.0001). It is to be noted that positive correlation existed between TVA and MVD in DLBCL and SLL/CLL. The present study supports the view that angiogenesis correlate with histological grade of NHL.
