Recently, it was demonstrated that treatment with adenosine triphosphate reduced the rate of sphere formation by glioma cells and that purinergic receptors are differentially expressed in spheres of tumour cells and adherent cells.
All other genes in the Notch pathway that were previously found to be differentially expressed in spheres were not differentially expressed among WT and KO tumors, except for Vegf, which was downregulated by a mean of 7.3-fold.
Secondary spheres could be cultured from dissociated recipient glands and spheres expressing eGFP (i.e. were donor derived) could be detected (Fig. 7A,B,C).
The number of spheres containing CD44v3highALDH1high 4T1 cells in each well and expressed as sphere forming units (SFU) as described previously [ 38].
Only 8% for the spheres that formed expressed TF, however in the presence of platelets the fraction of TF-expressing spheres increased to 22%.
Furthermore, our RNA-seq data indicate that smad2 is 25-fold more highly expressed at sphere stage than either smad3a/b.
54 An additional study of osteosarcoma, chondrosarcoma, and fibrosarcoma cell lines indicated that nestin mRNA is expressed in sphere-forming subpopulations; however, adherent subpopulations of the same cell lines were identified as nestin-negative.
Compared with wild-type (WT) spheres, the size of N2ICD-expressing spheres was significantly increased, whereas the size of MAML1dn-expressing spheres was significantly decreased (WT, 56±1.7 μm, n=90 spheres; N2ICD, 111±2.4 μm, n=215; MAML1dn, 41±0.5 μm, n=291; mean diameter ±S.E.M., P<0.0001; Figures 5a and b).
The chondrogenic differentiation capacity of MSC is evidenced by the formation of shiny cell-spheres expressing type II collagen in pellet cultures.
Our results clearly showed that the lower chamber cells in modified transwell system were easily forming spheres; furthermore, these spheres expressed high levels of stem cell markers (CD133/CD44/CD24/Oct-4/ESA) and exhibited chemoresistance, underwent epithelial-to-mesenchymal transition (EMT), and possessed the properties of self-renewal in vitro and tumorigenicity in vivo.
To determine if day seven spheres express pluripotency-associated markers, the expression of Oct4 and Sox2 was determined by RT-PCR.
