At a plating density of 1.5 cells/µl, CD133 expressing cells exhibited increased sphere formation (Fig. 6A).
LA-N-5 spheres were further studied and showed a verapamil-sensitive side population, relative resistance to doxorubicin, and CD133+ cells showed increased sphere formation and tumorigenicity.
Increased sphere-formation in the doxorubicin-cultured SP may reflect the doxorubicin-induced increase in cells expressing both CD133 and ABCG2, possibly cells with higher sphere-forming ability.
Consistent with the increased expression of self-renewal genes, SP and ALDHhigh subpopulations displayed significantly increased sphere-forming activities compared with non-SP and ALDHlow cells, respectively.
These observations suggest that remnant living cells in late-stage tumors exhibit increased sphere-forming capacity, which is one of the CSC characteristics.
Isolated nestin-positive cells showed increased sphere-forming capacity and sphere size.
Furthermore, the recovery of the activity concentrations within the physical boundaries of the spheres increased with increasing sphere volume.
The debonding stresses increased with decreasing sphere diameter, whereas the length to diameter ratio of the resulting matrix cracks increased with increasing sphere diameter.
With the increased nanoporous sphere ratio, the diffused reflectance increases, indicating a better light scattering ability of nanoporous spheres due to the comparable size to the wavelength of visible light [27, 28].
Interestingly, full length AVEN was able to significantly increase sphere formation in the presence of miR30a overexpression to levels close to control empty-vector levels.
We show N1-ICD transactivates SOX2 to increase sphere formation, ALDH1+ and CD44+CD24low+cells.
