Summary:
In this work,ultrastructural study with electron microscope was carried out of
the tumor cell line Saos2, consisting of osteosarcoma cells with non-functional
p53 protein- after induction of p21CIP1/WAF1gene expression. The inducible cell
system Saos2-TetON p21 was used in four different p21CIP1/WAF1gene expression
time intervals, which, according to an earlier study by the Molecular
Carcinogenesis Group of the Histology and Embryology Lab., a gradual appearance
of senescence and eventually senescence escape of cell
subpopulationwasobserved. According to the previous study, in tumors with
mutated pRb/p53, a number of large cancer cells that surprisingly showed
colocalization of p21 and mitotic marker Ki67was observedimmunohistochemically.
This biological paradox was studied using the cellular system Saos2-TetON p21.
The gradual induction of p21 gene expression in Saos2-TetON p21 cells which
took place in this study, resulted in the induction of senescence in these
cells, which reached its peak on the 10th day. Further activation of p21
resulted in senescence escape (escaped cells) and survival of cell
subpopulation, whose ultrastructural study showed that have acquired
characteristics of aggressive tumor cells, such as multilobular
nuclei,micronuclei and mitochondria with defective morphology. In this work, we
used the experimental approaches of cell culturing and electron microscopy in
order to answer the above biological problem.
Keywords:
Senescence, Cancer, Genomic instability, Cell communication, Autophagy
