| External factors: | Valproic acid |
| Aging type: | Accelerate |
| Aging characteristic: |
| Category: | Chemical compounds |
| Phenotype: | Medulloblastoma |
| Experiment: | SA-β-gal activity assay//Flow cytometry//Cell morphological analysis |
| Description: | We confirmed that cellular senescence was indeed induced in those flattened D283-MED and DAOY cells by valproic acid (0.6 and 1 mmol/L) in a time- and dose-dependent manner. More interestingly, in D283-MED cells treated with valproic acid (0.6 mmol/L), we observed blue staining in the gradually dissociating cell spheroids as well. The induced senescence started from day 3 and peaked on day 7 when the whole spheroids were densely stained. A higher valproic acid concentration (1 mmol/L) led to more dramatic increase of cellular senescence as evidenced by further depletion of spheroids and increased β-galactosidase staining of attached D283-MED cells. In D283-MED and DAOY cells, shift of cell population to G1-G0 phases started after 3 days of valproic acid (1 or 2.7 mmol/L) treatment. More significant cell cycle arrest, however, was detected on day 7, when cells in G1-G0 phases increased and cells in G2-M phases decreased concurrently. |
| Target gene: | CDK4 |
| R-EF-Target gene: | Downregulation |
| Official symbol(s): | CDK4 |
| Target gene experiment: | Western blot//qPCR |
| Target gene description: | The expression of CDK4, however, was significantly altered by valproic acid. Suppression of CDK4 mRNA expression was most prominent in D283-MED cells, and a corresponding decline in protein levels, although less dramatic, was also observed. In DAOY cells, although the inhibition of mRNA transcript levels was not major, a dramatic depletion of CDK4 protein was observed. |
| Regulatory pathway: | -- |
| R-EF-Pathway: | -- |
| Pathway experiment: | -- |
| Pathway description: | -- |
Annotation: