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Updated: Jun 19, 2026
Assays for Validating Histone Acetyltransferase Inhibitors
Published on: August 6, 2020
[Effect of histone deacetylases inhibitor sodium butyrate (NaB) on transformants E1A + cHa-Ras expressing wild type
Abstract:
Induction of cellular senescence by various antitumour agents is a promising strategy of cancer treatment. We assessed the ability of sodium butyrate (NaB), a histone deacetylase inhibitor (HDACi), to reactivate the cellular senescence program in either E1A + cHa-Ras-transformed rat embryo fibroblasts with wild-type p53 (ERas(WT)) and in the isogenic cell line where p53 was inactivated due to expression of the potent genetic suppressor element GSE56 (ERas(GSE56)). NaB treatment increased p53 transcriptional activity and induced an irreversible G1/S cell cycle arrest in ERas(WT), but not in ERas(GSE56) cells. By the transient transfections method using reporter luciferase (p53-LUC) constructions, it was shown that p53-LUC activity as a marker of p53 transactivation function did not increase after X-rays exposure of transformants ERas(GSE56). p53 activity in transformants ERas(WT) increased both after irradiation or upon NaB treatment. Interestingly, the expression of senescence-associated beta-galactosidase (SA-beta-Gal), widely used as a marker of senescence, as well as loss of clonogenic ability, were observed in both cell lines following NaB treatment. Thus, our results suggest that induction of p53 transcription activity could be the key determinant of HDACi-induced cell cycle arrest and senescence in transformed cells and provide an additional evidence of SA-beta-Gal invalidity as a sufficient senescence marker.
Insights
Sodium butyrate (NaB), a histone deacetylase inhibitor, induces cell cycle arrest and senescence in cancer cells by increasing p53 activity. However, senescence-associated beta-galactosidase (SA-beta-Gal) is an unreliable marker for this process.
Area of Science:
- Oncology
- Cell Biology
- Molecular Biology
Background:
- Cellular senescence induction is a promising cancer treatment strategy.
- Histone deacetylase inhibitors (HDACi) like sodium butyrate (NaB) are explored for their anti-cancer effects.
- The role of p53 in HDACi-induced senescence requires further elucidation.
Purpose of the Study:
- To assess NaB's ability to induce cellular senescence in transformed rat embryo fibroblasts.
- To investigate the role of wild-type p53 (WT p53) versus inactivated p53 in NaB-mediated senescence.
- To evaluate the reliability of senescence-associated beta-galactosidase (SA-beta-Gal) as a senescence marker.
Main Methods:
- Utilized E1A + cHa-Ras-transformed rat embryo fibroblasts with wild-type p53 (ERas(WT)) and a p53-inactivated counterpart (ERas(GSE56)).
- Administered NaB and assessed p53 transcriptional activity, G1/S cell cycle arrest, and SA-beta-Gal expression.
- Employed transient transfections with p53-luciferase reporter constructs to measure p53 transactivation function after NaB treatment and X-ray exposure.
Main Results:
- NaB treatment increased p53 transcriptional activity and induced G1/S cell cycle arrest exclusively in ERas(WT) cells.
- p53-luciferase activity, a marker of p53 transactivation, did not increase in ERas(GSE56) cells upon X-ray exposure but did in ERas(WT) cells with NaB or irradiation.
- SA-beta-Gal expression and loss of clonogenic ability were observed in both cell lines after NaB treatment, irrespective of p53 status.
Conclusions:
- Induction of p53 transcriptional activity is a key determinant of HDACi-induced cell cycle arrest and senescence in transformed cells.
- SA-beta-Gal is not a sufficient marker for senescence, as it was induced by NaB even in the absence of functional p53.
- These findings highlight the critical role of p53 in mediating the anti-cancer effects of HDAC inhibitors.
