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Updated: May 8, 2026
Assays for Validating Histone Acetyltransferase Inhibitors
Published on: August 6, 2020
Selectively targeting prostate cancer with antiandrogen equipped histone deacetylase inhibitors
Berkley E Gryder1, Michelle J Akbashev, Michael K Rood
1Parker H. Petit Institute for Bioengineering & Biosciences, Department of Chemistry and Biochemistry, Georgia Institute of Technology , 315 Ferst Dr. NW, Atlanta, Georgia 30332-0230, United States.
Abstract:
Diverse cellular processes relevant to cancer progression are regulated by the acetylation status of proteins. Among such processes is chromatin remodeling via histone proteins, controlled by opposing histone deacetylase (HDAC) and histone acetyltransferase (HAT) enzymes. Histone deacetylase inhibitors (HDACi) show great promise in preclinical cancer models, but clinical trials treating solid tumors have failed to improve patient survival. This is due in part to an inability of HDACi to effectively accumulate in cancerous cells. To address this problem we designed HDACi with secondary pharmacophores to facilitate selective accumulation in malignant cells. We present the first example of HDACi compounds targeted to prostate tumors by equipping them with the additional ability to bind the androgen receptor (AR) with nonsteroidal antiandrogen moieties. Leads among these new dual-acting molecules bind to the AR and halt AR transcriptional activity at lower concentrations than clinical antiandrogens. They inhibit key isoforms of HDAC with low nanomolar potency. Fluorescent microscopy reveals varying degrees of AR nuclear localization in response to these compounds that correlates with their HDAC activity. These biological properties translate into potent anticancer activity against hormone-dependent (AR+) LNCaP and to a lesser extent against hormone-independent (AR-) DU145 prostate cancer, while having greatly reduced toxicity in noncancerous cells. This illustrates that engaging multiple biological targets with a single chemical probe can achieve both potent and cell-type-selective responses.
Insights
New dual-acting histone deacetylase inhibitors (HDACi) target prostate cancer by binding the androgen receptor (AR). These compounds show potent anticancer activity and reduced toxicity, offering a promising strategy for selective cancer therapy.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Protein acetylation regulates cancer progression, including chromatin remodeling by histone deacetylase (HDAC) and histone acetyltransferase (HAT) enzymes.
- Histone deacetylase inhibitors (HDACi) show preclinical promise but face challenges in clinical trials due to poor accumulation in cancer cells.
- Targeting cancer cells selectively is crucial for improving therapeutic efficacy and reducing side effects.
Purpose of the Study:
- To design novel HDAC inhibitors with enhanced selectivity for prostate cancer cells.
- To develop dual-acting compounds that inhibit HDAC activity and target the androgen receptor (AR).
- To evaluate the anticancer potential and toxicity profile of these novel dual-acting agents.
Main Methods:
- Synthesis of novel HDAC inhibitors incorporating nonsteroidal antiandrogen moieties for AR binding.
- Assessment of AR binding affinity and transcriptional activity inhibition.
- Evaluation of HDAC isoform inhibition potency (IC50 values).
- Fluorescent microscopy to observe AR nuclear localization in response to compounds.
- In vitro testing of anticancer activity against hormone-dependent (AR+) and hormone-independent (AR-) prostate cancer cell lines.
- Assessment of toxicity in noncancerous cells.
Main Results:
- Novel dual-acting compounds were synthesized, exhibiting potent binding to the AR and inhibiting its transcriptional activity at lower concentrations than clinical antiandrogens.
- These compounds effectively inhibit key HDAC isoforms with low nanomolar potency.
- Fluorescent microscopy demonstrated a correlation between AR nuclear localization and HDAC activity in response to the compounds.
- Significant anticancer activity was observed in AR+ LNCaP cells, with moderate activity in AR- DU145 cells.
- Reduced toxicity was noted in noncancerous cells compared to the anticancer effects.
Conclusions:
- Dual-acting chemical probes engaging both HDAC and AR targets can achieve potent and cell-type-selective anticancer responses.
- This strategy overcomes limitations of traditional HDACi by facilitating selective accumulation in malignant cells.
- The developed compounds represent a promising new class of therapeutics for prostate cancer treatment, particularly hormone-dependent types.
