scholarly journals A Perspective of Epigenetic Regulation in Radiotherapy

2021 ◽  
Vol 9 ◽  
Author(s):  
Qin Peng ◽  
Kegui Weng ◽  
Shitian Li ◽  
Richard Xu ◽  
Yingxiao Wang ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Epigenetic Regulation ◽  
Hdac Inhibitors ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Cancer Therapeutics ◽  
The United States ◽  
Epigenetic Drugs ◽  
Epigenetic Remodeling ◽  
Dna Break

Radiation therapy (RT) has been employed as a tumoricidal modality for more than 100 years and on 470,000 patients each year in the United States. The ionizing radiation causes genetic changes and results in cell death. However, since the biological mechanism of radiation remains unclear, there is a pressing need to understand this mechanism to improve the killing effect on tumors and reduce the side effects on normal cells. DNA break and epigenetic remodeling can be induced by radiotherapy. Hence the modulation of histone modification enzymes may tune the radiosensitivity of cancer cells. For instance, histone deacetylase (HDAC) inhibitors sensitize irradiated cancer cells by amplifying the DNA damage signaling and inhibiting double-strand DNA break repair to influence the irradiated cells’ survival. However, the combination of epigenetic drugs and radiotherapy has only been evaluated in several ongoing clinical trials for limited cancer types, partly due to a lack of knowledge on the potential mechanisms on how radiation induces epigenetic regulation and chromatin remodeling. Here, we review recent advances of radiotherapy and radiotherapy-induced epigenetic remodeling and introduce related technologies for epigenetic monitoring. Particularly, we exploit the application of fluorescence resonance energy transfer (FRET) biosensors to visualize dynamic epigenetic regulations in single living cells and tissue upon radiotherapy and drug treatment. We aim to bridge FRET biosensor, epigenetics, and radiotherapy, providing a perspective of using FRET to assess epigenetics and provide guidance for radiotherapy to improve cancer treatment. In the end, we discuss the feasibility of a combination of epigenetic drugs and radiotherapy as new approaches for cancer therapeutics.

scholarly journals TR-FRET Cellular Assays for Interrogating Posttranslational Modifications of Histone H3

2011 ◽  
Vol 16 (10) ◽  
pp. 1236-1246 ◽  
Author(s):  
Thomas Machleidt ◽  
Matthew B. Robers ◽  
Spencer B. Hermanson ◽  
Jeanne M. Dudek ◽  
Kun Bi
Keyword(s):  
High Throughput ◽  
Posttranslational Modifications ◽  
Hdac Inhibitors ◽  
Histone H3 ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Green Fluorescence Protein ◽  
Time Resolved ◽  
Cellular Assays ◽  
Fluorescence Protein

Posttranslational modifications such as phosphorylation, acetylation, and methylation play important roles in regulating the structures and functions of histones, which in turn regulate gene expression and DNA repair and replication. Histone-modifying enzymes, such as deacetylases, methyltransferases and demethylases, have been pursued as therapeutic targets for various diseases. However, detection of the activities of these enzymes in high-throughput cell-based formats has remained challenging. The authors have developed high-throughput LanthaScreen cellular assays for Histone H3 site-specific modifications. These assays use cells expressing green fluorescence protein–tagged Histone H3 transiently delivered via BacMam and terbium-labeled anti–Histone H3 modification-specific antibodies. Robust time-resolved Förster resonance energy transfer signals were detected for H3 lysine-9 acetylation and dimethylation (H3K9me2), serine-10 phosphorylation, K4 di- and trimethylation, and K27 trimethylation. Consistent with previous reports, hypoxic stress increased K4 methylation levels, and methyltransferase G9a inhibitor UNC-0638 decreased K9me2 levels significantly, with little effects on other modifications. To demonstrate the utility of this assay platform in screening, the K9 acetylation assay was used to profile the Enzo Epigenetics Library. Twelve known HDAC inhibitors were identified as hits and followed up in a dose–response format. In conclusion, this assay platform enables high-throughput cell-based analysis of diverse types of posttranslational modifications of Histone H3.

scholarly journals Potential of phenothiazines to synergistically block calmodulin and reactivate PP2A in cancer cells

2021 ◽  
Author(s):  
Sunday Okutachi ◽  
Ganesh babu Manoharan ◽  
Daniel Abankwa
Keyword(s):  
Cancer Cells ◽  
Mapk Pathway ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Monoamine Neurotransmitter ◽  
Braf Mutations ◽  
Anti Cancer ◽  
Phosphatase 2A ◽  
Bret Assay

Phenothiazines (PTZ) are well known as inhibitors of monoamine neurotransmitter receptors, notably dopamine receptors. Because of this activity they are used for decades as antipsychotic drugs. In addition, significant anti-cancer properties have been ascribed to them. Several attempts for their repurposing were made, however, their incompletely understood polypharmacology is challenging. Here we examined the potential of PTZ to synergistically act on two cancer associated targets, calmodulin (CaM) and the tumor suppressor protein phosphatase 2A (PP2A). Both proteins are known to modulate the Ras-MAPK pathway activity. Consistently, combinations of a CaM inhibitor and a PP2A activator synergistically inhibited cancer cells with KRAS or BRAF mutations. We identified the covalently reactive PTZ derivative fluphenazine mustard as an inhibitor of Ras driven proliferation and Ras membrane organization. We confirmed its anti-CaM activity in vitro and through a cellular CaM target engagement bioluminescence resonance energy transfer (BRET) assay. Our results suggest that improved PTZ derivatives retaining their synergistic CaM inhibitory and PP2A activating properties, but without neurological side-effects, may be interesting to pursue further as anti-cancer agents.

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