scholarly journals Epigenetic Targeting of Autophagy via HDAC Inhibition in Tumor Cells: Role of p53

2018 ◽  
Vol 19 (12) ◽  
pp. 3952 ◽  
Author(s):  
Maria Mrakovcic ◽  
Lauren Bohner ◽  
Marcel Hanisch ◽  
Leopold F. Fröhlich

Tumor development and progression is the consequence of genetic as well as epigenetic alterations of the cell. As part of the epigenetic regulatory system, histone acetyltransferases (HATs) and deacetylases (HDACs) drive the modification of histone as well as non-histone proteins. Derailed acetylation-mediated gene expression in cancer due to a delicate imbalance in HDAC expression can be reversed by histone deacetylase inhibitors (HDACi). Histone deacetylase inhibitors have far-reaching anticancer activities that include the induction of cell cycle arrest, the inhibition of angiogenesis, immunomodulatory responses, the inhibition of stress responses, increased generation of oxidative stress, activation of apoptosis, autophagy eliciting cell death, and even the regulation of non-coding RNA expression in malignant tumor cells. However, it remains an ongoing issue how tumor cells determine to respond to HDACi treatment by preferentially undergoing apoptosis or autophagy. In this review, we summarize HDACi-mediated mechanisms of action, particularly with respect to the induction of cell death. There is a keen interest in assessing suitable molecular factors allowing a prognosis of HDACi-mediated treatment. Addressing the results of our recent study, we highlight the role of p53 as a molecular switch driving HDACi-mediated cellular responses towards one of both types of cell death. These findings underline the importance to determine the mutational status of p53 for an effective outcome in HDACi-mediated tumor therapy.

2020 ◽  
Vol 39 (2) ◽  
pp. 167-176 ◽  
Author(s):  
Bin Deng ◽  
Qing Luo ◽  
Alexander Halim ◽  
Qiuping Liu ◽  
Bingyu Zhang ◽  
...  

2000 ◽  
Vol 11 (6) ◽  
pp. 2069-2083 ◽  
Author(s):  
Ling Qiu ◽  
Andrew Burgess ◽  
David P. Fairlie ◽  
Helen Leonard ◽  
Peter G. Parsons ◽  
...  

Important aspects of cell cycle regulation are the checkpoints, which respond to a variety of cellular stresses to inhibit cell cycle progression and act as protective mechanisms to ensure genomic integrity. An increasing number of tumor suppressors are being demonstrated to have roles in checkpoint mechanisms, implying that checkpoint dysfunction is likely to be a common feature of cancers. Here we report that histone deacetylase inhibitors, in particular azelaic bishydroxamic acid, triggers a G2 phase cell cycle checkpoint response in normal human cells, and this checkpoint is defective in a range of tumor cell lines. Loss of this G2 checkpoint results in the tumor cells undergoing an aberrant mitosis resulting in fractured multinuclei and micronuclei and eventually cell death. This histone deacetylase inhibitor-sensitive checkpoint appears to be distinct from G2/M checkpoints activated by genotoxins and microtubule poisons and may be the human homologue of a yeast G2 checkpoint, which responds to aberrant histone acetylation states. Azelaic bishydroxamic acid may represent a new class of anticancer drugs with selective toxicity based on its ability to target a dysfunctional checkpoint mechanism in tumor cells.


2015 ◽  
Vol 35 (12) ◽  
pp. 1173-1188 ◽  
Author(s):  
Salma Afifi ◽  
Angela Michael ◽  
Mahshid Azimi ◽  
Mabel Rodriguez ◽  
Nikoletta Lendvai ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiao Meng ◽  
Glenn Young ◽  
Jingyu Chen

The bacterial cell envelope is a protective barrier at the frontline of bacterial interaction with the environment, and its integrity is regulated by various stress response systems. The Rcs (regulator of capsule synthesis) system, a non-orthodox two-component regulatory system (TCS) found in many members of the Enterobacteriaceae family, is one of the envelope stress response pathways. The Rcs system can sense envelope damage or defects and regulate the transcriptome to counteract stress, which is particularly important for the survival and virulence of pathogenic bacteria. In this review, we summarize the roles of the Rcs system in envelope stress responses (ESRs) and virulence regulation. We discuss the environmental and intrinsic sources of envelope stress that cause activation of the Rcs system with an emphasis on the role of RcsF in detection of envelope stress and signal transduction. Finally, the different regulation mechanisms governing the Rcs system’s control of virulence in several common pathogens are introduced. This review highlights the important role of the Rcs system in the environmental adaptation of bacteria and provides a theoretical basis for the development of new strategies for control, prevention, and treatment of bacterial infections.


2020 ◽  
Vol 21 (9) ◽  
pp. 3289 ◽  
Author(s):  
Hyeong Rok Yun ◽  
Yong Hwa Jo ◽  
Jieun Kim ◽  
Yoonhwa Shin ◽  
Sung Soo Kim ◽  
...  

Autophagy is a catabolic process for unnecessary or dysfunctional cytoplasmic contents by lysosomal degradation pathways. Autophagy is implicated in various biological processes such as programmed cell death, stress responses, elimination of damaged organelles and development. The role of autophagy as a crucial mediator has been clarified and expanded in the pathological response to redox signalling. Autophagy is a major sensor of the redox signalling. Reactive oxygen species (ROS) are highly reactive molecules that are generated as by-products of cellular metabolism, principally by mitochondria. Mitochondrial ROS (mROS) are beneficial or detrimental to cells depending on their concentration and location. mROS function as redox messengers in intracellular signalling at physiologically low level, whereas excessive production of mROS causes oxidative damage to cellular constituents and thus incurs cell death. Hence, the balance of autophagy-related stress adaptation and cell death is important to comprehend redox signalling-related pathogenesis. In this review, we attempt to provide an overview the basic mechanism and function of autophagy in the context of response to oxidative stress and redox signalling in pathology.


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