scholarly journals Metabolic perturbation of epigenome by inhibiting S-adenosylhomocysteine hydrolase elicits senescence through DNA damage response in hepatoma cells

Tumor Biology ◽  
2017 ◽  
Vol 39 (5) ◽  
pp. 101042831769911 ◽  
Author(s):  
Guozhen Wu ◽  
Ning Wang ◽  
Ying Luo ◽  
Yanyan Zhang ◽  
Peng Wang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cancer Cells ◽  
Dna Damage Response ◽  
Cellular Senescence ◽  
Genotoxic Stress ◽  
Hepatoma Cells ◽  
Adenosylhomocysteine Hydrolase ◽  
Dna Damaging Agents ◽  
Metabolic Perturbation ◽  
Damage Response

Cellular senescence is a key physiological barrier against tumor and represents an option for therapeutic intervention. One pivotal intracellular stimulus causing senescence is DNA damage response, while the senescence-associated heterochromatin in cancer limits the strength of the DNA damage response to endogenous genotoxic stress or DNA-damaging agents. Therefore, targeting the maintenance of compacted chromatin in cancer cells represents an optional intervention to improve the therapeutic efficacy in cancer treatment. Given a crosstalk between methionine cycle and histone methylation, we hypothesize that pharmacologically disrupting methylation potential, defined as the ratio of cellular S-adenosylmethionine to S-adenosylhomocysteine, could affect the chromatin structures in cancer cells and thus enhance their sensitivity to DNA damage response signaling. Our results showed that 3-deazaneplanocin A, a chemical inhibitor of S-adenosylhomocysteine hydrolase, elicited a typical cellular senescence in hepatoma cells. Therapy-induced senescence by 3-deazaneplanocin A was mediated through p53–p21 pathway and triggered by enhanced ataxia-telangiectasia mutated activation related to chromatin changes. In conclusion, our study demonstrated that metabolic perturbation of chromatin status in oncogene-activated cancers could be an optional intervention to sensitize DNA damage response signaling.

scholarly journals Scorpins in the DNA Damage Response

2018 ◽  
Author(s):  
Dario Palmieri ◽  
Anna Tessari ◽  
Vincenzo Coppola
Keyword(s):  
Dna Damage ◽  
Cancer Cells ◽  
Dna Damage Response ◽  
Cell Cycle Progression ◽  
Genotoxic Stress ◽  
Published Evidence ◽  
Damage Response ◽  
Increased Sensitivity ◽  
Activate Complex ◽  
And Migration

The DNA Damage Response (DDR) is a complex signaling network that comes into play when cells experience genotoxic stress. Upon DNA damage, cellular signaling pathways are rewired to slow down cell cycle progression and allow recovery. However, when the damage is beyond repair, cells activate complex and still not fully understood mechanisms, leading to a complete proliferative arrest or cell death. A number of conventional and novel anti-neoplastic treatments rely on causing DNA damage or on the inhibition of the DDR in cancer cells. However, the identification of molecular determinants directing cancer cells toward recovery or death upon DNA damage is still far from complete, and it is object of intense investigation. SPRY-COntaining RAN binding Proteins (Scorpins) RANBP9 and RANBP10 are evolutionarily conserved and ubiquitously expressed proteins whose biological functions are still debated. RANBP9 has been previously implicated in cell proliferation, survival, apoptosis and migration. Recent studies also showed that RANBP9 is involved in the Ataxia Telangiectasia Mutated (ATM) signaling upon DNA damage. Accordingly, cells lacking RANBP9 show increased sensitivity to genotoxic treatment. Although there is no published evidence, extensive protein similarities suggest that RANBP10 might have partially overlapping functions with RANBP9. Like RANBP9, RANBP10 bears sites putative target of PIK-kinases and high throughput studies found RANBP10 to be phosphorylated following genotoxic stress. Therefore, this second Scorpin might be another overlooked player of the DDR alone or in combination with RANBP9. This review focuses on the relatively unknown role played by RANBP9 and RANBP10 in responding to genotoxic stress.

The JNK Pathway Is a Significant Determinant of Sensitivity to DNA Damaging Agents in Pre-B ALL.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3786-3786
Author(s):  
Philip O. Saunders ◽  
Kenneth F Bradstock ◽  
Linda J. Bendall
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Death ◽  
Dna Damage Response ◽  
Genotoxic Stress ◽  
Jnk Pathway ◽  
Dna Damaging Agents ◽  
Pathway Activation ◽  
Damage Response ◽  
Jnk Activation

Abstract Abstract 3786 Poster Board III-722 The JNK pathway is reported to facilitate AP1 binding and promote apoptosis depending on cell type and environmental conditions. We have previously reported RAD001 (16μM) induces JNK pathway activation in pre-B ALL cells. We sought to evaluate the impact of changes in JNK pathway activation on pre-B ALL viability in vitro. Using JNK inhibitor SP600125 titrated to inhibit c-Jun activation, we determined that cell death in pre-B ALL cells treated with RAD001 (16μM) alone was not JNK dependent. In contrast, combining RAD001 (16μM) with DNA damaging agents significantly enhanced JNK dependent death. This difference indicates that additional factors, including genotoxic stress, are required for JNK activation to induce pre-B ALL cell death. The JNK pathway is reported to suppress transcriptional activation of key mediators of the DNA damage response. We observed that JNK activation in cells treated with RAD001 (16μM) and DNA damaging agents was associated with suppression of p53 and p21 relative to DNA damage alone. This result was supported by the observation of enhanced p53 and p21 expression in pre-B ALL cells treated with DNA damaging agents in the presence of the JNK inhibitor SP600125. Analysis of DNA content and proliferation antigen expression in pre-B ALL cells treated with RAD001 (16μM) and DNA damaging agents revealed JNK activation was associated with a significant increase in the proportion of cells in S phase, relative to DNA damage alone, which caused a G1 and G2 cell cycle arrest. Further evidence that the JNK pathway impacts on the DNA damage response was provided by the observation that pre-B ALL cells treated with DNA damaging agents and JNK inhibitor SP600125 demonstrated reduced PCNA expression at G1 and G2 and reduced expression of mitotic antigen phospho-Histone–H3. This is consistent with enhanced regulation at G1-S and G2-M checkpoints. The results indicate changes in JNK pathway activation impact on the cell cycle response to DNA damage. In conclusion we have identified that the JNK pathway has a significant impact on the sensitivity of pre-B ALL cells to DNA damaging agents. JNK activation in the presence of genotoxic stress significantly enhanced pre-B ALL cell death, associated with suppression of key mediators of the DNA damage response, p53 and p21. We found that changes in JNK activation altered the cell cycle response to DNA damage. Further study is required to determine if changes in cell cycle regulation in the presence of DNA damage is causal to JNK dependent cell death. Additional studies to identify intracellular signal pathways which facilitate JNK dependent cell death are warranted. Our observations suggest combining agents which induce JNK activation with conventional chemotherapy or selected novel agents has the potential to enhance clinical responses in pre-B ALL. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Rb Regulates DNA Damage Response and Cellular Senescence through E2F-Dependent Suppression of N-Ras Isoprenylation

Cancer Cell ◽  
2009 ◽  
Vol 15 (4) ◽  
pp. 255-269 ◽  
Author(s):  
Awad Shamma ◽  
Yujiro Takegami ◽  
Takao Miki ◽  
Shunsuke Kitajima ◽  
Makoto Noda ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Cellular Senescence ◽  
Damage Response

scholarly journals APE2 Is a General Regulator of the ATR-Chk1 DNA Damage Response Pathway to Maintain Genome Integrity in Pancreatic Cancer Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Md Akram Hossain ◽  
Yunfeng Lin ◽  
Garrett Driscoll ◽  
Jia Li ◽  
Anne McMahon ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pancreatic Cancer ◽  
Dna Damage ◽  
Cancer Cells ◽  
Dna Damage Response ◽  
Human Pancreatic Cancer ◽  
Genome Integrity ◽  
Pancreatic Cancer Cells ◽  
Damage Response ◽  
Egg Extracts

The maintenance of genome integrity and fidelity is vital for the proper function and survival of all organisms. Recent studies have revealed that APE2 is required to activate an ATR-Chk1 DNA damage response (DDR) pathway in response to oxidative stress and a defined DNA single-strand break (SSB) in Xenopus laevis egg extracts. However, it remains unclear whether APE2 is a general regulator of the DDR pathway in mammalian cells. Here, we provide evidence using human pancreatic cancer cells that APE2 is essential for ATR DDR pathway activation in response to different stressful conditions including oxidative stress, DNA replication stress, and DNA double-strand breaks. Fluorescence microscopy analysis shows that APE2-knockdown (KD) leads to enhanced γH2AX foci and increased micronuclei formation. In addition, we identified a small molecule compound Celastrol as an APE2 inhibitor that specifically compromises the binding of APE2 but not RPA to ssDNA and 3′-5′ exonuclease activity of APE2 but not APE1. The impairment of ATR-Chk1 DDR pathway by Celastrol in Xenopus egg extracts and human pancreatic cancer cells highlights the physiological significance of Celastrol in the regulation of APE2 functionalities in genome integrity. Notably, cell viability assays demonstrate that APE2-KD or Celastrol sensitizes pancreatic cancer cells to chemotherapy drugs. Overall, we propose APE2 as a general regulator for the DDR pathway in genome integrity maintenance.

scholarly journals Role of the circadian clock "Death-Loop" in the DNA damage response underpinning cancer treatment resistance

2022 ◽  
Author(s):  
Ninel Miriam Vainshelbaum ◽  
Kristine Salmina ◽  
Bogdan I Gerashchenko ◽  
Marija Lazovska ◽  
Pawel Zayakin ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Circadian Clock ◽  
Cancer Cells ◽  
Dna Damage Response ◽  
Embryonic Stem ◽  
Early Embryo ◽  
Mitotic Slippage ◽  
Damage Response ◽  
Telomere Regulation

The Circadian Clock (CC) drives the normal cell cycle and reciprocally regulates telomere elongation. However, it can be deregulated in cancer, embryonic stem cells (ESC) and the early embryo. Here, its role in the resistance of cancer cells to genotoxic treatments was assessed in relation to whole-genome duplication (WGD) and telomere regulation. We first evaluated the DNA damage response of polyploid cancer cells and observed a similar impact on the cell cycle to that seen in ESC - overcoming G1/S, adapting DNA damage checkpoints, tolerating DNA damage, and coupling telomere erosion to accelerated cell senescence, favouring transition by mitotic slippage into the ploidy cycle (reversible polyploidy). Next, we revealed a positive correlation between cancer WGD and deregulation of CC assessed by bioinformatics on 11 primary cancer datasets (rho=0.83; p<0.01). As previously shown, the cancer cells undergoing mitotic slippage cast off telomere fragments with TERT, restore the telomeres by recombination and return their depolyploidised mitotic offspring to TERT-dependent telomere regulation. Through depolyploidisation and the CC "death loop", the telomeres and Hayflick limit count are thus again renewed. This mechanism along with similar inactivity of the CC in early embryos supports a life-cycle (embryonic) concept of cancer.

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