scholarly journals Polo-Like Kinase 1 Depletion Induces DNA Damage in Early S Prior to Caspase Activation

2009 ◽  
Vol 29 (10) ◽  
pp. 2609-2621 ◽  
Author(s):  
Hyungshin Yim ◽  
Raymond L. Erikson
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Dna Synthesis ◽  
Cancer Cells ◽  
S Phase ◽  
Mitotic Catastrophe ◽  
Serum Starvation ◽  
Dna Integrity ◽  
Normal Cells ◽  
Sequence Of Events

ABSTRACT Polo-like kinase 1 (Plk1) plays several roles in mitosis, and it has been suggested to have a role in tumorigenesis. We have previously reported that Plk1 depletion results in cell death in cancer cells, whereas normal cells survive similar depletion. However, Plk1 depletion together with p53 depletion induces cell death in normal cells as well. This communication presents evidence on the sequence of events that leads to cell death in cancer cells. DNA damage is detected at the first S phase following Plk1 depletion and is more severe in Plk1-depleted p53-null cancer cells. As a consequence of Plk1 depletion using lentivirus-based small interfering RNA techniques, prereplicative complex (pre-RC) formation is disrupted at the G1/S transition, and DNA synthesis is reduced during S phase of the first cycle after depletion. The levels of geminin, an inhibitor of DNA pre-RC, and Emi1, an inhibitor of anaphase-promoting complex/cyclosome, are elevated in Plk1-depleted cells. The rate of cell cycling is slower in Plk1-depleted cells than in control cells when synchronized by serum starvation. Plk1 depletion results in disrupted DNA pre-RC formation, reduced DNA synthesis, and DNA damage before cells display severe mitotic catastrophe or apoptosis. Our data suggest that Plk1 is required for cell cycle progression not only in mitosis but also for DNA synthesis, maintenance of DNA integrity, and prevention of cell death.

Recent Advances in Therapeutic Application of DNA Damage Response Inhibitors against Cancer

2021 ◽  
Vol 21 ◽  
Author(s):  
Stina George Fernandes ◽  
Prachi Shah ◽  
Ekta Khattar
Keyword(s):  
Dna Damage ◽  
Cancer Cells ◽  
Dna Damage Response ◽  
Dna Integrity ◽  
Normal Cells ◽  
Cellular Processes ◽  
Damage Response ◽  
Environmental Agents ◽  
Genomic Damage ◽  
Sensor Proteins

: DNA integrity is continuously challenged by intrinsic cellular processes and environmental agents. To overcome this genomic damage, cells have developed multiple signaling pathways collectively named as DNA damage response (DDR) and composed of three components: (i) sensor proteins, which detect DNA damage, (ii) mediators that relay the signal downstream and recruit the repair machinery, and (iii) the repair proteins, which restore the damaged DNA. A flawed DDR and failure to repair the damage lead to the accumulation of genetic lesions and increased genomic instability, which is recognized as a hallmark of cancer. Cancer cells tend to harbor increased mutations in DDR genes and often have fewer DDR pathways than normal cells. This makes cancer cells more dependent on particular DDR pathways and thus become more susceptible to compounds inhibiting those pathways compared to normal cells, which have all the DDR pathways intact. Understanding the roles of different DDR proteins in the DNA damage response and repair pathways and identification of their structures have paved the way for the development of their inhibitors as targeted cancer therapy. In this review, we describe the major participants of various DDR pathways, their significance in carcinogenesis, and focus on the inhibitors developed against several key DDR proteins.

scholarly journals Genome-wide screen of cell-cycle regulators in normal and tumor cells identifies a differential response to nucleosome depletion

2016 ◽  
Author(s):  
Maria Sokolova ◽  
Mikko Turunen ◽  
Oliver Mortusewicz ◽  
Teemu Kivioja ◽  
Patrick Herr ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cancer Cells ◽  
Tumor Cells ◽  
S Phase ◽  
Replication Forks ◽  
Cell Cycle Regulators ◽  
Normal Cells ◽  
Viable Cells ◽  
Genome Wide

AbstractTo identify cell cycle regulators that enable cancer cells to replicate DNA and divide in an unrestricted manner, we performed a parallel genome-wide RNAi screen in normal and cancer cell lines. In addition to many shared regulators, we found that tumor and normal cells are differentially sensitive to loss of the histone genes transcriptional regulator CASP8AP2. In cancer cells, loss of CASP8AP2 leads to a failure to synthesize sufficient amount of histones in the S-phase of the cell cycle, resulting in slowing of individual replication forks. Despite this, DNA replication fails to arrest, and tumor cells progress in an elongated S-phase that lasts several days, finally resulting in death of most of the affected cells. In contrast, depletion of CASP8AP2 in normal cells triggers a response that arrests viable cells in S-phase. The arrest is dependent on p53, and preceded by accumulation of markers of DNA damage, indicating that nucleosome depletion is sensed in normal cells via a DNA-damage-like response that is defective in tumor cells.

Anticancer Activity of Platinum (II) Complex with 2-Benzoylpyridine by Induction of DNA Damage, S-Phase Arrest, and Apoptosis

2020 ◽  
Vol 20 (4) ◽  
pp. 504-517
Author(s):  
Yu-Lan Li ◽  
Xin-Li Gan ◽  
Rong-Ping Zhu ◽  
Xuehong Wang ◽  
Duan-Fang Liao ◽  
...  
Keyword(s):  
Dna Damage ◽  
B Cell ◽  
Anticancer Activity ◽  
Cancer Cells ◽  
Hepg2 Cells ◽  
Caspase 3 ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
S Phase ◽  
Caspase 9

Objective: To overcome the disadvantages of cisplatin, numerous platinum (Pt) complexes have been prepared. However, the anticancer activity and mechanism of Pt(II) complexed with 2-benzoylpyridine [Pt(II)- Bpy]: [PtCl2(DMSO)L] (DMSO = dimethyl sulfoxide, L = 2-benzoylpyridine) in cancer cells remain unknown. Methods: Pt(II)-Bpy was synthesized and characterized by spectrum analysis. Its anticancer activity and underlying mechanisms were demonstrated at the cellular, molecular, and in vivo levels. Results: Pt(II)-Bpy inhibited tumor cell growth, especially HepG2 human liver cancer cells, with a halfmaximal inhibitory concentration of 9.8±0.5μM, but with low toxicity in HL-7702 normal liver cells. Pt(II)- Bpy induced DNA damage, which was demonstrated through a marked increase in the expression of cleavedpoly (ADP ribose) polymerase (PARP) and gamma-H2A histone family member X and a decrease in PARP expression. The interaction of Pt(II)-Bpy with DNA at the molecular level was most likely through an intercalation mechanism, which might be evidence of DNA damage. Pt(II)-Bpy initiated cell cycle arrest at the S phase in HepG2 cells. It also caused severe loss of the mitochondrial membrane potential; a decrease in the expression of caspase-9 and caspase-3; an increase in reactive oxygen species levels; the release of cytochrome c and apoptotic protease activation factor; and the activation of caspase-9 and caspase-3 in HepG2 cells, which in turn resulted in apoptosis. Meanwhile, changes in p53 and related proteins were observed including the upregulation of p53, the phosphorylation of p53, p21, B-cell lymphoma-2-associated X protein, and NOXA; and the downregulation of B-cell lymphoma 2. Moreover, Pt(II)-Bpy displayed marked inhibitory effects on tumor growth in the HepG2 nude mouse model. Conclusion: Pt(II)-Bpy is a potential candidate for cancer chemotherapy.

scholarly journals A radiosensitizer, gallotannin-rich extract from Bouea macrophylla seeds, inhibits radiation-induced epithelial-mesenchymal transition in breast cancer cells

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jiraporn Kantapan ◽  
Siwaphon Paksee ◽  
Aphidet Duangya ◽  
Padchanee Sangthong ◽  
Sittiruk Roytrakul ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Dna Damage ◽  
Cell Death ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Epithelial Mesenchymal Transition ◽  
Breast Cancer Cell Lines ◽  
Mesenchymal Transition ◽  
Mammosphere Formation ◽  
Radiation Induced

Abstract Background Radioresistance can pose a significant obstacle to the effective treatment of breast cancers. Epithelial–mesenchymal transition (EMT) is a critical step in the acquisition of stem cell traits and radioresistance. Here, we investigated whether Maprang seed extract (MPSE), a gallotannin-rich extract of seed from Bouea macrophylla Griffith, could inhibit the radiation-induced EMT process and enhance the radiosensitivity of breast cancer cells. Methods Breast cancer cells were pre-treated with MPSE before irradiation (IR), the radiosensitizing activity of MPSE was assessed using the colony formation assay. Radiation-induced EMT and stemness phenotype were identified using breast cancer stem cells (CSCs) marker (CD24−/low/CD44+) and mammosphere formation assay. Cell motility was determined via the wound healing assay and transwell migration. Radiation-induced cell death was assessed via the apoptosis assay and SA-β-galactosidase staining for cellular senescence. CSCs- and EMT-related genes were confirmed by real-time PCR (qPCR) and Western blotting. Results Pre-treated with MPSE before irradiation could reduce the clonogenic activity and enhance radiosensitivity of breast cancer cell lines with sensitization enhancement ratios (SERs) of 2.33 and 1.35 for MCF7 and MDA-MB231cells, respectively. Pretreatment of breast cancer cells followed by IR resulted in an increased level of DNA damage maker (γ-H2A histone family member) and enhanced radiation-induced cell death. Irradiation induced EMT process, which displayed a significant EMT phenotype with a down-regulated epithelial marker E-cadherin and up-regulated mesenchymal marker vimentin in comparison with untreated breast cancer cells. Notably, we observed that pretreatment with MPSE attenuated the radiation-induced EMT process and decrease some stemness-like properties characterized by mammosphere formation and the CSC marker. Furthermore, pretreatment with MPSE attenuated the radiation-induced activation of the pro-survival pathway by decrease the expression of phosphorylation of ERK and AKT and sensitized breast cancer cells to radiation. Conclusion MPSE enhanced the radiosensitivity of breast cancer cells by enhancing IR-induced DNA damage and cell death, and attenuating the IR-induced EMT process and stemness phenotype via targeting survival pathways PI3K/AKT and MAPK in irradiated breast cancer cells. Our findings describe a novel strategy for increasing the efficacy of radiotherapy for breast cancer patients using a safer and low-cost natural product, MPSE.

SPK1 is an essential S-phase-specific gene of Saccharomyces cerevisiae that encodes a nuclear serine/threonine/tyrosine kinase

1993 ◽  
Vol 13 (9) ◽  
pp. 5829-5842
Author(s):  
P Zheng ◽  
D S Fay ◽  
J Burton ◽  
H Xiao ◽  
J L Pinkham ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Damage ◽  
Dna Synthesis ◽  
Genomic Library ◽  
Excision Repair ◽  
Low Frequency ◽  
S Phase ◽  
Upstream Region ◽  
Specific Gene

SPK1 was originally discovered in an immunoscreen for tyrosine-protein kinases in Saccharomyces cerevisiae. We have used biochemical and genetic techniques to investigate the function of this gene and its encoded protein. Hybridization of an SPK1 probe to an ordered genomic library showed that SPK1 is adjacent to PEP4 (chromosome XVI L). Sporulation of spk1/+ heterozygotes gave rise to spk1 spores that grew into microcolonies but could not be further propagated. These colonies were greatly enriched for budded cells, especially those with large buds. Similarly, eviction of CEN plasmids bearing SPK1 from cells with a chromosomal SPK1 disruption yielded viable cells with only low frequency. Spk1 protein was identified by immunoprecipitation and immunoblotting. It was associated with protein-Ser, Thr, and Tyr kinase activity in immune complex kinase assays. Spk1 was localized to the nucleus by immunofluorescence. The nucleotide sequence of the SPK1 5' noncoding region revealed that SPK1 contains two MluI cell cycle box elements. These elements confer S-phase-specific transcription to many genes involved in DNA synthesis. Northern (RNA) blotting of synchronized cells verified that the SPK1 transcript is coregulated with other MluI box-regulated genes. The SPK1 upstream region also includes a domain highly homologous to sequences involved in induction of RAD2 and other excision repair genes by agents that induce DNA damage. spk1 strains were hypersensitive to UV irradiation. Taken together, these findings indicate that SPK1 is a dual-specificity (Ser/Thr and Tyr) protein kinase that is essential for viability. The cell cycle-dependent transcription, presence of DNA damage-related sequences, requirement for UV resistance, and nuclear localization of Spk1 all link this gene to a crucial S-phase-specific role, probably as a positive regulator of DNA synthesis.

scholarly journals Myrcene Exhibits Antitumor Activity Against Lung Cancer Cells by Inducing Oxidative Stress and Apoptosis Mechanisms

2020 ◽  
Vol 15 (9) ◽  
pp. 1934578X2096118
Author(s):  
Xudong Bai ◽  
Jin Tang
Keyword(s):  
Oxidative Stress ◽  
Lung Cancer ◽  
Dna Damage ◽  
Cell Death ◽  
Cancer Cells ◽  
Metabolic Activity ◽  
Lung Cancer Cells ◽  
Adenocarcinoma Cells ◽  
Lung Adenocarcinoma Cells ◽  
A549 Lung

Myrcene, a natural olefinic hydrocarbon, possesses anti-inflammatory, analgesic, antibiotic, and antimutagenic properties, but its anticancer effect has not yet been elucidated. Hence, the present study was framed to investigate the molecular mechanism by which myrcene mediates the anticancer activity of A549 lung adenocarcinoma cells. In vitro, A549 lung cancer cells were cultured either with or without myrcene, and the effects on cellular metabolic activity, levels of reactive oxygen species (ROS), mitochondrial integrity, deoxyribonucleic acid (DNA) damage, and activity of caspases were analyzed. The study demonstrated that compared with control cells, myrcene induces cell death in a dose-dependent manner while inducing ROS levels. Further experiments revealed that the metabolic activity of the A549 lung adenocarcinoma cells was diminished with increased DNA damage and altered cellular integrity. In addition, increased activity of caspase-3 was also evidenced with reduced mitochondrial membrane potential synthesis in the myrcene-treated cells, which demonstrate that lung cancer cells experience signs of toxicity during myrcene treatment through the activation of the apoptosis mechanism via mitochondria-mediated cell death signaling and induction of oxidative stress. The results provide the first report on the evidence of anticancer activity and the possibility of a new drug that could be used for the treatment of lung cancer.

scholarly journals Uniform Widespread Nuclear Phosphorylation of Histone H2AX Is an Indicator of Lethal DNA Replication Stress

Cancers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 355 ◽  
Author(s):  
Eric Moeglin ◽  
Dominique Desplancq ◽  
Sascha Conic ◽  
Mustapha Oulad-Abdelghani ◽  
Audrey Stoessel ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Cancer Cells ◽  
Drug Efficacy ◽  
Replication Stress ◽  
Strand Break ◽  
Histone H2ax ◽  
C Terminus ◽  
Dna Replication Stress ◽  
Stressed Cells

Phosphorylated histone H2AX (γ-H2AX), a central player in the DNA damage response (DDR), serves as a biomarker of DNA double-strand break repair. Although DNA damage is generally visualized by the formation of γ-H2AX foci in injured nuclei, it is unclear whether the widespread uniform nuclear γ-H2AX (called pan-nuclear) pattern occurring upon intense replication stress (RS) is linked to DDR. Using a novel monoclonal antibody that binds exclusively to the phosphorylated C-terminus of H2AX, we demonstrate that H2AX phosphorylation is systematically pan-nuclear in cancer cells stressed with RS-inducing drugs just before they die. The pan-nuclear γ-H2AX pattern is abolished by inhibition of the DNA-PK kinase. Cell death induction of cancer cells treated with increasing combinations of replication and kinase (ATR and Chk1) inhibitory drugs was proportional to the appearance of pan-nuclear γ-H2AX pattern. Delivery of labeled anti-γ-H2AX Fabs in stressed cells demonstrated at a single cell level that pan-nuclear γ-H2AX formation precedes irreversible cell death. Moreover, we show that H2AX is not required for RS-induced cell death in HeLa cells. Thus, the nuclear-wide formation of γ-H2AX is an incident of RS-induced cell death and, thus, the pan nuclear H2AX pattern should be regarded as an indicator of lethal RS-inducing drug efficacy.

Sign in / Sign up

Export Citation Format

Share Document