Combined inhibition of Rad51 and Wee1 enhances cell killing in HNSCC through induction of apoptosis associated with excessive DNA damage and replication stress

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer lacking targeted therapy. Here, we evaluated the anti-cancer activity of APR-246, a P53 activator, and CX-5461, a RNA polymerase I inhibitor, in the treatment of TNBC cells. We tested the efficacy of individual and combination therapy of CX-5461 and APR-246 in vitro, using a panel of breast cancer cell lines. Using publicly available breast cancer datasets, we found that components of RNA Pol I are predominately upregulated in basal-like breast cancer, compared to other subtypes, and this upregulation is associated with poor overall and relapse-free survival. Notably, we found that the treatment of breast cancer cells lines with CX-5461 significantly hampered cell proliferation and synergistically enhanced the efficacy of APR-246. The combination treatment significantly induced apoptosis that is associated with cleaved PARP and Caspase 3 along with Annexin V positivity. Likewise, we also found that combination treatment significantly induced DNA damage and replication stress in these cells. Our data provide a novel combination strategy by utilizing APR-246 in combination CX-5461 in killing TNBC cells that can be further developed into more effective therapy in TNBC therapeutic armamentarium.

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A Role for Histone H2B During Repair of UV-Induced DNA Damage in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/160.4.1375 ◽

2002 ◽

Vol 160 (4) ◽

pp. 1375-1387

Author(s):

Emmanuelle M D Martini ◽

Scott Keeney ◽

Mary Ann Osley

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Chromatin Structure ◽

Specific Effect ◽

Cell Killing ◽

Cyclobutane Pyrimidine Dimers ◽

Histone H2b ◽

Uv Sensitivity ◽

Pyrimidine Dimers

Abstract To investigate the role of the nucleosome during repair of DNA damage in yeast, we screened for histone H2B mutants that were sensitive to UV irradiation. We have isolated a new mutant, htb1-3, that shows preferential sensitivity to UV-C. There is no detectable difference in bulk chromatin structure or in the number of UV-induced cis-syn cyclobutane pyrimidine dimers (CPD) between HTB1 and htb1-3 strains. These results suggest a specific effect of this histone H2B mutation in UV-induced DNA repair processes rather than a global effect on chromatin structure. We analyzed the UV sensitivity of double mutants that contained the htb1-3 mutation and mutations in genes from each of the three epistasis groups of RAD genes. The htb1-3 mutation enhanced UV-induced cell killing in rad1Δ and rad52Δ mutants but not in rad6Δ or rad18Δ mutants, which are defective in postreplicational DNA repair (PRR). When combined with other mutations that affect PRR, the histone mutation increased the UV sensitivity of strains with defects in either the error-prone (rev1Δ) or error-free (rad30Δ) branches of PRR, but did not enhance the UV sensitivity of a strain with a rad5Δ mutation. When combined with a ubc13Δ mutation, which is also epistatic with rad5Δ, the htb1-3 mutation enhanced UV-induced cell killing. These results suggest that histone H2B acts in a novel RAD5-dependent branch of PRR.

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Targeting DNA Replication Stress and DNA Double-Strand Break Repair for Optimizing SCLC Treatment

Cancers ◽

10.3390/cancers11091289 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1289 ◽

Cited By ~ 4

Author(s):

Xing Bian ◽

Wenchu Lin

Keyword(s):

Lung Cancer ◽

Dna Damage ◽

Dna Replication ◽

Dna Damage Repair ◽

Predictive Biomarkers ◽

Replication Stress ◽

Genotoxic Stress ◽

Repair System ◽

Damage Repair ◽

Repair Pathways

Small cell lung cancer (SCLC), accounting for about 15% of all cases of lung cancer worldwide, is the most lethal form of lung cancer. Despite an initially high response rate of SCLC to standard treatment, almost all patients are invariably relapsed within one year. Effective therapeutic strategies are urgently needed to improve clinical outcomes. Replication stress is a hallmark of SCLC due to several intrinsic factors. As a consequence, constitutive activation of the replication stress response (RSR) pathway and DNA damage repair system is involved in counteracting this genotoxic stress. Therefore, therapeutic targeting of such RSR and DNA damage repair pathways will be likely to kill SCLC cells preferentially and may be exploited in improving chemotherapeutic efficiency through interfering with DNA replication to exert their functions. Here, we summarize potentially valuable targets involved in the RSR and DNA damage repair pathways, rationales for targeting them in SCLC treatment and ongoing clinical trials, as well as possible predictive biomarkers for patient selection in the management of SCLC.

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Replication stress-induced endogenous DNA damage drives cellular senescence induced by a sub-lethal oxidative stress

Nucleic Acids Research ◽

10.1093/nar/gkx684 ◽

2017 ◽

Vol 45 (18) ◽

pp. 10564-10582 ◽

Cited By ~ 25

Author(s):

Gireedhar Venkatachalam ◽

Uttam Surana ◽

Marie-Véronique Clément

Keyword(s):

Oxidative Stress ◽

Dna Damage ◽

Cellular Senescence ◽

Replication Stress

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Replication Stress and Telomere Dysfunction Are Present in Cultured Human Embryonic Stem Cells

Cytogenetic and Genome Research ◽

10.1159/000441245 ◽

2015 ◽

Vol 146 (4) ◽

pp. 251-260 ◽

Cited By ~ 3

Author(s):

Christine Janson ◽

Kristine Nyhan ◽

John P. Murnane

Keyword(s):

Stem Cells ◽

Dna Damage ◽

Embryonic Stem Cells ◽

Human Embryonic Stem Cells ◽

Chromosome Instability ◽

Embryonic Stem ◽

Replication Stress ◽

Activin A ◽

Fragile Sites ◽

Telomere Dysfunction

Replication stress causes DNA damage at fragile sites in the genome. DNA damage at telomeres can initiate breakage-fusion-bridge cycles and chromosome instability, which can result in replicative senescence or tumor formation. Little is known about the extent of replication stress or telomere dysfunction in human embryonic stem cells (hESCs). hESCs are grown in culture with the expectation of being used therapeutically in humans, making it important to minimize the levels of replication stress and telomere dysfunction. Here, the hESC line UCSF4 was cultured in a defined medium with growth factor Activin A, exogenous nucleosides, or DNA polymerase inhibitor aphidicolin. We used quantitative fluorescence in situ hybridization to analyze individual telomeres for dysfunction and observed that it can be increased by aphidicolin or Activin A. In contrast, adding exogenous nucleosides relieved dysfunction, suggesting that telomere dysfunction results from replication stress. Whether these findings can be applied to other hESC lines remains to be determined. However, because the loss of telomeres can lead to chromosome instability and cancer, we conclude that hESCs grown in culture for future therapeutic purposes should be routinely checked for replication stress and telomere dysfunction.

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Excess ribonucleotide reductase R2 subunits coordinate the S phase checkpoint to facilitate DNA damage repair and recovery from replication stress

Biochemical Pharmacology ◽

10.1016/j.bcp.2006.11.014 ◽

2007 ◽

Vol 73 (6) ◽

pp. 760-772 ◽

Cited By ~ 25

Author(s):

Z. Ping Lin ◽

Michael F. Belcourt ◽

Rocco Carbone ◽

Jana S. Eaton ◽

Philip G. Penketh ◽

...

Keyword(s):

Dna Damage ◽

Ribonucleotide Reductase ◽

Dna Damage Repair ◽

Replication Stress ◽

S Phase ◽

Damage Repair ◽

Ribonucleotide Reductase R2 ◽

S Phase Checkpoint

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DNA damage and repair in relation to cell killing in neocarzinostatin-treated HeLa cells

Biochimica et Biophysica Acta (BBA) - Nucleic Acids and Protein Synthesis ◽

10.1016/0005-2787(79)90007-8 ◽

1979 ◽

Vol 563 (1) ◽

pp. 59-71 ◽

Cited By ~ 31

Author(s):

Takumi Hatayama ◽

Irving H. Goldberg

Keyword(s):

Dna Damage ◽

Hela Cells ◽

Cell Killing ◽

Dna Damage And Repair

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Genomic and functional integrity of the hematopoietic system requires tolerance of oxidative DNA lesions

Blood ◽

10.1182/blood-2017-01-764274 ◽

2017 ◽

Vol 130 (13) ◽

pp. 1523-1534 ◽

Cited By ~ 14

Author(s):

Ana Martín-Pardillos ◽

Anastasia Tsaalbi-Shtylik ◽

Si Chen ◽

Seka Lazare ◽

Ronald P. van Os ◽

...

Keyword(s):

Dna Damage ◽

Mitochondrial Dysfunction ◽

Replication Stress ◽

Precursor Cells ◽

Dna Lesions ◽

Hematopoietic Stem ◽

Hematopoietic System ◽

Functional Integrity ◽

Key Points

Key Points Tolerance of oxidative DNA lesions ensures the genomic and functional integrity of hematopoietic stem and precursor cells. Endogenous DNA damage–induced replication stress is associated with mitochondrial dysfunction.

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