Abstract 125: Proteome Analysis of a Regulatory Pathway of Pathologic Vascular Injury as Mediated by KLF5 and its Transcriptional Complexes

Background: Transcription factor Krüppel-like factor 5 (KLF5) is a key element linking external stress and cardiovascular remodeling by up-regulating platelet derived growth factor (PDGF)-A chain gene activity. However, the underlying mechanisms remain to be elucidated. The unambiguous and comprehensive identification of interacting proteins is crucial for understanding these mechanisms. In the present study, we identified interacting factors of KLF5 by proteomic analysis and characterized their regulation in the vascular pathogenic response. Methods&Results: Double-stranded oligonucleotide containing the binding sequence for KLF5 in the PDGF-A promoter was synthesized and attached to metal beads, to which cell nuclear extract was applied. SDS-PAGE visualized specific bands to the sequence, which were subjected to in-gel digestion and peptide mass fingerprinting by MALDI-TOF/MS spectrometry. Factors that are known to be important in the DNA damage/repair pathway were successively identified. We therefore examined the involvement of the complex in vascular pathologies. Double-strand break as determined by immunohistochemistry using γ-H2AX antibody, a marker of activation of the double-stranded DNA damage/repair response, was observed in pathogenically stimulated vascular endothelial cells (HUVEC) and neointimal tissues in rat carotid artery balloon injury model. Further, KLF5 was shown to mediate the response on γ-H2AX as shown by co-immunoprecipitation and confocal microscopy. Discussion: We show a hitherto unknown regulatory mechanism by DNA double-strand break/repair system involving KLF5 in the vascular pathogenic response. Our findings might provide a clue to understanding the initiation of pathological cell proliferation observed in atherosclerosis or restenosis after coronary intervention. This new pathway might also be a tempting target for therapeutic intervention aimed at modulating the activity of KLF5 upon PDGF-A chain and its associated pathologies in the cardiovascular system.

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Recruitment of the Type B Histone Acetyltransferase Hat1p to Chromatin Is Linked to DNA Double-Strand Breaks

Molecular and Cellular Biology ◽

10.1128/mcb.26.9.3649-3658.2006 ◽

2006 ◽

Vol 26 (9) ◽

pp. 3649-3658 ◽

Cited By ~ 48

Author(s):

Song Qin ◽

Mark R. Parthun

Keyword(s):

Dna Damage ◽

Molecular Mechanisms ◽

Dna Damage Repair ◽

Strand Break ◽

Double Strand Break ◽

Similar Distribution ◽

Tail Domain ◽

Type B ◽

Direct Role ◽

Damage Repair

ABSTRACT Type B histone acetyltransferases are thought to catalyze the acetylation of the NH2-terminal tails of newly synthesized histones. Although Hat1p has been implicated in cellular processes, such as telomeric silencing and DNA damage repair, the underlying molecular mechanisms by which it functions remain elusive. In an effort to understand how Hat1p is involved in the process of DNA double-strand break (DSB) repair, we examined whether Hat1p is directly recruited to sites of DNA damage. Following induction of the endonuclease HO, which generates a single DNA DSB at the MAT locus, we found that Hat1p becomes associated with chromatin near the site of DNA damage. The nuclear Hat1p-associated histone chaperone Hif1p is also recruited to an HO-induced DSB with a similar distribution. In addition, while the acetylation of all four histone H4 NH2-terminal tail domain lysine residues is increased following DSB formation, only the acetylation of H4 lysine 12, the primary target of Hat1p activity, is dependent on the presence of Hat1p. Kinetic analysis of Hat1p localization indicates that it is recruited after the phosphorylation of histone H2A S129 and concomitant with the recombinational-repair factor Rad52p. Surprisingly, Hat1p is still recruited to chromatin in strains that cannot repair an HO-induced double-strand break. These results indicate that Hat1p plays a direct role in DNA damage repair and is responsible for specific changes in histone modification that occur during the course of recombinational DNA repair.

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DNA Damage Repair and DNA Methylation in the Kidney

American Journal of Nephrology ◽

10.1159/000501356 ◽

2019 ◽

Vol 50 (2) ◽

pp. 81-91 ◽

Cited By ~ 4

Author(s):

Kaori Hayashi ◽

Akihito Hishikawa ◽

Hiroshi Itoh

Keyword(s):

Dna Methylation ◽

Dna Damage ◽

Dna Repair ◽

Methylation Status ◽

Dna Damage Repair ◽

Strand Break ◽

Repair System ◽

Damage Repair ◽

Dna Double Strand Break ◽

Cell Type Specific

The DNA repair system is essential for the maintenance of genome integrity and is mainly investigated in the areas of aging and cancer. The DNA repair system is strikingly cell-type specific, depending on the expression of DNA repair factors; therefore, different DNA repair systems may exist in each type of kidney cell. Importance of DNA repair in the kidney is suggested by renal phenotypes caused by both genetic mutations in the DNA repair pathway and increased stimuli of DNA damage. Recently, we reported the importance of DNA double-strand break repair in glomerular podocytes and its involvement in the alteration of DNA methylation status, which regulates podocyte phenotypes. In this review, we summarize the roles of the DNA repair system in the kidneys and possible associations with altered kidney DNA methylation, which have been infrequently reported together. Investigations of DNA damage repair and epigenetic changes in the kidneys may achieve a profound understanding of kidney aging and diseases.

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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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MAP4K1 functions as a tumor promotor and drug mediator for AML via modulation of DNA damage/repair system and MAPK pathway

EBioMedicine ◽

10.1016/j.ebiom.2021.103441 ◽

2021 ◽

Vol 69 ◽

pp. 103441

Author(s):

Qing Ling ◽

Fenglin Li ◽

Xiang Zhang ◽

Shihui Mao ◽

Xiangjie Lin ◽

...

Keyword(s):

Dna Damage ◽

Mapk Pathway ◽

Dna Damage Repair ◽

Repair System ◽

Damage Repair ◽

Tumor Promotor

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Deeper Insight in Metastatic Cancer progression;Epithelial-to-Mesenchymal Transition and Genomic Instability: implications on treatment resistance

Current Molecular Medicine ◽

10.2174/1566524021666210202114844 ◽

2021 ◽

Vol 21 ◽

Author(s):

Kenneth Omabe ◽

Sandra Uduituma ◽

David Igwe ◽

Maxwell Omabe

Keyword(s):

Dna Damage ◽

Cancer Treatment ◽

Epithelial To Mesenchymal Transition ◽

Dna Damage Repair ◽

Treatment Resistance ◽

Therapy Resistance ◽

Cellular Reprogramming ◽

Repair System ◽

Mesenchymal Transition ◽

Damage Repair

: Therapy resistance remains the major obstacle to successful cancer treatment. Epithelial-to- mesenchymal transition [EMT], a cellular reprogramming process involved in embryogenesis and organ development and regulated by a number of transcriptional factors [EMT-TFs] such as ZEB1/2, is recognized for its role in tumor progression and metastasis. Recently, a growing body of evidence has implicated EMT in cancer therapy resistance but the actual mechanism that underlie this finding has remained elusive. For example, whether it is, the EMT states in itself or the EMT-TFs that modulates chemo or radio-resistance in cancer is still contentious. Here, we summarise the molecular mechanisms of EMT program and chemotherapeutic resistance in cancer with specific reference to DNA damage response [DDR]. We provide an insight into the molecular interplay that exist between EMT program and DNA repair machinery in cancer and how this interaction influences therapeutic response. We review conflicting studies linking EMT and drug resistance via the DNA damage repair axis. We draw scientific evidence demonstrating how several molecular signalling, including EMT-TFs work in operational harmony to induce EMT and confer stemness properties on the EMT-susceptible cells. We highlight the role of enhanced DNA damage repair system associated with EMT-derived stem cell-like states in promoting therapy resistance and suggest a multi-targeting modality in combating cancer treatment resistance.

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Effect of enzalutamide on sensitivity in prostate cancer cells to radiation by inhibition of DNA double strand break repair.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.6_suppl.208 ◽

2017 ◽

Vol 35 (6_suppl) ◽

pp. 208-208 ◽

Cited By ~ 2

Author(s):

Maryam Ghashghaei ◽

Thierry Muanza ◽

Miltiadis Paliouras ◽

Tamim Niazi

Keyword(s):

Prostate Cancer ◽

Dna Damage ◽

Dna Damage Repair ◽

Strand Break ◽

Dependent Manner ◽

Castration Resistance ◽

Concurrent Administration ◽

Damage Repair ◽

Pathway Inhibition ◽

Approved Drugs

208 Background: Prostate cancer is the second leading cause of cancer-related deaths amongst men in North America. Data suggests that, following radiation therapy (XRT), androgen receptor (AR) enhances DNA damage repair and contributes to resistance of prostate cancer (PCa) cells to XRT. At present AR-pathway inhibition is the mainstay treatment of metastatic castration resistance prostate cancer (mCRPC). Enzalutamide (ENZA), a potent AR inhibitor is one of the approved drugs in this setting. The purpose of this study was to assess the potential radiosensitization of ENZA and its mechanism of action in hormone resistant PCa cells. Methods: The effect of ENZA alone or in combination with XRT was assessed on hormone-sensitive, (HS: LNCaP, PC3-T877A) and insensitive PCa cells (HI: PC3, PC3-AR V7, C4-2) using viability and clonogenic assays, cell cycle arrest and DNA damage analysis. Results: MTT assay demonstrates that ENZA significantly inhibits the proliferation of HS PCa cells in a dose dependent manner whereas CRPC required ENZA in combination with ADT (androgen deprivation therapy). Additionally, clonogenic assay proves that concurrent administration of ENZA or ADT+ENZA and XRT led to a supra-additive antitumor effect with the dose enhancement factor of 1.76±0.008 in LNCaP, 1.65±0.01 in PC3-T877A and 1.35±0.003 in C4-2 respectively at surviving fraction of 0.1. This effect was not observed in PC3 and PC3-AR V7 cells pre-treated with ENZA (in all cases DEF = 1 at SF = 0.1). Additionally, the level of γH2AX increased in HS cells and CRPC cells treated with ENZA/ADT+ENZA and XRT when compared to XRT alone. The enhanced H2AX activity remained unchanged up to 24 hours after combination treatment. Furthermore, there is an initial inhibition of DNA-PKcs in HS and CRPC cells treated with ENZA/ADT+ENZA administered before XRT. Conclusions: Our data suggest that the higher efficacy of ENZA/ENZA+ADT and XRT could be partially due to inhibition of DNA damage repair. Our results demonstrated a significant enhancement of XRT efficacy and confirms the rational for the ongoing combination clinical trials with XRT.

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DUSP1 enhances the chemoresistance of gallbladder cancer via the modulation of the p38 pathway and DNA damage/repair system

Oncology Letters ◽

10.3892/ol.2018.8822 ◽

2018 ◽

Author(s):

Jun Fang ◽

Zhimin Ye ◽

Feiying Gu ◽

Maohui Yan ◽

Qingren Lin ◽

...

Keyword(s):

Dna Damage ◽

Gallbladder Cancer ◽

Dna Damage Repair ◽

Repair System ◽

Damage Repair ◽

P38 Pathway

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Persistent DNA Double-Strand Breaks After Repeated Diagnostic CT Scans in Breast Epithelial Cells and Lymphocytes

Frontiers in Oncology ◽

10.3389/fonc.2021.634389 ◽

2021 ◽

Vol 11 ◽

Author(s):

Natalia V. Bogdanova ◽

Nina Jguburia ◽

Dhanya Ramachandran ◽

Nora Nischik ◽

Katharina Stemwedel ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Repair ◽

Cell Types ◽

Strand Break ◽

Ct Scans ◽

Breast Epithelial Cell ◽

Damage Repair ◽

Breast Epithelial ◽

The Impact ◽

Diagnostic Ct

DNA double-strand break (DSB) induction and repair have been widely studied in radiation therapy (RT); however little is known about the impact of very low exposures from repeated computed tomography (CT) scans for the efficiency of repair. In our current study, DSB repair and kinetics were investigated in side-by-side comparison of RT treatment (2 Gy) with repeated diagnostic CT scans (≤20 mGy) in human breast epithelial cell lines and lymphoblastoid cells harboring different mutations in known DNA damage repair proteins. Immunocytochemical analysis of well known DSB markers γH2AX and 53BP1, within 48 h after each treatment, revealed highly correlated numbers of foci and similar appearance/disappearance profiles. The levels of γH2AX and 53BP1 foci after CT scans were up to 30% of those occurring 0.5 h after 2 Gy irradiation. The DNA damage repair after diagnostic CT scans was monitored and quantitatively assessed by both γH2AX and 53BP1 foci in different cell types. Subsequent diagnostic CT scans in 6 and/or 12 weeks intervals resulted in elevated background levels of repair foci, more pronounced in cells that were prone to genomic instability due to mutations in known regulators of DNA damage response (DDR). The levels of persistent foci remained enhanced for up to 6 months. This “memory effect” may reflect a radiation-induced long-term response of cells after low-dose x-ray exposure.

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Novel Insights into the Molecular Regulation of Ribonucleotide Reductase in Adrenocortical Carcinoma Treatment

Cancers ◽

10.3390/cancers13164200 ◽

2021 ◽

Vol 13 (16) ◽

pp. 4200

Author(s):

Christina Bothou ◽

Ashish Sharma ◽

Adrian Oo ◽

Baek Kim ◽

Pal Perge ◽

...

Keyword(s):

Dna Damage ◽

Ribonucleotide Reductase ◽

Ataxia Telangiectasia ◽

Therapeutic Option ◽

Treatment Options ◽

Dna Damage Repair ◽

Repair System ◽

Clinical Patient ◽

Damage Repair ◽

Adrenocortical Carcinomas

Current systemic treatment options for patients with adrenocortical carcinomas (ACCs) are far from being satisfactory. DNA damage/repair mechanisms, which involve, e.g., ataxia-telangiectasia-mutated (ATM) and ataxia-telangiectasia/Rad3-related (ATR) protein signaling or ribonucleotide reductase subunits M1/M2 (RRM1/RRM2)-encoded ribonucleotide reductase (RNR) activation, commonly contribute to drug resistance. Moreover, the regulation of RRM2b, the p53-induced alternative to RRM2, is of unclear importance for ACC. Upon extensive drug screening, including a large panel of chemotherapies and molecular targeted inhibitors, we provide strong evidence for the anti-tumoral efficacy of combined gemcitabine (G) and cisplatin (C) treatment against the adrenocortical cell lines NCI-H295R and MUC-1. However, accompanying induction of RRM1, RRM2, and RRM2b expression also indicated developing G resistance, a frequent side effect in clinical patient care. Interestingly, this effect was partially reversed upon addition of C. We confirmed our findings for RRM2 protein, RNR-dependent dATP levels, and modulations of related ATM/ATR signaling. Finally, we screened for complementing inhibitors of the DNA damage/repair system targeting RNR, Wee1, CHK1/2, ATR, and ATM. Notably, the combination of G, C, and the dual RRM1/RRM2 inhibitor COH29 resulted in previously unreached total cell killing. In summary, we provide evidence that RNR-modulating therapies might represent a new therapeutic option for ACC.

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