scholarly journals LINC-PINT impedes DNA repair and enhances radiotherapeutic response by targeting DNA-PKcs in nasopharyngeal cancer

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
You-hong Wang ◽  
Zhen Guo ◽  
Liang An ◽  
Yong Zhou ◽  
Heng Xu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Nasopharyngeal Cancer ◽  
Noncoding Rnas ◽  
Dependent Protein Kinase ◽  
Damage Repair ◽  
Dependent Protein ◽  
Cancer Tissues

AbstractRadioresistance continues to be the leading cause of recurrence and metastasis in nasopharyngeal cancer. Long noncoding RNAs are emerging as regulators of DNA damage and radioresistance. LINC-PINT was originally identified as a tumor suppressor in various cancers. In this study, LINC-PINT was significantly downregulated in nasopharyngeal cancer tissues than in rhinitis tissues, and low LINC-PINT expressions showed poorer prognosis in patients who received radiotherapy. We further identified a functional role of LINC-PINT in inhibiting the malignant phenotypes and sensitizing cancer cells to irradiation in vitro and in vivo. Mechanistically, LINC-PINT was responsive to DNA damage, inhibiting DNA damage repair through ATM/ATR-Chk1/Chk2 signaling pathways. Moreover, LINC-PINT increased radiosensitivity by interacting with DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and negatively regulated the expression and recruitment of DNA-PKcs. Therefore, these findings collectively support the possibility that LINC-PINT serves as an attractive target to overcome radioresistance in NPC.

scholarly journals SIRT7-mediated ATM deacetylation is essential for its deactivation and DNA damage repair

2019 ◽  
Vol 5 (3) ◽  
pp. eaav1118 ◽  
Author(s):  
Ming Tang ◽  
Zhiming Li ◽  
Chaohua Zhang ◽  
Xiaopeng Lu ◽  
Bo Tu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Repair ◽  
Class Iii ◽  
Ataxia Telangiectasia Mutated ◽  
Damage Repair ◽  
Damage Response ◽  
Late Stages

The activation of ataxia-telangiectasia mutated (ATM) upon DNA damage involves a cascade of reactions, including acetylation by TIP60 and autophosphorylation. However, how ATM is progressively deactivated after completing DNA damage repair remains obscure. Here, we report that sirtuin 7 (SIRT7)–mediated deacetylation is essential for dephosphorylation and deactivation of ATM. We show that SIRT7, a class III histone deacetylase, interacts with and deacetylates ATM in vitro and in vivo. In response to DNA damage, SIRT7 is mobilized onto chromatin and deacetylates ATM during the late stages of DNA damage response, when ATM is being gradually deactivated. Deacetylation of ATM by SIRT7 is prerequisite for its dephosphorylation by its phosphatase WIP1. Consequently, depletion of SIRT7 or acetylation-mimic mutation of ATM induces persistent ATM phosphorylation and activation, thus leading to impaired DNA damage repair. Together, our findings reveal a previously unidentified role of SIRT7 in regulating ATM activity and DNA damage repair.

scholarly journals PAICS contributes to gastric carcinogenesis and participates in DNA damage response by interacting with histone deacetylase 1/2

2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Nan Huang ◽  
Chang Xu ◽  
Liang Deng ◽  
Xue Li ◽  
Zhixuan Bian ◽  
...  
Keyword(s):  
Dna Damage ◽  
Histone Deacetylase ◽  
Dna Damage Response ◽  
De Novo ◽  
Dna Damage Repair ◽  
Histone Deacetylase 1 ◽  
Damage Repair ◽  
Damage Response

AbstractPhosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS), an essential enzyme involved in de novo purine biosynthesis, is connected with formation of various tumors. However, the specific biological roles and related mechanisms of PAICS in gastric cancer (GC) remain unclear. In the present study, we identified for the first time that PAICS was significantly upregulated in GC and high expression of PAICS was correlated with poor prognosis of patients with GC. In addition, knockdown of PAICS significantly induced cell apoptosis, and inhibited GC cell growth both in vitro and in vivo. Mechanistic studies first found that PAICS was engaged in DNA damage response, and knockdown of PAICS in GC cell lines induced DNA damage and impaired DNA damage repair efficiency. Further explorations revealed that PAICS interacted with histone deacetylase HDAC1 and HDAC2, and PAICS deficiency decreased the expression of DAD51 and inhibited its recruitment to DNA damage sites by impairing HDAC1/2 deacetylase activity, eventually preventing DNA damage repair. Consistently, PAICS deficiency enhanced the sensitivity of GC cells to DNA damage agent, cisplatin (CDDP), both in vitro and in vivo. Altogether, our findings demonstrate that PAICS plays an oncogenic role in GC, which act as a novel diagnosis and prognostic biomarker for patients with GC.

scholarly journals Anti-echinococcal effect of verapamil involving the regulation of the calcium/calmodulin-dependent protein kinase II response in vitro and in a murine infection model

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Hai-Jun Gao ◽  
Xu-Dong Sun ◽  
Yan-Ping Luo ◽  
Hua-Sheng Pang ◽  
Xing-Ming Ma ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mrna Expression ◽  
Echinococcus Granulosus ◽  
Calcium Content ◽  
Mrna Levels ◽  
Dependent Protein Kinase ◽  
Calcium Calmodulin Dependent ◽  
Dependent Protein

Abstract Background Echinococcosis, which is caused by the larvae of cestodes of the genus Echinococcus, is a parasitic zoonosis that poses a serious threat to the health of humans and animals globally. Albendazole is the drug of choice for the treatment of echinococcosis, but it is difficult to meet clinical goals with this chemotherapy due to its low cure rate and associated side effects after its long-term use. Hence, novel anti-parasitic targets and effective treatment alternatives are urgently needed. A previous study showed that verapamil (Vepm) can suppress the growth of Echinococcus granulosus larvae; however, the mechanism of this effect remains unclear. The aim of the present study was to gain insight into the anti-echinococcal effect of Vepm on Echinococcus with a particular focus on the regulatory effect of Vepm on calcium/calmodulin-dependent protein kinase II (Ca2+/CaM-CaMKII) in infected mice. Methods The anti-echinococcal effects of Vepm on Echinococcus granulosus protoscoleces (PSC) in vitro and Echinococcus multilocularis metacestodes in infected mice were assessed. The morphological alterations in Echinococcus spp. induced by Vepm were observed by scanning electron microscopy (SEM), and the changes in calcium content in both the parasite and mouse serum and liver were measured by SEM-energy dispersive spectrometry, inductively coupled plasma mass spectrometry and alizarin red staining. Additionally, the changes in the protein and mRNA levels of CaM and CaMKII in infected mice, and in the mRNA levels of CaMKII in E. granulosus PSC, were evaluated after treatment with Vepm by immunohistochemistry and/or real-time quantitative polymerase chain reaction. Results In vitro, E. granulosus PSC could be killed by Vepm at a concentration of 0.5 μg/ml or higher within 8 days. Under these conditions, the ultrastructure of PSC was damaged, and this damage was accompanied by obvious calcium loss and downregulation of CaMKII mRNA expression. In vivo, the weight and the calcium content of E. multilocularis metacestodes from mice were reduced after treatment with 40 mg/kg Vepm, and an elevation of the calcium content in the sera and livers of infected mice was observed. In addition, downregulation of CaM and CaMKII protein and mRNA expression in the livers of mice infected with E. multilocularis metacestodes was found after treatment with Vepm. Conclusions Vepm exerted a parasiticidal effect against Echinococcus both in vitro and in vivo through downregulating the expression of Ca2+/CaM-CaMKII, which was over-activated by parasitic infection. The results suggest that Ca2+/CaM-CaMKII may be a novel drug target, and that Vepm is a potential anti-echinococcal drug for the future control of echinococcosis.

scholarly journals Dephosphorylation of the C-terminal Tyrosyl Residue of the DNA Damage-related Histone H2A.X Is Mediated by the Protein Phosphatase Eyes Absent

2009 ◽  
Vol 284 (24) ◽  
pp. 16066-16070 ◽  
Author(s):  
Navasona Krishnan ◽  
Dae Gwin Jeong ◽  
Suk-Kyeong Jung ◽  
Seong Eon Ryu ◽  
Andrew Xiao ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Mammalian Cells ◽  
Protein Tyrosine Phosphatases ◽  
Histone H2a ◽  
Eyes Absent ◽  
Damage Repair ◽  
Damage Response

In mammalian cells, the DNA damage-related histone H2A variant H2A.X is characterized by a C-terminal tyrosyl residue, Tyr-142, which is phosphorylated by an atypical kinase, WSTF. The phosphorylation status of Tyr-142 in H2A.X has been shown to be an important regulator of the DNA damage response by controlling the formation of γH2A.X foci, which are platforms for recruiting molecules involved in DNA damage repair and signaling. In this work, we present evidence to support the identification of the Eyes Absent (EYA) phosphatases, protein-tyrosine phosphatases of the haloacid dehalogenase superfamily, as being responsible for dephosphorylating the C-terminal tyrosyl residue of histone H2A.X. We demonstrate that EYA2 and EYA3 displayed specificity for Tyr-142 of H2A.X in assays in vitro. Suppression of eya3 by RNA interference resulted in elevated basal phosphorylation and inhibited DNA damage-induced dephosphorylation of Tyr-142 of H2A.X in vivo. This study provides the first indication of a physiological substrate for the EYA phosphatases and suggests a novel role for these enzymes in regulation of the DNA damage response.

ADR1c mutations enhance the ability of ADR1 to activate transcription by a mechanism that is independent of effects on cyclic AMP-dependent protein kinase phosphorylation of Ser-230

1992 ◽  
Vol 12 (4) ◽  
pp. 1507-1514
Author(s):  
C L Denis ◽  
S C Fontaine ◽  
D Chase ◽  
B E Kemp ◽  
L T Bemis
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Transcriptional Activation ◽  
Growth Conditions ◽  
Dependent Protein Kinase ◽  
Inactive Form ◽  
Dependent Protein ◽  
Kinase Phosphorylation

Four ADR1c mutations that occur close to Ser-230 of the Saccharomyces cerevisiae transcriptional activator ADR1 and which greatly enhance the ability of ADR1 to activate ADH2 expression under glucose-repressed conditions have been shown to reduce or eliminate cyclic AMP-dependent protein kinase (cAPK) phosphorylation of Ser-230 in vitro. In addition, unregulated cAPK expression in vivo blocks ADH2 depression in an ADR1-dependent fashion in which ADR1c mutations display decreased sensitivity to unregulated cAPK activity. Taken together, these data have suggested that ADR1c mutations enhance ADR1 activity by blocking cAPK phosphorylation and inactivation of Ser-230. We have isolated and characterized an additional 17 ADR1c mutations, defining 10 different amino acid changes, that were located in the region defined by amino acids 227 through 239 of ADR1. Three observations, however, indicate that the ADR1c phenotype is not simply equivalent to a lack of cAPK phosphorylation. First, only some of these newly isolated ADR1c mutations affected the ability of yeast cAPK to phosphorylate corresponding synthetic peptides modeled on the 222 to 234 region of ADR1 in vitro. Second, we observed that strains lacking cAPK activity did not display enhanced ADH2 expression under glucose growth conditions. Third, when Ser-230 was mutated to a nonphosphorylatable residue, lack of cAPK activity led to a substantial increase in ADH2 expression under glucose-repressed conditions. Thus, while cAPK controls ADH2 expression and ADR1 is required for this control, cAPK acts by a mechanism that is independent of effects on ADR1 Ser-230. It was also observed that deletion of the ADR1c region resulted in an ADR1c phenotype. The ADR1c region is, therefore, involved in maintaining ADR1 in an inactive form. ADR1c mutations may block the binding of a repressor to ADR1 or alter the structure of ADR1 so that transcriptional activation regions become unmasked.

scholarly journals Cyclic AMP-dependent protein kinase inhibits the activity of myogenic helix-loop-helix proteins.

1992 ◽  
Vol 12 (10) ◽  
pp. 4478-4485 ◽  
Author(s):  
L Li ◽  
R Heller-Harrison ◽  
M Czech ◽  
E N Olson
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Transcriptional Activation ◽  
Consensus Sequence ◽  
Signal Transduction Pathway ◽  
Specific Gene ◽  
Dependent Protein Kinase ◽  
Dependent Protein

Differentiation of skeletal muscle cells is inhibited by the cyclic AMP (cAMP) signal transduction pathway. Here we report that the catalytic subunit of cAMP-dependent protein kinase (PKA) can substitute for cAMP and suppress muscle-specific transcription by silencing the activity of the MyoD family of regulatory factors, which includes MyoD, myogenin, myf5, and MRF4. Repression by the PKA catalytic (C) subunit is directed at the consensus sequence CANNTG, the target for DNA binding and transcriptional activation by these myogenic regulators. Phosphopeptide mapping of myogenin in vitro and in vivo revealed two PKA phosphorylation sites, both within the basic region. However, repression of myogenin function by PKA does not require direct phosphorylation of these sites but instead involves an indirect mechanism with one or more intermediate steps. Regulation of the transcriptional activity of the MyoD family by modulation of the cAMP signaling pathway may account for the inhibitory effects of certain peptide growth factors on muscle-specific gene expression and may also determine the responsiveness of different cell types to myogenic conversion by these myogenic regulators.

PEAK1 promotes invasion and metastasis and confers drug resistance in breast cancer

2021 ◽  
Author(s):  
xingang wang ◽  
YAN ZHENG ◽  
YU WANG
Keyword(s):  
Breast Cancer ◽  
Drug Resistance ◽  
Cell Growth ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Multi Drug Resistance ◽  
Cancer Tissues

Abstract Background and AimsPseudopodium-enriched atypical kinase 1 (PEAK1) has reported to be upregulated in human malignancies and related with poor prognosis. Enhanced PEAK1 expression facilitates tumor cell survival, invasion, metastasis and chemoresistance. However, the role of PEAK1 in breast cancer is not clear. Here, we investigated the PEAK1 expression in breast cancer and analyzed its relation with clinicopathological status and chemotherapy resistance to the neoadjuvant chemotherapy (NAC). We also investigated the role of PEAK1 on breast cancer cells in vitro and in vivo. MethodsImmunohistochemistry (IHC) was performed in 112 surgical resected breast cancer tissues. The associations between clinicopathological status, multi-drug resistance and PEAK1 expression were determined. Effect of PEAK1 overexpression or down-expression on proliferation, colony formation, invasion, migration, metastasis and Doxorubicin sensitivity in the MCF-7 cells in vitro and in vivo was detected. ResultsPEAK1 was overexpressed in breast cancer tissues and NAC -resistant breast cancer tissues. High PEAK1 expression was related with tumor size, high tumor grade, T stage, LN metastasis, recurrence, Ki-67 expression, Her-2 expression and multi-drug resistance. Targeting PEAK1 inhibited cell growth, invasion, metastasis and reversed chemoresistance to Doxorubicin in breast cancer cells in vitro and in vivo. ConclusionHigh PEAK1 expression was associated with invasion, metastasis and chemoresistance of breast cancers. Furthermore, targeting PEAK1 could inhibit cell growth and metastasis, and reverse chemoresistance in breast cancer cells, which provides an effective treatment strategies for breast cancer.

Cyclic AMP-dependent protein kinase inhibits the activity of myogenic helix-loop-helix proteins

1992 ◽  
Vol 12 (10) ◽  
pp. 4478-4485
Author(s):  
L Li ◽  
R Heller-Harrison ◽  
M Czech ◽  
E N Olson
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Transcriptional Activation ◽  
Consensus Sequence ◽  
Signal Transduction Pathway ◽  
Specific Gene ◽  
Dependent Protein Kinase ◽  
Dependent Protein

Differentiation of skeletal muscle cells is inhibited by the cyclic AMP (cAMP) signal transduction pathway. Here we report that the catalytic subunit of cAMP-dependent protein kinase (PKA) can substitute for cAMP and suppress muscle-specific transcription by silencing the activity of the MyoD family of regulatory factors, which includes MyoD, myogenin, myf5, and MRF4. Repression by the PKA catalytic (C) subunit is directed at the consensus sequence CANNTG, the target for DNA binding and transcriptional activation by these myogenic regulators. Phosphopeptide mapping of myogenin in vitro and in vivo revealed two PKA phosphorylation sites, both within the basic region. However, repression of myogenin function by PKA does not require direct phosphorylation of these sites but instead involves an indirect mechanism with one or more intermediate steps. Regulation of the transcriptional activity of the MyoD family by modulation of the cAMP signaling pathway may account for the inhibitory effects of certain peptide growth factors on muscle-specific gene expression and may also determine the responsiveness of different cell types to myogenic conversion by these myogenic regulators.

scholarly journals METTL3 promotes the initiation and metastasis of ovarian cancer by inhibiting CCNG2 expression via promoting the maturation of pri-microRNA-1246

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xuehan Bi ◽  
Xiao Lv ◽  
Dajiang Liu ◽  
Hongtao Guo ◽  
Guang Yao ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Molecular Mechanisms ◽  
High Expression ◽  
Ovarian Cancer Cells ◽  
Inadequate Knowledge ◽  
And Migration ◽  
Cancer Tissues

AbstractOvarian cancer is a common gynecological malignant tumor with a high mortality rate and poor prognosis. There is inadequate knowledge of the molecular mechanisms underlying ovarian cancer. We examined the expression of methyltransferase-like 3 (METTL3) in tumor specimens using RT-qPCR, immunohistochemistry, and Western blot analysis, and tested the methylation of METTL3 by MSP. Levels of METTL3, miR-1246, pri-miR-1246 and CCNG2 were then analyzed and their effects on cell biological processes were also investigated, using in vivo assay to validate the in vitro findings. METTL3 showed hypomethylation and high expression in ovarian cancer tissues and cells. Hypomethylation of METTL3 was pronounced in ovarian cancer samples, which was negatively associated with patient survival. Decreased METTL3 inhibited the proliferation and migration of ovarian cancer cells and promoted apoptosis, while METTL3 overexpression exerted opposite effects. Mechanistically, METTL3 aggravated ovarian cancer by targeting miR-1246, while miR-1246 targeted and inhibited CCNG2 expression. High expression of METTL3 downregulated CCNG2, promoted the metabolism and growth of transplanted tumors in nude mice, and inhibited apoptosis. The current study highlights the promoting role of METTL3 in the development of ovarian cancer, and presents new targets for its treatment.

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