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Xuanxuan Wang, Hai Liu, Liming Shi, Xiaoli Yu, Yanjun Gu, Xiaonan Sun
LncRNA in non-homologous end joining (NHEJ) pathway 1 (LINP1) is an lncRNA which promotes therapeutic resistance in triple-negative breast cancer (TNBC). However, the expression and function of LINP1 in cervical cancer is not yet well-understood. In this study, we evaluated the expression levels of LINP1 in tumor tissues and cell lines of cervical cancer. We found that LINP1 associates with NHEJ proteins (Ku80 and DNA-PKcs). LINP1 translocates from cytosol to nucleus in response to irradiation. In addition, LINP1 knockdown significantly increases the levels of cleaved caspase3 and PARP, leading to enhanced cell apoptosis after ionizing radiation (IR)...
March 12, 2018: Cell Cycle
Christoph Oing, Pierre Tennstedt, Ronald Simon, Jennifer Volquardsen, Kerstin Borgmann, Carsten Bokemeyer, Cordula Petersen, Ekkehard Dikomey, Kai Rothkamm, Wael Y Mansour
Here we report that BCL2 blocks DNA double strand break (DSB) repair via nonhomologous end-joining (NHEJ), through sequestration of KU80 protein outside the nucleus. We find that this effect is associated with a repair switch to the error-prone PARP1-dependent end-joining (PARP1-EJ). We present in-vitro proof-of-concept for therapeutic targeting of this switch using PARP inhibitor to specifically enhance the radiosensitivity of BCL2-overexpressing cells. Given its erroneous behavior, PARP1-EJ might allow for the accumulation of genetic alterations and tumor progression...
March 8, 2018: Cancer Letters
Alisa Dewan, Mengtan Xing, Marie Benner Lundbæk, Raquel Gago-Fuentes, Carole Beck, Per Arne Aas, Nina-Beate Liabakk, Siri Sæterstad, Khac Thanh Phong Chau, Bodil Merete Kavli, Valentyn Oksenych
To ensure genome stability, mammalian cells employ several DNA repair pathways. Nonhomologous DNA end joining (NHEJ) is the DNA repair process that fixes double-strand breaks throughout the cell cycle. NHEJ is involved in the development of B and T lymphocytes through its function in V(D)J recombination and class switch recombination (CSR). NHEJ consists of several core and accessory factors, including Ku70, Ku80, XRCC4, DNA ligase 4, DNA-PKcs, Artemis, and XLF. Paralog of XRCC4 and XLF (PAXX) is the recently described accessory NHEJ factor that structurally resembles XRCC4 and XLF and interacts with Ku70/Ku80...
March 2018: FEBS Open Bio
Raquel Gago-Fuentes, Mengtan Xing, Siri Sæterstad, Antonio Sarno, Alisa Dewan, Carole Beck, Stefano Bradamante, Magnar Bjørås, Valentyn Oksenych
DNA repair consists of several cellular pathways which recognize and repair damaged DNA. The classical nonhomologous DNA end-joining (NHEJ) pathway repairs double-strand breaks in DNA. It is required for maturation of both B and T lymphocytes by supporting V(D)J recombination as well as B-cell differentiation during class switch recombination (CSR). Inactivation of NHEJ factors Ku70, Ku80, XRCC4, DNA ligase 4, DNA-PKcs, and Artemis impairs V(D)J recombination and blocks lymphocyte development. Paralogue of XRCC4 and XLF (PAXX) is an accessory NHEJ factor that has a significant impact on the repair of DNA lesions induced by ionizing radiation in human, murine, and chicken cells...
March 2018: FEBS Open Bio
Hannes Juergens, Javier A Varela, Arthur R Gorter de Vries, Thomas Perli, Veronica J M Gast, Nikola Y Gyurchev, Arun S Rajkumar, Robert Mans, Jack T Pronk, John P Morrissey, Jean-Marc G Daran
While CRISPR-Cas9-mediated genome editing has transformed yeast research, current plasmids and cassettes for Cas9 and guide-RNA expression are species specific. CRISPR tools that function in multiple yeast species could contribute to the intensifying research on non-conventional yeasts. A plasmid carrying a pangenomic origin of replication and two constitutive expression cassettes, for Cas9 and a ribozyme-flanked gRNAs was constructed. Its functionality was tested by analyzing inactivation of the ADE2 gene in four yeast species...
February 9, 2018: FEMS Yeast Research
Benigno C Valdez, Yang Li, David Murray, Yan Liu, Yago Nieto, Richard E Champlin, Borje S Andersson
Combination of drugs that target different aspects of aberrant cellular processes is an efficacious treatment for hematological malignancies. Hypomethylating agents (HMAs) and inhibitors of poly(ADP-ribose) polymerases (PARPis) and histone deacetylases (HDACis) are clinically active anti-tumor drugs. We hypothesized that their combination would be synergistically cytotoxic to leukemia and lymphoma cells. Exposure of AML and lymphoma cell lines to the combination of the PARPi niraparib (Npb), the HMA decitabine (DAC) and the HDACi romidepsin (Rom) or panobinostat (Pano) synergistically inhibited cell proliferation by up to 70% via activation of the ATM pathway, increased production of reactive oxygen species, decreased mitochondrial membrane potential, and activated apoptosis...
January 9, 2018: Oncotarget
Liang Zhuang, Fei Liu, Ping Peng, Huihua Xiong, Hong Qiu, Xiugen Fu, Zhiping Xiao, Xiaoyuan Huang
Cisplatin chemotherapy in combination with radiotherapy is the primary therapeutic strategy for the treatment of cervical cancer; however, the underlying molecular mechanism for cisplatin radiosensitization remains unknown. The aim of the present study was to investigate the effect of Ku80, a DNA double-strand break (DSB) repair protein, on cisplatin radiosensitization in cervical cancer. The pre-established Ku80 suppression cervical cancer cell line HeLa/Ku80-siRNA and the normal HeLa cell line underwent 6 MV X-ray irradiation (6 Gy) individually or in combination with 5 µg/ml cisplatin treatment...
January 2018: Oncology Letters
Jakob Liermann, Patrick Naumann, Franco Fortunato, Thomas E Schmid, Klaus-Josef Weber, Jürgen Debus, Stephanie E Combs
Background: Chemoradiation of locally advanced non-metastatic pancreatic cancer can lead to secondary operability by tumor mass reduction. Here, we analyzed radiomodulating effects of oridonin and ponicidin in pancreatic cancer in vitro. Both agents are ent-kaurane diterpenoids, extracted from Isodon rubescens, a plant that is well known in Traditional Chinese Medicine. Cytotoxic effects have recently been shown in different tumor entities for both agents. Materials and methods: Pancreatic cancer cell lines AsPC-1, BxPC-3, Panc-1 and MIA PaCa-2 were pretreated with oridonin or ponicidin and irradiated with 2 Gy to 6 Gy...
December 2017: Radiology and Oncology
Hiroki Arai, Ryuichi Wada, Kousuke Ishino, Mitsuhiro Kudo, Eiji Uchida, Zenya Naito
Gastric cancer is the third major cause of cancer-related mortality in Japan. The aim of this study was to identify a factor implicated in the biology of gastric cancer by comprehensive protein profiling. Protein profiling was carried out by liquid chromatography-tandem mass spectrometry, using formalin-fixed paraffin-embedded specimens of 17 gastric cancer cases. Pathway analysis and orthogonal partial least square-discriminant analysis suggested the significant expression of ribonucleoproteins, heterogeneous nuclear ribonucleoproteins, interleukin binding factor 2 (ILF2), KU70 and KU80, which are involved in DNA damage response (DDR)...
January 5, 2018: International Journal of Oncology
Daniel R Premkumar, Esther P Jane, Swetha Thambireddy, Philip A Sutera, Jonathon M Cavaleri, Ian F Pollack
In the present study, we investigated the effect of CDK inhibitors (ribociclib, palbociclib, seliciclib, AZD5438 and dinaciclib) on malignant human glioma cells for cell viability, apoptosis, oxidative stress and mitochondrial function using various assays. None of the CDK inhibitors induced cell death at a clinically relevant concentration. However, low nanomolar concentrations of dinaciclib showed higher cytotoxic activity against Bcl-xL silenced cells in a time- and concentration-dependent manner. This effect was not seen with other CDK inhibitors...
December 14, 2017: Molecular Carcinogenesis
Irina Alimova, Angela M Pierce, Peter Harris, Andrew Donson, Diane K Birks, Eric Prince, Ilango Balakrishnan, Nicholas K Foreman, Marcel Kool, Lindsey Hoffman, Sujatha Venkataraman, Rajeev Vibhakar
Atypical teratoid rhabdoid tumor (ATRT) is an aggressive and malignant pediatric brain tumor. Polo-like kinase 1 ( PLK1 ) is highly expressed in many cancers and essential for mitosis. Overexpression of PLK1 promotes chromosome instability and aneuploidy by overriding the G2-M DNA damage and spindle checkpoints. Recent studies suggest that targeting PLK1 by small molecule inhibitors is a promising approach to tumor therapy. We investigated the effect of PLK1 inhibition in ATRT. Gene expression analysis showed that PLK1 was overexpressed in ATRT patient samples and tumor cell lines...
November 14, 2017: Oncotarget
Manabu Koike, Yasutomo Yutoku, Aki Koike
Molecularly targeted therapies have high specificity and significant cancer-killing effect. However, their antitumor effect might be greatly diminished by variation in even a single amino acid in the target site, as it occurs, for example, as a consequence of SNPs. Increasing evidence suggests that the DNA repair protein Ku80 is an attractive target molecule for the development of next-generation radiosensitizers for human cancers. However, the localization, post-translational modifications (PTMs), and complex formation of Ku80 have not been elucidated in canines...
December 2017: FEBS Open Bio
Yachen Zang, Laura E Pascal, Yibin Zhou, Xiaonan Qiu, Leizhen Wei, Junkui Ai, Joel B Nelson, Mingming Zhong, Boxin Xue, Shaoxiong Wang, Dongrong Yang, Li Lan, Yuxi Shan, Zhou Wang
ELL2 is an androgen-responsive gene that is expressed by prostate epithelial cells and is frequently down-regulated in prostate cancer. Deletion of Ell2 in the murine prostate induced murine prostatic intraepithelial neoplasia and ELL2 knockdown enhanced proliferation and migration in C4-2 prostate cancer cells. Here, knockdown of ELL2 sensitized prostate cancer cells to DNA damage and overexpression of ELL2 protected prostate cancer cells from DNA damage. Knockdown of ELL2 impaired non-homologous end joining repair but not homologous recombination repair...
February 28, 2018: Cancer Letters
Hiro Sato, Atsuko Niimi, Takaaki Yasuhara, Tiara Bunga Mayang Permata, Yoshihiko Hagiwara, Mayu Isono, Endang Nuryadi, Ryota Sekine, Takahiro Oike, Sangeeta Kakoti, Yuya Yoshimoto, Kathryn D Held, Yoshiyuki Suzuki, Koji Kono, Kiyoshi Miyagawa, Takashi Nakano, Atsushi Shibata
Accumulating evidence suggests that exogenous cellular stress induces PD-L1 upregulation in cancer. A DNA double-strand break (DSB) is the most critical type of genotoxic stress, but the involvement of DSB repair in PD-L1 expression has not been investigated. Here we show that PD-L1 expression in cancer cells is upregulated in response to DSBs. This upregulation requires ATM/ATR/Chk1 kinases. Using an siRNA library targeting DSB repair genes, we discover that BRCA2 depletion enhances Chk1-dependent PD-L1 upregulation after X-rays or PARP inhibition...
November 24, 2017: Nature Communications
Jie Zhang, Grace Shim, Sonia M de Toledo, Edouard I Azzam
The absorption of ionizing radiation by living cells can directly disrupt atomic structures, producing chemical and biological changes. It can also act indirectly through radiolysis of water, thereby generating reactive chemical species that may damage nucleic acids, proteins, and lipids. Together, the direct and indirect effects of radiation initiate a series of biochemical and molecular signaling events that may repair the damage or culminate in permanent physiological changes or cell death. In efforts to gain insight into the mechanisms underlying these effects, we observed a prominent upregulation of the Translationally Controlled Tumor Protein (TCTP) in low dose/low dose rate (137)Cs γ-irradiated cells that was associated with adaptive responses that reduced chromosomal damage to a level lower than what occurs spontaneously...
2017: Results and Problems in Cell Differentiation
Kalnisha Naidoo, Patty T Wai, Sarah L Maguire, Frances Daley, Syed Haider, Divya Kriplani, James Campbell, Hasan Mirza, Anita Grigoriadis, Andrew Tutt, Paul M Moseley, Tarek M A Abdel-Fatah, Stephen Yt Chan, Srinivasan Madhusudan, Emad A Rakha, Ian O Ellis, Christopher J Lord, Yinyin Yuan, Andrew R Green, Rachael Natrajan
Disruption of Cyclin Dependent Kinase 12 (CDK12) is known to lead to defects in DNA repair and sensitivity to platinum salts and poly(ADP-ribose) polymerase 1/2 inhibitors. However, CDK12 has also been proposed as an oncogene in breast cancer. We therefore aimed to assess the frequency and distribution of CDK12 protein expression by immunohistochemistry (IHC) in independent cohorts of breast cancer and correlate this with outcome and genomic status. We found that 21% of primary unselected breast cancers were CDK12 high, and 10...
November 13, 2017: Molecular Cancer Therapeutics
Karen Suárez-Larios, Ana-María Salazar-Martínez, Regina Montero-Montoya
A study was realized to ascertain whether eight selected pesticides would induce double strand breaks (DSB) in lymphocyte cultures and whether this damage would induce greater levels of proteins Rad51 participating in homologous recombination or of p-Ku80 participating in nonhomologous end joining. Only five pesticides were found to induce DSB of which only glyphosate and paraoxon induced a significant increase of p-Ku80 protein, indicating that nonhomologous end joining recombinational DNA repair system would be activated...
2017: Journal of Toxicology
Qiongyu Yan, Huiqin Zhu, Li Lan, Jing Yi, Jie Yang
Non-homologous end-joining (NHEJ)-mediated repair of DNA double-strand breaks (DSBs) requires the formation of a Ku70/Ku80/DNA-PKcs complex at the DSB sites. A previous study has revealed Ku80 cleavage by caspase-3 during apoptosis. However, it remains largely unknown whether and how Ku80 cleavage affects its function in mediating NHEJ-mediated DNA repair. Here we report that Ku80 can be cleaved by caspases-2 at D726 upon a transient etoposide treatment. Caspase-2-mediated Ku80 cleavage promotes Ku80/DNA-PKcs interaction as the D726A mutation diminished Ku80 interaction with DNA-PKcs, while a Ku80 truncate (Ku80 ΔC6) lacking all the 6 residues following D726 rescued the weakened Ku80/DNA-PKcs interaction caused by caspase-2 knockdown...
December 2017: DNA Repair
Sofia D'Abrantes, Sarah Gratton, Pamela Reynolds, Verena Kriechbaumer, Joseph McKenna, Stephen Barnard, Dave Clarke, Stanley W Botchway
Genomic deoxyribonucleic acid (DNA) is continuously being damaged by endogenous processes such as metabolism or by exogenous events such as radiation. The specific phosphorylation of histone H2AX on serine residue 139, described as γ-H2AX, is an excellent indicator or marker of DNA double-strand breaks (DSBs). The yield of γ-H2AX (foci) is shown to have some correlation with the dose of radiation or other DSB-causing agents. However, there is some discrepancy in the DNA DSB foci yield among imaging and other methods such as gel electrophoresis...
October 20, 2017: Radiation Research
Chandra Bhushan Prasad, Shyam Babu Prasad, Suresh Singh Yadav, Laxmi Kant Pandey, Sunita Singh, Satyajit Pradhan, Gopeshwar Narayan
PARP1 trapping at DNA lesion by pharmacological inhibitors has been exploited in several cancers exhibiting defects in DNA repair mechanisms. PARP1 hyperactivation is involved in therapeutic resistance in multiple cancers. The role of PARP1 in cervical cancer (CC) resistance and implication of PARP inhibitor is yet to be elucidated. Our data demonstrates significantly higher expression of PARP1 in primary cervical tumors and CC cell lines SiHa and ME180. Upon cisplatin treatment CC cells display significant overexpression of PARP1 and its hyperactivation...
October 9, 2017: Scientific Reports
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