Substituted Piperazines as Novel Potential Radioprotective Agents

The increasing risk of radiation exposure underlines the need for novel radioprotective agents. Hence, a series of novel 1-(2-hydroxyethyl)piperazine derivatives were designed and synthesized. Some of the compounds protected human cells against radiation-induced apoptosis and exhibited low cytotoxicity. Compared to the previous series of piperazine derivatives, compound 8 exhibited a radioprotective effect on cell survival in vitro and low toxicity in vivo. It also enhanced the survival of mice 30 days after whole-body irradiation (although this increase was not statistically significant). Taken together, our in vitro and in vivo data indicate that some of our compounds are valuable for further research as potential radioprotectors.

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DR5 Knockout Mice Are Compromised in Radiation-Induced Apoptosis

Molecular and Cellular Biology ◽

10.1128/mcb.25.5.2000-2013.2005 ◽

2005 ◽

Vol 25 (5) ◽

pp. 2000-2013 ◽

Cited By ~ 77

Author(s):

Niklas Finnberg ◽

Joshua J. Gruber ◽

Peiwen Fei ◽

Dorothea Rudolph ◽

Anka Bric ◽

...

Keyword(s):

Cell Death ◽

Null Mouse ◽

Organ Specific ◽

Radiation Induced ◽

Induced Apoptosis ◽

The Brain ◽

Necrosis Factor

ABSTRACT DR5 (also called TRAIL receptor 2 and KILLER) is an apoptosis-inducing membrane receptor for tumor necrosis factor-related apoptosis-inducing ligand (also called TRAIL and Apo2 ligand). DR5 is a transcriptional target of p53, and its overexpression induces cell death in vitro. However, the in vivo biology of DR5 has remained largely unexplored. To better understand the role of DR5 in development and in adult tissues, we have created a knockout mouse lacking DR5. This mouse is viable and develops normally with the exception of having an enlarged thymus. We show that DR5 is not expressed in developing embryos but is present in the decidua and chorion early in development. DR5-null mouse embryo fibroblasts expressing E1A are resistant to treatment with TRAIL, suggesting that DR5 may be the primary proapoptotic receptor for TRAIL in the mouse. When exposed to ionizing radiation, DR5-null tissues exhibit reduced amounts of apoptosis compared to wild-type thymus, spleen, Peyer's patches, and the white matter of the brain. In the ileum, colon, and stomach, DR5 deficiency was associated with a subtle phenotype of radiation-induced cell death. These results indicate that DR5 has a limited role during embryogenesis and early stages of development but plays an organ-specific role in the response to DNA-damaging stimuli.

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Phosphorylation of the Mdm2 oncoprotein by the c-Abl tyrosine kinase regulates p53 tumor suppression and the radiosensitivity of mice

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1611798114 ◽

2016 ◽

Vol 113 (52) ◽

pp. 15024-15029 ◽

Cited By ~ 5

Author(s):

Michael I. Carr ◽

Justine E. Roderick ◽

Hong Zhang ◽

Bruce A. Woda ◽

Michelle A. Kelliher ◽

...

Keyword(s):

Bone Marrow ◽

Dna Damage ◽

Tumor Suppression ◽

Bone Marrow Failure ◽

Genotoxic Stress ◽

Whole Body ◽

Atm Kinase ◽

Radiation Induced

The p53 tumor suppressor acts as a guardian of the genome by preventing the propagation of DNA damage-induced breaks and mutations to subsequent generations of cells. We have previously shown that phosphorylation of the Mdm2 oncoprotein at Ser394 by the ATM kinase is required for robust p53 stabilization and activation in cells treated with ionizing radiation, and that loss of Mdm2 Ser394 phosphorylation leads to spontaneous tumorigenesis and radioresistance in Mdm2S394A mice. Previous in vitro data indicate that the c-Abl kinase phosphorylates Mdm2 at the neighboring residue (Tyr393) in response to DNA damage to regulate p53-dependent apoptosis. In this present study, we have generated an Mdm2 mutant mouse (Mdm2Y393F) to determine whether c-Abl phosphorylation of Mdm2 regulates the p53-mediated DNA damage response or p53 tumor suppression in vivo. The Mdm2Y393F mice develop accelerated spontaneous and oncogene-induced tumors, yet display no defects in p53 stabilization and activity following acute genotoxic stress. Although apoptosis is unaltered in these mice, they recover more rapidly from radiation-induced bone marrow ablation and are more resistant to whole-body radiation-induced lethality. These data reveal an in vivo role for c-Abl phosphorylation of Mdm2 in regulation of p53 tumor suppression and bone marrow failure. However, c-Abl phosphorylation of Mdm2 Tyr393 appears to play a lesser role in governing Mdm2-p53 signaling than ATM phosphorylation of Mdm2 Ser394. Furthermore, the effects of these phosphorylation events on p53 regulation are not additive, as Mdm2Y393F/S394A mice and Mdm2S394A mice display similar phenotypes.

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BH3-only proteins Puma and Bim are rate-limiting for γ-radiation– and glucocorticoid-induced apoptosis of lymphoid cells in vivo

Blood ◽

10.1182/blood-2005-04-1595 ◽

2005 ◽

Vol 106 (13) ◽

pp. 4131-4138 ◽

Cited By ~ 186

Author(s):

Miriam Erlacher ◽

Ewa M. Michalak ◽

Priscilla N. Kelly ◽

Verena Labi ◽

Harald Niederegger ◽

...

Keyword(s):

Dna Damage ◽

Target Genes ◽

Cultured Cells ◽

Lymphoid Cells ◽

Whole Body ◽

Γ Radiation ◽

B Cell Leukemia ◽

Induced Apoptosis

Numerous p53 target genes have been implicated in DNA damage–induced apoptosis signaling, but proapoptotic Bcl-2 (B-cell leukemia 2) family members of the BH3 (Bcl-2 homolog region [BH] 3)–only subgroup appear to play the critical initiating role. In various types of cultured cells, 3 BH3-only proteins, namely Puma (p53 up-regulated modulator of apoptosis), Noxa, and Bim (Bcl-2 interacting mediator of cell death), have been shown to initiate p53-dependent as well as p53-independent apoptosis in response to DNA damage and treatment with anticancer drugs or glucocorticoids. In particular, the absence of Puma or Bim renders thymocytes and mature lymphocytes refractory to varying degrees to death induced in vitro by growth factor withdrawal, DNA damage, or glucocorticoids. To assess the in vivo relevance of these findings, we subjected mice lacking Puma, Noxa, or Bim to whole-body γ-radiation or the glucocorticoid dexamethasone and compared lymphocyte survival with that in wild-type and BCL2–transgenic mice. Absence of Puma or Bcl-2 overexpression efficiently protected diverse types of lymphocytes from the effects of γ-radiation in vivo, and loss of Bim provided lower but significant protection in most lymphocytes, whereas Noxa deficiency had no impact. Furthermore, both Puma and Bim were found to contribute significantly to glucocorticoid-induced killing. Our results thus establish that Puma and Bim are key initiators of γ-radiation– and glucocorticoid-induced apoptosis in lymphoid cells in vivo.

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TRIM21–SERPINB5 aids GMPS repression to protect nasopharyngeal carcinoma cells from radiation-induced apoptosis

10.1101/609743 ◽

2019 ◽

Author(s):

Panpan Zhang ◽

Xiaomin Li ◽

Qiuping He ◽

Lulu Zhang ◽

Keqing Song ◽

...

Keyword(s):

Nasopharyngeal Carcinoma ◽

Carcinoma Cells ◽

Head And Neck Malignancy ◽

Neck Malignancy ◽

Tripartite Motif ◽

Radiation Induced ◽

Induced Apoptosis ◽

Epistatic Analysis

AbstractNasopharyngeal carcinoma (NPC) is the most prevalent head and neck malignancy in South China and Southeast Asia. The main NPC treatment strategy is radiotherapy. However, recurrence resulting from radioresistance is a leading clinical bottleneck. Revealing the mechanism of NPC radioresistance would help improve the therapeutic effect. Here, our work reveals thatTRIM21(tripartite motif–containing 21) functions as an oncogene in NPC progression, and its ablation increases NPC cell radiosensitivity. Further analysis indicated that TRIM21 represses TP53 expression by mediating GMPS (guanine monophosphate synthase) ubiquitination and degradation after ionizing radiation. Mass spectrometry and co-immunoprecipitation showed that SERPINB5 (serpin family B member 5) interacts with both TRIM21 and GMPS. Epistatic analysis showed that SERPINB5 acts as an adaptor to recruit GMPS and introduce TRIM21 for ubiquitination. The in vitro and in vivo results validated the finding that SERPINB5 promotes NPC cell radioresistance. Furthermore, immunohistochemistry indicated that radioresistant patients have higher SERPINB5 expression. Overall, our data show that TRIM21–SERPINB5-mediated GMPS degradation facilitates TP53 repression, which promotes the radioresistance of NPC cells.

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PSP1, a Phosphatidylserine-Recognizing Peptide, Is Useful for Visualizing Radiation-Induced Apoptosis in Colorectal Cancer In Vitro and In Vivo

Translational Oncology ◽

10.1016/j.tranon.2018.06.008 ◽

2018 ◽

Vol 11 (4) ◽

pp. 1044-1052 ◽

Cited By ~ 1

Author(s):

Sang Mun Bae ◽

Soo Jung Park ◽

Myoungeun Choi ◽

Miyeoun Song ◽

Young Eun Cho ◽

...

Keyword(s):

Colorectal Cancer ◽

Radiation Induced ◽

Induced Apoptosis

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In Vitro and In Vivo Antioxidative Activity against Radiation-Induced Damage and the Systematic Chemical Components of Different Extracts of Lagotis brevituba Maxim

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2020/9726431 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Dan Zhang ◽

Lihong Tan ◽

Ling Yao ◽

Wei Tao ◽

Ruixue Gong ◽

...

Keyword(s):

Antioxidant Activity ◽

Antioxidant Activities ◽

Whole Body ◽

Chemical Components ◽

Control Group ◽

Dependent Manner ◽

Antioxidant Assays ◽

Radiation Induced

Lagotis brevituba Maxim is a perennial species distributed in the highlands of China, which has been used for more than 2000 years as a traditional Tibetan medicinal plant. However, no attention has been paid to the antioxidant activities of Lagotis brevituba Maxim in vitro or in vivo. Thus, this study aimed to evaluate the in vitro and in vivo antioxidant activity of Lagotis brevituba Maxim against radiation-induced damage as well as the systematic chemical components. To explore the relationship between the antioxidant activity and extraction solvent, Lagotis brevituba Maxim was extracted with three different solvents: methanol, water, and acetone. In antioxidant assays in vitro, the water extract had the strongest reducing power, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity compared with the methanol and acetone extracts. However, the methanol extract was more potent in the β-carotene/linoleic acid cooxidation assay. In antioxidant assays in vivo, mice that were exposed to 6.0 Gy60Co γ-ray whole-body radiation on day 15 after administration of Lagotis brevituba Maxim decreased their level of malondialdehyde (MDA) in a dose-dependent manner compared with the control group, indicating that Lagotis brevituba Maxim had favorable antioxidant activities in vivo. In addition, a total of 44 compounds were tentatively identified by liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS), including 19 flavonoids, 14 phenols, 8 phenylethanoid glycosides, 2 iridoid glycosides, and 1 carbohydrate. We obtained 25 compounds from plants in the genus Lagotis for the first time. These results suggested that Lagotis brevituba Maxim had potent antioxidant activity and could be explored as a novel natural antioxidant.

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Angiogenesis, Anti-Tumor, and Anti-Metastatic Activity of Novel α-Substituted Hetero-Aromatic Chalcone Hybrids as Inhibitors of Microtubule Polymerization

Frontiers in Chemistry ◽

10.3389/fchem.2021.766201 ◽

2021 ◽

Vol 9 ◽

Author(s):

Moran Sun ◽

Yuyang Wang ◽

Minghua Yuan ◽

Qing Zhao ◽

Yixin Zhang ◽

...

Keyword(s):

Angiogenesis Inhibitor ◽

Tube Formation ◽

Immunofluorescence Assay ◽

Migration And Invasion ◽

Tubulin Polymerization ◽

Low Cytotoxicity ◽

Induced Apoptosis ◽

Mcf 7

A library of new heteroaromatic ring-linked chalcone analogs were designed and synthesized of these, compound 7m with α-CH3 substitution and bearing a benzofuran ring, displaying the most potent activity, with IC50 values of 0.07–0.183 µM against three cancer cells. Its low cytotoxicity toward normal human cells and strong potency on drug-resistant cells revealed the possibility for cancer therapy. It also could moderately inhibit in vitro tubulin polymerization with an IC50 value of 12.23 µM, and the disruption of cellular architecture in MCF-7 cells was observed by an immunofluorescence assay. Cellular-based mechanism studies elucidated that 7m arrested the cell cycle at the G2/M phase and induced apoptosis by regulating the expression levels of caspases and PARP protein. Importantly, the compound 7 m was found to inhibit HUVEC tube formation, migration, and invasion in vitro. In vivo assay showed that 7m could effectively destroy angiogenesis of zebrafish embryos. Furthermore, our data suggested that treatment with 7m significantly reduced MCF-7 cell metastasis and proliferation in vitro and in zebrafish xenograft. Collectively, this work showed that chalcone hybrid 7m deserves further investigation as dual potential tubulin polymerization and angiogenesis inhibitor.

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Polyamine depletion inhibits irradiation-induced apoptosis in intestinal epithelia

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00564.2004 ◽

2005 ◽

Vol 289 (3) ◽

pp. G599-G606 ◽

Cited By ~ 19

Author(s):

Wenlin Deng ◽

Mary Jane Viar ◽

Leonard R. Johnson

Keyword(s):

Structural Damage ◽

Caspase 3 ◽

Intestinal Epithelial ◽

Γ Irradiation ◽

Intestinal Epithelia ◽

Proapoptotic Protein ◽

Radiation Induced ◽

Induced Apoptosis

Our group has previously shown that polyamine depletion delays apoptosis in rat intestinal epithelial (IEC-6) cells (Ray RM, Viar MJ, Yuan Q, and Johnson LR , Am J Physiol Cell Physiol 278: C480–C489, 2000). Here, we demonstrate that polyamine depletion inhibits γ-irradiation-induced apoptosis in vitro and in vivo. Pretreatment of IEC-6 cells with 5 mM α-difluoromethylornithine (DFMO) for 4 days significantly reduced radiation-induced caspase-3 activity and DNA fragmentation. This protective effect was prevented by the addition of 10 μM exogenous putrescine. Radiation exposure to mice resulted in a high frequency of apoptosis over cells positioned fourth to seventh in crypt-villus units. Pretreatment of mice with 2% DFMO in drinking water significantly reduced apoptotic cells from ∼2.75 to 1.61 per crypt-villus unit, accompanied by significant decreases in caspase-3 levels. Further examination showed that DFMO pretreatment inhibited the radiation-induced increase in the proapoptotic protein Bax. Moreover, DFMO pretreatment significantly enhanced the intestinal crypt survival rate by 2.1-fold subsequent to radiation and ameliorated mucosal structural damage. We conclude that polyamine depletion by DFMO inhibits γ-irradiation-induced apoptosis of intestinal epithelial cells both in vitro and in vivo through inhibition of Bax and caspase-3 activity, which leads to attenuation of radiation-inflicted intestinal injury. These data indicate that DFMO may be therapeutically useful to counteract the gastrointestinal toxicity caused by chemoradiotherapy. This is the first demonstration that polyamines are required for apoptosis in vivo.

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Use of Toxicokinetics in Risk Assessment Based on In Vitro Data

Alternatives to Laboratory Animals ◽

10.1177/026119299302100209 ◽

1993 ◽

Vol 21 (2) ◽

pp. 173-180

Author(s):

Gunnar Johanson

Keyword(s):

Risk Assessment ◽

Whole Body ◽

External Exposure ◽

Target Dose ◽

Toxic Response ◽

Route Of Exposure ◽

Vitro Data ◽

In Vitro Data

This presentation addresses some aspects of the methodology, advantages and problems associated with toxicokinetic modelling based on in vitro data. By using toxicokinetic models, particularly physiologically-based ones, it is possible, in principle, to describe whole body toxicokinetics, target doses and toxic effects from in vitro data. Modelling can be divided into three major steps: 1) to relate external exposure (applied dose) of xenobiotic to target dose; 2) to establish the relationship between target dose and effect (in vitro data, e.g. metabolism in microsomes, partitioning in tissue homogenates, and toxicity in cell cultures, are useful in both steps); and 3) to relate external exposure to toxic effect by combining the first two steps. Extrapolations from in vitro to in vivo, between animal and man, and between high and low doses, can easily be carried out by toxicokinetic simulations. In addition, several factors that may affect the toxic response by changing the target dose, such as route of exposure and physical activity, can be studied. New insights concerning the processes involved in toxicity often emerge during the design, refinement and validation of the model. The modelling approach is illustrated by two examples: 1) the carcinogenicity of 1,3-butadiene; and 2) the haematotoxicity of 2-butoxyethanol. Toxicokinetic modelling is an important tool in toxicological risk assessment based on in vitro data. Many factors, some of which can, and should be, studied in vitro, are involved in the expression of toxicity. Successful modelling depends on the identification and quantification of these factors.

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Adipocyte PHLPP2 inhibition prevents obesity-induced fatty liver

Nature Communications ◽

10.1038/s41467-021-22106-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

KyeongJin Kim ◽

Jin Ku Kang ◽

Young Hoon Jung ◽

Sang Bae Lee ◽

Raffaela Rametta ◽

...

Keyword(s):

Fatty Liver ◽

Whole Body ◽

Acid Oxidation ◽

Chow Diet ◽

Peroxisome Proliferator ◽

Obese Mice ◽

Ph Domain ◽

Peroxisome Proliferator Activated Receptor

AbstractIncreased adiposity confers risk for systemic insulin resistance and type 2 diabetes (T2D), but mechanisms underlying this pathogenic inter-organ crosstalk are incompletely understood. We find PHLPP2 (PH domain and leucine rich repeat protein phosphatase 2), recently identified as the Akt Ser473 phosphatase, to be increased in adipocytes from obese mice. To identify the functional consequence of increased adipocyte PHLPP2 in obese mice, we generated adipocyte-specific PHLPP2 knockout (A-PHLPP2) mice. A-PHLPP2 mice show normal adiposity and glucose metabolism when fed a normal chow diet, but reduced adiposity and improved whole-body glucose tolerance as compared to Cre- controls with high-fat diet (HFD) feeding. Notably, HFD-fed A-PHLPP2 mice show increased HSL phosphorylation, leading to increased lipolysis in vitro and in vivo. Mobilized adipocyte fatty acids are oxidized, leading to increased peroxisome proliferator-activated receptor alpha (PPARα)-dependent adiponectin secretion, which in turn increases hepatic fatty acid oxidation to ameliorate obesity-induced fatty liver. Consistently, adipose PHLPP2 expression is negatively correlated with serum adiponectin levels in obese humans. Overall, these data implicate an adipocyte PHLPP2-HSL-PPARα signaling axis to regulate systemic glucose and lipid homeostasis, and suggest that excess adipocyte PHLPP2 explains decreased adiponectin secretion and downstream metabolic consequence in obesity.

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