Evidence map›Paper›PMID 22867891›Full record

ArticleInternational journal of radiation oncology, biology, physics2012

Short hairpin RNA suppression of thymidylate synthase produces DNA mismatches and results in excellent radiosensitization.

Sheryl A Flanagan, Kristin S Cooper, Sudha Mannava, Mikhail A Nikiforov, Donna S Shewach

Abstract readComparative Study
In one paragraph

Article in International journal of radiation oncology, biology, physics, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
0.5field-weighted citation impact, top 35% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed, 5 citations in OpenAlex.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors at 2 institutions in 1 country.

Sheryl A FlanaganDepartment of Pharmacology, University of Michigan Medical Center, Ann Arbor, Michigan, USA. sflan@umich.edu
Kristin S Cooper
Sudha Mannava
Mikhail A Nikiforov
Donna S Shewach
University of Michigan–Ann Arbor · USRoswell Park Comprehensive Cancer Center · US

Funding

MICHIGAN INSTITUTE FOR CLINICAL AND HEALTH RESEARCH (MICHR) (UL1): (BPCA)UL1RR024986 · NCRR · UNIVERSITY OF MICHIGAN AT ANN ARBOR · PI SHANLEY, THOMAS P. · 2007 to 2011
$51.2M
Oncogene c-Myc-dependent pathways in cutaneous melanoma03R01CA120244 · NCI · UNIVERSITY OF MICHIGAN AT ANN ARBOR · PI NIKIFOROV, MIKHAIL · 2007 to 2016
$3.3M
Mechanisms of Cytotoxicity and Radiosensitization for AntimetabolitesR01CA083081 · NCI · UNIVERSITY OF MICHIGAN AT ANN ARBOR · PI SHEWACH, DONNA S. · 1999 to 2014
$3.2M
Enhancing Suicide Gene Therapy Through Mechanism-Based ApproachesR01CA076581 · NCI · UNIVERSITY OF MICHIGAN AT ANN ARBOR · PI SHEWACH, DONNA S. · 1998 to 2012
$2.8M
Enhancing Suicide Gene Therapy Through Mechanism-Based ApproachesR56CA076581 · NCI · UNIVERSITY OF MICHIGAN AT ANN ARBOR · PI SHEWACH, DONNA S. · 2007 to 2007
$285k
NCI NIH HHS CA076581NCI NIH HHS CA083081NCI NIH HHS R01 CA076581NCI NIH HHS R01 CA083081NCI NIH HHS R01 CA120244NCI NIH HHS R56 CA076581NCRR NIH HHS UL1 RR024986NCRR NIH HHS UL1RR024986
6 · The paper itself

Abstract

purposeTo determine the effect of short hairpin ribonucleic acid (shRNA)-mediated suppression of thymidylate synthase (TS) on cytotoxicity and radiosensitization and the mechanism by which these events occur. METHODS AND MATERIALS: shRNA suppression of TS was compared with 5-fluoro-2'-deoxyuridine (FdUrd) inactivation of TS with or without ionizing radiation in HCT116 and HT29 colon cancer cells. Cytotoxicity and radiosensitization were measured by clonogenic assay. Cell cycle effects were measured by flow cytometry. The effects of FdUrd or shRNA suppression of TS on dNTP deoxynucleotide triphosphate imbalances and consequent nucleotide misincorporations into deoxyribonucleic acid (DNA) were analyzed by high-pressure liquid chromatography and as pSP189 plasmid mutations, respectively.

resultsTS shRNA produced profound (≥ 90%) and prolonged (≥ 8 days) suppression of TS in HCT116 and HT29 cells, whereas FdUrd increased TS expression. TS shRNA also produced more specific and prolonged effects on dNTPs deoxynucleotide triphosphates compared with FdUrd. TS shRNA suppression allowed accumulation of cells in S-phase, although its effects were not as long-lasting as those of FdUrd. Both treatments resulted in phosphorylation of Chk1. TS shRNA alone was less cytotoxic than FdUrd but was equally effective as FdUrd in eliciting radiosensitization (radiation enhancement ratio: TS shRNA, 1.5-1.7; FdUrd, 1.4-1.6). TS shRNA and FdUrd produced a similar increase in the number and type of pSP189 mutations.

conclusionsTS shRNA produced less cytotoxicity than FdUrd but was equally effective at radiosensitizing tumor cells. Thus, the inhibitory effect of FdUrd on TS alone is sufficient to elicit radiosensitization with FdUrd, but it only partially explains FdUrd-mediated cytotoxicity and cell cycle inhibition. The increase in DNA mismatches after TS shRNA or FdUrd supports a causal and sufficient role for the depletion of dTTP thymidine triphosphate and consequent DNA mismatches underlying radiosensitization. Importantly, shRNA suppression of TS avoids FP-mediated TS elevation and its negative prognostic role. These studies support the further exploration of TS suppression as a novel radiosensitizing strategy.

Indexed as

DNA Mismatch RepairAdenosine TriphosphateAntimetabolites, AntineoplasticCell Line, TumorCheckpoint Kinase 1Cytidine TriphosphateEnzyme ActivationFloxuridineGuanosine TriphosphateHT29 CellsHumansPhosphorylationProtein KinasesRadiation ToleranceRNA, Small InterferingThymidylate SynthaseAdenosine TriphosphateAntimetabolites, AntineoplasticCheckpoint Kinase 1CHEK1 protein, humanCytidine TriphosphateFloxuridineGuanosine TriphosphateProtein KinasesRNA, Small InterferingThymidylate Synthase

Identifiers

PMID22867891
PMCPMC3494755
OpenAlexW2004933054

What OpenQuestion holds

Textmetadata
LicenceTDM
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.