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BackgroundGlioblastoma is a highly lethal neoplasm that frequently recurs locally after radiotherapy, and most of these recurrences originate from near the irradiated target field. In the present study, we identified the effects of radiation on glioma invasion and p53, TIMP-2, and MMP-2 expression through in vitro and in vivo experiments.MethodsThe U87MG (wt p53) and U251 (mt p53) human malignant glioma cell lines were prepared, and the U2OS (wt 53) and Saos2 (del p53) osteosarcoma cell lines were used as p53 positive and negative controls. The four cell lines and p53 knock-downed U87MG cells received radiation (2–6 Gy) and were analyzed for expression of p53 and TIMP-2 by Western blot, and MMP-2 activity was detected by zymography. In addition, the effects of irradiation on directional invasion of malignant glioma were evaluated by implanting nude mice with bioluminescent u87-Fluc in vivo followed by MMP-2, p53, and TIMP-2 immunohisto-chemistry and in situ zymography.ResultsMMP-2 activity and p53 expression increased in proportional to the radiation dose in cell lines with wt p53, but not in the cell lines with del or mt p53. TIMP-2 expression did not increase in U87MG cells. MMP-2 activity decreased in p53 knock-downed U87MG cells but increased in the control group. Furthermore, radiation enhanced MMP-2 activity and increased tumor margin invasiveness in vivo. Tumor cells invaded by radiation overexpressed MMP-2 and p53 and revealed high gelatinolytic activity compared with those of non-radiated tumor cells.ConclusionRadiation-induced upregulation of p53 modulated MMP-2 activity, and the imbalance between MMP-2 and TIMP-2 may have an important role in glioblastoma invasion by degrading the extracellular matrix. Bioluminescent “U87-Fluc”was useful for observing tumor formation without sacrifice after implanting tumor cells in the mouse brain. These findings suggest that the radiotherapy involved field for malignant glioma needs to be reconsidered, and that future trials should investigate concurrent pharmacologic therapies that inhibit invasion associated with radiotherapy.Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-015-0475-8) contains supplementary material, which is available to authorized users.

We report here the distribution of VNTRs (variable number of tandem repeats; minisatellites) and polymorphic analysis of SLC6A18, which is a member of the SLC6 Na(+)- and Cl(-)-dependent neurotransmitter transporter family. In this study, DNA was obtained from 300 unrelated individuals and 205 patients with essential hypertension (EH). We then analyzed the VNTRs in the genomic DNA by searching for minisatellites of SLC6A18 using the Tandem Repeat Finder program. Eight novel VNTRs were identified: five of which were polymorphic minisatellites (SLC6A18-MS1, -MS2, -MS4, -MS5, and -MS6) and three of which were monomorphic minisatellites (SLC6A18-MS3, -MS7, and -MS8). Next, we investigated the relationship between EH and four of the polymorphic minisatellites (SLC6A18-MS1, -MS2, -MS4, and -MS6). We excluded SLC6A18-MS5 from the common/rare allele analysis, because most individuals were heterozygous and hypervariable for this locus. There were no significant differences observed in the overall distribution of these minisatellites, which indicates that these polymorphisms are not responsible for EH susceptibility in the Korean population. A segregation analysis of the minisatellites in SLC6A18 was then conducted by analyzing genomic DNA obtained from two generations of five families and from three generations of two families. The five polymorphic minisatellites were transmitted through meiosis following Mendelian inheritance, which suggests that polymorphic minisatellites could be useful markers for paternity mapping and DNA fingerprinting. In summary, we discovered five novel VNTR polymorphisms in SLC6A18; however, these variations were not associated with EH.

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