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Fig. 1.
FDG-PET as a means to visualize and quantify early
metabolic changes during VDA treatment. A: FDG-PET/MRI
images showing a PBS treated (control) and an OXi4503
treated tumor-bearing mice. Arrows indicate tumor
location. B: bar charts shows summarized data for all
treatments using SUV or reference-tissue-based
quantification of whole-tumor average or tumor sub-
volume glucose metabolism. Mean values ± SD are plotted.
P < 0.05; *, P < 0.001; **. C: scatterplot showing the close
relationship between PET-derived and Packard-derived
(ground truth) whole-tumor to whole-brain tracer ratios.
D: examples of high-resolution invasive analysis of the
intratumoral distribution of FDG retention.
Conclusion
Even though DCE-MRI and FDG-PET demonstrated
significant changes after treatment with VDAs, the
hyperpolarized ¹³C MRS AUC ratio and the lactate TTP did
not change. Further experiments including additional
tumor models and validation against established
technologies are needed to explore the usefulness of
hyperpolarized ¹³C MRS for early predicting of VDA
efficacy.
PV-0370 MicroRNA-200c radiosensitizes Human Cancer
Cells with Activated EGFR or HER2-associated Signaling
I.A. Kim
1
, T. Koo
2
, B. Cho
3
, E. Choi
3
, D. Lee
3
, H. Kim
3
, D.
Kim
3
, J. Park
3
1
Seoul National University School of Medicine, Radiation
Oncology, Seoul, Korea Republic of
2
Seoul National University Graduate School of Medicine,
Radiation Oncology, Seoul, Korea Republic of
3
Seoul National Univ. Bundang Hospital, Medical Science
Research Institute, Seongnam- Gyeonggi-Do, Korea
Republic of
Purpose or Objective
A member of the miRNA-200 family, miRNA-200c (miR-
200c), recently was found to have tumor-suppressive
properties by inhibiting the epithelial-mesenchymal
transition (EMT) process in several cancers . miR-200c also
interacts with various cellular signaling molecules and
regulates many important signaling pathways. In the
present study, we investigated the radiosensitizing effect
of miR-200c and the mechanism of radiosensitization in a
panel of human cancer cell lines.
Material and Methods
To predict the potential targets of miR-200c, a microRNA
database was used for bioinformatics analysis. Malignant
glioma (U251), breast cancer (SKBR3, MDAMB468) and lung
carcinoma (A549) cell lines were obtained from the
American Type Culture Collection (ATCC, Manassas, VA,
USA). Cells were transfected with pre-miR-200c or control
pre-miRNA using siPORTNeoFX™ transfection reagent
(Ambion, Austin, TX, USA). Anti-miR-200c was mixed with
Opti-MEM (Invitrogen, Grand Island, NY, USA), incubated
and added directly to cells. RT-PCR was performed using
the Taqman miRNA reverse transcription kit and the Fast
Real-Time PCR System (Applied Biosystems, Carlsbad, CA,
USA).
Clonogenic
assay,
immunoblotting
and
immunocytochemisty was perfomed.
Results
Ectopic overexpression of miR-200c led to down-
regulation of p-AKT, p-EGFR, and p-HER2 and increased
the radiosensitivity of U251, A549, SKBR3, and MDA-MB-
468 cells. In contrast, a miR-200c inhibitor led to up-
regulation of p-AKT, p-EGFR, and p-HER2 and decreased
radiation-induced cell killing. miR-200c led to
persistent γH2AX foci formation and down-regulated
pDNA-PKcs expression. Autophagy and apoptosis were
major modes of cell death. Bioinformatics analysis
predicted that miR-200c could have association with
EGFR, AKT, MAPK, VEGFA, HIF1AN. We also confirmed that
miR-200c downregulated expression of VEGF, HIF-1α, and
MMP2. Overexpression of miR-200c inhibited invasion,
migration, and vascular tube formation. These were
associated with downregulation of E-cadherin and EphA2,
and up-regulation of N-cadherin. miR-200c showed no
observable cytotoxic effect on normal human fibroblasts
and normal human astrocytes.
Conclusion
Taken together, our data suggest that miR-200c is an
attractive target for improving the efficacy of
radiotherapy via unique modulation of the complex
regulatory network controlling cancer pro-survival
signaling and EMT.
PV-0371 Novel molecular radiobiology for
personalised prostate cancer radiotherapy
N. McDermott
1
, A. Meunier
1
, T. Jameson
2
, A. Mansour
2
,
C. Haynes
2
, A. Flores
2
, A. O'Callaghan
1
, L. Marignol
1
1
Trinity Centre for Health Sciences Discipline of
Radiation Therapy, Radiation Therapy, Dublin, Ireland
2
Mount Sinai School of Medicine, International Health,
New York, USA
Purpose or Objective
The integration of tumour-specific biological parameters
to the decision-making process is anticipated to overcome
the recognised limitations of the current risk stratification
system for prostate cancer and transform the practice of
radiation oncology. Molecular imaging techniques are
rapidly advancing our ability to assess the extent and
aggressiveness of prostate cancer. Differential analyses of
extensive genetic profiles of specimens have progressed
the use of genetic signatures from tumour tissue in
providing additional prognostic information. Adopting an
hypothesis-based approach to the identification of novel
radiobiology that can assist the personalisation of prostate
radiotherapy, we propose that that the signalling
pathways that regulate several cancer hallmarks and are
responsive to hypoxia, such as Notch and YB-1 regulate the
molecular response of cells to radiation.
Material and Methods
The analysis of a panel of 22Rv1 prostate cancer cells was
used to support the identification of novel biomarkers of
radioresistance. First, an isogenic model of
radioresistance was generated in 22Rv1 prostate cancer
cells through exposure to 30 x 2-Gy dose fractions. Second,
radioresistance was induced in 22Rv1 cells through
exposure to hypoxic conditions (0.5% O2, 24hrs). miRNA
profiling of these samples was performed and validated by