Page 302 - 2014 Printable Abstract Book
P. 302
expression of usual targets (ER, PR and Her2/neu) therefore new therapeutic modalities are required to
increase overall survival of TNBC patients. Our hypothesis is based on the stimulation of the
cyclooxygenase-2 (COX-2) signalling pathway by ionizing radiation and the release of inflammatory
cytokines by healthy tissues which in turn trigger the stimulation of metastases development. We
previously showed that pre-irradiation of Balb/c mouse mammary gland enhanced the migration of D2A1
TNBC cells leading to an important increase of circulating tumor cells and lung metastases. These results
showed for the first time that inflammatory factors induced by irradiation of normal breast tissue is
playing a more important role than expected in breast cancer development. Presently, there is no clinical
modality allowing the prediction of the effects of ionizing radiation in patients. Our study is now focusing
on the validation of MT1-MMP, which favor the migration of cancer cells, as a biomarker to predict
radiation-induced metastases development. Our preliminary results suggest that the risk of metastases
development induced by radiation could be correlated to the level of MT1-MMP expression. Using pre-
clinical mouse model of TNBC, a single mammary gland was precisely irradiated with a GammaKnife with
four fractions of 6 Gy given at a 24h interval. After the last session of irradiation, irradiated and controls
mammary glands were implanted with D2A1cancer cells, either wild type or knockdown for MT1-MMP.
These D2A1 cells expressed the fluorescent gene FUCCI. Breast tumor invasion in the mammary gland was
monitored once a week by optical imaging over 3 weeks. Downregulation of MT1-MMP prevented
radiation-stimulation of cancer cell migration in the mammary gland and the development of lung
metastases. In conclusion, MT1-MMP could be a key factor in radiation-enhancement of metastases
development and a good biomarker to predict which TBNC patients are at higher risk to develop
metastases following radiotherapy.
(PS5-27) Total body irradiation induces extensive activation of tnf cascades and anoikis signaling in
2
2
1
1
intestines from non-human primates. Junying Zheng ; Junru Wang ; Mylene Pouliot ; Simon Authier ;
1
1;4
3
David Loose ; and Martin Hauer-Jensen ,University of Arkansas for Medical Sciences, Little Rock, AR ;
2
3
CiToxLAB North America, Laval, Canada ; UTHealth Medical School, Houston, TX ; and Central Arkansas
Veterans Healthcare System, Little Rock, AR
4
Background: Acute exposure to total body irradiation (TBI) damages the gastrointestinal (GI) tract,
causing progressive loss of crypt cells, villus atrophy, and breakdown of the epithelial barrier. To
understand the molecular mechanism of the injury, we compared the dynamic transcriptional profiles
from unirradiatied non-human primates (NHP) intestines with intestines from NHP exposed to TBI.
Methods: 28 males, young adult NHP (Rhesus macaque), without known preexisting disease underwent
sham-irradiation or exposure to 6.7Gy (LD70/30) or 7.4 Gy (LD90/30) TBI. Total RNA was extracted from
jejunum, ileum, and colon at 4d, 7d, and 12d after TBI and processed for DNA microarray analysis. Lists of
genes altered >=2-fold from jejunum, ileum and colon at each time point were generated by Genespring
GX and imported into Ingenuity Pathway Analysis (IPA) for upstream regulator analysis.
Results: TBI induced an extensive activation of TNF cascades at 4d in intestine. The ranking of activation
z-score (6.7Gy; 7.4Gy) from the highest to lowest was: colon (7.4; 9.2), jejunum (6.4, 5.6) and ileum (2.3;
3.8). Activation of TNF cascades was significantly suppressed at 7d and 12d in all gut sections. Of the TNF
downstream targets, genes mediating matrix degradation were markedly up-regulated after irradiation.
In jejunum, KLK3 and MMP12 were increased 54- and 18-fold after 6.7Gy TBI and 82-fold and 21-fold after
7.4Gy TBI. In colon, KLK10 and MMP7 were increased 27- and 11-fold after 6.7Gy and 52- and 41-fold after
7.4Gy TBI. The other increased genes for matrix degradation include MMP2, MMP9, etc. TBI also induced
300 | P a g e
increase overall survival of TNBC patients. Our hypothesis is based on the stimulation of the
cyclooxygenase-2 (COX-2) signalling pathway by ionizing radiation and the release of inflammatory
cytokines by healthy tissues which in turn trigger the stimulation of metastases development. We
previously showed that pre-irradiation of Balb/c mouse mammary gland enhanced the migration of D2A1
TNBC cells leading to an important increase of circulating tumor cells and lung metastases. These results
showed for the first time that inflammatory factors induced by irradiation of normal breast tissue is
playing a more important role than expected in breast cancer development. Presently, there is no clinical
modality allowing the prediction of the effects of ionizing radiation in patients. Our study is now focusing
on the validation of MT1-MMP, which favor the migration of cancer cells, as a biomarker to predict
radiation-induced metastases development. Our preliminary results suggest that the risk of metastases
development induced by radiation could be correlated to the level of MT1-MMP expression. Using pre-
clinical mouse model of TNBC, a single mammary gland was precisely irradiated with a GammaKnife with
four fractions of 6 Gy given at a 24h interval. After the last session of irradiation, irradiated and controls
mammary glands were implanted with D2A1cancer cells, either wild type or knockdown for MT1-MMP.
These D2A1 cells expressed the fluorescent gene FUCCI. Breast tumor invasion in the mammary gland was
monitored once a week by optical imaging over 3 weeks. Downregulation of MT1-MMP prevented
radiation-stimulation of cancer cell migration in the mammary gland and the development of lung
metastases. In conclusion, MT1-MMP could be a key factor in radiation-enhancement of metastases
development and a good biomarker to predict which TBNC patients are at higher risk to develop
metastases following radiotherapy.
(PS5-27) Total body irradiation induces extensive activation of tnf cascades and anoikis signaling in
2
2
1
1
intestines from non-human primates. Junying Zheng ; Junru Wang ; Mylene Pouliot ; Simon Authier ;
1
1;4
3
David Loose ; and Martin Hauer-Jensen ,University of Arkansas for Medical Sciences, Little Rock, AR ;
2
3
CiToxLAB North America, Laval, Canada ; UTHealth Medical School, Houston, TX ; and Central Arkansas
Veterans Healthcare System, Little Rock, AR
4
Background: Acute exposure to total body irradiation (TBI) damages the gastrointestinal (GI) tract,
causing progressive loss of crypt cells, villus atrophy, and breakdown of the epithelial barrier. To
understand the molecular mechanism of the injury, we compared the dynamic transcriptional profiles
from unirradiatied non-human primates (NHP) intestines with intestines from NHP exposed to TBI.
Methods: 28 males, young adult NHP (Rhesus macaque), without known preexisting disease underwent
sham-irradiation or exposure to 6.7Gy (LD70/30) or 7.4 Gy (LD90/30) TBI. Total RNA was extracted from
jejunum, ileum, and colon at 4d, 7d, and 12d after TBI and processed for DNA microarray analysis. Lists of
genes altered >=2-fold from jejunum, ileum and colon at each time point were generated by Genespring
GX and imported into Ingenuity Pathway Analysis (IPA) for upstream regulator analysis.
Results: TBI induced an extensive activation of TNF cascades at 4d in intestine. The ranking of activation
z-score (6.7Gy; 7.4Gy) from the highest to lowest was: colon (7.4; 9.2), jejunum (6.4, 5.6) and ileum (2.3;
3.8). Activation of TNF cascades was significantly suppressed at 7d and 12d in all gut sections. Of the TNF
downstream targets, genes mediating matrix degradation were markedly up-regulated after irradiation.
In jejunum, KLK3 and MMP12 were increased 54- and 18-fold after 6.7Gy TBI and 82-fold and 21-fold after
7.4Gy TBI. In colon, KLK10 and MMP7 were increased 27- and 11-fold after 6.7Gy and 52- and 41-fold after
7.4Gy TBI. The other increased genes for matrix degradation include MMP2, MMP9, etc. TBI also induced
300 | P a g e
