Page 282 - 2014 Printable Abstract Book
P. 282
(PS4-81) Tumor progression exhibits a nonlinear dependence on prior low-dose whole-body irradiation.
Chris Briggs, PhD; Swati Girdhani, PhD; Philip Hahnfeldt, PhD; and Lynn Hlatky, PhD, Center of Cancer
Systems Biology, GRI, Tufts University School of Medicine, Boston, MA
Although classically radiation has been considered in conjunction with carcinogenesis initiation,
it is now clear radiation is an important modulator of the progression phase of carcinogenesis. The goal
of this study is to determine how whole-body low-dose gamma exposure affects tumor progression, by
investigation of tumor formation and growth in pre-irradiated hosts. Human A549 lung cancer cells were
implanted in mice previously irradiated with either 0Gy (controls), 0.05Gy or 0.10Gy acute gamma
irradiation. An attenuated growth rate was demonstrated in the 0.05Gy pre-irradiated mice, with
comparisons to the growth rate in the 0.10Gy irradiated mice suggesting that the response is non-linear.
Following tumor growth, animals were sacrificed and the transcriptome profile of the pre-irradiated
mouse host stroma with compared to that of the human tumor xenograft cells. Total RNA was extracted
and analyzed on Illumina M6 mouse expression arrays and also on Illumina HT12 human expression arrays.
Molecular pathway analyses were performed with GeneSet Enrichment Analysis (GSEA) and Ingenuity
Platform Analysis (IPA). IPA analysis of the human array expression data identified 4 biofunctions
predicted to be decreased in the 0.05Gy group compared to non-irradiated controls and 2 of these were
related to inflammation (Z-scores < -2.0). GSEA also produced evidence of suppression of immune
response in the human tumor xenograft cells. In contrast, IPA analysis of the mouse array expression data
predicted 2 biofunctions related to inflammation to be increased in the 0.05Gy group (Z-scores >2.0).
This research was supported by the Office of Science (BER), US Department of Energy, under Award
Number DE-SC0002606 (to L. Hlatky).
(PS4-82) Accumulation of senescence-associated beta-galactosidase-positive cells in gamma-irradiated
1
1
1
1;2
1
normal human fibroblast. Junya Ishikawa ; Mika Ando ; Shihori Hinago ; Maki Mori ; Mitsuaki Ojima ;
1
and Michiaki Kai, Department of Environmental Health Sciences, Oita University of Nursing and Health
1
Sciences, Oita, Japan and 2.Department of Radiological Life Sciences, Hirosaki University Graduate School
2
of Health Sciences, Hirosaki, Japan
Introduction: Our previous works suggest that the process of mouse radiation-induced acute
myeloid leukemia would involve stem cell turnover in multistep leukemogenesis. To clarify this
hypothesis, it is needed to quantify the several biological events, including cell death, proliferation, DNA
damage and/or repair, mutation. The aim of this study is to quantitatively evaluate these several biological
events in irradiated human cells at early time points. We investigated the alteration of cell kinetics by
ionizing radiation, such as survival, cell cycle, generation of reactive oxygen species (ROS), double strand
breaks (DSB) and senescence, during 0-30 days after irradiation. Materials and Methods: The normal
human fibroblast cells, MRC-5, was cultured to be confluent in Eagle’s minimum essential medium which
containing 10% fetal bovine serum, 100 unit/ml penicillin, 100 μg/ml streptomycin, and irradiated total
dose 0-3 Gy by 137Cs gamma-ray (0.72 Gy/min). After irradiation, these cells were harvested, and were
analyzed about survival (Trypan-blue exclusion test), cell cycle (Ki67), intracellular ROS contents (CellROX
Green Reagent), DSB frequency (p53 binding protein 1 foci per cell) and expression of senescence marker
(Senescence associated beta-galactosidase). Results and Discussion: In this study, the number of survival
cells were transitory decreased at Day 1 after irradiation, and gradually increased in time-dependent
manner. Then, the Ki67-positive cells increased compared with non-irradiated group, and reached almost
280 | P a g e
Chris Briggs, PhD; Swati Girdhani, PhD; Philip Hahnfeldt, PhD; and Lynn Hlatky, PhD, Center of Cancer
Systems Biology, GRI, Tufts University School of Medicine, Boston, MA
Although classically radiation has been considered in conjunction with carcinogenesis initiation,
it is now clear radiation is an important modulator of the progression phase of carcinogenesis. The goal
of this study is to determine how whole-body low-dose gamma exposure affects tumor progression, by
investigation of tumor formation and growth in pre-irradiated hosts. Human A549 lung cancer cells were
implanted in mice previously irradiated with either 0Gy (controls), 0.05Gy or 0.10Gy acute gamma
irradiation. An attenuated growth rate was demonstrated in the 0.05Gy pre-irradiated mice, with
comparisons to the growth rate in the 0.10Gy irradiated mice suggesting that the response is non-linear.
Following tumor growth, animals were sacrificed and the transcriptome profile of the pre-irradiated
mouse host stroma with compared to that of the human tumor xenograft cells. Total RNA was extracted
and analyzed on Illumina M6 mouse expression arrays and also on Illumina HT12 human expression arrays.
Molecular pathway analyses were performed with GeneSet Enrichment Analysis (GSEA) and Ingenuity
Platform Analysis (IPA). IPA analysis of the human array expression data identified 4 biofunctions
predicted to be decreased in the 0.05Gy group compared to non-irradiated controls and 2 of these were
related to inflammation (Z-scores < -2.0). GSEA also produced evidence of suppression of immune
response in the human tumor xenograft cells. In contrast, IPA analysis of the mouse array expression data
predicted 2 biofunctions related to inflammation to be increased in the 0.05Gy group (Z-scores >2.0).
This research was supported by the Office of Science (BER), US Department of Energy, under Award
Number DE-SC0002606 (to L. Hlatky).
(PS4-82) Accumulation of senescence-associated beta-galactosidase-positive cells in gamma-irradiated
1
1
1
1;2
1
normal human fibroblast. Junya Ishikawa ; Mika Ando ; Shihori Hinago ; Maki Mori ; Mitsuaki Ojima ;
1
and Michiaki Kai, Department of Environmental Health Sciences, Oita University of Nursing and Health
1
Sciences, Oita, Japan and 2.Department of Radiological Life Sciences, Hirosaki University Graduate School
2
of Health Sciences, Hirosaki, Japan
Introduction: Our previous works suggest that the process of mouse radiation-induced acute
myeloid leukemia would involve stem cell turnover in multistep leukemogenesis. To clarify this
hypothesis, it is needed to quantify the several biological events, including cell death, proliferation, DNA
damage and/or repair, mutation. The aim of this study is to quantitatively evaluate these several biological
events in irradiated human cells at early time points. We investigated the alteration of cell kinetics by
ionizing radiation, such as survival, cell cycle, generation of reactive oxygen species (ROS), double strand
breaks (DSB) and senescence, during 0-30 days after irradiation. Materials and Methods: The normal
human fibroblast cells, MRC-5, was cultured to be confluent in Eagle’s minimum essential medium which
containing 10% fetal bovine serum, 100 unit/ml penicillin, 100 μg/ml streptomycin, and irradiated total
dose 0-3 Gy by 137Cs gamma-ray (0.72 Gy/min). After irradiation, these cells were harvested, and were
analyzed about survival (Trypan-blue exclusion test), cell cycle (Ki67), intracellular ROS contents (CellROX
Green Reagent), DSB frequency (p53 binding protein 1 foci per cell) and expression of senescence marker
(Senescence associated beta-galactosidase). Results and Discussion: In this study, the number of survival
cells were transitory decreased at Day 1 after irradiation, and gradually increased in time-dependent
manner. Then, the Ki67-positive cells increased compared with non-irradiated group, and reached almost
280 | P a g e
