Project description:This is a genome-wide approach to identifying genes persistently induced in the mouse mammary gland by acute whole body low dose ionizing radiation (10cGy), 1 and 4 weeks after exposure. Gene expression that is modified under these parameters were compared between Tgfb1 wild type and heterozygote littermates in order to determine which genes induced or repressed by radiation were mediated via Tgfb1 status. Differential gene expression was analyzed in Tgfb1 heterozygote and wild type littermate 4th mammary glands, after whole body exposure to an acute dose of 10cGy ionizing radiation. Estrus cycle was normalized in all mice two days prior to irradiation by injection with an estrogen and progesterone mixture. It is widely believed that the carcinogenic action of ionizing radiation is due to targeted DNA damage and resulting mutations, but there is also substantial evidence that non-targeted radiation effects alter epithelial phenotype and the stromal microenvironment. Activation of transforming growth factor beta 1 (TGFbeta) is a non-targeted radiation effect that mediates cell fate decisions following DNA damage and regulates microenvironment composition; it could either suppress or promote cancer. Gene expression profiling shown herein demonstrates that low dose radiation (10 cGy) elicits persistent changes in Tgfb1 wild type and heterozygote murine mammary gland that are highly modulated by TGFbeta. We asked if such non-targeted radiation effects contribute to carcinogenesis by using a novel radiation chimera model. Unirradiated Trp53 null mammary epithelium was transplanted to the mammary stroma of mice previously exposed to a single low (10 -100 cGy) radiation dose. By 300 days, 100% of transplants in irradiated hosts at either 10 or 100 cGy had developed Trp53 null breast carcinomas compared to 54% in unirradiated hosts. Tumor growth rate was also increased by high, but not low, dose host irradiation. In contrast, irradiation of Tgfb1 heterozygote mice prior to transplantation failed to decrease tumor latency, or increase growth rate at any dose. Host irradiation significantly reduced the latency of invasive ductal carcinoma compared to spindle cell carcinoma, as well as those tumors negative for smooth muscle actin in wild type but not Tgfb1 heterozygote mice. However, irradiation of either host genotype significantly increased the frequency of estrogen receptor negative tumors. These data demonstrate two concepts critical to understanding radiation risks. First, non-targeted radiation effects can significantly promote the frequency and alter the features of epithelial cancer. Second, radiation-induced TGFbeta activity is a key mechanism of tumor promotion. Keywords: Differential gene expression after low dose irradiation Two genotypes: TGBbeta1 heterozygote and wildtype mouse mammary glands. Two time points post-10cGy-irradiation per genotype (1 week, 4 weeks); control time point was 1 week post-sham-irradiation. Two or three replicates per time point.

Project description:Although various mechanisms have been inferred for combinatorial actions of multiple carcinogens, these mechanisms have not been well demonstrated in experimental carcinogenesis models. We evaluated mammary carcinogenesis initiated by combined exposure to various doses of radiation and chemical carcinogens. Female rats at 7 weeks of age were M-NM-3-irradiated (0.2M-bM-^@M-^S2 Gy) and/or exposed to 1-methyl-1-nitrosourea (20 or 40 mg/kg, single intraperitoneal injection) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (40 mg/kg/day by gavage for 10 days) and were observed until 50 weeks of age. The incidence of mammary carcinoma increased steadily as a function of radiation dose in the absence of chemicals; mathematical analysis supported an additive increase when radiation was combined with a chemical carcinogen, irrespective of the chemical species and its dose. Hras mutations were characteristic of carcinomas that developed after chemical carcinogen treatments and were overrepresented in carcinomas induced by the combination of radiation and MNU (but not PhIP), indicating an interaction of radiation and MNU at the level of initiation. The expression profiles of seven classifier genes, previously shown to distinguish two classes of rat mammary carcinomas, categorized almost all examined carcinomas that developed after individual or combined treatments with radiation (1 Gy) and chemicals as belonging to a single class; more comprehensive screening using microarrays and a separate test sample set failed to identify differences in gene expression profiles among these carcinomas. These results suggest that a complex, multilevel interaction underlies the combinatorial action of radiation and chemical carcinogens in the experimental model. Mammary cancers were from untreated rats (n = 3) and rats treated with radiation (1 Gy; n = 4), MNU (40 mg/kg; H-rasM-bM-^@M-^Smutated cancers, n = 5; H-rasM-bM-^@M-^Snonmutated cancers, n = 4), PhIP (H-rasM-bM-^@M-^Smutated, n = 1; H-rasM-bM-^@M-^Snonmutated, n = 3), radiation 1 Gy plus MNU (40 mg/kg; H-rasM-bM-^@M-^Smutated, n = 5; H-rasM-bM-^@M-^Snonmutated, n = 4) and radiation 1 Gy plus PhIP (H-rasM-bM-^@M-^Snonmutated , n = 4). Normal mammary tissues were from untreated rats (n = 3).

Project description:Background: Effective radiation treatment (RT) for recurrent nasopharyngeal cancers (NPC), featuring an intrinsic hypoxic sub-volume, remains a clinical challenge. Lack of disease‐specific in-vitro models, together with difficulties in establishing patient derived xenograft (PDX) models, have further hindered development of personalized therapeutic options. Methods: Here in, we established two NPC organoid lines from recurrent NPC PDX models and further characterized and compared these models with original patient tumors using RNA sequencing analysis. Organoids were cultured in hypoxic conditions to examine the effects of hypoxia and radioresistance. These models were then utilized to determine the radiobiological parameters, such as α/β ratio and oxygen enhancement ratio (OER), characteristic to radiosensitive normoxic and radioresistant hypoxic NPC, using simple dose-survival data analytic tools. The results were further validated in-vitro and in-vivo, to determine the optimal boost dose and fractionation regimen required to achieve effective NPC tumor regression. Results: Despite the differences in tumor microenvironment due to the lack of human stroma, RNA sequencing analysis revealed good correlation of NPC PDX and organoid models with patient tumors. Additionally, the established models also mimicked inter-tumoral heterogeneity. Hypoxic NPC organoids were highly radioresistant and had high α/β ratio compared to its normoxic counterparts. In-vitro and in-vivo fractionation studies showed that hypoxic NPC was less sensitive to RT fractionation scheme and required a large bolus dose or 1.4 times of the fractionated dose that was effective against normoxic cells in order to compensate for oxygen deficiency. Conclusion: This study is the first direct experimental evidence to predict optimal RT boost dose required to cause sufficient damage to recurrent hypoxic NPC tumor cells, which can be further used to develop dose-painting algorithms in clinical practice.

Project description:Densely ionizing radiation is a major component of the space radiation environment and has potentially greater carcinogenic effect compared to sparsely ionizing radiation that is prevalent in the terrestrial environment. It is unknown to what extent the irradiated microenvironment contributes to the differential carcinogenic potential of densely ionizing radiation. To address this gap, 10-week old BALB/c mice were irradiated with 100 cGy sparsely ionizing g-radiation or 10, 30, or 80 cGy of densely ionizing, 350 MeV/amu Si particles and transplanted 3 days later with syngeneic Trp53 null mammary fragments. Tumor appearance was monitored for 600 days. Tumors arising in Si-particle irradiated mice had a shorter median time to appearance, grew faster and were more likely to metastasize. Most tumors arising in sham-irradiated mice were ER-positive, pseudo-glandular and contained both basal keratin 14 and luminal keratin 8/18 cells (designated K14/18), while most tumors arising in irradiated hosts were K8/18 positive (designated K18) and ER negative. Comparison of K18 vs K14/18 tumor expression profiles showed that genes increased in K18 tumors were associated with ERBB2 and KRAS while decreased genes overlapped with those down regulated in metastasis and by loss of E-cadherin. Consistent with this, K18 tumors grew faster than K14/18 tumors and more mice with K18 tumors developed lung metastases compared to mice with K14/18 tumors. However, K18 tumors arising in Si-particle irradiated mice grew even faster and were more metastatic compared to control mice. A K18 Si-irradiated host profile was enriched in genes involved in mammary stem cells, stroma, and Notch signaling. Thus systemic responses to densely ionizing radiation enriches for a ER-negative, K18-positive tumor, whose biology is more aggressive compared to similar tumors arising in non-irradiated hosts. Key Words: ionizing radiation; breast cancer; heavy ion radiation;initiation; promotion 3 different dose of Si were used. Total RNA was extracted from mammary tumors derived from transplantations of non-irradiated p53null mammary fragments into irradiated hosts. We analyzed a total of 45 Trp53-null tumors: 18 from sham-irradiated hosts, 9 from 10 cGy Si-irradiated hosts, 10 from 30 cGy Si-irradiated hosts, and 8 from irradiated hosts.

			Action	DRS
	SRR13175100.fastq.gz	Fastqsanger.gz
	SRR13175101.fastq.gz	Fastqsanger.gz
	SRR13175102.fastq.gz	Fastqsanger.gz
	SRR13175103.fastq.gz	Fastqsanger.gz
	SRR13175104.fastq.gz	Fastqsanger.gz

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Radiation dose-fractionation effects on immune modulation in murine mammary tumors

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