Short Title: Sex Specific Diff Lung Cancer

Responsible HRP Element: Space Radiation

Collaborating Org(s):

Funding Status: Active - Currently funded and in progress

Procurement Mechanism(s):

Directed

Aims:

 Aim 1)  To determine whether a sex difference exists for radiation induced lung cancers across all  available exposed populations.

  Aim 2) To address the issues of transferring risks from one exposed population (e.g., the  Japanese atomic bomb survivors) to another (i.e., the astronaut population).
 
  Aim 3) To evaluate the optimum ways for incorporating the sex-specific lung cancer risks into the NASA lifetime risk projection model.
 
 

Short Title: Gender Differences in Radiation-induced Lung Adenocarcinoma

Responsible HRP Element: Space Radiation

Collaborating Org(s):

Funding Status: Active - Currently funded and in progress

Procurement Mechanism(s):

Solicited

Aims:
Specific Aim 1: Determine whether there are sex differences in the incidence and
aggressiveness of lung adenocarcinomas after charged particle irradiation.

Aim 1A: Determine the incidence of lung cancer resulting from low LET radiation exposures
(137Cs [?-ray, 0.02 keV/?m]and proton exposures mimicking the 1972 Solar particle event [30-
180 MeV/n, 1.2-0.2 keV/μM]), and high LET exposures (28Si [600 MeV/n, 50.4 keV/μm] and 40Ca
[533 MeV/n, 107.7 keV/μm]) in male vs female BALB/c mice.

Aim 1B: Determine if there is a sex difference in the incidence of lung tumor aggressiveness
(invasion/metastasis) in the same irradiated cohorts in Aim 1a by pathologic interrogation.
Specific Aim 2: Characterize the lung tumors generated either spontaneously or by radiation
exposure at both the tissue and molecular level.

Specific Aim 2: Characterize the lung tumors generated either spontaneously or by radiation
exposure at both the tissue and molecular level.

Aim 2A: Determine if there are sex differences in the characterization of such tumors that may
point to underlying mechanisms for risk for carcinogenesis or aggressiveness of tumors via
transcriptomics and miRNA expression analysis of tumors. Confirm where possible the
molecular markers identified at the tissue level by histology and/or immune histochemistry.

Aim 2B: Determine if biomarker(s) based upon the appearance of circulating miRNA in plasma
or whether there are DNA copy number changes contained within circulating fragmented DNA
(cfDNA) that occur over time post-irradiation that are indicative of lung cancer risk from either
low vs. high LET radiation exposure.

Aim 2C: Determine if the appearance and extent of phosphotidyl serine on the exosomes found
in the blood of irradiated animals are a marker for lung cancer risk when examined over time
post-irradiation.

Specific Aim 3: Determine whether the FDA investigational new drug GC4419 can mitigate
spontaneous and radiation-induced lung cancer incidence in animals when exposed to
simulated GCR and SPE’s.

Aim 3A: Determine the incidence of lung cancer in mice when GC4419 is provided ad libitum
just before and for 20 weeks post-irradiation.

Aim 3B: Determine whether there are molecular changes (transcriptomics and miRNA
expression) in the lung tissues of irradiated animals without tumors as a function of time when
exposed to GC4419 or not vs unirradiated controls.

Aim 3C: Using the molecular signatures established in Aim 2, determine if GC4419 alters such
signatures that were indicative of either high vs. low LET radiation or tumor aggressiveness and
whether there is a correlation between GC4419 exposure, lung cancer incidence, and the
appearance of circulating, exosomal phosphotidyl serine.

Short Title: GCR, DNA repair and countermeasures

Responsible HRP Element: Space Radiation

Collaborating Org(s):

Funding Status: Active - Currently funded and in progress

Procurement Mechanism(s):

Solicited

Aims:

Aim 1. Removed from study.

Aim 2. To test the hypothesis that GCR exposure leads to a chronic DNA damage response in mouse lung and whether this can be abated with a dietary countermeasure, nicotinamide riboside. Sex, dose and radiation quality effects will be investigated.

Aim 3. To determine whether radiogenic tumors display a mutational signature indicative of a decline in the functional status of the DNA repair machinery as reflected in their mutational signature, thus establishing a functional link to tumorigenesis. This aim has been expanded from the original study to include a pilot experiment to determine fixed-dose sex-specific radiation effect ratios (RERs) for lung tumorigenesis. Sex, radiation quality, and countermeasure effects will be investigated.

Short Title: Ovarian cancer and space radiation

Responsible HRP Element: Space Radiation

Collaborating Org(s):

Funding Status: Active - Currently funded and in progress

Procurement Mechanism(s):

Solicited

Aims:
Specific Aim 1: Utilize archived ovaries to compare ovarian tumor induction by irradiation with oxygen (16O), iron (56Fe), or g-rays and investigate the mouse strain dependence of ovarian tumor induction by 16O and 56Fe. Comparison of ovarian tumorigenesis in 3-month old C57BL/6J and B6C3F1 mice irradiated with 0.5 Gy 16O or 56Fe with 3-4 month old CB6F1 mice irradiated with 0.4, 0.8, 1.2, or 1.6 Gy g-rays, and concurrent controls, all euthanized 15-16 months after irradiation. We will conduct detailed histopathology of ovaries and molecular characterization of tumors using immunostaining for tumor markers. We will establish the relative biological effectiveness of charged 16O or 56Fe compared to g-radiation for ovarian tumorigenesis.

Specific Aim 2: Utilize archived ovaries harvested at various time points after irradiation
with low doses of 16O or 56Fe to examine the persistence of ovarian oxidative lipid, protein,
and DNA damage, archived serum to measure a biomarker of ovarian reserve, and evaluate
these as potential early biomarkers of ovarian tumorigenesis. Our published work [Mishra et
al. 2016, Mishra et al. 2017] demonstrates oxidative damage and dose-dependent apoptotic
depletion of ovarian follicles after exposure to 0, 0.05, 0.3, and 0.5 Gy 16O or 56Fe, with estimated
ED50 for follicle depletion at one week after irradiation of 0.046 and 0.27 Gy, respectively. Serum
luteinizing hormone (LH) and follicle stimulating hormone (FSH) were significantly elevated in
0.5 Gy-irradiated mice 8wk after irradiation, consistent with loss of negative feedback due to
follicle depletion, but serum LH and FSH are not optimal serum markers of ovarian reserve
because they vary with estrous cycle stage and are secreted episodically, and we did not perform
immunohistochemical analyses of ovaries at 8 wk after irradiation. We will examine oxidative
lipid, protein, and DNA damage by immunostaining as potential biomarkers of ovarian tumor risk
in archived ovaries from mice euthanized 8 wk after irradiation with 16O and 56Fe. We will measure
Anti-Müllerian Hormone (AMH), a serum marker of ovarian reserve that is used clinically, in
archived serum from mice euthanized 1 wk and 15 months after irradiation.

Short Title: Radiation-Induced Estrogenic Response and Breast Cancer Risk

Responsible HRP Element: Space Radiation

Collaborating Org(s):

Funding Status: Active - Currently funded and in progress

Procurement Mechanism(s):

Solicited

Aims:
Specific Aim 1. Quantitatively compare effects of simulated GCR dose rates on mammary
tumor incidence and grade in APCMin/+ and PTEN+/- tumor model. While we demonstrate
intestinal tumorigenesis is independent of space radiation dose rate and high dose rate protons
increased mammary tumorigenesis, effects of space environment relevant GCR dose rates on
mammary tumorigenesis are yet to be defined. Our working hypothesis is that space radiation
increases mammary tumor frequency and grade with reduce latency period for tumorigenesis
irrespective of dose rates. To test the hypothesis, we will use female APCMin/+ and PTEN+/- mice
to score mammary tumor frequency, measure tumor size, and assess tumor grade after low dose
rate (chronic) simulated GCR. Results will be compared to high dose rate (acute) GCR exposures
and acute g radiation exposure will be used as base line reference.

Specific Aim 2. Characterize GCR dose rate effects on PER in relation to mammary
tumorigenesis.

Aim 2A. Define roles of PER in space radiation-induced mammary tumorigenesis. We
found that exposure to high dose rate protons led to increased systemic and local estrogenic
response. However, it is not yet known how GCR dose rate relevant to space environment affects
estrogen and ERa levels, which are critical for mammary tumorigenesis. Our working hypothesis
is that high and low dose rate GCR triggers similar PER to promote mammary tumorigenesis.
First, we shall determine the extent of systemic PER by measuring estrogen and its metabolites
in serum and urine respectively. Second, we also determine the extent of local PER in mammary
glands by assessing ERa and breast cancer associated signaling pathways. Third, we will use
normal and ovariectomized mice to determine roles of space radiation-induced PER in mammary
tumorigenesis.

Aim 2B. Determine dose rate effects on estrogen synthesis and metabolism. Our working
hypothesis is that irrespective of dose rate GCR triggers sustained activation of estrogen
synthesis in ovaries to promote systemic PER that promotes local PER in mammary glands. Our
strategy is to irradiate normal and ovariectomized mice to determine whether ovarian synthesis,
and/or altered estrogen metabolism is the source of increased estrogen, and whether local PER in
mammary glands is dependent/independent of ovarian estrogen.

Aim 2C. Does space radiation-induced PER modulate immune response to promote
mammary tumorigenesis? Although we demonstrate increased tumor associated macrophage
(TAM) in high dose rate g radiation-induced tumors, we are yet to determine GCR dose rate
effects on immune cell responses (immunophenotype of tumor infiltrating cells) that are key
factors in breast cancer development. Our working hypothesis is that both high and low dose rate
GCR triggers tumor promoting T cell responses in mammary glands. Using isolated T cells from
mammary tumors and peripheral blood, we shall determine to what extent GCR dose rate alters i)
Treg cell response, ii) Th1/Th2 polarization balance, and iii) M1/M2 macrophage polarization.

Specific Aim 3. Determine roles of SERM in countering space radiation-induced PER and
mammary tumorigenesis in APCMin/+. This aim will test the hypothesis that blocking radiationinduced PER will reduce space radiation-induced mammary tumorigenesis. The strategy will be to treat mice with an SERM, which is FDA approved for breast cancer chemoprevention in both pre- and post-menopausal women, before exposure to whole-body irradiation and quantitatively and qualitatively assess PER and mammary gland tumorigenesis. This aim will test causal relationship between chronic GCR-induced PER and mammary tumorigenesis and compare the data with acute GCR and g-rays.

Specific Aim 4. Risk assessment of mammary tumorigenesis after space radiation exposure.
The overall hypothesis is that RBE of PER and mammary tumorigenesis between acute and
chronic GCR is similar but higher relative to g-rays. We further hypothesize that the differences
in RBE of tumorigenesis between GCR and g-rays will be reflected in carcinogenic precursor
signaling events thus providing a molecular foundation to tumorigenic risk estimates of space
radiation. This aim will use acquired quantitative and qualitative experimental data from Aim 1
to 3 to calculate RBE of mammary tumorigenesis, which can then be used to model human risk
estimation as well as risk mitigation.