Predominant contribution of the dose received from constituent heavy-ions in the induction of gastrointestinal tumorigenesis after simulated space radiation exposure.

Gastrointestinal (GI) cancer risk among astronauts after encountering galactic cosmic radiation (GCR) is predicted to exceed safe permissible limits in long duration deep-space missions. Current predictions are based on relative biological effectiveness (RBE) values derived from in-vivo studies using single-ion beams, while GCR is essentially a mixed radiation field composed of protons (H), helium (He), and heavy ions. Therefore, a sequentially delivered proton (H) → Helium (He) → Oxygen (O) → Silicon (Si) beam was designed to simulate simplified-mixed-field GCR (Smf-GCR), and Apc1638N/+ mice were total-body irradiated to sham or γ (157Cs) or Smf-GCR followed by assessment of GI-tumorigenesis at 150 days post-exposure. Further, GI-tumor data from equivalent doses of heavy-ions (i.e., 0.05 Gy of O and Si) in 0.5 Gy of Smf-GCR were compared to understand the contributions of heavy-ions in GI-tumorigenesis. The Smf-GCR-induced tumor and carcinoma count were significantly greater than γ-rays, and male preponderance for GI-tumorigenesis was consistent with our earlier findings. Comparison of tumor data from Smf-GCR and equivalent doses of heavy ions revealed an association between higher GI-tumorigenesis where dose received from heavy-ions contributed to > 95% of the total GI-tumorigenic effect observed after Smf-GCR. This study provides the first experimental evidence that cancer risk after GCR exposure could largely depend on doses received from constituent heavy-ions.

LSD1 activates a lethal prostate cancer gene network independently of its demethylase function.

Medical castration that interferes with androgen receptor (AR) function is the principal treatment for advanced prostate cancer. However, clinical progression is universal, and tumors with AR-independent resistance mechanisms appear to be increasing in frequency. Consequently, there is an urgent need to develop new treatments targeting molecular pathways enriched in lethal prostate cancer. Lysine-specific demethylase 1 (LSD1) is a histone demethylase and an important regulator of gene expression. Here, we show that LSD1 promotes the survival of prostate cancer cells, including those that are castration-resistant, independently of its demethylase function and of the AR. Importantly, this effect is explained in part by activation of a lethal prostate cancer gene network in collaboration with LSD1's binding protein, ZNF217. Finally, that a small-molecule LSD1 inhibitor-SP-2509-blocks important demethylase-independent functions and suppresses castration-resistant prostate cancer cell viability demonstrates the potential of LSD1 inhibition in this disease.

Rectal ulcer and pseudomalignant epithelial changes after prostate seed brachytherapy: A rare complication with a diagnostic pitfall.

BACKGROUND: Implant brachytherapy (IBT) is a well-recognized treatment modality for early stage prostate cancer. Rectal ulcer and rectourethral fistula complicating IBT may cause an alteration of the normal anatomic landmarks. In this context, pseudomalignant radiation-induced changes within prostatic epithelium may be misinterpreted as a primary rectal malignancy. Such challenging and misleading findings have not been described, and may not be recognized as such. MATERIALS AND METHODS: We present the clinical and pathologic aspects of two patients who underwent IBT for low stage prostate cancer that was complicated by deep rectal ulcer. Both patients underwent extensive palliative surgical resection for disease control. RESULTS: The histologic changes in both cases were noteworthy for extensive necrosis and inflammation of the prostate, associated with loss of recto-prostatic anatomical landmarks. Prostatic glands showed striking radiation-induced atypia and pseudomalignant epithelial changes extending to the rectal ulcer bed, with no residual viable tumor. The first patient had undergone a biopsy of the rectal ulcer bed that was misinterpreted as a rectal adenocarcinoma prior to surgery. The similarity between atypical glands of the biopsy and the benign prostatic tissue with radiation-induced atypia in resection specimen confirmed their benign nature. CONCLUSIONS: Deep rectal ulcer complicating IBT may lead to distortion of the normal recto-prostatic anatomical landmarks, resulting in detection of pseudo-malignant prostatic glands at the ulcer base. Such findings may be mistaken for a primary rectal malignancy in limited biopsy material if not familiar to the pathologist.

Genetic variation in one-carbon metabolism in relation to genome-wide DNA methylation in breast tissue from heathy women.

Single nucleotide polymorphisms (SNPs) in one-carbon metabolism genes and lifestyle factors (alcohol drinking and breast folate) may be determinants of whole-genome methylation in the breast. DNA methylation profiling was performed using the Illumina Infinium HumanMethylation450 BeadChip in 81 normal breast tissues from women undergoing reduction mammoplasty and no history of cancer. ANCOVA, adjusting for age, race and BMI, was used to identify differentially-methylated (DM) CpGs. Gene expression, by the Affymetrix GeneChip Human Transcriptome Array 2.0, was correlated with DM. Biological networks of DM genes were assigned using Ingenuity Pathway Analysis. Fifty-seven CpG sites were DM in association with eight SNPs in FTHFD, MTHFD1, MTHFR, MTR, MTRR, and TYMS (P <5.0 x 10-5); 56% of the DM CpGs were associated with FTHFD SNPs, including DM within FTHFD. Gene expression was negatively correlated with FTHFD methylation (r=-0.25, P=0.017). Four DM CpGs identified by SNPs in MTRR, MTHFR, and FTHFD were significantly associated with alcohol consumption and/or breast folate. The top biological network of DM CpGs was associated with Energy Production, Molecular Transportation, and Nucleic Acid Metabolism. This is the first comprehensive study of the association between SNPs in one-carbon metabolism genes and genome-wide DNA methylation in normal breast tissues. These SNPs, especially FTHFD, as well as alcohol intake and folate exposure, appear to affect DM in breast tissues of healthy women. The finding that SNPs in FTHFD and MTR are associated with their own methylation is novel and highlights a role for these SNPs as cis-methylation quantitative trait loci.

Relationships among folate, alcohol consumption, gene variants in one-carbon metabolism and p16INK4a methylation and expression in healthy breast tissues.

p16(INK4a) is a tumor suppressor gene, frequently hypermethylated in breast cancer; this epigenetic silencing of p16(INK4a) occurs early in carcinogenesis. The risk factors and functional consequences of p16(INK4a) methylation are unknown. Alcohol consumption, a breast cancer risk factor, impedes folate metabolism and may thereby alter gene methylation since folate plays a pivotal role in DNA methylation. In a cross-sectional study of 138 women with no history of breast cancer who underwent reduction mammoplasty, we studied breast cancer risk factors, plasma and breast folate concentrations, variation in one-carbon metabolism genes, p16(INK4a) promoter methylation and P16 protein expression. Logistic regression was used to estimate multivariable-adjusted odds ratios (OR) and 95% confidence intervals (CI). p16(INK4a) methylation was negatively correlated with P16 expression (r = -0.28; P = 0.002). Alcohol consumption was associated with lower breast folate (P = 0.03), higher p16(INK4a) promoter methylation (P = 0.007) and less P16 expression (P = 0.002). Higher breast folate concentrations were associated with lower p16(INK4a) promoter methylation (P = 0.06). Genetic variation in MTRR (rs1801394) and MTHFD1 (rs1950902) was associated with higher p16 (INK4a) promoter methylation (OR = 2.66, 95% CI: 1.11-6.42 and OR = 2.72, 95% CI: 1.12-6.66, respectively), whereas variation in TYMS (rs502396) was associated with less P16 protein expression (OR = 0.22, 95% CI: 0.05-0.99). Given that this is the first study to indicate that alcohol consumption, breast folate and variation in one-carbon metabolism genes are associated with p16(INK4a) promoter methylation and P16 protein expression in healthy tissues; these findings require replication.

The PPARγ agonist efatutazone increases the spectrum of well-differentiated mammary cancer subtypes initiated by loss of full-length BRCA1 in association with TP53 haploinsufficiency.

Peroxisome proliferator-activated receptor gamma (PPARγ) agonists have anticancer activity and influence cell differentiation. We examined the impact of the selective PPARγ agonist efatutazone on mammary cancer pathogenesis in a mouse model of BRCA1 mutation. Mice with conditional loss of full-length BRCA1 targeted to mammary epithelial cells in association with germline TP53 insufficiency were treated with efatutazone through the diet starting at age 4 months and were euthanized at age 12 months or when palpable tumor reached 1 cm(3). Although treatment did not reduce percentage of mice developing invasive cancer, it significantly reduced prevalence of noninvasive cancer and total number of cancers per mouse and increased prevalence of well-differentiated cancer subtypes not usually seen in this mouse model. Invasive cancers from controls were uniformly estrogen receptor α negative and undifferentiated, whereas well-differentiated estrogen receptor α-positive papillary invasive cancers appeared in efatutazone-treated mice. Expression levels of phosphorylated AKT and CDK6 were significantly reduced in the cancers developing in efatutazone-treated mice. Efatutazone treatment reduced rates of mammary epithelial cell proliferation and development of hyperplastic alveolar nodules and increased expression levels of the PPARγ target genes Adfp, Fabp4, and Pdhk4 in preneoplastic mammary tissue. Intervention efatutazone treatment in mice with BRCA1 deficiency altered mammary cancer development by promoting development of differentiated invasive cancer and reducing prevalence of noninvasive cancer and preneoplastic disease.

Modulation of fatty acid and bile acid metabolism by peroxisome proliferator-activated receptor α protects against alcoholic liver disease.

BACKGROUND: Chronic alcohol intake affects liver function and causes hepatic pathological changes. It has been shown that peroxisome proliferator-activated receptor α (PPARα)-null mice developed more pronounced hepatic changes than wild-type (WT) mice after chronic exposure to a diet containing 4% alcohol. The remarkable similarity between the histopathology of alcoholic liver disease (ALD) in Ppara-null model and in humans, and the fact that PPARα expression and activity in human liver are less than one-tenth of those in WT mouse liver make Ppara-null a good system to investigate ALD. METHODS: In this study, the Ppara-null model was used to elucidate the dynamic regulation of PPARα activity during chronic alcohol intake. Hepatic transcriptomic and metabolomic analyses were used to examine alterations of gene expression and metabolites associated with pathological changes. The changes triggered by alcohol consumption on gene expression and metabolites in Ppara-null mice were compared with those in WT mice. RESULTS: The results showed that in the presence of PPARα, 3 major metabolic pathways in mitochondria, namely the fatty acid ß-oxidation, the tricarboxylic acid cycle, and the electron transfer chain, were induced in response to a 2-month alcohol feeding, while these responses were greatly reduced in the absence of PPARα. In line with the transcriptional modulations of these metabolic pathways, a progressive accumulation of triglycerides, a robust increase in hepatic cholic acid and its derivatives, and a strong induction of fibrogenesis genes were observed exclusively in alcohol-fed Ppara-null mice. CONCLUSIONS: These observations indicate that PPARα plays a protective role to enhance mitochondrial function in response to chronic alcohol consumption by adaptive transcriptional activation and suggest that activation of this nuclear receptor may be of therapeutic value in the treatment for ALD.

Immunohistochemical expression of ERG in the molecular epidemiology of fatal prostate cancer study.

BACKGROUND: Gene fusions between the ERG transcription factor and the androgen-regulated gene TMPRSS2 occur in a subset of prostate cancers and contribute to transformation of prostatic epithelial cells. Prior reports have used fluorescence in situ hybridization (FISH) or quantitative PCR (QPCR) to determine the presence of TMPRSS2-ERG fusions or ERG expression, respectively. Recently, several groups have reported on immunohistochemistry (IHC) to measure ERG expression, which is much more readily performed in clinical practice. However, the prior studies examining ERG expression by IHC had small sample sizes or they failed to clarify the association of ERG protein expression with important clinico-pathological features or prostate cancer-specific mortality. METHODS: To address these deficits, we evaluated ERG expression by IHC in 208 radical prostatectomy samples from the Kaiser Permanente Molecular Epidemiology of Fatal Prostate Cancer (MEFPC) study, a case-control study of prostate cancer-specific mortality. RESULTS: Nuclear ERG expression was seen in neoplastic prostate epithelia in 49 of the samples (23.7%). ERG expression in tumor cells was associated with higher tumor stage (OR = 2.0, 95% confidence interval 1.0-4.0, P value = 0.04). ERG immunoreactivity was positively associated with prostate cancer-specific mortality, although the confidence interval was wide (OR = 1.9, 95% confidence interval 0.88-4.0, P value = 0.10). CONCLUSIONS: Our results demonstrate that ERG protein expression is readily quantifiable with an existing commercial antibody. Evaluating ERG protein expression may improve our ability to identify the subset of more aggressive, invasive prostate cancers.

Plasma IGF-1 and IGFBP-3 may be imprecise surrogates for breast concentrations: an analysis of healthy women.

We investigated insulin-like growth factor (IGF)-1 and IGF binding protein (IGFBP)-3 concentrations in histologically normal breast tissues and assessed their association with plasma concentrations, and breast cancer risk factors. IGF-1 and IGFBP-3 were assessed in plasma and breast tissues of 90 women with no history of any cancer and undergoing reduction mammoplasty. Pearson correlations and ANOVAs were used to describe plasma-breast associations and biomarker differences by breast cancer risk factors, respectively. Multivariable regression models were used to determine associations between risk factors, and breast IGF-1 and IGFBP-3. The mean age of the study sample was 37.3 years, 58 % were white, and generally these women were obese (mean BMI = 30.8 kg/m(2)). We observed no plasma-breast correlation for IGF-1, IGFBP-3, or IGF-1/IGFBP-3 (r = -0.08, r = 0.14, and r = 0.03, respectively; p-values >0.05). Through age- and BMI-adjusted analysis, BMI and years of oral contraceptive (OC) use were inversely associated with breast IGF-1 (p-values = 0.02 and 0.003, respectively) and age was associated with breast IGFBP-3 (p = 0.01), while breast IGF-1/IGFBP-3 was higher in blacks than whites (1.08 vs. 0.68, p = 0.04) and associated with age and BMI (p-values = 0.03 and 0.002, respectively). In multivariable-adjusted models, some breast cancer risk factors studied herein explained 24, 10, and 15 % of the variation in breast IGF-1, IGFBP-3, and IGF-1/IGFBP-3, respectively. While reasons for the lack of plasma-breast hormone correlations in these cancer-free women are unknown, several factors were shown to be associated with breast concentrations. The lack of correlation between blood and tissue IGF-1 and IGFBP-3 suggests that studies of breast cancer risk assessing blood IGF-1 and IGFBP-3 may have important limitations in understanding their role in breast carcinogenesis.

Expression of Stem Cell Markers in High-LET Space Radiation-Induced Intestinal Tumors in Apc1638N/+ Mouse Intestine.

Estimation of cancer risk among astronauts planning to undertake future deep-space missions requires understanding the quantitative and qualitative differences in radiogenic cancers after low- and high-LET radiation exposures. Previously, we reported a multifold higher RBE for high-LET radiation-induced gastrointestinal (GI) tumorigenesis in Apc1638N/+ mice. Using the same model system, i.e., Apc1638N/+ mice, here, we report qualitative differences in the cellular phenotype of low- and high-LET radiation-induced GI tumors. Stem cell (SC) phenotypes were identified using BMI1, ALDH1, CD133, DCLK1, MSI1, and LGR5 markers in low (γ-rays)- and high (56Fe)-LET radiation-induced and spontaneous tumors. We also assessed the expression of these markers in the adjacent normal mucosa. All six of these putative SC markers were shown to be overexpressed in tumors compared to the adjacent normal intestinal tissue. A differential SC phenotype for spontaneous and radiogenic intestinal tumors in Apc1638N/+ mice was observed, where the ALDH1, BMI1, CD133, MSI1, and DCLK1 expressing cells were increased, while LGR5 expressing cells were decreased in 56Fe-induced tumors compared to γ-ray-induced and spontaneous tumors. Furthermore, higher ß-catenin activation (marked by nuclear localization) was observed in 56Fe-induced tumors compared to γ and spontaneous tumors. Since differential tumor cell phenotype along with activated ß-catenin may very well affect malignant progression, our findings are relevant to understanding the higher carcinogenic risk of high-LET radiation. This study has implications for the assessment of GI-cancer risk among astronauts, as well as for the estimation of secondary cancer risk among patients receiving hadron therapy, considering that our results indicate increased stemness properties after radiation.

Telomere length variation in normal epithelial cells adjacent to tumor: potential biomarker for breast cancer local recurrence.

A better understanding of the risk of local recurrence (LR) will facilitate therapeutic decision making in the management of early breast cancers. In the present study, we investigated whether telomere length in the normal breast epithelial cells surrounding the tumor is predictive of breast cancer LR; 152 women who were diagnosed with breast cancer at the Lombardi Comprehensive Cancer Center were included in this nested case-control study. Cases (patients had LR) and controls (patients had no LR) were matched on year of surgery, age at diagnosis and type of surgery. Telomere fluorescent in situ hybridization was used to determine the telomere length using formalin fixed paraffin-embedded breast tissues. Small telomere length variation (TLV), defined as the coefficient variation of telomere lengths among examined cells, in normal epithelial cells adjacent to the tumor was significantly associated with a 5-fold (95% confidence interval = 1.2-22.2) increased risk of breast cancer LR. When the subjects were categorized into quartiles, a significant inverse dose-response relationship was observed with lowest versus highest quartile odds ratio of 15.3 (P(trend) = 0.012). Patients who had large TLV had significantly better 10 year recurrence free survival rate compared with patients who had small TLV (80 versus 33%). The present study revealed that TLV in normal epithelial cells adjacent to tumor is a strong predictor of breast cancer LR. If confirmed by future studies, TLV in normal epithelial cells adjacent to tumor has the potential to become a promising biomarker for predicting breast cancer LR after breast conserving surgery.

Heavy-ion radiation-induced colitis and colorectal carcinogenesis in Il10-/- mice display co-activation of ß-catenin and NF-κB signaling.

Space radiation-induced gastrointestinal (GI) cancer risk models for future interplanetary astronauts are being developed that primarily rely on quantitative animal model studies to assess radiation-quality effects of heavy-ion space radiation exposure in relation to γ-rays. While current GI-cancer risk estimation efforts are focused on sporadic GI-cancer mouse models, emerging in-vivo data on heavy-ion radiation-induced long-term GI-inflammation are indicative of a higher but undetermined risk of GI-inflammation associated cancers, such as colitis-associated cancer (CAC). Therefore, we aimed to assess radiation quality effects on colonic inflammation, colon cancer incidence, and associated signaling events using an in-vivo CAC model i.e., Il10-/- mice. Male Il10-/- mice (8-10 weeks, n = 12/group) were irradiated with either sham, γ-rays or heavy-ions (28Si or 56Fe), and histopathological assessments for colitis and CAC were conducted at 2.5 months post-exposure. qPCR analysis for inflammation associated gene transcripts (Ptges and Tgfb1), and in-situ staining for markers of cell-proliferation (phospho-histone H3), oncogenesis (active-ß-catenin, and cyclin D1), and inflammation (phospho-p65NF-κB, iNOS, and COX2) were performed. Significantly higher colitis and CAC frequency were noted after heavy-ion exposure, relative to γ and control mice. Higher CAC incidence after heavy-ion exposure was associated with greater activation of ß-catenin and NF-κB signaling marked by induced expression of common downstream inflammatory (iNOS and COX2) and pro-proliferative (Cyclin D1) targets. In summary, IR-induced colitis and CAC incidence in Il10-/- mice depends on radiation quality and display co-activation of ß-catenin and NF-κB signaling.

Non-steroidal anti-inflammatory drugs (NSAIDs) and breast cancer risk: differences by molecular subtype.

Use of non-steroidal anti-inflammatory drugs (NSAIDs) has been associated with reduced risk of breast cancer, though findings have been inconsistent. This inconsistency may result from differences in etiology for breast tumors of different subtypes. We examined the association between NSAID use and breast cancer characterized by molecular subtypes in a population-based case-control study in Western New York. Cases (n = 1,170) were women with incident, primary, histologically confirmed breast cancer. Controls (n = 2,115) were randomly selected from NY Department of Motor Vehicles records (<65 years) or Medicare rolls (≥ 65 years). Participants answered questions regarding their use of aspirin and ibuprofen in the year prior to interview and their use of aspirin throughout their adult life. Logistic regression models estimated odds ratios (OR) and 95% confidence intervals (95% CI). Recent and lifetime aspirin use was associated with reduced risk, with no differences by subtype. Recent use of ibuprofen was significantly associated with increased risk of ER+/PR+(OR 1.33, 95% CI: 1.09-1.62), HER2- (OR 1.27, 95% CI: 1.05-1.53), and p53- breast cancers (OR 1.28, 95% CI: 1.04-1.57), as well as luminal A or B breast cancers. These findings support the hypothesis of heterogeneous etiologies of breast cancer subtypes and that aspirin and ibuprofen vary in their effects.

Effects of dietary aspirin on high-LET radiation-induced prostaglandin E2 levels and gastrointestinal tumorigenesis in Apc1638N/+ mice.

Inevitable exposure to high-LET ionizing radiation (IR) present in galactic cosmic radiation (GCR) could enhance gastrointestinal (GI) cancer incidence among astronauts undertaking deep space exploration and GI-cancer mortality has been predicted to far exceed NASA's limit of < 3% REID (Radiation exposure-induced death) from cancer. Therefore, the development of countermeasure agents against high-LET radiation-induced GI cancer is needed to safeguard astronauts during and after an outer space mission. The cyclooxygenase-2/prostaglandin E2 (COX2/PGE2) mediated activation of pro-inflammatory and oncogenic signaling has been reported to play an important role in persistent inflammation and GI-tumorigenesis after high-LET radiation exposure. Therefore, aspirin, a well-known inhibitor of the COX/PGE2 pathway, was evaluated as a potential countermeasure against 28Si-induced PGE2 and tumorigenesis in Apc1638N/+, a murine model of human GI-cancer. Animals were fed either standard or aspirin supplemented diet (75, 150, or 300 mg/day of human equivalent dose) starting at the age of 4 weeks and continued till the end of the study, while mice were exposed to 28Si-ions (300 MeV/n; 69 keV/µm) at the age of 8 weeks. Serum PGE2 level, GI tumor size (>2mm2), number, and cluster (>5 adjoining tumors) were analyzed at 150 days post-exposure. Aspirin led to a significant reduction in PGE2 in a dose-dependent manner but did not reduce 28Si-induced GI tumorigenesis even at the highest (300 mg/day) dose. In summary, this study suggests that aspirin could reduce high-LET IR-induced pro-inflammatory PGE2 levels, however, lacks the ability to reduce high-LET IR-induced GI tumorigenesis in Apc1638N/+ mice.

Non-steroidal anti-inflammatory drug (NSAID) use and breast cancer risk in the Western New York Exposures and Breast Cancer (WEB) Study.

OBJECTIVE: Chronic inflammation is suspected to have a role in breast carcinogenesis. Results of studies of non-steroidal anti-inflammatory drugs (NSAIDs) and breast cancer have been inconsistent. Timing of exposure and analysis of individual NSAIDs should be considered. METHODS: We conducted a population-based case-control study in western New York State between 1996 and 2001. Cases, 35-79 years, had incident, primary, histologically confirmed breast cancer (n = 1,170). Controls (n = 2,115) were randomly selected from NY Department of Motor Vehicles records (<65 years) or Medicare rolls (>or=65 years). Participants were queried on use of aspirin, ibuprofen, and acetaminophen in the year prior and on aspirin during adulthood. Unconditional logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (95% CI). RESULTS: Recent aspirin use was inversely associated with breast cancer risk (adjusted OR 0.80, 95% CI: 0.68-0.94); the strongest reduction in risk was observed among those who took >or=2 pills/day on days that aspirin was taken (OR 0.74, 95% CI: 0.61-0. 90). Adult lifetime use was also associated with breast cancer risk (>10 days/month, adjusted OR 0.68, 95% CI: 0.46-1.00). Use of ibuprofen or acetaminophen was not associated with breast cancer. CONCLUSIONS: This is the first study to investigate the association of adult lifetime aspirin intake with breast cancer risk. Our findings provide evidence that aspirin use throughout a woman's life may confer some benefit.

Fractionated and Acute Proton Radiation Show Differential Intestinal Tumorigenesis and DNA Damage and Repair Pathway Response in ApcMin/+ Mice.

PURPOSE: Proton radiation is a major component of the radiation field in outer space and is used clinically in radiation therapy of resistant cancers. Although epidemiologic studies in atom bomb survivors and radiologic workers have established radiation as a risk factor for colorectal cancer (CRC), we have yet to determine the risk of CRC posed by proton radiation owing to a lack of sufficient human or animal data. The purpose of the current study was to quantitatively and qualitatively characterize differential effects of acute and fractionated high-energy protons on colorectal carcinogenesis. METHODS AND MATERIALS: We used ApcMin/+ mice, a well-studied CRC model, to examine acute versus fractionated proton radiation-induced differences in intestinal tumorigenesis and associated signaling pathways. Mice were exposed to 1.88 Gy of proton radiation delivered in a single fraction or in 4 equal daily fractions (0.47 Gy × 4). Intestinal tumor number and grade were scored 100 to 110 days after irradiation, and tumor and tumor-adjacent normal tissues were harvested to assess proliferative ß-catenin/Akt pathways and DNA damage response and repair pathways relevant to colorectal carcinogenesis. RESULTS: Significantly higher intestinal tumor number and grade, along with decreased differentiation, were observed after acute radiation relative to fractionated radiation. Acute protons induced upregulation of ß-catenin and Akt pathways with increased proliferative marker phospho-histone H3. Increased DNA damage along with decreased DNA repair factors involved in mismatch repair and nonhomologous end joining were also observed after exposure to acute protons. CONCLUSIONS: We show increased γH2AX, 53BP1, and 8-oxo-dG, suggesting that increased ongoing DNA damage along with decreased DNA repair factors and increased proliferative responses could be triggering a higher number of intestinal tumors after acute relative to fractionated proton exposures in ApcMin/+ mice. Taken together, our data suggest greater carcinogenic potential of acute relative to fractionated proton radiation.

Dual Targeting of EGFR and IGF1R in the TNFAIP8 Knockdown Non-Small Cell Lung Cancer Cells.

Aberrant regulation of EGFR is common in non-small cell lung carcinomas (NSCLC), and tumor resistance to targeted therapies has been attributed to emergence of other co-occurring oncogenic events, parallel bypass receptor tyrosine kinase pathways including IGF1R, and TNFα-driven adaptive response via NF-κB. TNFAIP8, TNFα-inducible protein 8, is an NF-κB-activated prosurvival and oncogenic molecule. TNFAIP8 expression protects NF-κB-null cells from TNFα-induced cell death by inhibiting caspase-8 activity. Here, we demonstrate that knockdown of TNFAIP8 inhibited EGF and IGF-1-stimulated migration in NSCLC cells. TNFAIP8 knockdown cells showed decreased level of EGFR and increased expression of sorting nexin 1 (SNX1), a key regulator of the EGFR trafficking through the endosomal compartments, and treatment with SNX1 siRNA partially restored EGFR expression in these cells. TNFAIP8 knockdown cells also exhibited downregulation of IGF-1-induced pIGF1R and pAKT, and increased expression of IGF-1-binding protein 3 (IGFBP3), a negative regulator of the IGF-1/IGF1R signaling. Consistently, treatment of TNFAIP8 knockdown cells with IGFBP3 siRNA restored pIGF1R and pAKT levels. TNFAIP8 knockdown cells had enhanced sensitivities to inhibitors of EGFR, PI3K, and AKT. Furthermore, IHC expression of TNFAIP8 was associated with poor prognosis in NSCLC. These findings demonstrate TNFAIP8-mediated regulation of EGFR and IGF1R via SNX1 and IGFBP3, respectively. We posit that TNFAIP8 is a viable, multipronged target downstream of the TNFα/NF-κB axis, and silencing TNFAIP8 may overcome adaptive response in NSCLC. IMPLICATIONS: TNFAIP8 and its effectors SNX1 and IGFBP3 may be exploited to improve the efficacy of molecular-targeted therapies in NSCLC and other cancers.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/5/1207/F1.large.jpg.

Loss of claudins-1 and -7 and expression of claudins-3 and -4 correlate with prognostic variables in prostatic adenocarcinomas.

Claudins, members of a large family of adherent junction proteins, regulate the integrity and function of tight junctions and influence tumorigenesis. Recent studies have shown that altered levels of the different claudins may be related to invasion and progression of carcinoma cells in several primary neoplasms. However, there is no reported study documenting the pattern of claudin expression in prostatic adenocarcinomas (PACs). Formalin-fixed paraffin-embedded sections from 141 PACs were immunostained by manual and automated methods on the Xmatrx (BioGenex, San Ramon, CA) using antihuman claudin-1, -3, -4, -5, and -7 antibodies (Zymed, San Francisco, CA). Membranous immunoreactivity for each protein was semiquantitatively scored in both the tumor and adjacent benign epithelium in each case. Results were correlated with clinicopathologic variables. Variable membranous positivity was noted in the adjacent benign glands for all 5 proteins in all cases. PACs showed variable membranous positivity ranging from decreased, similar to, and increased in relation to the adjacent benign epithelium for all claudins. Decreased expression of claudin-1 correlated with high tumor grade (P = .001) and biochemical disease recurrence (P = .01), whereas decreased claudin-7 correlated with high tumor grade (P < .0001). In contrast, expression of claudin-3 correlated with advanced stage tumors (P = .03) and recurrence (P = .02), and expression of claudin-4 correlated with advanced stage (P = .02). On multivariate analysis, advanced stage (P = .026) and decreased claudin-1 protein expression (P = .005) independently predicted disease recurrence. Immunohistochemical expression and prognostic significance of claudins are variable in PACs, with decreased expression of claudin-1 emerging as an independent prognostic variable warranting further study.

CD79a is heterogeneously expressed in neoplastic and normal myeloid precursors and megakaryocytes in an antibody clone-dependent manner.

CD79a, a component of the B-cell antigen receptor complex, can also be expressed in certain non-B-cell malignancies. The reported frequency of CD79a expression in acute myeloid leukemias (AML) ranges from 0% to 90%. We evaluated 39 bone marrow biopsy specimens (29 AML and 10 normal cases) using 5 different commercially available anti-CD79a monoclonal antibody (MoAb) clones. Of 7 acute promyelocytic leukemia (APL) cases, 6 (86%) stained for CD79a with clones HM47/A9 (Novocastra, Newcastle Upon Tyne, England) and HM57 (DAKO, Carpinteria, CA) but were negative with clones 11E3 (Novocastra), and JCB117 (DAKO). Half of 6 acute megakaryoblastic leukemia (AMKL) cases and normal megakaryocytes in 14 (67%) of 21 cases were immunoreactive using clone 11D10 (Novocastra). Approximately one third of non-APL/non-AMKL AML and myeloid precursors in normal marrow specimens stained with clones HM57 and 11D10. This heterogeneity of CD79a expression in AML, megakaryocytes, and myeloid precursors is MoAb clone-dependent, likely owing to different epitope detection, and may be of diagnostic usefulness.

Increased Transgenerational Intestinal Tumorigenesis in Offspring of Ionizing Radiation Exposed Parent APC1638N/+ Mice.

The purpose of the study was to assess transgenerational intestinal tumorigenic effects of low dose ionizing radiation employing a well-characterized mouse model of human colorectal cancer. Mice (6 to 8 weeks old APC1638N/+ mice; n=20 per study group) were exposed to whole-body 25 cGy x-rays and mated 2 days post-irradiation. Intestinal tumorigenesis in male and female F1 mice from No Parents Irradiated (NPI), Both Parents Irradiated (BPI), and Male Parent Irradiated (MPI) groups were compared 210 days after birth. Male and female Direct Parent Irradiated (DPI) groups were additional controls for male and female F1 groups respectively. Data showed higher intestinal tumor frequency (± standard error of the mean) in male and female F1 from BPI (male: 7.81 ± 0.91; female: 5.45 ± 0.36) as well as from MPI (male: 6.30 ± 0.33; female: 4.45 ± 0.33) mice relative to F1 from NPI mice (male: 4.2 ± 0.48; female: 3.35 ± 0.37). Compared to male and female DPI (male: 5.55 ± 0.40; female: 3.60 ± 0.22), tumor frequency in F1 mice of BPI and MPI, though higher, was not statistically significant except for DPI vs. BPI in male mice. Additionally, both BPI and MPI showed increased frequency of larger tumors relative to NPI. In summary, our observations demonstrated that the APC1638N/+ mice due to its low spontaneous tumor frequency could serve as an effective model to study risk of transgenerational carcinogenesis in gastrointestinal tissues after exposure to clinically relevant low doses of ionizing radiation.