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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.
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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.
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Colite , Neoplasias do Colo , Gastrite , Neoplasias Induzidas por Radiação , Camundongos , Masculino , Animais , NF-kappa B/metabolismo , Ciclina D1/genética , beta Catenina/genética , beta Catenina/metabolismo , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Colite/induzido quimicamente , Carcinogênese , Neoplasias do Colo/patologia , Inflamação/complicações , Neoplasias Induzidas por Radiação/genética , Gastrite/complicações , Camundongos Endogâmicos C57BL , Modelos Animais de DoençasRESUMO
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) â Helium (He) â Oxygen (O) â 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.
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Radiação Cósmica , Íons Pesados , Neoplasias Induzidas por Radiação , Exposição à Radiação , Voo Espacial , Camundongos , Masculino , Animais , Íons Pesados/efeitos adversos , Hélio , Radiação Cósmica/efeitos adversos , Neoplasias Induzidas por Radiação/etiologia , Neoplasias Induzidas por Radiação/patologia , Carcinogênese , PrótonsRESUMO
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.
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Radiação Cósmica , Dinoprostona , Animais , Aspirina , Carcinogênese , Dieta , CamundongosRESUMO
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.
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Quebras de DNA de Cadeia Dupla , Reparo de Erro de Pareamento de DNA , Neoplasias Intestinais/genética , Neoplasias Induzidas por Radiação/genética , Prótons/efeitos adversos , 8-Hidroxi-2'-Desoxiguanosina/metabolismo , Animais , Carcinogênese/genética , Diferenciação Celular , Proliferação de Células , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Ciclina D1/metabolismo , Reparo do DNA por Junção de Extremidades , Modelos Animais de Doenças , Fracionamento da Dose de Radiação , Feminino , Expressão Gênica , Genes APC , Histonas/metabolismo , Immunoblotting/métodos , Neoplasias Intestinais/patologia , Intestino Delgado/metabolismo , Intestino Delgado/efeitos da radiação , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias Induzidas por Radiação/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Doses de Radiação , Exposição à Radiação/efeitos adversos , Voo Espacial , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima/efeitos da radiação , beta Catenina/metabolismoRESUMO
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.
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Proteínas Reguladoras de Apoptose/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Neoplasias Pulmonares/genética , RNA Interferente Pequeno/farmacologia , Receptor IGF Tipo 1/metabolismo , Células A549 , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Receptores ErbB/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Receptor IGF Tipo 1/antagonistas & inibidores , Receptor IGF Tipo 1/genética , Transdução de Sinais , Nexinas de Classificação/genética , Nexinas de Classificação/metabolismoRESUMO
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.
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Neoplasias da Próstata/radioterapia , Doenças Retais/diagnóstico , Fístula Retal/diagnóstico , Úlcera/diagnóstico , Fístula Urinária/diagnóstico , Adenocarcinoma/diagnóstico , Adenocarcinoma/patologia , Idoso , Braquiterapia , Erros de Diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Próstata/patologia , Próstata/cirurgia , Neoplasias da Próstata/patologia , Neoplasias da Próstata/cirurgia , Doenças Retais/patologia , Fístula Retal/patologia , Neoplasias Retais/diagnóstico , Neoplasias Retais/patologia , Úlcera/patologia , Fístula Urinária/patologiaRESUMO
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.
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Redes Reguladoras de Genes , Histona Desmetilases/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias de Próstata Resistentes à Castração/enzimologia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Histona Desmetilases/antagonistas & inibidores , Histona Desmetilases/genética , Humanos , Hidrazinas/farmacologia , Masculino , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/genética , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/patologia , Sulfonamidas/farmacologia , Transativadores/genética , Transativadores/metabolismoRESUMO
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.
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Despite known age-related DNA methylation (aDNAm) changes in breast tumors, little is known about aDNAm in normal breast tissues. Breast tissues from a cross-sectional study of 121 cancer-free women, were assayed for genome-wide DNA methylation. mRNA expression was assayed by microarray technology. Analysis of covariance was used to identify aDNAm's. Altered methylation was correlated with expression of the corresponding gene and with DNA methyltransferase protein DNMT3A, assayed by immunohistochemistry. Publically-available TCGA-BRCA data were used for replication. 1,214 aDNAm's were identified; 97% with increased methylation, and all on autosomes. Sites with increased methylation were predominantly in CpG lslands and non-enhancers. aDNAm's with decreased methylation were generally located in intergenic regions, non-CpG Islands, and enhancers. Of the aDNAm's identified, 650 are known to be involved in cancer, including ESR1 and beta-estradiol responsive genes. Expression of DNMT3A was positively associated with age. Two aDNAm's showed borderline significant associations with DNMT3A expression; KRR1 (OR 6.57, 95% CI: 2.51-17.23) and DHRS12 (OR 6.08, 95% CI: 2.33-15.86). A subset of aDNAm's co-localized within vulnerable regions for somatic mutations in cancers including breast cancer. Expression of C19orf48 was inversely and significantly correlated with its methylation level. In the TCGA dataset, 84% and 64% of the previously identified aDNAm's were correlated with age in both normal-adjacent and tumor breast tissues, with differential associations by histological subtype. Given the similarity of findings in the breast tissues of healthy women and breast tumors, aDNAm's may be one pathway for increased breast cancer risk with age.
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BACKGROUND: Genome-wide miRNA expression may be useful for predicting breast cancer risk and/or for the early detection of breast cancer. RESULTS: A 41-miRNA model distinguished breast cancer risk in the discovery study (accuracy of 83.3%), which was replicated in the independent study (accuracy = 63.4%, P=0.09). Among the 41 miRNA, 20 miRNAs were detectable in serum, and predicted breast cancer occurrence within 18 months of blood draw (accuracy 53%, P=0.06). These risk-related miRNAs were enriched for HER-2 and estrogen-dependent breast cancer signaling. MATERIALS AND METHODS: MiRNAs were assessed in two cross-sectional studies of women without breast cancer and a nested case-control study of breast cancer. Using breast tissues, a multivariate analysis was used to model women with high and low breast cancer risk (based upon Gail risk model) in a discovery study of women without breast cancer (n=90), and applied to an independent replication study (n=71). The model was then assessed using serum samples from the nested case-control study (n=410). CONCLUSIONS: Studying breast tissues of women without breast cancer revealed miRNAs correlated with breast cancer risk, which were then found to be altered in the serum of women who later developed breast cancer. These results serve as proof-of-principle that miRNAs in women without breast cancer may be useful for predicting breast cancer risk and/or as an adjunct for breast cancer early detection. The miRNAs identified herein may be involved in breast carcinogenic pathways because they were first identified in the breast tissues of healthy women.
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Neoplasias da Mama/genética , MicroRNAs/fisiologia , Adulto , Idoso , Neoplasias da Mama/etiologia , Estudos de Casos e Controles , Estudos Transversais , Feminino , Perfilação da Expressão Gênica , Humanos , MicroRNAs/análise , Pessoa de Meia-Idade , RiscoRESUMO
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.
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Genome-wide DNA hypomethylation is an early event in the carcinogenic process. Percent methylation of long interspersed nucleotide element-1 (LINE-1) is a biomarker of genome-wide methylation and is a potential biomarker for breast cancer. Understanding factors associated with percent LINE-1 DNA methylation in histologically normal tissues could provide insight into early stages of carcinogenesis. In a cross-sectional study of 121 healthy women with no prior history of cancer who underwent reduction mammoplasty, we examined associations between plasma and breast folate, genetic variation in one-carbon metabolism, and percent LINE-1 methylation using multivariable regression models (adjusting for race, oral contraceptive use, and alcohol use). Results are expressed as the ratio of LINE-1 methylation relative to that of the referent group, with the corresponding 95% confidence intervals (CI). We found no significant associations between plasma or breast folate and percent LINE-1 methylation. Variation in MTHFR, MTR, and MTRR were significantly associated with percent LINE-1 methylation. Variant allele carriers of MTHFR A1289C had 4% lower LINE-1 methylation (Ratio 0.96, 95% CI 0.93-0.98), while variant allele carriers of MTR A2756G (Ratio 1.03, 95% CI 1.01-1.06) and MTRR A66G (Ratio 1.03, 95% CI 1.01-1.06) had 3% higher LINE-1 methylation, compared to those carrying the more common genotypes of these SNPs. DNA methylation of LINE-1 elements in histologically normal breast tissues is influenced by polymorphisms in genes in the one-carbon metabolism pathway. Future studies are needed to investigate the sociodemographic, environmental and additional genetic determinants of DNA methylation in breast tissues and the impact on breast cancer susceptibility.
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5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/genética , Metilação de DNA/genética , Ferredoxina-NADP Redutase/genética , Elementos Nucleotídeos Longos e Dispersos/genética , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Adulto , Alelos , Mama/metabolismo , Mama/patologia , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Carbono/metabolismo , Feminino , Ácido Fólico/metabolismo , Predisposição Genética para Doença , Humanos , Polimorfismo de Nucleotídeo Único , Fatores de RiscoRESUMO
Ionizing radiation is a known risk factor for gastrointestinal (GI) pathologies including cancer. Hormones and related signaling crosstalk, which could contribute to radiation-induced persistent pathophysiologic changes in the small intestine and colon, remain to be explored. The current study assessed perturbation of GI homeostasis-related hormones and signaling pathways at the systemic as well as at the tissue level in small intestine and colon. Mice (6-8 week old C57BL/6J) were exposed to 2 Gy γ radiation, serum and tissue samples were collected, and insulin like growth factor 1 (IGF-1) and leptin signaling were assessed two or twelve months after radiation exposure. Serum levels of IGF-1, IGF binding protein 3 (IGFBP3), leptin, and adiponectin were altered at these times after irradiation. Radiation was associated with increased IGF1 receptor (IGF1R) and obesity (leptin) receptor (Ob-R), decreased adiponectin receptor 1 (Adipo-R1) and 2 (Adipo-R2), and increased Ki-67 levels in small intestine and colon at both time points. Immunoblot analysis further showed increased IGF1R and Ob-R, and decreased Adipo-R2. Additionally, upregulation of PI3K/Akt and JAK2 signaling, which are downstream of IGF1 and leptin, was also observed in irradiated samples at both time points. These results when considered along with increased cell proliferation in the small intestine and colon demonstrate for the first time that ionizing radiation can persistently increase IGF1 and leptin and activate downstream proliferative pathways, which may contribute to GI functional alterations and carcinogenesis.
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Fator de Crescimento Insulin-Like I/metabolismo , Intestinos/efeitos da radiação , Janus Quinase 2/metabolismo , Leptina/metabolismo , Adiponectina/sangue , Animais , Proliferação de Células/efeitos da radiação , Feminino , Raios gama , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Fator de Crescimento Insulin-Like I/genética , Mucosa Intestinal/metabolismo , Leptina/sangue , Leptina/genética , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais , Regulação para CimaRESUMO
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.
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Consumo de Bebidas Alcoólicas/efeitos adversos , Mama/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/genética , Metilação de DNA , Ferredoxina-NADP Redutase/genética , Ácido Fólico/metabolismo , Metilenotetra-Hidrofolato Desidrogenase (NADP)/genética , Adulto , Mama/efeitos dos fármacos , Estudos Transversais , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Feminino , Seguimentos , Humanos , Antígenos de Histocompatibilidade Menor , Prognóstico , Regiões Promotoras Genéticas/genéticaRESUMO
Pancreatic ductal adenocarcinoma (PDAC) is characterized by an extensive fibrotic reaction or desmoplasia and complex involvement of the surrounding tumor microenvironment. Pancreatic stellate cells are a key mediator of the pancreatic matrix and they promote progression and invasion of pancreatic cancer by increasing cell proliferation and offering protection against therapeutic interventions. Our study utilizes human tumor-derived pancreatic stellate cells (HTPSCs) isolated from fine needle aspirates of pancreatic cancer tissue from patients with locally advanced, unresectable pancreatic adenocarcinoma before and after treatment with full-dose gemcitabine plus concurrent hypo-fractionated stereotactic radiosurgery. We show that HTPSCs survive in vivo chemotherapy and radiotherapy treatment and display a more activated phenotype post-therapy. These data support the idea that stellate cells play an essential role in supporting and promoting pancreatic cancer and further research is needed to develop novel treatments targeting the pancreatic tumor microenvironment.
RESUMO
Prostate cancer (PCa) is the most common type of cancer in men in the United States, which disproportionately affects African American descents. While metastasis is the most common cause of death among PCa patients, no specific markers have been assigned to severity and ethnic biasness of the disease. MicroRNAs represent a promising new class of biomarkers owing to their inherent stability and resilience. In the present study, we investigated potential miRNAs that can be used as biomarkers and/or therapeutic targets and can provide insight into the severity and ethnic biasness of PCa. PCR array was performed in FFPE PCa tissues (5 Caucasian American and 5 African American) and selected differentially expressed miRNAs were validated by qRT-PCR, in 40 (15 CA and 25 AA) paired PCa and adjacent normal tissues. Significantly deregulated miRNAs were also analyzed in urine samples to explore their potential as non-invasive biomarker for PCa. Out of 8 miRNAs selected for validation from PCR array data, miR-205 (p<0.0001), mir-214 (p<0.0001), miR-221(p<0.001) and miR-99b (p<0.0001) were significantly downregulated in PCa tissues. ROC curve shows that all four miRNAs successfully discriminated between PCa and adjacent normal tissues. MiR-99b showed significant down regulation (p<0.01) in AA PCa tissues as compared to CA PCa tissues and might be related to the aggressiveness associated with AA population. In urine, miR-205 (p<0.05) and miR-214 (p<0.05) were significantly downregulated in PCa patients and can discriminate PCa patients from healthy individuals with 89% sensitivity and 80% specificity. In conclusion, present study showed that miR-205 and miR-214 are downregulated in PCa and may serve as potential non-invasive molecular biomarker for PCa.
Assuntos
Biomarcadores Tumorais/urina , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica , MicroRNAs/urina , Neoplasias da Próstata/urina , RNA Neoplásico/urina , Negro ou Afro-Americano , Idoso , Perfilação da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/patologia , Sensibilidade e Especificidade , Estados Unidos , População BrancaRESUMO
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.
Assuntos
Anticarcinógenos/uso terapêutico , Genes BRCA1 , Neoplasias Mamárias Experimentais/prevenção & controle , Mutação , PPAR gama/agonistas , Tiazolidinedionas/uso terapêutico , Animais , Diferenciação Celular/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Receptor alfa de Estrogênio/metabolismo , Feminino , Genes p53 , Haploinsuficiência , Neoplasias Mamárias Experimentais/induzido quimicamente , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Invasividade Neoplásica , PPAR gama/metabolismo , Lesões Pré-Cancerosas/prevenção & controle , Proteínas Proto-Oncogênicas c-akt/metabolismo , Tiazolidinedionas/toxicidadeRESUMO
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.
Assuntos
Proteínas de Fusão Oncogênica/metabolismo , Próstata/metabolismo , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/mortalidade , Transativadores/metabolismo , Adulto , Idoso , Estudos de Casos e Controles , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Próstata/patologia , Próstata/cirurgia , Prostatectomia , Neoplasias da Próstata/patologia , Regulador Transcricional ERGRESUMO
Risk of colorectal cancer (CRC) after exposure to low linear energy transfer (low-LET) radiation such as γ-ray is highlighted by the studies in atom bomb survivors. On the contrary, CRC risk prediction after exposure to high-LET cosmic heavy ion radiation exposure is hindered due to scarcity of in vivo data. Therefore, intestinal tumor frequency, size, cluster, and grade were studied in APC(Min/+) mice (n = 20 per group; 6 to 8 wks old; female) 100 to 110 days after exposure to 1.6 or 4 Gy of heavy ion (56)Fe radiation (energy: 1000 MeV/nucleon) and results were compared to γ radiation doses of 2 or 5 Gy, which are equitoxic to 1.6 and 4 Gy (56)Fe respectively. Due to relevance of lower doses to radiotherapy treatment fractions and space exploration, we followed 2 Gy γ and equitoxic 1.6 Gy (56)Fe for comparative analysis of intestinal epithelial cell (IEC) proliferation, differentiation, and ß-catenin signaling pathway alterations between the two radiation types using immunoblot, and immunohistochemistry. Relative to controls and γ-ray, intestinal tumor frequency and grade was significantly higher after (56)Fe radiation. Additionally, tumor incidence per unit of radiation (per cGy) was also higher after (56)Fe radiation relative to γ radiation. Staining for phospho-histone H3, indicative of IEC proliferation, was more and alcian blue staining, indicative of IEC differentiation, was less in (56)Fe than γ irradiated samples. Activation of ß-catenin was more in (56)Fe-irradiated tumor-free and tumor-bearing areas of the intestinal tissues. When considered along with higher levels of cyclin D1, we infer that relative to γ radiation exposure to (56)Fe radiation induced markedly reduced differentiation, and increased proliferative index in IEC resulting in increased intestinal tumors of larger size and grade due to preferentially greater activation of ß-catenin and its downstream effectors.