@article {219, title = {Identification of genetic loci that control mammary tumor susceptibility through the host microenvironment.}, journal = {Sci Rep}, volume = {5}, year = {2015}, month = {2015}, pages = {8919}, abstract = {

The interplay between host genetics, tumor microenvironment and environmental exposure in cancer susceptibility remains poorly understood. Here we assessed the genetic control of stromal mediation of mammary tumor susceptibility to low dose ionizing radiation (LDIR) using backcrossed F1 into BALB/c (F1Bx) between cancer susceptible (BALB/c) and resistant (SPRET/EiJ) mouse strains. Tumor formation was evaluated after transplantation of non-irradiated Trp53-/- BALB/c mammary gland fragments into cleared fat pads of F1Bx hosts. Genome-wide linkage analysis revealed 2 genetic loci that constitute the baseline susceptibility via host microenvironment. However, once challenged with LDIR, we discovered 13 additional loci that were enriched for genes involved in cytokines, including TGFβ1 signaling. Surprisingly, LDIR-treated F1Bx cohort significantly reduced incidence of mammary tumors from Trp53-/- fragments as well as prolonged tumor latency, compared to sham-treated controls. We demonstrated further that plasma levels of specific cytokines were significantly correlated with tumor latency. Using an ex vivo 3-D assay, we confirmed TGFβ1 as a strong candidate for reduced mammary invasion in SPRET/EiJ, which could explain resistance of this strain to mammary cancer risk following LDIR. Our results open possible new avenues to understand mechanisms of genes operating via the stroma that affect cancer risk from external environmental exposures.

}, keywords = {Animals, Breast Neoplasms, Cell Line, Tumor, Cytokines, Female, Genetic Predisposition to Disease, Mice, Mice, Inbred BALB C, Neoplasms, Radiation-Induced, Quantitative Trait Loci, Risk Factors, Transforming Growth Factor beta1, Tumor Microenvironment}, issn = {2045-2322}, doi = {10.1038/srep08919}, author = {Zhang, Pengju and Lo, Alvin and Huang, Yurong and Huang, Ge and Liang, Guozhou and Mott, Joni and Karpen, Gary H and Blakely, Eleanor A and Bissell, Mina J and Barcellos-Hoff, Mary Helen and A Snijders and Jiang-Hua Mao} } @article {212, title = {Densely ionizing radiation acts via the microenvironment to promote aggressive Trp53-null mammary carcinomas.}, journal = {Cancer Res}, volume = {74}, year = {2014}, month = {2014 Dec 1}, pages = {7137-48}, abstract = {

Densely ionizing radiation, which is present in the space radiation environment and used in radiation oncology, has potentially greater carcinogenic effect compared with sparsely ionizing radiation that is prevalent on earth. Here, we used a radiation chimera in which mice were exposed to densely ionizing 350 MeV/amu Si-particles, γ-radiation, or sham-irradiated and transplanted 3 days later with syngeneic Trp53-null mammary fragments. Trp53-null tumors arising in mice irradiated with Si-particles had a shorter median time to appearance and grew faster once detected compared with those in sham-irradiated or γ-irradiated mice. Tumors were further classified by markers keratin 8/18 (K18, KRT18), keratin 14 (K14, KRT14) and estrogen receptor (ER, ESR1), and expression profiling. Most tumors arising in sham-irradiated hosts were comprised of both K18- and K14-positive cells (K14/18) while those tumors arising in irradiated hosts were mostly K18. Keratin staining was significantly associated with ER status: K14/18 tumors were predominantly ER-positive, whereas K18 tumors were predominantly ER-negative. Genes differentially expressed in K18 tumors compared with K14/18 tumor were associated with ERBB2 and KRAS, metastasis, and loss of E-cadherin. Consistent with this, K18 tumors tended to grow faster and be more metastatic than K14/18 tumors, however, K18 tumors in particle-irradiated mice grew significantly larger and were more metastatic compared with sham-irradiated mice. An expression profile that distinguished K18 tumors arising in particle-irradiated mice compared with sham-irradiated mice was enriched in mammary stem cell, stroma, and Notch signaling genes. These data suggest that carcinogenic effects of densely ionizing radiation are mediated by the microenvironment, which elicits more aggressive tumors compared with similar tumors arising in sham-irradiated hosts.

}, keywords = {Animals, Biomarkers, Tumor, Cadherins, Female, Gene Expression Profiling, Keratins, Mammary Neoplasms, Experimental, Mice, Mice, Inbred BALB C, Proto-Oncogene Proteins p21(ras), Radiation, Ionizing, Receptor, ErbB-2, Receptors, Estrogen, Receptors, Notch, Stem Cells, Tumor Microenvironment, Tumor Suppressor Protein p53}, issn = {1538-7445}, doi = {10.1158/0008-5472.CAN-14-1212}, author = {Illa-Bochaca, Irineu and Ouyang, Haoxu and Tang, Jonathan and Sebastiano, Christopher and Jiang-Hua Mao and Costes, Sylvain V and Demaria, Sandra and Barcellos-Hoff, Mary Helen} } @article {199, title = {Murine microenvironment metaprofiles associate with human cancer etiology and intrinsic subtypes.}, journal = {Clin Cancer Res}, volume = {19}, year = {2013}, month = {2013 Mar 15}, pages = {1353-62}, abstract = {

PURPOSE: Ionizing radiation is a well-established carcinogen in rodent models and a risk factor associated with human cancer. We developed a mouse model that captures radiation effects on host biology by transplanting unirradiated Trp53-null mammary tissue to sham or irradiated hosts. Gene expression profiles of tumors that arose in irradiated mice are distinct from those that arose in na{\"\i}ve hosts. We asked whether expression metaprofiles could discern radiation-preceded human cancer or be informative in sporadic breast cancers.

EXPERIMENTAL DESIGN: Affymetrix microarray gene expression data from 56 Trp53-null mammary tumors were used to define gene profiles and a centroid that discriminates tumors arising in irradiated hosts. These were applied to publicly available human cancer datasets.

RESULTS: Host irradiation induces a metaprofile consisting of gene modules representing stem cells, cell motility, macrophages, and autophagy. Human orthologs of the host irradiation metaprofile discriminated between radiation-preceded and sporadic human thyroid cancers. An irradiated host centroid was strongly associated with estrogen receptor-negative breast cancer. When applied to sporadic human breast cancers, the irradiated host metaprofile strongly associated with basal-like and claudin-low breast cancer intrinsic subtypes. Comparing host irradiation in the context of TGF-β levels showed that inflammation was robustly associated with claudin-low tumors.

CONCLUSIONS: Detection of radiation-preceded human cancer by the irradiated host metaprofile raises possibilities of assessing human cancer etiology. Moreover, the association of the irradiated host metaprofiles with estrogen receptor-negative status and claudin-low subtype suggests that host processes similar to those induced by radiation underlie sporadic cancers.

}, keywords = {Animals, Breast Neoplasms, Female, Gene Expression Regulation, Neoplastic, Humans, Mammary Neoplasms, Animal, Mice, Radiation, Ionizing, Transcriptome, Tumor Microenvironment, Tumor Suppressor Protein p53}, issn = {1078-0432}, doi = {10.1158/1078-0432.CCR-12-3554}, author = {Nguyen, David H and Fredlund, Erik and Zhao, Wei and Perou, Charles M and Balmain, Allan and Jiang-Hua Mao and Barcellos-Hoff, Mary Helen} } @article {77, title = {NFkB disrupts tissue polarity in 3D by preventing integration of microenvironmental signals}, journal = {Oncotarget}, volume = {4}, year = {2013}, month = {2013 Nov}, pages = {2010-20}, abstract = {

The microenvironment of cells controls their phenotype, and thereby the architecture of the emerging multicellular structure or tissue. We have reported more than a dozen microenvironmental factors whose signaling must be integrated in order to effect an organized, functional tissue morphology. However, the factors that prevent integration of signaling pathways that merge form and function are still largely unknown. We have identified nuclear factor kappa B (NFkB) as a transcriptional regulator that disrupts important microenvironmental cues necessary for tissue organization. We compared the gene expression of organized and disorganized epithelial cells of the HMT-3522 breast cancer progression series: the non-malignant S1 cells that form polarized spheres ({\textquoteright}acini{\textquoteright}), the malignant T4-2 cells that form large tumor-like clusters, and the {\textquoteright}phenotypically reverted{\textquoteright} T4-2 cells that polarize as a result of correction of the microenvironmental signaling. We identified 180 genes that display an increased expression in disorganized compared to polarized structures. Network, GSEA and transcription factor binding site analyses suggested that NFkB is a common activator for the 180 genes. NFkB was found to be activated in disorganized breast cancer cells, and inhibition of microenvironmental signaling via EGFR, beta1 integrin, MMPs, or their downstream signals suppressed its activation. The postulated role of NFkB was experimentally verified: Blocking the NFkB pathway with a specific chemical inhibitor or shRNA induced polarization and inhibited invasion of breast cancer cells in 3D cultures. These results may explain why NFkB holds promise as a target for therapeutic intervention: Its inhibition can reverse the oncogenic signaling involved in breast cancer progression and integrate the essential microenvironmental control of tissue architecture.

}, keywords = {Breast Neoplasms, Cell Line, Tumor, Female, Gene Expression, Humans, Imaging, Three-Dimensional, Microarray Analysis, NF-kappa B, Phenotype, Signal Transduction, Transcriptional Activation, Tumor Microenvironment}, issn = {1949-2553}, doi = {10.18632/oncotarget.1451}, author = {Becker-Weimann, Sabine and Xiong, Gaofeng and Furuta, Saori and Ju Han and Kuhn, Irene and Akavia, Uri-David and Pe{\textquoteright}er, Dana and Bissell, Mina J and Xu, Ren} } @article {78, title = {Genetic differences in transcript responses to low-dose ionizing radiation identify tissue functions associated with breast cancer susceptibility}, journal = {PLoS One}, volume = {7}, year = {2012}, month = {2012}, pages = {e45394}, abstract = {

High dose ionizing radiation (IR) is a well-known risk factor for breast cancer but the health effects after low-dose (LD, \<10 cGy) exposures remain highly uncertain. We explored a systems approach that compared LD-induced chromosome damage and transcriptional responses in strains of mice with genetic differences in their sensitivity to radiation-induced mammary cancer (BALB/c and C57BL/6) for the purpose of identifying mechanisms of mammary cancer susceptibility. Unirradiated mammary and blood tissues of these strains differed significantly in baseline expressions of DNA repair, tumor suppressor, and stress response genes. LD exposures of 7.5 cGy (weekly for 4 weeks) did not induce detectable genomic instability in either strain. However, the mammary glands of the sensitive strain but not the resistant strain showed early transcriptional responses involving: (a) diminished immune response, (b) increased cellular stress, (c) altered TGFβ-signaling, and (d) inappropriate expression of developmental genes. One month after LD exposure, the two strains showed opposing responses in transcriptional signatures linked to proliferation, senescence, and microenvironment functions. We also discovered a pre-exposure expression signature in both blood and mammary tissues that is predictive for poor survival among human cancer patients (p = 0.0001), and a post-LD-exposure signature also predictive for poor patient survival (p\<0.0001). There is concordant direction of expression in the LD-exposed sensitive mouse strain, in biomarkers of human DCIS and in biomarkers of human breast tumors. Our findings support the hypothesis that genetic mechanisms that determine susceptibility to LD radiation induced mammary cancer in mice are similar to the tissue mechanisms that determine poor-survival in breast cancer patients. We observed non-linearity of the LD responses providing molecular evidence against the LNT risk model and obtained new evidence that LD responses are strongly influenced by genotype. Our findings suggest that the biological assumptions concerning the mechanisms by which LD radiation is translated into breast cancer risk should be reexamined and suggest a new strategy to identify genetic features that predispose or protect individuals from LD-induced breast cancer.

}, keywords = {Animals, Breast Neoplasms, Dose-Response Relationship, Radiation, Female, Genetic Predisposition to Disease, Genomic Instability, Humans, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Radiation, Ionizing, RNA, Messenger, Survival Analysis, Transcription, Genetic, Tumor Microenvironment}, issn = {1932-6203}, doi = {10.1371/journal.pone.0045394}, author = {A Snijders and Marchetti, Francesco and Bhatnagar, Sandhya and Duru, Nadire and Ju Han and Hu, Zhi and Jiang-Hua Mao and Gray, Joe W and Wyrobek, Andrew J} } @article {175, title = {Gene transcriptional networks integrate microenvironmental signals in human breast cancer.}, journal = {Integr Biol (Camb)}, volume = {3}, year = {2011}, month = {2011 Apr}, pages = {368-74}, abstract = {

A significant amount of evidence shows that microenvironmental signals generated from extracellular matrix (ECM) molecules, soluble factors, and cell-cell adhesion complexes cooperate at the extra- and intracellular level. This synergetic action of microenvironmental cues is crucial for normal mammary gland development and breast malignancy. To explore how the microenvironmental genes coordinate in human breast cancer at the genome level, we have performed gene co-expression network analysis in three independent microarray datasets and identified two microenvironment networks in human breast cancer tissues. Network I represents crosstalk and cooperation of ECM microenvironment and soluble factors during breast malignancy. The correlated expression of cytokines, chemokines, and cell adhesion proteins in Network II implicates the coordinated action of these molecules in modulating the immune response in breast cancer tissues. These results suggest that microenvironmental cues are integrated with gene transcriptional networks to promote breast cancer development.

}, keywords = {Breast Neoplasms, Cadherins, Cytokines, Extracellular Matrix, Extracellular Matrix Proteins, Female, Gene Expression Profiling, Gene Regulatory Networks, Humans, Integrins, Intercellular Signaling Peptides and Proteins, Mammary Glands, Human, Oligonucleotide Array Sequence Analysis, Receptor, Platelet-Derived Growth Factor beta, Receptors, Cytokine, Transforming Growth Factor beta, Tumor Microenvironment}, issn = {1757-9708}, doi = {10.1039/c0ib00087f}, author = {Xu, Ren and Jiang-Hua Mao} } @article {177, title = {Radiation acts on the microenvironment to affect breast carcinogenesis by distinct mechanisms that decrease cancer latency and affect tumor type.}, journal = {Cancer Cell}, volume = {19}, year = {2011}, month = {2011 May 17}, pages = {640-51}, abstract = {

Tissue microenvironment is an important determinant of carcinogenesis. We demonstrate that ionizing radiation, a known carcinogen, affects cancer frequency and characteristics by acting on the microenvironment. Using a mammary chimera model in which an irradiated host is transplanted with oncogenic Trp53 null epithelium, we show accelerated development of aggressive tumors whose molecular signatures were distinct from tumors arising in nonirradiated hosts. Molecular and genetic approaches show that TGFβ mediated tumor acceleration. Tumor molecular signatures implicated TGFβ, and genetically reducing TGFβ abrogated the effect on latency. Surprisingly, tumors from irradiated hosts were predominantly estrogen receptor negative. This effect was TGFβ independent and linked to mammary stem cell activity. Thus, the irradiated microenvironment affects latency and clinically relevant features of cancer through distinct and unexpected mechanisms.

}, keywords = {Animals, Breast Neoplasms, Cell Transformation, Neoplastic, Dose-Response Relationship, Radiation, Epithelial Cells, Female, Gene Expression Profiling, Gene Expression Regulation, Neoplastic, Gene Regulatory Networks, Mammary Glands, Animal, Mice, Mice, Inbred BALB C, Mice, Knockout, Neoplasms, Radiation-Induced, Radiation Chimera, Reaction Time, Receptors, Estrogen, Time Factors, Transforming Growth Factor beta1, Tumor Burden, Tumor Microenvironment, Tumor Suppressor Protein p53, Whole-Body Irradiation}, issn = {1878-3686}, doi = {10.1016/j.ccr.2011.03.011}, author = {Nguyen, David H and Oketch-Rabah, Hellen A and Illa-Bochaca, Irineu and Geyer, Felipe C and Reis-Filho, Jorge S and Jiang-Hua Mao and Ravani, Shraddha A and Zavadil, Jiri and Borowsky, Alexander D and Jerry, D Joseph and Dunphy, Karen A and Seo, Jae Hong and Haslam, Sandra and Medina, Daniel and Barcellos-Hoff, Mary Helen} }