title: Densely ionizing radiation acts via the microenvironment to promote aggressive Trp53-null mammary carcinomas.
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.
authors.affiliation: Department of Radiation Oncology, New York University School of Medicine, New York, New York.
authors.forename: Irineu
authors.initials: I
authors.lastname: Illa-Bochaca
authors.affiliation: Department of Radiation Oncology, New York University School of Medicine, New York, New York.
authors.forename: Haoxu
authors.initials: H
authors.lastname: Ouyang
authors.affiliation: Department of Pathology, New York University School of Medicine, New York, New York.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Tang
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California.
authors.forename: Christopher
authors.initials: C
authors.lastname: Sebastiano
authors.affiliation: Department of Pathology, New York University School of Medicine, New York, New York.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Mao
authors.affiliation: Department of Pathology, New York University School of Medicine, New York, New York.
authors.forename: Sylvain V
authors.initials: SV
authors.lastname: Costes
authors.affiliation: Department of Radiation Oncology, New York University School of Medicine, New York, New York. Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California.
authors.forename: Sandra
authors.initials: S
authors.lastname: Demaria
authors.affiliation: Department of Radiation Oncology, New York University School of Medicine, New York, New York. mhbarcellos-hoff@nyumc.org.
authors.forename: Mary Helen
authors.initials: MH
authors.lastname: Barcellos-Hoff
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000235:genetics; D015820:Cadherins / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D007633:Keratins / Q000235:genetics; D008325:Mammary Neoplasms, Experimental / Q000235:genetics* / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics; D011839:Radiation, Ionizing; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics; D011960:Receptors, Estrogen / Q000235:genetics; D051880:Receptors, Notch / Q000235:genetics; D013234:Stem Cells / Q000473:pathology; D059016:Tumor Microenvironment / Q000235:genetics*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; D007633:Keratins; D016283:Proto-Oncogene Proteins p21(ras); D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D051880:Receptors, Notch; D016159:Tumor Suppressor Protein p53; C524056:Erbb2 protein, mouse; C495971:Hras protein, mouse