Breast cancer cell lines carry cell line-specific genomic alterations that are distinct from aberrations in breast cancer tissues: Comparison of the CGH profiles between cancer cell lines and primary cancer tissues

<p>Abstract</p> <p>Background</p> <p>Cell lines are commonly used in various kinds of biomedical research in the world. However, it remains uncertain whether genomic alterations existing in primary tumor tissues are represented in cell lines and whether cell lines carry cell line-specific genomic alterations. This study was performed to answer these questions.</p> <p>Methods</p> <p>Array-based comparative genomic hybridization (CGH) was employed with 4030 bacterial artificial chromosomes (BACs) that cover the genome at 1.0 megabase resolution to analyze DNA copy number aberrations (DCNAs) in 35 primary breast tumors and 24 breast cancer cell lines. DCNAs were compared between these two groups. A tissue microdissection technique was applied to primary tumor tissues to reduce the contamination of samples by normal tissue components.</p> <p>Results</p> <p>The average number of BAC clones with DCNAs was 1832 (45.3% of spotted clones) and 971 (24.9%) for cell lines and primary tumor tissues, respectively. Gains of 1q and 8q and losses of 8p, 11q, 16q and 17p were detected in >50% of primary cancer tissues. These aberrations were also frequently detected in cell lines. In addition to these alterations, the cell lines showed recurrent genomic alterations including gains of 5p14-15, 20q11 and 20q13 and losses of 4p13-p16, 18q12, 18q21, Xq21.1 and Xq26-q28 that were barely detected in tumor tissue specimens. These are considered to be cell line-specific DCNAs. The frequency of the HER2 amplification was high in both cell lines and tumor tissues, but it was statistically different between cell lines and primary tumors (P = 0.012); 41.3 ± 29.9% for the cell lines and 15.9 ± 18.6% for the tissue specimens.</p> <p>Conclusions</p> <p>Established cell lines carry cell lines-specific DCNAs together with recurrent aberrations detected in primary tumor tissues. It must therefore be emphasized that cell lines do not always represent the genotypes of parental tumor tissues.</p

Dynamical transport of photoexcited carriers between shallow and deep quantum wells embedded in a GaAs/AlAs superlattice

Temperature dependence of the emission properties in a novel compositequantum-well-structure consisting of wide and narrow GaAs quantum wells (QWs) embeddedin a GaAs/AlAs short-period superlattice (SPS) has been studied by steady-state andtime-resolved photoluminescence (PL) measurements. At low temperature (~20 K), distinctPL peaks originating from the QWs and SPS are observed. When temperature is increased to60 K, the PL intensity of the wide QW with deep confinement states significantly increases,while the ones of the narrow QW and the SPS gradually decrease. Above 100 K, however, theformer PL intensity decreases and the latter ones increase. Temperature dependence of themeasured PL decay behaviors directly evidences that the complex PL properties of thecomposite QWs are due to the interplay of the photoexcited carriers between the deep andshallow QWs by Bloch-type transport in the SPS

In vivo 3D analysis of systemic effects after local heavy-ion beam irradiation in an animal model

Radiotherapy is widely used in cancer treatment. In addition to inducing effects in the irradiated area, irradiation may induce effects on tissues close to and distant from the irradiated area. Japanese medaka, Oryzias latipes, is a small teleost fish and a model organism for evaluating the environmental effects of radiation. In this study, we applied low-energy carbon-ion (26.7 MeV/u) irradiation to adult medaka to a depth of approximately 2.2 mm from the body surface using an irradiation system at the National Institutes for Quantum and Radiological Science and Technology. We histologically evaluated the systemic alterations induced by irradiation using serial sections of the whole body, and conducted a heart rate analysis. Tissues from the irradiated side showed signs of serious injury that corresponded with the radiation dose. A 3D reconstruction analysis of the kidney sections showed reductions in the kidney volume and blood cell mass along the irradiated area, reflecting the precise localization of the injuries caused by carbon-beam irradiation. Capillary aneurysms were observed in the gill in both ventrally and dorsally irradiated fish, suggesting systemic irradiation effects. The present study provides an in vivo model for further investigation of the effects of irradiation beyond the locally irradiated area