The recent discovery that fullerenes (C60) can be produced in macroscopic quantities has sparked much interest in the chemistry of this unusual molecule. Concerns have also arose about the potential carcinogenic effects of this molecule. We have addressed the potential acute and subchronic toxic effects of fullerenes applied in benzene on the mouse skin. The acute toxic effects measured in this study included epidermal DNA synthesis and the induction of ornithine decarboxylase activity in the epidermis. At the topical dose of fullerenes used in these studies (i.e., 200 ug), we found no effect on either DNA synthesis or ornithine decarboxylase activity over a 72 hour time course after treatment. The subchronic effects of the fullerenes as a mouse skin tumor promoter was assessed by repeatedly applying the chemical to the skin after initiation with the polycyclic aromatic hydrocarbon, 7,12-dimethlybenz-anthracene (DMBA). Repeated administration of the fullerenes for up to 24 weeks post-initiation did not result in either benign or malignant skin tumor formation, whereas promotion with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA) resulted in the formation of benign skin tumors. Our data indicate that fullerenes applied in benzene at a likely industrial exposure level do not cause acute toxic effects on the mouse skin epidermis.

Introduction: ECM1 is known to be over-expressed in multiple tumor cell lines and primary tumors, including breast cancers. ECM1 overexpression is also an independent predictor of poor prognosis in primary breast carcinomas. While similar associations have also been reported in other tumors, the mechanisms by which ECM1 affects prognosis have not been elucidated. Methods: ECM1 was silenced in the Hs578t and MDA-MB231 breast cancer cell lines using siRNA. The cells were evaluated for morphological changes, migration (wound-healing assay, TScratch program), matrigel invasion and cell attachment. Real Time RT-PCR using a 94-geneTumor Metastasis Array (TaqMan), was performed to assess the effects of ECM1 downregulation on in Hs578t cells. Alterations in RNA expression were validated at the protein level using western blots. Differences between groups were evaluated using the student's t-test and p<0.05 was considered statistically significant. Results: ECM1 silenced cells demonstrated altered morphology with a more elongated appearance to the cells, when compared those transfected with non-targeting siRNA. Reduced cell migration was noted for both silenced Hs578t and MB231 cell lines (both p<0.0001). Matrigel invasion was reduced in the Hs578t cell line only (p<0.002). however, cell attachment was decreased in both cell lines. (p <0.0001 for Hs578t, and < 0.01 for MB231). ECM1 downregulation affected the expression of several metastasis associated genes including CD44, Metalloproteinase-2, fibronectin at the RNA level. CD44 expression was significantly reduced in ECM1-silenced cells by western blot. Conclusion: ECM1 appears to be involved in maintenance of tumor cell shape, migration, invasion and attachment properties in the cell lines tested, and also affects expression of CD44 protein, a known tumor prognostic factor. ECM1 may be a key molecule affecting tumor progression and metastasis, which is a complex process involving these components. Our findings suggest mechanisms by which ECM1 overexpression may affect tumor prognosis. Further work is needed to evaluate if altering ECM1 expression may be a novel therapeutic option for these tumors. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-04-16.

The annealing of dielectric thin film coatings has been explored in an attempt to identify the potential benefits of this method of post deposition treatment. Single layer coatings fabricated using several different deposition techniques were annealed and subsequently characterized. All properties so determined evidenced substantial changes as a result of the annealing process. Film microstructure, optical absorption levels, and laser damage thresholds varied considerably with annealing power levels. Although oven annealing is known to improve the performance of certain types of multilayer films, significant improvements were seen only in certain films over a limited range of annealing conditions. As a consequence of this, there were changes in other important optical properties, which will be discussed as well.

Mass spectrometry was used to investigate particle emission, specifically contaminant species, as a possible precursor to laser damage. Experiments were carried out in a clean ultra-high vacuum chamber with a background pressure of 4×10-8Pa. Both pulsed (8 ns) and CW Nd:YAG lasers operating at 1.06 microns were used to irradiate a variety of samples which included uncoated Si, fused silica coated with films of Al2O3, MgF2, or ZrO2, and Si coated with a SiO2/ZrO2 stack. In the pulsed laser experiments, both 1-on-1 and N-on-1 irradiations were investigated. Emitted particles were mass analyzed with a quadruple mass spectrometer which recorded the partial pressure of a given species as a function of time. Single pulse damage thresholds found in this study were consistent with those reported in the literature. Important differences are exhibited in pulse radiation data depending upon whether the laser fluence is above or below the damage threshold as well as upon the type of sample irradiated. In CW laser experiments, fluence was sufficient to cause damage only in the SiO2/ZrO2multilayered coating due to absorption by the Si substrate. CW irradiation also resulted in desorption signals at lower fluences than was possible with pulsed radiation.