Fascin-1 knock-down of human glioma cells reduces their microvilli/filopodia while improving their susceptibility to lymphocyte-mediated cytotoxicity

Cancer cells derived from Glioblastoma multiforme possess membranous protrusions allowing these cells to infiltrate surrounding tissue, while resisting lymphocyte cytotoxicity. Microvilli and filopodia are supported by actin filaments cross-linked by fascin. Fascin-1 was genetically silenced within human U251 glioma cells; these knock-down glioma cells lost their microvilli/filopodia. The doubling time of these fascin-1 knock-down cells was doubled that of shRNA control U251 cells. Fascin-1 knock-down cells lost their transmigratory ability responding to interleukin-6 or insulin-like growth factor-1. Fascin-1 silenced U251 cells were more easily killed by cytolytic lymphocytes. Fascin-1 knock-down provides unique opportunities to augment glioma immunotherapy by simultaneously targeting several key glioma functions: like cell transmigration, cell division and resisting immune responses.

Gliomas display complex cell surface topographies that resist cytolytic lymphocytes but are reversed by using fascin siRNA (48.2)

Gliomas are invasive cancers that resist all forms of attempted therapy, but immunotherapy has improved survival for some patients. We present evidence that another level of complexity may also contribute to lack of responses by the lymphocytes towards gliomas. Atomic force microscopy of four different glioma types: human U251 and rat T9 and F98 glioma cells, including freshly isolated human GBM neurosphere cultures (containing “stem cell-like cells’), revealed a complex surface topography with numerous microvilli and filopodia. These structures were not found on other cell types. Electron microscopy and immunofluorescence microscopy of glioma cells confirmed that microvilli are present. U251 cells with microvilli resisted the cytolytic actions of different human effector cells, (lymphokine-activated killer cells, γδ T cells, conventional cytolytic T lymphocytes, [CTL], and chimeric antigen receptor redirected T cells) better than their non-microvilli expressing counterparts. Killer cells released perforin which was detected within the glioma’s microvilli/ filopodia, indicating these structures can receive the cytolytic effector molecules, but cytotoxicity is suboptimal. Transfection of fascin siRNA into U251 cells prevented the microvilli from forming and allowed cytolytic cells to kill these adherent cells just as well as the non-attached glioma cells. These microvilli play multiple roles in glioma biology, such as invasion and resistance to lymphocyte-mediated killing.

Mutation in the glycosylated gag protein of murine leukemia virus results in reduced in vivo infectivity and a novel defect in viral budding or release

All gammaretroviruses, including murine leukemia viruses (MuLVs), feline leukemia viruses, and gibbon-ape leukemia virus, encode an alternate, glycosylated form of Gag polyprotein (glyco-Gag or gPr80gag) in addition to the polyprotein precursor of the viral capsid proteins (Pr65gag). gPr80gag is translated from an upstream in-frame CUG initiation codon, in contrast to the AUG codon used for Pr65gag. The role of glyco-Gag in MuLV replication has been unclear, since gPr80gag-negative Moloney MuLV (M-MuLV) mutants are replication competent in vitro and pathogenic in vivo. However, reversion to the wild type is frequently observed in vivo. In these experiments, in vivo inoculation of a gPr80gag mutant, Ab-X-M-MuLV, showed substantially lower (2 log) initial infectivity in newborn NIH Swiss mice than that of wild-type virus, and revertants to the wild type could be detected by PCR cloning and DNA sequencing as early as 15 days postinfection. Atomic force microscopy of Ab-X-M-MuLV-infected producer cells or of the PA317 amphotropic MuLV-based vector packaging line (also gPr80gag negative) revealed the presence of tube-like viral structures on the cell surface. In contrast, wild-type virus-infected cells showed the typical spherical, 145-nm particles observed previously. Expression of gPr80gag in PA317 cells converted the tube-like structures to typical spherical particles. PA317 cells expressing gPr80gag produced 5- to 10-fold more infectious vector or viral particles as well. Metabolic labeling studies indicated that this reflected enhanced virus particle release rather than increased viral protein synthesis. These results indicate that gPr80gag is important for M-MuLV replication in vivo and in vitro and that the protein may be involved in a late step in viral budding or release.

Air quality modeling for Houston-Galveston-Brazoria area

A coupled numerical model of the atmospheric thermo-hydrodynamics and pollutant photochemical transport is described. This model can be used to study the complex relationships between the chemical and thermo-hydrodynamic processes in the atmosphere of urban areas with an emphasis on photochemical ozone formation. Preliminary numerical results of ozone and other key chemical atmospheric pollutant concentrations and distribution across the Houston-Galveston-Brazoria area using virtual emission data from area and mobile sources are presented.

Parity violation in proton-proton scattering at 221 MeV

The parity-violating longitudinal analyzing power, A(z), has been measured in pvectorp elastic scattering at an incident proton energy of 221 MeV. The result obtained is A(z) = [0.84+/-0.29(stat)+/-0.17(syst)]x10(-7). This experiment is unique in that it selects a single parity violating transition amplitude (3P2 - 1D2) and consequently directly constrains the weak meson-nucleon coupling constant h(pp)(rho). When this result is taken together with the existing pvectorp parity violation data, the weak meson-nucleon coupling constants h(pp)(rho) and h(pp)(omega) can, for the first time, both be determined.