Biomedical subjects

W June Brickey

Publications and source records attributed to W June Brickey.

8 recordsLinked to original sources

PubMed2006

Global functional analysis of nucleophosmin in Taxol response, cancer, chromatin regulation, and ribosomal DNA transcription.

Analysis of lung cancer response to chemotherapeutic agents showed the accumulation of a Taxol-induced protein that reacted with an anti-phospho-MEK1/2 antibody. Mass spectroscopy identified the protein as nucleophosmin/B23 (NPM), a multifunctional protein with diverse roles: ribosome biosynthesis, p53 regulation, nuclear-cytoplasmic shuttling, and centrosome duplication. Our work demonstrates that following cellular exposure to mitosis-arresting agents, NPM is phosphorylated and its chromatographic property is altered, suggesting changes in function during mitosis. To determine the functional relevance of NPM, its expression in tumor cells was reduced by siRNA. Cells with reduced NPM were treated with Taxol followed by microarray profiling accompanied by gene/protein pathway analyses. These studies demonstrate several expected and unexpected consequences of NPM depletion. The predominant downstream effectors of NPM are genes involved in cell proliferation, cancer, and the cell cycle. In congruence with its role in cancer, NPM is over-expressed in primary malignant lung cancer tissues. We also demonstrate a role for NPM in the expression of genes encoding SET (TAF1beta) and the histone methylase SET8. Additionally, we show that NPM is required for a previously unobserved G2/M upregulation of TAF1A, which encodes the rDNA transcription factor TAF(I)48. These results demonstrate multi-faceted functions of NPM that can affect cancer cells.

Antineoplastic Agents, Phytogenic↗

PubMed2005

C-C chemokine receptor 5 on stromal cells promotes pulmonary metastasis.

We have shown that mice that express the C-C chemokine receptor 5 (CCR5) have enhanced local tumor growth and an impaired response to vaccine therapy compared with CCR5 knockout (CCR5(-/-)) mice. Here, we extend these observations to evaluate the function of CCR5 in pulmonary metastasis and the mechanism underlying the diminished tumor growth in CCR5(-/-) mice. Lung metastases were counted in wild-type (WT) and CCR5(-/-) mice following the injection of 1 x 10(6) B16-F10 melanoma cells. These results were compared with those from syngeneic bone marrow chimeric mice formed by the transfer of WT bone marrow into irradiated CCR5(-/-) and CCR5(-/-) marrow into irradiated WT mice. Intact CCR5(-/-) mice developed fewer metastases than WT mice (40.2 versus 70.6; P < 0.05). Bone marrow chimeras formed by the transfer of WT bone marrow into CCR5(-/-) hosts had fewer metastases than WT hosts injected with knockout marrow (46.6 versus 98.6; P < 0.01). Adoptive transfer of CCR5-expressing leukocytes also failed to promote metastasis in CCR5(-/-) mice. However, the i.v. transfer of WT pulmonary stromal cells into CCR5(-/-) mice increased the number of metastases compared with transfer of CCR5(-/-) stromal cells (102.8 versus 26.0; P < 0.05). These results show for the first time that CCR5 expression on stromal and not hematopoietic cells contributes to tumor metastasis. Therefore, recently developed CCR5 inhibitors may have a novel benefit in cancer therapy.

Animals↗

PubMed2004

PX3.102, a novel chinese herb extract, diminishes chronic airway allograft rejection.

More effective immunosuppressants are needed to improve lung-transplantation survival. PX3.102 is a novel immunosuppressant isolated from a mixture of traditional Chinese herbs. We tested its protective role on chronic lung rejection in the heterotopic tracheal transplant model. C57BL/6 mice received BALB/c tracheal grafts and were treated with PX3.102, cyclosporine A, or vehicle. PX3.102 improved tracheal allograft lumen patency (*P<0.01 vs. vehicle and P=0.14 vs. cyclosporine A) but not epithelialization (P>0.2 vs. vehicle). Subsequent in vitro studies demonstrated that PX3.10 was toxic to fully differentiated human tracheal epithelial cells in a dose-dependent manner. PX3.102 markedly suppressed antigen-specific lymphocyte proliferation in vitro at a concentration 10 times lower than cyclosporine A. In conclusion, PX3.102, a promising and potent immunosuppressant, although exhibiting toxicity to airway epithelial cells at high doses, is effective in inhibiting chronic airway allograft rejection.

Animals↗

PubMed2003

CIITA-regulated plexin-A1 affects T-cell-dendritic cell interactions.

The major histocompatibility complex (MHC) class II transactivator (CIITA) is the 'master coactivator' of MHC class II genes. To identify new targets of CIITA, we analyzed cDNA microarrays of dendritic cells (DCs) from CIITA-deficient, MHC class II-deficient and control mice. We found the semaphorin receptor plexin-A1 was expressed in DCs, but not in other immune cells, and was strongly induced by CIITA. RNA interference by short hairpin RNA specific for plexin-A1, but not a single-nucleotide mutant, greatly reduced plexin-A1 expression and T cell stimulation by protein- or peptide-antigen-pulsed DCs.Plexin-A1 is not required for peptide binding to MHC. These data indicate involvement of plexin-A1 in T cell-DC interactions but not antigen processing or binding.

Animals↗

PubMed2002

The role of the MHC class II transactivator in class II expression and antigen presentation by astrocytes and in susceptibility to central nervous system autoimmune disease.

The role of the MHC class II transactivator (CIITA) in Ag presentation by astrocytes and susceptibility to experimental autoimmune encephalomyelitis (EAE) was examined using CIITA-deficient mice and newly created transgenic mice that used the glial fibrillary acidic protein promoter to target CIITA expression in astrocytes. CIITA was required for class II expression on astrocytes. Like class II-deficient mice, CIITA-deficient mice were resistant to EAE by immunization with CNS autoantigen, although T cells from immunized CIITA-deficient, but not class II-deficient, mice proliferated and secreted Th1 cytokines. CIITA-deficient splenic APC presented encephalitogenic peptide to purified wild-type encephalitogenic CD4(+) T cells, indicating that CIITA-independent mechanisms can be used for class II-restricted Ag presentation in lymphoid tissue. CIITA-deficient mice were also resistant to EAE by adoptive transfer of encephalitogenic class II-restricted CD4(+) Th1 cells, indicating that CIITA-dependent class II expression was required for CNS Ag presentation. Despite constitutive CIITA-driven class II expression on astrocytes in vivo, glial fibrillary acidic protein-CIITA transgenic mice were no more susceptible to EAE than controls. CIITA-transfected astrocytes presented peptide Ag, but in contrast to IFN-gamma-activated astrocytes, they could not process and present native Ag. CIITA-transfected astrocytes did not express cathepsin S without IFN-gamma activation, indicating that CIITA does not regulate other elements that may be required for Ag processing by astrocytes. Although our results demonstrate that CIITA-directed class II expression is required for EAE induction, CIITA-directed class II expression by astrocytes does not appear to increase EAE susceptibility. These results do not support the role of astrocytes as APC for class II-restricted Ag presentation during the induction phase of EAE.

Amino Acid Sequence↗

PubMed2002

Hierarchical contributions of allorecognition pathways in chronic lung rejection.

The role of allorecognition in initiating lung graft rejection is not clearly defined. Using the heterotopic tracheal transplantation model, we examined the contributions of the indirect and direct allorecognition pathways in chronic airway rejection. Fully mismatched, wild-type grafts were transplanted into major histocompatibility complex (MHC) II-/-, class II-like accessory molecule (H2-DMalpha)-/- using MHC I-/- and wild-type allorecipients as control subjects. Similarly, MHC I-/-, MHC II-/-, or MHC I/II-/- allografts were transplanted into wild-type mice with appropriate control subjects. Grafts from nonimmunosuppressed recipients were evaluated at Weeks 2, 4, and 6. Grafts transplanted into MHC II-/- and H2-DMalpha-/- allorecipients showed a more intact epithelium and reduced lumen obliteration compared with grafts transplanted into wild-type or MHC I-/- allorecipients (p < 0.05 for each). These grafts exhibited abundant CD4+ and CD8+ cell infiltrates similar to control allografts. MHC I-/- and MHC I/II-/- but not MHC II-/- allografts placed in wild-type animals demonstrated less severe rejection compared with allograft control subjects (p < 0.05 for each). Although the indirect allorecognition pathway has the strongest influence on rejection, the direct pathway is sufficient to ultimately cause chronic airway rejection. In addition, these results suggest that MHC class I molecules are the principal alloantigens in the mouse heterotopic tracheal model of obliterative bronchiolitis.

Animals↗

PubMed2002

Prolonged survival of class II transactivator-deficient cardiac allografts.

BACKGROUND: Major histocompatibility complex (MHC) antigenic complexes trigger allogeneic T-cell responses and allograft rejection. MHC class II and related antigen processing genes, such as invariant chain (Ii) and H2-DM accessory molecules, are controlled by the master transcriptional regulator, class II transactivator (CIITA). CIITA also up-regulates MHC class I gene expression in vitro. Thus, disruption of a single factor, namely CIITA, represents an ideal strategy for reducing transplant rejection. METHODS: We studied the immunological advantages of transplanting CIITA deficient hearts into mismatched recipients in comparison to wild-type (B6) allografts or MHC class II-deficient (Abeta ) hearts. RESULTS: Elimination of CIITA greatly enhanced graft survival (median survival time [MST] 36 days) over the survival of wild-type (MST 9 days) and even over Abeta (MST 20 days) cardiac grafts. This was accompanied by greatly reduced mixed lymphocyte reactivity and in vivo antigen priming capacity. Analyses for CD4, CD8, and other inflammatory cells, plus cytotoxic T-cell activity and MHC class I specific alloantibody production, did not reveal significant differences in CIITA allograft tissues. Some cytokines that may support immunosuppression, such as transforming growth factor (TGF)-beta, were increased in mice receiving either Abeta or CIITA cardiac grafts. CONCLUSIONS: We conclude that disruption of CIITA function plays a beneficial role in preventing normal allogeneic T-cell responses. Even though inflammatory cells are present in CIITA allografts, the dramatic prolongation in allograft survival of CIITA hearts as compared with wild-type grafts provides a foundation for designing molecular therapies to interfere with MHC class II function and thereby reduce transplantation rejection.

Animals↗

PubMed2002

Transfection of macrophage inflammatory protein 1 alpha into B16 F10 melanoma cells inhibits growth of pulmonary metastases but not subcutaneous tumors.

Macrophage inflammatory protein 1 alpha (MIP-1 alpha), a CC chemokine, is a chemoattractant for T cells and immature dendritic cells. Plasmacytoma cells expressing MIP-1 alpha generate a cytotoxic T cell response without affecting tumor growth. To understand this discrepancy, we compared a local tumor model with a metastatic one using MIP-1 alpha-transfected B16 F10 melanoma cells. Clonal idiosyncrasies were controlled by selecting three lipotransfected tumor clones and two pcDNA vector transfected control clones with equivalent in vitro proliferative capacities. No significant differences were seen between the MIP-1 alpha-producing and control melanoma cells after s.c. injection in the hind leg. All animals had a leg diameter of 10 cm in 18.5-21.5 days. However, after i.v. injection the number of pulmonary foci was significantly reduced in the MIP-1 alpha-producing clones. Injection of 10(6) control transfected cells resulted in a median of 98.5 tumor foci in 2 wk, whereas the injection of the MIP-1 alpha-producing clones resulted in 89.5, 26.5, and 0 foci. The number of metastatic foci was inversely proportional to the amount of MIP-1 alpha produced by the clone in vitro. Flow cytometry showed a significant increase in CD8(+) cells in lungs of mice with MIP-1 alpha-transfected tumors 3 days after injection. This increase was not maintained 10 days later despite continued production of MIP-1 alpha. The protection offered by transfection with MIP-1 alpha was significantly impaired in beta(2)-microglobulin(-/-) mice. Our findings suggest that MIP-1 alpha is effective in preventing the initiation of metastasis, but not at sustaining an effective antitumor response.

Animals↗