Cell-surface Tumoricidal Molecules and NF-kB in the Tumor-burdened Host

Tumor-distal immune suppression promotes tumor growth by preventing the recruitment of leukocytes to the tumor-proximal microenvironment. Tumor necrosis factor (TNF)-a is both secreted by and expressed on the cell-surface (mTNF-a) of macrophages. When stimulated with LPS, tumor-burdened host (TBH) macrophages secrete more TNF-a than normal host (NH) macrophages. In this study, I showed that mTNF-a is elevated both in freshly isolated and stimulated TBH macrophages. Additionally, I analyzed the expression of Fas and FasL on freshly isolated and LPS-stimulated macrophages and found no differences between TBH and NH macrophages. Fas and Fas ligand (FasL) cell-surface expression was analyzed on NH and TBH T-cells. While no difference was observed in freshly isolated cells, cell-surface expression of both proteins remained higher in TBH T-cells than NH T-cells after mitogenic stimulation. Fas and FasL analysis was also extended to the MethKDE fibrosarcoma and I found that these tumor cells express high levels of FasL. Because past observations show increased TNF-a mRNA expression in TBH macrophages relative to NH macrophages, I hypothesized that NF-kB activation may be increased as well. NF-kB is a transcription factor whose activation is required for TNF-a transcription. I observed increased NF-kB activation in both splenic and peritoneal TBH macrophages. Interestingly, electrophoretic mobility shift analysis (EMSA) suggests that different species of NF-kB were found in each distinct population of macrophages. Together, these data demonstrate that cell-surface tumoricidal molecules and NF-kB are dysregulated in the tumor-burdened host.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Biology

Department dc:contributor.department

Biology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2002

Author dc:creator

• McConnell, Michael James

Chair dc:contributor.committeechair

• Elgert, Klaus D.

Committee members dc:contributor.committeemember

• Rutherford, Charles L.
• Winkel, Brenda S. J.

• Fas
• mTNF-a
• MethKDE fibrosarcoma
• NF-kB
• FasL

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-07022002-152228

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/9609