Degradation of NF-kappa B in T cells by gangliosides expressed on renal cell carcinomas.
T cells from cancer patients are often functionally impaired, which imposes a barrier to effective immunotherapy. Most pronounced are the alterations characterizing tumor-infiltrating T cells, which in renal cell carcinomas includes defective NF-kappaB activation and a heightened sensitivity to apoptosis. Coculture experiments revealed that renal tumor cell lines induced a time-dependent decrease in RelA(p65) and p50 protein levels within both Jurkat T cells and peripheral blood T lymphocytes that coincided with the onset of apoptosis. The degradation of RelA/p50 is critical for SK-RC-45-induced apoptosis because overexpression of RelA in Jurkat cells protects against cell death. The loss of RelA/p50 coincided with a decrease in expression of the NF-kappaB regulated antiapoptotic protein Bcl-xL at both the protein and mRNA level. The disappearance of RelA/p50 protein was mediated by a caspase-dependent pathway because pretreatment of T lymphocytes with a pan caspase inhibitor before coculture with SK-RC-45 blocked RelA and p50 degradation. SK-RC-45 gangliosides appear to mediate this degradative pathway, as blocking ganglioside synthesis in SK-RC-45 cells with the glucosylceramide synthase inhibitor, PPPP, protected T cells from tumor cell-induced RelA degradation and apoptosis. The ability of the Bcl-2 transgene to protect Jurkat cells from RelA degradation, caspase activation, and apoptosis implicates the mitochondria in these SK-RC-45 ganglioside-mediated effects.
Thornton
Mark V
MV
Department of Immunology, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
Kudo
Daisuke
D
Rayman
Patricia
P
Horton
Claudine
C
Molto
Luis
L
Cathcart
Martha K
MK
Ng
Christopher
C
Paszkiewicz-Kozik
Ewa
E
Bukowski
Ronald
R
Derweesh
Ithaar
I
Tannenbaum
Charles S
CS
Finke
James H
JH
D000276:Adjuvants, Immunologic / Q000096:biosynthesis / Q000502:physiology; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D002292:Carcinoma, Renal Cell / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D020169:Caspases / Q000502:physiology; D002460:Cell Line; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D005732:Gangliosides / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000502:physiology*; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors; D006131:Growth Inhibitors / Q000096:biosynthesis / Q000502:physiology; D006801:Humans; D019169:Jurkat Cells; D007680:Kidney Neoplasms / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism* / Q000502:physiology; D052002:NF-kappa B p50 Subunit; D011412:Propanolamines / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D016176:T-Lymphocyte Subsets / Q000378:metabolism*; D051996:Transcription Factor RelA
C110417:1-phenyl-2-hexadecanoylamino-3-pyrrolidino-1-propanol; D000276:Adjuvants, Immunologic; D005732:Gangliosides; D006131:Growth Inhibitors; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D011412:Propanolamines; D011759:Pyrrolidines; D051996:Transcription Factor RelA; D005964:Glucosyltransferases; C023246:ceramide glucosyltransferase; D020169:Caspases