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M94B0785.TXT
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1994-11-11
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Document 0785
DOCN M94B0785
TI H-2K(b) gene and retrovirus interactions in the regulation of BL6
melanoma cell sensitivity to tumor necrosis factor-alpha.
DT 9412
AU Kim M; Univ. of Pittsburgh
SO Diss Abstr Int [B]; 54(6):2980 1993. Unique Identifier : AIDSLINE
ICDB/94605777
AB The effect of major histocompatibility complex (MHC) class I gene
expression on the sensitivity of BL6 melanoma cells to the cytotoxic
effects of TNF-alpha was studied. Experiments were performed using
B16F10BL6 melanoma line (hereafter referred as BL6) that is a highly
invasive and metastatic cell line. BL6 melanoma cells lack of MHC class
I antigens and manifest high resistance to natural cell-mediated
cytotoxicity and TNF-alpha lysis. Clones BL6-8 melanoma (H-2K(b-),
H-2D(b+)) and BL6-2 (H-2K(b-), H-2D(b-)) were transfected with class I
H-2K(b), H-2K(d), H-2D(d), class II H-2IA(k) or neo(r) genes. In
parallel clones of BL6 melanoma expressing the endogenous H-2K(b) and
H-2D(b) genes spontaneously or after treatment with
N-methyl-N-nitro-nitrosoguanidine (MNNG) were isolated. All clones
expressing the endogenous or transfected H-2K(b) but not H-2D(b) gene
showed increased sensitivity to TNF that was further substantially
potentiated by cycloheximide and actinomycin D. Similarly, transfection
of BL6-8 and BL6-2 clones with allelic H-2K(d) increase tumor cell
sensitivity to TNF lysis, whereas class I H-2D(b), H-2D(d), class II
H-2IA(k), and/or neo(r) gene did not reverse resistance of these clones
to TNF lysis. It is unlikely that TNF recognize H-2K molecules and our
data indicate that H-2K molecules are not directly required for or
involved in TNF-induced melanoma cell lysis. The observed increase in
TNF sensitivity and pleiotropic phenotypic changes induced by H-2K gene
had absolute correlation with loss of this retrovirus. Southern blot
analysis using probe specific for env gene of ecotropic retrovirus
revealed that loss of ecotropic retrovirus production in
H-2K(b)-positive BL6 melanoma clones is a result of rearrangements in
the proviral DNA. Study of the mechanisms responsible for TNF
resistance/sensitivity of BL6 melanoma cells showed that H-2K(b) gene
transfection resulted in an increase in p55 TNF receptor expression, and
in augmentation of internalization and degradation of TNF. TNF was
capable of induction of the second intracellular signal, with activation
of MnSOD gene expression and phospholipase A2 activity, only in
H-2K(b)-positive, but not in the parental BL6-8 melanoma cells or cells
transfected with H-2D(d), neo(r), or class II H-2IA(k) genes. Our data
indicate that TNF resistance of BL6 melanoma cells appeared to be due to
a block in transduction of the lytic signal, TNF resistance was reversed
after transfection with H-2K gene and was closely associated with H-2K
gene induced elimination of melanoma-specific ecotropic retrovirus
production. (Abstract shortened by UMI.) (Full text available from
University Microfilms International, Ann Arbor, MI, as Order No.
AAD93-29470)
DE Blotting, Southern DNA, Viral/GENETICS Gene Rearrangement *Genes, MHC
Class I Genes, env Melanoma/*PATHOLOGY Neoplasm Invasiveness
Neoplasm Metastasis Phospholipases A/METABOLISM Proviruses/GENETICS
Retroviridae/*GENETICS Signal Transduction Superoxide
Dismutase/METABOLISM Tumor Cells, Cultured Tumor Necrosis
Factor/*PHYSIOLOGY THESIS
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).