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).