| Immunol Invest. 1997 Apr;26(3):351-70. |
|
An RGD containing
peptide from HIV-1 Tat-(65-80) modulates protooncogene
expression in human bronchoalveolar carcinoma cell
line, A549.
el-Solh A, Kumar
NM, Nair MP, Schwartz SA, Lwebuga-Mukasa JS.
Department of Internal Medicine, SUNY
at Buffalo School of Medicine and Biomedical Sciences, Buffalo General Hospital 14203,
Tat (transactivator of transcription) is essential
for HIV-1 replication in vivo and in vitro. Tat-(65-80), an RGD
containing domain, has been shown to regulate proliferative
function of a variety of cell lines, including a human adenocarcinoma
cell line, A549. The exact cellular and molecular mechanisms
by which these effects are mediated, remain unknown. To evaluate the hypothesis
that Tat-(65-80) modulates the expression of immediate early genes (IEG) c-jun, c-myc,
c-fos and the tumor suppressor gene p53, serum starved
A549 cells were incubated with Tat-(65-80) or heat-inactivated Tat-(65-80)
at 10 ng/ml. Total cellular RNA was isolated from
the cells at various time points (0-24 hours). In each case, 5 micrograms
of RNA was reverse transcribed in 20 microliters
of reaction volume. Equal amounts of cDNA were subjected
to polymerase chain reaction (PCR) and analyzed
by electrophoresis. The photographic negatives of the ethidium bromide stained gels were quantitated
by densitometric scanning and normalized to corresponding
beta-actin PCR products.
Treatment with Tat-(65-80) showed a twofold induction of c-jun at 0.5 h. Peak expression occurred at 60 minutes and remained
above baseline at 24 hours (h). c-myc was increased
at 0.5 h, reached a twofold increase at 2 h and remained above baseline at
24 h. c-fos increased seven fold at 0.5 h and declined
subsequently to baseline at 8 h. p-53 gene was reduced fivefold at 0.5 h and
remained downregulated thereafter. These results
show that Tat-(65-80) can modulate growth related genes in human lung epithelial
cells.
PMID: 9129988 [PubMed
- indexed for MEDLINE]