Secretion of extracellular factor(s) induced by X-irradiation activates the HIV type 1 long terminal repeat through its kappaB motif.
X-irradiation has been used in the treatment of several human diseases, including AIDS-related-malignancies. X-irradiation might induce the transcription and the replication of human immunodeficiency virus type 1 (HIV-1) and enhance nuclear factor kappa B (NF-kappaB). In the present article we show that the activation of the HIV-1 long terminal repeat (LTR) by direct X-irradiation can be mimicked by coculture of transfected cells with X-irradiated nontransfected (HIV-1-negative) cells. In the human colonic carcinoma cell line HT29, the activation seems to depend on an extracellular factor(s) released by a cell line treated with X-rays. The HIV-1 LTR cis-acting element conferring X-indirect responsiveness was identified as the kappaB tandem motif. The two main nuclear HIV-1 kappaB-binding complexes activated by X-direct and -indirect irradiation were the NF-kappaB p50/p65 and c-Rel/p65 heterodimers. Nuclear NF-kappaB activation was dependent on protein neosynthesis. It was partially inhibited by 100 microM pyrrolidine dithiocarbamate, a potent antioxidant drug, but was not correlated with a significant decrease in cellular IkappaBalpha. Furthermore, X-irradiation induces the expression of several cytokine genes generally associated with stress response and antibodies against interleukin 6 and TNF-alpha partially inhibited the X-indirect activation of the HIV-1 LTR. The use of protein kinase C (PKC)-specific inhibitor and of forskolin, an adenylate cyclase activator, suggests that a PKC-dependent pathway and the cAMP intracellular concentration could play a role in the X-indirect enhancement of HIV-1 LTR transcription in the HT29 cell line. In addition, supernatants of an X-irradiated HT29 cell culture activated the HIV-1 stimulation in infected peripheral blood monocytes.
Faure
E
E
UPRES 2202 Biodiversité, ICB, Université de Provence, Marseille, France.
Rameil
P
P
Lecine
P
P
Rey
F
F
Sire
J
J
Kahn-Perles
B
B
Imbert
J
J
D000975:Antioxidants / Q000494:pharmacology; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D016207:Cytokines / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D004742:Enhancer Elements, Genetic; D005110:Extracellular Space / Q000378:metabolism; D016325:HIV Long Terminal Repeat / Q000528:radiation effects*; D015497:HIV-1 / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects*; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism* / Q000528:radiation effects*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D013859:Thiocarbamates / Q000494:pharmacology; D014158:Transcription, Genetic / Q000528:radiation effects; D014764:Viral Proteins / Q000096:biosynthesis; D014779:Virus Replication / Q000528:radiation effects
D000975:Antioxidants; D016207:Cytokines; D004279:DNA, Viral; D007211:Indoles; D008301:Maleimides; D016328:NF-kappa B; D011500:Protein Synthesis Inhibitors; D011759:Pyrrolidines; D013859:Thiocarbamates; D014764:Viral Proteins; D005576:Colforsin; C020972:pyrrolidine dithiocarbamic acid; D003513:Cycloheximide; C070515:bisindolylmaleimide I