Summary. Resveratrol, a natural product present in wine, has recently been shown to inhibit the growth of a number of cancer cell lines in vitro. In the current study, we have demonstrated that resveratrol inhibits the growth of THP-1 human monocytic leukaemia cells in a dose-dependent manner with a median effective dose of 12 mm. It did not induce differentiation of THP-1 cells and had no toxic effect on THP-1 cells that had been induced to differentiate into monocytes/macrophages by phorbol myristate acetate. A significant fraction of resveratrol-treated cells underwent apoptosis as judged by flow cytometric analysis of DNA content, DNA fragmentation and caspase-specific cleavage of poly(ADP-ribosyl) polymerase. Resveratrol treatment had no effect on the expression of Fas receptor or Fas ligand (FasL) in THP-1 cells, nor did it induce clustering of Fas receptors. In addition, THP-1 cells were resistant to activating anti-Fas antibody, and neutralizing anti-Fas and/or anti-FasL antibodies had no protective effect against resveratrol-induced inhibition of THP-1 cell growth. The effect of resveratrol on THP-1 cells was reversible after its removal from the culture medium. These results suggest that (1) resveratrol inhibits the growth of THP-1 cells, at least in part, by inducing apoptosis, (2) resveratrol-induced apoptosis of THP-1 cells is independent of the Fas/FasL signalling pathway and (3) resveratrol does not induce differentation of THP-1 cells and has no toxic effect on differentiated THP-1 cells. Thus, resveratrol may be a potential chemotherapeutic agent for the control of acute monocytic leukaemia.

Tracheal insufflation of tumor necrosis factor (TNF; 5 micrograms or 1.2 x 10(5) U) markedly enhanced the survival of adult rats exposed to 100% O2: 12 of 17 rats (71%) survived for greater than 11 days, whereas 30 of 30 control (Hanks' balanced salt solution) insufflated rats (100%) died within 3 days of O2 exposure. Insufflation of gamma-interferon (5 micrograms) or intraperitoneal injection of up to 40 micrograms TNF did not afford any protection. At 55 h after O2 exposure, TNF-insufflated rats showed less pulmonary edema, as determined by the extravascular lung water content-to-bloodless lung dry weigh ratio and less alveolar capillary leak as determined by the protein content in the bronchoalveolar lavage fluid, than control insufflated rats similarly exposed. This protection against O2 toxicity by TNF insufflation was associated with increased lung superoxide dismutase, catalase, and glutathione peroxidase activities. The enhancement of lung antioxidant enzyme activities was noted at 55 h of O2 exposure, when control animals began to die of O2 toxicity. This temporal relationship suggests that TNF-induced increase in antioxidant enzyme activities contributes, at least in part, to the observed protection.

Endotoxin (LPS) is a potent inducer of tumor necrosis factor-alpha (TNF-alpha) and manganese superoxide dismutase (MnSOD). Recent evidence suggests that LPS induction of TNF-alpha and MnSOD mRNAs is mediated through distinct intracellular signal transduction pathways. Membrane CD14 (mCD14) and Toll-like receptor-4 (TLR4) mediate LPS induction of TNF-alpha in macrophages. In the current study, we evaluated the role of mCD14 and TLR4 in LPS induction of MnSOD using peritoneal macrophages from CD14 knockout (CD14-KO) mice and mice with the Tlr4 gene point mutation (C3H/HeJ) or deletion (C57BL/10ScCr). We studied mCD14-dependent (1 and 10 ng/ml) and mCD14-independent (1,000 ng/ml) concentrations of LPS. Compared with control (BALB/c) macrophages, LPS at 1 and 10 ng/ml failed to induce TNF-alpha or MnSOD mRNA in CD14-KO macrophages. However, LPS at 1,000 ng/ml induced TNF-alpha and MnSOD mRNAs equally in macrophages from CD14-KO and control mice. LPS (1, 10, or 1,000 ng/ml) failed to induce TNF-alpha or MnSOD mRNA and failed to activate nuclear factor-kappaB in C3H/HeJ or C57BL/10ScCr macrophages. Measurements of TNF-alpha and MnSOD enzyme activity paralleled TNF-alpha and MnSOD mRNA levels. These data demonstrate that, like TNF-alpha, induction of MnSOD by LPS is mediated by mCD14 and TLR4 in murine macrophages.

A number of gene delivery methods have been developed to facilitate gene transfer into mammalian somatic cells in vivo. In this study, we demonstrated that tracheal insufflation of two recombinant plasmids containing a bacterial gene, chloramphenicol acetyltransferase (CAT), driven by the cytomegalovirus (CMV) immediate early promoter/enhancer, either alone or complexed to cationic liposomes, resulted in efficient and selective transfection of the lungs in rats. When the simian virus 40 (SV40) promoter/enhancer was used, there was no detectable transfection. Insufflation of plasmid DNA was as efficient as plasmid-liposome complexes in transfecting the lungs. Expression of the CAT gene in the lungs was noted as early as 1 day after insufflation of plasmid DNA alone or plasmid-liposome complexes, and lasted for > 21 days. In contrast, intravenous injection of plasmid alone or plasmid-liposome complexes did not result in transfection of the lungs. Because of its simplicity, without the potential adverse effect of any gene delivery systems, intratracheal delivery of recombinant plasmid DNA may have potential implication for lung-specific gene therapy.

Recent studies have shown that homozygous Mn superoxide dismutase (Sod2) gene-knockout mice (Sod2(-/-)) die shortly after birth with extensive myocardial injury, whereas heterozygous mutants (Sod2(+/-)) are phenotypically normal in room air. In the current study, we showed that Sod2(+/-) mice with approximately 50% of normal pulmonary MnSOD activity and normal levels of lung CuZnSOD, catalase, and glutathione peroxidase activities were not substantially more susceptible to 100% O2 toxicity than their normal Sod2(+/+) littermates. The mean (+/- SD) survival of Sod2(+/-) mice in 100% O2 was 101.4 +/- 14.8 h (n = 20) versus 103.2 +/- 11.3 h (n = 20) for Sod2(+/+) littermates (P > 0.60). In addition, Sod2(+/-) mice with approximately 50% of normal heart MnSOD activity and Sod2(+/+) mice did not develop any ultrastructural abnormalities in the myocardium at 75 h or 90 h after 100% O2 exposure. These results suggest that in mice, only 50% of MnSOD activity may be sufficient for normal resistance to 100% O2 toxicity.