Effect of 4-Hydroxynonenal on cell cycle progression and expression of differentiation-associated antigens in HL-60 cells.

4-Hydroxynonenal (HNE) is a highly reactive aldehyde produced by lipid peroxidation of cellular membranes that inhibits growth and induces differentiation in HL-60 cells. Its mechanisms of action were investigated by analyzing the cell cycle distribution and the appearance of differentiated phenotypes in HL-60 cells. Data obtained by exposing cells to DMSO for 7.5 h (same time as for HNE treatment) or for the whole length of the experiments (5 d) were used for comparison. HNE induced a marked increase in the proportion of G0/G1 cells after 1 and 2 d. The brief DMSO treatment did not affect the distribution, whereas continuous exposure led to a progressive accumulation of cells in G0/G1 (maximal at day 5). The proportion of phagocytic cells gradually increased in HNE-treated and DMSO long-exposed cultures from day 2 and peaked at day 5 (35 and 63%, respectively), whereas the effect of the brief DMSO treatment was negligible. The expression of CD11b and CD67 increased in cells treated with HNE or continuously exposed to DMSO, whereas CD36 was expressed at low levels on both treatments. These results indicate that the pathway of the granulocytic differentiation induced by HNE in HL-60 cells differs from that of DMSO: with HNE, growth inhibition precedes the onset of differentiation, whereas in DMSO-treated cells the two processes are chronologically associated.

Inhibition of c-myc expression induced by 4-hydroxynonenal, a product of lipid peroxidation, in the HL-60 human leukemic cell line.

4-Hydroxynonenal is a highly reactive aldehyde, produced by cellular lipid peroxidation, able to inhibit cell proliferation "in vitro" and "in vivo". Its concentration in non proliferating cells ranges up to 1 microM, whereas in the highly undifferentiated tumour cells, it is very low or undetectable. We have now demonstrated that micromolar concentrations of 4-hydroxynonenal inhibit c-myc but not N-ras expression in HL-60 human leukemic cells. This inhibitory effect is observed after an incubation of 1 hour with both 1 and 10 microM aldehyde. Moreover, we report that down-regulation of c-myc expression increases when repeated additions of 1 microM 4-hydroxynonenal are performed, to maintain the cells in presence of aldehyde for 7.5 hours. These results indicate that not only the concentration but also the length of exposure to the aldehyde is important in determining the extent of the c-myc expression inhibition and suggest a role of lipid peroxidation products in the control of gene expression.

[Abnormal erythrocyte sodium transport in patients with adult polycystic kidney and hypertension]. / Altérations du transport érythrocytaire du sodium chez les patients atteints de polykystose rénale de l'adulte et hypertension artérielle.

The aim of this work was to evaluate the intracellular Na concentration, the passive Na permeability and the activity of Na, K pump, Na, K cotransport, Na, Li countertransport in the red cells of patients with autosomal dominant polycystic kidney disease (ADPKD) in relationship with their blood pressure status. Sixteen patients with ADPKD and normal renal function (6 males, 10 females, median age 31.5 years, range 20-42 years) and twenty healthy controls (10 males, 10 females, median age 30 years, range 23-47 years) were studied. Eight ADPKD were hypertensive. The rate constant of ouabain-sensitive Na efflux was lower in hypertensive than in normotensive ADPKD patients. The activity of Na,Li countertransport was significantly higher in hypertensive ADPKD patients than in both normotensive patients and control subjects. A significant inverse correlation was found between Na,Li countertransport activity and the rate constant of ouabain-sensitive Na efflux in fresh red cells (rho = 0.62; p = 0.016). Hypertension in patients with ADPKD and normal renal function is associated with abnormalities of red cell sodium transport: an increase of Na,Li countertransport, possibly primitive, and a reduction of Na,K pump in fresh cells, possibly secondary to a circulating inhibitor.

Vitamin E dietary supplementation inhibits transforming growth factor beta 1 gene expression in the rat liver.

Overexpression of transforming growth factor beta 1 (TGF beta 1) and increased transcription of pro-collagen type I, are known to represent major events implicated in the development of liver fibrosis under either experimental or clinical conditions. Here we report that long-term dietary vitamin E supplementation in animals undergoing an experimental model of liver fibrosis (induced by chronic treatment of rats with carbon tetrachloride) results in a net inhibition of both hepatic TGF beta 1 and alpha 2 (I) procollagen mRNA levels. Moreover, of striking interest is the observation that vitamin E supplementation per so down-modulates basal levels of TGF beta 1 mRNA in the liver of untreated animals, suggesting that a dietary regimen rich in vitamin E may potentially interfere with both the initiation and progression of the fibrosclerotic processes.

Induction of differentiation in human HL-60 cells by 4-hydroxynonenal, a product of lipid peroxidation.

4-Hydroxynonenal (HNE) is the major diffusible toxic product generated by lipid peroxidation of cellular membranes. The level of lipid peroxidation and, consequently, the concentration of its products are inversely related to the rate of cell proliferation and directly related to the level of cell differentiation. In the present paper the effects of HNE on the proliferation and differentiation of the HL-60 human promyelocytic cell line have been investigated. Repeated treatment at 45-min intervals with HNE (1 microM) was performed to maintain the cells in the presence of the aldehyde for 7 1/2 or 9 h. The effect of HNE on cell proliferation and differentiation was compared with dimethyl sulfoxide (DMSO)-treated cells. HNE causes a strong inhibition of cell growth without affecting cell viability. Moreover, HL-60 cells acquire the capability to produce chemiluminescence after soluble (phorbol myristate acetate) or corpuscolate (zymosan) stimulation. The phagocytic ability has also been calculated by counting the number of cells that phagocytize opsonized zymosan. Values were 43 and 55% after 10 or 12 HNE treatments, respectively, and 88% in DMSO-treated cells. Myeloperoxidase activity, 5 days after treatment, decreased by 85% in either HNE- or DMSO-treated cells while acid phosphatase activity increased with respect to untreated cells. Results obtained indicate that HNE at concentrations close to those found in the normal tissues can induce inhibition of proliferation and induction of differentiation in the HL-60 cell line.

c-erbB-2 and ras expression levels in breast cancer are correlated and show a co-operative association with unfavorable clinical outcome.

c-erbB-2 and ras expression was measured on tumor extracts from 132 human primary breast carcinomas, by immunoblotting analysis. Expression of the c-erbB-2-encoded p185 protein was observed in 39% of the samples and found to correlate with c-erbB-2 gene amplification, detected by Southern analysis in 19 of the 77 available tumor DNAs. p185 expression was linked to the absence of progesterone receptors, but it was not related to lymph-node status or to other clinico-pathological parameters. Levels of the ras-encoded p21 proteins higher than in normal breast tissues were found in 71% of the samples. No significant correlation was seen between p21 level and the available clinical parameters. Conversely, there was a strong positive correlation between p21 and p185 levels. Analysis of follow-up data revealed that p185 expression was associated with a shorter time to relapse and death. Most notably, the contemporaneous expression of p185 and of high p21 levels was more effective than p185 expression alone in identifying cases with poor prognosis. The prognostic value of p185/p21 co-expression was particularly significant in progesterone-receptor-positive tumors. Our data suggest that c-erbB-2 and ras may act synergistically to endow breast-tumor cells with a highly aggressive phenotype.