Cholesterol esters as growth regulators of lymphocytic leukaemia cells.

OBJECTIVE: Alterations in plasma lipid profile and in intracellular cholesterol homoeostasis have been described in various malignancies; however, significance of these alterations, if any, in cancer biology is not clear. The aim of the present study was to investigate a possible correlation between alterations in cholesterol metabolism and expansion of leukaemia cell numbers. MATERIALS AND METHODS: Lipid profiles in plasma and in primary leukaemia cells isolated from patients with acute or chronic lymphocytic leukaemia (ALL and CLL) were studied. RESULTS AND CONCLUSIONS: Decreased levels of HDL-C were observed in plasma of leukaemic patients, levels of total cholesterol, LDL-C, triglycerides and phospholipids were unchanged or only slightly increased. As compared to normal lymphocytes, freshly isolated leukaemic cells showed increased levels of cholesterol esters and reduction in free cholesterol. Growth stimulation of ALL and CLL cells with phytohemagglutinin led to further increase in levels of cholesterol esters. Conversely, treatment with an inhibitor of cell proliferation such as the mTOR inhibitor, RAD, caused decline in population growth rate of leukaemia cells, which was preceded by sharp reduction in rate of cholesterol esterification. On the other hand, exposure of leukaemic cells to two inhibitors of cholesterol esterification, progesterone and SaH 58-035, caused 60% reduction in their proliferation rate. In addition to demonstrating tight correlation between cell number expansion and cholesterol esterification in leukaemic cells, these results suggest that pathways that control cholesterol esterification might represent a promising targets for novel anticancer strategies.

Comparative analysis of polyphenolic profiles and antioxidant and antimicrobial activities of tunisian pome fruit pulp and peel aqueous acetone extracts.

Pome trees, apple, pear, and quince, are classified into the subfamily Pomoideae, belonging to the Rosaceae family. Their autumnal fruits are consumed worldwide in different forms, that is, fresh or transformed into jams, jelly, juices, etc. Their well-established beneficial properties to human health were found mainly related to their phenolic content. Pulp and peel aqueous acetone extracts obtained from Tunisian fruits at commercial maturity were comparatively evaluated for their phenolic profiles and antioxidant and antimicrobial potentials. The phenolic compounds present in the extracts were identified and quantified using RP-HPLC-DAD and ESI-MS techniques. Significant differences in the chromatographic profiles among these fruits, as well as between pulp and peel extracts of each fruit, were observed. Quince, followed by 'Red Delicious', peel extracts showed the highest phenolic content (160.33 and 110.90 mg/100 g of fresh weight). The stronger inhibitory effect on DPPH radicals corresponded to those obtained from peel materials. A comparative analysis of the antimicrobial potential against a range of microorganism strains was also carried out. Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus cereus were the most sensitive to the active extracts. Among the examined phenolic extracts, 'Red Delicious' and quince peels showed the highest effects for inhibiting bacteria growth. Minimum inhibitory and bactericide concentrations ranged from 10(2) to 10(4) microg of polyphenol/mL. Red skin apple and quince peels could be of great interest as important antioxidant and antimicrobial polyphenol sources.

Lipid metabolism and molecular changes in normal and atherosclerotic vessels.

OBJECTIVES: a positive correlation between cholesterol esterification, acyl-CoA:cholesterol acyltransferase (ACAT), multidrug resistance (MDR1) gene expression and atherosclerotic lesions has been shown in human arteries. The objective of this study was to map the expression of MDR1, ACAT genes and the cholesteryl ester content in normal, atherosclerotic and varicose human vessels. MATERIALS: vascular segments were obtained from seven cadaveric donors, 27 patients undergoing vascular surgery for severe atherosclerotic disease and 11 patients with saphenous vein varicosities. METHODS: lipid analysis and RT-PCR of MDR1 and ACAT mRNAs were performed. RESULTS: an increase in cholesteryl ester content and in ACAT and MDR1 expression was demonstrated in relation to the age in the arteries prone to atherosclerosis; this expression was maximal in arteries from symptomatic patients. In resistant arteries and in veins cholesteryl ester accumulation was rare and light, while ACAT and MDR1 expression was not related to the age of the subjects. CONCLUSIONS: the results showed that an increase in MDR1 and ACAT expression may be responsible for the accumulation of cholesteryl esters as well as for cell growth rate acceleration in vessel sites prone to atherosclerosis.

Intra- and intercellular distribution of mitochondrial probes and changes after treatment with MDR modulators.

Fluorescent probes are currently used to evaluate the mitochondrial transmembrane potential in situ. However, in parallel experiments using the probes JC-1 and TMRM in different cell types (human astrocytes, HEp-2, Vero, KB, and HeLa cells), we found that the distribution of JC-1 and TMRM is highly variable not only in different cell types but also in different cells of the same cell type, a condition that has never been documented until our work. This phenomenon depends on a hidden, widespread multidrug resistance (MDR) phenotype that can be recognized only by comparative assays with MDR inhibitors (progesterone, verapamil, and cyclosporin A) and represents a serious risk of error in the evaluation of the mitochondrial potential.

G6PD activity and gene expression in leukemic cells from G6PD-deficient subjects.

In the present study we examined gene expression and glucose-6-phosphate dehydrogenase (G6PD) activity in leukemic cells isolated from G6PD normal and deficient subjects. The results have shown that G6PD activity strongly increases in G6PD normal leukemic cells as well as in G6PD deficient leukemic cells when compared to peripheral blood mononuclear cells (PBMC). Higher levels of G6PD gene expression were observed in leukemic cells from G6PD deficient patients compared to G6PD normal. A similar pattern of gene expression was also observed for 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase. These results support the hypothesis that G6PD deficient cell, in order to sustain their growth, must respond to the low activity of their mutant enzyme with an increase in quantity through an induction of gene expression.

Correlation between cholesterol esterification, MDR1 gene expression and rate of cell proliferation in CEM and MOLT4 cell lines.

A positive correlation between cholesterol esterification and growth rate potential was previously found in our laboratory during the growth of CEM and MOLT4 lymphoblastic cells. In the current study, we investigated whether the rates of cholesterol esters synthesis correlate with changes of acyl-CoAcholesterol acyltransferase (ACAT) mRNA levels and of other genes implied in cholesterol biosynthesis and uptake, such as 3-hydroxy-3-methylglutaryl-CoA (HMGCoA) reductase and low density lipoprotein (LDL) receptor. The results showed that the more rapid growing CEM cells had lower levels of expression of HMGCoA-reductase and LDL receptors compared to MOLT4. By contrast, ACAT mRNA levels were higher in CEM cells, further supporting the concept of a possible involvement of cholesterol esters in the regulation of cell growth and division. In this study, high levels of cholesterol esterification and of expression of ACAT gene were also associated with a markedly increased expression of multidrug resistance (MDR1) gene, suggesting that MDR1 activity might contribute to regulate the rate of cell growth and division by modulating intracellular cholesterol ester levels.

Alterations of lipid and cholesterol metabolism in cachectic tumor-bearing rats are prevented by insulin.

The ascites hepatoma Yoshida AH130 causes in the host a rapid and progressive body weight loss, associated with reduced food intake, and protein and lipid hypercatabolism. Because insulin regulates glucose as well as lipid and protein metabolism, we suggest that the observed alterations are at least in part secondary to hypoinsulinemia and/or to the increase of counterregulatory hormones in AH130-bearing rats. To verify this hypothesis, controls with free access to food (n = 4), controls with free access to food plus insulin (107 micromol. kg body wt-1. d-1) (n = 4), controls pair-fed to the tumor-bearing rats (n = 4), pair-fed controls treated with insulin (n= 4), tumor hosts (n = 9), and tumor hosts treated with insulin (n = 6) were used. The Yoshida ascites hepatoma cells ( approximately 10(8) cells/rat) were inoculated intraperitoneally. Daily food intake and body weight were measured; insulin was injected starting the day of tumor implantation for 6 d. The metabolism of both cholesterol and lipids was investigated in tumor cells, and ascitic fluid and blood serum were investigated at the end of treatment. Insulin prevented the reduction of food intake (19 +/- 0.6 vs. 13 +/- 0.4 g/d, P < 0.01; AH130 hosts treated and not treated with insulin, respectively), the loss of body weight (202 +/- 12 vs. 135 +/- 9 g, P < 0.01), lowered the circulating triglycerides (48.3 +/- 4.9 vs. 84.5 +/- 7.1 mmol/L, P < 0.01), and free fatty acids (561 +/- 47 vs. 989 +/- 54 mmol/L (P < 0.01), while corrected the decrease of adipose lipoprotein lipase activity (1,240 +/- vs. 300 +/- pmol FA, P < 0.01) observed in AH130 hosts. Moreover, insulin prevented the decrease in HDL cholesterol (13.2 +/- 0.8 vs. 9.3. +/- 0.7 mmol/L, P < 0.01) and significantly increased hepatic cholesterol synthesis as evaluated by 14C-acetate incorporation into cholesterol, in both liver (3,337 +/- 245 vs. 830 +/- 115 Bq/g, P < 0.01) and AH130 cells (11,676 +/- 1,693 vs. 4,196 +/- 527 Bq/10(6) cells, P < 0.01). Thus insulin treatment ameliorated many metabolic derangements, with a lengthening of rats survival time (7 +/- 1 vs. 11 +/- 1 d, P < 0.05) without significantly stimulating tumor growth. These data, together with our previous observations on the effectiveness of insulin on protein turnover perturbations, suggest that many metabolic alterations occurring during cancer cachexia can be avoided by the administration of this hormone.

Role of cholesterol synthesis and esterification in the growth of CEM and MOLT4 lymphoblastic cells.

CEM and MOLT4 are human T-cell lines isolated from patients with acute cell leukaemia. In culture they show important differences in cholesterol metabolism, CEM being less efficient at synthesizing cholesterol and having a lower activity of 3-hydroxy-3-methylglutaryl-CoA (HMGCoA) reductase. To investigate further the relationship between regulation of intracellular cholesterol metabolism at various steps and rate of cell growth, cholesterol synthesis, esterification and efflux were evaluated in CEM and MOLT4 cells at different times during exponential and stationary growth in vitro. It was shown that, although CEM cells have a lower rate of cholesterol synthesis, they grow at a faster rate than MOLT4 cells. However, CEM cells exhibit an increased capacity to esterify cholesterol associated with a decreased efflux of newly synthesized cholesterol into the medium. These results provide evidence for an association between the capability to synthesize and retain cell cholesterol esters and the growth rate potential.

Perturbations of triglycerides but not of cholesterol metabolism are prevented by anti-tumour necrosis factor treatment in rats bearing an ascites hepatoma (Yoshida AH-130).

Rats transplanted with the ascites hepatoma Yoshida AH-130 developed a severely progressive cachexia, characterised by marked alterations in protein and lipid metabolism. In particular, high levels of serum triglycerides and free fatty acids were associated with altered levels and distribution of plasma cholesterol, with increased total and very low-density lipoprotein-low-density lipoprotein (VLDL-LDL) cholesterol and reduced high-density lipoprotein (HDL) cholesterol. The tumour cells showed high rates of cholesterol synthesis and elevated content of free and esterified cholesterol, whereas total cholesterol synthesis was reduced in the host liver. To determine whether these perturbations could be related to the elevation of tumour necrosis factor alpha (TNF-alpha) previously shown in the AH-130 bearers (Tessitore L, Costelli P, Baccino FM 1993, Br J Cancer, 67, 15-23), either anti-TNF polyclonal antibodies or non-immune IgGs were injected daily after tumour transplantation. The anti-TNF treatment neither affected tumour growth nor prevented the serum cholesterol changes, while attenuating the hypertriglyceridaemia and the elevated serum free fatty acid levels. These data indicate that TNF does not appear to be directly involved in the altered cholesterol metabolism in AH-130 hosts, thus supporting the view that cholesterol metabolism and lipid metabolism are regulated differently during tumour growth.

Clinical remission is associated with restoration of normal high-density lipoprotein cholesterol levels in children with malignancies.

1. Serum lipids and lipoprotein profiles were determined in children affected by different types of malignancies (leukaemias or lymphomas and solid tumours) both before any treatment and after remission of the disease following chemical or surgical therapy. 2. At the time of diagnosis, children bearing tumours showed hypertriglyceridaemia and reduced concentrations of plasma high-density lipoprotein cholesterol levels, the decrease being particularly prominent in patients with haematological tumours. Children bearing solid tumours displayed an increase of total cholesterol, while those with haematological cancer showed decreased phospholipid levels; low-density lipoprotein cholesterol in neoplastic patients was not significantly different from control values. High triacylglycerol and low high-density lipoprotein cholesterol levels were also evident in cancer patients divided according to age into three groups (0-5, 6-10 and 11-15 years) when compared with age-matched control subjects. Similarly, high triacylglycerol and low high-density lipoprotein cholesterol levels were also observed in both male and female children when patients were divided according to sex and compared with corresponding controls. 3. Clinical remission after therapy was accompanied by an increase of high-density lipoprotein cholesterol levels compared with values observed at diagnosis. In contrast, post-treatment levels of triacylglycerol were higher than those observed before therapy. These results support the hypothesis that alterations of high-density lipoprotein cholesterol levels may be related, at least in part, to the rate of tumour growth, while modifications of triacylglycerol levels may be mediated by different mechanisms.

HDL subfractions as altered in cancer patients.

Previous studies from the authors' laboratories have shown that cancer patients are characterized by lower levels of high-density lipoprotein cholesterol (HDL-C) compared with those of normal subjects. HDLs are a complex class of lipoproteins which can be divided mainly into two categories, HDL2 and HDL3, that have not only different lipid and protein composition but also different functions. Therefore, for a better understanding of the metabolism of HDL during tumour growth, the different subfractions of HDL (HDL2 and HDL3) were analysed in the serum of neoplastic patients using a rapid and simple high-performance liquid chromatography (HPLC) method for the analysis. The results obtained showed that serum from neoplastic patients exhibits a peculiar pattern in the distribution of HDL subfractions, consisting of a sharp decrease in HDL3 and a consequent increase of the normal HDL2/HDL3 ratio. It is suggested that evaluation of the HDL subfractions may be of clinical relevance for cancer status and that due to its simplicity, short analytical time and small sample volume required, the HPLC technique used in this study can be easily applied to routine analysis in cancer patients.

Survey on the prevalence of leptospira infections in the Italian population.

This investigation is the first nationwide survey on the circulation of leptospira infections in human beings in Italy. In nine out of twenty Italian regions, representative samples of the population were investigated for the presence of leptospira infections. Unexpectedly, leptospira infections were found to be widespread, the number of cases being much higher than the diagnosed clinical cases. There were found to be high, medium, and low risk areas. On the whole, the risk for the rural population was no higher than the risk for urban dwellers; leisure activities, contact with animals and residence on the plain versus residence in the hills were important risk factors. There was an unidentified risk factor in urbanites which was absent in the rural population. A changing pattern in infecting serovars was observed, with infections from serogroups Sejroe, Javanica and Australis prevailing over infections from the Icterohaemorrhagiae and Bataviae serogroups, which were the main agents of human leptospirosis during the 1950s. The mechanisms of these changes, the need for epidemiological surveys and improved diagnostic methods of screening are discussed.

Cholesterol content in tumor tissues is inversely associated with high-density lipoprotein cholesterol in serum in patients with gastrointestinal cancer.

BACKGROUND: The authors have previously demonstrated in different experimental models that sustained processes of cellular growth are characterized by alterations of cholesterol metabolism not only in the proliferating tissues but also in the plasma compartment. METHODS: To evaluate whether alterations of cholesterol metabolism similar to those observed in experimental models are also associated with human cancer, in the present study cholesterol distribution in tumor tissues and lipid composition in the plasma compartment were determined in patients with different types of gastrointestinal cancer. RESULTS: The results showed that tumor tissues contain increased amounts of cholesterol when compared with the corresponding normal tissues. Intracellular alterations of cholesterol were accompanied by specific changes of cholesterol in the plasma compartment: high-density lipoprotein (HDL) cholesterol was markedly reduced in the serum of patients with gastrointestinal cancer and the lipoprotein profiles showed a decrease in HDL3 fraction, the main HDL subfraction in human serum. The decrease of HDL cholesterol was negatively associated with the clinical stage of the disease. No changes in either total or low-density lipoprotein cholesterol levels were observed. CONCLUSIONS: A major function attributed to HDL is to maintain normal cell cholesterol homeostasis by removing excess of cholesterol from intracellular pools. Because the use and storage of cholesterol are increased within the tumor tissues during growth, it is possible to hypothesize that low HDL levels observed in patients with gastrointestinal cancer are associated with the increased cholesterol metabolism in proliferating tissues.

Cholesterol metabolism during the growth of a rat ascites hepatoma (Yoshida AH-130).

The metabolism of cholesterol has been investigated in tumour cells, ascitic fluid and blood serum during the growth of an ascites hepatoma (Yoshida AH-130) in the rat. High rates of cholesterol synthesis and elevated free and esterified cholesterol content were observed in tumour cells. During tumour growth, the host animals progressively developed marked changes in the level and distribution of serum cholesterol consisting in an increase of total cholesterol and of a marked reduction of HDL cholesterol (HDL2 subfraction in particular). In agreement with previous observations, these findings indicate that a consistent pattern of altered cholesterol homeostasis develops in relation to normal or neoplastic tissue growth. High synthetic rates and intracellular accumulation of cholesterol are observed in the proliferating cells. Moreover, blood serum cholesterol decreases in the HDL fraction while it increases in LDLs, suggesting that during proliferative processes cholesterol fluxes between tissues and serum lipoproteins are markedly perturbed.

Serum lipoprotein pattern as modified in G6PD-deficient children during haemolytic anaemia induced by fava bean ingestion.

In the present study, plasma lipid concentrations were determined at different times after admission in sera from G6PD-deficient children during haemolytic crisis induced by fava bean ingestion. Reductions in total, LDL and HDL cholesterol were found in association with the maximum of bone marrow hyperplasia. A return towards normal values occurred with regression of the disease. No changes in other lipid parameters were observed. These data suggest that alterations of lipoprotein pattern, other than in experimental animals, are also present in humans with non-malignant proliferative processes. These changes appear to be a consequence of the disease, probably due to an increased utilization of cholesterol by proliferating cells.

Altered pattern of lipid metabolism in patients with lung cancer.

Cholesterol distribution in tumoral tissues and lipid composition in the plasma compartment were determined in patients affected by different histologic types of lung cancer. The results showed that tumoral lung tissues contained 2-fold more total cholesterol and 3.5-fold more esterified cholesterol than normal lung tissues. In the patients the alterations in intracellular cholesterol were also associated with peculiar changes in cholesterol distribution in the plasma compartment. Serum high-density lipoprotein (HDL) cholesterol levels were markedly lower in than in controls. No significant changes in other lipid parameters were observed in these patients. We suggest that the reduced levels of serum HDL cholesterol observed in patients with lung tumors may be a consequence of the disease, probably mediated by the greater utilization of cholesterol for new membrane biogenesis and by the accumulation of esterified cholesterol in tumoral tissues.

Total and HDL cholesterol in human hematologic neoplasms.

In this study serum cholesterol was measured in different types of human hematologic malignancies characterized by a wide range of cell proliferation. In all tumoral types a significant decrease of HDL cholesterol was observed, whereas total serum cholesterol generally remained unchanged. Another interesting observation of our study was the apparent inverse correlation between the extent of cell proliferation in these neoplastic disorders and the level of HDL cholesterol. Since a decrease of HDL cholesterol was previously observed, in our laboratory, in different experimental models of normal and neoplastic cell proliferation, we suggest that the decrease of HDL cholesterol may be a generalized phenomenon related to massive cellular growth in normal and malignant processes.

Serum lipoproteins during bone marrow hyperplasia after phenylhydrazine administration in rats.

In the present study, lipoprotein metabolism was investigated during compensatory hyperplasia of bone marrow after haemolysis induced by phenylhydrazine (20 mg/kg b.w.) administration in rats. The rats were sacrificed at different time intervals (0, 1, 2 and 5 days) after phenylhydrazine treatment. Analysis of the different fractions of lipoproteins has shown that during bone marrow hyperplasia there is an alteration of lipoprotein profiles, mainly due to a decrease of HDL2 and HDL3 subfractions.