[Vitamin D anti-cancer activities: observations, doubts and certainties]

The importance of vitamin D in bone and phosphocalcic status is well recognized by the scientific and medical communities; however, recently identified properties of this cholesterol derived molecule, such as immunomodulator and anticancer activities, are yet discussed. Actually, the debate is not so much about the new vitamin D properties, but rather about the optimal concentration required to reach these properties. The difficulty in determining the norms is rendered even more complex by the existence of a vitamin D receptor gene polymorphism. The body pool of this vitamin depends essentially on its endogenous synthesis, but also on its dietary intakes. Many epidemiological studies interested in Vitamin D serum level and cancer suggest a relation between low Vitamin D level and cancer risk, especially in breast and colon adenocarcinomas. In vitro, many studies showed, in different human and animal malignant cell lines, that this molecule exerts anticancer activities: it induces apoptosis and cell differentiation as well as it inhibits proliferation and angiogenesis. This review tries to update the current knowledge on vitamin D and, more particularly, the potential interest of this molecule in cancer prevention and management.

HDAC5 is required for maintenance of pericentric heterochromatin, and controls cell-cycle progression and survival of human cancer cells

Histone deacetylases (HDACs) form a family of enzymes, which have fundamental roles in the epigenetic regulation of gene expression and contribute to the growth, differentiation, and apoptosis of cancer cells. In this study, we further investigated the biological function of HDAC5 in cancer cells. We found HDAC5 is associated with actively replicating pericentric heterochromatin during late S phase. We demonstrated that specific depletion of HDAC5 by RNA interference resulted in profound changes in the heterochromatin structure and slowed down ongoing replication forks. This defect in heterochromatin maintenance and assembly are sensed by DNA damage checkpoint pathways, which triggered cancer cells to autophagy and apoptosis, and arrested their growth both in vitro and in vivo. Finally, we also demonstrated that HDAC5 depletion led to enhanced sensitivity of DNA to DNA-damaging agents, suggesting that heterochromatin de-condensation induced by histone HDAC5 silencing may enhance the efficacy of cytotoxic agents that act by targeting DNA in vitro. Together, these results highlighted for the first time an unrecognized link between HDAC5 and the maintenance/assembly of heterochromatin structure, and demonstrated that its specific inhibition might contribute to increase the efficacy of DNA alteration-based cancer therapies in clinic.

[Autologous fat grafting in the breast: oncological implications]

Autologous fat grafting for breast is increasing dramatically. This fat injection needs accurate technical conditions, and shows very good and long-lasting clinical results. Nevertheless, in breast conservative treatment sequellae, fat injection could lead to difficulties in breast imaging, but also there is some concerns about the potential oncologic risks of these procedures.

Induction of apoptosis in human promyelocytic leukemia cells by a natural trachylobane diterpene

BACKGROUND

Trachylobane diterpenes are secondary metabolites, quite rare in nature, and their bioactivities are poorly understood. Recently, we have described the cytotoxic activity of ent-trachyloban-3beta-ol isolated from the leaves of Croton zambesicus, a plant used in African folk medicine.

MATERIALS AND METHODS

Cell viability on several cell lines, cell morphology, DNA laddering, annexin Vand caspase-3 activation experiments were undertaken in order to analyse the cytotoxicty of trachylobane diterpene and to determine if this compound is able to induce apoptosis.

RESULTS

ent-Trachyloban-3beta-ol exerts a dose-dependent cytotoxic effect, which varies between cell lines. Induction of apoptosis in HL-60 cells could be detected at a concentration of 50 microM after 24-h treatment.

CONCLUSION

We show here, for the first time, that a trachylobane diterpene is able to induce apoptosis in human promyelocytic leukemia cells via caspase-3 activation in a concentration-dependent manner.

Age, sex, and weight at weaning influence organ weight and gastrointestinal development of weanling pigs

The present study was designed to determine the interrelationships between sex, weaning age, and weaning weight on aspects of physiological and gastrointestinal development in pigs. Forty-eight Large White × Landrace pigs were used in a factorial arrangement with the respective factors being: age at weaning (14 or 28 days), weight at weaning (heavy or light), sex (boar or gilt), and time after weaning (1, 7, and 14 days). At weaning, 48 pigs were removed from the sow: 16 pigs were then fasted for 24 h before euthanasia for determination of organ weights, gut histology, and enzymology, and 32 pigs were offered a high quality pelleted weaner diet ad libitum for subsequent assessment of organ weights, histology, and enzymology at 7 and 14 d after weaning. On Day 6 and 13 after weaning, 2 pigs from each group had their feed removed, and 24 h later were euthanased and similar measurements were taken. In general, the data highlighted the overall gastrointestinal underdevelopment of pigs weaned at 2 weeks of age and of pigs weaned light-for-age at either 2 or 4 weeks. Heavier body organs, gastrointestinal organs, and accessory digestive organs observed after weaning, except for the spleen, presumably reflected the increase in substrates available for cellular growth as feed intake increased after weaning, and the development of organs required to process this feed. Interestingly, the relative weights (% of liveweight) of the stomach and small intestine and, to a lesser extent, the caecum and colon, were greater in the light, 14-day-old weaned pigs, but these differences diminished with increasing time after weaning. Consistent effects due to age, weight, and sex were not observed for villous height and crypt depth, or for the specific activities of the brush-border and pancreatic enzymes measured. However, increases (P < 0.001) in the activities of maltase (P�<�0.001), glucoamylase (P < 0.001), and sucrase (P = 0.020) (all expressed per gram of mucosa), and that of trypsin (per gram of pancreas), occurred by 14 days after weaning. This most likely reflected the inducible nature of these enzymes in response to the increasing intake of substrates provided in the diet. In contrast, the specific activity of lactase declined (P = 0.012) in the first 14 days after weaning. These data suggest that pigs weaned at 2 weeks of age and pigs weaned light-for-age at either 2 or 4 weeks have a less developed gastrointestinal tract, and that its development after weaning might proceed differently to that of pigs weaned older and heavier.

Spermine induces precocious development of the spleen in mice

Spermine is a low molecular weight polyamine involved in the postnatal maturation of the gut. When it is administered orally to suckling rats, it induces maturation of the intestinal tract (liver, pancreas and small intestine). Here we show that this polyamine is able to induce precocious intestinal and splenic development in suckling mice. In fact, in 15-day-old mice which had received spermine orally twice daily for 3 days we observed an increase in the ratio of white pulp surface to total spleen surface in comparison with untreated mice. The two macrophage subsets of the marginal zone and the B-cell population were more developed and reached the development level of 5- or 10-week-old mice. The proliferation rate of B-cells was increased by spermine administration to pups. These observations suggest that spermine might play a role in immune system development; further investigation of its effects are intended, namely the evaluation of its capacity to enhance defence during the neonatal period.

Spermine-Induced alteration of small intestine in suckling rat: involvement of apoptosis or Zn2+ enzymes?

Polyamines are of great importance in several physiological processes, such as cell proliferation and differentiation. The ingestion of spermine by suckling rats induces precocious maturation of their small intestine. Shortly after ingestion, spermine produces cell elimination at the villous top. The origin of this exfoliation was investigated to determine whether it was due to apoptosis. Wistar rats were orally treated with spermine. Apoptosis was analyzed in their small intestine by Tdt-mediated dUTP-fluorescein nick-end labeling reaction, caspase-3-like analysis, and DNA laddering. Polyamine content was measured by HPLC. The intestinal transitory alteration appeared as soon as 2 hr after spermine administration. Apoptosis events increased strongly at the same moment in the small intestine. They were evidenced by Tdt-mediated dUTP-fluorescein nick-end labeling analysis, DNA laddering, and caspase-3-like activity. Changes observed are consistent with apoptosis, but caspase inhibitor did not reduce intestinal alteration, as did Zn2+ chelator.

Dietary polyamines and non-neoplastic growth and disease

This review presents the data that are now available concerning the effects of dietary polyamines at either postnatal or adult stages in non-neoplastic growth and disease. Polyamines provided by food have a potential role in growth and development of the digestive system in neonatal mammals (and fishes). In humans, this property could be of importance in preventing the appearance of food allergies. Dietary polyamines also seem necessary for the maintenance of normal growth and general properties of adult digestive tract. Their possible therapeutic effects have been investigated in gastric, intestinal, and, more recently, whole-body healing.

Cyclosporine A inhibits partially spermine-induced differentiation but not cell loss of suckling rat small intestine

The polyamines are of great importance in several biological processes, such as cell proliferation, and differentiation. The ingestion of spermine by suckling rats induces the precocious maturation of their small intestine. This phenomenon is preceded by a cell elimination at the villus tip. We hypothesize that these two phenomena could be mediated by the immune system and thus inhibited by an immunosuppressive agent such as cyclosporine A. Cyclosporine A inhibits, at least partially, the spermine-induced increase of the maltase- and sucrase-specific activities in the small intestine but failed to inhibit lactase-specific activity decrease and cell loss. Spermine does not act by the same mechanism in differentiation and in cell loss. Moreover, spermine acts in a different way on lactase-specific activity compared to maltase- or sucrase-specific activity. We hypothesize that spermine acts on differentiation by a T-cell/IL-2-dependent mechanism.

Are milk polyamines preventive agents against food allergy?

Insufficient polyamine intake could play a role in the induction of sensitization to dietary allergens. This proposal is based essentially on investigations made in sucking rats and in children. In sucking rats it has been established that oral administration of spermine can induce all the modifications occurring in the digestive tract at weaning. In the intestine events occur in two phases. The early event consists of desquamation of the epithelium resulting from an activation of apoptosis. The late event appears to involve an hormonal cascade in which adrenocorticotropic hormone, cytokines, bombesin and corticosterone are included. Observations in human subjects show that: (1) the spermine and spermidine concentrations are generally lower in infant formulas than in human breast milk. Mothers seem consistently to have relatively high or relatively low concentrations of spermine and spermidine in their milk. These individual variations may be due to diet, lifestyle or genetic background; (2) the probability of developing allergy can reach 80 % if the mean spermine concentration in the milk is lower than 2 nmol/ml milk. It is approximately 0 % if the mean spermine concentration is higher than 13 nmol/ml milk; (3) preliminary results show that the intestinal permeability to macromolecules differs in premature babies when they are fed on breast milk compared with infant formulas (J Senterre, J Rigo, G Forget, G Dandrifosse and N Romain, unpublished results). This difference does not seem to be present when powdered milk is supplemented with polyamines at the concentration found in breast milk; (4) spermine increases proliferation and differentiation of lymphocytes isolated from the tonsils of children.

[Statement on polyamines]

Polyamines are ubiquitous substances. Their intracellular concentration is controlled quickly and rigorously by extremely sophisticated systems. It depends on metabolism and cellular permeability. Polyamines act as structural and functional elements in the cell (nucleic acid conformation, cytoskeleton, radioprotection, apoptosis, proliferation and differentiation of cells...). They also play a role in various diseases (origin of food allergy, cancers...). They present a great therapeutic interest (oncology, molecular transfer to cell nucleus, transfer across the blood-brain barrier, parasitosis, effects on NMDA and GABA receptors in the central nervous system...).

The relationship between spermine content of human milk during the first postnatal month and allergy in children

DESIGN

Qualitative case study and mathematical model.

SETTING

Belgium.

OBJECTIVES

To evaluate the correlation between the polyamine mean concentration of the milk drunk during the first postnatal month and the appearance of allergy in children who drank this milk.

RESULTS

A model that describes the dependence of the allergy appearance with the spermine mean concentration of milk drunk during the first postnatal month was established.

CONCLUSIONS

This model shows that 5.02 nmol ml(-1) of spermine is a critical value to prevent the appearance of allergy.

Comparison between the natural postnatal maturation and the spermine-induced maturation of the rat intestine

In the suckling rats, orally provided spermine induced structural and biochemical changes in the intestine, which are characteristics of the postnatal maturation. This induced maturation was compared to that occurring spontaneously. Eight mumol spermine were administered orally once a day, for one or three days, to suckling rats which were 11 days old at the beginning of the experiment. The animals were killed 0, 2, 4, 6, 8, 10 hours or 3 days after the first treatment. Control rats from the same litter were treated in the same way but received only the vehicle. In order to complete the study of the naturally occurring maturation, another group of rats was killed when they were 12, 13, 15, 16, 17, 18, 19, 20, 21 or 30 days old. Animal and intestine weights were measured. Disaccharidase specific activity, and protein, DNA and RNA contents were estimated in the small intestine. Histological and ultrastructural aspects of the intestinal mucosa were examined. For all these parameters, the maturation induced by spermine ingestion appeared close to that occurring naturally at weaning. Consequently, dietary spermine induces all the morphological and biochemical modifications characterizing the intestinal postnatal maturation in the suckling rat suggesting a role of the polyamines in the naturally occurring processes.

Role of interleukin-1 beta, interleukin-6, and TNF-alpha in intestinal maturation induced by dietary spermine in rats

In the present investigation, the authors aimed to evaluate the role of cytokines in intestinal postnatal maturation induced by dietary polyamines. Neonatal rats were administered either saline (8 mumol) orally. Spermine increased interleukin-1 beta (IL-1 beta), IL-6, and TNF-alpha plasma concentration. The maximum concentrations of IL-1 beta, IL-6, and TNF-alpha were, respectively, observed at 4, 4, and 8 h posttreatment. Intraperitoneal (i.p.) injection of IL-1 beta increased the specific activity of sucrase in whole small intestine, whereas the specific activities of maltase and lactase were significantly enhanced only in the jejunum. IL-6 elicited sucrase and increased maltase specific activity in the whole small intestine, but lactase specific activity was not affected. TNF-alpha had no effect on sucrase and maltase specific activity, but a slight augmentation of lactase specific activity was detected in the jejunum. Spermine and spermidine content in the intestine was increased by i.p. injection of IL-1 beta and IL-6. Corticosterone secretion was elevated by single i.p. injection of IL-1 beta, IL-6, or TNF-alpha. These findings suggest that spermine could induce postnatal intestinal development and corticosterone secretion through a cytokine-dependent mechanism.