The αMSH-Dependent PI3K Pathway Supports Energy Metabolism, via Glucose Uptake, in Melanoma Cells

Stimulation of melanocytes and murine melanoma cells with αMSH plus the PI3K inhibitor LY294002 resulted in ROS increase, oxidative DNA damage, and pigment retention. We performed cellular and molecular biology assays (Western blot, FACS, immunofluorescence analysis, scratch assay) on murine and human melanoma cells. Treatment with αMSH plus LY294002 altered cortical actin architecture. Given that cytoskeleton integrity requires energy, we next evaluated ATP levels and we observed a drop in ATP after exposure to αMSH plus LY294002. To evaluate if the αMSH-activated PI3K pathway could modulate energy metabolism, we focused on glucose uptake by analyzing the expression of the Glut-1 glucose translocator. Compared with cells treated with αMSH alone, those exposed to combined treatment showed a reduction of Glut-1 on the plasma membrane. This metabolic alteration was associated with changes in mitochondrial mass. A significant decrease of the cell migratory potential was also observed. We demonstrated that the αMSH-dependent PI3K pathway acts as a regulator of energy metabolism via glucose uptake, influencing the actin cytoskeleton, which is involved in melanosome release and cell motility. Hence, these results could constitute the basis for innovative therapeutical strategies.

The α-melanocyte-stimulating hormone/melanocortin-1 receptor interaction: A driver of pleiotropic effects beyond pigmentation

Melanocortin-1 Receptor (MC1R), when stimulated by alpha-melanocyte-stimulating hormone (α-MSH), is a driver of eumelanogenesis. Brown/black eumelanin is an effective filter against ultraviolet radiation (UVR) and is a scavenger of free radicals. Several polymorphic variants of MC1R are frequent in red-head people. These polymorphisms reduce the ability of MC1R to promote eumelanogenesis after its activation and spontaneous pheomelanogenesis take place. Since pheomelanin can act as an endogenous photosensitizer, people carrying MC1R polymorphisms are more susceptible to skin cancer. Here, we summarize current knowledge on the biology of MC1R beyond its ability to drive eumelanogenesis. We analyze its capacity to cope with oxidative insult and consequent DNA damage. We describe its ability to transduce through different pathways. We start from the canonical pathway, the cAMP/protein kinase A (PKA) pathway mainly involved in promoting eumelanogenesis, and protection from oxidative damage, and we then move on to describe more recent knowledge concerning ERK pathways, phosphoinositide 3-kinase (PI3K) pathway/AKT, and α-MSH/Peroxisome proliferators activated receptor-γ (PPAR-γ) connection. We describe MC1R polymorphic variants associated with melanoma risk which represent an open window of clinical relevance.

The PI3K pathway induced by αMSH exerts a negative feedback on melanogenesis and contributes to the release of pigment

The melanocortin-1 receptor (MC1R) belongs to the family of the G protein-coupled receptor (GPCR). Activated GPCRs can promote the phosphoinositide 3-kinase (PI3K) pathway. Few studies deal with the role of the PI3K pathway activation in response to αMSH. On B16-F10 cell line, we investigated the αMSH-dependent modulation of pAKT/AKT, as a key element of the PI3K pathway after rapid and prolonged stimulation. We demonstrated that αMSH triggers a rapid modulation of AKT which culminates in an increase in its phosphorylation. We highlighted a comparable upregulation of pAKT after exposure to αMSH on primary cultures of normal human melanocytes (NHMs) expressing a wild-type MC1R. On B16-F10 cells, NHMs, and an ex vivo model of human skin biopsies, we explored the influence of PI3K/AKT signaling triggered by αMSH, focusing on the control of melanogenesis and pigment release. We showed that the αMSH-dependent PI3K/AKT pathway exerts a negative feedback on melanogenesis and promotes the extracellular release of pigment. We strengthened the role of the PI3K/AKT pathway triggered by αMSH in preserving redox equilibrium and genome integrity, highlighting its role in affecting cell survival.

Bovine colostrum induces the differentiation of human primary keratinocytes

Bovine colostrum, the first milk secreted by the mammary glands of cows shortly after they have given birth, provides a natural source of bioactive substances helpful to promote tissue development and repair, and to maintain a healthy immune system. Owing to its properties, the use of colostrum in the treatment of human diseases is under investigation. We evaluated the biological activity of colostrum on human primary keratinocytes, focusing on its effects with regard to a proliferation/differentiation balance. Using cellular and molecular approaches, we showed that colostrum favors a cell cycle withdrawal by increasing the expression of p21/WAF1 and p27/KIP1. It also promotes the transition of keratinocytes from a proliferating to a differentiating state, as assessed by a decrease in keratin 5 and an increase in keratin 16. We demonstrated the ability of colostrum to induce the expression of early and late differentiation markers (keratin 1, involucrin, and filaggrin) and the synthesis of caspase 14 and bleomycin hydrolase, the two main enzymes involved in filaggrin maturation. Moreover, we showed that bovine colostrum is able to promote keratinocyte stratification and terminal differentiation not only in two-dimensional (2D), but also in a more physiological system of three-dimensional (3D) skin equivalents. Finally, we demonstrated that colostrum stimulates cell differentiation through the PI3K/PLC-γ1/PKCα pathways mainly associated to tyrosine kinase receptors. These results suggest the possibility to benefit from colostrum properties for the treatment of skin diseases characterized by altered differentiation and perturbed barrier function.

Cerium Oxide Nanoparticles Re-establish Cell Integrity Checkpoints and Apoptosis Competence in Irradiated HaCat Cells via Novel Redox-Independent Activity

Cerium oxide nanoparticles (CNPs) are potent radical scavengers protecting cells from oxidative insults, including ionizing radiation. Here we show that CNPs prevent X-ray-induced oxidative imbalance reducing DNA breaks on HaCat keratinocytes, nearly abating mutagenesis. At the same time, and in spite of the reduced damage, CNPs strengthen radiation-induced cell cycle arrest and apoptosis outcome, dropping colony formation; notably, CNPs do not possess any intrinsic toxicity toward non-irradiated HaCat, indicating that they act on damaged cells. Thus CNPs, while exerting their antioxidant action, also reinforce the stringency of damage-induced cell integrity checkpoints, promoting elimination of the “tolerant” cells, being in fact radio-sensitizers. These two contrasting pathways are mediated by different activities of CNPs: indeed Sm-doped CNPs, which lack the Ce³⁺/Ce⁴⁺ redox switch and the correlated antioxidant action, fail to decrease radiation-induced superoxide formation, as expected, but surprisingly maintain the radio-sensitizing ability and the dramatic decrease of mutagenesis. The latter is thus attributable to elimination of damaged cells rather than decreased oxidative damage. This highlights a novel redox-independent activity of CNPs, allowing selectively eliminating heavily damaged cells through non-toxic mechanisms, rather reactivating endogenous anticancer pathways in transformed cells.

The α-melanocyte stimulating hormone/peroxisome proliferator activated receptor-γ pathway down-regulates proliferation in melanoma cell lines

Background

The α-Melanocyte Stimulating Hormone (αMSH)/Melanocortin-1 receptor (MC1R) interaction promotes melanogenesis through the cAMP/PKA pathway. The direct induction of this pathway by Forskolin (FSK) is also known to enhance melanocyte proliferation. αMSH acts as a mitogenic agent in melanocytes and its effect on proliferation of melanoma cells is less known. We previously identified the αMSH/Peroxisome Proliferator Activated Receptor (PPARγ) pathway as a new pathway on the B16-F10 mouse melanoma cell line. αMSH induced the translocation of PPARγ into the nucleus as an active transcription factor. This effect was independent of the cAMP/PKA pathway and was mediated by the activation of the PI(4,5)P2/PLC pathway, a pathway which we have described to be triggered by the αMSH-dependent MC1R stimulation. Moreover, in the same study, preliminary experiments showed that mouse melanoma cells responded to αMSH by reducing proliferation and that PPARγ was involved in this effect. Due to its key role in the control of cell proliferation, PPARγ agonists are used in therapeutic models for different forms of cancer, including melanoma. The purpose of this study was: (a) to confirm the different proliferative behavior in response to αMSH in healthy and in melanoma condition; (b) to verify whether the cAMP/PKA pathway and the PLC/PPARγ pathway could exert an antagonistic function in the control of proliferation; (c) to deepen the knowledge of the molecular basis responsible for the down-proliferative response of melanoma cells after exposure to αMSH.

Methods

We employed B16-F10 cell line, a human melanoma cell line (Mel 13) and two primary cultures of human melanocytes (NHM 1 and NHM 2, respectively), all expressing a wild type MC1R and responding to the αMSH in terms of pigmentation. We evaluated cell proliferation through: a) cell counting, b) cell cycle analysis c) protein expression of proliferation modulators (p27, p21, cyclin D1 and cyclin E).

Results

The αMSH acted as a mitogenic agent in primary cultures of human melanocytes, whereas it determined a slow down of proliferation in melanoma cell lines. FSK, as an inducer of the cAMP/PKA pathway, reproduced the αMSH mediated effect on proliferation in NHMs but it did not mimic the αMSH effect on proliferation in B16-F10 and Mel 13 melanoma cell lines. Meanwhile, 3 M3-FBS (3 M3), as an inducer of PI(4,5)P2/PLC pathway, reproduced the αMSH proliferative effect. Further experiments, treating melanoma cell lines with αMSH in the presence/absence of GW9662, as an inhibitor of PPARγ, confirmed the key role of this transcription factor in decreasing cell proliferation in response to the hormone exposure.

Conclusions

In both melanoma cell lines, αMSH determined the reduction of proliferation through the PI(4,5)P2/PLC pathway, employing PPARγ as an effector element. These evidence could offer perspectives for new therapeutic approaches for melanoma.

Electronic supplementary material

The online version of this article (10.1186/s13046-017-0611-4) contains supplementary material, which is available to authorized users.

The activation of PPARγ by 2,4,6-Octatrienoic acid protects human keratinocytes from UVR-induced damages

Increasing attention is addressed to identify products able to enhance skin photoprotection and to prevent skin carcinogenesis. Several studies have demonstrated that the α-melanocyte stimulating hormone (αMSH), acting on a functional MC1R, provides a photoprotective effect by inducing pigmentation, antioxidants and DNA repair. We discovered a link between αMSH and the nuclear receptor Peroxisome Proliferator-Activated Receptor-γ (PPARγ), suggesting that some of the αMSH protective effects may be dependent on PPARγ transcriptional activity. Moreover, we demonstrated that the activation of PPARγ by the parrodiene 2,4,6-octatrienoic acid (Octa) induces melanogenesis and antioxidant defence in human melanocytes and counteracts senescence-like phenotype in human fibroblasts. In this study, we demonstrate that the activation of PPARγ by Octa exerts a protective effect against UVA- and UVB-induced damage on normal human keratinocytes (NHKs), the major target cells of UV radiation. Octa promotes the antioxidant defence, augments DNA repair and reduces the induction of proteins involved in UV-induced DNA damage response. Our results contribute to deepen the analysis of the αMSH/PPARγ connection and suggest perspectives for the development of new molecules and formulations able to prevent cutaneous UV damage by acting on the different skin cell populations through PPARγ activation.

Tramesan, a novel polysaccharide from Trametes versicolor. Structural characterization and biological effects

Mushrooms represent a formidable source of bioactive compounds. Some of these may be considered as biological response modifiers; these include compounds with a specific biological function: antibiotics (e.g. plectasin), immune system stimulator (e,g, lentinan), antitumor agents (e.g. krestin, PSK) and hypolipidemic agents (e.g. lovastatin) inter alia. In this study, we focused on the Chinese medicinal mushroom "yun zhi", Trametes versicolor, traditionally used for (cit.) "replenish essence and qi (vital energy)". Previous studies indicated the potential activity of extracts from culture filtrate of asexual mycelia of T. versicolor in controlling the growth and secondary metabolism (e.g. mycotoxins) of plant pathogenic fungi. The quest of active principles produced by T. versicolor, allowed us characterising an exo-polysaccharide released in its culture filtrate and naming it Tramesan. Herein we evaluate the biological activity of Tramesan in different organisms: plants, mammals and plant pathogenic fungi. We suggest that the bioactivity of Tramesan relies mostly on its ability to act as pro antioxidant molecule regardless the biological system on which it was applied.

Linking αMSH with PPARγ in B16-F10 melanoma

We have discovered a new α-melanocyte stimulating hormone (α-MSH)/peroxisome proliferator activated receptor-γ (PPAR-γ) connection in B16-F10 cells. Both PPAR-γ up-regulation and its induction as an active transcription factor were observed in response to α-MSH. The α-MSH/PPAR-γ connection influenced both pigmentation and proliferation. The forskolin-stimulated cAMP/PKA pathway was not able to induce either PPAR-γ translocation into the nucleus or PPAR-γ transcriptional activity. As the melanocortin-1 receptor, the specific receptor for the α-MSH, is a G-protein coupled receptor, we wondered whether the phosphatidylinositol [PI(4,5)P(2) /PLC(β) ] signal pathway was involved in mediating the α-MSH-dependent PPAR-γ activation. Employing inhibitors of PI(4,5)P(2) /PLC(β) pathway, the results of our experiments suggested that this pathway was promoted by α-MSH and that α-MSH played a role in mediating PPAR-γ activation. We have demonstrated, for the first time, that α-MSH induces the PI(4,5)P(2) /PLC(β) pathway, through analysis of the basic steps of the pathway. The α-MSH effect on PPAR-γ was independent of animal species and was not correlated with the physio-pathological status.

Proinflammatory cytokine production in HaCaT cells treated by eosin: implications for the topical treatment of psoriasis

Psoriasis is a multifactorial skin dermatosis characterized in its classical form by erythematous and hyperkeratotic plaques on extensor surfaces of the body, that in most cases can be managed therapeutically by topical agents. Hyperproliferation and a marked inflammation in both epidermis and dermis are thought to be driven by interaction of activated type-1 T lymphocytes and antigen-presenting cells and keratinocytes that release several proinflammatory and immunomodulating molecules. The aim of this study is to investigate whether tetrabromofluorecin, commonly know as eosin, a classical compound traditionally topically used in psoriasis for its presumed anti-inflammatory activities, is able to modulate the production of TNF-alpha, IL-6 and IL-8 that are recognized as the most active and characterized cytokines in the pathogenesis of this skin disorder. HaCaT cell line was used to verify the effects on epidermal inflammation by eosin at scalar doses after testing the viability of cells. Two different population of cells, one stimulated by IFNgamma and one non-stimulated, were cultivated in presence of tolerable concentrations. The expression and release of IL-6, IL-8, IL-10, and TNF-alpha were analysed by RT-PCR and ELISA, respectively. Our results show that tolerable concentrations of eosin were 0.05%, 0.02%, and 0.01%. The expression and production of TNFalpha, IL-8 and IL-6 were dramatically reduced in presence of eosin 0.05% and 0.02% and the action of eosin was more pronounced on TNF-alpha. In agreement with clinical data, our results show that in presence of tolerable concentrations, eosin seems to influence remarkably the production of three important cytokines involved in the hyperproliferation and inflammatory process, giving a specific explanation of its efficacy and supporting its topical use in the clinical setting.

MC1R stimulation by alpha-MSH induces catalase and promotes its re-distribution to the cell periphery and dendrites

We demonstrated a direct correlation between melanogenic and catalase activities on in vitro and ex vivo models. Here, we investigated whether the stimulation of Melanocortin-1 Receptor (MC1R) could influence catalase expression, activity and cellular localization. For this purpose, we treated B16-F0 melanoma cells with alpha-Melanocyte Stimulating Hormone (alpha-MSH) and we showed a rapid induction of catalase through a cAMP/PKA-dependent, microphthalmia-associated transcription factor (MITF) independent mechanism, acting at post-transcriptional level. Moreover, alpha-MSH promoted a partial re-distribution of catalase to the cell periphery and dendrites. This work strengthens the correlation between melanogenesis and anti-oxidants, demonstrating the induction of catalase in response to a melanogenic stimulation, such as alpha-MSH-dependent MC1R activation. Moreover, this study highlights catalase regulatory mechanisms poorly known, and attributes to alpha-MSH a protective role in defending melanocytes, and possibly keratinocytes, not only on the basis of its pigmentary action, but also for its capacity to stimulate a quick anti-oxidant defence.

p38 regulates pigmentation via proteasomal degradation of tyrosinase

The synthesis of melanin pigments, or melanogenesis, is regulated by the balance of a variety of signal transduction pathways. Among these pathways, p38 MAPK signaling was found to be involved in stress-induced melanogenesis and to be activated by alpha-melanocyte-stimulating hormone (alpha-MSH) and ultraviolet irradiation. Previous studies have shown that alpha-MSH-stimulated melanogenesis can be inhibited by blocking p38 MAPK activity with SB203580, a pyridinyl imidazole compound. Consistent with this, we observed that pyridinyl imidazoles (SB203580 and SB202190) inhibited both basal and alpha-MSH-induced melanogenesis in B16 melanoma cells. However, SB202474, which has no ability to inhibit p38 MAPK activity and is usually used as a negative control compound in p38 MAPK studies, also suppressed melanin synthesis induction. Furthermore, the independence of the p38 kinase pathway from the repression of melanogenesis by pyridinyl imidazole compounds was also confirmed by small interfering RNA experiments. Interfering with p38 MAPK expression surprisingly stimulated melanogenesis and tyrosinase family protein expression. Although the molecular mechanism(s) by which p38 promotes the degradation of melanogenic enzymes remain to be determined, the involvement of the ubiquitin-proteasome pathway was demonstrated by co-treatment with the proteasome-specific inhibitor MG132 and the relative decrease in the ubiquitination of tyrosinase in cells transfected with p38-specific small interfering RNA.

Human papillomavirus-16 E7 interacts with glutathione S-transferase P1 and enhances its role in cell survival

Background

Human Papillomavirus (HPV)-16 is a paradigm for “high-risk” HPVs, the causative agents of virtually all cervical carcinomas. HPV E6 and E7 viral genes are usually expressed in these tumors, suggesting key roles for their gene products, the E6 and E7 oncoproteins, in inducing malignant transformation.

Methodology/Principal Findings

By protein-protein interaction analysis, using mass spectrometry, we identified glutathione S-transferase P1-1 (GSTP1) as a novel cellular partner of the HPV-16 E7 oncoprotein. Following mapping of the region in the HPV-16 E7 sequence that is involved in the interaction, we generated a three-dimensional molecular model of the complex between HPV-16 E7 and GSTP1, and used this to engineer a mutant molecule of HPV-16 E7 with strongly reduced affinity for GSTP1.When expressed in HaCaT human keratinocytes, HPV-16 E7 modified the equilibrium between the oxidized and reduced forms of GSTP1, thereby inhibiting JNK phosphorylation and its ability to induce apoptosis. Using GSTP1-deficient MCF-7 cancer cells and siRNA interference targeting GSTP1 in HaCaT keratinocytes expressing either wild-type or mutant HPV-16 E7, we uncovered a pivotal role for GSTP1 in the pro-survival program elicited by its binding with HPV-16 E7.

Conclusions/Significance

This study provides further evidence of the transforming abilities of this oncoprotein, setting the groundwork for devising unique molecular tools that can both interfere with the interaction between HPV-16 E7 and GSTP1 and minimize the survival of HPV-16 E7-expressing cancer cells.

Multiple mechanisms for hydrogen peroxide-induced apoptosis

The mechanisms of cell killing by oxidative stress, in particular by hydrogen peroxide, are not yet well clarified. Here, we show that during recovery after H(2)O(2) treatment, apoptosis occurs in two different waves, peaking at 8 h (early) and 18 h (late) of recovery from oxidative stress. The two peaks are differentially modulated by a set of inhibitors of metabolic processes, which suggests that the first peak depends on DNA break formation, whereas the second may be correlated with H(2)O(2)-induced mitochondrial alterations.

Correlation between melanogenic and catalase activity in in vitro human melanocytes: a synergic strategy against oxidative stress

UV-induced DNA damage can lead to melanoma, the most dangerous form of skin cancer. Understanding the mechanisms employed by melanocytes to protect against UV is therefore a key issue. In melanocytes, catalase is the main enzyme responsible for degrading hydrogen peroxide and we have previously shown that that low basal levels of catalase activity are associated with the light phototype in in vitro and ex vivo models. Here we investigate the possible correlation between its activity and melanogenesis in primary cultures of human melanocytes. We show that while the total melanin concentration is directly correlated to the level of pigmentation, the more the degree of pigmentation increased, the lower the proportion of pheomelanin present. Moreover, in human melanocytes in vitro, catalase-specific mRNA, protein and enzymatic activity were all directly correlated with total cellular melanin content. We also observed that immediately after a peroxidative treatment, the increase in reactive oxygen species was inversely associated with pigmentation level. Darkly pigmented melanocytes therefore possess two protective strategies represented by melanins and catalase activity that are likely to act synergistically to counteract the deleterious effects of UV radiation. By contrast, lightly pigmented melanocytes possess lower levels of melanogenic and catalase activity and are therefore more susceptible to accumulate damage after UV exposition.

GSK3beta inhibition promotes melanogenesis in mouse B16 melanoma cells and normal human melanocytes

Glycogen synthase kinase 3beta (GSK3beta) is implicated in many biological events, including embryonic development, cell differentiation, apoptosis, and the insulin response. GSK3beta also plays a key role in the Wnt/beta-catenin pathway. The master regulator of the pigmentation microphthalmia-associated transcription factor (MITF) is a target for the Wnt pathway, however, to date, the regulatory role of GSK3beta in the control of melanogenesis has not been elucidated. In this study, we evaluated the effect of inhibiting GSK3beta activity on the regulation of melanocyte differentiation. Exposure of the murine melanoma cell line B16 and normal human melanocytes to GSK3beta specific inhibitors (SB216763, SB415286, BIO, and LiCl) resulted in a dose-dependent accumulation of beta-catenin. This is associated with the induction of melanocyte differentiation-associated markers such as melanin synthesis, tyrosinase activity, and expression of tyrosinase and the microphthalmia-associated transcription factor. Attenuation of GSK3beta activity has an inhibitory effect on cell growth, and this was accompanied by morphological changes. Moreover, treatment of B16 cells with a siRNA targeted against beta-catenin completely abolished the promelanogenic effect of GSK3beta inhibition, however, the overexpression of a constitutively active mutant form of beta-catenin (pCS2beta-cat-mut) only slightly increased the degree of pigmentation. These results demonstrated that GSK3beta is implicated in the regulation of melanogenesis and that pharmacological inhibition of its activity could increase melanin synthesis through mechanisms probably not restricted to Wnt/beta-catenin pathway activation.

New technologies used in the study of human melanoma

The amount of information on tumor biology has expanded enormously, essentially due to the completion of the human genome sequencing and to the application of new technologies that represent an exciting breakthrough in molecular analysis. Often these data spring from experimental procedures, such as a serial analysis of gene expression (SAGE) and DNA microarrays, which cannot be defined as hypothesis-driven: it may appear to be a "brute force" approach through which no information can be directly generated concerning the specific functions of selected genes in a definite context. However, interesting results are fruitfully generated, and thus it is important to consider the enormous potential these new technologies possess and to learn how to apply this novel form of knowledge in the emerging field of molecular medicine. This review, after a limited outline regarding several classic aspects of human cutaneous melanoma biology, genetics, and clinical approaches, will focus on the proficient use of up-to-date technologies in the study of the neoplastic disease and on their capability to provide effective support to conventional approaches in melanoma diagnosis, prognosis, and treatment.

Differential in vitro cellular response induced by exposure to synthetic vitreous fibers (SVFs) and asbestos crocidolite fibers

In this study, we analyzed the effects of synthetic vitreous fibers (SVFs) on a mesothelial (MeT5A) and a fibroblast cell line (NIH3T3), compared to those exerted by crocidolite asbestos fibers. SVFs (glass wool, rock wools) do not induce significant changes in cell mortality, whereas crocidolite asbestos fibers caused a dose-dependent cytotoxicity. We investigated the correlation between the fiber-induced cytotoxicity and the extent and type of interaction of the fibers with the cell surface, and we observed that SVFs, unlike crocidolite asbestos fibers, establish few and weak interactions. Moreover, after internalization, crocidolite asbestos fibers are often found free in the cytoplasm, whereas glass wool fibers are mainly localized inside cytoplasmic vacuoles. After treatments, we also detected signs of oxidative stress, revealed by an increased reactive oxygen species (ROS) production and by an induction of superoxide dismutase (SOD) activity. The lipoperoxidative damage was characterized by a decrease in polyunsaturated fatty acids (PUFA), an increase in the content of thiobarbituric reactive species (TBARS) and a consumption of vitamin E, as a lipophilic antioxidant. Furthermore, we investigated the effect of fiber exposure on cell proliferation. and it was found that, unlike crocidolite asbestos fibers, SVFs did not induce a significant increase in DNA synthesis.

UVA-induced modification of catalase charge properties in the epidermis is correlated with the skin phototype

The harmful effects of UVA radiation (320-400 nm) on the skin have been related to the generation of reactive oxygen species. Pheomelanin, the pigment characteristic of fair-skinned individuals, amplifies these effects. In vitro, in the presence of photosensitizing agents, UVA light produces singlet oxygen, which reacts with several targets. We have investigated a possible correlation between melanin-type and the antioxidant defense system after UV, focusing on the activities of superoxide dismutase and catalase, which correlated with the phototype of epidermal reconstructs. UVA was more effective than UVB in damaging these enzymatic activities, especially catalase. Furthermore, UVA irradiation induced a free-radical-mediated damage in the cells, leading to an oxidation of cell proteins. On catalase, synthetic pheomelanin amplified this effect on specific targets, such as residues of tryptophan and methionine. UVA irradiation of low phototype reconstructed epidermis and of U937 through synthetic pheomelanin induced a modification in the electrophoretic properties of native catalase, which was counteracted by histidine, a quencher of singlet oxygen. These results demonstrate that pheomelanin could act as a photosensitizing agent, following UVA irradiation, inducing charge modifications of native catalase, by a mechanism involving singlet oxygen or its downstream products.

Ferritin contributes to melanoma progression by modulating cell growth and sensitivity to oxidative stress

PURPOSE

Employing an in vitro model system of human melanoma progression, we previously reported ferritin light chain (L-ferritin) gene overexpression in the metastatic phenotype. Here, we attempted to characterize the role of ferritin in the biology of human melanoma and in the progression of this disease.

EXPERIMENTAL DESIGN

Starting from the LM human metastatic melanoma cell line, we engineered cell clones in which L-ferritin gene expression was down-regulated by the stable expression of a specific antisense construct. These cells were then assayed for their growth capabilities, chemoinvasive properties, and sensitivity to oxidative stress. Additionally, ferritin protein content in primary and metastatic human melanomas was determined by immunohistochemistry.

RESULTS

Artificial L-ferritin down-regulation in the LM cells strongly inhibited proliferation and chemoinvasion in vitro and cell growth in vivo. In addition, L-ferritin down-regulated cells displayed enhanced sensitivity to oxidative stress and to apoptosis. Concurrently, immunohistochemical analysis of a human melanoma tissue array revealed that ferritin expression level in metastatic lesions was significantly higher (P < 0.0001) than in primary melanomas. Furthermore, ferritin expression was constantly up-regulated in autologous lymph node melanoma metastases when compared with the respective primary tumors in a cohort of 11 patients.

CONCLUSIONS

These data suggest that high ferritin expression can enhance cell growth and improve resistance to oxidative stress in metastatic melanoma cells by interfering with their cellular antioxidant system. The potential significance of these findings deserves to be validated in a clinical setting.

Ferritin light chain down-modulation generates depigmentation in human metastatic melanoma cells by influencing tyrosinase maturation

Recently, after the identification of ferritin light chain (L-ferritin) gene and protein over-expression in human metastatic melanoma cells, we engineered, starting from the LM metastatic melanoma cell line, clones in which L-ferritin gene expression was down-regulated by the stable expression of a specific antisense construct. The present investigation started from the observation that L-ferritin down-regulated LM cells displayed a less pigmented phenotype, confirmed by a major decrease of total melanin, when compared to control LM cells. This finding was accompanied by a dramatic decrease in tyrosinase activity, which was not paralleled by a concomitant reduction of the amount of tyrosinase specific mRNA. Western blot analysis of tyrosinase in control LM cells displayed a pattern, which corresponds to the progressive glycosylation of the native protein up to the 80 kDa form, considered the functional one. Tyrosinase pattern assayed in L-ferritin down-regulated LM cells showed the remarkable absence of the 80 kDa form and a prevalence of endoglycosidase H (endo H)-sensitive immature (70 kDa) tyrosinase, accumulated in the endoplasmic reticulum (ER), as confirmed by confocal microscopy analysis. These results demonstrate that, in a human metastatic melanoma cell line, the stress condition promoted by L-ferritin down-modulation, can substantially influence proper maturation of tyrosinase.

UVB-induced activation and internalization of keratinocyte growth factor receptor

Ultraviolet irradiation of mammalian cells induces several events that include activation of growth factor receptors and triggering of signal transduction pathway. Most of the UV responses are mediated by the production of reactive oxygen species (ROS) and can be blocked by antioxidants. In this study, we analysed the effect of UVB irradiation at physiologic doses and that of the pro-oxidant agent cumene hydroperoxide (CUH) on the activation of the receptor for keratinocyte growth factor (KGF), a key mediator of epithelial growth and differentiation. Exposure to both UVB (30-150 mJ/cm(2)) and CUH (200 microM of NIH3T3 KGFR (KGF receptors) transfectants caused a rapid tyrosine phosphorylation and activation of KGFR similar to that induced by KGF, and internalization of the activated receptor. The KGFR expression appeared unmodified by the treatments. Ultrastructural observations of both UVB- and CUH-treated cells showed a normal morphology of the plasma membranes and intracellular organelles. The antioxidant N-acetylcysteine inhibited UVB-induced receptor phosphorylation. The generation of an intracellular oxidative stress was detected as a decrease of catalase activity and of vitamin E, and reduced glutathione levels, whereas superoxide dismutase activity was not significantly modified. A peroxidation of polyunsaturated fatty acids of cell membranes was observed after both treatments, associated with the intracellular oxidative stress. Similar biochemical events were observed on NIH3T3 untransfected control cells, suggesting that KGFR activation follows intracellular generation of ROS and is not associated with a scavenging effect. Taken together our results demonstrate that exposure to UVB and to oxidant stimuli induces a rapid intracellular production of ROS, which in turn are capable of triggering KGFR activation and internalization, similar to those induced by KGF.

Alpha-tocopherol protects against cisplatin-induced toxicity without interfering with antitumor efficacy

Our aim was 2-fold: to investigate the role of alpha-tocopherol supplementation on the antitumor activity of DDP and to evaluate the effect of alpha-tocopherol on the survival and neurotoxicity of DDP-treated mice. Experiments performed on the M14 human melanoma line demonstrated that alpha-tocopherol supplementation did not influence the efficacy of DDP; the inhibition of cell survival and of the in vivo tumor growth after treatment with alpha-tocopherol and DDP combination was similar to that observed after DDP alone. Conversely, alpha-tocopherol was also able to increase survival of mice treated with a high dose of DDP. While DDP alone produced death in about 70% of mice, the combination reduced deaths to about 30%. Analysis of oxidative stress markers and peroxidative damage in organs indicated that the protective effect of alpha-tocopherol was mainly related to its antioxidant activity. A significant increase in the concentration of TBARS and decreased PUFAs and catalase activity were observed after DDP treatment, while with alpha-tocopherol the levels of these markers were comparable to those observed in untreated mice. Histologic analysis performed on peripheral nerve revealed that alpha-tocopherol also protected mice from severe neurologic damage induced by DDP treatment. In conclusion, our results demonstrate that alpha-tocopherol protects against the systemic toxicity and neurotoxicity induced by DDP without interfering with its antitumor activity and suggest that this combination is a promising strategy to improve the therapeutic index of DDP-based chemotherapy.

Neuroprotective effect of vitamin E supplementation in patients treated with cisplatin chemotherapy

PURPOSE

The aim of this study is to evaluate the neuroprotective effect of antioxidant supplementation with vitamin E in patients treated with cisplatin chemotherapy.

METHODS

Between April 1999 and October 2000, forty-seven patients were randomly assigned to either group one, which received vitamin E supplementation during cisplatin chemotherapy, or to group two, which received cisplatin chemotherapy alone. Alpha-tocopherol (vitamin E; 300 mg/d) was administered orally before cisplatin chemotherapy and continued for 3 months after the suspension of treatment. For preclinical studies, nude mice carrying the human melanoma tumor were treated with cisplatin alone or in combination with vitamin E.

RESULTS

Twenty-seven patients completed six cycles of cisplatin chemotherapy: 13 patients in group one and 14 patients in group two. The incidence of neurotoxicity was significantly lower in group one (30.7%) than it was in group two (85.7%; P <.01). The severity of neurotoxicity, measured with a comprehensive neurotoxicity score based on clinical and neurophysiological parameters, was significantly lower in patients who were supplemented with vitamin E than in patients who were not supplemented with vitamin E (2 v 4.7, P <.01). The results of the preclinical studies showed that when cisplatin was combined with vitamin E, no differences were observed in tumor weight inhibition, tumor growth delay, or life span as compared with treatment with cisplatin alone.

CONCLUSION

Supplementation of patients receiving cisplatin chemotherapy with vitamin E decreases the incidence and severity of peripheral neurotoxicity.

Polyunsaturated fatty acids of germ cell membranes, glutathione and blutathione-dependent enzyme-PHGPx: from basic to clinic

The lipid metabolism in sperm cells is important both for energy production and for cell structure. A special composition of membrane phospholipids, rich in polyunsaturated fatty acids (PUFA), and the different composition of sperm and immature germ cell membrane are described and discussed. Testis germ cells as well as epididymal maturing spermatozoa are endowed with enzymatic and non-enzymatic scavenger systems to prevent lipoperoxidative damage. Catalase, superoxide dismutase, and glutathione-dependent oxidoreductases are present in variable amounts in the different developmental stages. Phospholipid hydroperoxide glutathione peroxidase (PHGPx) activity and roles in caput and cauda epididymal sperm cells are discussed. Also seminal plasma has a highly specialized scavenger system that defends the sperm membrane against lipoperoxidation and the degree of PUFA insaturation acts to achieve the same goal. Systemic predisposition and a number of pathologies can lead to an anti-oxidant/pro-oxidant disequilibrium. Scavengers, such as glutathione can be used to treat these cases as they can restore the physiological constitution of PUFA in the cell membrane.

Mitochondrial impairment in peripheral blood mononuclear cells during the active phase of vitiligo

Several hypotheses have been made about the pathogenesis of vitiligo, and some of them have considered a systemic involvement in the course of the disease. Evidence has been presented on the role of oxidative stress as the initial event in melanocyte degeneration. In accordance with this view, we determined the levels of some antioxidants, i.e., superoxide dismutase, catalase, reduced glutathione, and vitamin E, in erythrocytes and/or peripheral blood mononuclear cells from patients with active or stable vitiligo and from a control group of healthy subjects. In erythrocytes the parameters evaluated were not significantly different. On the contrary, in peripheral blood mononuclear cells, superoxide dismutase activity was increased in both groups of patients, whereas catalase activity, reduced glutathione and vitamin E levels were decreased exclusively in subjects with active disease. The imbalance of antioxidants was associated with hyperproduction of reactive oxygen species due to a mitochondrial impairment as cyclosporin A, an inhibitor of the permeability transition pores opening, significantly reduced the reactive oxygen species production. Moreover an alteration of the mitochondrial transmembrane potential and a higher percentage of apoptotic cells were observed in active vitiligo patients. Based on these results, we suggest that, in vitiligo, mitochondria might be the target of different stimuli, such as reactive oxygen species generation, cytokines production, catecholamine release, alteration of Ca2+ metabolism, all of which capable of inducing melanocyte degeneration.

A pilot study on the relation between cisplatin neuropathy and vitamin E

Peripheral sensory neuropathy is the main non-hematological side-effect related to cisplatin chemotherapy. The strong similarity between clinical and neuropathological aspects in peripheral neuropathy induced by cisplatin and neurologic syndromes due to vitamin E deficiency, prompted us to investigate the relationship between cisplatin neuropathy and plasmatic level of vitamin E (alpha-tocopherol). We measured vitamin E in the plasma of 5 patients (Group 1) which developed severe neurotoxicity after cisplatin treatment and in another group of 5 patients (Group 2) we analyzed the plasmatic level of vitamin E before and after 2 or 4 cycles of cisplatin treatment. The results showed that the patients of group 1 presented low plasmatic levels of vitamin E and that the patients of group 2 presented significantly lower levels of vitamin E after 2 or 4 cycles of cisplatin than before treatment. Our preliminary data suggest that an inadequate amount of the antioxidant vitamin E due to cisplatin treatment could be responsible of the peripheral nerve damage induced by free-radicals. Given the lack of toxicity of vitamin E, we need to systematically assess the possible neuroprotective role of vitamin E supplementation in patients treated with cisplatin chemotherapy.

Fatty acid composition of spermatozoa and immature germ cells

A great deal of attention has recently been given to the essential role of polyunsaturated fatty acids (PUFA) of sperm membranes. We studied the fatty acid composition of the immature germ cells (IGC) and of the sperm populations separated by Percoll gradient in the ejaculate of normozoospermic patients. Fatty acid pattern was analysed by combined gas chromatography-mass spectrometry on a capillary column. In IGC, differences were found compared with mature spermatozoa, with a higher percentage of saturated fatty acids and of essential fatty acids. On the contrary, the long-chain PUFA were significantly lower in IGC. The highest concentration of n3 PUFA docohexaenoic acid (DHA) was detected in the spermatozoa deriving from 70-100% Percoll layers and a direct linear correlation was found between the increase of DHA and increased percentage of Percoll gradient. An inverse relationship between the percentage of atypical sperm forms in each layer and the percentage of DHA was also observed. This study demonstrates that the human germ cell line can elongate and desaturate essential fatty acids and that the percentage of long-chain PUFA is correlated with the normal morphology of sperm cells.

Antioxidant pattern in uveal melanocytes and melanoma cell cultures

PURPOSE

To investigate the antioxidant status of cultured uveal melanocytes from patients with uveal melanoma and uveal melanoma cells to characterize some of the biochemical properties of these cells in respect to the normal cutaneous melanocytes.

METHODS

The fatty acid pattern of membrane phospholipids, intracellular vitamin E level, and superoxide dismutase (SOD) and catalase activities were studied in uveal melanocytes (n = 10) and uveal melanoma cell (n = 10) cultures, by gas chromatography mass spectrometry or by spectrophotometer.

RESULTS

Among the uveal melanocyte cultures, two groups were differentiated, according to catalase activity: group A with catalase values comparable to those of cutaneous ones and higher SOD activity and group B with catalase values 2 SD lower (P<0.001) and lower SOD activity. Vitamin E concentration was not significantly different between melanoma cells and melanocytes, whereas a significantly higher percentage of polyunsaturated fatty acids was found in melanoma cells and the B group of melanocytes (P = 0.022). In uveal melanoma cells SOD activity was significantly lower than that detected in uveal melanocytes (P< 0.005).

CONCLUSIONS

These results show a different pattern of antioxidants in uveal melanocytes with respect to cutaneous ones, possibly related to the anatomic distribution. However, as in cutaneous melanocytes, two subgroups were identified on the basis of the antioxidant pattern that could be the expression of a constitutional increased susceptibility to oxidative stress in some subjects. Moreover, an imbalance of the antioxidants was observed in melanoma cells, possibly related to the disease status and progression.

The reconstructed epidermis with melanocytes: a new tool to study pigmentation and photoprotection

The reconstruction of the epidermal melanin unit ex vivo has been achieved during the last decade, using the combination of previous cell culture techniques. The system reviewed is basically a modification of the Pruniéras model, using the air-liquid interface to grow differentiated keratinocytes, with the addition of 5% melanocytes in the seeding suspension, as well as the use of a more adapted culture medium. Repeated UVB irradiation induces a stimulation of melanogenesis macroscopically, and increases melanin concentration and melanosome transfer in reconstructs. These results have been reproduced with skin of various phototypes. This model allows to study the physiology of the epidermal melanin unit as well as pathologic conditions, like vitiligo and nevi. Recent evidence of a complex interaction of keratinocytes and melanocytes in photoprotection was provided by the use of chimeric reconstructs and by comparing autologous reconstructs made with and without low phototype caucasoid melanocytes. Based on these findings, we suggest a novel interpretation of the concept of phototype.

Chimeric human epidermal reconstructs to study the role of melanocytes and keratinocytes in pigmentation and photoprotection

Chimeric epidermal reconstructs made with Negroid melanocytes and Caucasoid keratinocytes (or vice versa) were studied before and after UVB irradiation to understand the respective roles of these cells in tanning and photoprotection, especially lipoperoxidation and enzymatic defences against free radicals. Using this approach, we have confirmed overall the theory of the epidermal melanin unit. We have also shown that melanocytes of poorly tanning Caucasoids, which have a comparatively higher content of unsaturated fatty acids in their cell membrane, are more prone to the peroxidative effects of UV light, and that keratinocytes participate in photoprotection via phototype-dependent antioxidant enzyme activities, especially for catalase.

Increased sensitivity to peroxidizing agents is correlated with an imbalance of antioxidants in normal melanocytes from melanoma patients

We have previously shown an imbalance of the antioxidant system in some cultures of normal melanocytes from patients with melanoma. In order to evaluate if the alteration of the antioxidants could be the basis of an increased sensitivity to exposure to peroxidative agents, in cultured melanocytes from normal individuals (n = 11) and from patients with melanoma (n = 11), superoxide dismutase and catalase activities were evaluated by spectrophotometer, and the levels of vitamin E and of the polyunsaturated fatty acid of cell membranes were determined by gas chromatography mass spectrometry. In 5 out of the 11 cultures of melanocytes from melanoma patients, with respect to those from normal individuals, a significant decrease of catalase activity (Cat) associated with an increase of vitamin E (Vit E) concentration was found, whereas no significant modification of superoxide dismutase activity (SOD) was observed. A wide range of variability was detected in the percentage of the polyunsaturated fatty acids of the cell membranes and a correlation was found between the ratio SOD/Cat and the percentage of linoleic acid, indicating that the imbalance of the enzymatic antioxidants leads to a lipoperoxidative process. The electron microscopic examination of these cultures revealed many microvilli in the plasma membranes and nuclear infoldings and in the cytoplasm light vacuoles. Moreover some cells contained several dense bodies with a round shape and numerous spherical lamellae possibly representing immature melanosomes. Treatment with cumene hydroperoxide between 0.66 and 20 microM did not produce a significant modification of cell viability in melanocytes from normal individuals. On the contrary in melanocytes from melanoma patients correlated with the ratio Vit E/Cat, considered as a parameter of the antioxidant imbalance, a stimulatory effect was observed at 0.66 microM CUH and a cytotoxic effect at 20 microM. In conclusion our results suggest that a constitutional alteration of the scavenger system could be present in normal melanocytes from melanoma patients and that this could be the basis for an increased sensitivity to pro-oxidant agents.

Increased sensitivity to peroxidative agents as a possible pathogenic factor of melanocyte damage in vitiligo

To examine the sensitivity of vitiligo melanocytes to external oxidative stress, we studied enzymatic and non-enzymatic anti-oxidants in cultured melanocytes of normal subjects (n = 20) and melanocytes from apparently normal skin of vitiligo patients (n = 10). The activity of superoxide dismutase and catalase and the intracellular concentrations of vitamin E and ubiquinone were evaluated in cultures at the fourth or fifth passage. In addition, cells were exposed to various concentrations of a peroxidizing agent, cumene hydroperoxide (CUH, 0.66-20 microM), for 1 and 24 h. Compared to normal melanocytes, vitiligo melanocytes showed normal superoxide dismutase and significantly lower catalase activities and higher vitamin E and lower ubiquinone levels. At the concentration used, CUH did not significantly affect cell number or viability of melanocytes after either period of culture. On the contrary, vitiligo melanocytes were susceptible to the toxic effect of CUH after 24 h of continuous treatment at concentrations greater than 6.6 microM. The degree of CUH toxicity correlated strictly with the anti-oxidant pattern, defined as the ratio between vitamin E concentration and catalase activity, suggesting that the alteration in the antioxidants was the basis for sensitivity to the external oxidative stress. Our results demonstrate the presence of an imbalance in the anti-oxidant system in vitiligo melanocytes and provide further support for a free radical-mediated damage as an initial pathogenic event in melanocyte degeneration in vitiligo.

Protease inhibitors block apoptosis at intermediate stages: a compared analysis of DNA fragmentation and apoptotic nuclear morphology

The possible correlation between DNA digestion and changes in nuclear morphology in apoptosis was studied by blocking the apoptotic process at intermediate stages. The apoptogenic action of three drugs: etoposide, puromycin, tributyltin, was contrasted with protease inhibitors with different specificity on U937 cells. The inhibitors interfered with the development of the apoptotic features without shifting cell death to necrosis: treated cells showed abnormal morphologies, which could be recognized as intermediate stages of apoptosis; accordingly, DNA analysis showed an inhibitor-dependent block of the apoptotic DNA digestion. The comparison between size of DNA fragments and nuclear morphology suggested the following correlations: loss of normal nuclear shape with the appearance of a > or = 2 Mb DNA band; ongoing chromatin condensation with the progressive DNA digestion up to 50 kb; nuclear fragmentation with DNA laddering. Protease inhibitors in etoposide-treated cells did not allow the formation of 700-300 kb fragments, suggesting that they possibly derive from a cell-mediated effect.

Different basal NAD levels determine opposite effects of poly(ADP-ribosyl)polymerase inhibitors on H2O2-induced apoptosis

We have recently described that poly(ADP-ribosyl)-polymerase (PARP) inhibitors rescue U937 cells from apoptosis induced by 1 mM H2O2 oxidative stress; PARP activation leads to a reversible drop in NAD level, which could be blocked by PARP inhibitors (Nos-seri et al., 1994, Exp. Cell Res. 212, 367-373). A phenotypic variant of U937 is characterized by a lower basal NAD level (low NAD, LN U937, as opposed to the original high NAD, HN U937). In LN cells treatment with 1 mM H2O2, although activating PARP, does not lower NAD concentration; puzzlingly, PARP inhibitors increase (instead of decreasing, as occurs in HN cells) the extent of stress-induced apoptosis, leading to a reduced cell survival. NAD concentration could be increased in LN cells by adding nicotinamide (5-and 25-fold increase) to the culture medium. These cells (LN+) behaved as HN U937: oxidative stress induced a NAD drop, the extent of which is dependent on the cells' basal NAD level; moreover, PARP inhibitors could rescue LN+ cells from peroxide-induced apoptosis. H2O2-induced apoptosis is not triggered by NAD depletion, but instead it takes place only when NAD levels have been preserved or have recovered: on HN U937, peroxide doses (5 and 10 mM) which lead to necrosis induce an irreversible NAD drop, whereas apoptosis occurs only at lower doses, where NAD depletion is reversible; on LN cells NAD levels do not drop even upon 10 mM H2O2 treatment, and these cells die only by apoptosis; moreover, in HN cells apoptosis is not detectable until 8 h posttreatment, when NAD levels recover, whereas in LN cells, where NAD is always present, apoptosis begins to take place as early as 3 h after stress.

The increase in H2O2-induced apoptosis by ADP-ribosylation inhibitors is related to cell blebbing

HN and LN are two phenotypic variants of the U937 monocytic cell line which differ in their basal NAD content; they respond in an opposite way to oxidative stress in the presence of the poly(ADP-ribosyl)polymerase (PARP) inhibitors 3-aminobenzamide (3ABA) and nicotinamide (NA): the inhibitors protect HN cells from stress-induced apoptosis, while they enhance it on LN cells (Coppola et al., 1995, Exp. Cell Res. 221, 462-469). These opposite effects are due to two overlapping and contrasting phenomena occurring in LN cells, as shown by the bi-modal response of stressed LN cells to increasing 3ABA doses. Indeed H2O2-induced apoptosis is enhanced only at high 3ABA concentrations (i.e., sufficient to inhibit also mono-ADP-ribosylations); lower 3ABA concentrations, which specifically inhibit PARP, also protect LN U937 from stress-induced apoptosis. Unlike HN U937, H2O2-induced apoptosis in LN cells is accompanied by cell blebbing. High 3ABA doses strongly enhance blebbing, leading to cellular fragmentation. Blebbing could be blocked by interfering with actin polymerization with cytochalasin B and D: this eliminated the increase in apoptosis due to 3ABA, suggesting that it is indeed the consequence of excess blebbing. This is supported by the unusual finding that in U937 LN stressed in the presence of 3ABA or NA, blebbing, usually a late event in apoptosis, may even precede its onset.

Non-oxidative loss of glutathione in apoptosis via GSH extrusion

Reduced glutathione (GSH) has been hypothesized to play a role in the rescue of cells from apoptosis, by buffering an endogenously induced oxidative stress. We correlated GSH levels and apoptosis in U937 human monocytic cells induced to apoptosis by different agents. All treatments led to depletion of GSH concomitant with the onset of apoptosis. The loss was due to extrusion of GSH outside the cell, while GSSG was not accumulated in the apoptosing cells, nor was it found in the extracellular medium. Modulation of intracellular GSH level did not influence the overall extent of apoptosis. We conclude that glutathione loss in apoptosis is not necessarily preceded by an oxidative stress, and that GSH depletion alone is not sufficient to lead cells to apoptosis.

Effects of parenteral diclofenac sodium on upper gastrointestinal motility after food in man

In experimental animal models nonsteroidal anti-inflammatory drugs may influence gastrointestinal motility, but as evidence is lacking in man. The effect of diclofenac sodium 75 mg i.m. on the motor response of the upper gastrointestinal tract to food has been studied by manometry in 9 healthy volunteers. Diclofenac had no effect on the motor activity of the stomach, duodenum, or jejunum after a 605 kcal meal.

Intranasal and intramuscular human calcitonin in female osteoporosis and in Paget's disease of bones: a pilot study

It has been shown that human calcitonin (hCT) is absorbed through the nasal mucosa when administered together with promoters like sodium glycocholate (SGC) or dihydrofusinate. The aim of this study was to compare the clinical and metabolic effect of intranasal (in) and intramuscular (im) hCT in patients with osteoporosis or with Paget's disease of bones. Fifteen women with postmenopausal or with senile osteoporosis entered a randomized six months trial with in hCT (plus SGC) or with im hCT 100 U on alternate days. Six women in each group were treated for 2 months, and only four women in each group continued treatment for an additional 4 months period. In hCT, but not im hCT, reduced subjective pain, while urinary cAMP increased to a similar extent in the 2 groups. Other metabolic indexes and bone mineral content (BMC) were unchanged, no new fractures took place, and side effects were fewer with in than with im hCT. To confirm the analgesic effect of in hCT, twelve patients with Paget's disease of bone were randomly treated for 20 days with in or im hCT 100 U/day: during the short period of treatment, pain was reduced by in, not by im hCT, and urinary cAMP excretion similarly increased in the two groups of patients.

Non-steroidal anti-inflammatory drugs as the first step in cancer pain therapy: double-blind, within-patient study comparing nine drugs

The efficacy and tolerability of acetylsalicylic acid, paracetamol, diclofenac, ibuprofen, indomethacin, pirprofen, sulindac, naproxen and suprofen were compared in the treatment of cancer pain. In a double-blind, within-patient randomized study, each drug was given for 1 week to eight patients and for another week to a further eight patients. A total of 65 patients were effectively treated; only 48 completed week 1 and 41 completed week 2. Naproxen, diclofenac and indomethacin were highly effective in pain relief (tested by means of a 100 mm visual analogue scale) and were relatively well tolerated. It is concluded that these non-steroidal anti-inflammatory drugs can be considered as first choice in the treatment of cancer pain.

Pirprofen in the treatment of sports injuries

Patients with sports injuries were treated with pirprofen, a non-steroidal anti-inflammatory drug, in two separate studies. In the single centre study, 39 athletes were treated with 1000 mg/day pirprofen for 2 weeks. In the multicentre study, a further 80 athletes were treated with a variable dosage (600-1200 mg/day) until the disappearance of symptoms, but for no longer than 2 weeks. Efficacy was considered excellent or good in 99/119 (83%) of the patients treated. The clinical variables of pain and mobility significantly (P less than 0.05) improved after 1 week of treatment. Tolerability was satisfactory, the main side-effects involving the gastro-intestinal tract.

The diffusion of pirprofen into the cerebrospinal fluid in man

We have measured the concentrations of pirprofen at various times in plasma and cerebrospinal fluid (CSF) samples, drawn during diagnostic myelography from 28 patients affected by sciatica. After intramuscular injection of 400 mg plasma concentrations of pirprofen reached a peak in 60 min then fell slowly. In contrast, the CSF concentration rose until 12 h and then fell. Pirprofen rapidly crossed the blood-brain barrier and was detectable in CSF at 15-30 min after injection. These results support the suggested hypothesis of a central analgesic action of pirprofen along with the known peripheral one. A new sensitive HPLC method was developed for measuring the concentration of pirprofen in the CSF.

Pharmacokinetics of pirprofen and its pyrrol metabolite in elderly patients

Plasma concentrations of pirprofen and of its pyrrol metabolite were assessed in 9 elderly patients (3 males, 6 females; mean age 76 years) suffering from chronic degenerative disease. Pirprofen 400 mg in 4 ml was administered i.m. and the pharmacokinetic profile of the drug and the metabolite was calculated. The AUC, Cmax and t1/2 of pirprofen were similar to those found in previous studies, and, as expected, those parameters for the pyrrol metabolite were lower (Cmax = 2.8 micrograms/ml-1; tmax = 6.4 h; AUC(0-32) = 56.5 micrograms.h.ml-1). One patient (n = 8) showed different pharmacokinetic behaviour, which is discussed. The data suggest that age has little influence on the pharmacokinetic of pirprofen, although unpredictable responses should always be considered in clinical practice.