Simona Martinotti

Wound healing properties of jojoba liquid wax: an in vitro study.

AIM OF THE STUDY The wound healing properties of jojoba (Simmondsia chinensis) liquid wax (JLW) were studied in vitro on HaCaT keratinocytes and human dermal fibroblasts, which are involved in wounded skin repair. MATERIALS AND METHODS JLW cytotoxicity was evaluated by the crystal violet staining and the neutral red uptake endpoint. Induction of wound healing by JLW was assessed by scratch wound assay on cell monolayers. The involvement of signaling pathways was evaluated by the use of the Ca(2+) chelator BAPTA and of kinase inhibitors, and by Western blot analysis of cell lysates using anti-phospho antibodies. Collagen and gelatinase secretion by cells were assayed by in-cell ELISA and zymography analysis, respectively. RESULTS Cytotoxicity assays showed that the toxic effects of JLW to these cells are extremely low. Scratch wound experiments showed that JLW notably accelerates the wound closure of both keratinocytes and fibroblasts. The use of inhibitors and Western blot revealed that the mechanism of action of JLW is strictly Ca(2+) dependent and requires the involvement of the PI3K-Akt-mTOR pathway and of the p38 and ERK1/2 MAPKs. In addition, JLW was found to stimulate collagen I synthesis in fibroblasts, while no effect was detected on the secretion of MMP-2 and MMP-9 gelatinases by HaCaT or fibroblasts. CONCLUSIONS Taken together, data provide a pharmacological characterization of JLW properties on skin cells and suggest that it could be used in the treatment of wounds in clinical settings.

Epithelial mesenchymal transition traits in honey-driven keratinocyte wound healing: comparison among different honeys.

Honey has been used since ancient times for wound repair, but the subjacent mechanisms are almost unknown. We have tried to elucidate the modulatory role of honey in an in vitro model of HaCaT keratinocyte re‐epithelialization by using acacia, buckwheat, and manuka honeys. Scratch wound and migration assays showed similar increases of re‐epithelialization rates and chemoattractant effects in the presence of different types of honey (0.1%, v/v). However, the use of kinase and calcium inhibitors suggested the occurrence of different mechanisms. All honeys activated cyclin‐dependent kinase 2, focal adhesion kinase, and rasGAP SH3 binding protein 1. However, vasodilator‐stimulated phosphoprotein, integrin‐β3, cdc25C, and p42/44 mitogen activated protein kinase showed variable activation pattern. Re‐epithelialization recapitulates traits of epithelial‐mesenchymal transition (EMT) and the induction of this process was evaluated by a polymerase chain reaction array, revealing marked differences among honeys. Manuka induced few significant changes in the expression of EMT‐regulatory genes, while the other two honeys acted on a wider number of genes and partially showed a common profile of up‐ and down‐regulation. In conclusion, our findings have shown that honey‐driven wound repair goes through the activation of keratinocyte re‐epithelialization, but the ability of inducing EMT varies sensibly among honeys, according to their botanical origin.

In vitro screening of synergistic ascorbate–drug combinations for the treatment of malignant mesothelioma

Malignant mesothelioma (MMe) is a lethal tumor arising from the mesothelium of serous cavities as a result of exposure to asbestos. Current clinical standards consist of combined treatments, but an effective therapy has not been established yet and there is an urgent need for new curative approaches. Ascorbate is a nutrient that is also known as a remedy in the treatment of cancer. In the present study, we have tested the cytotoxicity of ascorbate to MMe cells in combination with drugs used in MMe therapy, such as cisplatin, etoposide, gemcitabine, imatinib, paclitaxel, and raltitrexed, as well as with promising antitumor compounds like taurolidine, α-tocopherol succinate, and epigallocatechin-3-gallate (EGCG). Dose-response curves obtained for each compound by applying the neutral red uptake (NRU) assay to MMe cells growing in vitro, allowed to obtain IC50 values for each compound used singularly. Thereafter, NRU data obtained from each ascorbate/drug combination were analyzed through Tallaridas isobolograms at the IC50 level (Tallarida, 2000), revealing synergistic interactions for ascorbate/gemcitabine and ascorbate/EGCG. These results were further confirmed through comparisons between theoretical additivity IC50 and observed IC50 from fixed-ratio dose-response curves, and over a broad range of IC levels, by using Chou and Talalays combination index (Chou and Talalay, 1984). Synergistic interactions were also shown by examining apoptosis and necrosis rates, using the caspase 3 and lactic dehydrogenase assays, respectively. Hence, data indicate that ascorbate/gemcitabine and ascorbate/EGCG affect synergistically the viability of MMe cells and suggest their possible use in the clinical treatment of this problematic cancer.

Platelet lysate modulates MMP-2 and MMP-9 expression, matrix deposition and cell-to-matrix adhesion in keratinocytes and fibroblasts

Abstract:  Cell–matrix interactions are an essential element of wound healing, while platelet derivatives are used in clinical settings for the treatment of chronic wounds. We used a platelet lysate (PL), which had been previously shown to accelerate in vitro the wounding of HaCaT keratinocytes and fibroblasts (J Cell Mol Med, 13, 2009, 2030; Br J Dermatol, 159, 2008, 537), to study the modulation of MMP‐2 and MMP‐9 collagenase expression, collagen type I and III production and syndecan‐4 expression and rearrangement in these cells. Zymography and Western blot analyses showed that exposure to 20% (v/v) PL for 24 h induced an apparently ERK1/2‐ and p38‐dependent, NF‐kappaB‐independent, translational upregulation of MMP‐9 in HaCaT, while HaCaT MMP‐2 and fibroblast collagenases were almost unaffected. The use of in‐cell ELISA showed that PL induced an increase in the collagen III production of fibroblasts. In‐cell ELISA and immunofluorescence microscopy revealed an increase in the expression of syndecan‐4 and its rearrangement to form focal adhesions in both cell types after PL exposure. Taken together, data indicate that PL promotes keratinocyte epithelialization and regulates fibroblast matrix deposition, thus providing a molecular basis for the ability of this platelet derivative to heal severe and problematic wounds without leading to heavy scarring and keloid formation.

Epigallocatechin-3-gallate induces mesothelioma cell death via H2O2−dependent T-type Ca2+ channel opening

Malignant mesothelioma (MMe) is a highly aggressive, lethal tumour requiring the development of more effective therapies. The green tea polyphenol epigallocathechin‐3‐gallate (EGCG) inhibits the growth of many types of cancer cells. We found that EGCG is selectively cytotoxic to MMe cells with respect to normal mesothelial cells. MMe cell viability was inhibited by predominant induction of apoptosis at lower doses and necrosis at higher doses. EGCG elicited H2O2 release in cell cultures, and exogenous catalase (CAT) abrogated EGCG‐induced cytotoxicity, apoptosis and necrosis. Confocal imaging of fluo 3‐loaded, EGCG‐exposed MMe cells showed significant [Ca2+]i rise, prevented by CAT, dithiothreitol or the T‐type Ca2+ channel blockers mibefradil and NiCl2. Cell loading with dihydrorhodamine 123 revealed EGCG‐induced ROS production, prevented by CAT, mibefradil or the Ca2+ chelator BAPTA‐AM. Direct exposure of cells to H2O2 produced similar effects on Ca2+ and ROS, and these effects were prevented by the same inhibitors. Sensitivity of REN cells to EGCG was correlated with higher expression of Cav3.2 T‐type Ca2+ channels in these cells, compared to normal mesothelium. Also, Cav3.2 siRNA on MMe cells reduced in vitro EGCG cytotoxicity and abated apoptosis and necrosis. Intriguingly, Cav3.2 expression was observed in malignant pleural mesothelioma biopsies from patients, but not in normal pleura. In conclusion, data showed the expression of T‐type Ca2+ channels in MMe tissue and their role in EGCG selective cytotoxicity to MMe cells, suggesting the possible use of these channels as a novel MMe pharmacological target.

Propolis: a new frontier for wound healing?

Propolis is a resin produced by honeybees by mixing wax, pollen, salivary secretions, and collected natural resins.The precise composition of propolis varies with the source, and over 300 chemical components belonging to the flavonoids, terpenes, and phenolic acids have been identified in propolis. Moreover, its chemical composition is subjected to the geographical location, botanical origin, and bee species.Propolis and its compounds have been the focus of many works due to their antimicrobial and anti-inflammatory activity; however, it is now recognized that propolis also possesses regenerative properties.There is an increasing interest in the healing potential of natural products, considering the availability and low cost of these products. Propolis contains a huge number of compounds that explicate some biological effects that speeds up the healing process and is widely used in folk remedies.This review aims to condense the results on the mechanism of activity of propolis and its compounds.

Usnic acid enamines with remarkable cicatrizing properties

Wound healing is a significant concern in many pathologies (post-surgeries, burns, scars) and the search for new chemical entities is advisable. The lichen compound (+)-usnic acid (1) has found application in dermatological and cosmetic preparations, due to its bacteriostatic and antioxidant activities. The compound has also been shown to stimulate the wound closure of keratinocyte monolayers at subtoxic doses. Here we describe the design and synthesis of usnic acid enamines (compounds 2-11), obtained through nucleophilic attack of amino acids or decarboxyamino acids at the acyl carbonyl of the enolized 1,3 diketone. The wound repair properties of these derivatives were evaluated using in vitro and in vivo assays. Compounds 8 and 9 combine low cytotoxicity with high wound healing performance, suggesting their possible use in wound healing-promoting or antiage skin preparations.

Preclinical Demonstration of Synergistic Active Nutrients/Drug (AND) Combination as a Potential Treatment for Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a poor prognosis disease lacking adequate therapy. We have previously shown that ascorbic acid administration is toxic to MPM cells. Here we evaluated a new combined therapy consisting of ascorbate/epigallocatechin-3-gallate/gemcitabine mixture (called AND, for Active Nutrients/Drug). In vitro effects of AND therapy on various MPM cell lines revealed a synergistic cytotoxic mechanism. In vivo experiments on a xenograft mouse model for MPM, obtained by REN cells injection in immunocompromised mice, showed that AND strongly reduced the size of primary tumor as well as the number and size of metastases, and prevented abdominal hemorrhage. Kaplan Meier curves and the log-rank test indicated a marked increase in the survival of AND-treated animals. Histochemical analysis of dissected tumors showed that AND induced a shift from cell proliferation to apoptosis in cancer cells. Lysates of tumors from AND-treated mice, analyzed with an antibody array, revealed decreased TIMP-1 and -2 expressions and no effects on angiogenesis regulating factors. Multiplex analysis for signaling protein phosphorylation exhibited inactivation of cell proliferation pathways. The complex of data showed that the AND treatment is synergistic in vitro on MPM cells, and blocks in vivo tumor progression and metastasization in REN-based xenografts. Hence, the AND combination is proposed as a new treatment for MPM.

Flavonoid oligoglycosides from Ophioglossum vulgatum L. having wound healing properties.

Two new glycosylated and acylated flavonols, viz. quercetin-3-O-[(6-caffeoyl)-β-glucopyranosyl (1 → 3) α-rhamnopyranoside]-7-O-α-rhamnopyranoside (2), and kaempferol-3-O-[(6-caffeoyl)-β-glucopyranosyl (1 → 3) α-rhamnopyranoside]-7-O-α-rhamnopyranoside (3), together with the known quercetin-3-O-methyl ether (1), were isolated from the aerial parts of the fern Ophioglossum vulgatum L. Their structures were established by means of 1D and 2D NMR spectra, as well as ESI-MS and ESI-HRMS spectra. Compounds 1-3 were all found to be active in scratch-wound healing assays on keratinocytes, with 3 being the most active one and showing maximum activity at 20 µM.

Emerging roles for HMGB1 protein in immunity, inflammation, and cancer.

High-mobility group box 1 (HMGB1) protein is a member of the highly conserved non-histone DNA binding protein family. First identified in 1973, as one of a group of chromatin-associated proteins with high acidic and basic amino acid content, it was so named for its characteristic rapid mobility in polyacrylamide gel electrophoresis. HMGB1 was later discovered to have another function. It is released from a variety of cells into the extracellular milieu to act on specific cell-surface receptors. In this latter role, HMGB1 is a proinflammatory cytokine that may contribute to many inflammatory diseases, including sepsis. Therefore, HMGB1 regulates intracellular cascades influencing immune cell functions, including chemotaxis and immune modulation. The bioactivity of the HMGB1 is determined by specific posttranslational modifications that regulate its role in inflammation and immunity. During tumor development, HMGB1 has been reported to play paradoxical roles in promoting both cell survival and death by regulating multiple signaling pathways. In this review, we focus on the role of HMGB1 in physiological and pathological responses, as well as the mechanisms by which it contributes to immunity, inflammation, and cancer progression.