Visible Light Is a Better Co-Inducer of Apoptosis for Curcumin-Treated Human Melanoma Cells than UVA

Curcumin attracts worldwide scientific interest due to its anti-proliferative and apoptosis inducing effects on different tumor cells at concentrations ranging from 10 to 150 µM (3.7–55 µg/ml). Unfortunately, because of a low oral bioavailability, only low and pharmacologically ineffective serum levels are achievable. In this study, an alternative treatment concept consisting of low concentration curcumin (0.2–5 µg/ml) and irradiation with UVA or visible light (VL) has been tested. The experimental results show clearly that this treatment decreases the proliferation and the viability of human melanoma cells while the cell membrane integrity remains intact. We identified the onset of apoptosis characterized by typical markers such as active caspases 8, 9 and 3 as well as DNA fragmentation accompanied by the loss of cell adhesion. The mitochondrial apoptosis signaling pathway is predominant due to an early activation of caspase-9. The present data indicate a higher efficacy of a combination of curcumin and VL than curcumin and UVA. Reduced effects as a result of light absorption by heavily pigmented skin are unlikely if VL is used. These results indicate that a combination of curcumin and light irradiation may be a useful additional therapy in the treatment of malignant disease.     

LED Light-Induced ROS Differentially Regulates Focal Adhesion Kinase Activity in HaCaT Cell Viability

In this study, changes in cell signaling mechanisms in skin cells induced by various wavelengths and intensities of light-emitting diodes (LED) were investigated, focusing on the activity of focal adhesion kinase (FAK) in particular. We examined the effect of LED irradiation on cell survival, the generation of intracellular reactive oxygen species (ROS), and the activity of various cell-signaling proteins. Red LED light increased cell viability at all intensities, whereas strong green and blue LED light reduced cell viability, and this effect was reversed by NAC or DPI treatment. Red LED light caused an increase in ROS formation according to the increase in the intensity of the LED light, and green and blue LED lights led to sharp increases in ROS formation. In the initial reaction to LEDs, red LED light only increased the phosphorylation of FAK and extracellular-signal regulated protein kinase (ERK), whereas green and blue LED lights increased the phosphorylation of inhibitory-κB Kinase α (IKKα), c-jun N-terminal kinase (JNK), and p38. The phosphorylation of these intracellular proteins was reduced via FAK inhibitor, NAC, and DPI treatments. Even after 24 h of LED irradiation, the activity of FAK and ERK appeared in cells treated with red LED light but did not appear in cells treated with green and blue LED lights. Furthermore, the activity of caspase-3 was confirmed along with cell detachment. Therefore, our results suggest that red LED light induced mitogenic effects via low levels of ROS–FAK–ERK, while green and blue LED lights induced cytotoxic effects via cellular stress and apoptosis signaling resulting from high levels of ROS.     

Curcumin Inhibits Imiquimod-Induced Psoriasis-Like Inflammation by Inhibiting IL-1beta and IL-6 Production in Mice

Curcumin, a selective phosphorylase kinase inhibitor, is a naturally occurring phytochemical present in turmeric. Curcumin has been confirmed to have anti-inflammatory properties in addition to the ability to decrease the expression of pro-inflammatory cytokines in keratinocytes. The interleukin-23 (IL-23)/IL-17A cytokine axis plays a critical role in the pathogenesis of psoriasis. Here, we report that topical use of a curcumin gel formulation strongly inhibited imiquimod (IMQ)-induced psoriasis-like inflammation, the development of which was based on the IL-23/IL-17A axis. IMQ-induced epidermal hyperplasia and inflammation in BALB/c mouse ear was significantly inhibited following curcumin treatment. Real-time PCR showed that mRNA levels of IL-17A, IL-17F, IL-22, IL-1β, IL-6 and TNF-α cytokines were decreased significantly by curcumin in ear skin, an effect similar to that of clobetasol. In addition, we found that curcumin may enhance the proliferation of epidermis γδ T cells but inhibit dermal γδ T cell proliferation. We inferred that curcumin was capable of impacting the IL-23/IL-17A axis by inhibiting IL-1β/IL-6 and then indirectly down-regulating IL-17A/IL-22 production. In conclusion, curcumin can relieve the IMQ-induced psoriasis-like inflammation in a mouse model, similar to the effects of clobetasol. Therefore, we have every reason to expect that curcumin will be used in the treatment of psoriasis in the future.     

Visible light and/or UVA offer a strong amplification of the anti-tumor effect of curcumin

Curcumin, a dietary pigment from the plant Curcuma longa, inhibits cell proliferation and induces apoptosis in different cell lines. The therapeutic benefit is hampered by a very low absorption after trans-dermal or oral application. Therefore, great efforts were undertaken to enhance the effectiveness of curcumin. Recently, it was demonstrated that curcumin offers the described effects also at low concentrations (0.2–1 μg/ml) when applied in combination with UVA or visible light. The efficacy of this combination was shown in human epidermal keratinocytes and in a panel of other cell species in vitro as well as in a xenograft tumor model with A431 tumor cells injected subcutaneously in the flanks of NMRI nude mice in vivo. The treatment of keratinocytes with curcumin and light resulted in the inhibition of cell growth, and in the induction of apoptosis, whereas no toxic cell membrane damage was detectable. The treatment of tumor bearing nude mice with curcumin and visible light resulted in reduced tumor volumes, reduced proliferation rates, and the induction of apoptosis in the tumors. On the molecular level inhibition of extracellular regulated kinases 1/2 and epidermal growth factor receptor was observed which may aid to inhibition of proliferation and induction of apoptosis. This review covers the experiences of the new combination treatment of human tumors.     

Curcumin sensitizes human lung cancer cells to apoptosis and metastasis synergistically combined with carboplatin

Although carboplatin is one of the standard chemotherapeutic agents for non-small cell lung cancer (NSCLC), it has limited therapeutic efficacy due to activation of a survival signaling pathway and the induction of multidrug resistance. Curcumin, a natural compound isolated from the plant Curcuma longa, is known to sensitize tumors to different chemotherapeutic agents. The aim of this study is to evaluate whether curcumin can chemosensitize lung cancer cells to carboplatin and to analyze the signaling pathway underlying this synergism. We investigated the synergistic effect of both agents on cell proliferation, apoptosis, invasion, migration, and expression of related signaling proteins using the human NSCLC cell line, A549. A549 cell was treated with different concentrations of curcumin and carboplatin alone and in combination. Combined treatment with curcumin and carboplatin inhibited tumor cell growth, migration, and invasion compared with either drug alone. Matrix metalloproteinase (MMP)-2 and MMP-9 were more efficiently downregulated by co-treatment than by each treatment alone. mRNA and protein expression of caspase-3 and caspase-9 and proapoptotic genes was increased in cells treated with a combination of curcumin and carboplatin, whereas expression of the antiapoptotic Bcl-2 gene was suppressed. Co-treatment of both agents substantially suppressed NF-κB activation and increased expression of p53. Phosphorylation of Akt, a protein upstream of NF-κB, was reduced, resulting in inhibition of the degradation of inhibitor of κB(IκBα), whereas the activity of extracellular signal-regulated kinase (ERK1/2) was enhanced. Our study demonstrated that the synergistic antitumor activity of curcumin combined with carboplatin is mediated by multiple mechanisms involving suppression of NF-κB via inhibition of the Akt/IKKα pathway and enhanced ERK1/2 activity. Based on this mechanism, curcumin has potential as a chemosensitizer for carboplatin in the treatment of patients with NSCLC.     

Antifibrotic effects of curcumin are associated with overexpression of cathepsins K and L in bleomycin treated mice and human fibroblasts

Background

Lung fibrosis is characterized by fibroblast proliferation and the deposition of collagens. Curcumin, a polyphenol antioxidant from the spice tumeric, has been shown to effectively counteract fibroblast proliferation and reducing inflammation and fibrotic progression in animal models of bleomycin-induced lung injury. However, there is little mechanistic insight in the biological activity of curcumin. Here, we study the effects of curcumin on the expression and activity of cathepsins which have been implicated in the development of fibrotic lung diseases.

Methods

We investigated the effects of curcumin administration to bleomycin stimulated C57BL/6 mice and human fetal lung fibroblasts (HFL-1) on the expression of cathepsins K and L which have been implicated in matrix degradation, TGF-β1 modulation, and apoptosis. Lung tissues were evaluated for their contents of cathepsins K and L, collagen, and TGF-β1. HFL-1 cells were used to investigate the effects of curcumin and cathepsin inhibition on cell proliferation, migration, apoptosis, and the expression of cathepsins K and L and TGF-β1.

Results

Collagen deposition in lungs was decreased by 17-28% after curcumin treatment which was accompanied by increased expression levels of cathepsins L (25%-39%) and K (41%-76%) and a 30% decrease in TGF-β1 expression. Moreover, Tunel staining of lung tissue revealed a 33-41% increase in apoptotic cells after curcumin treatment. These in vivo data correlated well with data obtained from the human fibroblast line, HFL-1. Here, cathepsin K and L expression increased 190% and 240%, respectively, in the presence of curcumin and the expression of TGF-β1 decreased by 34%. Furthermore, curcumin significantly decreased cell proliferation and migration and increased the expression of surrogate markers of apoptosis. In contrast, these curcumin effects were partly reversed by a potent cathepsin inhibitor.

Conclusion

This study demonstrates that curcumin increases the expression of cathepsins K and L in lung which an effect on lung fibroblast cell behavior such as proliferation, migration and apoptosis rates and on the expression of TGF-β1 in mouse lung and HFL-1 cells. These results suggest that cathepsin-inducing drugs such as curcumin may be beneficial in the treatment of lung fibrosis.     

Inhibition of p38 MAPK Signaling Augments Skin Tumorigenesis via NOX2 Driven ROS Generation

p38 mitogen-activated protein kinases (MAPKs) respond to a wide range of extracellular stimuli. While the inhibition of p38 signaling is implicated in the impaired capacity to repair ultraviolet (UV)-induced DNA damage—a primary risk factor for human skin cancers—its mechanism of action in skin carcinogenesis remains unclear, as both anti-proliferative and survival functions have been previously described. In this study, we utilized cultured keratinocytes, murine tumorigenesis models, and human cutaneous squamous cell carcinoma (SCC) specimens to assess the effect of p38 in this regard. UV irradiation of normal human keratinocytes increased the expression of all four p38 isoforms (α/β/γ/δ); whereas irradiation of p53-deficient A431 keratinocytes derived from a human SCC selectively decreased p38α, without affecting other isoforms. p38α levels are decreased in the majority of human cutaneous SCCs assessed by tissue microarray, suggesting a tumor-suppressive effect of p38α in SCC pathogenesis. Genetic and pharmacological inhibition of p38α and in A431 cells increased cell proliferation, which was in turn associated with increases in NAPDH oxidase (NOX2) activity as well as intracellular reactive oxygen species (ROS). These changes led to enhanced invasiveness of A431 cells as assessed by the matrigel invasion assay. Chronic treatment of p53^-/-/SKH-1 mice with the p38 inhibitor SB203580 accelerated UV-induced SCC carcinogenesis and increased the expression of NOX2. NOX2 knockdown suppressed the augmented growth of A431 xenografts treated with SB203580. These findings indicate that in the absence of p53, p38α deficiency drives SCC growth and progression that is associated with enhanced NOX2 expression and ROS formation.     

Curcumin Enhances the Effect of Chemotherapy against Colorectal Cancer Cells by Inhibition of NF-κB and Src Protein Kinase Signaling Pathways

Objective

Development of treatment resistance and adverse toxicity associated with classical chemotherapeutic agents highlights the need for safer and effective therapeutic approaches. Herein, we examined the effectiveness of a combination treatment regimen of 5-fluorouracil (5-FU) and curcumin in colorectal cancer (CRC) cells.

Methods

Wild type HCT116 cells and HCT116+ch3 cells (complemented with chromosome 3) were treated with curcumin and 5-FU in a time- and dose-dependent manner and evaluated by cell proliferation assays, DAPI staining, transmission electron microscopy, cell cycle analysis and immunoblotting for key signaling proteins.

Results

The individual IC₅₀ of curcumin and 5-FU were approximately 20 µM and 5 µM in HCT116 cells and 5 µM and 1 µM in HCT116+ch3 cells, respectively (p<0.05). Pretreatment with curcumin significantly reduced survival in both cells; HCT116+ch3 cells were considerably more sensitive to treatment with curcumin and/or 5-FU than wild-type HCT116 cells. The IC₅₀ values for combination treatment were approximately 5 µM and 1 µM in HCT116 and 5 µM and 0.1 µM in HCT116+ch3, respectively (p<0.05). Curcumin induced apoptosis in both cells by inducing mitochondrial degeneration and cytochrome c release. Cell cycle analysis revealed that the anti-proliferative effect of curcumin and/or 5-FU was preceded by accumulation of CRC cells in the S cell cycle phase and induction of apoptosis. Curcumin potentiated 5-FU-induced expression or cleavage of pro-apoptotic proteins (caspase-8, -9, -3, PARP and Bax), and down-regulated anti-apoptotic (Bcl-xL) and proliferative (cyclin D1) proteins. Although 5-FU activated NF-κB/PI-3K/Src pathway in CRC cells, this was down-regulated by curcumin treatment through inhibition of IκBα kinase activation and IκBα phosphorylation.

Conclusions

Combining curcumin with conventional chemotherapeutic agents such as 5-FU could provide more effective treatment strategies against chemoresistant colon cancer cells. The mechanisms involved may be mediated via NF-κB/PI-3K/Src pathways and NF-κB regulated gene products.     

Light‐emitting diode irradiation induces AKT/mTOR‐mediated apoptosis in human pancreatic cancer cells and xenograft mouse model

The beneficial effects of light‐emitting diode (LED) irradiation have been reported in various pathologies, including cancer. However, its effect in pancreatic cancer cells remains unclear. Herein, we demonstrated that blue LED of 460 nm regulated pancreatic cancer cell proliferation and apoptosis by suppressing the expression of apoptosis‐related factors, such as mutant p53 and B‐cell lymphoma 2 (Bcl‐2), and decreasing the expression of RAC‐β serine/threonine kinase 2 (AKT2), the phosphorylation of protein kinase B (AKT), and mammalian target of rapamycin (mTOR). Blue LED irradiation also increased the levels of cleaved poly‐(ADP‐ribose) polymerase (PARP) and caspase‐3 in pancreatic cancer cells, while it suppressed AKT2 expression and inhibited tumor growth in xenograft tumor tissues. In conclusion, blue LED irradiation suppressed pancreatic cancer cell and tumor growth by regulating AKT/mTOR signaling. Our findings indicated that blue LEDs could be used as a nonpharmacological treatment for pancreatic cancer.     

Fast Fluorescence Quenching from Isolated Guard Cell Chloroplasts of Vicia faba Is Induced by Blue Light and Not by Red Light

Chlorophyll a fluorescence transients from isolated Vicia faba guard cell chloroplasts were used to probe the response of these organelles to light quality. Guard cell chloroplasts were isolated from protoplasts by passing them through a 10-μm nylon net. Intact chloroplasts were purified on a Percoll gradient. Chlorophyll a fluorescence transients induced by actinic red or blue light were measured with a fluorometer equipped with a measuring beam. Actinic red light induced a monophasic quenching, and transients induced by blue light showed biphasic kinetics having a slow and a fast component. The difference between the red and blue light-induced transients could be observed over a range of fluence rates tested (200-800 μmol m⁻² s⁻¹). The threshold fluence rate of blue light for the induction of the fast component of quenching was 200 μmol m⁻² s⁻¹, but in the presence of saturating red light, fluence rates as low as 25 μmol m⁻² s⁻¹ induced the fast quenching. These results indicate that guard cell chloroplasts have a specific response to blue light.     

LED不同光质对萝卜愈伤组织诱导、增殖和萝卜硫素含量的影响

以白水萝卜无菌苗及其愈伤组织为实验材料,研究其在LED白、红、黄、蓝、绿和蓝红6种光质下的愈伤诱导和增殖。结果表明：LED不同光质下胚轴愈伤组织的诱导效应不同,诱导率顺序依次为黄光〉红光〉蓝红光〉白光〉蓝光〉绿光;蓝光、黄光和红光有利于子叶愈伤组织的诱导;子叶诱导愈伤组织的效果较下胚轴好;LED红光下愈伤组织的增殖倍数和萝卜硫素含量均为最高。     

Inhibition of ROS-NF-κB-dependent autophagy enhances Hypocrellin A united LED red light-induced apoptosis in squamous carcinoma A431 cells

Cutaneous squamous cell carcinoma (cSCC) is a type of malignant skin tumor derived from epidermal Malpighian cells. Photodynamic therapy is regarded as a crucial method in oncology. Hypocrellin A (HA), an efficient natural photosensitizer, has been reported to exert excellent light induced antiviral, antimicrobial and anticancer activity through mediating multiple signaling pathways. The purpose of the present study is to examine the effects of HA united red light irradiation on human squamous carcinoma A431 cells and further reveal the underlying regulatory mechanisms. The results showed that synergistic treatment of HA and red light irradiation inhibited cell proliferation and induced cell apoptosis and autophagy. Moreover, HA united red light irradiation caused a significant accumulation of reactive oxygen species (ROS), and induced the activation of c-Jun NH 2 terminal kinases (JNKs) which was inhibited by the antioxidant N-Acetyl-cysteine (NAC). Furthermore, HA united red light irradiation activated the nuclear factor-kappa B (NF-κB) pathway, and inhibition of NF-κB activity exacerbated HA united red light irradiation-induced apoptosis but suppressed cell autophagy. In addition, the inhibition of autophagy promoted HA united red light irradiation-induced apoptosis and facilitated the NF-κB activity. Over all, our results revealed that HA united red light irradiation could inhibit A431 cell proliferation by inducing apoptosis and autophagy via the activation of the ROS mediated JNK and NF-κB pathways, providing prospective for HA as a potential therapeutic for the treatment of cSCC.     

An Important Role of α-Hemolysin in Extracellular Vesicles on the Development of Atopic Dermatitis Induced by Staphylococcus aureus

Skin barrier disruption and dermal inflammation are key phenotypes of atopic dermatitis (AD). Staphylococcus aureus secretes extracellular vesicles (EVs), which are involved in AD pathogenesis. Here, we evaluated the role of EVs-associated α-hemolysin derived from S. aureus in AD pathogenesis. α-hemolysin production from S. aureus was detected using western blot analyses. The cytotoxic activity of α-hemolysin on HaCaT keratinocytes was evaluated by measuring cell viability after treating cells with soluble and EVs-associated α-hemolysin. To determine the type of cell death, HaCaT keratinocytes were stained with annexin V and 7-AAD. The in vivo effects of α-hemolysin were evaluated by application of soluble and EV-associated α-hemolysin on the mouse skin. The present study showed that increased α-hemolysin was produced by S. aureus colonized on AD patients compared to healthy subjects. α-hemolysin production was also related to AD severity. In addition, EV-associated α-hemolysin was more cytotoxic to HaCaT keratinocytes than soluble α-hemolysin, and α-hemolysin-negative EVs did not induce keratinocyte death. EV-associated α-hemolysin induced necrosis, but soluble α-hemolysin induced apoptosis of keratinocytes. In vivo, skin barrier disruption and epidermal hyperplasia were induced by soluble and EV-associated α-hemolysin. However, AD-like dermal inflammation was only caused by EV-associated α-hemolysin. Moreover, neither skin barrier disruption nor AD-like skin inflammation was induced by α-hemolysin-negative EVs. Taken together, α-Hemolysin secreted from S. aureus, particularly the EV-associated form, induces both skin barrier disruption and AD-like skin inflammation, suggesting that EV-associated α-hemolysin is a novel diagnostic and therapeutic target for the control of AD.     

Blue light emitting diode induces apoptosis in lymphoid cells by stimulating autophagy

The present study was performed to examine the induction of apoptotic cell death and autophagy by blue LED irradiation, and the contribution of autophagy to apoptosis in B cell lymphoma A20 and RAMOS cells exposed to blue LED. Irradiation with blue LED reduced cell viability and induced apoptotic cell death, as indicated by exposure of phosphatidylserine on the plasma outside membrane and fragmentation of DNA. Furthermore, the mitochondrial membrane potential increased, and apoptotic proteins (PARP, caspase 3, Bax, and bcl-2) were observed. In addition, the level of intracellular superoxide anion (O₂⁻) gradually increased. Interestingly the formation of autophagosomes and level of LC3-II were increased in blue LED-irradiated A20 and RAMOS cells, but inhibited after pretreatment with 3-methyladenine (3-MA), widely used as an autophagy inhibitor. Inhibition of the autophagic process by pretreatment with 3-MA blocked blue LED irradiation-induced caspase-3 activation. Moreover, a significant reduction of both the early and late phases of apoptosis after transfection with ATG5 and beclin 1 siRNAs was shown by the annexin V/PI staining, indicating a crucial role of autophagy in blue LED-induced apoptosis in cells. Additionally, the survival rate of mice irradiated with blue LED after injection with A20 cells increased compared to the control group. Our data demonstrate that blue LED irradiation induces apoptosis via the mitochondrial-mediated pathway, in conjunction with autophagy. Further studies are needed to elucidate the precise mechanism of blue LED-induced immune cell death.     

Curcumin ameliorates TNF-α-induced ICAM-1 expression and subsequent THP-1 adhesiveness via the induction of heme oxygenase-1 in the HaCaT cells

Adhesion molecules such as ICAM-1 are important in the infiltration of leukocytes into the site of inflammation. In this study, we investigated the inhibitory effects of curcumin on ICAM-1 expression and monocyte adhesiveness as well as its underlying action mechanism in the TNF-α-stimulated keratinocytes. Curcumin induced expression of heme oxygenase-1 (HO-1) in the human keratinocyte cell line HaCaT. In addition, curcumin induced Nrf2 activation in dose- and time-dependent manners in the HaCaT cells. Curcumin suppressed TNF-α- induced ICAM-1 expression and subsequent monocyte adhesion, which were reversed by the addition of tin protoporphyrin IX (SnPP), a specific inhibitor of HO-1, or HO-1 knockdown using siRNA. Furthermore, Nrf2 knockdown using siRNA reversed the inhibitory effect of curcumin on the TNF-α-induced ICAM-1 expression and adhesion of monocytes to keratinocytes. These results suggest that curcumin may exert its anti-inflammatory activity by suppressing the TNF-α-induced ICAM-1 expression and subsequent monocyte adhesion via expression of HO-1 in the keratinocytes. [BMB Reports 2013;46(8): 410-415]     

Effect of blue light‐emitting diode light and antioxidant potential in a somatic cell

Light is an indispensable part of routine laboratory work in which conventional light is generally used. Light‐emitting diodes (LEDs) have come to replace conventional light, and thus could be a potent target in biomedical studies. Since blue light is a major component of visible light wavelength, in this study, using a somatic cell from the African green monkey kidney, we assessed the possible consequences of the blue spectra of LED light in future animal experiments and proposed a potent mitigation against light‐induced damage. COS‐7 cells were exposed to blue LED light (450 nm) and the growth and deoxyribonucleic acid (DNA) damage were assessed at different exposure times. A higher suppression in cell growth and viability was observed under a longer period of blue LED light exposure. The number of apoptotic cells increased as the light exposure time was prolonged. Reactive oxygen species (ROS) generation was also elevated in accordance to the extension of light exposure time. A comparison with dark‐maintained cells revealed that the upregulation of ROS by blue LED light plays a significant role in causing cellular dysfunction in DNA in a time‐dependent manner. In turn, antioxidant treatment has been shown to improve cell growth and viability under blue LED light conditions. This indicates that antioxidants have potential against blue LED light‐induced somatic cell damage. It is expected that this study will contribute to the understanding of the basic mechanism of somatic cell death under visible light and maximize the beneficial use of LED light in future animal experiments.     

Resveratrol Induces Long-Lasting IL-8 Expression and Peculiar EGFR Activation/Distribution in Human Keratinocytes: Mechanisms and Implications for Skin Administration

Anti-inflammatory and skin tumour preventing effects of resveratrol have been extensively studied pre-clinically and resveratrol has been proposed for clinical investigations. To provide a basis or/and limitations for topical administration to human skin, molecular mechanisms underlying resveratrol effects towards normal human epidermal keratinocytes (NHEK) were evaluated. NHEK were challenged by either resveratrol alone or by its combination with TNFalpha or TGFalpha, and time-dependent molecular events were monitored. Interleukin 8 (IL-8) expression and its mRNA stability, ERK1/2, p65/RelA, and EGFR phosphorylation were determined. Intracellular distribution of EGFR/P-EGFR was measured in the membrane, cytoplasmic, and nuclear fractions. Specific DNA binding activity of NFκB (p65/RelA) and AP-1(c-Fos), NHEK proliferation, and molecular markers of apoptosis/cell cycle were detected. Resveratrol induced delayed, long-lasting and steadily growing IL-8 gene and protein over-expression as well as enhanced EGFR phosphorylation, both abrogated by the EGFR kinase inhibitor PD168393. However, resveratrol did not act as a phosphatase inhibitor. ERK phosphorylation was transiently inhibited at early time-points and activated at 6–24 h. Accordingly, c-Fos-specific DNA binding was increased by resveratrol. Cellular distribution of EGFR/P-EGFR was shifted to membrane and nucleus while cytosolic levels were reduced concomitant with enhanced degradation. Notwithstanding high nuclear levels of EGFR/P-EGFR, spontaneous and TGFalpha-triggered cell proliferation was strongly suppressed by resveratrol mainly through cell cycle arrest.

Conclusions/Significance

Resveratrol synergized with TNFα in the induction of delayed, long-lasting IL-8 expression through sustained EGFR-ERK axis activation. The time course indicates that resveratrol metabolites could be implicated. Topical administration of Resv to psoriatic patients over-expressing TNFα, IL-8 and EGFR-ERK in the skin should be cautiously considered. Since high nuclear levels of EGFR correspond to increased risk of tumorigenesis, chronic resveratrol application to the skin may be potentially dangerous. Wound healing acceleration by resveratrol could not be envisaged due to its anti-proliferative effects towards normal keratinocytes.     

Skin and subcutaneous fat morphology alterations under the LED or laser treatment in rats in vivo

The main objective of this work is to quantify the impact of photodynamic/photothermal treatment by using visible LED and NIR laser irradiation through the skin of subcutaneous fat in vivo followed up by tissue sampling and histology. The optical method may provide reduction of regional or site‐specific accumulations of abdominal or subcutaneous adipose tissue precisely and least‐invasively by inducing cell apoptosis and controlled necrosis of fat tissue. As photodynamic/photothermal adipose tissue sensitizers Brilliant Green (BG) or Indocyanine Green (ICG) dyes were injected subcutaneously in rats. The CW LED device (625 nm) or CW diode laser (808 nm) were used as light sources, respectively. Biopsies of skin together with subcutaneous tissues were taken for histology. The combined action BG‐staining and LED‐irradiation (BG + LED) or ICG‐staining and NIR‐laser irradiation (ICG + NIR) causes pronounced signs of damage of adipose tissue characterized by a strong stretching, thinning, folding and undulating of cell membranes and appearance of necrotic areas. As a posttreatment after 14 days only connective tissue was observed at the site of necrotic areas. The data obtained are important for safe light treatment of site‐specific fat accumulations, including cellulite. This work provides a basis for the development of fat lipolysis technologies and to move them to clinical applications. Schematics of animal experiment.      

Trichophyton rubrum is Inhibited by Free and Nanoparticle Encapsulated Curcumin by Induction of Nitrosative Stress after Photodynamic Activation

Antimicrobial photodynamic inhibition (aPI) utilizes radical stress generated from the excitation of a photosensitizer (PS) with light to destroy pathogens. Its use against Trichophyton rubrum, a dermatophytic fungus with increasing incidence and resistance, has not been well characterized. Our aim was to evaluate the mechanism of action of aPI against T. rubrum using curcumin as the PS in both free and nanoparticle (curc-np) form. Nanocarriers stabilize curcumin and allow for enhanced solubility and PS delivery. Curcumin aPI, at optimal conditions of 10 μg/mL of PS with 10 J/cm² of blue light (417 ± 5 nm), completely inhibited fungal growth (p<0.0001) via induction of reactive oxygen (ROS) and nitrogen species (RNS), which was associated with fungal death by apoptosis. Interestingly, only scavengers of RNS impeded aPI efficacy, suggesting that curcumin acts potently via a nitrosative pathway. The curc-np induced greater NO^• expression and enhanced apoptosis of fungal cells, highlighting curc-np aPI as a potential treatment for T. rubrum skin infections.