Overexpression of Dock180 and Elmo1 in Melanoma is Associated with Cell Survival and Migration.

BACKGROUND: Melanoma is one of the most aggressive and metastatic skin cancers. Although overexpression of Dock180 and Elmo1 has been identified in various cancers, including glioma, ovarian cancer, and breast cancer, their expression and functions in melanoma remain unknown. OBJECTIVE: This study aims to confirm the expression of Dock180 and Elmo1, their underlying mechanisms, and roles in melanoma. METHODS: Both immunohistochemical staining and Western blotting were used to confirm expression of Dock180 and Elmo1 in human melanoma. To identify roles of Dock180 and Elmo1 in cell survival, apoptosis and migration, downregulation of Dock180 or Elmo1 in melanoma cells with small interfering RNA (siRNA) was performed. RESULTS: We identified overexpression of Dock180 and Elmo1 in human melanoma compared to normal skin ex vivo. Inhibition of Dock180 or Elmo1 following siRNA in melanoma cells reduced cell viability and increased apoptosis as supported by increased proportion of cells with Annexin V-PE (+) staining and sub-G0/G1 peak in cell cycle analysis. Moreover, inhibition of Dock180 or Elmo1 regulated apoptosis-related proteins, showing downregulation of Bcl-2, caspase-3, and PARP and upregulation of Bax, PUMA, cleaved caspase-3, and cleaved PARP. Furthermore, knockdown of Dock180 and Elmo1 in melanoma cells reduced cell migration and changed cellular signaling pathways including ERK and AKT. Vemurafenib decreased cell viability in concentration-dependent manner, while transfection with Dock180- or Elmo1-specific siRNA in melanoma cells significantly reduced cell viability. CONCLUSION: Our results suggest that both Dock180 and Elmo1 may be associated with cancer progression, and can be potential targets for treatment of melanoma.

Curcumin Enhances the Anticancer Effects of Binimetinib on Melanoma Cells by Inducing Mitochondrial Dysfunction and Cell Apoptosis with Necroptosis.

BACKGROUND: Recent studies suggest that MEK1/2 inhibitors, including binimetinib, significantly improve malignant melanoma (MM) patient survival. Growing evidence suggests that phytochemicals, especially curcumin, can overcome drug resistance in cancer cells through a variety of mechanisms. OBJECTIVE: This study aims to examine curcumin's efficacy in vitro combined with binimetinib in human MM cells. METHODS: We used 2D monolayer and 3D spheroid human epidermal melanocyte culture models, HEMn-MP (human epidermal melanocytes, neonatal, moderately pigmented), and two human MM cell lines, G361 and SK-MEL-2, to evaluate cell viability, proliferation, migration, death, and reactive oxygen species (ROS) production following single therapy treatment, with either curcumin or binimetinib, or a combination of both. RESULTS: Compared to MM cells treated with single therapy, those with combination therapy showed significantly decreased cell viability and increased ROS production. We observed apoptosis following both single and combination therapies. However only those who had had combination therapy had necroptosis. CONCLUSION: Collectively, our data demonstrates that curcumin exerts significant synergistic anticancer effects on MM cells by inducing ROS and necroptosis when combined with binimetinib. Therefore, a strategy of adding curcumin to conventional anticancer agents holds promise for treating MM.

Concurrent induction of apoptosis and necroptosis in apigenin­treated malignant mesothelioma cells: Reversal of Warburg effect through Akt inhibition and p53 upregulation.

A high dependence on aerobic glycolysis, known as the Warburg effect, is one of the metabolic features exhibited by tumor cells. Therefore, targeting glycolysis is becoming a very promising strategy for the development of anticancer drugs. In the present study, it was investigated whether pre­adaptation of malignant mesothelioma (MM) cells to an acidic environment was associated with a metabolic shift to the Warburg phenotype in energy production, and whether apigenin targets acidosis­driven metabolic reprogramming. Cell viability, glycolytic activity, Annexin V­PE binding activity, reactive oxygen species (ROS) levels, mitochondrial membrane potential, ATP content, western blot analysis and spheroid viability were assessed in the present study. MM cells pre­adapted to lactic acid were resistant to the anticancer drug gemcitabine, increased Akt activation, downregulated p53 expression, and upregulated rate­limiting enzymes in glucose metabolism compared with their parental cells. Apigenin treatment increased cytotoxicity, Akt inactivation and p53 upregulation. Apigenin also reduced glucose uptake along with downregulation of key regulatory enzymes in glycolysis, increased ROS levels with loss of mitochondrial membrane potential, and downregulated the levels of complexes I, III and IV in the mitochondrial electron transport chain with intracellular ATP depletion, resulting in upregulation of molecules mediating apoptosis and necroptosis. Apigenin­induced alterations of cellular responses were similar to those of Akt inactivation by Ly294002. Overall, the present results provide mechanistic evidence supporting the anti­glycolytic and cytotoxic role of apigenin via inhibition of the PI3K/Akt signaling pathway and p53 upregulation.

Data mining for detecting signals of adverse drug reaction of doxycycline using the Korea adverse event reporting system database.

BACKGROUND: Doxycycline is one of the most prescribed antibiotics by dermatologists. However, the concern regarding adverse events of doxycyline has been rising. OBJECTIVE: To detect the adverse events of doxycycline using the Korea Adverse Events Reporting System (KAERS) database from January 2014 to December 2018 through a data mining method. METHODS: A signal was defined as one satisfying all three indices; a proportional reporting ratio, a reporting odds ratio, and an information component. We further checked whether the detected signals exist in drug labels in Korea and five developed countries, the United States, the United Kingdom, Germany, Canada, and Japan. RESULTS: A total of 3,365,186 adverse event-drug pairs were reported and of which 3,075 were associated with doxycycline. Among the thirty-seven signals, nineteen (malaise, ileus, confusion, malignant neoplasm, ectopic pregnancy, ovarian hyperstimulation, vaginal hemorrhage, bone necrosis, acne, rosacea, seborrheic dermatitis, folliculitis, skin ulceration, crusting, dry skin, paronychia, mottled skin, application site reaction, and application site edema) were not included on any of the drug labels of the six countries. CONCLUSION: We identified nineteen new doxycycline signals that did not appear on drug labels in six countries. Further studies are warranted to evaluate the causality of the adverse events with doxycycline.

Bone mineral density and osteoporosis risk in young adults with atopic dermatitis.

Atopic dermatitis (AD) has been increasing worldwide over the past few decades. AD has been reported to be associated with an increased risk of osteoporosis and fractures in adult AD patients. The aim of this study was to investigate the bone mineral density (BMD) to evaluate osteoporosis risk in young adults with AD by sex. This was a case-control cohort study using a national dataset from the Korea National Health and Nutrition Examination Survey 2007-2009. We included young adult AD patients (men aged 19 ≤ and < 50 years, premenopausal women aged 19 ≤ and < 50 years) and 1:5 propensity score weighting controls by age, sex, body mass index (BMI), vitamin D level, and alcohol/smoking status. BMD was measured by double energy X-ray absorptiometry at the lumbar spine, femur neck, and total femur. The prevalence of low BMD, defined by a Z-score ≤ - 2.0, was compared between AD and without AD. We analyzed 311 (weighted n = 817,014) AD patients and 8,972 (weighted n = 20,880,643) controls. BMD at the lumbar spine was significantly lower in the male AD group than in the male control group (mean ± SE, 0.954 ± 0.016 vs. 0.989 ± 0.002, P = 0.03). The prevalence of low BMD (Z-score) did not significantly differ between AD and non-AD subjects in both men (3.8% vs. 2.7%, P = 0.56) and women (6.4% vs. 3.3%, P = 0.40). Among AD patients, early age at diagnosis of AD, longer duration of AD, lower BMI, rural residence (for men), less education, low vitamin D level, late menarche, and more pregnancies (for women) were associated with low BMD. In conclusion, low BMD did not occur more frequently in young adults with AD than in non-AD controls. However, early-onset/longer AD duration and lower BMI were associated with low BMD among young adult patients with AD.

Upregulation of DJ-1 expression in melanoma regulates PTEN/AKT pathway for cell survival and migration.

Cutaneous melanoma is known to be one of the most dangerous skin cancers because of its metastatic functions. Today, it is essential to investigate specific biomarkers for the target treatment in many diseases including cancers. DJ-1 protein, also known as Parkinson disease 7, has various functions associated with cancer progression including cell survival and migration. Phosphatase and tensin homolog (PTEN) is a tumor suppressor that regulates the PI3K/AKT signaling pathway and its mutations have been reported to frequently occur in many cancers such as thyroid, breast and skin. Recently, DJ-1 has been identified as a negative regulator of PTEN in many human cancer cells. However, the impacts and relationship of DJ-1 and PTEN have not been studied yet in melanoma. To confirm the expression of DJ-1 and PTEN in melanoma compared to normal skin tissues and find out functions of DJ-1 in melanoma cells, Western blot analysis and immunohistochemical staining were used. Transfection of G361 cells with DJ-1-specific small interfering RNA was performed to figure out the roles of DJ-1 and the relationship between DJ-1 and PTEN in melanoma cells. In our study, the DJ-1 protein was significantly increased with loss of PTEN protein in melanoma compared to that in normal skin. Inhibition of DJ-1 in G361 cells induced apoptosis, and suppressed cell survival and migration. Furthermore, suppression of DJ-1 in G361 cells increased the expression of cleaved caspase-3, cleaved PARP, Bax, p53, and Daxx as well as PTEN, while it decreased expression of survivin, caspase-3, and PARP. Also, downregulated DJ-1 inhibited phosphorylation of AKT in G361 cells. Collectively, DJ-1 overexpression could affect the proliferative and invasive capabilities of melanoma cells via regulating the PTEN/AKT pathway and apoptosis-related proteins. This study suggests that DJ-1 may be a potential target for the treatment of melanoma.

Apigenin causes necroptosis by inducing ROS accumulation, mitochondrial dysfunction, and ATP depletion in malignant mesothelioma cells.

Apigenin, a naturally occurring flavonoid, is known to exhibit significant anticancer activity. This study was designed to determine the effects of apigenin on two malignant mesothelioma cell lines, MSTO-211H and H2452, and to explore the underlying mechanism(s). Apigenin significantly inhibited cell viability with a concomitant increase in intracellular reactive oxygen species (ROS) and caused the loss of mitochondrial membrane potential (Δ𝚿m), and ATP depletion, resulting in apoptosis and necroptosis in monolayer cell culture. Apigenin upregulated DNA damage response proteins, including the DNA double strand break marker phospho (p)- histone H2A.X. and caused a transition delay at the G2/M phase of cell cycle. Western blot analysis showed that apigenin treatment upregulated protein levels of cleaved caspase-3, cleaved PARP, p-MLKL, and p-RIP3 along with an increased Bax/Bcl-2 ratio. ATP supplementation restored cell viability and levels of DNA damage-, apoptosisand necroptosis-related proteins that apigenin caused. In addition, N-acetylcysteine reduced ROS production and improved Δ𝚿m loss and cell death that were caused by apigenin. In a 3D spheroid culture model, ROS-dependent necroptosis was found to be a mechanism involved in the anti-cancer activity of apigenin against malignant mesothelioma cells. Taken together, our findings suggest that apigenin can induce ROS-dependent necroptotic cell death due to ATP depletion through mitochondrial dysfunction. This study provides us a possible mechanism underlying why apigenin could be used as a therapeutic candidate for treating malignant mesothelioma.

The efficacy of bleomycin for treating keloid and hypertrophic scar: A systematic review and meta-analysis.

BACKGROUND: Pathologic scars can lead to itching, erythema, and psychological stress due to cosmetic problems. Bleomycin, one of anticancer agents, has been used for treating keloid or hypertrophic scar. Some studies have shown that bleomycin can induce markedly scar improvement. AIMS: To evaluate the efficacy of bleomycin compared to corticosteroid as well as other treatments for keloid or hypertrophic scar using meta-analysis methods. METHODS: A computerized search was performed in different databases including Cochrane, Embase, and PubMed. Three randomized controlled trials (RCTs) and two controlled clinical trials (CCTs) were included. Then, statistical analyses of extracted outcome data from the studies were calculated using Rex (version 3.0.1; RexSoft Inc). RESULTS: Scar improvement was significantly increased in the bleomycin group compared to the triamcinolone acetonide (TAC) group (SMD: 0.59, 95% CI: 0.30-0.88, P < .0001). In addition, there was also statistically significant difference between the bleomycin group and the 5-FU group (SMD: 1.37, 95% CI: 0.88-1.85, P < .0001). Bleomycin increased relatively scar improvement compared to TAC combined with 5-FU, although there was no statistical difference (SMD: 0.63, 95% CI: -0.59-1.84, P = .3108). Furthermore, bleomycin demonstrated significantly increased improvement of scar compared to TAC combined with cryotherapy (SMD: 1.11, 95% CI: 0.48-1.74, P = .0006). CONCLUSIONS: This meta-analysis found that bleomycin was more effective for treating keloid or hypertrophic scar than other treatments including TAC, 5-FU, TAC combined with 5-FU, and TAC combined with cryotherapy. However, further comprehensive studies, including randomized controlled trials, are needed to perform objective analysis.

Overexpression of Nrf2 promotes colon cancer progression via ERK and AKT signaling pathways.

PURPOSE: We investigated the expression of Nrf2 in colorectal cancer and its correlation with clinicopathological characteristics as well as mechanisms and roles of Nrf2 expression including cell signaling pathway, survival, proliferation, and migration. METHODS: Nrf2 expression was measured in 12 and 30 different colorectal cancer (CRC) tissues by western blot (WB) and immunohistochemistry (IHC), respectively. SW480 cells were used for cell proliferation and cell migration tests. The correlation between the expression of Nrf2 and clinicopathologic parameters were evaluated using the chi-square or Fisher exact test. Data are expressed as the mean ± standard deviation for 3 independent experiments. P < 0.05 was considered statistically significant. RESULTS: Analysis of WB demonstrated that Nrf2 proteins were increased in CRC tissues, and decreased in normal tissues. IHC staining showed that the Nrf2 expression was elevated in CRC tissues, compared to matched normal tissues. When SW480 cells were suppressed with small interfering RNA of Nrf2, cell viability was inhibited, and cell apoptosis was increased. These results were found along with suppression of the phosphorylated form of extracellular signal-regulated kinase 1/2 and AKT. CONCLUSION: This study suggests that overexpression of Nrf2 may be related to carcinogenesis and progression of CRC.

Scleromyxedema with multiple systemic involvement: Successful treatment with intravenous immunoglobulin.

Scleromyxedema is a rare connective tissue disorder characterized by a generalized lichenoid eruption and sclerodermoid induration with histologic features of dermal mucin deposition. A 44-year-old man presented with a 3-year history of generalized progressive skin thickening and sclerosis. He had diffuse skin-colored to erythematous firm papules coalescing into indurated plaques over his whole body. He had been diagnosed with scleromyxedema from a skin biopsy with monoclonal gammopathy of undetermined significance (MGUS) at another tertiary hospital 3 years earlier. He had been treated with systemic corticosteroids and methotrexate, but his systemic symptoms (dyspnea, dysphagia, skin swelling, and induration) had worsened over the past year, so he visited our clinic seeking further evaluation and management. The patient received high-dose intravenous immunoglobulin (IVIG) therapy once a month in combination with systemic corticosteroids. After three courses of IVIG, his cutaneous symptoms and dyspnea had improved dramatically. Herein we report a case of scleromyxedema with systemic involvement with significant improvement following IVIG therapy.

Arctigenin induces necroptosis through mitochondrial dysfunction with CCN1 upregulation in prostate cancer cells under lactic acidosis.

Arctigenin, a mitochondrial complex I inhibitor, has been identified as a potential anti-tumor agent, but the involved mechanism still remains elusive. Herein, we studied the underlying mechanism(s) of action of arctigenin on acidity-tolerant prostate cancer PC-3AcT cells in the lactic acid-containing medium. At concentration showing no toxicity on normal prostate epithelial RWPE-1 and HPrEC cells, arctigenin alone or in combination with docetaxel induced significant cytotoxicity in PC-3AcT cells compared to parental PC-3 cells. With arctigenin treatment, reactive oxygen species (ROS) levels, annexin V-PE positive fractions, sub-G0/G1 peak in cell cycle analysis, mitochondrial membrane depolarization, and cell communication network factor 1 (CCN1) levels were increased, while cellular ATP content and phospho (p)-Akt level were decreased. Pretreatment with ROS scavenger N-acetylcysteine effectively reversed the series of phenomena caused by arctigenin, suggesting that ROS served as upstream molecules of arctigenin-driven cytotoxicity. Meanwhile, arctigenin increased the levels of p-receptor-interacting serine/threonine-protein kinase 3 (p-RIP3) and p-mixed lineage kinase domain-like pseudokinase (p-MLKL) as necroptosis mediators, and pretreatment with necroptosis inhibitor necrostatin-1 restored their levels and cell viability. Treatment of spheroids with arctigenin resulted in necroptotic cell death, which was prevented by N-acetylcysteine. The siRNA-based knockdown of CCN1 suppressed the levels of MLKL, B-cell lymphoma 2 (Bcl-2), and induced myeloid leukemia cell differentiation (Mcl-1) with increased cleavage of Bcl-2-associated X (Bax) and caspase-3. Collectively, these results provide new insights into the molecular mechanisms underlying arctigenin-induced cytotoxicity, and support arctigenin as a potential therapeutic agent for targeting non-Warburg phenotype through induction of necroptosis via ROS-mediated mitochondrial damage and CCN1 upregulation.

Pifithrin-µ induces necroptosis through oxidative mitochondrial damage but accompanies epithelial-mesenchymal transition-like phenomenon in malignant mesothelioma cells under lactic acidosis.

Heat shock protein 70 (HSP70), a chaperone protein associated with tumorigenesis and chemoresistance, has attracted significant attention as a potential therapeutic target for the development of anticancer drugs. Here, the effects of pifithrin-µ, an effective dual inhibitor of HSP70 and p53, on anticancer activities and epithelial-mesenchymal transition (EMT) were investigated in malignant mesothelioma (MM) cells. MSTO-211HAcT cells, pre-incubated in a medium containing lactic acid, showed more potent resistance to cisplatin and gemcitabine, compared with their acid-sensitive parental MSTO-211H cells. Pifithrin-µ treatment induced both apoptosis and necroptosis, which were accompanied by an EMT-like phenomenon, as evidenced by an elongated cell morphology, decreased levels of epithelial cell markers including E-cadherin, claudin-1, and ß-catenin, increased levels of mesenchymal markers including Snail, Slug, and vimentin, and increased cell migratory property. Moreover, pifithrin-µ increased intracellular ROS levels, which is associated with mitochondrial dysfunction and decreased cellular ATP content. A series of changes caused by pifithrin-µ treatment were effectively restored by lowering the ROS level through pretreatment with N-acetylcysteine. Collectively, our results suggest that pifithrin-µ may promote the metastatic behavior of surviving cells by triggering the EMT, despite its effective cell-killing action against MM cells, possibly linked to oxidative mitochondrial dysfunction and ATP depletion.

Flavonoid morin inhibits proliferation and induces apoptosis of melanoma cells by regulating reactive oxygen species, Sp1 and Mcl-1.

Reactive oxygen species (ROS) is associated with cancer progression in different cancers, including melanoma. It also affects specificity protein (Sp1), a transcription factor. Flavonoid morin is known to inhibit growth of cancer cells, including lung cancer and breast cancer. Herein, we hypothesized that morin can inhibit cancer activities in melanoma by altering ROS generation. The aim of this study is to determine the effects of morin and its underlying mechanisms in melanoma cells. Effects of morin on cell proliferation and apoptosis were determined using standardized assays. Changes in pro-apoptotic and anti-apoptotic proteins were analyzed by western blot analysis. Cellular ROS levels and mitochondrial function were evaluated by measuring DCF-DA fluorescence and rhodamine-123 fluorescence intensities, respectively. Morin induced ROS production and apoptosis, as presented by increased proportion of cells with Annexin V-PE(+) staining and sub-G0/G1 peak in cell cycle analysis. It also downregulated Sp1, Mcl-1, Bcl-2, and caspase-3 but upregulated cleaved caspase-3, Bax, and PUMA. In immunohistochemical staining, Sp1 was overexpressed in melanoma tissues compared to normal skin tissues. Collectively, our data suggest that morin can induce apoptosis of melanoma cells by regulating pro-apoptotic and anti-apoptotic proteins through ROS, and may be a potential substance for treatment of melanoma.

Cariporide Enhances the DNA Damage and Apoptosis in Acid-tolerable Malignant Mesothelioma H-2452 Cells.

The Na+/H+ exchanger is responsible for maintaining the acidic tumor microenvironment through its promotion of the reabsorption of extracellular Na+ and the extrusion of intracellular H+. The resultant increase in the extracellular acidity contributes to the chemoresistance of malignant tumors. In this study, the chemosensitizing effects of cariporide, a potent Na+/H+-exchange inhibitor, were evaluated in human malignant mesothelioma H-2452 cells preadapted with lactic acid. A higher basal level of phosphorylated (p)-AKT protein was found in the acid-tolerable H-2452AcT cells compared with their parental acid-sensitive H-2452 cells. When introduced in H-2452AcT cells with a concentration that shows only a slight toxicity in H-2452 cells, cariporide exhibited growth-suppressive and apoptosis-promoting activities, as demonstrated by an increase in the cells with pyknotic and fragmented nuclei, annexin V-PE(+) staining, a sub-G0/G1 peak, and a G2/M phase-transition delay in the cell cycle. Preceding these changes, a cariporide-induced p-AKT down-regulation, a p53 up-regulation, an ROS accumulation, and the depolarization of the mitochondrial-membrane potential were observed. A pretreatment with the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 markedly augmented the DNA damage caused by the cariporide, as indicated by a much greater extent of comet tails and a tail moment with increased levels of the p-histone H2A.X, p-ATMSer1981, p-ATRSer428, p-CHK1Ser345, and p-CHK2Thr68, as well as a series of pro-apoptotic events. The data suggest that an inhibition of the PI3K/AKT signaling is necessary to enhance the cytotoxicity toward the acid-tolerable H-2452AcT cells, and it underlines the significance of proton-pump targeting as a potential therapeutic strategy to overcome the acidic-microenvironment-associated chemotherapeutic resistance.

Cisplatin and resveratrol induce apoptosis and autophagy following oxidative stress in malignant mesothelioma cells.

Malignant mesothelioma (MM) is characterized by poor responsiveness to current chemotherapeutic drugs, usually owing to high resistance to apoptosis. Here, we investigated chemosensitizing effects of phytochemical resveratrol, in combination with cisplatin, on MM cells. The combination treatment of cisplatin and resveratrol (CDDP/RSV) synergistically induced apoptosis, as evidenced by typical cell morphological changes, the appearance of sub-G0/G1 peak, an increase in the Annexin V(+) cells and the cleavage of caspase-3 and PARP. CDDP/RSV increased ROS production and depolarization of mitochondrial membrane potential with an increase in the Bax/Bcl-2 ratio. These changes were attenuated by pretreatment with N-acetylcysteine, suggesting that CDDP/RSV induced apoptosis through oxidative mitochondrial damage. Compared with MSTO-211H cells, CDDP/RSV was less efficient in killing H-2452 cells. H-2452 cells exhibited an enhanced autophagy to CDDP/RSV, as observed by an increase in viable cells exhibiting intense LysoTracker Red staining and up-regulation of Beclin-1 and LC3A. Inhibition of autophagy by bafilomycin A1 rendered cells more sensitive to CDDP/RSV-induced cytotoxicity and this was associated with induction of apoptosis. These data indicate that the increased resistance of H-2452 cells to CDDP/RSV is closely related to the activation of self-defensive autophagy, and provide the rationale for targeting the autophagy regulation in the treatment of MM.

Nickel(II)-induced nasal epithelial toxicity and oxidative mitochondrial damage.

In probing the underlying mechanisms of nickel(II)-induced cytotoxicity on nasal epithelium, we investigated the effects of nickel(II) acetate on nasal epithelial RPMI-2650 cells. Nickel(II) elicited apoptosis, as signified by pyknotic and fragmented nuclei, increased caspase-3/7 activity, and an increase in annexin V binding, hypodiploid DNA, and Bax/Bcl-2 protein ratio. Nickel(II)-induced G2/M arrest was associated with up-regulation of p21(WAF1/CIP1) expression, decrease in phosphorylation at Thr(161) of Cdc2, and down-regulation of cyclin B1. Associated with these responses, ROS generation and mitochondrial depolarization increased in a nickel(II) concentration-dependent fashion. Pretreatment with N-acetylcysteine (NAC) attenuated these changes. p53 reporter gene assay and analyses of p53, Puma, Bax, and Bcl-2 protein levels indicated that NAC inhibited nickel(II)-induced activation of p53-mediated mitochondrial apoptotic pathway. Collectively, our study provides evidences that nickel(II) may induce oxidative damage on nasal epithelium in which antioxidant NAC protects cells against nickel(II)-induced apoptosis through the prevention of oxidative stress-mediated mitochondrial damage.

Dermal fibroblast expression of stromal cell-derived factor-1 (SDF-1) promotes epidermal keratinocyte proliferation in normal and diseased skin.

Stromal cells provide a crucial microenvironment for overlying epithelium. Here we investigated the expression and function of a stromal cell-specific protein, stromal cell-derived factor-1 (SDF-1), in normal human skin and in the tissues of diseased skin. Immunohistology and laser capture microdissection (LCM)-coupled quantitative real-time RT-PCR revealed that SDF-1 is constitutively and predominantly expressed in dermal stromal cells in normal human skin in vivo. To our surprise, an extremely high level of SDF-1 transcription was observed in the dermis of normal human skin in vivo, evidenced by much higher mRNA expression level than type I collagen, the most abundant and highly expressed protein in human skin. SDF-1 was also upregulated in the tissues of many human skin disorders including psoriasis, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC). Double immunostaining for SDF-1 and HSP47 (heat shock protein 47), a marker of fibroblasts, revealed that fibroblasts were the major source of stroma-cell-derived SDF-1 in both normal and diseased skin. Functionally, SDF-1 activates the ERK (extracellular-signal-regulated kinases) pathway and functions as a mitogen to stimulate epidermal keratinocyte proliferation. Both overexpression of SDF-1 in dermal fibroblasts and treatment with rhSDF-1 to the skin equivalent cultures significantly increased the number of keratinocyte layers and epidermal thickness. Conversely, the stimulative function of SDF-1 on keratinocyte proliferation was nearly completely eliminated by interfering with CXCR4, a specific receptor of SDF-1, or by knock-down of SDF-1 in fibroblasts. Our data reveal that extremely high levels of SDF-1 provide a crucial microenvironment for epidermal keratinocyte proliferation in both physiologic and pathologic skin conditions.