Selenium and Arsenic Levels, Prevalence of Common Variants of Genes Involved in Their Metabolism, and Psoriasis Disease

Using an Inductively Coupled Plasma Mass Spectrometer we measured the concentration of selenium and arsenic in serum and blood samples from 336 unselected psoriatic patients and 336 matched healthy controls to evaluate any associations with the clinical course of the disease. We genotyped 336 patients and 903 matched controls to evaluate the prevalence of SOD2 (rs4880), CAT (rs1001179), GPX1 (rs1050450), and DMGDH (rs921943) polymorphisms using Taqman assays. The mean selenium (Se) level in serum was 74 µg/L in patients and 86 µg/L in controls (p < 0.001). The mean Se level in blood was 95 µg/L in patients and 111 µg/L in controls (p < 0.001). Psoriasis risk was greatest among participants with the lowest serum (<68.75 µg/L, OR: 8.30; p < 0.001) and lowest blood concentrations of Se (<88.04 µg/L, OR: 10.3; p < 0.001). Similar results were observed in subgroups of males and females. We found an inverse correlation of selenium levels with PASI, NAPSI, and BSA scores. There was no significant difference in the distribution of the CAT, GPX1, DMGDH, and SOD2 polymorphisms. Among carriers of rs4880, rs1001179, and rs921943 polymorphisms, blood selenium levels were significantly lower. The mean arsenic level in serum was 0.79 µg/L in patients and 0.7 µg/L in controls (p = 0.2). The mean concentration in blood was 1.1 µg/L in patients and 1.3 µg/L in controls (p < 0.001). In conclusion, we found that lower selenium levels, in blood and serum, are associated with psoriasis risk and its more severe course. Future prospective studies should focus on the optimalisation of the concentration of this trace element not only for prophylactic guidance but also to support the treatment of this disease.

Exploring the Effect of Xiao-Chai-Hu Decoction on Treating Psoriasis Based on Network Pharmacology and Experiment Validation

BACKGROUND

Psoriasis is a chronic, inflammatory and recurrent skin disease. Xiao-Chai-Hu Decoction (XCHD) has shown good effects against some inflammatory diseases and cancers. However, the pharmacological effect and mechanisms of XCHD on psoriasis are not yet clear.

OBJECTIVE

To uncover the effect and mechanisms of XCHD on psoriasis by integrating network pharmacology, molecular docking, and in vivo experiments.

METHODS

The active ingredients and corresponding targets of XCHD were screened through Traditional Chinese Medicine Systems Pharmacology Database and Analysis (TCMSP) and Traditional Chinese Medicine Integrated Database (TCMID). Differentially expressed genes (DEGs) of psoriasis were obtained from the gene expression omnibus (GEO) database. The XCHD-psoriasis intersection targets were obtained by intersecting XCHD targets, and DEGs were used to establish the "herb-active ingredient-target" network and Protein-Protein Interaction (PPI) Network. The hub targets were identified based on the PPI network by Cytoscape software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed next. Molecular docking was executed via AutoDockTools-1.5.6. Finally, in vivo experiments were carried out further to validate the therapeutic effects of XCHD on psoriasis.

RESULTS

58 active components and 219 targets of XCHD were screened. 4 top-active components (quercetin, baicalein, wogonin and kaempferol) and 7 hub targets (IL1B, CXCL8, CCND1, FOS, MMP9, STAT1 and CCL2) were identified. GO and KEGG pathway enrichment analyses indicated that the TNF signaling pathway, IL-17 signaling pathway and several pathways were involved. Molecular docking results indicated that hub genes had a good affinity to the corresponding key compounds. In imiquimod (IMQ)-induced psoriasis mouse models, XCHD could significantly improve psoriasis-like skin lesions, downregulate KRT17 and Ki67, and inhibit inflammation cytokines and VEGF.

CONCLUSION

XCHD showed the therapeutic effect on psoriasis by regulating keratinocyte differentiation, and suppressing inflammation and angiogenesis, which provided a theoretical basis for further experiments and clinical research.

CHAC1 exacerbates arsenite cytotoxicity by lowering intracellular glutathione levels

We here examined whether CHAC1 is implicated in arsenite (As(III))-induced cytotoxicity in HaCaT cells. We found that HaCaT cells in which the intracellular GSH levels were elevated by transfection with CHAC1 siRNA showed decreased sensitivity to As(III) compared to the control cells. Treatment with BSO (an inhibitor of GSH biosynthesis) abolished the decrease in sensitivity to As(III), suggesting that an increase in intracellular GSH levels was involved in the decrease in sensitivity to As(III) due to the decrease in the levels of CHAC1 expression. When we examined the expression of CHAC1 after exposure of HaCaT cells to As(III), the levels of CHAC1 were increased. Since CHAC1 is a proapoptotic factor, we examined appearance of apoptotic cells and cleavage of caspase-3 after exposure to As(III) to determine whether As(III)-induced CHAC1 up-regulation was involved in apoptosis induction. The results showed that induction of apoptosis by As(III) exposure was not detected in CHAC1 siRNA-transfected cells. Together, our findings indicate that CHAC1 is involved in the sensitivity of HaCaT cells to As(III) by regulating the intracellular GSH levels, and in particular, CHAC1 is involved in As(III)-induced apoptosis.

Relationship between Immune Cells, Depression, Stress, and Psoriasis: Could the Use of Natural Products Be Helpful?

Psoriasis is one of the most widespread chronic inflammatory skin diseases, affecting about 2%-3% of the worldwide adult population. The pathogenesis of this disease is quite complex, but an interaction between genetic and environmental factors has been recognized with an essential modulation of inflammatory and immune responses in affected patients. Psoriatic plaques generally represent the clinical psoriatic feature resulting from an abnormal proliferation and differentiation of keratinocytes, which cause dermal hyperplasia, skin infiltration of immune cells, and increased capillarity. Some scientific pieces of evidence have reported that psychological stress may play a key role in psoriasis, and the disease itself may cause stress conditions in patients, thus reproducing a vicious cycle. The present review aims at examining immune cell involvement in psoriasis and the relationship of depression and stress in its pathogenesis and development. In addition, this review contains a focus on the possible use of natural products, thus pointing out their mechanism of action in order to counteract clinical and psychological symptoms.

Influence of a combination of triptolide and ferulic acid on the activities of CYP450 enzymes and oxidative stress in HaCaT cells

Topical administration of triptolide (TP) is effective in the treatment of rheumatoid arthritis (RA), but it can also induce skin irritation. Previous studies have used data mining strategies to analyze the application of Tripterygium wilfordii in the treatment of RA and have shown that TP and ferulic acid (FA) can be used in combination due to their component compatibility. The aims of the present study were to investigate the mechanisms underlying the effects of TP treatment and to identify its effects on metabolism and oxidative damage in the skin. MTT assay results suggested that the HaCaT cell survival rate was significantly increased when the compatibility ratio of TP to FA was 1:100. Moreover, the combination of TP with FA (TP + FA) did not significantly affect the activities of the cytochrome P40 (CYP) enzymes CYP family 1 subfamily A member 2 (CYP1A2), CYP2E1 and CYP3A4, when used as a 'cocktail'. It was found that TP + FA significantly decreased the production levels of reactive oxygen species (ROS), superoxide dismutase and malondialdehyde in HaCaT cells, while significantly increasing levels of glutathione and catalase. In addition, TP + FA significantly increased nuclear factor erythroid 2-related factor 2 protein expression, compared with TP alone. Thus, the present results indicated that the underlying mechanism of TP + FA efficacy may be related to decreased ROS production level in HaCaT cells, increased production levels of key antioxidant factors and increased antioxidant activity of the epidermis, all of which were correlated with a protective effect against oxidative damage.

Quercetin Loaded Nanoparticles in Targeting Cancer: Recent Development

The spread of metastatic cancer cell is the main cause of death worldwide. Cellular and molecular basis of the action of phytochemicals in the modulation of metastatic cancer highlights the importance of fruits and vegetables. Quercetin is a natural bioflavonoid present in fruits, vegetables, seeds, berries, and tea. The cancer-preventive activity of quercetin is well documented due to its anti-inflammatory, anti-proliferative and anti-angiogenic activities. However, poor water solubility and delivery, chemical instability, short half-life, and low-bioavailability of quercetin limit its clinical application in cancer chemoprevention. A better understanding of the molecular mechanism of controlled and regulated drug delivery is essential for the development of novel and effective therapies. To overcome the limitations of accessibility by quercetin, it can be delivered as nanoconjugated quercetin. Nanoconjugated quercetin has attracted much attention due to its controlled drug release, long retention in tumor, enhanced anticancer potential, and promising clinical application. The pharmacological effect of quercetin conjugated nanoparticles typically depends on drug carriers used such as liposomes, silver nanoparticles, silica nanoparticles, PLGA (Poly lactic-co-glycolic acid), PLA (poly(D,L-lactic acid)) nanoparticles, polymeric micelles, chitosan nanoparticles, etc. In this review, we described various delivery systems of nanoconjugated quercetin like liposomes, silver nanoparticles, PLGA (Poly lactic-co-glycolic acid), and polymeric micelles including DOX conjugated micelles, metal conjugated micelles, nucleic acid conjugated micelles, and antibody-conjugated micelles on in vitro and in vivo tumor models; as well as validated their potential as promising onco-therapeutic agents in light of recent updates.

Effects of medicinal waters on the UV-sensitivity of human keratinocytes - a comparative pilot study

Balneotherapy has been used to treat several diseases including locomotor, neurological and dermatological conditions. The basis of the "organic hypothesis" of medical balneology is that medicinal waters, especially thermal spa and hot spring waters, contain a high variability of organic components with possible biological effects, including UV photo-protection. The recent study aims to clarify this effect in a human keratinocyte cell line model. Results confirm that organic-rich extract of selected medicinal waters might protect skin-derived cells from DNA damage. These results give a clinical relevance to medicinal waters or pharmaceutical products prepared from them in preventing the adverse effects of solar or artificial UV radiation on the human skin.

Alternating consumption of β-glucan and quercetin reduces mortality in mice with colorectal cancer

The current dietary recommendations for disease prevention and management are scarce and are not well supported. Beta-glucan or quercetin in a diet can alleviate colorectal cancer (CRC) by regulating the gut microbiota and related genes, but the effects of alternating their consumption for routine ingestion during CRC occurrence remain unknown. This study investigated the effects of alternating the consumption of β-glucan and quercetin for routine ingestion on CRC development in mice. The mortality rate, colonic length, inflammatory cytokines, gut microbiota, and colonic epithelial gene expression in healthy and CRC mice that consumed normal and alternate diets were compared and studied. The results showed that alternating the consumption of β-glucan and quercetin (alternating among a β-glucan diet, a normal diet and a normal diet that was supplemented with quercetin) alleviated colon damage and reduced the mortality rate in CRC mice, with a reduction in mortality of 12.5%. Alternating the consumption of β-glucan and quercetin significantly decreased the TNF-α level, increased the relative abundance of Parabacteroides, and downregulated three genes (Hmgcs2, Fabp2, and Gpt) that are associated with inflammation and cancer. Alternating the consumption of some bioactive compounds, such as β-glucan and quercetin, in food can contribute to human health. This experiment provided some experimental evidence for the dietary recommendations for disease prevention and management.

Erianin Inhibits Proliferation and Induces Apoptosis of HaCaT Cells via ROS-Mediated JNK/c-Jun and AKT/mTOR Signaling Pathways

Psoriasis is a recurrent skin disease described as keratinocyte hyperproliferation and aberrant differentiation. Erianin, a bibenzyl compound extracted from Dendrobium chrysotoxum, has displayed antitumor and anti-angiogenesis effects. However, the effects of erianin on a human keratinocyte cell line (HaCaT) are not fully understood. In the present study, we explored the effect of erianin on proliferation and apoptosis in HaCaT cells. Our results indicated that treatment with erianin ranging from 12.5 nM to 50 nM inhibited proliferation and induced apoptosis of HaCaT cells. In addition, erianin-induced apoptosis was accompanied by elevated reactive oxygen species (ROS). The ROS scavenger N-acetyl-cysteine (NAC) attenuated this elevation. Moreover, treatment with erianin induced activation of the c-Jun N-terminal kinase (JNK)/c-Jun signaling pathway and suppressed the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, while pretreatment with NAC also reversed these effects. Collectively, these data demonstrated that erianin inhibited proliferation and induced apoptosis of HaCaT cells through ROS-mediated JNK/c-Jun and AKT/mTOR signaling pathways. Erianin could be recognized as a potential anti-psoriasis drug.

Apoptotic or Antiproliferative Activity of Natural Products against Keratinocytes for the Treatment of Psoriasis

Natural products or herbs can be used as an effective therapy for treating psoriasis, an autoimmune skin disease that involves keratinocyte overproliferation. It has been demonstrated that phytomedicine, which is used for psoriasis patients, provides some advantages, including natural sources, a lower risk of adverse effects, and the avoidance of dissatisfaction with conventional therapy. The herbal products’ structural diversity and multiple mechanisms of action have enabled the synergistic activity to mitigate psoriasis. In recent years, the concept of using natural products as antiproliferative agents in psoriasis treatment has attracted increasing attention in basic and clinical investigations. This review highlights the development of an apoptotic or antiproliferatic strategy for natural-product management in the treatment of psoriasis. We systematically introduce the concepts and molecular mechanisms of keratinocyte-proliferation inhibition by crude extracts or natural compounds that were isolated from natural resources, especially plants. Most of these studies focus on evaluation through an in vitro keratinocyte model and an in vivo psoriasis-like animal model. Topical delivery is the major route for the in vivo or clinical administration of these natural products. The potential use of antiproliferative phytomedicine on hyperproliferative keratinocytes suggests a way forward for generating advances in the field of psoriasis therapy.

Fisetin and Quercetin: Promising Flavonoids with Chemopreventive Potential

Despite advancements in healthcare facilities for diagnosis and treatment, cancer remains the leading cause of death worldwide. As prevention is always better than cure, efficient strategies are needed in order to deal with the menace of cancer. The use of phytochemicals as adjuvant chemotherapeutic agents in heterogeneous human carcinomas like breast, colon, lung, ovary, and prostate cancers has shown an upward trend during the last decade or so. Flavonoids are well-known products of plant derivatives that are reportedly documented to be therapeutically active phytochemicals against many diseases encompassing malignancies, inflammatory disorders (cardiovascular disease, neurodegenerative disorder), and oxidative stress. The current review focuses on two key flavonols, fisetin and quercetin, known for their potential pharmacological relevance. Also, efforts have been made to bring together most of the concrete studies pertaining to the bioactive potential of fisetin and quercetin, especially in the modulation of a range of cancer signaling pathways. Further emphasis has also been made to highlight the molecular action of quercetin and fisetin so that one could explore cancer initiation pathways and progression, which could be helpful in designing effective treatment strategies.

Rutin and ascorbic acid cooperation in antioxidant and antiapoptotic effect on human skin keratinocytes and fibroblasts exposed to UVA and UVB radiation

The combination of ascorbic acid and rutin is frequently used in oral preparations. However, despite numerous protective effects of each component individually, their combined effect on ultraviolet (UV)-irradiated skin cells has never been evaluated. The aim of this study was to evaluate the combined effect of ascorbic acid and rutin on human keratinocytes and fibroblasts exposed to UVA and UVB radiation. Skin keratinocytes and fibroblasts exposed to UVA and UVB radiation were treated with ascorbic acid or/and rutin. The total antioxidant properties of both components, as well as their effect on cellular pro- and antioxidant status, lipid and protein oxidation, transmembrane transport, and pro-inflammatory and pro/antiapoptotic protein expression were measured. The combination of ascorbic acid and rutin had higher antioxidant properties compared to the activity of the single compound alone, and showed a stronger effect against UV-induced reactive oxygen species generation. The ascorbic acid and rutin combination also showed increased antioxidant enzyme activity (catalase, superoxide dismutase, thioredoxin reductase), which was impaired following UV irradiation. Moreover, ascorbic acid additional stimulated UV-induced bilitranslocase activity responsible for rutin transport, and therefore favored rutin effect on Nrf2 pathway, simultaneously differentiating the reaction of keratinocytes and fibroblasts. In keratinocytes, Nrf2 is strongly activated, while in fibroblasts decreased Nrf2 activity was observed. Used mixture, also significantly silenced UV-induced expression of pro-inflammatory factor NFκB and pro-apoptotic proteins such as caspases 3, 8, and 9. These results showed that ascorbic acid and rutin are complementary in their antioxidant actions, transport and signaling functions. Their combined antioxidant, antiinflammatory and antiapoptotic actions suggest rutin and ascorbic acid are a potentially cytoprotective team against UV-induced skin damage.

Juglans regia L. protects against UVB induced apoptosis in human epidermal keratinocytes

The present study was aimed to investigate the photoprotective effect of the male flower of J. regia L. (MEJR) against ultraviolet-B induced apoptosis in human skin cells. Human skin epidermal keratinocytes were pretreated with the MEJR (80 µg/ml, has been selected after MTT assay), prior to 30 min UVB-irradiation at a dose of 20 mJ/cm². Mitochondrial membrane potential was evaluated using Rhodamine-123 staining; the % apoptosis by Hoechst staining and acridine orange staining; DNA damage was measured by comet assay. The levels of p53, Bax, Bcl-xL, Bcl-2, Cytochrome c, Caspase-9 and Caspase-3 expression in HaCaT cells were analyzed by western blotting and RT-PCR. Pretreatment with MEJR 80 µg/ml prior to UVB-irradiation significantly prevents apoptotic characteristics, DNA damage and loss of mitochondrial membrane potential. Thus, MEJR protects UVB-mediated human skin cells, by modulating the expression of apoptotic markers and UVB-induced DNA damage in HaCaT cells.

Skin delivery of epigallocatechin-3-gallate (EGCG) and hyaluronic acid loaded nano-transfersomes for antioxidant and anti-aging effects in UV radiation induced skin damage

The present work attempts to develop and statistically optimize transfersomes containing EGCG and hyaluronic acid to synergize the UV radiation-protective ability of both compounds, along with imparting antioxidant and anti-aging effects. Transfersomes were prepared by thin film hydration technique, using soy phosphatidylcholine and sodium cholate, combined with high-pressure homogenization. They were characterized with respect to size, polydispersity index, zeta potential, morphology, entrapment efficiency, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), in vitro antioxidant activity and ex vivo skin permeation studies. Cell viability, lipid peroxidation, intracellular ROS levels and expression of MMPs (2 and 9) were determined in human keratinocyte cell lines (HaCaT). The composition of the transfersomes was statistically optimized by Design of Experiments using Box–Behnken design with four factors at three levels. The optimized transfersome formulation showed vesicle size, polydispersity index and zeta potential of 101.2 ± 6.0 nm, 0.245 ± 0.069 and −44.8 ± 5.24 mV, respectively. FTIR and DSC showed no interaction between EGCG and the selected excipients. XRD results revealed no form conversion of EGCG in its transfersomal form. The optimized transfersomes were found to increase the cell viability and reduce the lipid peroxidation, intracellular ROS and expression of MMPs in HaCaT cells. The optimized transfersomal formulation of EGCG and HA exhibited considerably higher skin permeation and deposition of EGCG than that observed with plain EGCG. The results underline the potential application of the developed transfersomes in sunscreen cream/lotions for improvement of UV radiation-protection along with deriving antioxidant and anti-aging effects.

Inhibitory effect of quercetin on colorectal lung metastasis through inducing apoptosis, and suppression of metastatic ability

BACKGROUND

Quercetin is a major dietary flavonoid found in a various fruits, vegetables, and grains. Although the inhibitory effects of quercetin have previously been observed in several types of cancer cells, the anti-metastatic effect of quercetin on colorectal metastasis has not been determined.

PURPOSE

This study investigated whether quercetin exhibits inhibitory effect on colorectal lung metastasis.

STUDY DESIGN

The effects of quercetin on cell viability, mitogen-activated protein kinases (MAPKs) activation, migration, invasion, epithelial-mesenchymal transition (EMT) and lung metastasis were investigated.

METHODS

We investigated the effect of quercetin on metastatic colon cancer cells using WST assay, Annexin V assay, real-time RT-PCR, western blot analysis and gelatin zymography. The anti-metastatic effect of quercetin in vivo was confirmed in a colorectal lung metastasis model.

RESULTS

Quercetin inhibited the cell viability of colon 26 (CT26) and colon 38 (MC38) cells and induced apoptosis through the MAPKs pathway in CT26 cells. Expression of EMT markers, such as E-, N-cadherin, β-catenin, and snail, were regulated by non-toxic concentrations of quercetin. Moreover, the migration and invasion abilities of CT26 cells were inhibited by quercetin through expression of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) regulation. Quercetin markedly decreased lung metastasis of CT26 cells in an experimental in vivo metastasis model.

CONCLUSION

In conclusion, this study demonstrates for the first time that quercetin can inhibit the survival and metastatic ability of CT26 cells, and it can subsequently suppress colorectal lung metastasis in the mouse model. These results indicate that quercetin may be a potent therapeutic agent for the treatment of metastatic colorectal cancer.

Molecular mechanisms of action of quercetin in cancer: recent advances

In the last few decades, the scientific community has discovered an immense potential of natural compounds in the treatment of dreadful diseases such as cancer. Besides the availability of a variety of natural bioactive molecules, efficacious cancer therapy still needs to be developed. So, to design an efficacious cancer treatment strategy, it is essential to understand the interactions of natural molecules with their respective cellular targets. Quercetin (Quer) is a naturally occurring flavonol present in many commonly consumed food items. It governs numerous intracellular targets, including the proteins involved in apoptosis, cell cycle, detoxification, antioxidant replication, and angiogenesis. The weight of available synergistic studies vigorously fortifies the utilization of Quer as a chemoprevention drug. This extensive review covers various therapeutic interactions of Quer with their recognized cellular targets involved in cancer treatment.

Nilotinib reduced the viability of human ovarian cancer cells via mitochondria-dependent apoptosis, independent of JNK activation

Nilotinib (AMN) induces apoptosis in various cancer cells; however the effect of AMN on human ovarian cancer cells is still unclear. A reduction in cell viability associated with the occurrence of apoptotic characteristics was observed in human SKOV-3 ovarian cancer cells under AMN but not sorafenib (SORA) or imatinib (STI) stimulation. Activation of apoptotic pathway including increased caspase (Casp)-3 and poly(ADP-ribose) polymerase 1 (PARP1) protein cleavage by AMN was detected with disrupted mitochondrial membrane potential (MMP) accompanied by decreased Bcl-2 protein and increased cytosolic cytochrome (Cyt) c/cleaved Casp-9 protein expressions was found, and AMN-induced cell death was inhibited by peptidyl Casp inhibitors, VAD, DEVD and LEHD. Increased phosphorylated c-Jun N-terminal kinase (JNK) protein expression was detected in AMN- but not SORA- or STI-treated SKOV-3 cells, and the JNK inhibitors, SP600125 and JNKI, showed slight but significant enhancement of AMN-induced cell death in SKOV-3 cells. The intracellular peroxide level was elevated by AMN and H2O2, and N-acetylcysteine (NAC) prevented H2O2- but not AMN-induced peroxide production and apoptosis in SKOV-3 cells. AMN induction of apoptosis with increased intracellular peroxide production and JNK protein phosphorylation was also identified in human A2780 ovarian cancer cells, cisplatin-resistant A2780CP cells, and clear ES-2 cells. The evidence supporting AMN effectively reducing the viability of human ovarian cancer cells via mitochondrion-dependent apoptosis is provided.

Paeoniflorin inhibits human glioma cells via STAT3 degradation by the ubiquitin-proteasome pathway

We investigated the underlying mechanism for the potent proapoptotic effect of paeoniflorin (PF) on human glioma cells in vitro, focusing on signal transducer and activator of transcription 3 (STAT3) signaling. Significant time- and dose-dependent apoptosis and inhibition of proliferation were observed in PF-treated U87 and U251 glioma cells. Expression of STAT3, its active form phosphorylated STAT3 (p-STAT3), and several downstream molecules, including HIAP, Bcl-2, cyclin D1, and Survivin, were significantly downregulated upon PF treatment. Overexpression of STAT3 induced resistance to PF, suggesting that STAT3 was a critical target of PF. Interestingly, rapid downregulation of STAT3 was consistent with its accelerated degradation, but not with its dephosphorylation or transcriptional modulation. Using specific inhibitors, we demonstrated that the prodegradation effect of PF on STAT3 was mainly through the ubiquitin-proteasome pathway rather than via lysosomal degradation. These findings indicated that PF-induced growth suppression and apoptosis in human glioma cells through the proteasome-dependent degradation of STAT3.

The role of glycyrrhetinic acid modification on preparation and evaluation of quercetin-loaded chitosan-based self-aggregates

Quercetin (QC), a type of plant-based chemical, has been reported to own anticancer activity in vivo. However, the poor water solubility limits its pharmaceutical application. In this study, two kinds of QC-loaded self-aggregates based on O-carboxymethyl chitosan-cholic acid conjugates (CMCA) were developed to improve the drug bioavailability in which glycyrrhetinic acid (GA) modification was utilized in the nanocarrier fabrication (QC-GA-CMCA) or not (QC-CMCA). These self-aggregates were prepared by a modified ultrasound-dialysis method and the role of GA modification on the evaluation of QC-loaded self-aggregates was investigated. Transmission Electron Microscopy (TEM) images revealed the formation of spherical particles of both self-aggregates. Dynamic Light Scattering (DLS) analysis and UV-VIS spectroscopy showed that the QC-GA-CMCA had smaller size, narrower size distribution, higher drug loading and entrapment efficiency than corresponding QC-CMCA aggregates. QC-GA-CMCA showed more obvious sensitivity to acidic pH condition based on the zeta potential measurements at various pHs, and fastest drug release was observed at pH 5.7 for QC-CMCA while at pH 6.5 for QC-GA-CMCA. In addition, QC-GA-CMCA demonstrated enhanced cell cytotoxicity and higher cell apoptosis rate in vitro, and also higher AUC value and a prolonged residence time of drug in vivo.

Hydrogen peroxide/ATR-Chk2 activation mediates p53 protein stabilization and anti-cancer activity of cheliensisin A in human cancer cells

Cheliensisine A (Chel A) as a novel styryl-lactone isolated from Goniothalamus cheliensis Hu has been indicated to be a chemotherapeutic agent in Leukemia HL-60 cells. However, its potential for cancer treatment and the underlying mechanisms are not deeply investigated to the best of our knowledge. Current studies showed that Chel A could trigger p53-mediated apoptosis, accompanied with dramatically inhibition of anchorage-independent growth of human colon cancer HCT116 cells. Further studies found that Chel A treatment resulted in p53 protein stabilization and accumulation via the induction of its phosphorylation at Ser20 and Ser15. Moreover, Chel A-induced p53 protein accumulation and activation required ATR/Chk2 axis, which is distinct from the mechanism that we have most recently identified the Chk1/p53-dependent apoptotic response by Chel A in normal mouse epidermal Cl41 cells. In addition, our results demonstrated that hydrogen peroxide generation induced by Chel A acted as a precursor for all these signaling events and downstream biological effects. Taken together, we have identified the Chel A as a new therapeutic agent, which highlights its potential for cancer therapeutic effect.

Arsenic trioxide reactivates proteasome-dependent degradation of mutant p53 protein in cancer cells in part via enhanced expression of Pirh2 E3 ligase

The p53 gene is mutated in more than 50% of human tumors. Mutant p53 exerts an oncogenic function and is often highly expressed in cancer cells due to evasion of proteasome-dependent degradation. Thus, reactivating proteasome-dependent degradation of mutant p53 protein is an attractive strategy for cancer management. Previously, we found that arsenic trioxide (ATO), a drug for acute promyelocytic leukemia, degrades mutant p53 protein through a proteasome pathway. However, it remains unclear what is the E3 ligase that targets mutant p53 for degradation. In current study, we sought to identify an E3 ligase necessary for ATO-mediated degradation of mutant p53. We found that ATO induces expression of Pirh2 E3 ligase at the transcriptional level. We also found that knockdown of Pirh2 inhibits, whereas ectopic expression of Pirh2 enhances, ATO-induced degradation of mutant p53 protein. Furthermore, we found that Pirh2 E3 ligase physically interacts with and targets mutant p53 for polyubiquitination and subsequently proteasomal degradation. Interestingly, we found that ATO cooperates with HSP90 or HDAC inhibitor to promote mutant p53 degradation and growth suppression in tumor cells. Together, these data suggest that ATO promotes mutant p53 degradation in part via induction of the Pirh2-dependent proteasome pathway.

Additivity, antagonism, and synergy in arsenic trioxide-induced growth inhibition of C6 glioma cells: effects of genistein, quercetin and buthionine-sulfoximine

Arsenic trioxide (ATO) induces clinical remission in acute promyelocytic leukemia and growth inhibition in various cancer cell lines in vitro. Recently, genistein and quercetin were reported to potentiate ATO-provoked apoptosis in leukemia and hepatocellular carcinoma cells. Genistein acted via enhanced ROS generation and quercetin via glutathione depletion. Searching for potential strategies for the treatment of malignant gliomas in this study the capacity of these flavonoids to sensitize rat C6 astroglioma cells for the cytotoxic action of ATO was investigated. ATO inhibited cell growth in a concentration- and time-dependent manner. This effect was accompanied neither by enhanced radical generation nor lipid peroxidation and was not attributed to apoptosis. ATO treatment concentration-dependently increased glutathione levels. Genistein enhanced radical generation. Combined with ATO it inhibited cell growth additively. Additivity was also obtained after cotreatment with ATO and H2O2. Quercetin acted antagonistically on ATO-induced growth inhibition. Quercetin increased glutathione levels. In contrast, buthionine-sulfoximine (BSO) depleted cellular glutathione and acted synergistically with ATO. In conclusion, in C6 cells neither genistein nor quercetin are suited as sensitizing agent, in contrast to BSO. Depletion of cellular glutathione content rather than an increase of ROS generation plays a central role in the enhancement of ATO-toxicity in C6 cells.

Effects of ozone in normal human epidermal keratinocytes

Ozone is a tropospheric pollutant that can form at ground level as a result of an interaction between sunlight and hydrocarbon engine emissions. As ozone is an extremely oxidative reaction product, epidermal cells are in the outer layer of defense against ozone. We exposed normal human epidermal keratinocytes (NHEK) to concentrations of ozone that have been measured in cities and assayed for its effects. Hydrogen peroxide and IL-1α levels both increased while ATP levels decreased. We found a decrease in the NAD-dependent histone deacetylase, sirtuin 3. Lastly, we found that ozone increased DNA damage as evaluated by Comet assay. Taken together, our results show increased damage to NHEK that will ultimately impair normal cellular function as a result of an environmentally relevant ozone exposure.

Cheliensisin A inhibits EGF-induced cell transformation with stabilization of p53 protein via a hydrogen peroxide/Chk1-dependent axis

Cheliensisin A (Chel A), a novel styryl-lactone isolated from Goniothalamus cheliensis Hu, has been shown to induce apoptosis in human promyelocytic leukemia HL-60 cells with Bcl-2 downregulation. Yet, the potential chemopreventive effect of Chel A has not been explored. Here, we showed that Chel A treatment with various concentrations (0.5, 1.0, 2.0, and 4.0 μmol/L) for 3 weeks could dramatically inhibit EGF-induced cell transformation in Cl41 cells (IC50 ∼2.0 μmol/L). Also, coincubation of Cl41 cells with Chel A (2.0 and 4.0 μmol/L) for 48 hours could induce cell apoptosis in a caspase-3-dependent manner. Mechanically, Chel A treatment could result in increased p53 phosphorylation at Ser15 and elevated p53 total protein expression. Moreover, we found that p53 induction by Chel A was regulated at the protein degradation level, but not at either the transcription or the mRNA level. Further studies showed that p53 stabilization by Chel A was mediated via induction of phosphorylation and activation of Chk1 protein at Ser345. This notion was substantiated by the results that transfection of dominant negative mutant of Chk1 (GFP-Chk1 D130A) significantly attenuated the p53 protein expression, cell apoptosis, and inhibition of cell transformation by Chel A. Finally, increased hydrogen peroxide was found to mediate Chk1 phosphorylation at Ser345, p53 protein induction, cell apoptotic induction, and transformation inhibition following Chel A treatment. Taken together, our studies identify Chel A as a chemopreventive agent with the understanding of the molecular mechanisms involved.