GDU-952, a novel AhR agonist ameliorates skin barrier abnormalities and immune dysfunction in DNFB-induced atopic dermatitis in mice.

The aryl hydrocarbon receptor (AhR) is widely expressed in the skin. It controls immune-mediated skin responses to various external environmental signals, promote terminal differentiation of epidermal keratinocytes and participates the maintenance of the skin barrier function. As a therapeutic target, AhR activation modulates many diseases progression driven by immune/inflammatory processes such as atopic dermatitis (AD) and psoriasis. In this study, we revealed that GDU-952 is a novel AhR agonist, which is able to decreases IgE serum levels, to inhibit pro-inflammatory cytokines such as IL-6 and TNF-α and to induce immunoregulatory effects through restoring Th1/Th2 immune balance and promoting CD4+FOXP3+regulatory T (Treg) populations in AD skin lesions. Furthermore, GDU-952 can strengthen the skin barrier function through upregulating epidermal differentiation-related and tight junction proteins. This may alleviate AD symptoms, such as dermatitis scores, epidermal hyperplasia and mast cell infiltration. These results offer a rationale for further preclinical/clinical studies to evaluate the possible use of GDU-952 in the management of AD.

Design, synthesis and evaluation of novel pyrimidinylaminothiophene derivatives as FGFR1 inhibitors against human glioblastoma multiforme.

Vascular endothelial growth factor receptors (VEGFRs) have emerged as the most promising anti-angiogenic therapeutic targets for the treatment of recurrent glioblastomas (GBM). However, anti-VEGF treatments led to the high proportion of non-responder patients or non lasting clinical response and the tumor progression to the greater malignant stage. To overcome these problems, there is an utmost need to develop innovative anti-angiogenic therapies. In this study, we report the development of a series of new FGFR1 inhibitors. Among them, compound 4i was able to potently inhibit FGFR1 kinase activities both in vitro and in vivo. This compound displayed strong anti-angiogenic activity in HUVECs and anti-tumor growth and anti-invasion effects in U-87MG cell line. These results emphasize the importance of FGFR1-mediated signaling pathways in GBM and reveal that pharmacological inhibition of FGFR1 can enhance the anti-tumoral, anti-angiogenic and anti-metastatic efficiency against GBM. These data support targeting of FGFR1 as a novel anti-angiogenic strategy and highlight the potential of compound 4i as a promising anti-angiogenic and anti-metastatic candidate for GBM therapy.

Impact of polyphenols extracted from Tricholoma matsutake on UVB-induced photoaging in mouse skin.

BACKGROUND: Despite Tricholoma matsutake has been used as natural health products with multiple medicinal properties, detailed information about its polyphenolic composition as sources of anti-photoaging agents remains to be determined. OBJECTIVE: To investigate the impact of polyphenols extracted from Tricholoma matsutake (TME) on Ultraviolet B (UVB)-induced skin photoaging. MATERIALS AND METHODS: Various factors of oxidative stress and inflammation as well as histological and immunohistochemical analysis in the mouse dorsal skin were determined after UVB radiation. RESULTS: Topical administration with TME suppressed the UVB-induced skin thickness, wrinkles and erythema, and increased skin collagen content. Furthermore, TME decreased reactive oxygen species (ROS) level, upregulated glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), and glucose-6-phosphate dehydrogenase (G6PDH) activities and inhibited the expression of IL-1, IL-6, IL-8, and TNF-α in mice irradiated with UVB. TME could reduce UVB-induced p38 mitogen-activated protein kinase (p38 MAPK) phosphorylation and effectively inhibited the activity of the transcriptional factor nuclear factor-kappa B (NF-κB), thereby reducing the cyclooxygenase-2 (COX-2) expression, which is an important mediator of inflammatory cascade leading to the inflammatory response. CONCLUSION: Our data demonstrated that TME had various beneficial effects on UVB-induced skin photoaging due to its antioxidant and anti-inflammatory activities, and it might be exploited as a promising natural product in skin care, anti-photoaging and the therapeutic intervention of skin disorders related to both oxidative stress and inflammation.

Improvement of Skin Barrier Dysfunction by Phenolic-containing Extracts of Lycium barbarum via Nrf2/HO-1 Regulation.

Lycium barbarum have received an increasing popularity due to its powerful biological activity and medicinal use. However, the effect of Lycium barbarum on skin remains largely uncharacterized. The general purpose of this paper was to characterize the phenolic compounds in Lycium barbarum extract (LBE) using LC-HRMS/QTOF method and to investigate whether topical administration of LBE can repair skin barrier dysfunction in mice. Our data demonstrated that LBE could not only decrease ROS level and matrix metalloproteinase expression, but also strengthen intrinsic antioxidant defense system including SOD, GSH-Px and CAT, thereby resulting in increased skin collagen content and an improvement of UV-induced skin erythema, thickness and wrinkles. Improved skin barrier functions were highly correlated with increased expression of filaggrin, involucrin and loricrin as well as antioxidant proteins such as Nrf2 and HO-1 in UV-irradiated mice, suggesting that LBE may be promising natural products at a lower cost for the topical application in the treatment of skin diseases with defective barrier function.

Rapid and sensitive determination of four bisphosphonates in rat plasma after MTBSTFA derivatization using liquid chromatography-mass spectrometry.

Bisphosphonates (BPs) have broad medical applications against osteoporosis, bone metastasis and Paget's disease. The BP-related jaw osteonecrosis limits their use extensively and has a causal relationship with the process of drug disposition, such as deposition on bone and slow elimination rate. Thus it is imperative to accurately determine BP levels in either clinical or pharmacological/toxicological studies. The ability of trimethylsilyl diazomethane (TMSD) to alkylate the hydroxyls in phosphoric groups is an advantage in terms of decreasing polarity and enhancing mass response of BPs. There are, however, practical limitations to the cumbersome sample preparation procedure, the prolonged reaction time, the by-products and the obstacle to ionization. To overcome these disadvantages, a simplified and rapid precolumn derivatization method with N-(tert-Butyldimethylsilyl)-N-methyl-trifluoroacetamide (MTBSTFA) to quantify etidronate, clodronate, alendronate and zoledronate BPs in rat plasma was established in this work. The derivatization reaction was conducted within 2 min at room temperature, and the unitary di-tert-butyldimethylsilyl (di-tBDMS) derivative was obtained for each BP. Derivatives were separated on a XTerra® MS C8 column (2.1 × 50 mm, 3.5 µm) with the mobile phase of 5 mM ammonium acetate buffer (pH 8.5) and acetonitrile, then detected using electrospray ionization tandem mass spectrometry in negative mode. An easy extraction process instead of the time-consuming solid-phase extraction (SPE) was employed for plasma treatment. The proposed method showed good linearity for BPs over the range of 2-500 ng/mL in 20 µL plasma and high sensitivity owing to the larger molecular ions, higher ionization capacity and more stable fragments of di-tBDMS derivatives. The intra- and inter-batch precision were <13.1 %, and the accuracy ranged within ±10 %. The extraction recovery varied from 75.4 to 88.0 %. The optimized method was successfully applied to characterize the pharmacokinetic profile of zoledronate in rats. Moreover, it is a promising approach for the determination of other phosphoric acid-containing metabolites.

Synthesis and identification of quinoline derivatives as topoisomerase I inhibitors with potent antipsoriasis activity in an animal model.

Psoriasis is a chronic inflammatory and immune-mediated skin disease. Although certain agents have shown clinical success in treating psoriasis, development of safe and effective strategies for the treatment of this condition remains important. Research suggests that DNA topoisomerase I (Topo I) inhibitors may have potent psoriasis-ameliorating effects. Here, 25 quinoline derivatives were synthesized and identified as Topo I inhibitors. These compounds inhibited the 12-O-tetradecanoylphorbol-13-acetate-induced mouse ear inflammation. The most potent analogs, 5i and 5l, suppressed the expression of inflammatory cytokines in lipopolysaccharide-stimulated HaCaT cells. Additionally, the lead compounds significantly improved imiquimod-induced psoriasis-like inflammation in mice. Moreover, the expression levels of cytokines and inflammatory mediators, such as interleukin (IL)-17A, IL-22, IL-23, nuclear factor-κB subunit p65, tumor necrosis factor-α, and interferon-γ, were dramatically inhibited in the dorsal skin of 5i- and 5l-treated mice. These findings indicate that the inhibition of Topo I activity may potentially be an effective strategy for psoriasis treatment.

Aromatic-turmerone ameliorates imiquimod-induced psoriasis-like inflammation of BALB/c mice.

Psoriasis is a usual immune-mediated inflammatory skin disease with undefined pathogenesis. Aromatic-turmerone (ATM) is a mainly constituent of essential oil from Curcuma longa L. It has been shown to exhibit strong anti-oxidant, anti-tumor activities and anti-inflammatory effects. In this study, we investigated the effects of ATM on imiquimod (IMQ)-induced psoriasis-like BALB/c mice and its molecular mechanisms for anti-inflammatory effect. ATM showed inhibition of the transfer of CD8+ T cells in epidermis, and reduced expression of NF-κB and COX-2 as well as phosphorylation of p38 MAPK. It also decreased the level of TNF-α and IL-6, and down-regulates IL-17 IL-22 and IL-23 mRNA synthesis. Notably, we demonstrated that topically applied ATM alleviated skin inflammation in IMQ-induced mice. These results indicate that ATM, a natural active compound exhibits anti-inflammatory activity and is a promising candidate molecule to treat inflammatory skin diseases, such as psoriasis.

Use of curcumin in diagnosis, prevention, and treatment of Alzheimer's disease.

This review summarizes and describes the use of curcumin in diagnosis, prevention, and treatment of Alzheimer's disease. For diagnosis of Alzheimer's disease, amyloid-ß and highly phosphorylated tau protein are the major biomarkers. Curcumin was developed as an early diagnostic probe based on its natural fluorescence and high binding affinity to amyloid-ß. Because of its multi-target effects, curcumin has protective and preventive effects on many chronic diseases such as cerebrovascular disease, hypertension, and hyperlipidemia. For prevention and treatment of Alzheimer's disease, curcumin has been shown to effectively maintain the normal structure and function of cerebral vessels, mitochondria, and synapses, reduce risk factors for a variety of chronic diseases, and decrease the risk of Alzheimer's disease. The effect of curcumin on Alzheimer's disease involves multiple signaling pathways: anti-amyloid and metal iron chelating properties, antioxidation and anti-inflammatory activities. Indeed, there is a scientific basis for the rational application of curcumin in prevention and treatment of Alzheimer's disease.

Synthesis and biological evaluation of novel carbazole-rhodanine conjugates as topoisomerase II inhibitors.

In this study, a series of carbazole-rhodanine conjugates was synthesized and evaluated for their Topoisomerase II inhibition potency as well as cytotoxicity against a panel of four human cancer cell lines. Among these thirteen compounds, 3a, 3b, 3g, and 3h possessed Topoisomerase II inhibition potency at 20 µM. Mechanism study revealed that these compounds may function as Topo II catalytic inhibitors. It was found that the electron-withdrawing groups on the phenyl ring of compounds played an important role on enhancing both enzyme inhibition and cytotoxicity.

Synthesis of carbazole derivatives containing chalcone analogs as non-intercalative topoisomerase II catalytic inhibitors and apoptosis inducers.

Novel topoisomerase II (Topo II) inhibitors have gained considerable interest for the development of anticancer agents. In this study, a series of carbazole derivatives containing chalcone analogs (CDCAs) were synthesized and investigated for their Topo II inhibition and cytotoxic activities. The results from Topo II mediated DNA relaxation assay showed that CDCAs could significantly inhibit the activity of Topo II, and the structure-activity relationship indicated the halogen substituent in phenyl ring play an important role in the activity. Further mechanism studies revealed that CDCAs function as non-intercalative Topo II catalytic inhibitors. Moreover, some CDCAs showed micromolar cytotoxic activities. The most potent compound 3h exhibited notable growth inhibition against four human cancer cell lines. Flow cytometric analysis revealed that compounds 3d and 3h arrested the HL-60 cells in sub G1 phase by induction of apoptosis. It was further confirmed by Annexin-V-FITC binding assay. Western blot analysis revealed that compound 3h induces apoptosis likely through the activation of caspase proteins.

Aromatic-Turmerone Attenuates LPS-Induced Neuroinflammation and Consequent Memory Impairment by Targeting TLR4-Dependent Signaling Pathway.

SCOPE: Curcuma longa (turmeric) is a folk medicine in South and Southeast Asia, which has been widely used to alleviate chronic inflammation. Aromatic-turmerone is one of the main components abundant in turmeric essential oil. However, little information is available from controlled studies regarding its biological activities and underlying molecular mechanisms against chronic inflammation in the brain. In the current study, we employed a classical LPS model to study the effect and mechanism of aromatic-turmerone on neuroinflammation. METHODS AND RESULTS: The effects of aromatic-turmerone were studied in LPS-treated mice and BV2 cells. The cognitive function assays, protein analyses, and histological examination were performed. Oral administration of aromatic-turmerone could reverse LPS-induced memory disturbance and normalize glucose intake and metabolism in the brains of mice. Moreover, aromatic-turmerone significantly limited brain damage, through inhibiting the activation of microglia and generation of inflammatory cytokines. Further study in vitro revealed that aromatic-turmerone targeted Toll-like receptor 4 mediated downstream signaling, and lowered the release of inflammatory mediators. CONCLUSION: These observations indicate that aromatic-turmerone is effective in preventing brain damage caused by neuroinflammation and may be useful in the treatment of neuronal inflammatory diseases.

Curcumin Derivative Epigenetically Reactivates Nrf2 Antioxidative Stress Signaling in Mouse Prostate Cancer TRAMP C1 Cells.

The carcinogenesis of prostate cancer (PCa) in TRAMP model is highly correlated with hypermethylation in the promoter region of Nrf2 and the accompanying reduced transcription of Nrf2 and its regulated detoxifying genes. We aimed to investigate the effects of (3E,5E)-3,5-bis-(3,4,5-trimethoxybenzylidene)-tetrahydro-thiopyran-4-one (F10) and (3E,5E)-3,5-bis-(3,4,5-trimethoxy-benzylidene)-tetrahydropyran-4-one (E10), two synthetic curcumin derivatives, on restoring Nrf2 activity in TRAMP C1 cells. HepG2-C8 cells transfected with an antioxidant-response element (ARE)-luciferase vector were treated with F10, E10, curcumin, and sulforaphane (SFN) to compare their effects on Nrf2-ARE pathways. We performed real-time quantitative PCR and Western blotting to investigate the effects of F10 and E10 on Nrf2, correlated phase II detoxification genes. We also measured expression and activity of DNMTand HDAC enzymes. Enrichment of H3K27me3 on the promoter region of Nrf2 was explored with a chromatin immunoprecipitation (ChIP) assay. Methylation of the CpG region in Nrf2 promoter was doubly examined by bisulfite genomic sequencing (BGS) and methylation DNA immunoprecipitation (MeDIP). Compared with curcumin and SFN, F10 is more potent in activating Nrf2-ARE pathways. Both F10 and E10 enhanced level of Nrf2 and the correlated phase II detoxifying genes. BGS and MeDIP assays indicated that F10 but not E10 hypomethylated the Nrf2 promoter. F10 also downregulated the protein level of DNMT1, DNMT3a, DNMT3b, HDAC1, HDAC4, and HDAC7 and the activity of DNMTs and HDACs. F10 but not E10 effectively reduced the accumulation of H3k27me3 on the promoter of Nrf2. F10 and E10 can activate the Nrf2-ARE pathway and increase the level of Nrf2 and correlated phase II detoxification genes. The reactivation effect on Nrf2 by F10 in TRAMP C1 may come from demethylation, decrease of HDACs, and inhibition of H3k27me3 accumulation.

[Docking-based virtual screening of MEK1 inhibitors from Chinese herbs].

The hyperphosphorylation of MEK1(mitogen-activated protein kinase kinase 1) is one of the causesfor melanoma. It is important to discover a potential medicine for melanoma through virtual screening of chemical composition of Chinese material medica on MEK1. In this study, a docking pocket model and Flex Search model were built by using a MEK1 crystal structure, the similarity between connector conformation and gametophyte conformation in the crystal structure was 0.784.There was a linear relationship between total score and pIC50on MEK1 inhibitors, with R²=0.937, which further indicated the reliability of the virtual screening model.The search library of traditional Chinese medicine database on the Lipinski's rule was docked with the pocket model, and then 50 compounds with a totalscore of more than 7.0 were obtained by the Flex model. In this paper, top 10 active ingredients in screening results showed atotal score of more than that of positive medicines. It is expected to further research the inhibition of MEK1 and melanoma.

Mechanistic Study of Inhibitory Effects of Metformin and Atorvastatin in Combination on Prostate Cancer Cells in Vitro and in Vivo.

Metformin is a commonly used drug for the treatment of type II diabetes and atorvastatin is the most prescribed cholesterol-lowering statin. The present study investigated the effects and mechanisms of metformin and atorvastatin in combination on human prostate cancer cells cultured in vitro and grown as xenograft tumor in vivo. Metformin in combination with atorvastatin had stronger effects on growth inhibition and apoptosis in PC-3 cells than either drug alone. The combination also potently inhibited cell migration and the formation of tumorspheres. Metformin and atorvastatin in combination had a potent inhibitory effect on nuclear factor-kappaB (NF-κB) activity and caused strong decreases in the expression of its downstream anti-apoptotic gene Survivin. Moreover, strong decreases in the levels of phospho-Akt and phosphor-extracellular signal-regulated kinase (Erk)1/2 were found in the cells treated with the combination. The in vivo study showed that treatment of severe combined immunodeficient (SCID) mice with metformin or atorvastatin alone resulted in moderate inhibition of tumor growth while the combination strongly inhibited the growth of the tumors. Results of the present study indicate the combination of metformin and atorvastatin may be an effective strategy for inhibiting the growth of prostate cancer and should be evaluated clinically.

Development of Phenothiazine-Based Theranostic Compounds That Act Both as Inhibitors of ß-Amyloid Aggregation and as Imaging Probes for Amyloid Plaques in Alzheimer's Disease.

Early detection of Alzheimer's disease (AD) is imperative in enabling the understanding and clinical treatment of this disorder, as well as in preventing its progression. Imaging agents specifically targeting Aß plaques in the brain and the retina may lead to the early diagnosis of AD. Among them, near-infrared fluorescent (NIRF) imaging has emerged as an attractive tool to noninvasively identify and monitor diseases during the preclinical and early stages. In the present study, we report the design, synthesis, and evaluation of a series of new near-infrared fluorescent probes. Most of these probes displayed maximum emission in PBS (>650 nm), which falls in the good range for NIRF probes. Among them, 4a1 showed the highest affinity toward Aß aggregates (Kd = 7.5 nM) and an excellent targeting ability for Aß plaques in slices of brain and retina tissue from double transgenic mice. These compounds are also found to effectively prevent Aß fibril formation and disaggregate preformed Aß fibrils, showing a promising potential as theranostic agents for the diagnosis and therapy of AD.

Anti-inflammatory activity effect of 2-substituted-1,4,5,6-tetrahydrocyclopenta[b]pyrrole on TPA-induced skin inflammation in mice.

2-Substituted-1,4,5,6-tetrahydrocyclopenta[b]pyrrole, a key structural moiety exiting in many bioactive molecules, has been shown to have excellent selective activity on COX-2. In the present study, the anti-inflammatory activity and the underlying molecular mechanism of 2-substituted-1,4,5,6-tetrahydrocyclopenta[b]pyrrole on skin inflammation were assessed by 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation in mice. Most of the compounds showed anti-inflammatory activity on TPA-induced skin inflammation. The anti-inflammatory activity of compound 4 showed higher anti-inflammatory activity than celecoxib (3.2-fold). Compound 4 pretreatment resulted in markedly suppression of TPA-induced IL-1ß, IL-6, TNF-α, and COX-2, respectively. Furthermore, the mechanical study indicated that the anti-inflammatory activity of compound 4 was associated with its ability to inhibit activation of factor kappa-κB (NF-κB) by blocking IκB kinase (IKK) activities. Accordingly, compound 4 could be used as a potential anti-inflammatory agent for skin inflammation.

Pyridine analogues of curcumin exhibit high activity for inhibiting CWR-22Rv1 human prostate cancer cell growth and androgen receptor activation.

The concentrations required for curcumin to exert its anticancer activity (IC50, 20 µM) are difficult to achieve in the blood plasma of patients, due to the low bioavailability of the compound. Therefore, much effort has been devoted to the development of curcumin analogues that exhibit stronger anticancer activity and a lower IC50 than curcumin. The present study investigated twelve pyridine analogues of curcumin, labeled as groups AN, BN, EN and FN, to determine their effects in CWR-22Rv1 human prostate cancer cells. The inhibitory effects of these compounds on testosterone (TT)-induced androgen receptor (AR) activity was determined by performing an AR-linked luciferase assay and by TT-induced expression of prostate-specific antigen. The results of the current study suggested that the FN group of analogues had the strongest inhibitory effect of growth on CWR-22Rv1 cultured cells, and were the most potent inhibitor of AR activity compared with curcumin, and the AN, BN and EN analogues. Thus, the results of the present study indicate the inhibition of the AR pathways as a potential mechanism for the anticancer effect of curcumin analogues in human prostate cancer cells. Furthermore, curcumin analogues with pyridine as a distal ring and tetrahydrothiopyran-4-one as a linker may be good candidates for the development of novel drugs for the treatment of prostate cancer, by targeting the AR signaling pathway.

Epigenetics Reactivation of Nrf2 in Prostate TRAMP C1 Cells by Curcumin Analogue FN1.

It has previously been shown that curcumin can effectively inhibit prostate cancer proliferation and progression in TRAMP mice, potentially acting through the hypomethylation of the Nrf2 gene promoter and hence activation of the Nrf2 pathway to enhance cell antioxidative defense. FN1 is a synthetic curcumin analogue that shows stronger anticancer activity than curcumin in other reports. We aimed to explore the epigenetic modification of FN1 that restores Nrf2 expression in TRAMP-C1 cells. Stably transfected HepG2-C8 cells were used to investigate the effect of FN1 on the Nrf2- antioxidant response element (ARE) pathway. Real-time quantitative PCR and Western blotting were applied to study the influence of FN1 on endogenous Nrf2 and its downstream genes. Bisulfite genomic sequencing (BGS) and methylated DNA immunoprecipitation (MeDIP) were then performed to examine the methylation profile of the Nrf2 promoter. An anchorage-independent colony-formation analysis was conducted to examine the tumor inhibition activity of FN1. Epigenetic modification enzymes, including DNMTs and HDACs, were investigated by Western blotting. The luciferase reporter assay indicated that FN1 was more potent than curcumin in activating the Nrf2-ARE pathway. FN1 increased the expression of Nrf2 and its downstream detoxifying enzymes. FN1 significantly inhibited the colony formation of TRAMP-C1 cells. BGS and MeDIP assays revealed that FN1 treatment (250 nM for 3 days) reduced the percentage of CpG methylation of the Nrf2 promoter. FN1 also downregulated epigenetic modification enzymes. In conclusion, our results suggest that FN1 is a novel anticancer agent for prostate cancer. In the TRAMP-C1 cell line, FN1 can increase the level of Nrf2 and downstream genes via activating the Nrf2-ARE pathway and inhibit the colony formation potentially through the decreased expression of keap1 coupled with CpG demethylation of the Nrf2 promoter. This CpG demethylation effect may come from decreased epigenetic modification enzymes, such as DNMT1, DNMT3a, DNMT3b, and HDAC4.

Terpenoid composition and the anticancer activity of Acanthopanax trifoliatus.

The petroleum ether and ethyl acetate fractions of extract from an edible and medicinal plant Acanthopanax trifoliatus were found to show significant inhibitory effects against SF-268, MCF-7, HepG2 and NCI-H460 cancer cells. Two new ursane-type triterpenoids, acantrifoic acid C (1) and acantrifoic acid D (2), along with five known triterpenoids (3-7) and eight known diterpenoids (8-15) were obtained from these two fractions. To the best of our knowledge, this is the first report concerning the isolation of compounds (5-12, 14, 15) from A. trifoliatus. Among all the isolated compounds, 3, 5 and 8 from the ethyl acetate fraction showed the strongest inhibitory effects against cancer cells, while 12 and 13 from the petroleum ether fraction showed moderate activities. These terpenoid compounds may be responsible for the anticancer activities of A. trifoliatus. Our study provides the first evidence that terpenoids from A. trifoliatus exert anticancer activities and indicates that A. trifoliatus may be a useful edible plant for further development of anticancer health supplement.

B5, a thioredoxin reductase inhibitor, induces apoptosis in human cervical cancer cells by suppressing the thioredoxin system, disrupting mitochondrion-dependent pathways and triggering autophagy.

The synthetic curcumin analog B5 is a potent inhibitor of thioredoxin reductase (TrxR) that has potential anticancer effects. The molecular mechanism underlying B5 as an anticancer agent is not yet fully understood. In this study, we report that B5 induces apoptosis in two human cervical cancer cell lines, CaSki and SiHa, as evidenced by the downregulation of XIAP, activation of caspases and cleavage of PARP. The involvement of the mitochondrial pathway in B5-induced apoptosis was suggested by the dissipation of mitochondrial membrane potential and increased expression of pro-apoptotic Bcl-2 family proteins. In B5-treated cells, TrxR activity was markedly inhibited with concomitant accumulation of oxidized thioredoxin, increased formation of reactive oxygen species (ROS), and activation of ASK1 and its downstream regulatory target p38/JNK. B5-induced apoptosis was significantly inhibited in the presence of N-acetyl-l-cysteine. Microscopic examination of B5-treated cells revealed increased presence of cytoplasmic vacuoles. The ability of B5 to activate autophagy in cells was subsequently confirmed by cell staining with acridine orange, accumulation of LC3-II, and measurement of autophagic flux. Unlike B5-induced apoptosis, autophagy induced by B5 is not ROS-mediated but a role for the AKT and AMPK signaling pathways is implied. In SiHa cells but not CaSki cells, B5-induced apoptosis was promoted by autophagy. These data suggest that the anticarcinogenic effects of B5 is mediated by complex interplay between cellular mechanisms governing redox homeostasis, apoptosis and autophagy.