Ethanolic Fenugreek Extract: Its Molecular Mechanisms against Skin Aging and the Enhanced Functions by Nanoencapsulation.

Fenugreek, or Trigonella foenum-graecum L. (family Leguminosae) seeds, are typically used as food supplements to increase postnatal lactation. Fenugreek extract displays antioxidative and anti-inflammatory properties, but its mechanisms against skin aging have not been exploited. In this research, we are the first to define an in vitro collagenase inhibitory activity of fenugreek extract (IC50 = 0.57 ± 0.02 mg/mL), which is 2.6 times more potent than vitamin C (IC50 = 1.46 mg/mL). Nanoencapsulation has been applied to improve the extract stability, and subsequently enhanced its bioactivities. Liponiosome encapsulating fenugreek extract (LNF) was prepared using a high-speed homogenizer, resulting in homogeneous spherical nanoparticles with sizes in the range of 174.7 ± 49.2 nm, 0.26 ± 0.04 in PdI, and 46.6 ± 7.4% of entrapment efficiency. LNF formulation significantly facilitated a sustained release and significantly enhanced skin penetration over the extracts, suggesting a potential use of LNF for transdermal delivery. The formulated LNF was highly stable, not toxic to human fibroblast, and was able to enhance cell viability, collagen production, and inhibit MMP1, MMP9, IL-6, and IL-8 secretions compared to the extract in the co-cultured skin model. Therefore, ethanolic fenugreek extract and its developed LNF display molecular mechanisms against skin aging and could potentially be used as an innovative ingredient for the prevention of skin aging.

Flavonoids kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone inhibit mitotic clonal expansion and induce apoptosis during the early phase of adipogenesis in 3T3-L1 cells.

OBJECTIVE: Kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone (DTMC) are two major flavonoids found in Chromolaena odorata Linn. leaf extract. The aim of this study was to elucidate the mechanism by which these two flavonoids exerted their effect on adipogenesis. The inhibitory effect of kaempferide and DTMC on adipocyte differentiation and their mechanisms involving mitotic clonal expansion (MCE) and apoptosis during the early stage of adipogenesis were investigated. METHODS: Confluent 3T3-L1 preadipocytes were induced to differentiate and exposed to the flavonoids during various phases of differentiation. Intracellular lipid accumulation, cell density and expression of the transcription factors peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding proteins α were assessed using AdipoRed, Oil red O and Western blot assays. Effects of both flavonoids on cell proliferation and apoptosis were also determined by carboxyfluorescein diacetate succinimidyl ester and annexin V-fluorescein isothiocyanate/propidium iodide-staining assays, respectively. RESULTS: Kaempferide and DTMC showed significant, concentration-dependent anti-adipogenic activity and effect on cell density in the early phase of adipogenesis. The expression of the transcription factors seemed to be reduced when the treatment was prolonged or in the early phase of adipogenesis. These flavonoids interrupted MCE via inhibition of preadipocyte proliferation and induction of apoptosis. DTMC was nearly three times more potent than kaempferide in inducing apoptosis. CONCLUSION: Kaempferide and DTMC exerted their anti-adipogenic activity through inhibition of MCE, either by suppressing cell proliferation or by inducing apoptosis during the early phase of differentiation.

Anti-adipogenic effect of flavonoids from Chromolaena odorata leaves in 3T3-L1 adipocytes.

OBJECTIVE: The leaves of Chromolaena odorata, a highly invasive shrub found growing wild worldwide, are traditionally used for wound healing. Due to its high flavonoid contents, we aimed to find a new application for this plant. Preliminary tests using its ethanolic leaf extract showed that it could suppress the accumulation of lipids in adipocytes. We therefore studied the anti-adipogenic effect of several C. odorata leaf extracts and the relationship between molecular structure and bio-activity of its isolated flavonoid constituents using 3T3-L1 preadipocytes/adipocytes as a model. METHODS: Three leaf extracts and thirteen flavonoids isolated from C. odorata were tested for their effect on lipid accumulation in 3T3-L1 adipocytes using AdipoRed reagent, with quercetin as the positive control. The effects of active flavonoids on the adipocytes were confirmed by oil red O staining and visualized under a light microscope. RESULTS: n-Hexane and ethyl acetate extracts of C. odorata leaves displayed anti-adipogenic activity. The latter extract was the more potent one, especially at 40 µg/mL. Four flavonoids, pectolinarigenin, kaempferide, 4,2'-dihydroxy-4',5',6'-trimethoxychalcone and dillenetin, exhibited significant, concentration-dependent inhibitory effects on lipid accumulation in 3T3-L1 adipocytes. The most potent flavonoid obtained in this study was 4,2'-dihydroxy-4',5',6'-trimethoxychalcone, which caused 75% and 90% inhibition of cellular lipid accumulation at 30 and 50 µmol/L, respectively. Both kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone were major constituents in the ethyl acetate extract of this plant. CONCLUSION: C. odorata leaves contained several flavonoids with anti-adipogenic effects against lipid accumulation in 3T3-L1 adipocytes. The plant, normally considered a useless weed, may actually provide an abundant source of biologically active flavonoids.

A Comparative of Ginger Extract in Nanostructure Lipid Carrier (NLC) and 1% Diclofenac Gel for Treatment of Knee Osteoarthritis (OA).

Objective: To compare and evaluate the efficacy of ginger (Zingiber officinale Roscoe) extracts in NLC for treatment of osteoarthritis of knee compared to 1% diclofenac gel as an active control. Material and Method: One hundred twenty patients age 50 to 75 years with OA knee, based on the American College of Rheumatology (ACR) criteria were randomized into two groups receiving ginger extracts in NLC and control 1% diclofenac gel for 12 weeks. The efficacy of treatment was monitored at 4, 8, and 12 weeks by using the WOMAC composite index and the Patient Global Assessment (PGA). The t-test was used to compare the mean scores at baseline in each group. Repeated ANOVA was used to compare the mean scores, and Chi-square test was used to compare the dichotomous variables between the two groups at 4, 8, and 12 weeks. Results: One hundred eighteen participants completed the study and were included in the ITT efficacy analysis. Both ginger extract in NLC and diclofenac gel could significantly improve knee pain, stiffness, physical function, and PGA following 12 weeks of treatment. In the repeated ANOVA, there were no differences in the result between these two groups. The response rate for at least a 50% reduction in pain was significantly greater following Ginger extract in NLC treatment compared to topical diclofenac [40/59 (67.7%) vs. 27/59 (45.7%) p<0.05]. There were no significant adverse events. Conclusion: Ginger extract in NLC relieves pain, improves function, and improves the Patient Global Assessment in OA knee during a 12-week treatment.

Improving of Knee Osteoarthritic Symptom by the Local Application of Ginger Extract Nanoparticles: A Preliminary Report with Short Term Follow-Up.

OBJECTIVE: An evaluation ofthe efficacy and safety of Ginger (Zingiber officinale Roscoe) extract nanoparticlefor treatment of osteoarthritis (OA) of the knee. MATERIAL AND METHOD: Sixty patients at the age range of 50 to 75 years old who were diagnosed with OA knee based on the American College of Rheumatology (ACR) diagnosis criteria were included in the present study. Participants received ginger extract in Nanostructure Lipid Carrier (NLC) rubbed three times a day for 12 weeks. Efficacy was assessed by Knee Injury and Osteoarthritis Outcome Score (KOOS), Index of Severityfor Osteoarthritis (ISOA), and patient's global assessment (PGA). A series of biochemical tests in serum and hematological parameters were established the safety of ginger extract in NLC. The paired t-test was used to compare the score before and after treatment. The comparisons of baseline and the 4-, 8-, and 12-week used repeated ANOVA. RESULTS: Ginger .extract nanoparticles improved, with statistical significance, the patient's global assessment, knee joint pain, symptoms, daily activities, sports activities, and quality of life measured by KOOS, ISOA, andPGA, following 12 weeks of treatment (p<0.05). There were no safety issues, adverse events, or laboratory values. CONCLUSION: Ginger extract nanoparticles relieves joint pain and improves problematic symptoms and improves the quality of life in osteoarthritis knees during a 12-week treatment.

The interaction mechanism between lipopeptide (daptomycin) and polyamidoamine (PAMAM) dendrimers.

The interaction mechanism of lipopeptide antibiotic daptomycin and polyamidoamine (PAMAM) dendrimers was studied using fluorescence spectroscopy. The fluorescence changes observed are associated with daptomycin-dendrimer interactions. The binding isotherms were constructed by plotting the fluorescence difference at 460 nm from kynurenine (Kyn-13) of daptomycin in the presence and absence of dendrimer. A one-site and two-site binding model were quantitatively generated to estimate binding capacity and affinity constants from the isotherms. The shape of the binding isotherm and the dependence of the estimated capacity constants on dendrimer sizes and solvent pH values provide meaningful insight into the mechanism of interactions. A one-site binding model adequately describes the binding isotherm obtained under a variety of experimental conditions with dendrimers of various sizes in the optimal binding pH region 3.5 to 4.5. Comparing the pH-dependent binding capacity with the ionization profiles of daptomycin and dendrimer, the ionized aspartic acid residue (Asp-9) of daptomycin primarily interact with PAMAM cationic surface amine.

Molecular signalings in keloid disease and current therapeutic approaches from natural based compounds.

CONTEXT: Keloid is an excessive dermal scar occurring in response to skin injuries. Several therapeutic strategies have been proposed to ease the aggressiveness of keloid scarring. Even though the principle mechanism underlying the disease propagation still remains unidentified, several signaling pathways were highly focused as plausible pathways involving keloid formation, including transforming growth factor-beta 1 (TGF-ß1), mitogen-activated protein kinase (MAPK), insulin-like growth factor-I (IGF-I), and integrin pathways. Natural compounds containing multiple bioeffective properties such as quercetin, asiaticoside, Astragalus membranaceus Bunge. (Leguminosae), and Salvia miltiorrhiza Bunge. (Lamiaceae) extracts, curcuminoids, oxymatrine, madecassoside, and Aneilema keisak Hassk. (Commelinaceae) are claimed as candidates for therapeutic treatment against keloid disorder. OBJECTIVE: This review investigates current mechanisms regarding keloid formation and provides scientific evidence supporting the therapeutic potential of natural compounds. METHODS: This review obtained and analyzed a number of literature data items from various databases including Pubmed, ScienceDirect, and Elton B. Stephens Company (EBSCO). RESULT: Several phytochemical compounds are able to suppress keloid scar development through manipulating various components in the complex signaling cascades. CONCLUSION: The present review may be helpful to future studies that further examine the molecular mechanism of keloid etiology as well as investigate the anti-keloid property in natural compounds.

Carbon nanotubes induce apoptosis resistance of human lung epithelial cells through FLICE-inhibitory protein.

Chronic exposure to single-walled carbon nanotubes (SWCNT) has been reported to induce apoptosis resistance of human lung epithelial cells. As resistance to apoptosis is a foundation of neoplastic transformation and cancer development, we evaluated the apoptosis resistance characteristic of the exposed lung cells to understand the pathogenesis mechanism. Passage control and SWCNT-transformed human lung epithelial cells were treated with known inducers of apoptosis via the intrinsic (antimycin A and CDDP) or extrinsic (FasL and TNF-α) pathway and analyzed for apoptosis by DNA fragmentation, annexin-V expression, and caspase activation assays. Whole-genome microarray was performed to aid the analysis of apoptotic gene signaling network. The SWCNT-transformed cells exhibited defective death receptor pathway in association with cellular FLICE-inhibitory protein (c-FLIP) overexpression. Knockdown or chemical inhibition of c-FLIP abrogated the apoptosis resistance of SWCNT-transformed cells. Whole-genome expression signature analysis confirmed these findings. This study is the first to demonstrate carbon nanotube-induced defective death receptor pathway and the role of c-FLIP in the process.

Mitochondrial superoxide mediates doxorubicin-induced keratinocyte apoptosis through oxidative modification of ERK and Bcl-2 ubiquitination.

Massive apoptosis of keratinocytes has been implicated in the pathogenesis of chemotherapy-induced skin toxicities, but the underlying mechanisms of action are not well understood. The present study investigated the apoptotic effect of doxorubicin (DOX) on HaCaT keratinocytes and determined the underlying mechanisms. Treatment of the cells with DOX induced reactive oxygen species (ROS) generation and a concomitant increase in apoptotic cell death through the mitochondrial death pathway independent of p53. Electron spin resonance and flow cytometry studies showed that superoxide is the primary oxidative species induced by DOX and responsible for the death inducing effect. Ectopic expression of mitochondrial superoxide scavenging enzyme (MnSOD) or treatment with MnSOD mimetic (MnTBAP) inhibited DOX-induced superoxide generation and apoptosis. The mechanism by which superoxide mediates the apoptotic effect of DOX was shown to involve downregulation of Bcl-2 through ubiquitin-proteasomal degradation. Superoxide induces dephosphorylation of Bcl-2 through MAP kinase ERK1/2 inactivation, which promotes ubiquitination of Bcl-2. We also provide evidence for the oxidative modification of ERK1/2 through cysteine sulfenic acid formation. These findings indicate a novel pathway for redox regulation of apoptosis regulatory proteins, which could be important in the understanding of chemotherapy-induced toxicities and development of preventive treatment strategies which are currently lacking.

Effects of different carboxylic ester spacers on chemical stability, release characteristics, and anticancer activity of mono-PEGylated curcumin conjugates.

We investigated the effects of different carboxylic ester spacers of mono-PEGylated curcumin conjugates on chemical stability, release characteristics, and anticancer activity. Three novel conjugates were synthesized with succinic acid, glutaric acid, and methylcarboxylic acid as the respective spacers between curcumin and monomethoxy polyethylene glycol of molecular weight 2000 (mPEG(2000) ): mPEG(2000) -succinyl-curcumin (PSC), mPEG(2000) -glutaryl-curcumin (PGC), and mPEG(2000) -methylcarboxyl-curcumin (PMC), respectively. Hydrolysis of all conjugates in buffer and human plasma followed pseudo first-order kinetics. In phosphate buffer, the overall degradation rate constant and half-life values indicated an order of stability of PGC > PSC > PMC > curcumin. In human plasma, more than 90% of curcumin was released from the esters after incubation for 0.25, 1.5, and 2 h, respectively. All conjugates exhibited cytotoxicity against four human cancer cell lines: Caco-2 (colon), KB (oral cavity), MCF7 (breast), and NCI-H187 (lung) with half maximal inhibitory concentration (IC(50) ) values in the range of 1-6 µM, similar to that observed for curcumin itself. Our results suggest that mono-PEGylation of curcumin produces prodrugs that are stable in buffer at physiological pH, release curcumin readily in human plasma, and show anticancer activity.

Hydroxyl radical mediates cisplatin-induced apoptosis in human hair follicle dermal papilla cells and keratinocytes through Bcl-2-dependent mechanism.

Induction of massive apoptosis of hair follicle cells by chemotherapy has been implicated in the pathogenesis of chemotherapy-induced alopecia (CIA), but the underlying mechanisms of regulation are not well understood. The present study investigated the apoptotic effect of cisplatin in human hair follicle dermal papilla cells and HaCaT keratinocytes, and determined the identity and role of specific reactive oxygen species (ROS) involved in the process. Treatment of the cells with cisplatin induced ROS generation and a parallel increase in caspase activation and apoptotic cell death. Inhibition of ROS generation by antioxidants inhibited the apoptotic effect of cisplatin, indicating the role of ROS in the process. Studies using specific ROS scavengers further showed that hydroxyl radical, but not hydrogen peroxide or superoxide anion, is the primary oxidative species responsible for the apoptotic effect of cisplatin. Electron spin resonance studies confirmed the formation of hydroxyl radicals induced by cisplatin. The mechanism by which hydroxyl radical mediates the apoptotic effect of cisplatin was shown to involve down-regulation of the anti-apoptotic protein Bcl-2 through ubiquitin-proteasomal degradation. Bcl-2 was also shown to have a negative regulatory role on hydroxyl radical. Together, our results indicate an essential role of hydroxyl radical in cisplatin-induced cell death of hair follicle cells through Bcl-2 regulation. Since CIA is a major side effect of cisplatin and many other chemotherapeutic agents with no known effective treatments, the knowledge gained from this study could be useful in the design of preventive treatment strategies for CIA through localized therapy without compromising the chemotherapy efficacy.

Synthesis, characterization and biological evaluation of succinate prodrugs of curcuminoids for colon cancer treatment.

A novel series of succinyl derivatives of three curcuminoids were synthesized as potential prodrugs. Symmetrical (curcumin and bisdesmethoxycurcumin) and unsymmetrical (desmethoxycurcumin) curcuminoids were prepared through aldol condensation of 2,4-pentanedione with different benzaldehydes. Esterification of these compounds with a methyl or ethyl ester of succinyl chloride gave the corresponding succinate prodrugs in excellent yields. Anticolon cancer activity of the compounds was evaluated using Caco-2 cells. The succinate prodrugs had IC50 values in the 1.8-9.6 µM range, compared to IC50 values of 3.3-4.9 µM for the parent compounds. Curcumin diethyl disuccinate exhibited the highest potency and was chosen for stability studies. Hydrolysis of this compound in phosphate buffer at pH 7.4 and in human plasma followed pseudo first-order kinetics. In phosphate buffer, the k(obs) and t(½) for hydrolysis indicated that the compound was much more stable than curcumin. In human plasma, this compound was able to release curcumin, therefore our results suggest that succinate prodrugs of curcuminoids are stable in phosphate buffer, release the parent curcumin derivatives readily in human plasma, and show anti-colon cancer activity.

Hydrogen peroxide inhibits non-small cell lung cancer cell anoikis through the inhibition of caveolin-1 degradation.

Anoikis or detachment-induced apoptosis plays an essential role in the regulation of cancer cell metastasis. Caveolin-1 (Cav-1) is a key protein involved in tumor metastasis, but its role in anoikis and its regulation during cell detachment are unclear. We report here that Cav-1 plays a key role as a negative regulator of anoikis through a reactive oxygen species (ROS)-dependent mechanism in human lung carcinoma H460 cells. During cell detachment, Cav-1 is downregulated, whereas ROS generation is upregulated. Hydrogen peroxide and hydroxyl radical are two key ROS produced by cells during detachment. Treatment of the cells with hydrogen peroxide scavengers, catalase and N-acetylcysteine, promoted Cav-1 downregulation and anoikis during cell detachment, indicating that produced hydrogen peroxide plays a primary role in preventing anoikis by stabilizing Cav-1 protein. Catalase and N-acetylcysteine promoted ubiquitination and proteasomal degradation of Cav-1, which is a major pathway of its downregulation during cell anoikis. Furthermore, addition of hydrogen peroxide exogenously to the cells inhibited Cav-1 downregulation by preventing the formation of Cav-1-ubiquitin complex, supporting the inhibitory role of endogenous hydrogen peroxide in Cav-1 degradation during cell detachment. Together, these results indicate a novel role of hydrogen peroxide as an endogenous suppressor of cell anoikis through its stabilizing effect on Cav-1.

Protection of HT22 neuronal cells against glutamate toxicity mediated by the antioxidant activity of Pueraria candollei var. mirifica extracts.

Neuronal degeneration is known to be due to oxidative stress acting through a pathway involving the excessive activation of glutamate receptors. We studied the neuroprotection potential of an ethyl acetate-ethanol extract of Pueraria mirifica (P. candollei var. mirifica) root (PM extract). PM extract was evaluated for its antioxidant and neuroprotective activities against glutamate toxicity in mouse hippocampal HT22 neuronal cells. The extract at concentrations of 10 and 50 µg/ml exhibited considerable antioxidant activity with significant neuroprotection, based on the microscopic observations of cell morphology and the determination of cell viability and cell number. Studies of the possible mechanisms of action indicated that the neuroprotection exerted by PM extract was related to its scavenging activity against H(2)O(2) and related reactive oxygen species. High-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) analyses showed that the extract contained daidzein and genistein as identified constituents, as well as additional components with antioxidant activity. While daidzein and genistein individually and in combination were observed not to be neuroprotective, we propose that the antioxidant and neuroprotective activities of PM extract are derived from the combined properties of its constituents.

Regulation of lung cancer cell migration and invasion by reactive oxygen species and caveolin-1.

The acquired capability of tumor cells to migrate and invade neighboring tissues is associated with high metastatic potential and advanced stage of cancers. Recently, signaling molecules such as reactive oxygen species (ROS) and caveolin-1 (Cav-1) have been implicated in the aggressive behavior of cancer cells. However, the roles of specific ROS in cancer cell migration and Cav-1 regulation are unclear. We demonstrate here that Cav-1 plays an important role in the migration and invasion of human lung carcinoma H460 cells and that these effects are differentially regulated by cellular ROS. Using various known inhibitors and donors of ROS, we found that different ROS have different effects on Cav-1 expression and cell migration and invasion. Superoxide anion and hydrogen peroxide down-regulated Cav-1 expression and inhibited cell migration and invasion, whereas hydroxyl radical up-regulated the Cav-1 expression and promoted cell migration and invasion. The down-regulating effect of superoxide anion and hydrogen peroxide on Cav-1 is mediated through a transcription-independent mechanism that involves protein degradation via the ubiquitin-proteasome pathway. These results indicate the essential role of different ROS in cancer cell motility and through Cav-1 expression, which may provide a key mechanism controlling tumor progression and metastasis. The up-regulation of Cav-1 and cell motility by hydroxyl free radical suggests an important role of this ROS as a positive regulator of tumor progression.

Curcumin sensitizes non-small cell lung cancer cell anoikis through reactive oxygen species-mediated Bcl-2 downregulation.

Anoikis, an apoptosis triggered by loss of cell anchorage, has been shown to be a principal mechanism of inhibition of tumor metastasis. Recently, anti-apoptotic Bcl-2 and Cav-1 proteins have been demonstrated to be highly associated with tumor metastasis and apoptosis resistance. Curcumin, a major active component of turmeric, Curcuma longa, has been shown to inhibit neoplastic evolution and tumor progression; however, the underlying mechanisms are unclear. In this study, we investigated the effect of curcumin on cell anoikis as a possible mechanism of anti-tumorigenic action of curcumin, and evaluated the potential role of Bcl-2 and Cav-1 in this process. Our results showed that ectopic expression of either Bcl-2 or Cav-1 induced anoikis resistance of lung carcinoma H460 cells. Curcumin downregulated Bcl-2 protein during anoikis and sensitized the cells to detachment-induced apoptosis, whereas it had no significant effect on Cav-1 protein expression. Bcl-2 down-regulation as well as anoikis enhancement by curcumin were inhibited by superoxide anion scavenger, Mn(III)tetrakis(4-benzoic acid) porphyrin chloride, but were unaffected by other ROS scavengers including catalase and deferoxamine, suggesting that superoxide anion is a key player in the downregulation of Bcl-2 by curcumin. Furthermore, we provided evidence that curcumin decreased Bcl-2 level through ubiquitin-proteasomal degradation which sensitized cells to detachment-induced apoptosis. These findings indicate a novel pathway for curcumin regulation of Bcl-2 and provide a key mechanism of anoikis regulation that may be exploited for metastatic cancer treatment.

Type I pro-collagen promoting and anti-collagenase activities of Phyllanthus emblica extract in mouse fibroblasts.

As part of an ongoing search for the novel pharmacological activities of Phyllanthus emblica, the present study has shown its type I collagen promoting and anti-collagenase effects on primary mouse fibroblast cells. At a concentration of 0.1 mg/ml, emblica extract significantly increased the type I pro-collagen level up to 1.65-fold, and 6.78-fold greater than that of an untreated control, determined by immunocytochemistry and Western blot analysis, respectively. Emblica extract caused an approximately 7.75-fold greater type I pro-collagen induction compared to the known herbal collagen enhancer asiaticoside at the same treatment concentration (0.1 mg/ml). Moreover, emblica extract inhibited collagenase activity in a dose-dependent manner. Maximal inhibition was observed (78.67 +/- 3.51%) at a concentration of 1 mg/ml. In summary, emblica extract has a promising pharmacological effect that benefits collagen synthesis and protects against its degradation and could be used as a natural anti-aging ingredient.

Nitric oxide regulates lung carcinoma cell anoikis through inhibition of ubiquitin-proteasomal degradation of caveolin-1.

Anoikis, a detachment-induced apoptosis, is a principal mechanism of inhibition of tumor cell metastasis. Tumor cells can acquire anoikis resistance which is frequently observed in metastatic lung cancer. This phenomenon becomes an important obstacle of efficient cancer therapy. Recently, signaling mediators such as caveolin-1 (Cav-1) and nitric oxide (NO) have garnered attention in metastasis research; however, their role and the underlying mechanisms of metastasis regulation are largely unknown. Using human lung carcinoma H460 cells, we show that NO impairs the apoptotic function of the cells after detachment. The NO donors sodium nitroprusside and diethylenetriamine NONOate inhibit detachment-induced apoptosis, whereas the NO inhibitors aminoguanidine and 2-(4-carboxyphenyl) tetramethylimidazoline-1-oxyl-3-oxide promote this effect. Resistance to anoikis in H460 cells is mediated by Cav-1, which is significantly down-regulated after cell detachment through a non-transcriptional mechanism involving ubiquitin-proteasomal degradation. NO inhibits this down-regulation by interfering with Cav-1 ubiquitination through a process that involves protein S-nitrosylation, which prevents its proteasomal degradation and induction of anoikis by cell detachment. These findings indicate a novel pathway for NO regulation of Cav-1, which could be a key mechanism of anoikis resistance in tumor cells.

An evaluation of a fluorometric method for determining binding parameters of drug-carrier complexes using mathematical models based on total drug concentration.

A fluorescence method for determining the mode of binding and estimating binding parameters in a model drug-carrier complex was developed using the lipopeptide antibiotic daptomycin and polyamidoamine (PAMAM) dendrimer. Mathematical simulations of model equations describing fluorescence changes induced by antibiotic-carrier binding in terms of total drug concentration were used to evaluate the sensitivity of parameter variation on binding isotherms for both one- and two-site binding models. Nonlinear regression analysis was used to estimate binding parameters and to identify pH-dependent binding models.

Curcumin sensitizes lung cancer cells to cisplatin-induced apoptosis through superoxide anion-mediated Bcl-2 degradation.

The purpose of this study was to investigate the sensitizing effect of curcumin on cisplatin-induced apoptosis in non-small cell lung cancer (NSCLC) H460 cells. Curcumin was shown to induce superoxide anion generation, down-regulate anti-apoptotic Bcl-2 protein, and subsequently sensitize cells to cisplatin-induced apoptosis. Co-treatment of the cells with curcumin and cisplatin resulted in increased apoptosis and reversal of Bcl-2-mediated cisplatin resistance. The mechanism by which curcumin down-regulates Bcl-2 and sensitizes cells to cisplatin-induced apoptosis involves proteasomal degradation of Bcl-2. These findings indicate a novel pathway for curcumin regulation of Bcl-2, which could benefit the development of a cisplatin sensitizing agent.