Resveratrol induces mitochondria-mediated AIF and to a lesser extent caspase-9-dependent apoptosis in human lung adenocarcinoma ASTC-a-1 cells

Arachidin-1, a Prenylated Stilbenoid from Peanut, Induces Apoptosis in Triple-Negative Breast Cancer Cells

Triple-negative breast cancer (TNBC) is unresponsive to typical hormonal treatments, causing it to be one of the deadliest forms of breast cancer. Investigating alternative therapies to increase survival rates for this disease is essential. The goal of this study was to assess cytotoxicity and apoptosis mechanisms of prenylated stilbenoids in TNBC cells. The prenylated stilbenoids arachidin-1 (A-1) and arachidin-3 (A-3) are analogs of resveratrol (RES) produced in peanut upon biotic stress. The anticancer activity of A-1 and A-3 isolated from peanut hairy root cultures was determined in TNBC cell lines MDA-MB-231 and MDA-MB-436. After 24 h of treatment, A-1 exhibited higher cytotoxicity than A-3 and RES with approximately 11-fold and six-fold lower IC50, respectively, in MDA-MB-231 cells, and nine-fold and eight-fold lower IC50, respectively, in MDA-MB-436 cells. A-1 did not show significant cytotoxicity in the non-cancerous cell line MCF-10A. While A-1 blocked cell division in G2-M phases in the TNBC cells, it did not affect cell division in MCF-10A cells. Furthermore, A-1 induced caspase-dependent apoptosis through the intrinsic pathway by activating caspase-9 and PARP cleavage, and inhibiting survivin. In conclusion, A-1 merits further research as a potential lead molecule for the treatment of TNBC.

Resveratrol shortens the chronological lifespan of Saccharomyces cerevisiae by a pro-oxidant mechanism

The antioxidant phenotype caused by resveratrol has been recognized as a key piece in the health benefits exerted by this phytochemical in diseases related to aging. It has recently been proposed that a mitochondrial pro-oxidant mechanism could be the cause of resveratrol antioxidant properties. In this regard, the hypothesis that resveratrol impedes electron transport to complex III of the electron transport chain as its main target suggests that resveratrol could increase reactive oxygen species (ROS) generation through reverse electron transport or by the semiquinones formation. This idea also explains that cells respond to resveratrol oxidative damage, inducing their antioxidant systems. Moreover, resveratrol pro-oxidant properties could accelerate the aging process, according to the free radical theory of aging, which postulates that organism's age due to the accumulation of the harmful effects of ROS in cells. Nonetheless, there is no evidence linking the chronological lifespan (CLS) shorten occasioned by resveratrol with a pro-oxidant mechanism. Hence, this study aimed to evaluate whether resveratrol shortens the CLS of Saccharomyces cerevisiae due to a pro-oxidant activity. Herein, we provide evidence that supplementation with 100 μM of resveratrol at 5% glucose: (1) shortened the CLS of ctt1Δ and yap1Δ strains; (2) decreased ROS levels and increased the catalase activity in WT strain; (3) maintained unaffected the ROS levels and did not change the catalase activity in ctt1Δ strain; and (4) lessened the exponential growth of ctt1Δ strain, which was restored with the adding of reduced glutathione. These results indicate that resveratrol decreases CLS by a pro-oxidant mechanism.

Resveratrol cytotoxicity is energy-dependent

Resveratrol is a phytochemical that may promote health. However, it has also been reported to be a toxic compound. The molecular mechanism by which resveratrol acts remains unclear. The inhibition of the oxidative phosphorylation (OXPHOS) pathway appears to be the molecular mechanism of resveratrol. Taking this into account, we propose that the cytotoxic properties of resveratrol depend on the energy (e.g., carbohydrates, lipids, and proteins) availability in the cells. In this regard, in a condition with low energy accessibility, resveratrol could enhance ATP starvation to lethal levels. In contrast, when cells are supplemented with high quantities of energy and resveratrol, the inhibition of OXPHOS might produce a low-energy environment, mimicking the beneficial effects of caloric restriction. This review suggests that investigating a possible complex relationship between caloric intake and the differential effects of resveratrol on OXPHOS may be justified. PRACTICAL APPLICATIONS: A low-calorie diet accompanied by significant levels of resveratrol might modify cellular bioenergetics, which could impact cellular viability and enhance the anti-cancer properties of resveratrol.

Resveratrol alleviates inflammatory injury and enhances the apoptosis of fibroblast‑like synoviocytes via mitochondrial dysfunction and ER stress in rats with adjuvant arthritis

Resveratrol, a bioactive compound predominantly found in grapes and red wine, provides a wide range of properties that are beneficial for health, including anticancer and anti-inflammatory activities. Previously published studies have addressed the potential therapeutic effects of resveratrol on rheumatoid arthritis (RA); however, the subcellular mechanism remains to be fully elucidated. In the present study, the therapeutic effects of resveratrol on adjuvant arthritis (AA) in Sprague-Dawley rats were investigated, and the mechanisms of resveratrol-induced apoptosis in fibroblast-like synoviocytes (FLSs) were further examined. Based on the findings, resveratrol treatment over a 12-day period led to a reduction in paw swelling and arthritis scores at the macroscopic level, and an attenuation of inflammatory cell infiltration and synovial hyperplasia, upon a histopathological examination of the AA rats. Furthermore, the administration of resveratrol triggered decreases in the expression of interleukin (IL)-1, IL-6, IL-8 and tumor necrosis factor-α (TNF-α) and an increase in the expression of IL-10, alleviating inflammatory injury in AA rats in a dose-dependent manner. In addition, resveratrol was revealed to induce the apoptosis of FLSs when administered with 5 µM H₂O₂ as determined by elevated levels of Bax, caspase-3, caspase-12 and C/EBP-homologous protein, and the downregulation of B-cell lymphoma 2 (Bcl-2), suggesting that resveratrol is able to induce apoptosis in FLSs via the mitochondrial pathway and endoplasmic reticulum (ER) stress in a milieu containing 5 µM H₂O₂. Furthermore, JC-1 was used as a fluorescent probe to detect the mitochondrial membrane potential (Δψm), and resveratrol was shown to reduce the Δψm in FLSs in the presence of 5 µM H₂O₂. However, resveratrol was not able to trigger intracellular calcium overload, although it did suppress ATP- and thapsigargin-induced calcium release from the ER. In conclusion, the present study revealed that resveratrol was able to alleviate inflammatory injury in AA rats, triggering the apoptosis of FLSs via the mitochondrial pathway and ER stress. These results provide a theoretical basis for future treatments using resveratrol for RA.

Resveratrol protects photoreceptors by blocking caspase- and PARP-dependent cell death pathways

Retinal degeneration is a major cause of severe vision loss and irreversible blindness and is characterized by progressive damage to retinal photoreceptor cells. Resveratrol (RSV) serves as an activator of the histone deacetylase, Sirt1, and has been shown to exert anti-oxidative properties. In this study, we mimicked retinal degeneration by subjecting photoreceptors (661 W cells) to glucose deprivation (GD) or light exposure. Under these conditions, we investigated the mechanisms underlying GD- or light exposure-induced cell death and the protective effect of RSV. We found that GD and light exposure resulted in mitochondrial dysfunction, oxidative stress, and cell death. Treatment of injured cells with RSV decreased the production of reactive oxygen species (ROS), improved the ratio of reduced/oxidized glutathione (GSH/GSSG), mitochondrial membrane potential and morphology, and reduced apoptosis. We used the caspase inhibitor, z-VAD-fmk, and a lentiviral-mediated shRNA knockdown of PARP-1 to reveal that GD and light exposure-induced cell death have different underlying mechanisms; GD triggered a caspase-dependent cell death pathway, whereas light exposure triggered a PARP-dependent cell death pathway. The level of caspase-9 and caspase-3, upregulated following GD, were reduced by treatment with RSV. Similarly, the level of PARP-1 and AIF, upregulated following light exposure, were decreased by treatment with RSV. Additionally, treatment with RSV elevated the protein expression and enzymatic activity of Sirt1 and a Sirt1 inhibitor reduced the protective effect of RSV against insult-induced cellular injuries, indicating that RSV's protective effect may involve Sirt1 activation. Finally, we investigated the neuroprotection of RSV in vivo. Administration of RSV to mice under extreme light exposure led to a suppression of the light-induced thinning of the outer nuclear layer (ONL) detected by hematoxylin and eosin (H&E) staining and restored retinal function evaluated by electroretinography (ERG). Taken together, our findings provide evidence that treatment with RSV has neuroprotective effects on both GD and light exposure-induced cell death pathways in photoreceptor cells.

Detection of Mitochondria Membrane Potential to Study CLIC4 Knockdown-induced HN4 Cell Apoptosis In Vitro

Depletion of the mitochondrial membrane potential (MMP, ΔΨm) is considered the earliest event in the apoptotic cascade. It even occurs ahead of nuclear apoptotic characteristics, including chromatin condensation and DNA breakage. Once the MMP collapses, cell apoptosis will initiate irreversibly. A series of lipophilic cationic dyes can pass through the cell membrane and aggregate inside the matrix of mitochondrion, and serve as fluorescence marker to evaluate MMP change. As one of the six members of the Cl^- intracellular channel (CLIC) family, CLIC4 participates in the cell apoptotic process mainly through the mitochondrial pathway. Here we describe a detailed protocol to measure MMP via monitoring the fluorescence fluctuation of Rhodamine 123 (Rh123), through which we study apoptosis induced by CLIC4 knockdown. We discuss the advantages and limitations of the application of confocal laser scanning and normal fluorescence microscope in detail, and also compare it with other methods.

Miltirone-induced apoptosis in cisplatin-resistant lung cancer cells through upregulation of p53 signaling pathways

The active ingredients of natural plants are important sources of antitumor agents. Miltirone is a major effective ingredient in traditional Chinese medicine and it is considered to have anti-infection and immunosuppressive activities. Clinically, it is often used for the treatment of arthritis and immune diseases. The effect of miltirone on cisplatin-resistant lung cancer cells has not been investigated to date. The present study aimed to examine the anticancer effect of miltirone in cisplatin-resistant lung cancer cells. Treatment with miltirone suppressed cell viability and induced apoptosis in HCC827 and A549 platinum-resistant lung cancer cells. It was also revealed that miltirone increased caspase-3/8 activity as well as B-cell lymphoma 2-associated X-protein, apoptosis-inducing factor (AIF), p53 and poly(ADP-ribose) polymerase (PARP) protein expression, whereas it inhibited mitochondrial reactive oxygen species (ROS) generation and matrix metalloproteinase (MMP)-2/9 protein expression in HCC827 and A549 platinum-resistant lung cancer cells. The results of the present study demonstrated that miltirone induces apoptosis in cisplatin-resistant lung cancer cells through ROS-p53, AIF, PARP and MMP2/9 signaling pathways.

Resveratrol induces mitochondria-mediated, caspase-independent apoptosis in murine prostate cancer cells

Found in the skins of red fruits, including grapes, resveratrol (RES) is a polyphenolic compound with cancer chemopreventive activity. Because of this activity, it has gained interest for scientific investigations. RES inhibits tumor growth and progression by targeting mitochondria-dependent or -independent pathways. However, further investigations are needed to explore the underlying mechanisms.

The present study is focused on examining the role of RES-induced, mitochondria-mediated, caspase-independent apoptosis of prostate cancer cells, namely transgenic adenocarcinoma of mouse prostate (TRAMP) cells. These cells were exposed to RES for various times, and cell killing, cell morphology, mitochondrial membrane potential (Δψm), expression of Bax and Bcl2 proteins, the role of caspase-3, and DNA fragmentation were analyzed.

TRAMP cells exposed to RES showed decreased cell viability, altered cell morphology, and disrupted Δψm, which led to aberrant expression of Bax and Bcl2 proteins. Furthermore, since the caspase-3 inhibitor, z-VAD-fmk (benzyloxycarbonyl-valine-alanine-aspartic acid-fluoromethyl ketone), had no appreciable impact on RES-induced cell killing, the killing was evidently caspase-independent. In addition, RES treatment of TRAMP-C1, TRAMP-C2, and TRAMP-C3 cells caused an appreciable breakage of genomic DNA into low-molecular-weight fragments.

These findings show that, in inhibition of proliferation of TRAMP cells, RES induces mitochondria-mediated, caspase-independent apoptosis. Therefore, RES may be utilized as a therapeutic agent to control the proliferation and growth of cancer cells.

Visualization and Inhibition of Mitochondria-Nuclear Translocation of Apoptosis Inducing Factor by a Graphene Oxide-DNA Nanosensor

High concentrations of oxidized low density lipoprotein (oxLDL) induce aberrant apoptosis of vascular smooth muscle cells (VSMCs) in atherosclerotic plaques. This apoptosis cannot be blocked completely by the inhibition of caspase, and it eventually potentiates plaque disruption and risk for cardiovascular disease. Given the important role of apoptosis inducing factor (AIF) in caspase-independent apoptosis, here we develop an AIF-targeting nanosensor by the assembly of graphene oxide (GO) nanosheets and dye-labeled DNA hybrid structures. This nanosensor selectively localizes in the cytosol of VSMCs, where it exhibits a "turn-off" fluorescence signal. Under oxLDL stimuli, the release of AIF from mitochondria into cytosol liberates the DNA hybrid structures from the surface of GO and results in a "turn-on" fluorescence signal. This nanosensor is shown to possess rapid response, high sensitivity, and selectivity for AIF that enables real-time imaging of AIF translocation in VSMCs. Using this novel nanosensor, a better assessment of the apoptotic level of VSMCs and a more accurate evaluation of the extent of atherosclerotic lesions can be obtained. More importantly, the abundant binding between DNA hybrid structures and AIF inhibits the translocation of AIF into the nucleus and subsequent apoptosis in VSMCs. This inhibition may help stabilize plaque and reduce the risk of heart attack and stroke.

Pulmonary delivery systems for polyphenols

This review reports on the beneficial pharmacological properties of naturally occurring polyphenols for the treatment of inflammatory pulmonary diseases. In addition, it presents an overview of the different types of inhalable formulations which have been developed in order to achieve efficient delivery of polyphenols to the respiratory tract. The main biological activities of polyphenols (anti-oxidant and anti-inflammatory) are covered, with particular emphasis on the studies describing their therapeutic effects on different factors and conditions characteristic of lung pathologies. Special focus is on the technological aspects which influence the pulmonary delivery of drugs. The various polyphenol-based inhalable formulations reported in the literature are examined with specific attention to the preparation methodologies, aerosol performance, lung deposition and in vitro and in vivo polyphenol uptake by the pulmonary epithelial cells.

Resveratrol inhibits adventitial fibroblast proliferation and induces cell apoptosis through the SIRT1 pathway

Atherosclerosis is one of the most important causes of cardiovascular disease and studies have showed that adventitial fibroblasts, which are considered to be the most common cell type of the vascular adventitia, are involved in the development of early atherosclerotic plaques. Resveratrol is a plant polyphenolic compound confirmed to have anti‑atherosclerotic and cardioprotective effects. The aim of the present study was to investigate the effects of resveratrol on adventitial fibroblasts in vitro and to clarify the underlying mechanism. Adventitial fibroblasts were isolated from the thoracic aorta of 8‑week‑old SPF Sprague‑Dawley rats. Following pre‑treatment with different concentrations of resveratrol, cell viability, DNA synthesis ability, cell apoptosis and cell migration ability were assessed in vitro. Through transfection with small interfering (si)RNA targeting sirtuin 1 (SIRT1), the role of the SIRT1 pathway in these processes was evaluated. Western blot analysis was used to assess the protein expression of SIRT1. It was demonstrated that resveratrol inhibited the cell viability, DNA synthesis and migratory ability of the adventitial fibroblasts, and induced cell apoptosis in a concentration‑dependent manner in vitro. These effects were partly through the SIRT1 pathways. siRNA targeting SIRT1 successfully reversed the antiproliferative, antimigratory and pro‑apoptotic effects of resveratrol on adventitial fibroblasts. In conclusion, the data showed that resveratrol inhibited cell viability, DNA synthesis and cell migration, and induced cell apoptosis in the rat adventitial fibroblasts in vitro through the SIRT1 signaling pathway. As the activation and migration of adventitial fibroblasts contributes to the early development of atherosclerosis, this may be a mechanism underlying the anti‑atherosclerotic effect of resveratrol.

Unraveling the Anticancer Effect of Curcumin and Resveratrol

Resveratrol and curcumin are natural products with important therapeutic properties useful to treat several human diseases, including cancer. In the last years, the number of studies describing the effect of both polyphenols against cancer has increased; however, the mechanism of action in all of those cases is not completely comprehended. The unspecific effect and the ability to interfere in assays by both polyphenols make this challenge even more difficult. Herein, we analyzed the anticancer activity of resveratrol and curcumin reported in the literature in the last 11 years, in order to unravel the molecular mechanism of action of both compounds. Molecular targets and cellular pathways will be described. Furthermore, we also discussed the ability of these natural products act as chemopreventive and its use in association with other anticancer drugs.

The Enhancement of Radiation Sensitivity in Nasopharyngeal Carcinoma Cells via Activation of the Rac1/NADPH Signaling Pathway

We reported in an earlier study that using mass spectrometry and bioinformatic analysis demonstrated Rac1 protein might be mostly mitochondrial target in the radiosensitization process of nasopharyngeal carcinoma CNE-1 cells. The goal of our current study was to reveal the relationship between Rac1/NADPH pathway and radiosensitization in CNE-1 cells using Rac1 activator, phorbol 12-myristate 13-acetate (PMA) and Rac1 inhibitor NSC23766. The Rac1-GTP expression was determined using a pulldown assay, the Rac1 location using a immunofluorescence with a laser scanning confocal microscope, the NADPH oxidase activity with NBT assay and the reactive oxygen species with DCFH-DA probe. The apoptosis rate was analyzed by flow cytometry, and the expressions of p67(phox) and NFκB-p105/p50 were analyzed by Western blot. After treatment with PMA and 2 Gy radiation (compared to the control), Rac1-GTP was activated and translocated to the cell membrane. NADPH oxidase activity, reactive oxygen species of intracellular concentration and the apoptosis rate increased significantly. The expression of p67(phox) and NFκB-p50 protein also increased. However, in the cells treated with NSC23766 alone or NSC23766 combined with 2 Gy irradiation, the results were just the opposite. Overall, these results indicate that the Rac1 protein may be the key target involved in the radiosensitization of nasopharyngeal carcinoma cells. The activated Rac1/NADPH pathway combined with radiation can increase the radiosensitivity of nasopharyngeal carcinoma cells, and the Rac1/NADPH pathway may be the signaling pathway involved in the radiosensitization process.

Anti-tumor effects and cellular mechanisms of resveratrol

Resveratrol (3, 5, 4'-trihydroxystilbene) is a phytoalexin contained in a variety of plants, such as grapes, berries and especially in the dried roots of Polygonum cuspidatum Sieb. et Zucc. It has been shown to exhibit anti-oxidative and anti-inflammation activity, and to reverse the effects of aging. Its ability to suppress cell proliferation, induce apoptosis and suppress the metastasis and invasion in a number of cell lines has prompted a large interest from people for its use as an anti-tumor component. In this review, evidence of resveratrol's anti-tumor effects and molecular mechanisms are recapitulated. First, we present the anti-apoptosis, anti-invasion/metastasis and anti-inflammation effect of resveratrol; second, the main signaling pathways involved in these activities are described and summarized with the studies of different tumors involved. Resveratrol not only induces apoptosis of tumor cells through intrinsic/extrinsic pathways and cell cycle arrest, but also inhibits the invasion and metastasis abilities of tumors via modulating collagen degradation-related molecular targets. Altogether, the present findings suggest the anti-tumor potential of resveratrol against various types of cancers.

Maslinic acid induces mitochondrial apoptosis and suppresses HIF-1α expression in A549 lung cancer cells under normoxic and hypoxic conditions

The apoptotic effects of maslinic acid (MA) at 4, 8, 16, 32 and 64 μmol/L on human lung cancer A549 cells under normoxic and hypoxic conditions were examined. MA at 4–64 and 16–64 μmol/L lowered Bcl-2 expression under normoxic and hypoxic conditions, respectively (p < 0.05). This agent at 4–64 μmol/L decreased Na⁺-K⁺-ATPase activity and increased caspase-3 expression under normoxic conditions, but at 8–64 μmol/L it caused these changes under hypoxic conditions (p < 0.05). MA up-regulated caspase-8, cytochrome c and apoptosis-inducing factor expression under normoxic and hypoxic conditions at 8–64 μmol/L and 32–64 μmol/L, respectively (p < 0.05). MA down-regulated hypoxia-inducible factor (HIF)-1α, vascular endothelial growth factor (VEGF), survivin and inducible nitric oxide synthase (iNOS) expression under normoxic and hypoxic conditions at 8–64 and 16–64 μmol/L, respectively (p < 0.05). After cells were pre-treated with YC-1, an inhibitor of HIF-1α, MA failed to affect the protein expression of HIF-1α, VEGF, survivin and iNOS (p > 0.05). MA at 8-64 and 32-64 μmol/L reduced reactive oxygen species and nitric oxide levels under both conditions (p < 0.05). These findings suggest that maslinic acid, a pentacyclic triterpenic acid, exerted its cytotoxic activities toward A549 cells by mediating mitochondrial apoptosis and the HIF-1α pathway.

Spectral measurement of acceptor-to-donor extinction coefficient ratio in living cells

This report presents a simple method named as sp-ECR to determine the molar extinction coefficient ratio (γ(λex)) of acceptor-to-donor in living cells at excitation wavelength λex, which is closely associated with the acceptor cross-excitation, the hardest issue of FRET quantification. sp-ECR determines γ(λex) by spectrally unmixing the emission spectrum of a donor-acceptor tandem construct under λex excitation without any additional references, such that this method can be performed under optimal imaging condition. We used sp-ECR to measure the γ(458) of Venus/Cerulean in living HepG2 cells on a confocal microscope, and the measured values were consistent with those obtained by lux-FRET method. We also used sp-ECR to measure the γ(458) values of Venus/Cerulean and YFP/CFP as well as YFP/GFP, the commonly used FRET FPs pairs in other two kinds of cancer cell lines on the confocal microscope, and found that the extinction coefficients of FPs depended on cell lines. After predetermining the γ(458) of Venus to ECFP, we used sp-ECR method to monitor the staurosporine (STS)-induced dynamical caspase-3 activation in single live A549 cells expressing SCAT3 by spectrally resolving the absolute FRET efficiency of SCAT3, and found that STS-induced caspase-3 activation in single cells is a very rapid process within 20 min.

The effects of bioactive compounds from plant foods on mitochondrial function: a focus on apoptotic mechanisms

Mitochondria are essential organelles for cellular integrity and functionality maintenance and their imparement is implicated in the development of a wide range of diseases, including metabolic, cardiovascular, degenerative and hyperproliferative pathologies. The identification of different compounds able to interact with mitochondria for therapeutic purposes is currently becoming of primary importance. Indeed, it is well known that foods, particularly those of vegetable origin, present several constituents with beneficial effects on health. This review summarizes and updates the most recent findings concerning the mechanisms through which different dietary compounds from plant foods affect mitochondria functionality in healthy and pathological in vitro and in vivo models, paying particular attention to the pathways involved in mitochondrial biogenesis and apoptosis.

Implications of Bit1 and AIF overexpressions in esophageal squamous cell carcinoma

Overwhelming evidence has demonstrated that Bit1 and AIF as mitochondrial proteins are implicated in the development and progression of a variety of tumors. However, their expressions and biological functions in esophageal squamous cell carcinoma (ESCC) remain to be delineated. In the present study, we found that Bit1, AIF, and Bcl-2 levels in ESCC tissues were significantly higher than those in normal esophageal epithelial tissues and dysplasia tissues (P < 0.05). Stepwise investigation demonstrated that Bit1 and Bcl-2 levels were both tightly associated with lymphatic metastasis and TNM staging (P < 0.05), and the levels of Bit1 mRNA as well as AIF and Bcl-2 proteins were both closely related to tumor differentiation (P < 0.05), but not related to the patients' age and gender (P > 0.05). Importantly, Bit1 mRNA and protein levels in ESCC with lymphatic metastasis and TNM staging in III and IV were markedly higher than that without lymphatic metastasis and TMN staging in I and II. Further analysis showed that expression of Bit1 protein was both positively correlated with expressions of AIF and Bcl-2 proteins (r = 0.408 and 0.405, respectively; P < 0.05). Correctively, our data cited earlier suggest that Bit1 plays pivotal roles in the development and progression of ESCC, and its biological functions in ESCC may be closely associated with AIF and Bcl-2 levels.

Cd-induced apoptosis through the mitochondrial pathway in the hepatopancreas of the freshwater crab Sinopotamon henanense

Cd is one of the most common pollutants in the environment that also induces the apoptosis. To explore the mechanism of apoptosis in the hepatopancreas, freshwater crab S. henanense were treated with 0, 3.56, 7.12, 14.25, 28.49 and 56.98 mg/L Cd for 72 h. Apoptosis was noticeable in every treatment group and necrosis was observed clearly in the high concentration Cd groups. Classical apoptotic bodies were found by transmission electronic microscopy, which revealed chromatin condensation under nuclear membrane and mitochondrial membrane rupture. An increasing number of autolysosomes, damaged rough endoplamic reticulum and Golgi complex were observed as the Cd concentration increase. Brown colored apoptotic cells were detected by the TUNEL test in all Cd-treatment groups. The apoptosis index increased following the elevation of Cd concentration and got 32.9% in the highest Cd group. Caspase-9 and caspase-3 activities increased in the lower Cd treatment groups but no changes in the higher Cd concentration groups (comparing to the control group). The activity of caspase-8 did not change significantly. No significant change in the content of mitochondrial cytochrome c (cyt c) in Cd exposed groups except the decrease in the 56.98 mg/L group. In crabs treated with 3.56, 7.12 and 14.25 mg/L Cd, hyperpolarization of mitochondrial membrane potential (Δψ_m) significantly increased. These results implied that apoptosis in the hepatopancreas induced by Cd occurrs through the mitochondrial caspase-dependent pathway. However, whether there are other apoptotic pathways needs to be studied further.

Attenuation of arsenic retention by resveratrol in lung of arsenic trioxide-exposed rats

Arsenic trioxide (As2O3) is an important environmental toxin. In this study, the effect of resveratrol on As2O3-induced lung injury in rats is evaluated. The results showed that pre-treatment with resveratrol protected As2O3-induced lung injury by the maintenance of glutathione redox system and decrease in arsenic retention. These suggest supplement with resveratrol may alleviate lung injury in the individuals with chronic exposure to arsenic.

LukS-PV induces mitochondrial-mediated apoptosis and G0/G1 cell cycle arrest in human acute myeloid leukemia THP-1 cells

The S component (LukS-PV) is one of the two components of Panton-Valentine leukocidin (PVL), which is a pore-forming cytotoxin secreted by Staphylococcus aureus, with the ability to lyse leukocytes. In this study, LukS-PV had the ability to induce apoptosis in the human acute myeloid leukemia (AML) cell line THP-1. Therefore, we investigated the mechanisms of LukS-PV-induced apoptosis in THP-1 cells. THP-1 cells treated with LukS-PV, resulted in a significant inhibition of proliferation in a dose- and time-dependent manner, and induced G0/G1 arrest associated with an inhibition of cell cycle arrest regulatory protein (cyclin D1) in a dose- and time-dependent manner, as measured by flow cytometry (FCM). After 12h exposure to LukS-PV (1.00 μM), annexin V-EGFP/propidium iodide (PI) FCM revealed that 19.5±3.6% of THP-1 cells were apoptotic, and terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) staining also revealed THP-1 cells were apoptotic. Chip analysis of 84 apoptosis-related genes demonstrated that 9 genes were up-regulated at least 2-fold and that 5 genes were down-regulated at least 2-fold in the treatment group when compared with levels in the control group. Western blotting reveled that the expression of caspase-8 increased significantly (approximately 4-fold). The levels of caspase-9, -3 and Bax increased significantly, and levels of Bcl-2 decreased rapidly with LukS-PV treatment. These data suggest that LukS-PV acts as an anti-leukemia agent and activates AML cell apoptosis via the mitochondrial pathway. Therefore, LukS-PV may be a multi-targeting drug candidate for the prevention and therapy of AML.

Pulmonary metabolism of resveratrol: in vitro and in vivo evidence

The role of pulmonary metabolism in trans-resveratrol (RES) pharmacokinetics was studied in a mouse model. Plasma concentrations of RES and its major metabolites trans-resveratrol-3-sulfate (R3S) and trans-resveratrol-3-glucuronide (R3G) were compared after administration of RES by intravenous (IV) and intra-arterial (IA) routes. Total area under the curve (AUC) of RES decreased by approximately 50% when RES was administered by the IV route compared with the IA route. The AUC of R3G was also significantly higher in mice administered RES by the IV route compared with the IA route. In vitro studies performed with mouse and human lung fractions confirmed pulmonary metabolism of RES. Interestingly, mouse-lung fractions gave rise to both R3S and R3G, whereas human lung fractions yielded R3S. This indicates marked interspecies variation in RES conjugation, especially in the context of extrapolating rodent data to humans. Taken together, the results presented here underline, for the first time, the impact of pulmonary metabolism on resveratrol pharmacokinetics and interspecies differences in RES pulmonary metabolism.

Effect of resveratrol on oxygen consumption by Philasterides dicentrarchi, a scuticociliate parasite of turbot

The phytoalexin resveratrol (RESV) displays antiparasitic activity against Philasterides dicentrarchi, a scuticociliate pathogen of turbot, and causes oxidative stress, inhibition of antioxidant enzyme activity and morphological alterations in the parasite mitochondria. In this study, we analysed the mitochondrial biology of P. dicentrarchi and assessed the effect of RESV on mitochondrial metabolism. We found that RESV caused dose-dependent inhibition of mitochondrial electron transport and O₂ consumption in ciliates permeabilized with digitonin. Although the RESV molecule has a high capacity for antiradical and antioxidant activity, it induced a high level of pro-oxidant activity against the ciliate, thus causing a significant increase in intracellular ROS production. The increased ROS production was accompanied by mitochondrial collapse and dysfunction of mitochondrial membrane potential (ΔΨm) and by a significant increase in intracellular Ca⁺² levels. RESV inhibited parasite growth in a similar way to antimycin A, an inhibitor of mitochondrial electron transport and ROS generator. The findings confirm the mitochondria as a target in the potential development of effective antiparasitic treatments.

Resveratrol induces apoptosis via a Bak-mediated intrinsic pathway in human lung adenocarcinoma cells

Our recent study have shown that resveratrol (RV), a natural plant polyphenol found in red grape skins as well as other food product, induced apoptosis via the downstream factors, caspase-independent AIF and to lesser extent caspase-9, of intrinsic apoptosis pathway in human lung adenocarcinoma (ASTC-a-1) cells. This report is designed to explore the roles of the upstream mediators of the intrinsic pathway, such as Bak/Bax, Bim, Puma and Noxa, during RV-induced apoptosis in human lung adenocarcinoma (ASTC-a-1 and A549) cell lines. RV treatment remarkably induced the activation of Bak but not Bax, and silencing Bak but not Bax by shRNA almost completely prevented RV-induced cell death, mitochondrial dysfunction and also largely prevented RV-induced AIF release, demonstrating the preferential engagement of Bak but not Bax during RV-induced apoptosis. In addition, although RV treatment induced a significant degradation of Mcl-1, knockdown of Mcl-1 by shRNA only modestly increased RV-induced Bak activation. Interestingly, silencing Bim but not Puma and Noxa remarkably attenuated RV-induced cell death, loss of mitochondrial membrane potential, and Bak activation, suggesting the important roles of Bim. Collectively, our findings for the first time demonstrate that RV induces apoptosis dominantly via a Bak- but not Bax-mediated AIF-dependent mitochondrial apoptotic signaling pathway in which Bim but not Puma and Noxa may supply the force to trigger Bak activation and subsequent apoptosis in both ASTC-a-1 and A549 cell lines.