The combination of TRAIL and isoflavones enhances apoptosis in cancer cells

Santin (5,7-Dihydroxy-3,6,4'-Trimetoxy-Flavone) Enhances TRAIL-Mediated Apoptosis in Colon Cancer Cells

TRAIL (Tumor necrosis factor-Related Apoptosis-Inducing Ligand) has the ability to selectively kill cancer cells without being toxic to normal cells. This endogenous ligand plays an important role in surveillance and anti-tumor immunity. However, numerous tumor cells are resistant to TRAIL-induced apoptosis. In this study, the apoptotic effect of santin in combination with TRAIL on colon cancer cells was examined. Flow cytometry was used to detect the apoptosis and expression of death receptors (TRAIL-R1/DR4 and TRAIL-R2/DR5). Mitochondrial membrane potential (ΔΨm) was evaluated by DePsipher staining with the use of fluorescence microscopy. We have shown for the first time that flavonoid santin synergizes with TRAIL to induce apoptosis in colon cancer cells. Santin induced TRAIL-mediated apoptosis through increased expression of death receptors TRAIL-R1 and TRAIL-R2 and augmented disruption of the mitochondrial membrane in SW480 and SW620 cancer cells. The obtained data may indicate the potential role of santin in colon cancer chemoprevention through the enhancement of TRAIL-mediated apoptosis.

Metabolites Identification and Mechanism Prediction of Neobavaisoflavone In Vitro and In Vivo of Rats through UHPLC-Q-Exactive Plus Orbitrap MS Integrated Network Pharmacology

Neobavaisoflavone is an important isoflavone component isolated from Psoraleae Fructus. It is used extensively worldwide because of its antibacterial, antioxidant, anti-inflammatory, anticancer, and anti-osteoporotic activities. However, there is no systematic and comprehensive research on the metabolism of neobavaisoflavone in vivo and in vitro. The study aimed to analyze the metabolic characteristics and mechanism of neobavaisoflavone for the first time. Firstly, biological samples were pretreated by the solid-phase extraction (SPE) method, methanol precipitation, and acetonitrile precipitation. Secondly, the samples were analyzed on UHPLC-Q-Exactive Plus Orbitrap MS. Thirdly, metabolites were tentatively identified based on retention time, parallel reaction monitoring strategy, diagnostic product ions, and neutral loss fragments. A total of 72 metabolites of neobavaisoflavone were tentatively identified, including 28 in plasma, 43 in urine, 18 in feces, six in the liver, and four in the liver microsome. The results suggested that neobavaisoflavone mainly underwent glucuronidation, sulfation, hydroxylation, methylation, cyclization, hydration, and their composite reactions in vivo and in vitro. In addition, nine active components with high bioavailability and 191 corresponding targets were predicted by the Swiss Drug Design database. The 1806 items of GO and 183 KEGG signaling pathways were enriched. These results showed that metabolites expanded the potential effects of neobavaisoflavone. The present study would provide the scientific basis for the further exploitation and application of neobavaisoflavone.

The modulating effect of methoxy-derivatives of 2'-hydroxychalcones on the release of IL-8, MIF, VCAM-1 and ICAM-1 by colon cancer cells

Colon cancer is one of the leading causes of death in the world. The search for effective and minimally invasive methods of treating colon cancer is the aim of modern medicine. Chalcones and their derivatives have shown an anticancer activity. The aim of the study was to evaluate the effect of methoxy-derivatives of 2'-hydroxychalcones: 2'-hydroxy-3"-methoxychalcone (TJ3), 2'-hydroxy-2"-methoxychalcone (TJ6) and 2'-hydroxy-4"-metoxychalcone (TJ7) at the concentrations of 10 µM and 25 µM on the release of IL-8, MIF, VCAM-1, ICAM-1 by colon cancer SW480 and SW620 cell lines. The cytokines and adhesion molecules were detected using the Bio-Plex Magnetic Luminex Assay and the Bio-Plex Suspension Array System. Our results showed that all tested methoxy-derivatives of 2'-hydroxychalcone compounds significantly reduced ICAM-1 released by SW480 cancer cells. The tested compounds at both concentrations did not significantly affect VCAM-1 released by SW480 and SW620 cancer cell lines. All methoxy-derivatives significantly reduced the concentration of MIF in dose dependent manner on SW480 cells. The TJ3 at the concentration of 25 µM significantly decreased IL-8 secreted by SW480 and SW620 cancer cells. Our results demonstrated that tested methoxy-derivatives of 2'-hydroxychalcones showed modulating effect on colon cancer cells.

Mechanisms and therapeutic prospects of polyphenols as modulators of the aryl hydrocarbon receptor

Polyphenolic AhR modulators displayed concentration-, XRE-, gene-, species- and cell-specific agonistic/antagonistic activity.

Sequestering survivin to functionalized nanoparticles: a strategy to enhance apoptosis in cancer cells

Survivin belongs to the family of inhibitor of apoptosis proteins (IAP) and is present in most cancers while being below detection limits in most terminally differentiated adult tissues, making it an attractive protein to target for diagnostic and, potentially, therapeutic roles. Sub-100 nm poly(propargyl acrylate) (PA) particles were surface modified through the copper-catalyzed azide/alkyne cycloaddition of an azide-terminated survivin ligand derivative (azTM) originally proposed by Abbott Laboratories and speculated to bind directly to survivin (protein) at its dimer interface. Using affinity pull-down studies, it was determined that the PA/azTM nanoparticles selectively bind survivin and the particles can enhance apoptotic cell death in glioblastoma cell lines and other survivin over-expressing cell lines such as A549 and MCF7 relative to cells incubated with the original Abbott-derived small molecule inhibitor.

Delphinidin sensitizes prostate cancer cells to TRAIL-induced apoptosis, by inducing DR5 and causing caspase-mediated HDAC3 cleavage

TRAIL can induce apoptosis in some cancer cells and is an immune effector in the surveillance and elimination of developing tumors. Yes, some cancers are resistant to TRAIL. Delphinidin, a polyphenolic compound contained in brightly colored fruits and vegetables, has anti-inflammatory, anti-oxidant, and anti-tumorigenic activities. Here we showed that delphinidin sensitized TRAIL-resistant human prostate cancer cells to undergo apoptosis. Cells treated with delphinidin and TRAIL activated the extrinsic and intrinsic pathways of caspase activation. TRAIL-induced apoptosis in prostate cancer cells pretreated with delphinidin was dependent on death receptor 5 (DR5) and downstream cleavage of histone deacetylase 3 (HDAC3). In conclusion, delphinidin sensitizes prostate cancer cells to TRAIL-induced apoptosis by inducing DR5, thus causing caspase-mediated HDAC3 cleavage. Our data reveal a potential way of chemoprevention of prostate cancer by enabling TRAIL-mediated apoptosis.

MLK3 is a direct target of biochanin A, which plays a role in solar UV-induced COX-2 expression in human keratinocytes

Solar UV (sUV) is an important environmental carcinogen. Recent studies have shown that sUV is associated with numerous human skin disorders, such as wrinkle formation and inflammation. In this study, we found that the isoflavone, biochanin A, inhibited the expression of sUV-induced COX-2, which is a well-characterized sUV-induced enzyme, in both human HaCaT keratinocytes and JB6 P+ mouse skin epidermal cells. Several studies have demonstrated the beneficial effects of biochanin A. However, its direct molecular target is unknown. We found that biochanin A inhibited sUV-induced phosphorylation of MKK4/JNK/c-Jun and MKK3/6/p38/MSK1. Mixed-lineage kinase 3 (MLK3) is an upstream kinase of MKK4 and MKK3/6. Thus, we evaluated the effect of biochanin A on MLK3. We found that sUV-induced MLK3 phosphorylation was not affected, whereas MLK3 kinase activity was significantly suppressed by biochanin A. Furthermore, direct binding of biochanin A in the MLK3 ATP-binding pocket was detected using pull-down assays. Computer modeling supported our observation that MLK3 is a novel target of biochanin A. These results suggest that biochanin A exerts chemopreventive effects by suppressing sUV-induced COX-2 expression mediated through MLK3 inhibition.

Polyphenols Isolated from Propolis Augment TRAIL-Induced Apoptosis in Cancer Cells

Epidemiological data support the concept that phenols and polyphenols in diet are safe and nontoxic, and have long-lasting beneficial effects on human health. The potential target for complementary and alternative medicine (CAM) research has been on the discovery of natural compounds that can be used in the prevention and treatment of cancer. Propolis is one of the richest sources of plant phenolics (flavonoids and phenolic acids). The ethanolic extract of propolis (EEP) and its polyphenols possess immunomodulatory, chemopreventive, and antitumor effects. Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is a  naturally occurring anticancer agent that preferentially induces apoptosis in cancer cells and is not toxic to normal cells. Endogenous TRAIL plays a significant role in immunosurveillance and defense against cancer cells. However, as more tumor cells are reported to be resistant to TRAIL-mediated death, it is important to develop new strategies to overcome this resistance. EEP and polyphenols isolated from propolis have been shown to sensitize cancer cells to TRAIL-induced apoptosis. In this paper we demonstrate for the first time the crucial role of the main phenolics isolated from propolis in enhancing TRAIL-mediated death in tumor cells for cancer chemoprevention.

Taxifolin enhances andrographolide-induced mitotic arrest and apoptosis in human prostate cancer cells via spindle assembly checkpoint activation

Andrographolide (Andro) suppresses proliferation and triggers apoptosis in many types of cancer cells. Taxifolin (Taxi) has been proposed to prevent cancer development similar to other dietary flavonoids. In the present study, the cytotoxic and apoptotic effects of the addition of Andro alone and Andro and Taxi together on human prostate carcinoma DU145 cells were assessed. Andro inhibited prostate cancer cell proliferation by mitotic arrest and activation of the intrinsic apoptotic pathway. Although the effect of Taxi alone on DU145 cell proliferation was not significant, the combined use of Taxi with Andro significantly potentiated the anti-proliferative effect of increased mitotic arrest and apoptosis by enhancing the cleavage of poly(ADP-ribose) polymerase, and caspases-7 and -9. Andro together with Taxi enhanced microtubule polymerization in vitro, and they induced the formation of twisted and elongated spindles in the cancer cells, thus leading to mitotic arrest. In addition, we showed that depletion of MAD2, a component in the spindle assembly checkpoint (SAC), alleviated the mitotic block induced by the two compounds, suggesting that they trigger mitotic arrest by SAC activation. This study suggests that the anti-cancer activity of Andro can be significantly enhanced in combination with Taxi by disrupting microtubule dynamics and activating the SAC.

Targeting death receptor TRAIL-R2 by chalcones for TRAIL-induced apoptosis in cancer cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in cancer cells without toxicity to normal cells. TRAIL binds to death receptors, TRAIL-R1 (DR4) and TRAIL-R2 (DR5) expressed on cancer cell surface and activates apoptotic pathways. Endogenous TRAIL plays an important role in immune surveillance and defense against cancer cells. However, as more tumor cells are reported to be resistant to TRAIL mediated death, it is important to search for and develop new strategies to overcome this resistance. Chalcones can sensitize cancer cells to TRAIL-induced apoptosis. We examined the cytotoxic and apoptotic effects of TRAIL in combination with four chalcones: chalcone, isobavachalcone, licochalcone A and xanthohumol on HeLa cancer cells. The cytotoxicity was measured by MTT and LDH assays. The apoptosis was detected using annexin V-FITC staining by flow cytometry and fluorescence microscopy. Death receptor expression was analyzed using flow cytometry. The decreased expression of death receptors in cancer cells may be the cause of TRAIL-resistance. Chalcones enhance TRAIL-induced apoptosis in HeLa cells through increased expression of TRAIL-R2. Our study has indicated that chalcones augment the antitumor activity of TRAIL and confirm their cancer chemopreventive properties.

Synthetic flavanones augment the anticancer effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is considered as the most promising anticancer agent in the TNF superfamily because of its selective cytotoxicity against tumor cells versus normal primary cells. However, as more tumor cells are reported to be resistant to TRAIL-mediated death, it is important to develop new therapeutic strategies to overcome this resistance. Flavonoids have been shown to sensitize cancer cells to TRAIL-induced apoptosis. The aim of this study was to examine the cytotoxic and apoptotic activities of TRAIL on HeLa cancer cells in combination with two synthetic compounds: 6-hydroxyflavanone (6-HF) and its derivative 6-propionoxy-flavanone (6-PF) and to determine the mechanism by which the flavanones overcome the TRAIL-resistance. The cytotoxicity was measured by MTT and LDH assays. The apoptosis was detected by annexin V-FITC fluorescence staining in flow cytometry and microscopy. Death receptor (TRAIL-R1/DR4 and TRAIL-R2/DR5) expression were analysed using flow cytometry. Mitochondrial membrane potential was evaluated using DePsipher staining by fluorescence microscopy. The synthetic flavanones enhanced TRAIL-induced apoptosis in HeLa cells through increased expression of TRAIL-R2 death receptor and reduction of mitochondrial membrane potential. Our study indicates that the 6-HF and 6-PF augmented the anticancer effects of TRAIL and confirm a potential use of flavanones in TRAIL-based anticancer therapy and prevention.

Artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) sensitizes LNCaP prostate cancer cells to TRAIL-induced apoptosis

Naturally occurring phenolic compounds have been shown to sensitize prostate cancer cells to tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. TRAIL is a potent stimulator of apoptosis in cancer cells and an important immune effector molecule in the surveillance and elimination of developing tumours. However, many cancer cells are resistant to TRAIL-mediated death. In this study, we aimed to determine the mechanisms by which TRAIL resistance can be overcome in prostate cancer cells by 3,5-diprenyl-4-hydroxycinnamic acid (artepillin C). Artepillin C is a bioactive component of Brazilian green propolis that possesses antitumour and chemopreventive activities. TRAIL-resistant LNCaP prostate cancer cells were treated with TRAIL and artepillin C. Cytotoxicity was measured by MTT and lactate dehydrogenase (LDH) assays. Apoptosis was detected using Annexin V-FITC staining by flow cytometry and fluorescence microscopy. Death receptor (DR) (TRAIL-R1/DR4 and TRAIL-R2/DR5) expression was analyzed using flow cytometry. Mitochondrial membrane potential (ΔΨm) was evaluated using DePsipher staining by fluorescence micro scopy. The inhibition of NF-κB (p65) activation was confirmed with the ELISA-based TransAM NF-κB kit. Caspase-8 and caspase-3 activities were determined by colorimetric protease assays. The results showed that artepillin C sensitized the TRAIL-resistant LNCaP cells by engaging the extrinsic (receptor-mediated) and intrinsic (mitochondrial) apoptotic pathways. Artepillin C increased the expression of TRAIL-R2 and decreased the activity of NF-κB. Co-treatment with TRAIL and artepillin C induced the significant activation of caspase-8 and caspase-3, as well as the disruption of ΔΨm. These findings show that prostate cancer cells can be sensitized to TRAIL-mediated immunoprevention by artepillin C and confirm the role of phenolic compounds in prostate cancer immunochemoprevention.

The coumarin psoralidin enhances anticancer effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)

Coumarins are a very common type of secondary plant metabolites with a broad spectrum of biological activities. Psoralidin is a naturally occurring furanocoumarin isolated from Psoralea corylifolia possessing anticancer and chemopreventive properties. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers apoptosis in cancer cells with no toxicity toward normal tissues. Endogenous TRAIL plays an important role in immune surveillance and defence against cancer cells. Coumarins can modulate TRAIL-mediated apoptosis in cancer cells. We examined the cytotoxic and apoptotic activities of psoralidin in combination with TRAIL on HeLa cancer cells. The cytotoxicity was measured by MTT and LDH assays. The apoptosis was detected using annexin V-FITC staining and mitochondrial membrane potential was evaluated using DePsipher staining by fluorescence microscopy. Death receptor (TRAIL-R1/DR4 and TRAIL-R2/DR5) expression was analyzed using flow cytometry. Psoralidin enhanced TRAIL-induced apoptosis in HeLa cells through increased expression of TRAIL-R2 death receptor and depolarization of mitochondrial membrane potential. Our study indicated that psoralidin augmented the anticancer effects of TRAIL and confirmed a potential use of coumarins in cancer chemoprevention.

Chlorin-based photodynamic therapy enhances the effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in bladder cancer cells

Background

Photodynamic therapy (PDT) is an attractive, emerging therapeutic procedure suitable for the treatment of non-muscle-invasive bladder cancer. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a death ligand that belongs to the TNF superfamily of cytokines. The ability of TRAIL to selectively induce apoptosis in cancer cells but not in normal cells promotes the development of TRAIL-based cancer therapy. However, many tumor cells are resistant to TRAIL-induced apoptosis. The purpose of the study was to overcome TRAIL-resistance in bladder cancer cells by photodynamic therapy (PDT).

Material/Methods

Three human bladder transitional cancer cell lines – T24, 647V and SW780 – were treated with TRAIL and/or chlorin-based PDT. The cytotoxicity was measured by MTT and LDH assays and apoptosis was detected using annexin V by flow cytometry.

Results

Our test confirmed that T24 and 647V bladder cancer cells are resistant to TRAIL, whereas SW780 cells are sensitive to TRAIL. Then we examined the cytotoxic and apoptotic effects of TRAIL in combination with chlorin e6-polyvinylpyrrolidone (Ce6-PVP)-mediated PDT on bladder cancer cells. We showed for the first time that pretreatment with a low dose of PDT significantly sensitizes bladder cancer cells to TRAIL-induced apoptosis. Chlorin-based PDT augments the effect of TRAIL on bladder cancer cells.

Conclusions

PDT with Ce6-PVP photosensitizer enhances the cytotoxic and apoptotic effects of TRAIL on bladder cancer cells. The obtained results suggest that combined treatment by TRAIL and PDT may provide the basis for a new therapeutic approach to induce cell death in bladder cancer.

Natural polyphenols in cancer therapy

Natural polyphenols are secondary metabolites of plants involved in defense against different types of stress. Extracts containing these compounds have been used for thousands of years in traditional eastern medicine. Polyphenols act on multiple targets in pathways and mechanisms related to carcinogenesis, tumor cell proliferation and death, inflammation, metastatic spread, angiogenesis, or drug and radiation resistance. Nevertheless, reported effects claimed for polyphenols are controversial, since correlations between in vitro effects and in vivo evidence are poorly established. The main discrepancy between health claims versus clinical observations is the frequent use of nonphysiologically relevant concentrations of these compounds and their metabolites in efficacy and mechanistic studies. The present review will discuss how in vivo administration correlates with polyphenol metabolism, toxicity, and bioavailability. Analysis of the general application of polyphenols in cancer therapy will be complemented by potential applications in the therapy of specific tumors, including melanoma, colorectal and lung cancers. Possible pharmaceutical formulations, structural modifications, combinations, and delivery systems aimed to increase bioavailability and/or biological effects will be discussed. Final remarks will include recommendations for future research and developments.

Red clover and soy isoflavones--an in vitro safety assessment

Isoflavones from red clover and soy plant extracts are used in highly concentrated food supplements as an alternative to hormone replacement therapy. Due to their estrogenic activity, isoflavones are a focus of safety concerns about their potential to promote the growth of hormone-dependent cancer cells. In this study, isoflavones and plant extracts were tested for their effect on cell proliferation, apoptosis induction and cell cycle arrest. Isoflavones and plant extracts were applied in proliferation assays on 11 human cancer cell lines (representing cancers of the colon, prostate, breast, cervix, liver, pancreas, stomach and ovaries) and a fibroblast line to detect cytotoxic activity. Fluorescence-activated cell sorting was used to detect the induction of apoptosis or cell cycle arrest. Isoflavones and plant extracts significantly reduced the proliferation activity of the treated cancer cell lines. Growth promotion was not observed, but apoptosis or necrosis induction was, as was cell cycle arrest, with genistein as the most potent isoflavone. Isoflavones and plant extracts from soy and red clover, respectively, do not promote the growth of human cancer cells but induce decreased cell proliferation, increased apoptosis and cell cycle arrest. These results indicate that isoflavones can be considered safe compounds.

Effect of ALA-mediated photodynamic therapy in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on bladder cancer cells

INTRODUCTION

Photodynamic therapy (PDT), an alternative treatment modality for superficial bladder tumors is based on the interaction of a photosensitizer with light. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising candidate for anticancer therapy due to its ability to selectively induce apoptosis in cancer cells. However, not all tumor cells are sensitive to TRAIL. TRAIL-resistant cancer cells can be sensitized to TRAIL induced apoptosis by anticancer agents.

OBJECTIVE

We investigated the combined cytotoxic effect of TRAIL and PDT with 5-aminolevulinic acid (ALA) on bladder cancer cells.

MATERIALS AND METHODS

THREE HUMAN BLADDER TRANSITIONAL CANCER CELL LINES: T24, 647V, and SW780 were treated with TRAIL and/or ALA-mediated PDT. Cytotoxicity was determined by MTT and LDH assay.

RESULTS

Our study confirmed that T24 and 647V bladder cancer cells were resistant to TRAIL, whereas SW780 cells were sensitive to TRAIL. We therefore examined the cytotoxic effect of TRAIL in combination with ALA-mediated PDT on bladder cancer cells. We showed for the first time that pretreatment with low dose of PDT significantly sensitizes bladder cancer cells to TRAIL induced cytotoxicity.

CONCLUSION

ALA-mediated PDT augments the cytotoxic effect of TRAIL on transitional cancer cells of bladder. The obtained results suggest that combined treatment of TRAIL and PDT may provide the basis for a new strategy to induce cytotoxicity in bladder cancer cells.

Effects of phytochemicals on ionization radiation-mediated carcinogenesis and cancer therapy

Ionizing radiation (IR)-induced cellular damage is implicated in carcinogenesis as well as therapy of cancer. Advances in radiation therapy have led to the decrease in dosage and localizing the effects to the tumor; however, the development of radioresistance in cancer cells and radiation toxicity to normal tissues are still the major concerns. The development of radioresistance involves several mechanisms, including the activation of mitogenic and survival signaling, induction of DNA repair, and changes in redox signaling and epigenetic regulation. The current strategy of combining radiation with standard cytotoxic chemotherapeutic agents can potentially lead to unwanted side effects due to both agents. Thus agents are needed that could improve the efficacy of radiation killing of cancer cells and prevent the damage to normal cells and tissues caused by the direct and bystander effects of radiation, without have its own systemic toxicity. Chemopreventive phytochemicals, usually non-toxic agents with both cancer preventive and therapeutic activities, could rightly fit in this approach. In this regard, naturally occurring compounds, including curcumin, parthenolide, genistein, gossypol, ellagic acid, withaferin, plumbagin and resveratrol, have shown considerable potential. These agents suppress the radiation-induced activation of receptor tyrosine kinases and nuclear factor-κB signaling, can modify cell survival and DNA repair efficacy, and may potentiate ceramide signaling. These radiosensitizing and counter radioresistance mechanisms of phytochemicals in cancer cells are also associated with changes in epigenetic gene regulation. Because radioresistance involves multiple mechanisms, more studies are needed to discover novel phytochemicals having multiple mechanisms of radiosensitization and to overcome radioresistance of cancer cells. Pre-clinical studies are needed to address the appropriate dosage, timing, and duration of the application of phytochemicals with radiation to justify clinical trials. Nonetheless, some phytochemicals in combination with IR may play a significant role in enhancing the therapeutic index of cancer treatment.

The dietary isoflavone biochanin-A sensitizes prostate cancer cells to TRAIL-induced apoptosis

Biochanin-A, a major dietary isoflavone in soy and red clover, possesses anticancer and chemopreventive properties. Induction of apoptosis by naturally occurring dietary agents is an important event for cancer chemoprevention. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers apoptosis selectively in cancer cells but not in normal cells. Soluble or expressed in immune cells, molecules TRAIL plays a significant role in surveillance and defense mechanisms against tumours. Prostate cancer is an ideal disease for nutritional prevention. The TRAIL-mediated apoptosis pathway in prostate cancer cells is an attractive target for chemopreventive activities of dietary agents. LNCaP and DU145 prostate cancer cells are resistant to TRAIL-induced apoptosis. We showed that biochanin-A markedly augmented TRAIL-induced cytotoxicity and apoptosis in both prostate cancer cell lines. Then, we investigated the mechanisms by which biochanin-A enhanced TRAIL-mediated apoptosis using the LNCaP cell line. The isoflavone sensitized the TRAIL-resistant LNCaP cells through the inhibition of transcription factor NF-κB(p65) activity, increased the expression of the death receptor TRAIL-R2 (DR5), and disrupted mitochondrial membrane potential (ΔΨm). Our study confirmed that biochanin-A overcame TRAIL-resistance by engaging both intrinsic and extrinsic apoptotic pathways and by regulating the NF-κB activity. The results suggested a potential role of biochanin-A in prostate cancer chemoprevention through the enhancement of TRAIL-mediated apoptosis.

Enhanced TRAIL-mediated apoptosis in prostate cancer cells by the bioactive compounds neobavaisoflavone and psoralidin isolated from Psoralea corylifolia

Numerous compounds detected in medical plants and dietary components or supplements possess chemopreventive, antitumor and immunomodulatory properties. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an important endogenous anticancer factor that induces apoptosis selectively in cancer cells. However, some tumor cells are resistant to TRAIL-mediated apoptosis. Naturally occurring agents could sensitize TRAIL-resistant cancer cells and augment their apoptotic activity.We examined the cytotoxic and apoptotic effects of neobavaisoflavone and psoralidin in combination with TRAIL on LNCaP prostate cancer cells. The cytotoxicity was evaluated by MTT and LDH assays. The apoptosis was detected using Annexin V-FITC by flow cytometry and fluorescence microscopy. The LNCaP cells were shown to be resistant to TRAIL-induced apoptosis. Our study demonstrated that neobavaisoflavone and psoralidin sensitized TRAIL-resistant cells and markedly augmented TRAIL-mediated apoptosis and cytotoxicity in prostate cancer cells. Cotreatment of LNCaP cells with 100 ng/ml TRAIL and 50 μM neobavaisoflavone or 50 μM psoralidin increased the percentage of the apoptotic cells to 77.5±0.5% or 64.4±0.5%, respectively. The data indicate the potential role of the bioactive compounds isolated from the medicinal plant Psoralea corylifolia (neobavaisoflavone and psoralidin) in prostate cancer chemoprevention through enhancement of TRAIL-mediated apoptosis.

Inhibition of inflammatory mediators by neobavaisoflavone in activated RAW264.7 macrophages

Flavonoids and coumarins are the major bioactive constituents identified in Psoralea corylifolia. The active fraction isolated from fruits, seeds and roots possesses antibacterial, antioxidative and immunomodulatory properties. Neobavaisoflavone is one of the flavonoids found in Psoralea corylifolia. In the present study we investigated in vitro the anti-inflammatory activity of neobavaisoflavone. Macrophages play an important role in inflammation through the release of inflammatory mediators involved in the immune response. Inappropriate and prolonged macrophage activation is largely responsible for the pathology of acute and chronic inflammatory conditions. Neobavaisoflavone significantly inhibited the production of reactive oxygen species (ROS), reactive nitrogen species (RNS) and cytokines: IL-1β, IL-6, IL-12p40, IL-12p70, TNF-α in LPS+IFN-γ– or PMA– stimulated RAW264.7 macrophages.

Chalcones and dihydrochalcones augment TRAIL-mediated apoptosis in prostate cancer cells

Chalcones and dihydrochalcones exhibit chemopreventive and antitumor activity. TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) is a natural endogenous anticancer agent. We examined the cytotoxic and apoptotic effect of chalcones and dihydrochalcones on TRAIL-mediated apoptosis in LNCaP prostate cancer cells. The cytotoxicity was evaluated by the MTT and LDH assays. The apoptosis was detected using annexin V-FITC by flow cytometry and fluorescence microscopy. The DeltaPsim was evaluated using DePsipher staining by fluorescence microscopy. Our study showed that two tested chalcones (chalcone and 2',6'dihydroxy-4'-methoxychalcone) and three dihydrochalcones (2',6'-dihydroxy-4'4-dimethoxydihydrochalcone, 2',6'-dihydroxy-4'-methoxydihydro- chalcone, and 2',4',6'-trihydroxydihydrochalcone, called phloretin) markedly augmented TRAIL-induced apoptosis and cytotoxicity in LNCaP cells and confirmed the significant role of chalcones in chemoprevention of prostate cancer.