Curcumin-induced apoptosis in PC3 prostate carcinoma cells is caspase-independent and involves cellular ceramide accumulation and damage to mitochondria

Effects of curcumin and ursolic acid in prostate cancer: A systematic review

The major barriers to phytonutrients in prostate cancer therapy are non-specific mechanisms and bioavailability issues. Studies have pointed to a synergistic combination of curcumin (CURC) and ursolic acid (UA). We investigate this combination using a systematic review process to assess the most likely mechanistic pathway and human testing in prostate cancer. We used the PRISMA statement to screen titles, abstracts, and the full texts of relevant articles and performed a descriptive analysis of the literature reviewed for study inclusion and consensus of the manuscript. The most common molecular and cellular pathway from articles reporting on the pathways and effects of CURC (n = 173) in prostate cancer was NF-κB (n = 25, 14.5%). The most common molecular and cellular pathway from articles reporting on the pathways and effects of UA (n = 24) in prostate cancer was caspase 3/caspase 9 (n = 10, 41.6%). The three most common molecular and cellular pathway from articles reporting on the pathways and effects of both CURC and UA (n = 193) in prostate cancer was NF-κB (n = 28, 14.2%), Akt (n = 22, 11.2%), and androgen (n = 19, 9.6%). Therefore, we have identified the potential synergistic target pathways of curcumin and ursolic acid to involve NF-κB, Akt, androgen receptors, and apoptosis pathways. Our review highlights the limited human studies and specific effects in prostate cancer.

Impact of curcumin on p38 MAPK: therapeutic implications

Curcumin (diferuloylmethane) is a herbal remedy which possesses numerous biological attributes including anti-inflammatory, anti-oxidant and anti-cancer properties. Curcumin has been shown to impact a number of signaling pathways including nuclear factor kappa B (NF-KB), reactive oxygen species (ROS), Wingless/Integrated (Wnt), Janus kinase-signal transducer and activator of mitogen-activated protein kinase (MAPK) and transcription (JAK/STAT). P38 belongs to the MAPKs, is known as a stress-activated MAPK and is involved in diverse biological responses. P38 is activated in various signaling cascades. P38 plays a role in inflammation, cell differentiation, proliferation, motility and survival. This cascade can serve as a therapeutic target in many disorders. Extensive evidence confirms that curcumin impacts the P38 MAPK signaling pathway, through which it exerts anti-inflammatory, neuroprotective, and apoptotic effects. Hence, curcumin can positively affect inflammatory disorders and cancers, as well as to increase glucose uptake in cells. This review discusses the pharmacological and therapeutic effects of curcumin as effected through p38 MAPK.

Phytochemicals in Inhibition of Prostate Cancer: Evidence from Molecular Mechanisms Studies

Prostate cancer is one of the leading causes of death for men worldwide. The development of resistance, toxicity, and side effects of conventional therapies have made prostate cancer treatment become more intensive and aggressive. Many phytochemicals isolated from plants have shown to be tumor cytotoxic. In vitro laboratory studies have revealed that natural compounds can affect cancer cell proliferation by modulating many crucial cellular signaling pathways frequently dysregulated in prostate cancer. A multitude of natural compounds have been found to induce cell cycle arrest, promote apoptosis, inhibit cancer cell growth, and suppress angiogenesis. In addition, combinatorial use of natural compounds with hormone and/or chemotherapeutic drugs seems to be a promising strategy to enhance the therapeutic effect in a less toxic manner, as suggested by pre-clinical studies. In this context, we systematically reviewed the currently available literature of naturally occurring compounds isolated from vegetables, fruits, teas, and herbs, with their relevant mechanisms of action in prostate cancer. As there is increasing data on how phytochemicals interfere with diverse molecular pathways in prostate cancer, this review discusses and emphasizes the implicated molecular pathways of cell proliferation, cell cycle control, apoptosis, and autophagy as important processes that control tumor angiogenesis, invasion, and metastasis. In conclusion, the elucidation of the natural compounds' chemical structure-based anti-cancer mechanisms will facilitate drug development and the optimization of drug combinations. Phytochemicals, as anti-cancer agents in the treatment of prostate cancer, can have significant health benefits for humans.

Bioassay-Guided Isolation of 2-[p-(2-Carboxyhydrazino)phenoxy]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol from Oroxylum indicum and the Investigation of Its Molecular Mechanism Action of Apoptosis Induction

The leaf crude extract of Oroxylum indicum (L.) Kurz induces genomic DNA fragmentation, comet formation, and the inhibition of cell proliferation in the prostate cancer cell line PC3, as assessed by agarose gel electrophoresis, comet assay and MTT assay, respectively. The bioactive compound was purified through bioassay-guided fractionation using preparative HPLC and MTT assay. The light brown and water-soluble compound was characterized using 1H and 13C nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR), and electrospray ionization (ESI) mass spectrometry. The compound was identified as a glycosylated hydroquinone derivative, 2-[p-(2-Carboxyhydrazino)phenoxy]-6-(hydroxymethyl) tetrahy-dro-2H-pyran-3,4,5-triol (molecular formula, C13H18N2O8; molecular mass = 330). The identified phytocompound has not been reported earlier elsewhere. Therefore, the common name of the novel anticancer phytocompound isolated from Oroxylum indicum in this current study is oroxyquinone. The half-maximal inhibitory concentration (IC₅₀) of oroxyquinone on PC3 cells was 58.9 µM (95% CI = 54.5 to 63.7 µM). Treatment of PC3 cells with oroxyquinone induced genomic DNA fragmentation and chromatin condensation, increased in the annexin-V positive cells, arrested the cell cycle at S phases, and inhibited the cell migration; as assessed by comet assay, DAPI staining, flow cytometry and a wound healing assay, respectively. On the investigation of the molecular mechanism of the induction of apoptosis, the results indicated that oroxyquinone induced caspase-3 and PARP independent apoptosis but through the p38 pathway and the localization of AIF into the nucleus. The present study identifies a novel anticancer molecule and provides scientific evidence supporting the therapeutic potency of Oroxylum indicum for ethnomedicinal uses.

Ebselen, a multi-target compound: its effects on biological processes and diseases

Ebselen is a well-known synthetic compound mimicking glutathione peroxidase (GPx), which catalyses some vital reactions that protect against oxidative damage. Based on a large number of in vivo and in vitro studies, various mechanisms have been proposed to explain its actions on multiple targets. It targets thiol-related compounds, including cysteine, glutathione, and thiol proteins (e.g., thioredoxin and thioredoxin reductase). Owing to this, ebselen is a unique multifunctional agent with important effects on inflammation, apoptosis, oxidative stress, cell differentiation, immune regulation and neurodegenerative disease, with anti-microbial, detoxifying and anti-tumour activity. This review summarises the current understanding of the multiple biological processes and molecules targeted by ebselen, and its pharmacological applications.

Exploring Nanoemulsions for Prostate Cancer Therapy

Prostate carcinoma is typical cancer. It is the second most common cancer globally. The estimated new cases in 2020 was 191 930 and estimated deaths was 33 330. Age, family history, & genetic factors are major factors that drive prostate cancer. Although, for treating metastatic disease, the major therapies available are radiation,bisphosphonate, and palliative chemotherapy. But the major drawback is therapy is disease-driven and later becomes metastatic and requires treatment. The ability to revolutionize cancer treatment by major targeting vehicles via the exploration of nanoemulsion suggests a potential for cancer treatment. The unique property of a biphasic liquid dosage form called nanoemulsion to reach leaky tumor vasculature is due to its nano-meter oil-droplet size of 20-200 nm. Recent reporting on nanoemulsions disclose their embracing and lay alternative for re-purposing herbal and synthetic drugs and their combination especially for targeting prostate cancer formulating an obtainable nanomedicine. So, this article emphasizes the use of nanoemulsions incorporating therapeutic agents for successful and targeted delivery for prostate cancer.

Dimethoxycurcumin reduces proliferation and induces apoptosis in renal tumor cells more efficiently than demethoxycurcumin and curcumin

Curcumin (Cur), is a pigment with antiproliferative activity but has some pharmacokinetic limitations, which led researchers to look for more effective structure analogs. This work investigated the effects of Cur and compared them with the two analogs, demethoxycurcumin (DeMC) and dimethoxycurcumin (DiMC), to elucidate their mechanisms of action. The cytotoxic, antiproliferative, and genotoxic effects these compounds were correlated based on gene expression analysis in the human renal adenocarcinoma cells (786-O). Cur decreased CYP2D6 expression and exhibited cytotoxic effects, such as inducing monopolar spindle formation and mitotic arrest mediated by the increase in CDKN1A (p21) mRNA. This dysregulation induced cell death through a caspase-independent pathway but was mediated by decrease in MTOR and BCL2 mRNA expression, suggesting that apoptosis occurred by autophagy. DeMC and DiMC had similar effects in that they induced monopolar spindle and mitotic arrest, were genotoxic, and activated GADD45A, an important molecule in repair mechanisms, and CDKN1A. However, the induction of apoptosis by DeMC was delayed and regulated by the decrease of antiapoptotic mRNA BCL.XL and subsequent activation of caspase 9 and caspase 3/7. DiMC treatment increased the expression of CYP1A2, CYP2C19, and CYP3A4 and exhibited higher cytotoxicity compared with other compounds. It induced apoptosis by increasing mRNA expression of BBC3, MYC, and CASP7 and activation of caspase 9 and caspase 3/7. These data revealed that different gene regulation processes are involved in cell death induced by Cur, DeMC, and DiMC. All three can be considered as promising chemotherapy candidates, with DiMC showing the greatest potency.

ASC-J9® suppresses prostate cancer cell proliferation and invasion via altering the ATF3-PTK2 signaling

BACKGROUND

Early studies indicated that ASC-J9®, an androgen receptor (AR) degradation enhancer, could suppress the prostate cancer (PCa) progression. Here we found ASC-J9® could also suppress the PCa progression via an AR-independent mechanism, which might involve modulating the tumor suppressor ATF3 expression.

METHODS

The lentiviral system was used to modify gene expression in C4-2, CWR22Rv1 and PC-3 cells. Western blot and Immunohistochemistry were used to detect protein expression. MTT and Transwell assays were used to test the proliferation and invasion ability.

RESULTS

ASC-J9® can suppress PCa cell proliferation and invasion in both PCa C4-2 and CWR22Rv1 cells via altering the ATF3 expression. Further mechanistic studies reveal that ASC-J9® can increase the ATF3 expression via decreasing Glutamate-cysteine ligase catalytic (GCLC) subunit expression, which can then lead to decrease the PTK2 expression. Human clinical studies further linked the ATF3 expression to the PCa progression. Preclinical studies using in vivo mouse model also proved ASC-J9® could suppress AR-independent PCa cell invasion, which could be reversed after suppressing ATF3.

CONCLUSIONS

ASC-J9® can function via altering ATF3/PTK2 signaling to suppress the PCa progression in an AR-independent manner.

A novel TGF-β receptor II mutation (I227T/N236D) promotes aggressive phenotype of oral squamous cell carcinoma via enhanced EGFR signaling

Background

Transforming growth factor-β (TGF-β) signaling is a double-edged sword in cancer development and progression. TGF-β signaling plays a tumor suppressive role during the early stages of tumor development but promotes tumor progression in later stages. We have previously identified various mutations of TGF-β receptor II (TβRII) in human oral squamous cell carcinoma (OSCC) samples. In the present study we analyzed I227T/N236D mutation of TβRII, which was detected in the metastatic lymph node of an OSCC patient.

Methods

The effect of I227T/N236D TβRII mutation on transcriptional activities was measured using DR26 cells, which lack functional TβRII. HSC2 human OSCC cells stably expressing wild-type and I227T/N236D mutant TβRII were generated and used to examine the effect of I227T/N236D TβRII mutation on xenograft tumor growth, in vitro cell proliferation, apoptosis, migration, and invasion.

Results

The I227T/N236D mutation of TβRII upregulated TGF-β signaling and promoted xenograft tumor growth when compared with the wild-type, without affecting the in vitro proliferative capacities. To delineate the differences in proliferative capacities in vivo and in vitro, the apoptotic and survival signals were analyzed following curcumin treatment. Concomitant with apoptotic induction, epidermal growth factor receptor (EGFR) activation was observed upon curcumin treatment, which was further activated in I227T/N236D mutant transfectant cells when compared with wild-type cells. Enhanced EGFR activation correlated with cell survival and apoptotic resistance. Enhanced migratory and invasive capabilities of I227T/N236D mutant cells also depended on EGFR signaling.

Conclusions

These results suggest that enhanced EGFR signaling via upregulated TGF-β signaling shifted the balance toward survival and promoted cell migration and invasion in I227T/N236D mutant cells, elucidating the role of I227T/N236D mutation of TβRII in OSCC progression.

Curcumin against Prostate Cancer: Current Evidence

Cancer is a condition characterized by remarkably enhanced rates of cell proliferation paired with evasion of cell death. These deregulated cellular processes take place following genetic mutations leading to the activation of oncogenes, the loss of tumor suppressor genes, and the disruption of key signaling pathways that control and promote homeostasis. Plant extracts and plant-derived compounds have historically been utilized as medicinal remedies in different cultures due to their anti-inflammatory, antioxidant, and antimicrobial properties. Many chemotherapeutic agents used in the treatment of cancer are derived from plants, and the scientific interest in discovering plant-derived chemicals with anticancer potential continues today. Curcumin, a turmeric-derived polyphenol, has been reported to possess antiproliferative and proapoptotic properties. In the present review, we summarize all the in vitro and in vivo studies examining the effects of curcumin in prostate cancer.

Lajis N, Abas F, Othman I, Naidu R. Mechanism of Anti-Cancer Activity of Curcumin on Androgen-Dependent and Androgen-Independent Prostate Cancer

Prostate cancer (PCa) is a heterogeneous disease and ranked as the second leading cause of cancer-related deaths in males worldwide. The global burden of PCa keeps rising regardless of the emerging cutting-edge technologies for treatment and drug designation. There are a number of treatment options which are effectively treating localised and androgen-dependent PCa (ADPC) through hormonal and surgery treatments. However, over time, these cancerous cells progress to androgen-independent PCa (AIPC) which continuously grow despite hormone depletion. At this particular stage, androgen depletion therapy (ADT) is no longer effective as these cancerous cells are rendered hormone-insensitive and capable of growing in the absence of androgen. AIPC is a lethal type of disease which leads to poor prognosis and is a major contributor to PCa death rates. A natural product-derived compound, curcumin has been identified as a pleiotropic compound which capable of influencing and modulating a diverse range of molecular targets and signalling pathways in order to exhibit its medicinal properties. Due to such multi-targeted behaviour, its benefits are paramount in combating a wide range of diseases including inflammation and cancer disease. Curcumin exhibits anti-cancer properties by suppressing cancer cells growth and survival, inflammation, invasion, cell proliferation as well as possesses the ability to induce apoptosis in malignant cells. In this review, we investigate the mechanism of curcumin by modulating multiple signalling pathways such as androgen receptor (AR) signalling, activating protein-1 (AP-1), phosphatidylinositol 3-kinases/the serine/threonine kinase (PI3K/Akt/mTOR), wingless (Wnt)/ß-catenin signalling, and molecular targets including nuclear factor kappa-B (NF-κB), B-cell lymphoma 2 (Bcl-2) and cyclin D1 which are implicated in the development and progression of both types of PCa, ADPC and AIPC. In addition, the role of microRNAs and clinical trials on the anti-cancer effects of curcumin in PCa patients were also reviewed.

Curcumin stimulates exosome/microvesicle release in an in vitro model of intracellular lipid accumulation by increasing ceramide synthesis

Curcumin, a hydrophobic polyphenol found in the rhizome of Curcuma longa, has been shown to reduce intracellular lipid accumulation in mouse models of lysosomal storage diseases such as Niemann-Pick type C. Exosomes are small extracellular vesicles secreted by cells in response to changes in intracellular ceramide composition. Curcumin can induce exosome/microvesicle release in cellular models of lipid deposition; however, the mechanism by which curcumin stimulates this release is unknown. In a model of lipid trafficking impairment in C6 glia cells, we show that curcumin stimulated ceramide synthesis by increasing the intracellular concentration of ceramide-dihydroceramide. Ceramide overload increased exosome/microvesicle secretion 10-fold, thereby reducing the concentration of lipids in the endolysosomal compartment. These effects were blocked by inhibitors of serine palmitoyltransferase (myriocin) and ceramide synthase (fumonisin B1). It is concluded that the decrease in intracellular lipid deposition induced by curcumin is mediated by increased ceramide synthesis and exosome/microvesicle release. This action may represent an additional health benefit of curcumin.

Evaluating the Anti-cancer Efficacy of a Synthetic Curcumin Analog on Human Melanoma Cells and Its Interaction with Standard Chemotherapeutics

Melanoma is the leading cause of skin-cancer related deaths in North America. Metastatic melanoma is difficult to treat and chemotherapies have limited success. Furthermore, chemotherapies lead to toxic side effects due to nonselective targeting of normal cells. Curcumin is a natural product of Curcuma longa (turmeric) and has been shown to possess anti-cancer activity. However, due to its poor bioavailability and stability, natural curcumin is not an effective cancer treatment. We tested synthetic analogs of curcumin that are more stable. One of these derivatives, Compound A, has shown significant anti-cancer efficacy in colon, leukemia, and triple-negative inflammatory breast cancer cells. However, the effects of Compound A against melanoma cells have not been studied before. In this study, for the first time, we demonstrated the efficacy of Compound A for the selective induction of apoptosis in melanoma cells and its interaction with tamoxifen, taxol, and cisplatin. We found that Compound A induced apoptosis selectively in human melanoma cells by increasing oxidative stress. The anti-cancer activity of Compound A was enhanced when combined with tamoxifen and the combination treatment did not result in significant toxicity to noncancerous cells. Additionally, Compound A did not interact negatively with the anti-cancer activity of taxol and cisplatin. These results indicate that Compound A could be developed as a selective and effective melanoma treatment either alone or in combination with other non-toxic agents like tamoxifen.

Mechanisms of apoptosis modulation by curcumin: Implications for cancer therapy

Cancer incidences are growing and cause millions of deaths worldwide. Cancer therapy is one of the most important challenges in medicine. Improving therapeutic outcomes from cancer therapy is necessary for increasing patients' survival and quality of life. Adjuvant therapy using various types of antibodies or immunomodulatory agents has suggested modulating tumor response. Resistance to apoptosis is the main reason for radioresistance and chemoresistance of most of the cancers, and also one of the pivotal targets for improving cancer therapy is the modulation of apoptosis signaling pathways. Apoptosis can be induced by intrinsic or extrinsic pathways via stimulation of several targets, such as membrane receptors of tumor necrosis factor-α and transforming growth factor-β, and also mitochondria. Curcumin is a naturally derived agent that induces apoptosis in a variety of different tumor cell lines. Curcumin also activates redox reactions within cells inducing reactive oxygen species (ROS) production that leads to the upregulation of apoptosis receptors on the tumor cell membrane. Curcumin can also upregulate the expression and activity of p53 that inhibits tumor cell proliferation and increases apoptosis. Furthermore, curcumin has a potent inhibitory effect on the activity of NF-κB and COX-2, which are involved in the overexpression of antiapoptosis genes such as Bcl-2. It can also attenuate the regulation of antiapoptosis PI3K signaling and increase the expression of MAPKs to induce endogenous production of ROS. In this paper, we aimed to review the molecular mechanisms of curcumin-induced apoptosis in cancer cells. This action of curcumin could be applicable for use as an adjuvant in combination with other modalities of cancer therapy including radiotherapy and chemotherapy.

Cancer Prevention and Therapy with Polyphenols: Sphingolipid-Mediated Mechanisms

Polyphenols, chemically characterized by a polyhydroxylated phenolic structure, are well known for their widespread pharmacological properties: anti-inflammatory, antibiotic, antiseptic, antitumor, antiallergic, cardioprotective and others. Their distribution in food products is also extensive especially in plant foods such as vegetables, cereals, legumes, fruits, nuts and certain beverages. The latest scientific literature outlines a resilient interconnection between cancer modulation and dietary polyphenols by sphingolipid-mediated mechanisms, usually correlated with a modification of their metabolism. We aim to extensively survey this relationship to show how it could be advantageous in cancer treatment or prevention by nutrients. From this analysis it emerges that a combination of classical chemotherapy with nutrients and especially with polyphenols dietary sources may improve efficacy and decreases negative side effects of the antineoplastic drug. In this multifaceted scenario, sphingolipids play a pivotal role as bioactive molecules, emerging as the mediators of cell proliferation in cancer and modulator of chemotherapeutics.

Interdiction of Sphingolipid Metabolism Revisited: Focus on Prostate Cancer

Sphingolipid metabolism is known to play a role in cell death, survival, and therapy resistance in cancer. Sphingolipids, particularly dihydroceramide and ceramide, are associated with antiproliferative or cell death responses, respectively, and are central to effective cancer therapy. Within the last decade, strides have been made in elucidating many intricacies of sphingolipid metabolism. New information has emerged on the mechanisms by which sphingolipid metabolism is dysregulated during malignancy and how cancer cells survive and/or escape therapeutic interventions. This chapter focuses on three main themes: (1) sphingolipid enzymes that are dysregulated in cancer, particularly in prostate cancer; (2) inhibitors of sphingolipid metabolism that antagonize prosurvival responses; and (3) sphingolipid-driven escape mechanisms that allow cancer cells to evade therapies. We explore clinical and preclinical approaches to interdict sphingolipid metabolism and provide a rationale for combining strategies to drive the generation of antiproliferative ceramides with prevention of ceramide clearance.

Curcumin-Conjugated Gold Clusters for Bioimaging and Anticancer Applications

Curcumin-conjugated gold clusters (CUR-AuNCs) were synthesized using a "green" procedure and utilized as an anticancer and a bioimaging agent. Curcumin is a well-known anticancer agent, which forms a cluster when reacting with a gold precursor under mild alkali condition. A fluorescence spectroscopy analysis showed that the CUR-AuNCs emitted red fluorescence (650 nm) upon visible light (550) irradiation. Fourier transform infrared spectroscopy analysis confirmed the stretching and bending nature between the gold atoms and curcumin. Meanwhile, transmission electron microscopy analysis showed a cluster of approximately 1-3 nm with a uniform size. Time-resolved fluorescence analysis demonstrated that the red fluorescence was highly stable. Moreover, laser confocal imaging and atomic force microscopy analysis illustrated that a cluster was well distributed in the cell. This cluster exhibited less toxicity in the mortal cell line (COS-7) and high toxicity in the cervical cancer cell line (HeLa). The results demonstrated the conjugation of curcumin into the fluorescent gold cluster as a potential material for anticancer therapy and bioimaging applications.

Effects of demethoxycurcumin on the viability and apoptosis of skin cancer cells

The present study investigated the effects and mechanisms of demethoxycurcumin (DMC) on a human skin squamous cell carcinoma cell line, A431, and a human keratinocyte cell line, HaCaT. A431 and HaCaT cells were cultured in vitro. The effects of DMC treatment on cell viability were analyzed using the Cell Counting kit‑8 (CCK‑8) assay; cell cycle distribution was analyzed by flow cytometry; apoptosis was assessed by flow cytometry and Hoechst 33258 staining; and the protein expression levels of cytochrome c, B‑cell lymphoma 2 (Bcl‑2), Bcl‑2‑associated X protein (BAX), caspase‑9 and caspase‑3 were evaluated by western blotting. CCK‑8 assay results demonstrated that DMC treatment significantly inhibited viability of A431 and HaCaT cells in a dose‑dependent manner. Flow cytometric analysis confirmed that DMC treatment induced apoptosis in a dose‑dependent manner, and significantly increased the proportion of cells in G2/M phase. Western blot analysis indicated that the protein expression levels of Bcl‑2 were decreased, whereas the expression levels of BAX, caspase‑9, caspase‑3 and cytochrome c were increased following DMC treatment compared with in untreated cells. In conclusion, DMC treatment significantly inhibited viability of A431 and HaCaT cells, and induced cell cycle arrest in G2/M phase. The present study indicated that DMC may induce apoptosis of skin cancer cells through a caspase‑dependent pathway.

Selective Targeting of Cancer Cells by Oxidative Vulnerabilities with Novel Curcumin Analogs

Recently, research has focused on targeting the oxidative and metabolic vulnerabilities in cancer cells. Natural compounds like curcumin that target such susceptibilities have failed further clinical advancements due to the poor stability and bioavailability as well as the need of high effective doses. We have synthesized and evaluated the anti-cancer activity of several monocarbonyl analogs of curcumin. Interestingly, two novel analogs (Compound A and I) in comparison to curcumin, have increased chemical stability and have greater anti-cancer activity in a variety of human cancer cells, including triple-negative, inflammatory breast cancer cells. In particular, the generation of reactive oxygen species was selective to cancer cells and occurred upstream of mitochondrial collapse and execution of apoptosis. Furthermore, Compound A in combination with another cancer-selective/pro-oxidant, piperlongumine, caused an enhanced anti-cancer effect. Most importantly, Compound A was well tolerated by mice and was effective in inhibiting the growth of human triple-negative breast cancer and leukemia xenografts in vivo when administered intraperitoneally. Thus, exploiting oxidative vulnerabilities in cancer cells could be a selective and efficacious means to eradicate malignant cells as demonstrated by the curcumin analogs presented in this report with high therapeutic potential.

Structure-activity relationship studies of 1,7-diheteroarylhepta-1,4,6-trien-3-ones with two different terminal rings in prostate epithelial cell models

To systematically investigate the structure-activity relationships of 1,7-diheteroarylhepta-1,4,6-trien-3-ones in three human prostate cancer cell models and one human prostate non-neoplastic epithelial cell model, thirty five 1,7-diarylhepta-1,4,6-trien-3-ones with different terminal heteroaromatic rings have been designed for evaluation of their anti-proliferative potency in vitro. These target compounds have been successfully synthesized through two sequential Horner-Wadsworth-Emmons reactions starting from the appropriate aldehydes and tetraethyl (2-oxopropane-1,3-diyl)bis(phosphonate). Their anti-proliferative potency against PC-3, DU-145 and LNCaP human prostate cancer cell lines can be significantly enhanced by the manipulation of the terminal heteroaromatic rings, further demonstrating the utility of 1,7-diarylhepta-1,4,6-trien-3-one as a potential scaffold for the development of anti-prostate cancer agents. The optimal analog 40 is 82-, 67-, and 39-fold more potent than curcumin toward the three prostate cancer cell lines, respectively. The experimental data also reveal that the trienones with two different terminal aromatic rings possess greater potency toward three prostate cancer cell lines, but also have greater capability of suppressing the proliferation of PWR-1E benign human prostate epithelial cells, as compared to the corresponding counterparts with two identical terminal rings and curcumin. The terminal aromatic rings also affect the cell apoptosis perturbation.

Design, synthesis, and biological evaluation of 1,9-diheteroarylnona-1,3,6,8-tetraen-5-ones as a new class of anti-prostate cancer agents

In search of more effective chemotherapeutics for the treatment of castration-resistant prostate cancer and inspired by curcumin analogues, twenty five (1E,3E,6E,8E)-1,9-diarylnona-1,3,6,8-tetraen-5-ones bearing two identical terminal heteroaromatic rings have been successfully synthesized through Wittig reaction followed by Horner-Wadsworth-Emmons reaction. Twenty-three of them are new compounds. The WST-1 cell proliferation assay was employed to assess their anti-proliferative effects toward both androgen-sensitive and androgen-insensitive human prostate cancer cell lines. Eighteen out of twenty-five synthesized compounds possess significantly improved potency as compared with curcumin. The optimal compound, 78, is 14- to 23-fold more potent than curcumin in inhibiting prostate cancer cell proliferation. It can be concluded from our data that 1,9-diarylnona-1,3,6,8-tetraen-5-one can serve as a new potential scaffold for the development of anti-prostate cancer agents and that pyridine-4-yls and quinolin-4-yl act as optimal heteroaromatic rings for the enhanced potency of this scaffold. Two of the most potent compounds, 68 and 75, effectively suppress PC-3 cell proliferation by activating cell apoptosis and by arresting cell cycle in the G0/G1 phase.

Molecular mechanisms of curcumin and its semisynthetic analogues in prostate cancer prevention and treatment

Primary prostate cancer, also known as prostate adenocarcinoma (PCa), is a devastating cancer in men worldwide. Europe and developing countries of Asia have fewer reported cases of prostate cancer compared to increasing cases in the United States with higher incidence in Black men. Risk factors associated with prostate cancer are aging, genetics, lifestyle, high body mass index as well as carcinogenic exposure to carbon-containing fuels, tobacco, and charbroiled meats. Hormone therapy and radical prostatectomy are commonly implemented treatments. The >20.000 prostate cancer deaths of 2013 suggest that there exists a need for enhanced chemopreventive and therapeutic agents for prostate cancer treatment. Fruits, vegetables, and red wines contain high levels of polyphenolic levels. Consumption of these products may provide chemoprevetion of PCa. Curcumin, the major compound from the turmeric rhizome Curcuma longa has long been used for medicinal purposes as an antiseptic and wound healing. This review focuses on curcumin's therapeutic effectiveness in vitro and in vivo in prostate cancer models. The review will highlight the mechanisms of actions of curcumin in the signaling pathways of prostate cancer.

Synthesis and evaluation of 1,7-diheteroarylhepta-1,4,6-trien-3-ones as curcumin-based anticancer agents

Thirty (1E,4E,6E)-1,7-diaryl-1,4,6-heptatrien-3-ones, featuring a central linear trienone linker and two identical nitrogen-containing heteroaromatic rings, were designed and synthesized as curcumin-based anticancer agents on the basis of their structural similarity to the enol-tautomer of curcumin, in addition to taking advantage of the possibly enhanced pharmacokinetic profiles contributed by the basic nitrogen-containing heteroaromatic rings. Their cytotoxicity and antiproliferative activity were evaluated towards both androgen-dependent and androgen-independent prostate cancer cell lines, as well as HeLa human cervical cancer cells. Among them, the ten most potent analogues are 5- to 36-fold more potent than curcumin in inhibiting cancer cell proliferation. The acquired structure-activity relationship data indicate (i) that (1E,4E,6E)-1,7-diaryl-1,4,6-heptatrien-3-ones represent a potential scaffold for development of curcumin-based agents with substantially improved cytotoxicity and anti-proliferative effect; and (ii) 1-alkyl-1H-imidazol-2-yl and 1-alkyl-1H-benzo[d]imidazole-2-yl serve as optimal heteroaromatic rings for increased in vitro potency of this scaffold. Two of most potent compounds displayed no apparent cytotoxicity toward MCF-10A normal mammary epithelial cells at 1 μM concentration. Treatment of PC-3 prostate cancer cells with the most potent compound led to appreciable cell cycle arrest at a G1/G0 phase and cell apoptosis induction.

Marchantin M Induces Apoptosis of Prostate Cancer Cells Through Endoplasmic Reticulum Stress

BACKGROUND Apoptosis is mediated by the endoplasmic reticulum (ER) stress pathway, mitochondrial pathway, and death receptor. Data herein suggested an inhibitory effect of marchantin M on tumor formation in nude mice as well as the impact on CHOP and GRP78 expression. MATERIAL AND METHODS The role of marchantin M on proliferation and apoptosis of DU145 cells were measured by MTT and flow cytometry, respectively. Western blot was applied to detect the expression of GRP78 and CHOP. The mice received abdominal injection at 1 time/2 d and 2 ml/time. Tumor volume was measured every 6 days. The mice were euthanatized 30 days after marchantin injection and tumor weight was measured. Cell apoptosis was determined by TUNEL. The expressions of CHOP and GRP78 were detected by immunohistochemistry. RESULTS Tumor size and weight in marchantin groups were significantly lower than in the control group (A, B) (P<0.05), and the inhibitory rate presented a dose-dependent increase. Compared with controls, the levels of CHOP and GRP78 expression elevated obviously following the treatment with marchantin (P<0.05). It showed statistically significant difference among groups C, D, E, with different levels of apoptosis indexes incremented in groups of marchantin H, M, L, compared with groups A and B (P<0.05). CONCLUSIONS Overall, this study shows that marchantin M circumvents the growth of prostate cancer PC-3 tumor and up-regulates expressions of CHOP and GRP78. Our data also indicate that marchantin M limits the proliferation and favors apoptosis of DU145 cells in a time- and dose-dependent manner.

Curcumin inhibits B[a]PDE-induced procarcinogenic signals in lung cancer cells, and curbs B[a]P-induced mutagenesis and lung carcinogenesis

Benzo[a]pyrene is a procarcinogen present in environment and cigarette smoke, which could be bio-transformed in vivo to B[a]PDE, a potent carcinogen known to form DNA adducts and induce mutations. We observed that curcumin, a known chemopreventive, could significantly inhibit the survival of lung cancer cells exposed to B[a]PDE. It also downregulates B[a]PDE-induced nuclear translocation of NF-κB as assessed by Electrophoretic Mobility Shift Assay (EMSA) and NF-κB-dependent reporter gene assay. Ames assay demonstrated its ability to revert the mutagenic property of benzo[a]pyrene. These observations prompted us to evaluate the efficacy of curcumin in preventing B[a]P-induced lung carcinogenesis in vivo and to explore the molecular mechanism associated with it. The average number of tumor nodules present in the lungs of the Swiss albino mice, which received benzo[a]pyrene, was significantly high compared to that received curcumin as 2% diet along with B[a]P. Curcumin treatment significantly reverted histopathological deviations in the lung tissues due to benzo[a]pyrene ingestion. Moreover, curcumin diet reduced benzo[a]pyrene-induced activation of NF-κB and MAPK signaling and Cox-2 transcription in lung tissues of mice. Taken together, this study illustrates multifaceted efficacy of curcumin in preventing lung cancer.

The Emerging Role of Extracellular Vesicle-Mediated Drug Resistance in Cancers: Implications in Advanced Prostate Cancer

Emerging evidence has shown that the extracellular vesicles (EVs) regulate various biological processes and can control cell proliferation and survival, as well as being involved in normal cell development and diseases such as cancers. In cancer treatment, development of acquired drug resistance phenotype is a serious issue. Recently it has been shown that the presence of multidrug resistance proteins such as Pgp-1 and enrichment of the lipid ceramide in EVs could have a role in mediating drug resistance. EVs could also mediate multidrug resistance through uptake of drugs in vesicles and thus limit the bioavailability of drugs to treat cancer cells. In this review, we discussed the emerging evidence of the role EVs play in mediating drug resistance in cancers and in particular the role of EVs mediating drug resistance in advanced prostate cancer. The role of EV-associated multidrug resistance proteins, miRNA, mRNA, and lipid as well as the potential interaction(s) among these factors was probed. Lastly, we provide an overview of the current available treatments for advanced prostate cancer, considering where EVs may mediate the development of resistance against these drugs.

Inhibitors of dihydroceramide desaturase 1: Therapeutic agents and pharmacological tools to decipher the role of dihydroceramides in cell biology

Dihydroceramide desaturase (Des1) is the last enzyme in the de novo synthesis of ceramides (Cer). It catalyzes the insertion of a double bond into dihydroceramides (dhCer) to convert them to Cer, both of which are further metabolized to more complex (dihydro) sphingolipids. For many years dhCer have received poor attention, mainly due to their supposed lack of biological activity. It was not until about ten years ago that the concept that dhCer might have regulatory roles in biology emerged for the first time. Since then, multiple publications have established that dhCer are implicated in a wide spectrum of biological processes. Physiological and pathophysiological functions of dhCer have been recently reviewed. In this review we will focus on the biochemical features of Des1 and on its inhibition by different compounds with presumably different modes of action.

Ceramide generation during curcumin-induced apoptosis is controlled by crosstalk among Bcl-2, Bcl-xL, caspases and glutathione

Curcumin exhibits anti-cancer properties manifested by activation of pro-apoptotic signaling. We have demonstrated earlier that apoptosis of HL-60 human leukemia cells induced by curcumin is controlled by ceramide generated by neutral sphingomyelinase (nSMase) which contributes to sphingomyelin synthase (SMS) inhibition favoring accumulation of ceramide in cells. Here we report that the activity of nSMase, ceramide accumulation and death of HL-60 cells are inhibited by overexpression of Bcl-xL or Bcl-2 proteins, while down-regulation of nSMase interferes with degradation of Bcl-2 but not Bcl-xL. Activation of nSMase in curcumin-treated cells requires the activity of apoptosis initiator caspase-8 and executioner caspase-3, whereas nSMase depletion prevents activation of caspase-3, but not caspase-8. These data place nSMase activation downstream of caspase-8 and Bcl-xL and indicate a mutual regulation between nSMase and caspase-3 activity on one hand, and Bcl-2 level on the other hand in curcumin-treated cells. The activation of nSMase and ceramide accumulation also depended on the depletion of glutathione. The depletion of glutathione required the activity of caspase-8 and caspase-3 as well as the down-regulation of Bcl-2 and Bcl-xL. Together, the data indicate a crosstalk among Bcl-2, Bc-xL, caspases and glutathione during curcumin-induced apoptosis and point to the superior role of caspase-8 activity, Bcl-xL down-regulation and glutathione depletion in the pro-apoptotic cascade leading to nSMase activation and generation of ceramide.

Curcumin loaded pH-sensitive hybrid lipid/block copolymer nanosized drug delivery systems

Curcumin is a perspective drug candidate with pleiotropic antineoplastic activity, whose exceptionally low aqueous solubility and poor pharmacokinetic properties have hampered its development beyond the preclinical level. A possible approach to overcome these limitations is the encapsulation of curcumin into nano-carriers, incl. liposomes. The present contribution is focused on feasibility of using hybrid pH-sensitive liposomes, whereby curcumin is entrapped as a free drug and as a water soluble inclusion complex with PEGylated tert-butylcalix[4]arene, which allows the drug to occupy both the phospholipid membranes and the aqueous core of liposomes. The inclusion complexes were encapsulated in dipalmithoylphosphathydilcholine:cholesterol liposomes, whose membranes were grafted with a poly(isoprene-b-acrylic acid) diblock copolymer to confer pH-sensitivity. The liposomes were characterized by DLS, ζ-potential measurements, cryo-TEM, curcumin encapsulation efficacy, loading capacity, and in vitro release as a function of pH. Free and formulated curcumin were further investigated for cytotoxicity, apoptosis-induction and caspase-8, and 9 activation in chemosensitive HL-60 and its resistant sublines HL-60/Dox and HL-60/CDDP. Formulated curcumin was superior cytotoxic and apoptogenic agent vs. the free drug. The mechanistic assay demonstrated that the potent proapoptotic effects of pH-sensitive liposomal curcumin presumably mediated via recruitment of both extrinsic and intrinsic apoptotic pathways in both HL-60 and HL-60/CDDP cells.

Redox nanoparticles inhibit curcumin oxidative degradation and enhance its therapeutic effect on prostate cancer

Curcumin is a phytochemical with diverse molecular targets and is well known for its anti-tumor potential. However, it has limited application in cancer therapy because curcumin undergoes rapid oxidative degradation at physiological conditions resulting in poor stability and bio-availability. In this study, we were able to suppress curcumin's oxidative degradation by encapsulating it in a nanoparticle that also acts as a radical scavenger. We prepared curcumin-loaded pH-sensitive redox nanoparticles (RNP(N)) by self-assembling amphiphilic block copolymers conjugated with reactive oxygen species (ROS) scavenging nitroxide radicals to ensure the delivery of minimally degraded curcumin to target regions. In vitro analysis confirmed that the entrapment of both curcumin and nitroxide radicals in the hydrophobic core of RNP(N) suppressed curcumin degradation in conditions mimicking the physiological environment. Evaluation of apoptosis-related molecules in the cells, such as ceramides, caspases, apoptosis-inducing factor, and acid ceramidase revealed that curcumin loaded RNP(N) induced strong apoptosis compared to free curcumin. Lastly, intravenous injection of curcumin loaded RNP(N) suppressed tumor growth in vivo, which is due to the increased bio-availability and significant ROS scavenging at tumor sites. These results demonstrated that RNP(N) is a promising drug carrier with unique ROS-scavenging abilities, and it is able to overcome the crucial hurdle of curcumin's limitations to enhance its therapeutic potential.

A monocarbonyl analogue of curcumin, 1,5-bis(3-hydroxyphenyl)-1,4-pentadiene-3-one (Ca 37), exhibits potent growth suppressive activity and enhances the inhibitory effect of curcumin on human prostate cancer cells

Prostate carcinoma is one of the leading causes of cancer-related morbidity and mortality in males in western countries. Curcumin exhibits growth-suppressive activity against several cancers, including prostate cancer, but it has poor bioavailability. The purpose of this study was to evaluate the anticancer potency and mechanism of a curcumin analogue, 1,5-bis(3-hydroxyphenyl)-1,4-pentadiene-3-one (Ca 37), in human prostate cancer. Studies were performed in established human prostate cancer cell lines (PC-3 and DU145) as well as in a murine xenograft tumor (PC-3) model. Ca 37 presented a preferential suppression capacity against growth and migration toward prostate cancer cells compared with curcumin. Ca 37 impaired the bioenergetics system, promoted cell cycle arrest and apoptosis activation in PC-3 cells. In addition, 0.5 μmol (6.65 mg/kg body weight) of Ca 37 significantly inhibited the growth of the prostate xenografted tumors, whereas 6 μmol (110 mg/kg body weight) of curcumin had little effect. Furthermore, a combination of Ca 37 and curcumin resulted in enhanced antitumor activity in prostate cancer cells. N-Acetylcysteine abrogated both reactive oxygen species (ROS) production and viability loss induced by Ca 37 but partially prevented growth inhibition in PC-3 cells treated with curcumin alone, or a combination with Ca 37. The data indicate that induction of ROS plays a vital role in the growth inhibitory effect of Ca 37 in PC-3 cells. This study suggests that Ca 37, alone or in combination with curcumin, may be a promising anticancer agent for prostate cancer therapy.

Possible relations between oxidative damage and apoptosis in benign prostate hyperplasia and prostate cancer patients

Cancer has been described as the twentieth century plague, and is a very common health problem. It has been reported that ROS and ROS products play a key role in cancer and that oxidative damage is effective in apoptosis initiation. In this study we aimed to evaluate the relationship between MDA (malondialdehyde), DNA damage (8-hydroxyguanine, 8-OH-dG), and caspase-3 in BHP and prostate cancer patients. Twenty male patients with prostate cancer and 20 male patients with benign prostate hyperplasia were included into this study. The MDA (nanomole), DNA damage (nanograms per millilitre), and caspase-3 (nanograms per millilitre) levels were measured in prostate cancer and benign prostate hyperplasia using Elisa kits (Millipore Corporation, Billerica, MA, USA). In the prostate cancer group, serum MDA (30.96 ± 9.25) and DNA damage (4.42 ± 0.36) levels were significantly raised (p < 0.05) when compared to the benign prostate hyperplasia group (24.05 ± 8.06, 3.99 ± 0.54). However, in the prostate cancer group, serum caspase-3 (2.36 ± 0.82) levels were statistically significantly lowered (p < 0.05) compared with the benign prostate hyperplasia group (3.15 ± 1.04). We observed that altered prooxidant, DNA damage levels may lead to an increase in oxidative damage and may consequently play an important role in prostate carcinogenesis. These findings indicate that, although the triggering of these changes is unknown, changes in the levels of MDA, DNA damage, and caspase-3 in the blood are related to prostatic carcinoma development. In addition, it would be appropriate to conduct new studies with a large number of patients at different stages.

The molecular basis for the pharmacokinetics and pharmacodynamics of curcumin and its metabolites in relation to cancer

This review addresses the oncopharmacological properties of curcumin at the molecular level. First, the interactions between curcumin and its molecular targets are addressed on the basis of curcumin's distinct chemical properties, which include H-bond donating and accepting capacity of the β-dicarbonyl moiety and the phenylic hydroxyl groups, H-bond accepting capacity of the methoxy ethers, multivalent metal and nonmetal cation binding properties, high partition coefficient, rotamerization around multiple C-C bonds, and the ability to act as a Michael acceptor. Next, the in vitro chemical stability of curcumin is elaborated in the context of its susceptibility to photochemical and chemical modification and degradation (e.g., alkaline hydrolysis). Specific modification and degradatory pathways are provided, which mainly entail radical-based intermediates, and the in vitro catabolites are identified. The implications of curcumin's (photo)chemical instability are addressed in light of pharmaceutical curcumin preparations, the use of curcumin analogues, and implementation of nanoparticulate drug delivery systems. Furthermore, the pharmacokinetics of curcumin and its most important degradation products are detailed in light of curcumin's poor bioavailability. Particular emphasis is placed on xenobiotic phase I and II metabolism as well as excretion of curcumin in the intestines (first pass), the liver (second pass), and other organs in addition to the pharmacokinetics of curcumin metabolites and their systemic clearance. Lastly, a summary is provided of the clinical pharmacodynamics of curcumin followed by a detailed account of curcumin's direct molecular targets, whereby the phenotypical/biological changes induced in cancer cells upon completion of the curcumin-triggered signaling cascade(s) are addressed in the framework of the hallmarks of cancer. The direct molecular targets include the ErbB family of receptors, protein kinase C, enzymes involved in prostaglandin synthesis, vitamin D receptor, and DNA.

Curcuma Contra Cancer? Curcumin and Hodgkin's Lymphoma

Curcumin, a phytochemical isolated from curcuma plants which are used as coloring ingredient for the preparation of curry powder, has several activities which suggest that it might be an interesting drug for the treatment or prevention of cancer. Curcumin targets different pathways which are involved in the malignant phenotype of tumor cells, including the nuclear factor kappa B (NFKB) pathway. This pathway is deregulated in multiple tumor entities, including Hodgkin’s lymphoma (HL). Indeed, curcumin can inhibit growth of HL cell lines and increases the sensitivity of these cells for cisplatin. In this review we summarize curcumin activities with special focus on possible activities against HL cells.

Curcumin acts as a pro-oxidant inducing apoptosis via JNKs in the isolated perfused Rana ridibunda heart

Amphibians are known to better tolerate and endure adverse environmental conditions such as redox imbalances conferred by reactive oxygen species (ROS), compared to mammals. Interestingly, the exact adaptation strategies and signaling mechanisms mediating these effects have not been fully elucidated. Therefore, in the present study, we probed into the molecular response of the isolated perfused Rana ridibunda heart to curcumin, in the context of mitogen-activated protein kinases (MAPKs) phosphorylation patterns and apoptotic markers occurrence. In particular, this polyphenol was found to exert a pro-oxidant effect in our model and to significantly upregulate p38-MAPK and JNKs phosphorylation (thus activation). The early apoptosis observed, substantiated by poly(ADP-ribose) polymerase (PARP) cleavage, was established to be JNKs- and ROS-mediated, while no involvement of p38-MAPK was detected. Subsequently, the pro-oxidative activity of curcumin was confirmed to mimic H(2) O(2). Furthermore, NADPH oxidase as well as Na(+) /K(+) -ATPase were found to mediate JNKs phosphorylation as well as PARP proteolytic cleavage. Curcumin exerts pleiotropic actions, both beneficial and detrimental and is currently the subject of intense scientific research. Being a low-molecular-weight antioxidant, it is intriguing to investigate curcumin's role in redox homeostasis in the amphibian heart, under conditions that apparently favor its pro-oxidative properties. Comparative studies of its multifaceted role in different species may contribute to the clarification of the signaling mechanisms it triggers and the terminal physiological response it confers. Collectively, this is to our knowledge, the first time that the signal transduction pathways stimulated by curcumin have been assessed in a non-mammalian species.

Effects of flavocoxid, a dual inhibitor of COX and 5-lipoxygenase enzymes, on benign prostatic hyperplasia

BACKGROUND AND PURPOSE

Inflammation plays a key role in the development of benign prostatic hyperplasia (BPH). Eicosanoids derived from the COX and 5-lipoxygenase (5-LOX) pathways are elevated in the enlarging prostate. Flavocoxid is a novel flavonoid-based 'dual inhibitor' of the COX and 5-LOX enzymes. This study evaluated the effects of flavocoxid in experimental BPH.

EXPERIMENTAL APPROACH

Rats were treated daily with testosterone propionate (3 mg·kg(-1)  s.c.) or its vehicle for 14 days to induce BPH. Animals receiving testosterone were randomized to receive vehicle (1 mL·kg(-1) , i.p.) or flavocoxid (20 mg·kg(-1) , i.p.) for 14 days. Histological changes, eicosanoid content and mRNA and protein levels for apoptosis-related proteins and growth factors were assayed in prostate tissue. The effects of flavocoxid were also tested on human prostate carcinoma PC3 cells.

KEY RESULTS

Flavocoxid reduced prostate weight and hyperplasia, blunted inducible expression of COX-2 and 5-LOX as well as the increased production of PGE(2) and leukotriene B(4) (LTB(4) ), enhanced pro-apoptotic Bax and caspase-9 and decreased the anti-apoptotic Bcl-2 mRNA. Flavocoxid also reduced EGF and VEGF expression. In PC3 cells, flavocoxid stimulated apoptosis and inhibited growth factor expression. Flavocoxid-mediated induction of apoptosis was inhibited by the pan-caspase inhibitor, Z-VAD-FMK, in PC3 cells, suggesting an essential role of caspases in flavocoxid-mediated apoptosis during prostatic growth.

CONCLUSION AND IMPLICATIONS

Our results show that a 'dual inhibitor' of the COX and 5-LOX enzymes, such as flavocoxid, might represent a rational approach to reduce BPH through modulation of eicosanoid production and a caspase-induced apoptotic mechanism.

Ceramide-orchestrated signalling in cancer cells

One crucial barrier to progress in the treatment of cancer has been the inability to control the balance between cell proliferation and apoptosis: enter ceramide. Discoveries over the past 15 years have elevated this sphingolipid to the lofty position of a regulator of cell fate. Ceramide, it turns out, is a powerful tumour suppressor, potentiating signalling events that drive apoptosis, autophagic responses and cell cycle arrest. However, defects in ceramide generation and metabolism in cancer cells contribute to tumour cell survival and resistance to chemotherapy. This Review focuses on ceramide signalling and the targeting of specific metabolic junctures to amplify the tumour suppressive activities of ceramide. The potential of ceramide-based therapeutics in the treatment of cancer is also discussed.

Dehydrozingerone, a structural analogue of curcumin, induces cell-cycle arrest at the G2/M phase and accumulates intracellular ROS in HT-29 human colon cancer cells

Dehydrozingerone (1) is a pungent constituent present in the rhizomes of ginger (Zingiber officinale) and belongs structurally to the vanillyl ketone class. It is a representative of half the chemical structure of curcumin (2), which is an antioxidative yellow pigment obtained from the rhizomes of turmeric (Curcuma longa). Numerous studies have suggested that 2 is a promising phytochemical for the inhibition of malignant tumors, including colon cancer. On the other hand, there have been few studies on the potential antineoplastic properties of 1, and its mode of action based on a molecular mechanism is little known. Therefore, the antiproliferative effects of 1 were evaluated against HT-29 human colon cancer cells, and it was found that 1 dose-dependently inhibited growth at the G2/M phase with up-regulation of p21. Dehydrozingerone additionally led to the accumulation of intracellular ROS, although most radical scavengers could not clearly repress the cell-cycle arrest at the G2/M phase. Furthermore, two synthetic isomers of 1 (iso-dehydrozingerone, 3, and ortho-dehydrozingerone, 4) were also examined. On comparing of their activities, accumulation of intracellular ROS was found to be interrelated with growth-inhibitory effects. These results suggest that analogues of 1 may be potential chemotherapeutic agents for colon cancer.

Curcumin and synthetic analogs induce reactive oxygen species and decreases specificity protein (Sp) transcription factors by targeting microRNAs

Background

Curcumin inhibits growth of several cancer cell lines, and studies in this laboratory in bladder and pancreatic cancer cells show that curcumin downregulates specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 and pro-oncogenic Sp-regulated genes. In this study, we investigated the anticancer activity of curcumin and several synthetic cyclohexanone and piperidine analogs in colon cancer cells.

Methods

The effects of curcumin and synthetic analogs on colon cancer cell proliferation and apoptosis were determined using standardized assays. The changes in Sp proteins and Sp-regulated gene products were analysed by western blots, and real time PCR was used to determine microRNA-27a (miR-27a), miR-20a, miR-17-5p and ZBTB10 and ZBTB4 mRNA expression.

Results

The IC₅₀ (half-maximal) values for growth inhibition (24 hr) of colon cancer cells by curcumin and synthetic cyclohexanone and piperidine analogs of curcumin varied from 10 μM for curcumin to 0.7 μM for the most active synthetic piperidine analog RL197, which was used along with curcumin as model agents in this study. Curcumin and RL197 inhibited RKO and SW480 colon cancer cell growth and induced apoptosis, and this was accompanied by downregulation of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 and Sp-regulated genes including the epidermal growth factor receptor (EGFR), hepatocyte growth factor receptor (c-MET), survivin, bcl-2, cyclin D1 and NFκB (p65 and p50). Curcumin and RL197 also induced reactive oxygen species (ROS), and cotreatment with the antioxidant glutathione significantly attenuated curcumin- and RL197-induced growth inhibition and downregulation of Sp1, Sp3, Sp4 and Sp-regulated genes. The mechanism of curcumin-/RL197-induced repression of Sp transcription factors was ROS-dependent and due to induction of the Sp repressors ZBTB10 and ZBTB4 and downregulation of microRNAs (miR)-27a, miR-20a and miR-17-5p that regulate these repressors.

Conclusions

These results identify a new and highly potent curcumin derivative and demonstrate that in cells where curcumin and RL197 induce ROS, an important underlying mechanism of action involves perturbation of miR-ZBTB10/ZBTB4, resulting in the induction of these repressors which downregulate Sp transcription factors and Sp-regulated genes.

Effects of Proliferation and Apoptosis in Human Gastric Cancer Cell Line SGC-7901 Induced by Zedoary Turmeric Oil

Objective To study the effect of Zedoary turmeric oil on proliferation and apoptosis of human gastric cancer cell line SGC-7901. The growth inhibition rate of different concentration of Zedoary turmeric oil on human gastric cancer cell line SGC-7901 were detected by trypan blue stain assay. Optical microscopy observation of cell morphological changes. DNA fragmentation detected by agarose gel electrophoresis. Flow cytometry was used to detect the changes of cell mitochondrial membrane potential, apoptosis rate and cell cycle distribution.Results: the optimal concentration was110 μg/mL for 48h，and the IC50 values were 104.958 μg/mL. The typical DNA ladder on agarose gel electrophoresis，the apoptotic peak was showed by FCA detection. Conclusion: The Zedoary turmeric oil can induce apoptosis of gastric cancer cell SGC-7901.

Premature mitochondrial senescence and related ultrastructural changes during lung carcinogenesis modulation by curcumin and resveratrol

The present study attempted to explore the efficacy of curcumin and resveratrol in modulating premature mitochondria senescence and ultrastructural changes during lung carcinogenesis. The mice were segregated into 5 groups, which included normal control, benzo[a]pyrene (BP) treated, BP + curcumin (C) treated, BP + resveratrol (R) treated, and BP + C + R treated groups. Animals were given a single ip injection of benzo[a]pyrene in corn oil at a dose level of 100 mg/kg body weight. Treatments of curcumin and resveratrol were given orally in drinking water at a dose level of 60 mg/kg body weight and 5.7 µg/mL drinking water, respectively, 3 times a week for a total duration of 22 weeks. Ultrastructure of BP-treated mice revealed disruptions in cellular integrity along with nuclear deformation and premature mitochondrial senescence. Interestingly, supplementation of curcumin and resveratrol individually resulted in improvement of ultrahistoarchitecture of BP-treated mice but the improvement was much greater with combined supplementation of phytochemicals. Further, benzo[a]pyrene treatment revealed alterations in lung histoarchitecture, which, however, was improved appreciably following combined supplementation with curcumin and resveratrol. The present study concludes that combined supplementation with curcumin and resveratrol effectively modulates histoarchitecture as well as ultrahistoarchitecture during benzo[a]pyrene-induced lung carcinogenesis in mice. Cancer is a public health problem worldwide. Lung cancer is a major cause of mortality throughout the world and is responsible for the deaths of more than one million people annually. Phytochemicals have shown great potential in preventing the occurrence of cancer and other chronic diseases that result from oxidative stress induced by free radicals. Phytochemicals are nonnutritive products of plants and, being nontoxic, are presently being studied the world over for their chemopreventive actions in controlling various diseases, including cancer. In the present study, curcumin and resveratrol are the phytochemicals of interest. Curcumin, a polyphenol, has been reported to have anti-invasive properties. Further, curcumin has been shown to activate apoptotic machinery in patients with lung cancer. On the other hand, resveratrol (trans-3,4,5- thihydroxystibene) is a phytoalexin that is present naturally in grapes as well as in a variety of medicinal plants and has been shown to exhibit antioxidant activity with a potential to induce apoptosis.

Effects of curcumin on bleomycin‑induced oxidative stress in malignant testicular germ cell tumors

Bleomycin is commonly used in the treatment of testicular cancer. Bleomycin generates oxygen radicals, induces the oxidative cleavage of DNA strands and induces cancer cell apoptosis. Curcumin (diferuloylmethane) is a potent antioxidant and chief component of the spice turmeric. No study investigating the effects of curcumin on intrinsic and bleomycin-induced oxidative stress in testicular germ cell tumors has been reported in the literature. For this reason, the present study aimed to examine the effects of curcumin on oxidative stress produced in wild-type NTera-2 and p53-mutant NCCIT testicular cancer cells incubated with bleomycin and the results were compared with cells treated with H2O2 which directly produces oxidative stress. The protein carbonyl content, thiobarbituric acid reactive substances (TBARS), glutathione (GSH), 8-isoprostane, lipid hydroperoxide (LPO) levels and total antioxidant capacity in the two testicular cancer cell lines were determined. Results showed that bleomycin and H2O2 significantly increased protein carbonyl, TBARS, 8-isoprostane and LPO levels in the NTera-2 and NCCIT cell lines. Bleomycin and H2O2 significantly decreased the antioxidant capacity and GSH levels in NTera-2 cells. Curcumin significantly decreased LPO, 8-isoprostane and protein carbonyl content, and TBARS levels increased in cells treated with bleomycin and H2O2. Curcumin enhanced GSH levels and the antioxidant capacity of NTera-2 cells. In conclusion, curcumin inhibits bleomycin and H2O2-induced oxidative stress in human testicular cancer cells.

Sphingosine kinase-1 inhibition sensitizes curcumin-induced growth inhibition and apoptosis in ovarian cancer cells

Recent published studies suggest that increasing levels of ceramides enhance the chemo-sensitivity of curcumin. Using in vitro approaches, we analyzed the impact of sphingosine kinase-1 (SphK-1) inhibition on ceramide production, and evaluated SphK1 inhibitor II (SKI-II) as a potential curcumin chemo-sensitizer in ovarian cancer cells. We found that SphK1 is overexpressed in ovarian cancer patients' tumor tissues and in cultured ovarian cancer cell lines. Inhibition of SphK1 by SKI-II or by RNA interference (RNAi) knockdown dramatically enhanced curcumin-induced apoptosis and growth inhibition in ovarian cancer cells. SKI-II facilitated curcumin-induced ceramide production, p38 activation and Akt inhibition. Inhibition of p38 by the pharmacological inhibitor (SB 203580), a dominant-negative expression vector, or by RNAi diminished curcumin and SKI-II co-administration-induced ovarian cancer cell apoptosis. In addition, restoring Akt activation introducing a constitutively active Akt, or inhibiting ceramide production by fumonisin B1 also inhibited the curcumin plus SKI-II co-administration-induced in vitro anti-ovarian cancer effect, suggesting that ceramide accumulation, p38 activation and Akt inhibition are downstream effectors. Our findings suggest that low, well-tolerated doses of SKI-II may offer significant improvement to the clinical curcumin treatment of ovarian cancer.

Enhanced apoptotic effects by the combination of curcumin and methylseleninic acid: potential role of Mcl-1 and FAK

Curcumin and methylseleninic acid (MSeA) are well-documented dietary chemopreventive agents. Apoptosis appears to be a major mechanism for both agents to exert anti-cancer activity. The purpose of the present study was designed to determine whether the apoptotic effect on human cancer cells can be enhanced by combining curcumin with MSeA. Apoptosis was evaluated by Annexin V staining of externalized phosphatidylserine by flow cytometry. Expression of protein was analyzed by Western blotting. Localization of apoptosis-inducing factor (AIF) was detected by immunocytochemistry. RNA interference was employed to inhibit expression of specific protein. We found here that combining curcumin with MSeA led to a significantly enhanced apoptosis in both MDA-MB-231 breast cancer cells and DU145 prostate cancer cells. Further mechanistic investigations revealed that curcumin treatment alone caused a concentration dependent upregulation of Mcl-1, which can be overcome by combining it with MSeA. In line with the Mcl-1 reduction, an enhanced mitochondrial permeability transition and AIF nuclear translocation by the combination were achieved. In addition, an increased suppression of focal adhesion kinase activity was observed in the combination-treated cells which were associated with cell detachment-induced apoptosis by the combination. Our findings suggest that curcumin/MSeA combination holds excellent potential for improving their efficacy against human breast and prostate cancer through enhanced apoptosis induction.