Curcumin enhances TRAIL-induced apoptosis of breast cancer cells by regulating apoptosis-related proteins

Licochalcone D exhibits cytotoxicity in breast cancer cells and enhances tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis through upregulation of death receptor 5

Anticancer strategies using natural products or derivatives are promising alternatives for cancer treatment. Here, we showed that licochalcone D (LCD), a natural flavonoid extracted from Glycyrrhiza uralensis Fisch, suppressed the growth of breast cancer cells, and was less toxic to MCF-10A normal breast cells. LCD-induced DNA damage, cell cycle arrest, and apoptosis in breast cancer cells. Furthermore, LCD potentiated tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced cytotoxicity. Mechanistically, LCD was revealed to reduce survival protein expression and to upregulate death receptor 5 (DR5) expressions. Silencing DR5 blocked the ability of LCD to sensitize cells to TRAIL-mediated apoptosis. LCD increased CCAAT/enhancer-binding protein homologous protein (CHOP) expression in breast cancer cells. Knockdown of CHOP attenuated DR5 upregulation and apoptosis triggered by cotreatment with LCD and TRAIL. Furthermore, LCD suppressed the phosphorylation of extracellular signal-regulated kinase and promoted the phosphorylation of c-Jun amino-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). Pretreatment with JNK inhibitor SP600125 or p38 MAPK inhibitor SB203580 abolished the upregulation of DR5 and CHOP, and also attenuated LCD plus TRAIL-induced cleavage of poly(ADP-ribose) polymerase. Overall, our results show that LCD exerts cytotoxic effects on breast cancer cells and arguments TRAIL-mediated apoptosis by inhibiting survival protein expression and upregulating DR5 in a JNK/p38 MAPK-CHOP-dependent manner.

Combination of Etoposide and quercetin-loaded solid lipid nanoparticles Potentiates apoptotic effects on MDA-MB-231 breast cancer cells

Background

Breast cancer is a major global cancer, for which radiation and chemotherapy are the main treatments. Natural remedies are being studied to reduce the side effects. Etoposide (ETO), a chemo-drug, and quercetin (QC), a phytochemical, are considered potential factors for adaptation to conventional treatments.

Objectives

The anticancer effect of the synergy between ETO and Quercetin-loaded solid lipid nanoparticles (QC-SLNs), was investigated in MDA-MB-231 cells.

Methods

We developed QC-SLNs for efficient cellular delivery, characterizing their morphology, particle size, and zeta potential. We assessed the cytotoxicity of QC-SLNs and ETO on breast cancer cells via the MTT assay. Effects on apoptosis intensity in MDA-MB-231 cells have been detected utilizing annexin V-FITC, PI, and caspase activities. Real-time PCR assessed Bax gene and Bcl-2 gene fold change expression, while Western blot analysis determined p53 and p21 protein levels.

Results

Spherical, negatively charged QC-SLNs, when combined with ETO, significantly enhanced inhibition of MDA-MB-231 cell proliferation compared to ETO or QC-SLNs alone. The combined treatment also notably increased the apoptosis pathway. QC-SLNs + ETO increased the Bax/Bcl-2 gene ratio, elevated p53 and p21 proteins, and activated caspase 3 and 9 enzymes. These results indicate the potential for QC-SLNs + ETO as a strategy for breast cancer treatment, potentially overcoming ETO-resistant breast cancer chemoresistance.

Conclusion

These results suggest that QC-SLN has the potential to have a substantial impact on the breast cancer cure by improving the efficacy of ETO. This enhancement could potentially help overcome chemoresistance observed in ETO-resistant breast cancer.

Spatial distribution of tumor-associated macrophages in an orthotopic prostate cancer mouse model

Mounting evidence suggests that the immune landscape within prostate tumors influences progression, metastasis, treatment response, and patient outcomes. In this study, we investigated the spatial density of innate immune cell populations within NOD.SCID orthotopic prostate cancer xenografts following microinjection of human DU145 prostate cancer cells. Our laboratory has previously developed nanoscale liposomes that attach to leukocytes via conjugated E-selectin (ES) and kill cancer cells via TNF-related apoptosis inducing ligand (TRAIL). Immunohistochemistry (IHC) staining was performed on tumor samples to identify and quantify leukocyte infiltration for different periods of tumor growth and E-selectin/TRAIL (EST) liposome treatments. We examined the spatial-temporal dynamics of three different immune cell types infiltrating tumors using QuPath image analysis software. IHC staining revealed that F4/80+ tumor-associated macrophages (TAMs) were the most abundant immune cells in all groups, irrespective of time or treatment. The density of TAMs decreased over the course of tumor growth and decreased in response to EST liposome treatments. Intratumoral versus marginal analysis showed a greater presence of TAMs in the marginal regions at 3 weeks of tumor growth which became more evenly distributed over time and in tumors treated with EST liposomes. TUNEL staining indicated that EST liposomes significantly increased cell apoptosis in treated tumors. Additionally, confocal microscopy identified liposome-coated TAMs in both the core and periphery of tumors, highlighting the ability of liposomes to infiltrate tumors by "piggybacking" on macrophages. The results of this study indicate that TAMs represent the majority of innate immune cells within NOD.SCID orthotopic prostate tumors, and spatial density varies widely as a function of tumor size, duration of tumor growth, and treatment of EST liposomes.

Evodiamine Exhibits Anti-Bladder Cancer Activity by Suppression of Glutathione Peroxidase 4 and Induction of Ferroptosis

Evodiamine (EVO) exhibits anti-cancer activity through the inhibition of cell proliferation; however, little is known about its underlying mechanism. To determine whether ferroptosis is involved in the therapeutic effects of EVO, we investigated critical factors, such as lipid peroxidation levels and glutathione peroxidase 4 (GPX4) expression, under EVO treatment. Our results showed that EVO inhibited the cell proliferation of poorly differentiated, high-grade bladder cancer TCCSUP cells in a dose- and time-dependent manner. Lipid peroxides were detected by fluorescence microscopy after cancer cell exposure to EVO. GPX4, which catalyzes the conversion of lipid peroxides to prevent cells from undergoing ferroptosis, was decreased dose-dependently by EVO treatment. Given the features of iron dependency and lipid-peroxidation-driven death in ferroptosis, the iron chelator deferoxamine (DFO) was used to suppress EVO-induced ferroptosis. The lipid peroxide level significantly decreased when cells were treated with DFO prior to EVO treatment. DFO also attenuated EVO-induced cell death. Co-treatment with a pan-caspase inhibitor or necroptosis inhibitor with EVO did not alleviate cancer cell death. These results indicate that EVO induces ferroptosis rather than apoptosis or necroptosis. Furthermore, EVO suppressed the migratory ability, decreased the expression of mesenchymal markers, and increased epithelial marker expression, determined by a transwell migration assay and Western blotting. The TCCSUP bladder tumor xenograft tumor model confirmed the effects of EVO on the inhibition of tumor growth and EMT. In conclusion, EVO is a novel inducer for activating the ferroptosis of bladder cancer cells and may be a potential therapeutic agent for bladder cancer.

Therapeutic Effects of Coumarins with Different Substitution Patterns

The use of derivatives of natural and synthetic origin has gained attention because of their therapeutic effects against human diseases. Coumarins are one of the most common organic molecules and are used in medicine for their pharmacological and biological effects, such as anti-inflammatory, anticoagulant, antihypertensive, anticonvulsant, antioxidant, antimicrobial, and neuroprotective, among others. In addition, coumarin derivates can modulate signaling pathways that impact several cell processes. The objective of this review is to provide a narrative overview of the use of coumarin-derived compounds as potential therapeutic agents, as it has been shown that substituents on the basic core of coumarin have therapeutic effects against several human diseases and types of cancer, including breast, lung, colorectal, liver, and kidney cancer. In published studies, molecular docking has represented a powerful tool to evaluate and explain how these compounds selectively bind to proteins involved in various cellular processes, leading to specific interactions with a beneficial impact on human health. We also included studies that evaluated molecular interactions to identify potential biological targets with beneficial effects against human diseases.

Coriolus versicolor and its bioactive molecule are potential immunomodulators against cancer cell metastasis via inactivation of MAPK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Coriolus versicolor (CV) has been used in traditional Chinese medicine for over 2000 years as a premium medicine for enhancing good health and longevity. The immunomodulatory and anti-cancer effects of polysaccharopeptides (PSP) from cultured CV have been extensively studied; however, the effect and the mechanism of action of other small molecules from CV remain unknown.

AIM OF THE STUDY

we aim to examine the immunomodulatory and anti-cancer effects of the small molecules from CV (SMCV) and identify the active compounds that are responsible for the biological effects against glioblastoma multiforme cells.

MATERIALS AND METHODS

The effects of SMCV/active compound on cytokine and MMP mRNA expressions and productions were assessed by quantitative reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. An active compound from SMCV was identified with a bioassay-guided fractionation scheme. The potential mode of action of the active compound was further investigated by identifying the cell signaling pathway. The protein expressions of phospho-ERK, phospho-JNK and phospho-p38 MAPKs were measured by Western Blotting. The anti-invasive effect of SMCV/bioactive compound against T98G, lung carcinoma (A549), and breast adenocarcinoma (MDA-MB-231) cells were determined using invasion assay.

RESULTS

Our results showed that SMCV had strong immunomodulatory effect by suppressing LPS-induced TNF-α production, whereas increasing poly I:C-induced IFN-β level in PBMac. SMCV not only possessed indirect anti-cancer effect by suppressing TNF-α-induced MMP-3 production in glioblastoma T98G cells, but also directly reduced the invasion ability of malignant cells including T98G, A549 and MDA-MB-231. Using bioassay-guided fractionation scheme, we isolated 9-KODE methyl ester (compound AM) that was responsible for the bioactivity of SMCV. This compound suppressed TNF-α-induced MMP-3 production in T98G cells and the suppression may be correlated with the inactivation of p38 mitogen-activated protein kinase (MAPK) pathway. Moreover, compound AM also directly reduced T98G cell invasion.

CONCLUSION

Results of our present study provides scientific evidence that SMCV possesses immunomodulatory and anti-cancer effects. Its bioactive compound, compound AM, is a potential new drug candidate against the invasion and metastasis of glioblastoma cells.

The Involvement of Natural Polyphenols in Molecular Mechanisms Inducing Apoptosis in Tumor Cells: A Promising Adjuvant in Cancer Therapy

Various literature data show how a diet rich in vegetables could reduce the incidence of several cancers due to the contribution of the natural polyphenols contained in them. Polyphenols are attributed multiple pharmacological actions such as anti-inflammatory, anti-oxidant, antibiotic, antiseptic, anti-allergic, cardioprotective and even anti-tumor properties. The multiple mechanisms involved in their anti-tumor action include signaling pathways modulation associated with cell proliferation, differentiation, migration, angiogenesis, metastasis and cell death. Since the dysregulation of death processes is involved in cancer etiopathology, the natural compounds able to kill cancer cells could be used as new anticancer agents. Apoptosis, a programmed form of cell death, is the most potent defense against cancer and the main mechanism used by both chemotherapy agents and polyphenols. The aim of this review is to provide an update of literature data on the apoptotic molecular mechanisms induced by some representative polyphenol family members in cancer cells. This aspect is particularly important because it may be useful in the design of new therapeutic strategies against cancer involving the polyphenols as adjuvants.

Synergistic correlation between host angiogenin and dengue virus replication

DENV infection poses a major health concern globally and the pathophysiology relies heavily on host-cellular machinery. Although virus replication relies heavily on the host, the mechanistic details of DENV-host interaction is not fully characterized yet. Here, we are focusing on characterizing the mechanistic basis of virus-induced stress on the host cell. Specifically, we aim to characterize the role of the stress modulator ribonuclease Angiogenin during DENV infection. Our results suggested that the levels of Angiogenin are up-regulated in DENV-infected cells and the levels increase proportionately with DENV replication. Our efforts to knockdown Angiogenin using siRNA were unsuccessful in DENV-infected cells but not in mock-infected control. To further investigate the modulation between DENV replication and Angiogenin, we treated Huh7 cells with Ivermectin prior to DENV infection. Our results suggest a significant reduction in DENV replication specifically at the later stages as a consequence of Ivermectin treatment. Interestingly, Angiogenin levels were also found to be decreased proportionately. Our results suggest that Angiogenin modulation during DENV infection is important for DENV replication and pathogenesis.

New Visions on Natural Products and Cancer Therapy: Autophagy and Related Regulatory Pathways

Macroautophagy (autophagy) has been a highly conserved process throughout evolution and allows cells to degrade aggregated/misfolded proteins, dysfunctional or superfluous organelles and damaged macromolecules, in order to recycle them for biosynthetic and/or energetic purposes to preserve cellular homeostasis and health. Changes in autophagy are indeed correlated with several pathological disorders such as neurodegenerative and cardiovascular diseases, infections, cancer and inflammatory diseases. Conversely, autophagy controls both apoptosis and the unfolded protein response (UPR) in the cells. Therefore, any changes in the autophagy pathway will affect both the UPR and apoptosis. Recent evidence has shown that several natural products can modulate (induce or inhibit) the autophagy pathway. Natural products may target different regulatory components of the autophagy pathway, including specific kinases or phosphatases. In this review, we evaluated ~100 natural compounds and plant species and their impact on different types of cancers via the autophagy pathway. We also discuss the impact of these compounds on the UPR and apoptosis via the autophagy pathway. A multitude of preclinical findings have shown the function of botanicals in regulating cell autophagy and its potential impact on cancer therapy; however, the number of related clinical trials to date remains low. In this regard, further pre-clinical and clinical studies are warranted to better clarify the utility of natural compounds and their modulatory effects on autophagy, as fine-tuning of autophagy could be translated into therapeutic applications for several cancers.

Curcumin Sensitises Cancerous Kidney Cells to TRAIL Induced Apoptosis via Let-7C Mediated Deregulation of Cell Cycle Proteins and Cellular Metabolism

Targeted therapies are the most attractive options in the treatment of different tumours, including kidney cancers. Such therapies have entered a golden era due to advancements in research, breakthroughs in scientific knowledge, and a better understanding of cancer therapy mechanisms, which significantly improve the survival rates and life expectancy of patients. The use of tumour necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) as an anticancer therapy has attracted the attention of the scientific community and created great excitement due to its selectivity in targeting cancerous cells with no toxic impacts on normal tissues. However, clinical studies disappointingly showed the emergence of resistance against TRAIL. This study aimed to employ curcumin to sensitise TRAIL-resistant kidney cancerous ACHN cells, as well as to gain insight into the molecular mechanisms of TRAIL sensitization. Curcumin deregulated the expression of apoptosis-regulating micro Ribonucleic Acid (miRNAs), most notably, let-7C. Transfecting ACHN cells with a let-7C antagomir significantly increased the expression of several cell cycle protein, namely beta (β)-catenin, cyclin dependent kinase (CDK)1/2/4/6 and cyclin B/D. Further, it overexpressed the expression of the two key glycolysis regulating proteins including hypoxia-inducible factor 1-alpha (HIF-1α) and pyruvate dehydrogenase kinase 1 (PDK1). Curcumin also suppressed the expression of the overexpressed proteins when added to the antagomir transfected cells. Overall, curcumin targeted ACHN cell cycle and cellular metabolism by promoting the differential expression of let-7C. To the best of our knowledge, this is the first study to mechanistically report the cancer chemosensitisation potential of curcumin in kidney cancer cells via induction of let-7C.

Curcumin: Modulator of Key Molecular Signaling Pathways in Hormone-Independent Breast Cancer

Simple Summary

Breast cancer remains the most commonly diagnosed cancer and the leading cause of cancer death among females worldwide. It is a highly heterogeneous disease, classified according to hormone and growth factor receptor expression. Patients with triple negative breast cancer (TNBC) (estrogen receptor-negative/progesterone receptor-negative/human epidermal growth factor receptor (HER2)-negative) and hormone-independent HER2 overexpressing subtypes still represent highly aggressive behavior, metastasis, poor prognosis, and drug resistance. Thus, new alternative anticancer agents based on the use of natural products have been receiving enormous attention. In this regard, curcumin is a promising lead in cancer drug discovery due its ability to modulate a diverse range of molecular targets and signaling pathways. The current review has emphasized the underlying mechanism of curcumin anticancer action mediated through the modulation of PI3K/Akt/mTOR, JAK/STAT, MAPK, NF-ĸB, p53, Wnt/β-catenin, apoptosis, and cell cycle pathways in hormone-independent breast cancer, providing frameworks for future studies and insights to improve its efficiency in clinical practice.

Abstract

Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death among women worldwide. Despite the overall successes in breast cancer therapy, hormone-independent HER2 negative breast cancer, also known as triple negative breast cancer (TNBC), lacking estrogens and progesterone receptors and with an excessive expression of human epidermal growth factor receptor 2 (HER2), along with the hormone-independent HER2 positive subtype, still remain major challenges in breast cancer treatment. Due to their poor prognoses, aggressive phenotype, and highly metastasis features, new alternative therapies have become an urgent clinical need. One of the most noteworthy phytochemicals, curcumin, has attracted enormous attention as a promising drug candidate in breast cancer prevention and treatment due to its multi-targeting effect. Curcumin interrupts major stages of tumorigenesis including cell proliferation, survival, angiogenesis, and metastasis in hormone-independent breast cancer through the modulation of multiple signaling pathways. The current review has highlighted the anticancer activity of curcumin in hormone-independent breast cancer via focusing on its impact on key signaling pathways including the PI3K/Akt/mTOR pathway, JAK/STAT pathway, MAPK pathway, NF-ĸB pathway, p53 pathway, and Wnt/β-catenin, as well as apoptotic and cell cycle pathways. Besides, its therapeutic implications in clinical trials are here presented.

The Novel Curcumin Derivative 1g Induces Mitochondrial and ER-Stress-Dependent Apoptosis in Colon Cancer Cells by Induction of ROS Production

Reactive oxygen species (ROS) play an important role in cellular metabolism. Many chemotherapeutic drugs are known to promote apoptosis through the production of ROS. In the present study, the novel curcumin derivative, 1g, was found to inhibit tumor growth in colon cancer cells both in vitro and in vivo. Bioinformatics was used to analyze the differentially expressed mRNAs. The mechanism of this effect was a change in mitochondrial membrane potential caused by 1g that increased its pro-apoptotic activity. In addition, 1g produced ROS, induced G1 checkpoint blockade, and enhanced endoplasmic reticulum (ER)-stress in colon cancer cells. Conversely, pretreatment with the ROS scavenging agent N-acetyl-l-cysteine (NAC) inhibited the mitochondrial dysfunction caused by 1g and reversed ER-stress, cell cycle stagnation, and apoptosis. Additionally, pretreatment with the p-PERK inhibitor GSK2606414 significantly reduced ER-stress and reversed the apoptosis induced by colon cancer cells. In summary, the production of ROS plays an important role in the destruction of colon cancer cells by 1g and demonstrates that targeted strategies based on ROS represent a promising approach to inhibit colon cancer proliferation. These findings reveal that the novel curcumin derivative 1g represents a potential candidate therapeutics for the treatment of colon cancer cells, via apoptosis caused by mitochondrial dysfunction and endoplasmic reticulum stress.

Tanshinone IIA sensitizes TRAIL-induced apoptosis in glioblastoma through inducing the expression of death receptors (and suppressing STAT3 activation)

OBJECTIVE

This work was designed to explore whether the combination of Tanshinone IIA (T-IIA) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has a direct anti-cancer effect in glioblastoma (GBM) and the possible mechanisms.

METHODS

GBM cells (U-87 and U-251 MG) were treated with T-IIA or/and TRAIL, or the expression of death receptors (DRs), DR4 and DR5, was suppressed in GBM cells. The activity of GBM cells was determined by MTT, and the apoptosis was assessed by Hoechst33342 staining and flow cytometry. The expression levels of cleaved caspase-3/8/9, phosphorylated (p)-STAT3 as well as DR4 and DR5 in GBM cells were assessed by Western blotting. A nude mouse xenograft model was constructed to evaluate the effects of T-IIA and TRAIL cotreatment on tumor growth and apoptosis in vivo.

RESULTS

After T-IIA treatment, GBM cells resumed the sensitivity to TRAIL-induced apoptosis dependent on inhibition of p-STAT3 and activation of DR4, DR5 and caspases. DR4 or/and DR5 knockdown significantly abated the co-effect of T-IIA and TRAIL on GBM cell apoptosis and proliferation. Furthermore, T-IIA and TRAIL cotreatment markedly inhibited the growth of transplanted tumor and activated U87 cell apoptosis in nude mice.

CONCLUSION

T-IIA increases TRAIL-induced apoptosis by downregulating STAT3 and upregulating DR4 and DR5, indicating T-IIA therapy as a novel treatment strategy for TRAIL-resistant GBM.

Thymoquinone sensitizes human hepatocarcinoma cells to TRAIL-induced apoptosis via oxidative DNA damage

INTRODUCTION

Hepatocellular carcinoma (HCC) remains one of the most predominant types of digestive system malignancies worldwide. TNF-related apoptosis-inducing ligand (TRAIL) is a biological cytokine with the mentioned specificity, but some tumor cells' resistance limits its use as a therapeutic approach. The present study aimed to investigate thymoquinone (TQ) and TRAIL's combined effect and the potential mechanisms in human hepatic HepG2 carcinoma cells.

METHODS

Cell viability and IC₅₀ dose for TQ and TRAIL, alone and in combination, were determined using the MTT method. ELISA evaluated the expression levels of 8-Hydroxy-2'-deoxyguanosine. The apoptosis rate was assessed by flow cytometry, ELISA cell death assay, and caspase 8 activity assays. The mRNA and protein evaluation of candidate genes, including survivin, Bcl-2, XIAP, c-IAP1, c-IAP2, and c-FLIP, were accomplished before and after the treatment using qRT-PCR and Western blot analysis, respectively.

RESULTS

Our results showed that TQ synergistically increased TRAIL's cell toxic effects as follows: TQ plus TRAIL > TRAIL > TQ. TQ could sensitize the HepG2 cells against the TRAIL-induced apoptosis and amplify the caspase 8 activity. This outcome is achieved by decreasing the mRNA and protein expression levels of anti-apoptotic genes.

CONCLUSIONS

Our findings suggest that TQ can sensitize the human HCC cell line HepG2 against TRAIL by inducing the death receptor pathway. Moreover, these agents' combinational therapy might promise a therapeutic regimen for improving the clinical efficacy of TRAIL-induced apoptosis in patients with HCC.

Traditional Chinese medicines and their active ingredients sensitize cancer cells to TRAIL-induced apoptosis

The rapidly developing resistance of cancers to chemotherapy agents and the severe cytotoxicity of such agents to normal cells are major stumbling blocks in current cancer treatments. Most current chemotherapy agents have significant cytotoxicity, which leads to devastating adverse effects and results in a substandard quality of life, including increased daily morbidity and premature mortality. The death receptor of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can sidestep p53-dependent pathways to induce tumor cell apoptosis without damaging most normal cells. However, various cancer cells can develop resistance to TRAIL-induced apoptosis via different pathways. Therefore, it is critical to find an efficient TRAIL sensitizer to reverse the resistance of tumor cells to TRAIL, and to reinforce TRAIL's ability to induce tumor cell apoptosis. In recent years, traditional Chinese medicines and their active ingredients have shown great potential to trigger apoptotic cell death in TRAIL-resistant cancer cell lines. This review aims to collate information about Chinese medicines that can effectively reverse the resistance of tumor cells to TRAIL and enhance TRAIL's ability to induce apoptosis. We explore the therapeutic potential of TRAIL and provide new ideas for the development of TRAIL therapy and the generation of new anti-cancer drugs for human cancer treatment. This study involved an extensive review of studies obtained from literature searches of electronic databases such as Google Scholar and PubMed. "TRAIL sensitize" and "Chinese medicine" were the search keywords. We then isolated newly published studies on the mechanisms of TRAIL-induced apoptosis. The name of each plant was validated using certified databases such as The Plant List. This study indicates that TRAIL can be combined with different Chinese medicine components through intrinsic or extrinsic pathways to promote cancer cell apoptosis. It also demonstrates that the active ingredients of traditional Chinese medicines enhance the sensitivity of cancer cells to TRAIL-mediated apoptosis. This provides useful information regarding traditional Chinese medicine treatment, the development of TRAIL-based therapies, and the treatment of cancer.

Curcumin Encapsulated Lecithin Nanoemulsions: An Oral Platform for Ultrasound Mediated Spatiotemporal Delivery of Curcumin to the Tumor

Systemic toxicity caused by conventional chemotherapy is often regarded as one of the major challenges in the treatment of cancer. Over years, the trigger-based modality has gained much attention as it holds the spatiotemporal control over release and internalization of the drug. In this article, we are reporting an increase in the anti-tumor efficacy of curcumin due to ultrasound pulses. MDA MB 231 breast cancer and B16F10 melanoma cells were incubated with lecithin-based curcumin encapsulated nanoemulsions and exposed to ultrasound in the presence and absence of microbubble. Ultrasound induced sonoporation enhanced the cytotoxicity of curcumin in MDA MB 231 and B16F10 cancer cells in the presence of microbubble by 100- and 64-fold, respectively. To study the spatiotemporal delivery of curcumin, we developed B16F10 melanoma subcutaneous tumor on both the flanks of C57BL/6 mice but only the right tumor was exposed to ultrasound. Insonation of the right tumor spatially enhanced the cytotoxicity and enabled the substantial regression of the right tumor compared to the unexposed left tumor which grew continuously in size. This study showed that the ultrasound has the potential to target and increase the drug’s throughput to the tumor and enable effective treatment.

Epigallocatechin-3-Gallate Induces Apoptosis as a TRAIL Sensitizer via Activation of Caspase 8 and Death Receptor 5 in Human Colon Cancer Cells

Though epigallocatechin-3-gallate (EGCG), a major compound of green tea, has anti-diabetes, anti-obesity, anti-inflammatory, and antitumor effects, the underlying antitumor molecular mechanism of EGCG was not fully understood so far. Here the sensitizing effect of EGCG to tumor-necrosis-factor-related apoptosis-inducing ligand (TRAIL) was examined in colorectal cancers. Cotreatment of EGCG and TRAIL synergistically enhanced cytotoxicity and sub G1 accumulation, increased the number of terminal deoxynucleotidyl transferase-dT-mediated dUTP nick end labelling (TUNEL)-positive cells in SW480 and HCT116 cells. Furthermore, this cotreatment promoted the cleavages of poly (adenosine diphosphate-ribose) polymerase (PARP) and induced caspase 8 activation compared to TRAIL or EGCG alone in SW480 and HCT116 cells. Of note, cotreatment of EGCG and TRAIL increased the expression of death receptor 5 (DR5) at protein and mRNA levels and also DR5 cell surface level in colon cancer cells. Conversely, depletion of DR5 reduced the apoptotic activity of cotreatment of EGCG and TRAIL to increase cytotoxicity, sub-G1 population and PARP cleavages in colon cancer cells. Overall, our findings provide evidence that EGCG can be a sensitizer of TRAIL via DR5 and caspase 8 mediated apoptosis in colorectal cancer cells.

Curcumin augments therapeutic efficacy of TRAIL-based immunotoxins in leukemia

BACKGROUND

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) has been perceived as a promising anti-cancer agent because of its unique ability to kill cancer cells while sparing normal cells. However, translation of TRAIL to clinical studies was less successful as a large number of cancer cells acquire resistance to TRAIL-based monotherapies. An ideal strategy to overcome TRAIL resistance is to combine it with potential sensitizing agents.

OBJECTIVE

To investigate the TRAIL-sensitizing effect of curcumin in leukemia.

METHODS

The mechanism underlying TRAIL sensitization by curcumin was studied by flow cytometric analysis of TRAIL receptors in leukemic cell lines and patient samples, and immunoblot detection of TRAIL-apoptosis signaling proteins.

RESULTS

Curcumin augments TRAIL-apoptotic signaling in leukemic cells by upregulating the expression of DR4 and DR5 along with suppression of cFLIP and anti-apoptotic proteins Mcl-1, Bcl-xl, and XIAP. Curcumin pre-treatment significantly (p < 0.01) enhanced the sensitivity of leukemic cell lines to TRAIL recombinant proteins. IL2-TRAIL peptide in the presence of curcumin induced potent apoptosis (p < 0.001) as compared to TRAIL and IL2-TRAIL protein in leukemic cell lines with IC50 < 0.1 μΜ. Additionally, the combination of IL2-TRAIL peptide and curcumin showed significant cytotoxicity in patient peripheral blood mononuclear cells (PBMCs) with an efficacy of 90% in acute myeloid leukemia (AML), but 100% in acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL) and chronic myelomonocytic leukemia (CMML).

CONCLUSION

Overall, our results suggest that curcumin potentiates TRAIL-induced apoptosis through modulation of death receptors and anti-apoptotic proteins which significantly enhances the therapeutic efficacy.

Curcumin Sensitizes Cancers Towards TRAIL-induced Apoptosis via Extrinsic and Intrinsic Apoptotic Pathways

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a natural protein expressed in a wide range of tissues in our body. It is a promising anti-cancer agent due to its selective killing of cancer cells, rendering normal cells unharmed. However, resistance occurs either intrinsically or develops over the course of TRAIL treatment. In view of its specificity to cancer cells, there is a pushing need to overcome TRAIL resistance. Curcumin (Cur), a natural active constituent of turmeric, has been evidenced to have anti-cancer properties. However, it is limited by its sparing solubility and low bioavailability. Combinational therapy is one of the most frequently used strategies to overcome these limitations, which has been proved to be more effective than monotherapy by achieving synergistic effects and reducing toxicity. This review aims to discuss TRAIL and its underlying apoptotic mechanisms, the combinational treatment of Cur and TRAIL in view of their respective limitations, and the underlying apoptotic mechanisms activated by the sensitization of cancers by Cur towards TRAIL-induced apoptosis. Finally, this review discusses the research gap and the author's insight into this research area in bridging the research gap from bench to bedside.

Caudatin potentiates the anti-tumor effects of TRAIL against human breast cancer by upregulating DR5

BACKGROUND

The ability of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to preferentially induce apoptosis in transformed cells while sparing most normal cells is well established. However, the intrinsic and acquired resistance of tumors to TRAIL-induced apoptosis limits its therapeutic applicability.

PURPOSE

We investigated the effect of caudatin, a species of C-21 steroidal glycosides isolated from the roots of Cynanchum auriculatum, on TRAIL-induced apoptosis in human breast cancer cells.

METHODS

Cell growth inhibition was evaluated by the CCK-8 assay. The cell cycle distribution was assessed by propidium iodide flow cytometry. Apoptosis was determined by TUNEL staining. Protein expression was detected by western blotting analysis.

RESULTS

Caudatin enhanced TRAIL-induced apoptosis in human breast cancer cells. This sensitization was achieved by upregulating death receptor 5 (DR5). Knockdown of DR5 abolished the enhancing effect of caudatin on TRAIL responses. The caudatin-induced upregulation of DR5 was accompanied by increased expression of CHOP and phosphorylation of p38 MAPK and JNK. CHOP knockdown blocked caudatin-upregulated DR5 expression. Moreover, cotreatment of breast cancer cells with p38 MAPK and JNK inhibitors significantly counteracted the caudatin-induced expression of DR5.

CONCLUSION

Our results showed that caudatin sensitized breast cancer cells to TRAIL-induced apoptosis through activation of CHOP, p38 MAPK and JNK-mediated upregulation of DR5 expression. The combination of TRAIL and caudatin may be a promising therapeutic approach for the treatment of breast cancer.

Radiosensitizing effect of curcumin-loaded lipid nanoparticles in breast cancer cells

In breast cancer (BC) care, radiotherapy is considered an efficient treatment, prescribed both for controlling localized tumors or as a therapeutic option in case of inoperable, incompletely resected or recurrent tumors. However, approximately 90% of BC-related deaths are due to the metastatic tumor progression. Then, it is strongly desirable to improve tumor radiosensitivity using molecules with synergistic action. The main aim of this study is to develop curcumin-loaded solid nanoparticles (Cur-SLN) in order to increase curcumin bioavailability and to evaluate their radiosensitizing ability in comparison to free curcumin (free-Cur), by using an in vitro approach on BC cell lines. In addition, transcriptomic and metabolomic profiles, induced by Cur-SLN treatments, highlighted networks involved in this radiosensitization ability. The non tumorigenic MCF10A and the tumorigenic MCF7 and MDA-MB-231 BC cell lines were used. Curcumin-loaded solid nanoparticles were prepared using ethanolic precipitation and the loading capacity was evaluated by UV spectrophotometer analysis. Cell survival after treatments was evaluated by clonogenic assay. Dose–response curves were generated testing three concentrations of free-Cur and Cur-SLN in combination with increasing doses of IR (2–9 Gy). IC₅₀ value and Dose Modifying Factor (DMF) was measured to quantify the sensitivity to curcumin and to combined treatments. A multi-“omic” approach was used to explain the Cur-SLN radiosensitizer effect by microarray and metobolomic analysis. We have shown the efficacy of the Cur-SLN formulation as radiosensitizer on three BC cell lines. The DMFs values, calculated at the isoeffect of SF = 50%, showed that the Luminal A MCF7 resulted sensitive to the combined treatments using increasing concentration of vehicled curcumin Cur-SLN (DMF: 1,78 with 10 µM Cur-SLN.) Instead, triple negative MDA-MB-231 cells were more sensitive to free-Cur, although these cells also receive a radiosensitization effect by combination with Cur-SLN (DMF: 1.38 with 10 µM Cur-SLN). The Cur-SLN radiosensitizing function, evaluated by transcriptomic and metabolomic approach, revealed anti-oxidant and anti-tumor effects. Curcumin loaded- SLN can be suggested in future preclinical and clinical studies to test its concomitant use during radiotherapy treatments with the double implications of being a radiosensitizing molecule against cancer cells, with a protective role against IR side effects.

Apoptotic Resistance of Metastatic Tumor Cells in Triple Negative Breast Cancer: Roles of Death Receptor-5

Background: Metastasis is a major cause of death from cancer in triple-negative breast cancer (TNBC). Apoptosis evasion is a critical feature of metastatic tumor cells. Chemopreventive and apoptotic potential of curcumin has been shown in breast cancer. However, the precise mechanism of these effects against metastatic tumor cells has not been clearly addressed yet. Methods: 4T1 cell line was used for induction of metastatic animal model of breast cancer. Primary and metastatic tumor cells were extracted from subcutaneous tumor and lung of cancerous mice, respectively. MTT assay was used to determine the effect of curcumin on viability of tumor cells. Quantitative real-time polymerase chain reaction was performed to analyze the effect of curcumin on death receptor-5 (DR-5) gene expression. Results: Our data revealed that, compared with primary tumor cells, metastatic tumor cells were more resistance to apoptosis effects of curcumin. The DR-5 gene expression was up-regulated in both primary and metastatic tumor cells after curcumin treatment, but this up-regulation was significantly higher in primary tumor cells compared with metastatic cells. Conclusion: These findings provided important insights regarding the molecular mechanism of apoptosis resistance of metastatic tumor cells and can be used for designing a targeted therapeutic strategies in combat with metastatic TNBC.

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.

Inhibition of euchromatin histone-lysine N-methyltransferase 2 sensitizes breast cancer cells to tumor necrosis factor-related apoptosis-inducing ligand through reactive oxygen species-mediated activating transcription factor 4-C/EBP homologous protein-death receptor 5 pathway activation

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been characterized as an anti-cancer therapeutic agent with prominent cancer cell selectivity over normal cells. However, breast cancer cells are generally resistant to TRAIL, thus limiting its therapeutic potential. In this study, we found that BIX-01294, a selective inhibitor of euchromatin histone methyltransferase 2/G9a, is a strong TRAIL sensitizer in breast cancer cells. The combination of BIX-01294 and TRAIL decreased cell viability and led to an increase in the annexin V/propidium iodide-positive cell population, DNA fragmentation, and caspase activation. BIX-01294 markedly increased death receptor 5 (DR5) expression, while silencing of DR5 using small interfering RNAs abolished the TRAIL-sensitizing effect of BIX-01294. Specifically, BIX-01294 induced C/EBP homologous protein (CHOP)-mediated DR5 gene transcriptional activation and DR5 promoter activation was induced by upregulation of the protein kinase R-like endoplasmic reticulum kinase-mediated activating transcription factor 4 (ATF4). Moreover, inhibition of reactive oxygen species by N-acetyl-L-cysteine efficiently blocked BIX-01294-induced DR5 upregulation by inhibiting ATF4/CHOP expression, leading to diminished sensitization to TRAIL. These findings suggest that BIX-01294 sensitizes breast cancer cells to TRAIL by upregulating ATF4/CHOP-dependent DR5 expression with a reactive oxygen species-dependent manner. Furthermore, combination treatment with BIX-01294 and TRAIL suppressed tumor growth and induced apoptosis in vivo. In conclusion, we found that epigenetic regulation can contribute to the development of resistance to cancer therapeutics such as TRAIL, and further studies of unfolded protein responses and the associated epigenetic regulatory mechanisms may lead to the discovery of new molecular targets for effective cancer therapy.

Curcumin induces apoptosis and inhibits proliferation in infantile hemangioma endothelial cells via downregulation of MCL-1 and HIF-1α

BACKGROUND

Curcumin has been used as an alternative medicine for the treatment of infantile hemangiomas (IHs); however, the mechanism underlying the effectiveness of curcumin in IHs remains largely unclear.

METHODS

In this study, we isolated primary human hemangioma endothelial cells (HemECs) from fresh surgical specimens of 3 patients. We treated HemECs by curcumin and investigated the alterations in proliferative and apoptotic signaling pathways with cell counting kit-8, flow cytometry, western blotting, immunofluorescence, and real-time polymerase chain reaction.

RESULTS AND CONCLUSION

We found that curcumin potently inhibited proliferation in HemECs, achieving low-micromolar IC50 (the half maximal inhibitory concentration) value. We also observed that treatment with curcumin induced apoptosis in HemECs, as evidenced by positively Annexin-V-FITC staining, caspase-3 activation, and cleavage of poly(adenosine diphosphate-ribose) polymerase (PARP) in the treated cells. Moreover, we showed that curcumin suppressed the expression of antiapoptotic protein myeloid cell leukemia-1 (MCL-1), hypoxia-inducible factor 1α (HIF-1α), and vascular endothelial growth factor (VEGF).Altogether, our study suggests that the effectiveness of curcumin in IHs may be associated with its potent antiproliferative and apoptotic activities in HemECs.

Juglone potentiates TRAIL‑induced apoptosis in human melanoma cells via activating the ROS‑p38‑p53 pathway

Tumor necrosis factor‑related apoptosis‑inducing ligand (TRAIL)‑based cancer therapy offers promise as TRAIL can kill cancer cells without apparent toxicity towards normal cells. However, intrinsic or acquired resistance to TRAIL inseveral types of cancer cell has become a major challenge in TRAIL‑based cancer therapy. Juglone is a natural compound isolated from walnut trees. In the present study, it was demonstrated that juglone sensitized melanoma cells to TRAIL‑induced cytotoxicity by MTT and crystal violet assays. Flow cytometry analysis indicated that juglone potentiated TRAIL‑induced cell death. Western blot assay demonstrated that the expressions of cleaved poly(ADP‑ribose) polymerase (PARP) and cleaved caspase 3 were markedly increased in the juglone combined with TRAIL group. Exposure to TRAIL alone did not induce the production of reactive oxygen species (ROS), activation of p38 orincrease of p53 in the TRAIL‑resistant melanoma cells, as determined by flow cytometry and western blot analysis. However, exposure to TRAIL in combination with juglone markedly increased the production of ROS, activated p38 and increased p53, compared with the cells treated with either juglone or TRAIL alone. Pretreatment with N‑acetyl cysteine, a ROS scavenger, significantly reduced the cytotoxicity of juglone in combination with TRAIL, which further supported that ROS was involved in the juglone‑induced sensitization of TRAIL. In conclusion, juglone potentiated TRAIL‑induced apoptosis in melanoma cells, and these effects were partially mediated through the ROS‑p38‑p53 pathway. These findings suggested that juglone may be a potential sensitizer for TRAIL therapy in the treatment of melanoma.

Curcumin: the spicy modulator of breast carcinogenesis

Worldwide breast cancer is the most common cancer in women. For many years clinicians and the researchers are examining and exploring various therapeutic modalities for breast cancer. Yet the disease has remained unconquered and the quest for cure is still going on. Present-day strategy of breast cancer therapy and prevention is either combination of a number of drugs or a drug that modulates multiple targets. In this regard natural products are now becoming significant options. Curcumin exemplifies a promising natural anticancer agent for this purpose. This review primarily underscores the modulatory effect of curcumin on the cancer hallmarks. The focus is its anticancer effect in the complex pathways of breast carcinogenesis. Curcumin modulates breast carcinogenesis through its effect on cell cycle and proliferation, apoptosis, senescence, cancer spread and angiogenesis. Largely the NFkB, PI3K/Akt/mTOR, MAPK and JAK/STAT are the key signaling pathways involved. The review also highlights the curcumin mediated modulation of tumor microenvironment, cancer immunity, breast cancer stem cells and cancer related miRNAs. Using curcumin as a therapeutic and preventive agent in breast cancer is perplexed by its diverse biological activity, much of which remains inexplicable. The information reviewed here should point toward potential scope of future curcumin research in breast cancer.

Resveratrol and curcumin as protective agents in an experimental rat model of intestinal ischemia and reperfusion

The aim of this study was to evaluate the protective effects of resveratrol and curcumin in an experimental rat model of intestinal ischemia–reperfusion (I/R). Forty-eight adult Wistar rats were used: 12 animals undergoing the sham surgery and 36 animals undergoing laparotomy, with 15 min of mesentric artery clamping. The animals from the latter group (n = 12) were pretreated, for 1 week, with vehicle (CTR), resveratrol (RES), and curcumin (CUR). After 1 h and 6 h of reperfusion, respectively, cyclooxigenase (COX)-2, mucin-1, E-cadherin, nuclear factor (NK)-κB expressions, and tumor necrosis factor related apoptosis-inducing ligand (TRAIL) were assessed in the small intestine. Oxidative stress markers were determined in tissue homogenate and serum, and histopathological analysis was performed. Pretreatment with RES decreased the expression of COX-2 and NF-κB at both intervals and increased E-cadherin (p < 0.05) and mucin-1 production after 1 h. CUR had a beneficial effect on COX-2, NF-κB, and E-cadherin expressions, both after 1 h and after 6 h (p < 0.0001). The two compounds increased TRAIL levels and had a protective effect on oxidative stress and histopathological lesions, both after 1 h and after 6 h. Our results suggested that RES and CUR had beneficial effects in intestinal I/R and may represent a promising option for complementary treatment of this pathological condition.

STAT3 activity regulates sensitivity to tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis in cervical cancer cells

In cervical cancer, p53-induced apoptosis is abrogated by human papilloma virus (HPV)-derived oncoprotein E6. Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) provides tumor-specific apoptosis in various cancers, including cervical cancer, the sensitivity differs depending on the cell lines. Signal transducer and activator of transcription 3 (STAT3) is a hub molecule that shifts the cellular fate to apoptosis or survival in response to cellular stresses. However, the contribution of STAT3 activity to TRAIL-induced apoptosis in cervical cancer remains unknown. We examined the TRAIL sensitivity in cervical cancer cells, using TRAIL-resistant (SiHa) and -sensitive (CaSki) cervical cancer cell lines and focused on STAT3 function involving the apoptotic pathway. STAT3 was inactivated by TRAIL stimulation in the CaSki cell line, but not in the SiHa cell line. We then inhibited STAT3 expression in the SiHa cell line using siRNA against STAT3 and suppressed STAT3 activity using a STAT3 inhibitor; both these treatments sensitized TRAIL-induced apoptosis in the SiHa cell line. Furthermore, the SiHa cells were exposed to tunicamycin (TM), an endoplasmic reticulum (ER) stress inducer that inactivates STAT3, with or without TRAIL. Accompanied by STAT3 inactivation, TM pretreatment significantly enhanced TRAIL-induced apoptosis. We therefore concluded that TRAIL-induced apoptosis was regulated by STAT3 in response to TRAIL stimulation. Our results also suggest that STAT3 inhibition increases the sensitivity of malignancies, particularly HPV-related cancer, to TRAIL-based therapy.

Curcumin in Treating Breast Cancer: A Review

Breast cancer is among the most common malignant tumors. It is the second leading cause of cancer mortality among women in the United States. Curcumin, an active derivative from turmeric, has been reported to have anticancer and chemoprevention effects on breast cancer. Curcumin exerts its anticancer effect through a complicated molecular signaling network, involving proliferation, estrogen receptor (ER), and human epidermal growth factor receptor 2 (HER2) pathways. Experimental evidence has shown that curcumin also regulates apoptosis and cell phase-related genes and microRNA in breast cancer cells. Herein, we review the recent research efforts in understanding the molecular targets and anticancer mechanisms of curcumin in breast cancer.

Tanshinone IIA induces TRAIL sensitization of human lung cancer cells through selective ER stress induction

Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promised anticancer medicine targeting only the tumor, most cancers show resistance to TRAIL-induced apoptosis. For this reason, new therapeutic strategies to overcome the TRAIL resistance are required for more effective tumor treatment. In the present study, potential of tanshinone IIA as a TRAIL sensitizer was evaluated in human non-small cell lung cancer (NSCLC) cells. NSCLC cells showed resistance to TRAIL-mediated cell death, but combination treatment of Tanshinone IIA and TRAIL synergistically decreased cell viability and increased apoptosis in TRAIL-resistant NSCLC cells. Tanshinone IIA greatly induced death receptor 5 (DR5), but not death receptor 4 (DR4). Furthermore, DR5 knockdown attenuated the combination treatment of tanshinone IIA with TRAIL-mediated cell death in human NSCLC cells. Tanshinone IIA also increased CHOP and activated the PERK-ATF4 pathway suggesting that tanshinone IIA increased DR5 and CHOP by activating the PERK-ATF4 pathway. Tanshinone IIA also downregulated phosphorylation of STAT3 and expression of survivin. Taken together, these results indicate that tanshinone IIA increases TRAIL-induced cell death via upregulating DR5 and downregulating survivin mediated by, respectively, selective activation of PERK/ATF4 and inhibition of STAT3, suggesting combinatorial intervention of tanshinone IIA and TRAIL as a new therapeutic strategy for human NSCLC.

Decursin enhances TRAIL-induced apoptosis through oxidative stress mediated- endoplasmic reticulum stress signalling in non-small cell lung cancers

BACKGROUND AND PURPOSE

The TNF-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent due to its remarkable ability to selectively kill tumour cells. However, because most tumours exhibit resistance to TRAIL-induced apoptosis, the development of combination therapies to overcome resistance to TRAIL is required for effective cancer therapy.

EXPERIMENTAL APPROACH

Cell viability and possible synergy between the plant pyranocoumarin decursin and TRAIL was measured by MTT assay and calcusyn software. Reactive oxygen species (ROS) and apoptosis were measured using dichlorodihydrofluorescein and annexin/propidium iodide in cell flow cytometry. Changes in protein levels were assessed with Western blotting.

KEY RESULTS

Combining decursin and TRAIL markedly decreased cell viability and increased apoptosis in TRAIL-resistant non-small-cell lung cancer (NSCLC) cell lines. Decursin induced expression of the death receptor 5 (DR5). Inhibition of DR5 attenuated apoptotic cell death in decursin + TRAIL treated NSCLC cell lines. Interestingly, induction of DR5 and CCAAT/enhancer-binding protein homologues protein by decursin was mediated through selective induction of the pancreatic endoplasmic reticulum kinase (PERK)/activating transcription factor 4 (ATF4) branch of the endoplasmic reticulum stress response pathway. Furthermore, enhancement of PERK/ATF4 signalling by decursin was mediated by ROS generation in NSCLC cell lines, but not in normal human lung cells. Decursin also markedly down-regulated expression of survivin and Bcl-xL in TRAIL-resistant NSCLC cells.

CONCLUSIONS AND IMPLICATIONS

ROS generation by decursin selectively activated the PERK/ATF4 axis of the endoplasmic reticulum stress signalling pathway, leading to enhanced TRAIL sensitivity in TRAIL-resistant NSCLC cell lines, partly via up-regulation of DR5.

Morusin Induces TRAIL Sensitization by Regulating EGFR and DR5 in Human Glioblastoma Cells

Glioblastoma is one of the most malignant primary tumors, and the prognosis for glioblastoma patients remains poor. Tumor-necrosis-factor-related apoptosis-inducing ligand (TRAIL) is considered a promising anticancer agent due to its remarkable ability to selectively kill tumor cells. However, since many cancers are resistant to TRAIL, strategies to overcome resistance are required for the successful use of TRAIL in the clinic. In the present study, the potential of morusin as a TRAIL sensitizer in human glioblastoma cells was evaluated. Treatment with TRAIL or morusin alone showed weak cytotoxicity in human glioblastoma cells. However, combination treatment of TRAIL with morusin synergistically decreased cell viability and increased apoptosis compared with single treatment. Morusin induced expression of death receptor 5 (DR5), but not DR4 or decoy receptors (DcR1 and DcR2). Furthermore, morusin significantly decreased anti-apoptotic molecules survivin and XIAP. In addition, morusin reduced expression of EGFR and PDFGR as well as phosphorylation of STAT3, possibly mediating down-regulation of survivin and XIAP. Together these results suggest that morusin enhances TRAIL sensitivity in human glioblastoma cells through regulating expression of DR5 and EGFR. Therefore, the combination treatment of TRAIL and morusin may be a new therapeutic strategy for malignant glioma patients.

Curcumin Induces Pancreatic Adenocarcinoma Cell Death Via Reduction of the Inhibitors of Apoptosis

OBJECTIVES

The inhibitor of apoptosis (IAP) proteins are critical modulators of chemotherapeutic resistance in various cancers. To address the alarming emergence of chemotherapeutic resistance in pancreatic cancer, we investigated the efficacy of the turmeric derivative curcumin in reducing IAP protein and mRNA expression resulting in pancreatic cancer cell death.

METHODS

The pancreatic adenocarcinoma cell line PANC-1 was used to assess curcumin's effects in pancreatic cancer. Curcumin uptake was measured by spectral analysis and fluorescence microscopy. AlamarBlue and Trypan blue exclusion assays were used to determine PANC-1 cell viability after curcumin treatment. Visualization of PANC-1 cell death was performed using Hoffman Modulation Contrast microscopy. Western blot, and polymerase chain reaction analyses were used to evaluate curcumin's effects on IAP protein and mRNA expression.

RESULTS

Curcumin enters PANC-1 cells and is ubiquitously present within the cell after treatment. Furthermore, curcumin reduces cell viability and induces morphological changes characteristic of cell death. Additionally, curcumin decreases IAP protein and mRNA expression in PANC-1 cells.

CONCLUSIONS

These data demonstrate that PANC-1 cells are sensitive to curcumin treatment. Futthermore, curcumin is a potential therapeutic tool for overcoming chemotherapeutic resistance mediated by IAPs. Together, this data supports a role for curcumin as part of the therapeutic approach for the treatment of pancreatic cancer.

Recent Advances of Curcumin and its Analogues in Breast Cancer Prevention and Treatment

More than 230,000 diagnosed cases of invasive breast cancer in women was estimated in 2014 and an expected 40,000 deaths attributed to the aggressive carcinoma. An effective approach to diminish the morbidity and mortality of breast cancer is the development of chemopreventive and chemotherapeutic agents. Nutraceuticals have demonstrated their ability to proficiently halt carcinogenesis. The administration of natural compounds able to effectively serve as chemoprevention and chemotherapeutics without causing harm or adverse effects is imperative. Curcumin derived from the rhizome of Curcuma longa L., is a common spice of India, used for centuries because of its medicinal properties. The main component of curcumin possesses a wide range of biological activities; anti-proliferative, anti-inflammatory, and apoptotic characteristics modulated through the inactivation of pathways such as EGK and Akt/mTOR. In addition, curcumin alters the expression of cytokines, transcription factors, and enzymes involved in cell vitality. The in vivo application of curcumin in breast cancer is hindered by its limited bioavailabiity. The synthesis of curcumin analogues and delivery via nanoparticles has demonstrated enhanced bioavailability of curcumin in the malignancy. This review focuses on recent developments in the use of curcumin, curcumin analogues, and novel delivery systems as a preventive and therapeutic method for breast cancer.

Anticancer effect of tectochrysin in colon cancer cell via suppression of NF-kappaB activity and enhancement of death receptor expression

Background

Flavonoids are a diverse family of natural phenolic compounds commonly found in fruits and vegetables. Epidemiologic studies showed that flavonoids also reduce the risk of colon cancer. Tectochrysin is one of the major flavonoids of Alpinia oxyphylla Miquel. However, the anti-cancer effects and the molecular mechanisms of tectochrysin in colon cancer cells have not yet been reported. We investigated whether tectochrysin could inhibit colon cancer cell growth at 1, 5, 10 μg/ml. In in vivo study, we injected a tectochrysin treatment dose of 5 mg/kg to each mouse.

Results

Tectochrysin suppressed the growth of SW480 and HCT116 human colon cancer cells. The expression of DR3, DR4 and Fas were significantly increased, and pro-apoptotic proteins were also increased. Tectochrysin treatment also inhibited activity of NF-κB. A docking model indicated that tectochrysin binds directly to the p50 unit. In in vivo, tumor weights and volumes in mice were reduced when treated with tectochrysin. Tectochrysin leads to apoptotic cell death in colon cancer cells through activation of death receptors expression via the inhibition of NF-κB.

Conclusions

Tectochrysin can be a useful agent for the treatment of colon cancer cell growth as well as an adjuvant agent for chemo-resistant cancer cells growth.

Anticancer Activity of Curcumin on Human Breast Adenocarcinoma: Role of Mcl-1 Gene

Background:

Breast cancer is the second leading cause of cancer-related death among females in the world. To date, chemotherapy has been the most frequently used treatment for breast cancer and other cancers. However, some natural products have been used, as alternative treatments for cancers including breast cancer, due to their wide range of biological activities and low toxicity in animal models.

Objectives:

The present study examined the anti-proliferative activity of curcumin and its effect(s) on the apoptosis of breast cancer cells.

Materials and Methods:

This study was performed by an in vitro assay and the anticancer effects of curcumin were determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide). We used quantitative real time Polymerase Chain Reaction (PCR) for detection of Mcl-1 gene expression in treated groups and then compared them to control samples.

Results:

In the treatment group, there were higher levels of cell death changes than the control group. The results also showed that the Mcl-1 gene expression declined in the tested group as compared to the control group.

Conclusions:

Our present findings indicated that curcumin significantly inhibited the growth of human breast cancer cell MCF-7 by inducing apoptosis in a dose- and time- dependent manner, accompanied by a decrease in MCF-7 cell viability. Furthermore, our results showed that quantitative real-time PCR could be used as a direct method for detection Mcl-1 gene expression in tested samples and normal samples.

In Vitro Assessment of the Anticancer Potential of Evodiamine in Human Oral Cancer Cell Lines

Evodiamine, a bioactive alkaloid, has been regarded as having antioxidant, antiinflammatory, and anticancer properties. In the present study, we explored the effects of evodiamine on cell growth and apoptosis in human oral cancer cell lines. Our data revealed that evodiamine significantly inhibited the proliferation of human oral cancer cells and resulted in the cleavages of PARP (poly (ADP-ribose) polymerase) and caspase-3, in addition to causing the typical characteristics of apoptosis. Evodiamine also increased Bax protein levels and caused translocation of Bax into mitochondria and Bax oligomerization. In addition, evodiamine decreased expression of myeloid cell leukemia (Mcl-1) at the transcriptional modification, and knockdown of Mcl-1 clearly resulted in an increase in expression of Bax and active Bax, resulting in induction of apoptosis. Evodiamine reduced expression of phosphorylated AKT, and LY294002 potentiated evodiamine-induced apoptosis by regulating Mcl-1 protein. Our results suggest that evodiamine induces apoptosis in human oral cancer cells through the AKT pathway. These findings provide a rationale for its clinical application in the treatment of oral cancer.

Curcumin conjugated with PLGA potentiates sustainability, anti-proliferative activity and apoptosis in human colon carcinoma cells

Curcumin, an ingredient of turmeric, exhibits a variety of biological activities such as anti-inflammatory, anti-atherosclerotic, anti-proliferative, anti-oxidant, anti-cancer and anti-metastatic. It is a highly pleiotropic molecule that inhibits cell proliferation and induces apoptosis in cancer cells. Despite its imperative biological activities, chemical instability, photo-instability and poor bioavailability limits its utilization as an effective therapeutic agent. Therefore, enhancing the bioavailability of curcumin may improve its therapeutic index for clinical setting. In the present study, we have conjugated curcumin with a biodegradable polymer Poly (D, L-lactic-co-glycolic acid) and evaluated its apoptotic potential in human colon carcinoma cells (HCT 116). The results show that curcumin-PLGA conjugate efficiently inhibits cell proliferation and cell survival in human colon carcinoma cells as compared to native curcumin. Additionally, curcumin conjugated with PLGA shows improved cellular uptake and exhibits controlled release at physiological pH as compared to native curcumin. The curcumin-PLGA conjugate efficiently activates the cascade of caspases and promotes intrinsic apoptotic signaling. Thus, the results suggest that conjugation potentiates the sustainability, anti-proliferative and apoptotic activity of curcumin. This approach could be a promising strategy to improve the therapeutic index of cancer therapy.

Curcumin a potent cancer preventive agent: Mechanisms of cancer cell killing

There is no doubt that diet could effectively improve health and halt cancers. Dietary phytochemical compounds and their derivatives represent a cornucopia of effectively anticancer compounds. This review discusses existing data on the anticancer activities of curcumin, and then offers possible explanations for and mechanisms of its cancer-preventive action. This review also offers insights into the molecular mechanism and targets through which curcumin modulates cell cycle, apoptotic signals, anti-apoptotic proteins, miRNAs, Wnt/beta-catenin signaling, protein kinases, nuclear factor-κB, proteasome activation, epigenetic regulation including DNA methylation and histone modification. Finally, this review provides explanations for how curcumin reverses the multi-drug resistance (MDR) of cancer cells.

Evodiamine induces apoptosis and enhances TRAIL-induced apoptosis in human bladder cancer cells through mTOR/S6K1-mediated downregulation of Mcl-1

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), either alone or in combination with other anti-cancer agents, has been considered as a new strategy for anti-cancer therapy. In this study, we demonstrated that evodiamine, a quinolone alkaloid isolated from the fruit of Evodia fructus, induced apoptosis and enhanced TRAIL-induced apoptosis in human bladder cancer cells. To elucidate the underlying mechanism, we found that evodiamine significantly reduced the protein levels of Mcl-1 in 253J and T24 bladder cancer cells, and overexpression of this molecule attenuated the apoptosis induced by evodiamine alone, or in combination with TRAIL. Further experiments revealed that evodiamine did not affect the mRNA level, proteasomal degradation and protein stability of Mcl-1. On the other hand, evodiamine inhibited the mTOR/S6K1 pathway, which usually regulates protein translation; moreover, knockdown of S6K1 with small interfering RNA (siRNA) effectively reduced Mcl-1 levels, indicating evodiamine downregulates c-FLIP through inhibition of mTOR/S6K1 pathway. Taken together, our results indicate that evodiamine induces apoptosis and enhances TRAIL-induced apoptosis possibly through mTOR/S6K1-mediated downregulation of Mcl-1; furthermore, these findings provide a rationale for the combined application of evodiamine with TRAIL in the treatment of bladder cancer.