Thymoquinone inhibits tumor angiogenesis and tumor growth through suppressing AKT and extracellular signal-regulated kinase signaling pathways

Protein kinase A activation by the anti-cancer drugs ABT-737 and thymoquinone is caspase-3-dependent and correlates with platelet inhibition and apoptosis

Chemotherapy-induced thrombocytopenia is a common bleeding risk in cancer patients and limits chemotherapy dose and frequency. Recent data from mouse and human platelets revealed that activation of protein kinase A/G (PKA/PKG) not only inhibited thrombin/convulxin-induced platelet activation but also prevented the platelet pro-coagulant state. Here we investigated whether or not PKA/PKG activation could attenuate caspase-dependent apoptosis induced by the anti-cancer drugs ABT-737 (the precursor of navitoclax) and thymoquinone (TQ), thereby potentially limiting chemotherapy-induced thrombocytopenia. This is particularly relevant as activation of cyclic nucleotide signalling in combination chemotherapy is an emerging strategy in cancer treatment. However, PKA/PKG-activation, as monitored by phosphorylation of Vasodilator-stimulated phosphoprotein (VASP), did not block caspase-3-dependent platelet apoptosis induced by the compounds. In contrast, both substances induced PKA activation themselves and PKA activation correlated with platelet inhibition and apoptosis. Surprisingly, ABT-737- and TQ-induced VASP-phosphorylation was independent of cAMP levels and neither cyclases nor phosphatases were affected by the drugs. In contrast, however, ABT-737- and TQ-induced PKA activation was blocked by caspase-3 inhibitors. In conclusion, we show that ABT-737 and TQ activate PKA in a caspase-3-dependent manner, which correlates with platelet inhibition and apoptosis and therefore potentially contributes to the bleeding risk in chemotherapy patients.

Thymoquinone as a Potential Adjuvant Therapy for Cancer Treatment: Evidence from Preclinical Studies

Thymoquinone (TQ), the main bioactive component of Nigella sativa, has been found to exhibit anticancer effects in numerous preclinical studies. Due to its multitargeting nature, TQ interferes in a wide range of tumorigenic processes and counteracts carcinogenesis, malignant growth, invasion, migration, and angiogenesis. Moreover, TQ can specifically sensitize tumor cells toward conventional cancer treatments (e.g., radiotherapy, chemotherapy, and immunotherapy) and simultaneously minimize therapy-associated toxic effects in normal cells. In this review, we summarized the adjuvant potential of TQ as observed in various in vitro and in vivo animal models and discussed the pharmacological properties of TQ to rationalize its supplementary role in potentiating the efficacy of standard therapeutic modalities namely surgery, radiotherapy, chemotherapy, and immunotherapy. Altogether, we suggest further comprehensive evaluation of TQ in preclinical and clinical levels to delineate its implied utility as a novel complementary adjuvant therapy for cancer treatment.

Effectiveness of thymoquinone, zeolite, and platelet-rich plasma in model of corrosive oesophagitis induced in rats

Purpose

The effectiveness of platelet-rich plasma (PRP), thymoquinone, and zeolite in corrosive esophageal burns was investigated in a rat model.

Methods

Four groups were comprised as containing 10 rats in each group. For group I, oesophagitis was induced and no other procedure was performed (control group). For group II, oesophagitis was induced and thymoquinone was administered for 1 week via oral gavage once a day (thymoquinone group). For group III, oesophagitis was induced for 1 week via oral gavage once a day (PRP group). For group IV, oesophagitis was induced and zeolite was administered for 1 week via oral gavage once a day (zeolite group). On the 10th day, the rats were sacrificed under anaesthesia and venous blood sampling was performed from the vena portae. The oesophaguses were totally excised. Biochemically, interleukin (IL)-1B, IL-6, TNF-α, and MCP-1 were examined from venous blood. Inflammation score was evaluated histopathologically in oesophageal tissue that was collected.

Results

There was a statistically significant difference among groups in terms of IL-1, IL-6, MCP levels, compared to the control group; median IL-1, IL-6, MCP levels of thymoquinone, PRP, and zeolite groups were statistically significantly lower. There was a statistically significant difference among groups in terms of inflammation scores, compared to group I; median inflammation scores of groups II, III and IV were statistically significantly lower thymoquinone.

Conclusion

PRP, and zeolite exhibited positive effect on recovery in oesophagitis by reducing inflammation in the involved segment.

Eupafolin Exhibits Potent Anti-Angiogenic and Antitumor Activity in Hepatocellular Carcinoma

Eupafolin is a flavonoid extracted from the common sage herb which has been used in China as traditional medicine. Previous studies had reported that eupafolin had antioxidative, anti-inflammatory and antitumor effects. However, the function and the mechanism of eupafolin to exert its antitumor activity, especially its effect on tumor angiogenesis, have not been elucidated. Herein, we showed that eupafolin significantly inhibited vascular endothelial growth factor (VEGF)-induced cell proliferation, migration and tube formation of human umbilical vascular endothelial cells (HUVECs) in a dose-dependent manner. Meanwhile, the new blood microvessels induced by VEGF in the matrigel plug were also substantially suppressed by eupafolin. The results of HCC xenograft experiments demonstrated eupafolin remarkably inhibited tumor growth and tumor angiogenesis in vivo, suggesting the antitumor activity exerted by eupafolin was closely correlated with its potency on tumor angiogenesis. Mechanism investigations revealed that eupafolin significantly blocked VEGF-induced activation of VEGFR2 in HUVEC cells as well as its downstream signaling pathway. In addition to the effect on endothelial cells, through inhibiting Akt activity in tumor cells, VEGF secretion in HepG2 was dramatically decreased after eupafolin treatment. Our study was the first to report the activity of eupafolin against tumor angiogenesis as well as the underlying mechanism by which eupafolin to exert its anti-angiogenic activity.

Neoalbaconol inhibits angiogenesis and tumor growth by suppressing EGFR-mediated VEGF production

Neoalbaconol, derived from Albatrellus confluens, shows anti-cancer activities in the previously study, but its role in angiogenesis is unknown. Here, we determined whether neoalbaconol could attenuate angiogenesis and how does it occur. Data demonstrated that neoalbaconol could inhibit the proliferation of breast cancer cells and induce apoptosis. Also, neoalbaconol suppressed vascular endothelial growth factor (VEGF)-induced human umbilical vascular endothelial cells (HUVECs) proliferation, migration, invasion, and capillary-like tube formation in vitro and reduced tumor angiogenesis in vivo. VEGF receptor activation and the downstream signal transduction cascades activation were inhibited by neoalbaconol. Additionally, neoalbaconol blocked EGFR-mediated VEGF production. EGFR overexpression reversed the neoalbaconol-induced VEGF reduction, confirming the importance of the EGFR inhibition in anti-angiogenesis of neoalbaconol. Furthermore, neoalbaconol inhibited tumor growth and tumor angiogenesis in a breast cancer xenograft model in vivo. Taken together, these results indicate that neoalbaconol could inhibit tumor angiogenesis and growth through direct suppression effects on vascular endothelial cells and reduction of proangiogenic factors in cancer cells.

Thymoquinone, as an anticancer molecule: from basic research to clinical investigation

Thymoquinone is an anticancer phytochemical commonly found in black cumin. In this review, we discuss the potential of thymoquinone as anticancer molecule, its mechanism of action and future usage in clinical applications. Thymoquinone exhibits anticancer activity via numerous mechanisms of action, specifically by showing selective antioxidant and oxidant activity, interfering with DNA structure, affecting carcinogenic signaling molecules/pathways and immunomodulation. In vitro activity of thymoquinone has been further implicated in animal models of cancer; however, no clinical application has been proven yet. This is the optimum time to focus on clinical trials for developing thymoquinone as a future drug in cancer therapeutics.

Downregulation of PRDM1 promotes cellular invasion and lung cancer metastasis

The zinc-finger transcription factor PRDM1 (PR domain containing 1) plays key roles in the development of malignant lymphoma, leukaemia and some non-haematopoietic cancers, including breast cancer, colorectal cancer and glioma. However, little is known regarding the function of PRDM1 in the progression of lung cancer. Here, we found that PRDM1 is expressed in normal human lung epithelium but is downregulated in lung cancer cells. Decreased expression of PRDM1 correlates with poor prognosis in lung cancer. Depletion of PRDM1 in lung cancer cells promotes cellular invasion and anoikis resistance in vitro and lung metastasis in vivo. PRDM1 is silenced by an ectopically expressed lymphocyte-specific transcription factor Aiolos. The transcription of these two genes is negatively correlated in 206 lung epithelial cell lines. Our results indicate that PRDM1 functions as a tumour suppressor in lung cancer.

Role of traditional Islamic and Arabic plants in cancer therapy

ETHNO PHARMACOLOGICAL RELEVANCE

This review article underlines individual Traditional Islamic and Arabic plant (TAI) and their role in treating cancer. The aim of the study is to specifically evaluate the progress of herbs, Arabic and Islamic traditional herbs in particular, applied in cancer treatment, so far.

MATERIALS AND METHODS

Islamic and Arabic plants were selected and identified through different literature survey using "Google scholar", "Web of science", "Scopus" and "PubMed". Each plant, from identified Arabic and Islamic plants list, was search individually for the most cited articles in the aforementioned databases using the keywords, "Anticancer", "Uses in cancer treatment", "Ethno pharmacological importance in cancer" etc.

RESULTS

The current review about Islamic and Arabic plants illuminates the importance of Islamic and Arabic plants and their impact in treating cancer. There is a long list of Islamic and Arabic plants used in cancer as mentioned in review with enormous amount of literature. Each plant has been investigated for its anticancer potential. The literature survey as mentioned in table shows; these plants are widely utilized in cancer as a whole, a part thereof or in the form of isolated chemical constituent.

CONCLUSIONS

This review strongly supports the fact; Arabic and Islamic traditional plants have emerged as a good source of complementary and alternative medicine in treating cancer. Traditional Arab-Islamic herbal-based medicines might be promising for new cancer therapeutics with low toxicity and minimal side effects. The plants used are mostly in crude form and still needs advance research for the isolation of phytochemicals and establishing its cellular and molecular role in treating cancer.

Thymoquinone inhibits the migration of mouse neuroblastoma (Neuro-2a) cells by down-regulating MMP-2 and MMP-9

Thymoquinone (TQ), an active component derived from the medial plant Nigella sativa, has been used for medical purposes for more than 2 000 years. Recent studies have reported that TQ blocked angiogenesis in animal model and reduced migration, adhesion, and invasion of glioblastoma cells. We have recently shown that TQ could exhibit a potent cytotoxic effect and induce apoptosis in mouse neuroblastoma (Neuro-2a) cells. In the present study, TQ treatment markedly decreased the adhesion and migration of Neuro-2a cells. TQ down-regulated MMP-2 and MMP-9 protein expression and mRNA levels and their activities. Furthermore, TQ significantly down-regulated the protein expression of transcription factor NF-κB (p65) but not significantly altered the expression of N-Myc. Taken together, our data indicated that TQ's inhibitory effect on the migration of Neuro-2a cells was mediated through the suppression of MMP-2 and MMP-9 expression, suggesting that TQ treatment can be a promising therapeutic strategy for human malignant neuroblastoma.

Thymoquinone: An IRAK1 inhibitor with in vivo and in vitro anti-inflammatory activities

Thymoquinone (TQ) is a bioactive component of black seed (Nigella sativa) volatile oil and has been shown to have anti-oxidative, anti-inflammatory, and anti-cancer properties. In the present study, we explored the molecular mechanisms that underlie the anti-inflammatory effect of TQ and its target proteins using lipopolysaccharide (LPS)-stimulated murine macrophage-like RAW264.7 and human monocyte-like U937 cells, together with LPS/D-galactosamine (GalN)-induced acute hepatitis and HCl/EtOH-induced gastritis mouse models. TQ strongly inhibited the production of nitric oxide (NO) and repressed NO synthase (iNOS), tumor necrosis factor (TNF)-α, cyclooxygenase (COX)−2, interleukin (IL)−6, and IL-1β expression in LPS-activated RAW264.7 cells. Treatment of LPS/D-GalN–induced hepatitis and EtOH/HCl–induced gastritis mouse models with TQ significantly ameliorated disease symptoms. Using luciferase reporter gene assays, we also showed that the nuclear levels of transcription factors and phosphorylation patterns of signaling proteins, activator protein (AP)−1, and nuclear factor (NF)-κB pathways were all affected by TQ treatment. Finally, we used additional kinase and luciferase validation assays with interleukin-1 receptor-associated kinase 1 (IRAK1) to show that IRAK1 is directly suppressed by TQ treatment. Together, these findings strongly suggest that the anti-inflammatory actions of TQ are caused by suppression of IRAK-linked AP-1/NF-κB pathways.

Thymoquinone potentiates chemoprotective effect of Vitamin D3 against colon cancer: a pre-clinical finding

Prevention of colon cancer among high-risk group has been long lasting research goal. Emerging data have evidenced the anticancer activities of Vitamin D3 (Vit.D) and Thymoquinone (TQ). The aim of the current study was to evaluate the synergistic potential of Thymoquinone and Vitamin D3 in the control of colon cancer progression using azoxymethane-induced rat model. Vit.D and TQ were given individually or in combination 4 week prior to induction and continued for a total of 20 week. At the end of the study, all animals were euthanized and their resected colons were examined macroscopically and microscopically for tumor growth. Colonic tissue preparations were used for measuring gene expression and/or protein levels of selected pro and anti-tumor biomarkers using quantitative RT-PCR, ELISA and immunohistochemistry. Compared with their individual supplementation, combined Vit.D/TQ showed prominent anti-tumor effect manifested by significant reduction (P < 0.05) of the numbers of grown tumors and large aberrant crypts foci. Mechanistically, gene expression and/or protein quantification studies revealed that combined Vit.D/TQ supplementation induced significant reduction (P < 0.01 and P < 0.05) of pro-cancerous molecules (Wnt, β-catenin, NF-κB, COX-2, iNOS, VEGF and HSP-90) as well as significant increase (P < 0.01 and P < 0.05, respectively) of anti-tumorigenesis biomarkers (DKK-1, CDNK-1A, TGF-β1, TGF-β/RII and smad4) as compared to un-supplemented or individually supplemented groups, respectively. In conclusion, TQ augmented the chemopreventive effect of Vit.D during the initiation phase of colon cancer in rat model, with the potential to suppress progression of pre-neoplastic lesions in colon carcinogenesis.

Inhibition of NF-κB and metastasis in irinotecan (CPT-11)-resistant LoVo colon cancer cells by thymoquinone via JNK and p38

Clinically used chemotherapeutics can effectively eliminate most tumor cells. However, they cause unwanted side effects and result in chemoresistance. To overcome such problems, phytochemicals are now used to treat cancers by means of targeted therapy. Thymoquinone (TQ) is used to treat different cancers (including colon cancer) and is an NF-κB inhibitor. Irinotecan resistant (CPT-11-R) LoVo colon cancer cell line was previous constructed by step-wise CPT-11 challenges to un-treated parental LoVo cells and expresses EGFR/IKKα/β/NF-κB pathway. TQ resulted in reduced total and phosphorylation of IKKα/β and NF-κB and decreased metastasis in CPT-11-R cells. TQ not only reduced activity of ERK1/2 and PI3K but also activated JNK and p38. Furthermore, TQ was also found to suppress metastasis through activation of JNK and p38. Therefore, TQ suppressed metastasis through NF-κB inhibition and activation of JNK and p38 in CPT-11-R LoVo colon cancer cells. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 669-678, 2017.

Anticancer Chemodiversity of Ranunculaceae Medicinal Plants: Molecular Mechanisms and Functions

The buttercup family, Ranunculaceae, comprising more than 2,200 species in at least 62 genera, mostly herbs, has long been used in folk medicine and worldwide ethnomedicine since the beginning of human civilization. Various medicinal phytometabolites have been found in Ranunculaceae plants, many of which, such as alkaloids, terpenoids, saponins, and polysaccharides, have shown anti-cancer activities in vitro and in vivo. Most concerns have been raised for two epiphany molecules, the monoterpene thymoquinone and the isoquinoline alkaloid berberine. At least 17 genera have been enriched with anti-cancer phytometabolites. Some Ranunculaceae phytometabolites induce the cell cycle arrest and apoptosis of cancer cells or enhance immune activities, while others inhibit the proliferation, invasion, angiogenesis, and metastasis, or reverse the multi-drug resistance of cancer cells thereby regulating all known hallmarks of cancer. These phytometabolites could exert their anti-cancer activities via multiple signaling pathways. In addition, absorption, distribution, metabolism, and excretion/toxicity properties and structure/activity relationships of some phytometabolites have been revealed assisting in the early drug discovery and development pipelines. However, a comprehensive review of the molecular mechanisms and functions of Ranunculaceae anti-cancer phytometabolites is lacking. Here, we summarize the recent progress of the anti-cancer chemo- and pharmacological diversity of Ranunculaceae medicinal plants, focusing on the emerging molecular machineries and functions of anti-cancer phytometabolites. Gene expression profiling and relevant omics platforms (e.g. genomics, transcriptomics, proteomics, and metabolomics) could reveal differential effects of phytometabolites on the phenotypically heterogeneous cancer cells.

Antiproliferative and Apoptosis-Inducing Activities of Thymoquinone in Lymphoblastic Leukemia Cell Line

Acute lymphoblastic leukemia is one of the malignant proliferations of lymphoid cells in the early stages of differentiation and accounts for about 80% of all cases of childhood leukemia. Side effects of available treatment are still main concern. Thymoquinone (TQ), a natural compound isolated from Nigella sativa, induces growth inhibition and apoptosis in several cancer cell lines. The aim of the present study was to investigate the effect of TQ alone and in combination with doxorubicine on the proliferation inhibition and apoptosis induction of TQ in a lymphoblastic leukemia cell line. Jurkat cell line was cultured in standard condition and with concentrations of TQ (0-30 μm) and doxorubicine for 24, 48 and 72 h. Cell viability was measured by MTS assay. Apoptosis induction by TQ was assessed by annexin V-FITC/PI and flow cytometry analysis. TQ and DOX decreased cell viability with a time and dose dependent manner. The IC50 values were 19.461 ± 1.141, 17.342 ± 1.949 and 14.123 ± 1.874 μM in 24, 48 and 72 h, respectively for TQ. IC50 values for DOX were. 075 ± .0124, .028 ± .007 and.007 ± .001 μM in 24, 48 and 72 h, respectively. The level of cell apoptosis in all used concentrations of TQ (4, 8, 12, 16 and 20 μm) was higher than control group (10.2, 14.1, 36.6, 87.5 and 93.3% respectively after 24 h; 10.7, 13.9, 64.6, 92.2 and 93.1 respectively after 48 h; 2.83, 5.83, 41.4, 71.6 and 86.6% respectively after 72 h) and reached to a significant level at 12, 16 and 20 μm concentration for 24 and 48 h and 16 and 20 μm for 72 h incubation. Combination of doxorubicine and TQ lead to a synergistic cytotoxicity as compared to any of them alone. The study indicated that TQ is effective on proliferation inhibition and is a strong apoptotic inducer in Jurkat lymphoblastic cell line and has synergistic effect in combination with DOX. This combination strategy can be an alternative way for more powerful anticancer effects. Therefore, the study of the mechanism of apoptosis induction of TQ can be a step forward to in target therapy which might be considered in the future studies.

Targeting Twist expression with small molecules

Twist, as one of the important embryonic transcription factors, regulates epithelial-mesenchymal transition (EMT) and migration in embryo formation and cancer development. Both Twist-1 and Twist-2 are rarely detectable in healthy adult tissues, but are frequently overexpressed in multiple kinds of human cancer tissues, such as breast, prostate, uterus, liver, melanoma, etc. Twist is considered as a crucial EMT inductor and correlated with carcinoma aggression, invasion and metastasis. In the past decades, in-depth investigation has been reported in terms of the role of Twist in cancers; in addition, several kinds of small molecules have played important roles in studying the effect of Twist on cancer development, suggesting that Twist can be regarded as one of the important potential targets for cancer treatment. Hence we provide a brief overview of Twist and several small molecules targeting its expression, highlighting the biological features that make it a charming target for cancer therapy.

In Vitro Anti-Neuroblastoma Activity of Thymoquinone Against Neuro-2a Cells via Cell-cycle Arrest

We have recently shown that thymoquinone (TQ) has a potent cytotoxic effect and induces apoptosis via caspase-3 activation with down-regulation of XIAP in mouse neuroblastoma (Neuro-2a) cells. Interestingly, our results showed that TQ was significantly more cytotoxic towards Neuro-2a cells when compared with primary normal neuronal cells. In this study, the effects of TQ on cell-cycle regulation and the mechanisms that contribute to this effect were investigated using Neuro-2a cells. Cell-cycle analysis performed by flow cytometry revealed cell-cycle arrest at G2/M phase and a significant increase in the accumulation of TQ-treated cells at sub-G1 phase, indicating induction of apoptosis by the compound. Moreover, TQ increased the expression of p53, p21 mRNA and protein levels, whereas it decreased the protein expression of PCNA, cyclin B1 and Cdc2 in a dose- dependent manner. Our finding suggests that TQ could suppress cell growth and cell survival via arresting the cell-cycle in the G2/M phase and inducing apoptosis of neuroblastoma cells.

Insights into the molecular interactions of thymoquinone with histone deacetylase: evaluation of the therapeutic intervention potential against breast cancer

Many HDAC inhibitors have passed through the gateway of clinical trials. However, they have limited therapeutic implications due to their pleiotropic pharmaceutical properties and off-target effects. In view of this, dietary active phytochemicals were evaluated. Based upon the chemical and structural insights of HDAC active pockets, thymoquinone (TQ) was investigated to uncover its active participation in HDAC inhibition. The synergistic analysis of docking and molecular dynamics simulation disclosed the elementary interaction and stability of TQ with human HDACs. The in silico findings were corroborated with an in vitro analysis, demonstrating the efficient role of TQ in the attenuation of global HDAC activity. Furthermore, TQ also elicited downstream effects of HDAC inhibition: reactivation of HDAC target genes (p21 and Maspin), induction of the pro-apoptotic gene Bax, down regulation of the anti-apoptotic gene Bcl-2 and arrest of the cell cycle at the G2/M phase. Finally, the result of a higher cytotoxicity of TQ towards MCF-7 breast cancer cells in comparison to normal cells indicates the potential of TQ to be an anticancer drug.

Anticancer activity of an ultrasonic nanoemulsion formulation of Nigella sativa L. essential oil on human breast cancer cells

Nigella sativa L. (NS) is a plant renowned in traditional holistic medicine systems for almost 1400 years because of its remarkable antioxidant, antimicrobial, anti-inflammatory and anti-cancer properties. The essential oil of N. sativa, in particular, possesses these significant biological properties. However, N. sativa essential oil has many insoluble constituents with properties that have not been fully explored. Nanoemulsion-based insoluble formulations are a widely used carrier system for lipophilic materials. In the present study, we used ultrasonic emulsification, polysorbate 80 and water to formulate a highly stable N. sativa essential oil nanoemulsion (NSEO-NE). To optimize the NSEO-NE preparation, we changed the surfactant concentration, the oil-surfactant mixing ratio and the emulsification time. The droplet size distribution and morphology of the prepared NE was analyzed using dynamic light scattering and scanning electron microscopy, respectively. The droplet size of the NSEO-NE was approximately 20-50 nm in diameter. The anticancer properties of the NE preparation were studied using a modified methyl-thiazolyl-diphenyl tetrazolium bromide (MTT) assay as well as cellular uptake and nuclear morphological analyses. The NSEO-NE significantly reduced the viability of Michigan Cancer Foundation-7 (MCF-7) breast cancer cells. The nucleo-cytoplasmic morphological features of NSEO-NE-treated cells included cell membrane blebbing, cytoplasmic vacuolation, marginalization of chromatin, and fragmentation of the nucleus. The results clearly indicate that NSEO-NE induced apoptosis in MCF-7 cells. These findings support the potential application of NSEO-NE in breast cancer therapy, and also merit future translational research.

Thymoquinone Could Increase The Efficacy of Tamoxifen Induced Apoptosis in Human Breast Cancer Cells: An In Vitro Study

Objective

Thymoquinone (TQ), as the main component of Nigella Sativa plant, shows anticancer properties. This study was aimed to evaluate the combined effect of TQ and Tamoxifen (TAM) on viability and apoptosis of human breast cancer cell lines.

Materials and Methods

In this experimental study, estrogen positive MCF-7 and estrogen negative MDA-MB-231 human breast cancer cell lines were induced by TAM (2 µM) or different doses of TQ (50, 75, 100, 150 µM), individually or in combination. Cell viability and apoptosis were investigated by MTT assay and TdT-mediated deoxy-uracil nick end labeling (TUNEL) assay; Acridine orange (AO)/Ethidium bromide (EB) staining respectively. Data were analyzed by one way ANOVA and P<0.05 was considered significant.

Results

In 24 hours treatment, TAM and all doses of TQ, solely or in combination, significantly reduced cell viability of both cell lines, except in MCF-7 cells treated with 50 µM TQ, and MDA-MB-231 cells treated with 50 or 75 µM TQ (P<0.01). After 48 hours treatment, cell viability of both cell lines was reduced in all treated groups (P<0.05). Remarkable apoptotic index was observed in combination treatment of MCF-7 or MDA-MB-231 cell lines with TAM and TQ (P<0.001).

Conclusion

The synergistic effect of TQ and TAM on human breast cancer cell lines showed cell viability reduction as well as apoptosis induction, independent to estrogen.

Thymoquinone inhibits inflammation, neoangiogenesis and vascular remodeling in asthma mice

Asthma is a chronic obstructive disease which is characterized by recurring airway inflammation, reversible airway obstruction, airway hyper responsiveness and vascular remodeling. Thymoquinone (TQ), an active ingredient isolated from Nigella sativa, was reported to exhibit anti-inflammation and anti-proliferation of in various cancer cells as well as epithelial cells. The aim of this study was to evaluate the effect of TQ on the inflammation, neoangiogenesis and vascular remodeling induced by Ovalbumin (OVA) in asthma mice in vivo and the anti-angiogenesis effects of TQ in VEGF-induced human umbilical vein endothelial cells (HUVECs) in vitro. Our results revealed that TQ inhibited the production of inflammatory factors interleukin-4/-5 (IL-4/-5) by enzyme-linked immunesorbent assay (ELISA). Immunohistochemistry analysis showed that the increase of platelet endothelial cell adhesion molecule-1, which is also known as CD31 and α-smooth muscle actinalpha (α-SMA) expression in asthma mice challenged by OVA was suppressed by TQ. Moreover, TQ suppressed the activation of VEGFR2-PI3K-Akt pathway and up-regulated the expression of Slit glycoprotein-2 (Slit-2) both in vivo and in vitro with the inhibition of tube information in HUVEC cells. Meanwhile immunofluorescence analysis showed that Slit-2 and Roundabout-4 (Robo-4) were co-expressing after TQ treatment in OVA-challenged asthma mice. Our study demonstrates that TQ attenuated the inflammatory reaction by antagonizing IL-4/-5 while the anti-neoangiogenesis effect of TQ is mediated by inhibition of vascular endothelial growth factor (VEGF) expression through VEGFR2/PI3K/Akt signaling pathway, which supports a potential role for TQ in ameliorating asthma.

Thymoquinone inhibits cancer metastasis by downregulating TWIST1 expression to reduce epithelial to mesenchymal transition

Proteins that promote epithelial to mesenchymal transition (EMT) are associated with cancer metastasis. Inhibition of EMT regulators may be a promising approach in cancer therapy. In this study, Thymoquinone (TQ) was used to treat cancer cell lines to investigate its effects on EMT-regulatory proteins and cancer metastasis. We show that TQ inhibited cancer cell growth, migration and invasion in a dose-dependent manner. At the molecular level, TQ treatment decreased the transcriptional activity of the TWIST1 promoter and the mRNA expression of TWIST1, an EMT-promoting transcription factor. Accordingly, TQ treatment also decreased the expression of TWIST1-upregulated genes such as N-Cadherin and increased the expression of TWIST1-repressed genes such as E-Cadherin, resulting in a reduction of cell migration and invasion. TQ treatment also inhibited the growth and metastasis of cancer cell-derived xenograft tumors in mice but partially attenuated the migration and invasion in TWIST1-overexpressed cell lines. Furthermore, we found that TQ treatment enhanced the promoter DNA methylation of the TWIST1 gene in BT 549 cells. Together, these results demonstrate that TQ treatment inhibits TWIST1 promoter activity and decreases its expression, leading to the inhibition of cancer cell migration, invasion and metastasis. These findings suggest TQ as a potential small molecular inhibitor of cancer growth and metastasis.

In vitro and in vivo study of hydralazine, a potential anti-angiogenic agent

Hydralazine (HYD), an old routine clinical anti-hypertension drug, is rarely used in clinic nowadays. Since the strategy of repositioning old drugs was put forward, HYD has been reported to possess various biological activities, including antitumor efficacy and reducing intra-tumor microvessel. Here, we investigated that whether HYD had the ability of anti-angiogeneis and its underlying mechanism. Cells proliferation, wound-healing, Transwell migration and invasion, tube formation and rat aortic ring assays in vitro and chicken chorioallantoic membrane (CAM) model in vivo were designed to investigated HYD's anti-angiogenic effect. Levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were assessed by enzyme-linked immune sorbent assay (ELISA). Hepatocellular carcinoma (HCC) mice model was used to evaluate HYD's effect on tumor growth and microvessel density. Our results showed that HYD not only inhibited human umbilical vascular endothelial cell (HUVEC) proliferation, wound-healing, Transwell migration and invasion and tube formation, but also suppressed the microvessel outgrowth of rat aortic ring in vitro and the neovascularzation of CAM in vivo. Furthermore, we demonstrated that HYD attenuated tumor angiogenesis and tumor growth. In the co-culture system of Transwell migration, the secretion of VEGF and bFGF was reduced by HYD respectively. In sum, our data indicate that HYD has the pharmacological effect of ant-angiogenesis by interference with VEGF and bFGF signaling pathways in endothelial cells. These findings suggest that HYD might be a promising angiogenesis inhibitor and a potential effective therapeutic agent for cancer therapy.

Novel anti-cancer agent myrtucommulone-A and thymoquinone abrogate epithelial-mesenchymal transition in cancer cells mainly through the inhibition of PI3K/AKT signalling axis

Epithelial-mesenchymal transition (EMT) plays a prominent role in cancer progression and metastasis. Inhibition of EMT-associated regulators may hold a huge promise for cancer therapy. Although TGF-β signalling has a pivotal role in the induction of EMT, alterations during the EMT process are usually initiated and controlled by the cross-talk of multiple signalling pathways, and in most cases this is context-dependent. In the present study, we aimed at identifying the molecular mechanisms during the inhibition of EMT by novel anti-cancer agent myrtucommulone-A (MC-A) and thymoquinone (TQ). We used epithelial cancer cells to study the effects of MC-A and TQ on EMT. We first showed the functional inhibition of EMT by MC-A or TQ using migration assays and confirmed the EMT inhibition by analysing the expression of EMT markers with RT-PCR, immunocytochemistry and Western blotting. We evaluated the changes in intracellular dynamics by Western blotting and compared the effects of MC-A and TQ with the effects of selective inhibitors of PI3K (LY294002), ERK 1/2 (U0126) and TGF-βR (SB431542). We demonstrate that both MC-A and TQ treatment negatively regulate the EMT process through modulation of signalling pathways in cancer cells. MC-A and TQ treatment inhibited phosphorylation of multiple proteins in a context-dependent manner. Novel anti-cancer agent MC-A and TQ regulate distinct signalling pathways for the repression of EMT which emphasises the significance of combinational therapies in cancer treatment. MC-A and TQ could be considered as candidate molecules for combinational therapies with their ability to interfere signalling pathways regulating cancer cell behaviour.

Thymoquinone Modulates Blood Coagulation in Vitro via Its Effects on Inflammatory and Coagulation Pathways

Thymoquinone (THQ) is a major component of black seeds. Given that both THQ and black seeds exhibit anti-cancer and anti-inflammatory activities, we hypothesized that THQ will affect cancer-associated thrombosis (CAT), which is primarily triggered by tissue factor (TF) and inflammation. The effect of both black seed-extracted and purchased (“pure”) THQ on normal blood coagulation was tested with in vitro thromboelastography (TEG) and activated partial thromboplastin time (aPTT) coagulation assays. The effect of pure THQ on CAT was tested with aPTT assay using pancreatic cancer cell lines that are either positive or negative for TF, and with TEG assay using lipopolysaccharide as an inflammatory trigger. Additionally, the direct effect of THQ on the inactivation of factors IIa and Xa was assessed. Since TNF-α facilitates crosstalk between inflammation and thrombosis by triggering the NF-κB pathway, we tested THQ’s ability to interfere with this communication with a luciferase assay. Both extracted and pure THQ had minimal effects on normal blood coagulation. Pure THQ reversed CAT initiated by both TF and inflammation to basal levels (p < 0.001). Mechanistically, while THQ had minimal to no effect on factor IIa and Xa inactivation, it strongly reduced the effects of TNF-α on NF-κB elements (p < 0.001). THQ has a minimal effect on basal coagulation and can reverse CAT in vitro, possibly by interfering with the crosstalk between inflammation and coagulation. This study suggests the utility of THQ as a preventative anticoagulant and/or as a supplement to existing chemotherapies and anticoagulant therapies.

Growth inhibition of human gastric adenocarcinoma cells in vitro by STO-609 is independent of calcium/calmodulin-dependent protein kinase kinase-beta and adenosine monophosphate-activated protein kinase

Adenosine monophosphate (AMP)-activated protein kinase is a recently identified downstream target of calcium/calmodulin-dependent protein kinase kinase-beta, and is involved in the regulation of cell metabolism and cell proliferation. STO-609 is a selective antagonist of calcium/calmodulin-dependent protein kinase kinase-beta. In the present study, we found that STO-609 suppressed AMP-activated protein kinase activity, reduced expression of Akt and ERK, and increased cell apoptosis in SNU-1 and N87 cells but not normal gastric epithelial cells (CCL-241). Interestingly, we found such effects of STO-609 on gastric cancer cells were not affected after the knock-down of CaMKK-β and AMPK. In conclusion, STO-609 is an effective cytotoxic agent for gastric adenocarcinoma in vivo.

Antiproliferative and proapoptotic effects of topotecan in combination with thymoquinone on acute myelogenous leukemia

BACKGROUND

Topotecan has shown promising antineoplastic activity in solid tumors and acute leukemia. Because of the primary dose-limiting toxicity of topotecan, it is necessary to identify other agents that can work synergistically with topotecan, potentially increasing its efficacy while limiting its toxicity. Many studies showed synergism in combination of topotecan with gemcitabine and bortezomib. Other studies report the increase in growth inhibition of gemcitabine or oxaliplatin when cells were preexposed to naturally occurring drugs such as thymoquinone. The aim of this project was to study the mode of action of topotecan along with thymoquinone, on survival and apoptosis pathways in acute myelogenous leukemia (AML) cell lines, and to investigate the potential synergistic effect of thymoquinone on topotecan.

MATERIALS AND METHODS

U937 cells were incubated with different topotecan and thymoquinone concentrations for 24 and 48 hours, separately and in combination. Cell proliferation was determined using WST-1 (Roche) reagent. The effect of the compounds on protein expression of Bax, Bcl2, p53, caspase-9, -8, and -3 was determined using Western blot analysis. Cell cycle analysis was performed in addition to annexin/propidium iodide staining.

RESULTS

Thymoquinone and topotecan exhibited antiproliferative effects on U937 cells when applied separately. In combination, the reduction in proliferation was extremely significant with a major increase in the expression levels of Bax/Bcl2, p53, and caspase-3 and -9. Preexposure with thymoquinone resulted in an increase in cell growth inhibition compared with topotecan treatment.

CONCLUSION

Thymoquinone, when combined with topotecan in noncytotoxic doses, produced synergistic antiproliferative and proapoptotic effects in AML cells. Preexposure to thymoquinone seems to be more effective than simultaneous application with topotecan.

Dietary phytochemicals alter epigenetic events and signaling pathways for inhibition of metastasis cascade: phytoblockers of metastasis cascade

Cancer metastasis is a multistep process in which a cancer cell spreads from the site of the primary lesion, passes through the circulatory system, and establishes a secondary tumor at a new nonadjacent organ or part. Inhibition of cancer progression by dietary phytochemicals (DPs) offers significant promise for reducing the incidence and mortality of cancer. Consumption of DPs in the diet has been linked to a decrease in the rate of metastatic cancer in a number of preclinical animal models and human epidemiological studies. DPs have been reported to modulate the numerous biological events including epigenetic events (noncoding micro-RNAs, histone modification, and DNA methylation) and multiple signaling transduction pathways (Wnt/β-catenin, Notch, Sonic hedgehog, COX-2, EGFR, MAPK-ERK, JAK-STAT, Akt/PI3K/mTOR, NF-κB, AP-1, etc.), which can play a key role in regulation of metastasis cascade. Extensive studies have also been performed to determine the molecular mechanisms underlying antimetastatic activity of DPs, with results indicating that these DPs have significant inhibitory activity at nearly every step of the metastatic cascade. DPs have anticancer effects by inducing apoptosis and by inhibiting cell growth, migration, invasion, and angiogenesis. Growing evidence has also shown that these natural agents potentiate the efficacy of chemotherapy and radiotherapy through the regulation of multiple signaling pathways. In this review, we discuss the variety of molecular mechanisms by which DPs regulate metastatic cascade and highlight the potentials of these DPs as promising therapeutic inhibitors of cancer.

Thymoquinone prevents RANKL-induced osteoclastogenesis activation and osteolysis in an in vivo model of inflammation by suppressing NF-KB and MAPK Signalling

Osteoclasts are multinuclear giant cells responsible for bone resorption in inflammatory bone diseases such as osteoporosis, rheumatoid arthritis and periodontitis. Because of deleterious side effects with currently available drugs the search continues for novel effective and safe therapies. Thymoquinone (TQ), the major bioactive component of Nigella sativa has been investigated for its anti-inflammatory, antioxidant and anticancer activities. However, its effects in osteoclastogenesis have not been reported. In the present study we show for the first time that TQ inhibits nuclear factor-KB ligand (RANKL) induced osteoclastogenesis in RAW 264.7 and primary bone marrow derived macrophages (BMMs) cells. RANKL induced osteoclastogenesis is associated with increased expression of multiple transcription factors via activation of NF-KB, MAPKs signalling and reactive oxygen species (ROS). Mechanistically TQ blocked the RANKL induced NF-KB activation by attenuating the phosphorylation of IkB kinase (IKKα/β). Interestingly, in RAW 264.7 cells TQ inhibited the RANKL induced phosphorylation of MAPKs and mRNA expression of osteoclastic specific genes such as TRAP, DC-STAMP, NFATc1 and c-Fos. In addition, TQ also decreased the RANKL stimulated ROS generation in macropahges (RAW 264.7) and H2O2 induced ROS generation in osteoblasts (MC-3T3-E1). Consistent with in vitro results, TQ inhibited lipopolysaccharide (LPS) induced bone resorption by suppressing the osteoclastogenesis. Indeed, micro-CT analysis showed that bone mineral density (BMD) and bone architecture parameters were positively modulated by TQ. Taken together our data demonstrate that TQ has antiosteoclastogenic effect by inhibiting inflammation induced activation of MAPKs, NF-KB and ROS generation followed by suppressing the gene expression of c-Fos and NFATc1 in osteoclast precursors.

Chemopreventive and therapeutic potentials of thymoquinone in HepG2 cells: mechanistic perspectives

Liver cancer is the fifth commonest malignancy worldwide and the third leading cause of death. Identifying novel curative and preventive therapy may improve its prognosis. In this study, thymoquinone (TQ), the most active biological ingredient of Nigella sativa Linn, was investigated for its antitumor activity. Mechanistic perspectives underlying this antitumor activity were explored by testing its effect on cell cycle, apoptosis, and angiogenesis. In addition, the chemopreventive effect of TQ was carried out by measuring its effect on phase I CYP1A1 and phase II glutathione S-transferase (GST) drug-metabolizing enzymes. The results of the present study revealed the effectiveness of TQ as an antitumor agent against different types of cancer including brain, colon, cervix and liver at both a time- and concentration-dependent manner. In HepG2 cells, it induced G2/M phase cell cycle arrest and a concentration-dependent increase in the percentage of apoptotic cells with an increase in the ratio of Bax/BCL-2. Moreover, the expression of mRNA and protein level of vascular endothelial growth factor decreased as the concentration of TQ increased. Our data showed a significant inhibition of induced phase I CYP1A1 enzyme, and elevation in the content of glutathione and activity of phase II enzyme GST, in HepG2 cells. Our results provide support for the beneficial use of TQ as a therapeutic and chemopreventive agent against liver cancer.

Thymoquinone induces caspase-independent, autophagic cell death in CPT-11-resistant lovo colon cancer via mitochondrial dysfunction and activation of JNK and p38

Chemotherapy causes unwanted side effects and chemoresistance, limiting its effectiveness. Therefore, phytochemicals are now used as alternative treatments. Thymoquinone (TQ) is used to treat different cancers, including colon cancer. The irinotecan-resistant (CPT-11-R) LoVo colon cancer cell line was previously constructed by stepwise CPT-11 challenges to untreated parental LoVo cells. TQ dose-dependently increased the total cell death index and activated apoptosis at 2 μM, which then diminished at increasing doses. The possibility of autophagic cell death was then investigated. TQ caused mitochondrial outer membrane permeability (MOMP) and activated autophagic cell death. JNK and p38 inhibitors (SP600125 and SB203580, respectively) reversed TQ autophagic cell death. TQ was also found to activate apoptosis before autophagy, and the direction of cell death was switched toward autophagic cell death at initiation of autophagosome formation. Therefore, TQ resulted in caspase-independent, autophagic cell death via MOMP and activation of JNK and p38 in CPT-11-R LoVo colon cancer cells.

Thymoquinone restores radiation-induced TGF-β expression and abrogates EMT in chemoradiotherapy of breast cancer cells

Radiotherapy remains a prime approach to adjuvant therapies in patients with early and advanced breast cancer. In spite of therapeutic success, metastatic progression in patients undergoing therapy, limits its application. However, effective therapeutic strategies to understand the cellular and molecular machinery in inhibiting radiation-induced metastatic progression, which is poorly understood so far, need to be strengthened. Ionizing radiation was known to prompt cancer cell's metastatic ability by eliciting Transforming Growth Factor-beta (TGF-β), a key regulator in epithelial-mesenchymal transdifferentiation and radio-resistance. In this viewpoint, we employed thymoquinone as a radiosensitizer to investigate its migration and invasion reversal abilities in irradiated breast cancer cell lines by assessing their respective attributes. The role of metastasis regulatory molecules like TGF-β, E-cadherin, and integrin αV and its downstream molecules were determined using RT-PCR, western blotting, immunofluorescence, and extracellular TGF-β levels affirmed through ELISA assays. These studies affirmed the TGF-β restoring ability of thymoquinone in radiation-driven migration and invasion. Also, results demonstrated that the epithelial markers E-cadherin and cytokeratin 19 were downregulated whereas mesenchymal markers like integrin αV, MMP9, and MMP2 were upregulated by irradiation treatment; however thymoquinone pre-sensitization has reverted the expression of these proteins back to control proteins expression. Here, paclitaxel was chosen as an apoptosis inducer in TGF-β restored cells and confirmed its cytotoxic effects in radiation alone and thymoquinone sensitized irradiated cells. We conclude that this therapeutic modality is effective in preventing radiation-induced epithelial-mesenchymal transdifferentiation and concomitant induction of apoptosis in breast cancer.

Inhibition of Angiogenesis and Nitric Oxide Synthase (NOS), by Embelin & Vilangin Using in vitro, in vivo & in Silico Studies

PURPOSE

In recent year's anti-angiogenesis agents have been recognized as effective drugs for the treatment of solid tumors, this prompted us to conduct the present study.

METHODS

The anti-angiogenic activity of dimeric form of embelin (vilangin) was evaluated using endothelial cell (in vitro) and chorioallantoic membrane (CAM) egg yolk angiogenesis model (in vivo) and in addition the docking behaviour of human nitric oxide synthases (NOS) with four different ligands was evaluated along with their putative binding sites using Discovery Studio Version 3.1 (in silico) compared with the parent compound (embelin).

RESULTS

Vilangin exhibits 50% cytotoxic at 92 ± 1 µg/ml concentration level with reference to ECV 304 endothelial cells. Both vilangin and embelin, showed inhibitory effects on wound healing, single cell migration, nitric oxide production, and endothelial ring formation at 0.1 and 1.0 µg/ml concentration level. Similarly, CAM assay also showed inhibitory effect of vilangin and embelin with respect their reduction in length, size and junctions of blood capillaries compared to untreated egg yolk. Docking studies and binding free energy calculations revealed that vilangin has maximum interaction energy (-74.6 kcal/mol) as compared to the other investigated ligands.

CONCLUSION

The results suggest that both vilangin and embelin attenuates angiogenesis in similar manner.

Cardio-protective and anti-cancer therapeutic potential of Nigella sativa

Nigella sativa is the miraculous plant having a lot of nutritional and medicinal benefits, and attracts large number of nutrition and pharmacological researchers. N. sativa seed composition shows that it is the blessing of nature and it contains and many bioactive compounds like thymoquinone, α-hederin, alkaloids, flavonoids, antioxidants, fatty acids many other compounds that have positive effects on curing of different diseases. Several medicinal properties of N. sativa like its anti-cancer, anti-inflammatory, anti-diabetic, antioxidant activities and many others are well acknowledged. However, this article focuses on activity of N. sativa against cardiovascular diseases and cancer. For gathering required data the authors went through vast number of articles using search engines like Science direct, ELSEVIER, Pub Med, Willey on Line Library and Google scholar and the findings were classified on the basis of relevance of the topic and were reviewed in the article. N. sativa is rich source of different biologically active compounds and is found effective in controlling number of cardiovascular diseases and various cancers both in vivo and in vitro studies.

Elucidation of molecular targets of bioactive principles of black cumin relevant to its anti-tumour functionality - An Insilico target fishing approach

Black cumin (Nigella sativa) is a spice having medicinal properties with pungent and bitter odour. It is used since thousands of years to treat various ailments, including cancer mainly in South Asia and Middle Eastern regions. Substantial evidence in multiple research studies emphasizes about the therapeutic importance of bioactive principles of N. sativa in cancer bioassays; however, the exact mechanism of their anti-tumour action is still to be fully comprehended. The current study makes an attempt in this direction by exploiting the advancements in the Insilico reverse screening technology. In this study, three different Insilico Reverse Screening approaches have been employed for identifying the putative molecular targets of the bioactive principles in Black cumin (thymoquinone, alpha-hederin, dithymoquinone and thymohydroquinone) relevant to its anti-tumour functionality. The identified set of putative targets is further compared with the existing set of experimentally validated targets, so as to estimate the performance of insilico platforms. Subsequently, molecular docking simulations studies were performed to elucidate the molecular interactions between the bioactive compounds & their respective identified targets. The molecular interactions of one such target identified i.e. VEGF2 along with thymoquinone depicted one H-bond formed at the catalytic site. The molecular targets identified in this study need further confirmatory tests on cancer bioassays, in order to justify the research findings from Insilico platforms. This study has brought to light the effectiveness of usage of Insilico Reverse Screening protocols to characterise the un-identified target-ome of poly pharmacological bioactive agents in spices.

Interaction of human telomeric G-quadruplex DNA with thymoquinone: a possible mechanism for thymoquinone anticancer effect

BACKGROUND

Thymoquinone (TQ) has been documented to possess chemo-preventive and chemotherapeutic antitumor effects. Studies reported that TQ inhibits the growth of cancer cells in animal models, culture and xenografted tumors. Molecular mechanisms underlying these anticancer effects were attributed to inductions of cell cycle arrest, apoptosis, oxidative damage of cellular macromolecules, blockade of tumor angiogenesis and inhibitions in migration, invasion and metastasis of cancer cells. On the other hand, human telomere DNA plays a role in regulating genes' transcriptions. It folds up into G-quadruplex structures that inhibit telomerase enzyme over-expressed in cancerous cells. Molecules that selectively stabilize G-quadruplex are potential anticancer agents. Therefore, this work aimed to explore the interaction of TQ with G-quadruplex DNA as a possible underlying mechanism for the anticancer effect of TQ.

METHODS

Interactions of TQ with telomeric G-quadruplex (5'-AGGG(TTAGGG)3-3') and duplex DNAs were studied using UV-vis, fluorescence, circular dichroism, liquid and solid NMR (1H and 13C), melting temperature and docking simulation.

RESULTS

Changes in UV-vis, CD, fluorescence, 1H NMR and 13C NMR, spectra as well as melting temperatures and docking simulations provided evidences for TQ's interactions with G-quadruplex. TQ was found to interact with G-quadruplex on two binding sites adjacent to the TTA loop with binding constants 1.80×10(5) and 1.12×10(7) M(-1). Melting temperatures indicated that TQ stabilized G-quadruplex by 5.6 °C and destabilized ct-DNA by 5.1 °C. Selectivity experiment indicated that TQ is preferentially binding to G-quadruplex over duplex with selectivity coefficients of 2.80-3.33×10(-3). Results suggested an intercalation binding mode based on π-π stacking.

CONCLUSION

Our results propose that TQ can possibly act as a G-quadruplex DNA stabilizer and subsequently contribute to the inhibition of telomerase enzyme and cancer's proliferation.

GENERAL SIGNIFICANCE

Our results represent a change in the paradigms reported for structural features of G-quadruplex's stabilizers and anticancer mechanisms of TQ.

Pseudogene CYP4Z2P 3'UTR promotes angiogenesis in breast cancer

Pseudogenes have long been marked as "false" genes, which are similar with real genes but have no apparent function. The 3'UTR is well-known to regulate gene expression post-transcriptionally. Our recent evidence, however, indicates novel functional roles of pseudogene CYP4Z2P 3'UTR (Z2P-UTR). We found that ectopic expression of Z2P-UTR in breast cancer cells significantly increased the expression of VEGF-A without affecting cell proliferation in vitro. Meanwhile, conditioned medium (CM) from Z2P-UTR overexpression cells enhanced proliferation, migration and tube formation of HUVEC, and promoted angiogenesis in ex vivo models. Also, CM increased the expression of VEGFR2 in HUVEC. Our data suggest that Z2P-UTR can promote breast cancer angiogenesis partly via paracrine pathway of VEGF-A/VEGFR2.

Thymoquinone-induced conformational changes of PAK1 interrupt prosurvival MEK-ERK signaling in colorectal cancer

Background

Thymoquinone (TQ) was shown to reduce tumor growth in several cancer models both in vitro and in vivo. So far only a few targets of TQ, including protein kinases have been identified. Considering that kinases are promising candidates for targeted anticancer therapy, we studied the complex kinase network regulated by TQ.

Methods

Novel kinase targets influenced by TQ were revealed by in silico analysis of peptide array data obtained from TQ-treated HCT116wt cells. Western blotting and kinase activity assays were used to determine changes in kinase expression patterns in colorectal cancer cells (HCT116wt, DLD-1, HT29). To study the viability/apoptotic effects of combining the PAK1 inhibitor IPA-3 and TQ, crystal violet assay and AnnexinV/PI staining were employed. Interactions between PAK1 and ERK1/2 were investigated by co-immunoprecipitation and modeled by docking studies. Transfection with different PAK1 mutants unraveled the role of TQ-induced changes in PAK1 phosphorylation and TQ´s effects on PAK1 scaffold function.

Results

Of the 104 proteins identified, 50 were upregulated ≥2 fold by TQ and included molecules in the AKT-MEK-ERK1/2 pathway. Oncogenic PAK1 emerged as an interesting TQ target. Time-dependent changes in two PAK1 phosphorylation sites generated a specific kinase profile with early increase in pPAK^Thr212 followed by late increase in pPAK^Thr423. TQ induced an increase of pERK1/2 and triggered the early formation of an ERK1/2-PAK1 complex. Modeling confirmed that TQ binds in the vicinity of Thr212 accompanied by conformational changes in ERK2-PAK1 binding. Transfecting the cells with the non-phosphorylatable mutant T212A revealed an increase of pPAK^Thr423 and enhanced apoptosis. Likewise, an increase in apoptosis was observed in cells transfected with both the kinase-dead K299R mutant and PAK1 siRNA. Using structural modeling we suggest that TQ interferes also with the kinase domain consequently disturbing its interaction with pPAK^Thr423, finally inhibiting MEK-ERK1/2 signaling and disrupting its prosurvival function. pERK1/2 loss was also validated in vivo.

Conclusions

Our study shows for the first time that the small molecule TQ directly binds to PAK1 changing its conformation and scaffold function. Because TQ affects the central RAF/MEK/ERK1/2 pathway, the combination of TQ with targeted therapies is worth considering for future anticancer treatments.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-13-201) contains supplementary material, which is available to authorized users.

Crucial role for early growth response-1 in the transcriptional regulation of miR-20b in breast cancer

Transcriptional regulation of miRNAs that control the pathogenesis of breast cancer remains largely unknown. Here, we showed that ionizing radiation, a known breast carcinogen, triggered the differential expression of miR-20b in mammary tissues. We identified several GC-rich consensus binding motifs for the zinc finger transcription factor early growth response-1 (EGR1) in miR-20b promoter. miR-20b was upregulated by IR and its upregulation correlated with EGR1 expression in the breast cancer cell line HCC1806. Therefore, we used HCC1806 cells as a model system to explore the role of EGR1 in miR-20b transcription. siRNA knockdown of EGR1 attenuated miR-20b expression. Luciferase assays showed that whereas EGR1 stimulated luciferase activity driven by the wild-type miR-20b promoter, this induction was abolished in the mutant miR-20 promoter construct. We noted significant enrichment of EGR1 at miR-20b promoter in HCC1806 cells compared with normal human mammary epithelial cells. Suppression of miR-20b significantly inhibited HCC1806 cell proliferation and migration, and led to G 0/G 1 and S phase arrest. In vitro RNA-pull down assays indicated that miR-20b targets numerous tumor suppressors, including PTEN and BRCA1, which were downregulated in HCC1806. Conversely, suppression of miR-20b increased PTEN and BRCA1 levels. Moreover, immunohistochemical and FISH analyses showed that the miR-20b expression correlated significantly with EGR1 levels in breast cancer tissues. Our findings thus demonstrate for the first time that EGR1 is a key player in the transcriptional control of miR-20b, and miR-20b may in turn function as an oncogene by contributing to breast tumorigenesis via tumor suppressor targeting.