Thymoquinone (TQ) is the primary bioactive component of Nigella sativa Linn seed oil and used as anti-inflammatory, anti-oxidant, and anti-neoplastic agent. Previous studies have shown that TQ exhibits inhibitory effects on multiple cancers. However, the detailed antineoplastic effects and its molecular mechanisms of TQ on lung cancer are not entirely elucidated yet. In the present study, we aimed to investigate the effects of TQ on cell proliferation, migration, and invasion as well as its underlying anti-metastatic mechanisms in A549 cells. Lung cancer cell line A549 cells were treated with different concentration of TQ for different period of time, and the growth-inhibitory effects of TQ was measured by MTT and cell count assays; cell cycle was determined by flow cytometry; wound healing and transwell assays were used to assess the cell migration and invasion activities; Western blot and real-time quantitative RT-PCR were used to determine the expression of proliferation and invasion associated genes as well as MAPKs pathway molecules; gelatinase activity was estimated using gelatin zymography assay. The results show that TQ played a role in inhibiting the proliferation, migration, and invasion of A549 lung cancer cells, it also inhibited the expression level of PCNA, cyclin D1, MMP2, and MMP9 mRNA and protein in a dose- and time-dependent manner especially at 10, 20, 40 Î¼mol/L concentrations. The cell cycle inhibitor P16 expression and the gelatinase activities of MMP2 and MMP9 were also inhibited by TQ dramatically. TQ reduced phosphorylation of ERK1/2; however, the proliferation and invasion inhibitory effects of TQ on A549 cells were neutralized by ERK1/2 inhibitor PD98059. In conclusion, our study confirmed that TQ could inhibit A549 cell proliferation, migration, and invasion through ERK1/2 pathway, as proposed the therapeutic potential of TQ as an anti-metastatic agent in human lung cancer treatment.

BACKGROUND:

Phytochemical compounds are emerging as a new generation of anticancer agents with limited toxicity in cancer patients. The purpose of this study was to investigate the potential effcts ofthymoquinone, caffeic acid phenylester (CAPE) and resveratrol on inflammatory markers, oxidative stress parameters, mRNA expression levels of proteins and survival of lung cancer cells in Vitro.

MATERIALS AND METHODS:

The A549 cell line was treated with benzo(a)pyrene, benzo(a)pyrene plus caffeic acid phenylester (CAPE), benzo(a)pyrene plus resveratrol (RES), and benzo(a)pyrene plusthymoquinone (TQ). Inflammatory markers, oxidative stress parameters, mRNA expression levels of apoptotic and anti-apoptotic proteins and cell viability were assessed and results were compared among study groups.

RESULTS:

TQ treatment up-regulated Bax and down-regulated Bcl2 proteins and increased the Bax/Bcl2 ratio. CAPE and TQ also up-regulated Bax expression. RES and TQ down-regulated the expression of Bcl-2. All three agents decreased the expression of cyclin D and increased the expression of p21. However, the most significant up-regulation of p21 expression was observed in TQ treated cells. CAPE, RES and TQ up-regulated TRAIL receptor 1 and 2 expression. RES and TQ down-regulated the expression of NF-kappa B and IKK1. Viability of CAPE, RES and TQ treated cells was found to be significantly decreased when compared with the control group (p=0.004).

CONCLUSIONS:

Our results revealed up-regulation of the key upstream signaling factors, which ultimately cause increase in their regulatory p53 levels affecting the induction of G2/M cell cycle arrest and apoptosis. Overall these results provide mechanistic insights for understanding the molecular basis and utility of the anti-tumor activity of TQ, RES and CAPE.

Phytochemical compounds are emerging as a new generation of anticancer agents with limited toxicity incancer patients. The purpose of this study was to investigate the potential impact of thymoquinone (TQ), the major constituent of black seed, on survival, invasion of cancer cells in vitro, and tumor growth in vivo. Exposure of cells derived from lung (LNM35), liver (HepG2), colon (HT29), melanoma (MDA-MB-435), and breast (MDA-MB-231 and MCF-7) tumors to increasing TQ concentrations resulted in a significant inhibition of viability through the inhibition of Akt phosphorylation leading to DNA damage and activation of the mitochondrial-signaling proapoptotic pathway. We provide evidence that TQ at non-toxic concentrations inhibited the invasive potential of LNM35, MDA-MB-231, and MDA-MB231-1833 cancer cells. Moreover, we demonstrate that TQ synergizes with DNA-damaging agent cisplatin to inhibit cellular viability. The anticancer activity of thymoquinone was also investigated in athymic mice inoculated with the LNM35 lung cells. Administration of TQ (10 mg/kg/i.p.) for 18 days inhibited the LNM35 tumor growth by 39% (P < 0.05). Tumor growth inhibition was associated with significant increase in the activated caspase-3. The in silico target identification suggests several potential targets of TQ mainly HDAC2 proteins and the 15-hydroxyprostaglandin dehydrogenase. In this context, we demonstrated that TQ treatment resulted in a significant inhibition of HDAC2 proteins. In view of the available experimental findings, we contend that thymoquinone and/or its analogues may have clinical potential as an anticancer agent alone or in combination with chemotherapeutic drugs such as cisplatin.

Thymoquinone is an active ingredient isolated from Nigella sativa and has been investigated for its anti-oxidant, anti-inflammatory and anticancer activities in both in vitro and in vivo models since its first extraction in 1960s. Its anti-oxidant/anti-inflammatory effect has been reported in various disease models, including encephalomyelitis, diabetes, asthma and carcinogenesis. Moreover, thymoquinone could act as a free radical and superoxide radical scavenger, as well as preserving the activity of various anti-oxidant enzymes such as catalase, glutathione peroxidase and glutathione-S-transferase. The anticancer effect(s) of thymoquinone are mediated through different modes of action, including anti-proliferation, apoptosis induction, cell cycle arrest, ROS generation and anti-metastasis/anti-angiogenesis. In addition, this quinone was found to exhibit anticancer activity through the modulation of multiple molecular targets, including p53, p73, PTEN, STAT3, PPAR-γ, activation of caspases and generation of ROS. The anti-tumor effects of thymoquinone have also been investigated in tumor xenograft mice models for colon, prostate, pancreatic and lung cancer. The combination of thymoquinone and conventional chemotherapeutic drugs could produce greater therapeutic effect as well as reduce the toxicity of the latter. In this review, we summarize the anti-oxidant/anti-inflammatory and anticancer effects of thymoquinone with a focus on its molecular targets, and its possible role in the treatment of inflammatory diseases and cancer.

Related citations

Nigella sativa has been used as traditional medicine for centuries. The crude oil and thymoquinone (TQ) extracted from its seeds and oil are effective against many diseases like cancer, cardiovascular complications, diabetes, asthma, kidney disease etc. It is effective against cancer in blood system, lung, kidney, liver, prostate, breast, cervix, skin with much safety. The molecular mechanisms behind its anticancer role is still not clearly understood, however, some studies showed that TQ has antioxidant role and improves body’s defense system, induces apoptosis and controls Akt pathway. Although the anti-cancer activity of N. sativa components was recognized thousands of years ago but proper scientific research with this important traditional medicine is a history of last 2∼3 decades. There are not so many research works done with this important traditional medicine and very few reports exist in the scientific database. In this article, we have summarized the actions of TQ and crude oil of N. sativa against different cancers with their molecular mechanisms.

BACKGROUND:

Thymoquinone (TQ) is a compound extracted from Black Caraway seeds of Nigella Sativa and is active against various cancers. Cisplatin (CDDP) is the most active chemotherapeutic agent in Lung Cancer. Here we report activity of TQ against non-small cell lung cancer (NSCLC) and small cell lung cancer(SCLC) cell lines alone and in combination with Cisplatin (CDDP).

METHODS:

For proliferation MTT assay, cell viability trypan blue assay and for apoptosis Annexin-V FITC assay were used in NCI-H460 and NCI-H146 cell lines. Inhibition of invasion by TQ was assessed using Matrigel assay and its affect on release of various cytokines was determined using RayBio Human Cytokine detection kit. Mouse xenograft model using NCI-H460 was used to determine in vivo activity of TQ and CDDP. Inhibition of LPS induced NF-kappaB expression by TQ was determined using transgenic mice expressing a luciferase reporter.

RESULTS:

TQ was able to inhibit cell proliferation, reduce cell viability and induce apoptosis. TQ at 100 microM and CDDP at 5 muM inhibited cell proliferation by nearly 90% and the combination showed synergism. TQ was able to induced apoptosis in both NCI-H460 and NCI-H146 cell lines. TQ also appears to affect the extracellular environment inhibiting invasion and reducing the production of two cytokines ENA-78 and Gro-alpha which are involved in neo-angiogenesis. Using a mouse xenograft model we were able to demonstrate that combination of TQ and CDDP was well tolerated and significantly reduced tumor volume and tumor weight without additional toxicity to the mice. In the combination arms (TQ5 mg/kg/Cis 2.5 mg/kg) tumor volume was reduced by 59% and (TQ20 mg/kg/Cis 2.5 mg/kg) by 79% as compared to control which is consistent with in vitro data. TQ down regulated NF-kappaB expression which may explain its various cellular activities and this activity may prove useful in overcoming CDDP resistance from over expression of NF-kappaB.

CONCLUSIONS:

Thus TQ and CDDP appear to be an active therapeutic combination in lung cancer.