Multi-targeted prevention of cancer by sulforaphane

Sulforaphane-Conjugated Carbon Dots: A Versatile Nanosystem for Targeted Imaging and Inhibition of EGFR-Overexpressing Cancer Cells

Because of the demand for precision medicine, the investigatation on the application of carbon-dots-based nanosystems in the field of biomedicine is attracting more and more attention. Therefore, we have built a multifunctional nanosystem based on sulforaphane-conjugated carbon dots (SFN-CDs) with thiourea skeleton and applied for EGFR-overexpressing cancer cells targeted imaging and inhibiting. The SFN-CDs are formed by grafting sulforaphane on the amino-rich yellow fluorescent carbon dots, which have excellent optical stability and can be distinguished from normal cells for targeted imaging of cancer cells. The vitro toxicity experiments demonstrated that the SFN-CDs can effectively inhibit EGFR-overexpressing cancer cell proliferation at concentrations below 100 μg mL^-1. All these results validated that SFN-CDs nanoparticles with integration of diagnostic and therapeutic functions can be used as a potential nanodurg in early stage of cancer control. Moreover, this work provides useful insight into targeted nanoparticle design in the biological nanomedicine field.

In Search of Panacea-Review of Recent Studies Concerning Nature-Derived Anticancer Agents

Cancers are one of the leading causes of deaths affecting millions of people around the world, therefore they are currently a major public health problem. The treatment of cancer is based on surgical resection, radiotherapy, chemotherapy or immunotherapy, much of which is often insufficient and cause serious, burdensome and undesirable side effects. For many years, assorted secondary metabolites derived from plants have been used as antitumor agents. Recently, researchers have discovered a large number of new natural substances which can effectively interfere with cancer cells’ metabolism. The most famous groups of these compounds are topoisomerase and mitotic inhibitors. The aim of the latest research is to characterize natural compounds found in many common foods, especially by means of their abilities to regulate cell cycle, growth and differentiation, as well as epigenetic modulation. In this paper, we focus on a review of recent discoveries regarding nature-derived anticancer agents.

Sulforaphane Attenuates Endometriosis in Rat Models Through Inhibiting PI3K/Akt Signaling Pathway

Sulforaphane exerts anti-inflammatory activity in inflammatory diseases. The endometriosis (EM) is accompanied by chronic inflammation. The present study aims to explore the therapeutic effects of sulforaphane on EM and its underlying mechanism. An EM rat model was established by transplantation of autologous fragments. The rats were intragastrically administered sulforaphane (5 mg/kg, 15 mg/kg, and 30 mg/kg) for 3 weeks. The volumes of endometriotic foci and adhesion score were calculated at the end of the experiment. Levels of interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and vascular endothelial growth factor (VEGF) were determined by enzyme-linked immunosorbent assay (ELISA). Expressions of VEGF, B-cell lymphoma/leukemia 2 (Bcl-2), Bax, cleaved caspase-3, PI3K, and Akt in endometrial tissue were determined by Western blotting. Relative expressions of PI3K and Akt were determined by quantitative polymerase chain reaction. Posttreatment of sulforaphane dose-dependently decreased the volumes of endometriotic foci and adhesion score in EM model. Additionally, posttreatment of sulforaphane inhibited levels of IL-6, IL-10, TNF-α, IFN-γ, and VEGF in peritoneal fluid and plasma. Posttreatment of sulforaphane regulated the expressions of VEGF, bcl-2, Bax, and cleaved Caspase-3 in EM model. The underlying mechanism revealed that sulforaphane attenuated EM in the rat model by inhibition of PI3K/Akt signaling pathway.

Unraveling the Potential Role of Glutathione in Multiple Forms of Cell Death in Cancer Therapy

Glutathione is the principal intracellular antioxidant buffer against oxidative stress and mainly exists in the forms of reduced glutathione (GSH) and oxidized glutathione (GSSG). The processes of glutathione synthesis, transport, utilization, and metabolism are tightly controlled to maintain intracellular glutathione homeostasis and redox balance. As for cancer cells, they exhibit a greater ROS level than normal cells in order to meet the enhanced metabolism and vicious proliferation; meanwhile, they also have to develop an increased antioxidant defense system to cope with the higher oxidant state. Growing numbers of studies have implicated that altering the glutathione antioxidant system is associated with multiple forms of programmed cell death in cancer cells. In this review, we firstly focus on glutathione homeostasis from the perspectives of glutathione synthesis, distribution, transportation, and metabolism. Then, we discuss the function of glutathione in the antioxidant process. Afterwards, we also summarize the recent advance in the understanding of the mechanism by which glutathione plays a key role in multiple forms of programmed cell death, including apoptosis, necroptosis, ferroptosis, and autophagy. Finally, we highlight the glutathione-targeting therapeutic approaches toward cancers. A comprehensive review on the glutathione homeostasis and the role of glutathione depletion in programmed cell death provide insight into the redox-based research concerning cancer therapeutics.

Moringin from Moringa Oleifera Seeds Inhibits Growth, Arrests Cell-Cycle, and Induces Apoptosis of SH-SY5Y Human Neuroblastoma Cells through the Modulation of NF-κB and Apoptotic Related Factors

In the last decades, glucosinolates (GLs), precursors of isothiocyanates (ITCs), have been studied mostly for their chemopreventive and chemotherapeutic properties. The aim of our research was to study the antiproliferative effect of 4-(α-L-rhamnopyranosyloxy) benzyl glucosinolate (glucomoringin; GMG) bioactivated by myrosinase enzyme to form the corresponding isothiocyanate 4-(α-L-rhamnopyranosyloxy) benzyl C (moringin) in SH-SY5Y human neuroblastoma cells. We found that moringin significantly reduced SH-SY5Y cell growth in a time and concentration-dependent (p < 0.05, 0.01, and 0.001 vs. ctrl, after treatment with 16.4 µM moringin for 24, 48, and 72 h, respectively) manner through a mechanism involving the activation of apoptotic machinery. In addition, it altered the normal progression of cells through the cell cycle, increasing the cell population in both G2 and S phases, as well as decreasing that in the G1 phase. Studying the drug mechanism of action, we found that moringin was able to increase the expression of p53, p21, and Bax at both the protein and transcriptional level. Moreover, exposure of SH-SY5Y cells to moringin significantly increased the gene expression of both caspase 3 and 9 and enhanced their cleavage, thereby initiating an intrinsic apoptotic cascade. Finally, moringin inhibited nuclear translocation of NF-κB. Our study demonstrates the ability of moringin to reduce the growth of SH-SY5Y cells and reveals its mechanism of action, suggesting its promising role as an anticancer drug.

1-Methoxy-3-indolylmethyl DNA adducts in six tissues, and blood protein adducts, in mice under pak choi diet: time course and persistence

We previously showed that purified 1-methoxy-3-indolylmethyl (1-MIM) glucosinolate, a secondary plant metabolite in Brassica species, is mutagenic in various in vitro systems and forms DNA and protein adducts in mouse models. In the present study, we administered 1-MIM glucosinolate in a natural matrix to mice, by feeding a diet containing pak choi powder and extract. Groups of animals were killed after 1, 2, 4 and 8 days of pak choi diet, directly or, in the case of the 8-day treatment, after 0, 8 and 16 days of recovery with pak choi-free diet. DNA adducts [N²-(1-MIM)-dG, N⁶-(1-MIM)-dA] in six tissues, as well as protein adducts [τN-(1-MIM)-His] in serum albumin (SA) and hemoglobin (Hb) were determined using UPLC-MS/MS with isotopically labeled internal standards. None of the samples from the 12 control animals under standard diet contained any 1-MIM adducts. All groups receiving pak choi diet showed DNA adducts in all six tissues (exception: lung of mice treated for a single day) as well as SA and Hb adducts. During the feeding period, all adduct levels continuously increased until day 8 (in the jejunum until day 4). During the 14-day recovery period, N²-(1-MIM)-dG in liver, kidney, lung, jejunum, cecum and colon decreased to 52, 41, 59, 11, 7 and 2%, respectively, of the peak level. The time course of N⁶-(1-MIM)-dA was similar. Immunohistochemical analyses indicated that cell turnover is a major mechanism of DNA adduct elimination in the intestine. In the same recovery period, protein adducts decreased more rapidly in SA than in Hb, to 0.7 and 37%, respectively, of the peak level, consistent with the differential turnover of these proteins. In conclusion, the pak choi diet lead to the formation of high levels of adducts in mice. Cell and protein turnover was a major mechanism of adduct elimination, at least in gut and blood.

Deciphering the Nutraceutical Potential of Raphanus sativus-A Comprehensive Overview

Raphanus sativus (Radish) belongs to the Brassicaceae family and is a widely consumed root vegetable all around the world. The nutritional and medicinal values of radishes have been proven by several researches. Extracts prepared from the aerial and underground parts of radishes have been used in the treatment of stomach disorders, urinary infections, hepatic inflammation, cardiac disorders and ulcers in folk medicine since the ancient times. The pharmaceutical potential of radishes is attributed to the presence of its beneficial secondary metabolites, such as glucosinolates, polyphenols and isothiocyanates. The present review has focused on the impact of radish extract administration under pathological complications, such as cancer, diabetes, hepatic inflammation and oxidative stress. In addition, a comprehensive view of molecular mechanism behind the regulation of molecular drug targets associated with different types of cancers and diabetes by the bioactive compounds present in the radish extracts have been discussed in detail.

Lycopene, sulforaphane, quercetin, and curcumin applied together show improved antiproliferative potential in colon cancer cells in vitro

Lycopene, sulforaphane, quercetin, and curcumin, ingredients of daily diet, show significant anticancer and chemopreventive potential; however, no data are available showing thorough evaluation of jointly used phytochemicals on cancer cell proliferation. Here, we compare anticancer potential of mentioned substances applied separately or in combination (as MIX) by measuring mitochondrial activity (MTT test), DNA synthesis (BrdU test) and lactate dehydrogenase release (LDH test) in colon epithelial (CCD841 CoTr), and colon cancer (HT-29, LS174T) cells. Additive inhibitory effect of simultaneously used phytochemicals on cancer cells proliferation has been shown. In epithelial cells, tested combination effectively inhibited mitochondrial activity, but not DNA synthesis. LDH test revealed cytotoxicity of tested mixture against cancer cells without negative effect on normal cells. Furthermore, we demonstrated that MIX enhances antiproliferative effect of common cytostatics: 5-fluorouracil and cisplatin. Presented data suggest chemopreventive potential of the proposed combination of natural substances and their usefulness as adjuvant strategy during chemotherapy. PRACTICAL APPLICATIONS: Colorectal cancer is one of the most common causes of cancer death worldwide. Since its development and progression is strongly correlated with dietary habits, healthy diet as well as supplementation with proved anticancer agents seems to be reasonable strategy of colon cancer prevention and treatment. In the present study, we have focused on four natural compounds abundantly found in daily diet i.e., lycopene, sulforaphane, quercetin, and curcumin, with well established anticancer potential. Their individual and collective impact both on normal colon epithelium cells and colon cancer cells viability, growth, and proliferation was examined. Furthermore, activity of the substances combined as MIX to influence antiproliferative potential of commonly used in colon cancer treatment cytostatics, 5-fluorouracil, and cisplatin was verified. Proposed in the study combination of phytochemicals with experimentally proven antiproliferative activity may propose an effective strategy for prevention and treatment of colon cancer.

Selected Office Based Anticancer Treatment Strategies

Over the years, the treatment of patients with cancer has varied widely as much because of recent advancements in science and medicine as the philosophies that belie their use. This paper briefly describes many of the prevailing approaches in use today with an attempt to offer some perspective of how to apply these disparate methodologies so that they may be more effectively integrated, resulting in consistently better clinical responses.

New diaryl ω-(isothiocyanato)alkylphosphonates and their mercapturic acids as potential antibacterial agents

Thirty-four novel, diaryl ω-(isothiocyanato)alkylphosphonates with chlorine atom and methoxy, dimethoxy, methylsulfanyl, or methoxycarbonyl groups at ortho, meta, or para positions of the phenyl ring, and with an unbranched alkyl chain (n = 2-6) were designed and synthesized in a one-pot reaction in 11-76% yields. All isothiocyanates thus generated were evaluated for the first time for antibacterial activity on Pseudomonas aeruginosa and Staphylococcus aureus bacterial strains, and had satisfactory antibacterial activity in most cases. The highest activity, similar to that of reference gentamicin activity against S. aureus, was seen in compounds 9 and 13 (1.5 ± 0.1 and 2.5 ± 0.2 μM, respectively), whereas for P. aeruginosa more than half of tested compounds proved to be more effective than gentamicin. Additionally, selected isothiocyanates (9, 13, 18, and 23) were transformed in 52-73% yields into mercapturic acids 42-45, which also exhibited satisfactory antibacterial effect against S. aureus strain.

Emerging role of nuclear factor erythroid 2-related factor 2 in the mechanism of action and resistance to anticancer therapies

Nuclear factor E2-related factor 2 (NRF2), a transcription factor, is a master regulator of an array of genes related to oxidative and electrophilic stress that promote and maintain redox homeostasis. NRF2 function is well studied in in vitro, animal and general physiology models. However, emerging data has uncovered novel functionality of this transcription factor in human diseases such as cancer, autism, anxiety disorders and diabetes. A key finding in these emerging roles has been its constitutive upregulation in multiple cancers promoting pro-survival phenotypes. The survivability pathways in these studies were mostly explained by classical NRF2 activation involving KEAP-1 relief and transcriptional induction of reactive oxygen species (ROS) neutralizing and cytoprotective drug-metabolizing enzymes (phase I, II, III and 0). Further, NRF2 status and activation is associated with lowered cancer therapeutic efficacy and the eventual emergence of therapeutic resistance. Interestingly, we and others have provided further evidence of direct NRF2 regulation of anticancer drug targets like receptor tyrosine kinases and DNA damage and repair proteins and kinases with implications for therapy outcome. This novel finding demonstrates a renewed role of NRF2 as a key modulatory factor informing anticancer therapeutic outcomes, which extends beyond its described classical role as a ROS regulator. This review will provide a knowledge base for these emerging roles of NRF2 in anticancer therapies involving feedback and feed forward models and will consolidate and present such findings in a systematic manner. This places NRF2 as a key determinant of action, effectiveness and resistance to anticancer therapy.

Antitumor activity of sulforaphane in mice model of skin cancer via blocking sulfatase-2

Although there are many treatment options for skin cancer, the chemotherapeutic agents for skin cancer are linked with many adverse effects as well as the development of multidrug resistance. Sulforaphane is an isothiocyanate, which is found in cruciferous vegetables. Consumption of sulforaphane-rich diet has been linked to inhibition of UV-exposed skin carcinogenesis. Therefore, the goal of this study was to determine the ability of sulforaphane to reduce skin cancer in mice through inhibition of sulfatase-2 enzyme. Epicutaneous application of 7,12-dimethylbenz (a) anthracene was performed on the shaved dorsal skin of mice followed by croton oil. Sulforaphane (9 μmol/mouse/day) was administered to mice orally. Skin was removed from the dorsal area for assessment of sulfatase-2, glypican-3, heparan sulphate proteoglycans (HSPGs), nuclear factor (NF)κB, nuclear factor E2-related factor 2 (Nrf2), tumor necrosis factor (TNF)-α, IL-1β and caspase-3. In addition, skin sections were stained with haematoxylin/eosin, Mallory and cytokeratin immunostaining. We found that, sulforaphane blocked sulfatase-2 activity, leading to significant elevation in HSPGs as well as significant reduction in glypican-3. In addition, sulforaphane significantly activated Nrf2 and reduced both the gene and protein expression of NFκB, TNF-α, IL-1β and caspase-3. In parallel, stained sections obtained from skin cancer mice treated with sulforaphane showed significant reduction in hyperkeratosis, acanthosis and epithelial dysplasia. The collective results indicate that sulforaphane suppresses skin cancer via blocking sulfatase-2 with subsequent elevation in HSPGs and reduction in glypican-3. Moreover, sulforaphane attenuated skin cancer-induced activation of inflammatory and apoptotic pathways.

Personalized Nutrition in Disrupting Cancer - Proceedings From the 2017 American College of Nutrition Annual Meeting

Cancer is a major public health problem and is the second leading cause of death in the United States and worldwide; nearly one in six deaths are attributable to cancer. Approximately 20% of all cancers diagnosed in the United States are attributable to unhealthy diet, excessive alcohol consumption, physical inactivity, and body fatness. Individual cancers are distinct disease states that are multifactorial in their causation, making them exceedingly cumbersome to study from a nutrition standpoint. Genetic influences are a major piece of the puzzle and personalized nutrition is likely to be most effective in disrupting cancer during all stages. Increasing evidence shows that after a cancer diagnosis, continuing standard dietary recommendations may not be appropriate. This is because powerful dietary interventions such as short-term fasting and carbohydrate restriction can disrupt tumor metabolism, synergizing with standard therapies such as radiation and drug therapy to improve efficacy and ultimately, cancer survival. The importance of identifying dietary interventions cannot be overstated, and the American College of Nutrition's commitment to advancing knowledge and research is evidenced by dedication of the 2017 ACN Annual Meeting to "Disrupting Cancer: The Role of Personalized Nutrition" and this resulting proceedings manuscript, which summarizes the meeting's findings.

Sulforaphane-decorated gold nanoparticle for anti-cancer activity: in vitro and in vivo studies

This study aims to develop sulforaphane-loaded gold nanoparticles (SFN-GNPs) as a potential nanomedicine against the solid tumors. Citrate-mediated electrolysis optimized by four-factor three-level Box-Behnken experimental design was used to get nanoparticles of size <200 nm. The formulation was characterized and evaluated for cytotoxicity B16-F10, MCF-7, SW-620 and Caco-2 cell line. Single dose oral pharmacokinetics, gamma scintigraphy-based bio-distribution and tumor regression studies were conducted to evaluate the in vivo performance. Optimized SFN-GNPs showed spherical morphology with a particle size of 147.23 ± 5.321 nm, the zeta potential of -12.7 ± 1.73 mV, entrapment efficiency of 83.17 ± 3.14% and percentage drug loading of 37.26 ± 2.33%. With SFN-GNPs, both SFN (75.99 ± 2.36%) and gold (58.11 ± 2.48%) were able to permeate through the intestinal wall in 48 h. SFN-GNPs were able to bring LC₅₀ of <100 µg/ml in all the cytotoxicity assays, more than 5-fold increase in AUC_0-t, enhanced retention at tumor site as well as significant pre-induction tumor growth inhibition and post-induction tumor reduction as compared to plain SFN solution.

Sulforaphane as anticancer agent: A double-edged sword? Tricky balance between effects on tumor cells and immune cells

Sulforaphane (SFN) is a naturally occurring isothiocyanate derived from cruciferous vegetables such as broccoli. It has been reported to inhibit the growth of a variety of cancers, such as breast, prostate, colon, skin, lung, gastric or bladder cancer. SFN is supposed to act primarily as an antioxidant due to the activation of the Nrf2-Keap1 signaling pathway. This enhances the activity of phase II detoxifying enzymes and the trapping of free radicals. Finally, SFN induces cell cycle arrest or apoptosis of tumor cells. Here, we discuss effects of SFN on the immune defense system. In contrast to the situation in tumor cells, SFN acts pro-oxidatively in primary human T cells. It increases intracellular ROS levels and decreases GSH, resulting in inhibition of T cell activation and T cell effector functions. Regarding the use of SFN as an "anticancer agent" we conclude that SFN could act as a double-edged sword. On the one hand it reduces carcinogenesis, on the other hand it blocks the T cell-mediated immune response, the latter being important for immune surveillance of tumors. Thus, SFN could also interfere with the successful application of immunotherapy by immune checkpoint inhibitors (e.g. CTLA-4 antibodies and PD-1/PD-L1 antibodies) or CAR T cells. Therefore, a combination of SFN with T cell-mediated cancer immunotherapies does not seem advisable.

In Vitro Evaluation of Sulforaphane and a Natural Analog as Potent Inducers of 5-Fluorouracil Anticancer Activity

Isothiocyanates (R-NCS) are sulphur-containing phytochemicals. The main source are plants of the Brassicaceae family. The best known plant-derived isothiocyanate is sulforaphane that has exhibited anticancer activity in both in vivo and in vitro studies. Recent attempts to expand their use in cancer therapy involve combining them with standard chemotherapeutics in order to increase their therapeutic efficacy. The aim of this paper is to determine the impact of sulforaphane and its natural analog alyssin on the anticancer activity of the well-known anticancer drug 5-fluorouracil. The type of drug-drug interactions was determined in prostate and colon cancer cell lines. Confocal microscopy, western blot and flow cytometry methods were employed to determine the mechanism of cytotoxic and cytostatic action of the combinations. The study revealed that additive or synergistic interactions were observed between 5-fluorouracil and both isothiocyanates, which enhanced the anticancer activity of 5-fluorouracil, particularly in colon cancer cell lines. An increased cytostatic effect was observed in case of alyssin while for sulforaphane the synergistic interaction with 5-fluorouracil involved an intensification of apoptotic cell death.

Sulforaphane regulates apoptosis- and proliferation‑related signaling pathways and synergizes with cisplatin to suppress human ovarian cancer

Ovarian cancer is currently the most life‑threatening type of gynecological malignancy with limited treatment options. Therefore, improved targeted therapies are required to combat ovarian cancer across the world. Sulforaphane is found in raw cruciferous vegetables. The chemotherapeutic and anti‑carcinogenic properties of sulforaphane have been demonstrated, however, the underlying mechanisms remain to be fully elucidated, particularly in ovarian cancer. In the present study, the possibility of repurposing sulforaphane as an anti‑ovarian cancer agent was examined. Cell viability and colony formation assay were used to test the anticancer efficiency of sulforaphane. Then wound healing assay, migration assay, cell cycle and apoptosis assays were used to detect how the drug worked on the cells. The mechanism of sulforaphane was investigated by western blot analysis. It was found that sulforaphane effectively suppressed the progression of human ovarian cancer cell proliferation, migration and cell cycle, and promoted apoptosis. Sulforaphane inhibited multiple cancer‑associated signaling pathways, including B‑cell lymphoma 2 (Bcl‑2), Bcl‑2‑associated X protein, cytochrome c, Caspase‑3, phosphorylated AKT, phosphorylated nuclear factor‑κB, P53, P27, Cyclin‑D1 and cMyc, and reduced the expression levels of human epidermal growth factor receptor 2 in human ovarian cancer cells. Sulforaphane synergized with cisplatin to suppress the cancer cell proliferation and enhance ovarian cancer cell apoptosis. Xenograft experiments in vivo confirmed that sulforaphane effectively suppressed tumor growth by inhibiting ovarian cancer cell proliferation through targeting tumor‑related signals. The results indicated that sulforaphane may be repurposed as an effective anti‑ovarian cancer agent, with further preclinical or clinical investigations required.

Alleviating the progression of acute myeloid leukemia (AML) by sulforaphane through controlling miR-155 levels

Acute myeloid leukemia (AML) has the highest rate of mortality among the leukemias. Disruption in miRNAs level is involved in the pathogenesis of the disease. The miR-155 has a role in primary differentiation of myeloid progenitor. Meanwhile, there is little knowledge about the effects of sulforaphane against leukemia. The present study tried to evaluate pathologic effect of miR-155 in patients in various subgroups of AML, and then pioneered in assessing miR-155 levels by the effect of sulforaphane in different AML cell lines. The miR-155 level was significantly higher in patients with AML compared to the controls. Interestingly, the increase in miR-155 was converged with raising the subtype of AML (from M1 to M5). The miR-155 levels increased by 1.2 times in patients with M1, but this increase reached 2.5 times in the patients in the M5 subgroup. Sulforaphane reduced the number of live cells and increased the mortality rate of AML cells particularly by induction of apoptosis. However, the anti-proliferative effect of this agent was more dominant and could dose-dependently lessen miR-155 levels in myeloid leukemia cells. More or less, about 80% reduction in miR-155 expression was almost observed after 48 h treatment with 60 µM sulforaphane in all four studied cell lines. The obtained results indicated that miR-155 might function as an oncomir in AML and can potentially be considered as a prognosis biomarker for AML. The anti-cancer effects of sulforaphane can be correlated with reduction of miR-155 levels. These findings suggested that sulforaphane could induce more differentiation in myeloid progenitor cells through controlling the miR-155, thereby mitigating the progress of AML.

Cruciferous Vegetables, Isothiocyanates, and Bladder Cancer Prevention

Bladder cancer is a significant health burden due to its high prevalence, risk of mortality, morbidity, and high cost of medical care. Epidemiologic evidence suggests that diets rich in cruciferous vegetables, particularly broccoli, are associated with lower bladder cancer risk. Phytochemicals in cruciferous vegetables, such as glucosinolates, which are enzymatically hydrolyzed to bioactive isothiocyanates, are possible mediators of an anticancer effect. In vitro studies have shown inhibition of bladder cancer cell lines, cell cycle arrest, and induction of apoptosis by these isothiocyanates, in particular sulforaphane and erucin. Although not yet completely understood, many mechanisms of anticancer activity at the steps of cancer initiation, promotion, and progression have been attributed to these isothiocyanates. They target multiple pathways including the adaptive stress response, phase I/II enzyme modulation, pro-growth, pro-survival, pro-inflammatory signaling, angiogenesis, and even epigenetic modulation. Multiple in vivo studies have shown the bioavailability of isothiocyanates and their antitumoral effects. Although human studies are limited, they support oral bioavailability with reasonable plasma and urine concentrations achieved. Overall, both cell and animal studies support a potential role for isothiocyanates in bladder cancer prevention and treatment. Future studies are necessary to examine clinically relevant outcomes and define guidelines on ameliorating the bladder cancer burden.

Nontoxic Glucomoringin-Isothiocyanate (GMG-ITC) Rich Soluble Extract Induces Apoptosis and Inhibits Proliferation of Human Prostate Adenocarcinoma Cells (PC-3)

The incidence of prostate cancer malignancy along with other cancer types is increasing worldwide, resulting in high mortality rate due to lack of effective medications. Moringa oleifera has been used for the treatment of communicable and non-communicable ailments across tropical countries, yet, little has been documented regarding its effect on prostate cancer. We evaluated the acute toxicity and apoptosis inducing effect of glucomoringin-isothiocyanate rich soluble extracts (GMG-ITC-RSE) from M. oleifera in vivo and in vitro, respectively. Glucomoringin was isolated, identified, and characterized using fundamental analytical chemistry tools where Sprague-Dawley (SD) rats, murine fibroblast (3T3), and human prostate adenocarcinoma cells (PC-3) were used for acute toxicity and bioassays experiments. GMG-ITC-RSE did not instigate adverse toxic reactions to the animals even at high doses (2000 mg/kg body weight) and affected none of the vital organs in the rats. The extract exhibited high levels of safety in 3T3 cells, where more than 90% of the cells appeared viable when treated with the extract in a time-dependent manner even at high dose (250 µg/mL). GMG-ITC-RSE significantly triggered morphological aberrations distinctive to apoptosis observed under microscope. These findings obviously revealed the putative safety of GMG-ITC-RSE in vivo and in vitro, in addition to its anti-proliferative effect on PC-3 cells.

Benzyl isothiocyanate (BITC) triggers mitochondria-mediated apoptotic machinery in human cisplatin-resistant oral cancer CAR cells

Benzyl isothiocyanate (BITC), a component of dietary food, possesses a powerful anticancer activity. Previous studies have shown that BITC produces a large number of intracellular reactive oxygen species (ROS) and increases intracellular Ca²⁺ release from endoplasmic reticulum (ER), leading to the activation of the apoptotic mechanism in tumor cells. However, there is not much known regarding the inhibitory effect of BITC on cisplatin-resistant oral cancer cells. The purpose of this study was to examine the anticancer effect and molecular mechanism of BITC on human cisplatin-resistant oral cancer CAR cells. Our results demonstrated that BITC significantly reduced cell viability of CAR cells in a concentration- and time-dependent manner. BITC was found to cause apoptotic cell shrinkage and DNA fragmentation by morphologic observation and TUNEL/DAPI staining. Pretreatment of cells with a specific inhibitor of pan-caspase significantly reduced cell death caused by BITC. Colorimetric assay analyses also showed that the activities of caspase-3 and caspase-9 were elevated in BITC-treated CAR cells. An increase in ROS production and loss of mitochondria membrane potential (ΔΨm) occurred due to BITC exposure and was observed via flow cytometric analysis. Western blotting analyses demonstrated that the protein levels of Bax, Bad, cytochrome c, and cleaved caspase-3 were up-regulated, while those of Bcl-2, Bcl-xL and pro-caspase-9 were down-regulated in CAR cells after BITC challenge. In sum, the mitochondria-dependent pathway might contribute to BITC-induced apoptosis in human cisplatin-resistant oral cancer CAR cells.

Mechanistic evaluation of phytochemicals in breast cancer remedy: current understanding and future perspectives

Breast cancer is one of the most commonly diagnosed cancers around the globe and accounts for a large proportion of fatalities in women. Despite the advancement in therapeutic and diagnostic procedures, breast cancer still represents a major challenge. Current anti-breast cancer approaches include surgical removal, radiotherapy, hormonal therapy and the use of various chemotherapeutic drugs. However, drug resistance, associated serious adverse effects, metastasis and recurrence complications still need to be resolved which demand safe and alternative strategies. In this scenario, phytochemicals have recently gained huge attention due to their safety profile and cost-effectiveness. These phytochemicals modulate various genes, gene products and signalling pathways, thereby inhibiting breast cancer cell proliferation, invasion, angiogenesis and metastasis and inducing apoptosis. Moreover, they also target breast cancer stem cells and overcome drug resistance problems in breast carcinomas. Phytochemicals as adjuvants with chemotherapeutic drugs have greatly enhanced their therapeutic efficacy. This review focuses on the recently recognized molecular mechanisms underlying breast cancer chemoprevention with the use of phytochemicals such as curcumin, resveratrol, silibinin, genistein, epigallocatechin gallate, secoisolariciresinol, thymoquinone, kaempferol, quercetin, parthenolide, sulforaphane, ginsenosides, naringenin, isoliquiritigenin, luteolin, benzyl isothiocyanate, α-mangostin, 3,3'-diindolylmethane, pterostilbene, vinca alkaloids and apigenin.

Sulforaphane absorption and histone deacetylase activity following single dosing of broccoli sprout supplement in normal dogs

The role of epigenetic alterations during cancer has gained increasing attention and has resulted in a paradigm shift in our understanding of mechanisms leading to cancer susceptibility. Sulforaphane (SFN) is a naturally occurring isothiocyanate derived from the precursor glucosinolate, glucoraphanin (GFN), which is found in cruciferous vegetables such as broccoli. Sulforaphane has been shown to suppress tumour growth by several mechanisms including inhibiting histone deacetylases. The objective of this study was to provide a detailed analysis of sulforaphane absorption following a single oral dose of a broccoli sprout supplement in normal dogs. A single dose of broccoli sprout supplement (with active myrosinase) was orally administered to 10 healthy adult dogs. Blood and urine samples were collected prior to dosing, and at various time points post‐dosing. Plasma total SFN metabolite levels peaked at 4 h post‐consumption and were cleared by 24 h post‐consumption. Urinary SFN metabolites peaked at 4 h post‐consumption, and remained detectable at 24 and 48 h post‐supplement consumption. A trend for decrease in histone deacetylase activity was observed at 1 h post‐consumption and a significant decrease was observed at 24 h post‐consumption. The data presented herein indicate that oral SFN is absorbed in dogs, SFN metabolites are detectable in plasma and urine post‐dosing, and SFN and its metabolites have some effect on histone deacetylase activity following a single dose.

In Vitro Determination of Protein Conjugates in Human Cells by LC-ESI-MS/MS after Benzyl Isothiocyanate Exposure

Glucosinolates and their breakdown products, especially isothiocyanates (ITCs), are hypothesized to exert a broad range of bioactivities. However, physiological mechanisms are not yet completely understood. In this study, formation of protein conjugates after incubation with benzyl isothiocyanate (BITC) was investigated in vitro. A survey of protein conjugates was done by determining BITC cysteine and lysine amino acid conjugates after protein digestion. Therefore, a liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated. Stability studies showed that cysteine conjugates are not stable under alkaline conditions, and lysine conjugates did not show any correlation to pH values, although stability increased at low temperatures. Lysine conjugates were the preferred form of protein conjugates, and longer BITC exposure times led to higher amounts. Knowledge about the reaction sites of ITCs in eukaryotic cells may help to understand the mode of action of ITCs leading to health promoting as well as toxicological effects in humans.

Anticancer Activity of Sulforaphane: The Epigenetic Mechanisms and the Nrf2 Signaling Pathway

Sulforaphane (SFN), a compound derived from cruciferous vegetables that has been shown to be safe and nontoxic, with minimal/no side effects, has been extensively studied due to its numerous bioactivities, such as anticancer and antioxidant activities. SFN exerts its anticancer effects by modulating key signaling pathways and genes involved in the induction of apoptosis, cell cycle arrest, and inhibition of angiogenesis. SFN also upregulates a series of cytoprotective genes by activating nuclear factor erythroid-2- (NF-E2-) related factor 2 (Nrf2), a critical transcription factor activated in response to oxidative stress; Nrf2 activation is also involved in the cancer-preventive effects of SFN. Accumulating evidence supports that epigenetic modification is an important factor in carcinogenesis and cancer progression, as epigenetic alterations often contribute to the inhibition of tumor-suppressor genes and the activation of oncogenes, which enables cells to acquire cancer-promoting properties. Studies on the mechanisms underlying the anticancer effects of SFN have shown that SFN can reverse such epigenetic alterations in cancers by targeting DNA methyltransferases (DNMTs), histone deacetyltransferases (HDACs), and noncoding RNAs. Therefore, in this review, we will discuss the anticancer activities of SFN and its mechanisms, with a particular emphasis on epigenetic modifications, including epigenetic reactivation of Nrf2.

Role of EZH2 in cancer stem cells: from biological insight to a therapeutic target

Epigenetic modifications in cancer stem cells largely result in phenotypic and functional heterogeneity in many solid tumors. Increasing evidence indicates that enhancer of zeste homolog 2 (EZH2), the catalytic subunit of Polycomb repressor complex 2, is highly expressed in cancer stem cells of numerous malignant tumors and has a critical function in cancer stem cell expansion and maintenance. Here, we review up-to-date information regarding EZH2 expression patterns, functions, and molecular mechanisms in cancer stem cells in various malignant tumors and discuss the therapeutic potential of targeting EZH2 in tumors.

Sulforaphane metabolites cause apoptosis via microtubule disruption in cancer

Sulforaphane (SFN) inhibited growth in many cancers, but its half-life is 2 h in circulation. However, its metabolites, sulforaphane-cysteine (SFN-Cys) and sulforaphane-N-acetyl-cysteine (SFN-NAC) had longer half-lives and decreased the cell viability in both dose- and time-dependent manners in human prostate cancer. Flow cytometry assay revealed that these two SFN metabolites induced apoptosis with the features such as vacuolization, disappeared nuclear envelope, nuclear agglutination and fragmentation via transmission electron microscopy observation. Western blot showed that the sustained phosphorylation of ERK1/2 mediated by SFN metabolites caused activation and upregulation of cleaved Caspase 3 and downregulation of α-tubulin. High expression of α-tubulin was demonstrated to be positively correlated with cancer pathological grading. Both co-immunoprecipitation and immunofluorescence staining implicated the interaction between SFN metabolite-induced phosphorylated ERK1/2 and α-tubulin, and Caspase 3 cleavage assay showed that α-tubulin might be the substrate for cleaved Caspase 3. More, the SFN metabolite-mediated reduction of α-tubulin increased the depolymerization and instability of microtubules by microtubule polymerization assay. Reversely, microtubule-associated protein Stathmin-1 phosphorylation was increased via phosphorylated ERK1/2 and total Stathmin-1 was reduced, which might promote over-stability of microtubules. Immunofluorescence staining also showed that SFN metabolites induced the 'nest-like' structures of microtubule distribution resulting from the disrupted and aggregated microtubules, and abnormal nuclear division, suggesting that the disturbance of spindle formation and mitosis turned up. Thus, SFN-Cys and SFN-NAC triggered the dynamic imbalance of microtubules, microtubule disruption leading to cell apoptosis. These findings provided a novel insight into the chemotherapy of human prostate cancer.

Storage in high-barrier pouches increases the sulforaphane concentration in broccoli florets

Sulforaphane is a phytochemical that is usually found in cruciferous vegetables and is known to have a depressive effect on gastric cancer. Preliminary investigations showed that the sulforaphane concentration in broccoli (Brassica oleracea var. italica) florets increased under anoxia. Therefore, in the present study, we examined the effect of different atmospheric conditions on the sulforaphane concentration in broccoli and also tested whether there are concurrent effects on the concentration of ethanol, which is an unfavorable byproduct of fermentation. The sulforaphane concentration in broccoli florets was significantly elevated by 1.9- to 2.8-fold after 2 d of storage under hypoxia at ca. 0% O₂ and ca. 24% CO₂ at 20°C, whereas no such increase was observed following storage under normoxia at ca. 0% O₂ without CO₂ at 20°C. Furthermore, after 2 d, the sulforaphane concentration under hypoxia was 1.6- to 2.3-fold higher than that under normoxia. These results suggest that storage under hypoxia with high CO₂ levels can elevate the sulforaphane concentration in broccoli florets. However, the elevated sulforaphane concentration could not be maintained beyond 2 d. There was no significant difference in the concentration of ethanol between florets that were stored under hypoxia with/without CO₂ or normoxia at 2 d. However, the ethanol concentrations inside the pouches significantly increased between 2 d and 7 d. These findings indicate that the quality of broccoli florets can be improved through storage under hypoxia with high CO₂ levels at 20°C for 2 d.

Characteristic single glucosinolates from Moringa oleifera: Induction of detoxifying enzymes and lack of genotoxic activity in various model systems

Leaves of Moringa oleifera are used by tribes as biological cancer medicine. Scientific investigations with M. oleifera conducted so far have almost exclusively used total plant extracts. Studies on the activity of single compounds are missing. Therefore, the biological effects of the two main aromatic multi-glycosylated glucosinolates of M. oleifera were investigated in the present study. The cytotoxic effects of M. oleifera glucosinolates were identified for HepG2 cells (NRU assay), for V79-MZ cells (HPRT assay, SCE assay), and for two Salmonella typhimurium strains (Ames test). Genotoxic effects of these glucosinolates were not observed (Ames test, HPRT assay, and SCE assay). Reporter gene assays revealed a significant increase in the ARE-dependent promoter activity of NQO1 and GPx2 indicating an activation of the Nrf2 pathway by M. oleifera glucosinolates. Since both enzymes can also be induced via activation of the AhR, plasmids containing promoters of both enzymes mutated in the respective binding sites (pGL3enh-hNQO1-ARE, pGL3enh-hNQO1-XRE, pGL3bas-hGPX2-mutARE, pGL3bas-hGPX2-mutXRE) were transfected. Analyses revealed that the majority of the stimulating effects was mediated by the ARE motif, whereas the XRE motif played only a minor role. The stimulating effects of M. oleifera glucosinolates could be demonstrated both at the transcriptional (reporter gene assay, real time-PCR) and translational levels (enzyme activity) making them interesting compounds for further investigation.

Sulforaphane restores acetyl-histone H3 binding to Bcl-2 promoter and prevents apoptosis in ethanol-exposed neural crest cells and mouse embryos

Sulforaphane (SFN) is an isothiocyanate derived from cruciferous vegetables. SFN's cytoprotective properties have been demonstrated in several models associated with a variety of disorders. Our recent studies have shown that SFN protects against ethanol-induced oxidative stress and apoptosis in neural crest cells (NCCs), an ethanol-sensitive cell population implicated in Fetal Alcohol Spectrum Disorders (FASD). This study is designed to test the hypothesis that SFN can prevent ethanol-induced apoptosis in NCCs by inhibiting HDAC and increasing histone acetylation at the Bcl-2 promoter. We found that exposure to 50mM ethanol resulted in a significant increase in HDAC activities in NCCs. Treatment with SFN decreased the activities of HDAC in ethanol-exposed NCCs. We also found that SFN treatment significantly increased the expression of acetyl-histone H3 in NCCs treated with ethanol. ChIP-qPCR assay revealed that ethanol exposure significantly decreased acetyl-histone H3 binding to the Bcl-2 promoter while supplementing with SFN reversed the ethanol-induced reduction in acetyl-histone H3 binding to the Bcl-2 promoter. In addition, SFN treatment restored the expression of Bcl-2 in ethanol-exposed NCCs and diminished ethanol-induced apoptosis in NCCs. Treatment with SFN also significantly diminished apoptosis in mouse embryos exposed to ethanol in vivo. These results demonstrate that SFN can epigenetically restore the expression of Bcl-2 and attenuate ethanol-induced apoptosis by increasing histone acetylation at the Bcl-2 promoter and suggest that SFN may prevent FASD through epigenetic regulation of the expression of anti-apoptotic genes.

Recent progress in the discovery of myeloid differentiation 2 (MD2) modulators for inflammatory diseases

Myeloid differentiation protein 2 (MD2), together with Toll-like receptor 4 (TLR4), binds lipopolysaccharide (LPS) with high affinity, inducing the formation of the activated homodimer LPS-MD2-TLR4. MD2 directly recognizes the Lipid A domain of LPS, leading to the activation of downstream signaling of cytokine and chemokine production, and initiation of inflammatory and immune responses. However, excessive activation and potent host responses generate severe inflammatory syndromes such as acute sepsis and septic shock. MD2 is increasingly being considered as an attractive pharmacological target for the development of potent anti-inflammatory agents. In this Keynote review, we provide a comprehensive overview of the recent advances in the structure and biology of MD2, and present MD2 modulators as promising agents for anti-inflammatory intervention.

Combination cisplatin and sulforaphane treatment reduces proliferation, invasion, and tumor formation in epidermal squamous cell carcinoma

Epidermal squamous cell carcinoma is an extremely common type of cancer. Early tumors can be successfully treated by surgery, but recurrent disease is aggressive and resistant to therapy. Cisplatin is often used as a treatment, but the outcome is rarely satisfactory. For this reason new strategies are required. Sulforaphane is a diet-derived cancer prevention agent that is effective in suppressing tumor growth in animal models of skin cancer. We monitored the efficacy of sulforaphane and cisplatin as a combined therapy for squamous cell carcinoma. Both agents suppress cell proliferation, growth of cancer stem cell spheroids, matrigel invasion and migration of SCC-13 and HaCaT cells, and combination treatment is more efficient. In addition, SCC-13 cell derived cancer stem cells are more responsive to these agents than non-stem cancer cells. Both agents suppress tumor formation, but enhanced suppression is observed with combined treatment. Moreover, both agents reduce the number of tumor-resident cancer stem cells. SFN treatment of cultured cells or tumors increases apoptosis and p21Cip1 level, and both agents increase tumor apoptosis. We suggest that combined therapy with sulforaphane and cisplatin is efficient in suppressing tumor formation and may be a treatment option for advanced epidermal squamous cell carcinoma.

[Study on Effects and Mechanisms of Phytochemicals in Vegetables and Fruits in Preventing and Treating Lung Cancer]

无论是在全球还是我国，肺癌都是严重危害人类健康的恶性肿瘤。研究表明肺癌与环境因素以及生活方式密切相关，流行病学发现多吃蔬菜水果可以预防肺癌。蔬菜水果中含有丰富的植物化学物质，如异硫氰酸酯类、吲哚类、黄酮类等。这些植物化学物质通过调节与抗肿瘤相关的通路从而抑制肿瘤细胞增殖、诱导肿瘤细胞凋亡，降低肺癌发生的危险性。本文旨在对蔬菜水果中的植物化学物质在肺癌发生发展中的作用机制进行综述，为更好地预防和治疗肺癌提供理论依据与方向。

Anti-cancer effects of naturally derived compounds targeting histone deacetylase 6-related pathways

Alterations of the epigenetic machinery, affecting multiple biological functions, represent a major hallmark enabling the development of tumors. Among epigenetic regulatory proteins, histone deacetylase (HDAC)6 has emerged as an interesting potential therapeutic target towards a variety of diseases including cancer. Accordingly, this isoenzyme regulates many vital cellular regulatory processes and pathways essential to physiological homeostasis, as well as tumor multistep transformation involving initiation, promotion, progression and metastasis. In this review, we will consequently discuss the critical implications of HDAC6 in distinct mechanisms relevant to physiological and cancerous conditions, as well as the anticancer properties of synthetic, natural and natural-derived compounds through the modulation of HDAC6-related pathways.

Effect of broccoli sprouts on thyroid function, haematological, biochemical, and immunological parameters in rats with thyroid imbalance

Broccoli sprouts may exert a negative influence on thyroid function as they are a rich source of glucosinolates, in particular glucoraphanin. Under the study in a long-term experiment broccoli sprouts were tested as an element of rats diet, combined with deficient iodine, or sulfadimethoxine ingestion - two models of hypothyroidism. Evaluations were performed for serum TSH and thyroid hormones completed with analyzes of selected haematological, biochemical and immunological (IL-6, IL-10) parameters, as well as cytosolic glutathione peroxidase (GPX1), thioredoxin reductase (TR) in the thyroid, and plasma glutathione peroxidase (GPX3). A thermographic analysis was conducted to provide auxiliary indicators for determining a potential thyroid dysfunction under the specific experimental conditions. The levels of TSH, fT3 and fT4 remained unchanged following broccoli sprouts ingestion, which was even found to have a protective effect against sulfadimethoxine induced thyroid damage. Moreover, TR activity significantly increased in response to sprouts ingestion. In animals with hypothyroidism, broccoli sprouts were found to exert a beneficial influence on the antioxidant balance of the thyroid gland. In comparison to the rats with iodine deficiency, broccoli sprouts addition to the diet was observed to decrease IL-6 level. No significant differences in IL-10 concentration were determined. Neither addition of broccoli sprouts to the diet, nor sulfadimethoxine and iodine deficiency, caused negative changes in red blood cell parameters, glucose and uric acid concentrations, or kidney function. However, such a dietary intervention resulted in reduced WBC and PLT levels, and it may adversely interfere with liver function in rats, most likely due to a higher dietary intake of glucosinolates.

Autophagic cell death and premature senescence: New mechanism of 5-fluorouracil and sulforaphane synergistic anticancer effect in MDA-MB-231 triple negative breast cancer cell line

In view of the need for new, more effective therapies for the triple negative breast cancer treatment, the aim of the study was to evaluate the anticancer activity and mechanism of action of the sulforaphane and 5-fluorouracil combination in the triple negative breast cancer cell line MDA-MB-231. Changes in the number of live cells after alone and sequential treatment were determined by the MTT test. The Chou and Talaly method was used to identify the type of interaction. Confocal microscopy, flow cytometry, western blot and spectrophotometry were used to examine apoptosis, autophagy and premature senescence. The western blot method was applied to measure the level of enzymes that are crucial for the 5-fluorouracil activity. Sulforaphane and 5-fluorouracil have been shown to interact synergistically in the breast cancerMDA-MB-231 cell line, resulting in a significant reduction of the number of live cells compared to alone treatments. Sulforaphane has decreased the level of thymidylate synthetase, which was also observed in the case of the sequential sulforaphane and 5-fluorouracil treatment. Studies of the interaction mechanism have revealed that sulforaphane and 5-fluorouracil act synergistically in the MDA-MB-231 cells by inducing autophagic cell death and premature senescence.

Sulforaphane reverses gefitinib tolerance in human lung cancer cells via modulation of sonic hedgehog signaling

Gefitinib is a targeted anticancer drug that was developed as an effective clinical therapy for lung cancer. Numerous patients develop gefitinib resistance in response to treatment. Sulforaphane (SFN) is present in cruciferous vegetables, and has been demonstrated to inhibit the malignant growth of various types of cancer cells. To investigate the role of SFN in gefitinib resistance, a gefitinib-tolerant PC9 (PC9GT) cell model was established by continually exposing PC9 cells to gefitinib. Cell viability was measured using a cell proliferation assay. Components of the sonic hedgehog (SHH) signaling pathway and markers of lung cancer stem cells were detected via western blotting. SFN markedly inhibited the proliferation of PC9GT and PC9 cells in a dose-dependent manner; combination SFN/gefitinib treatment also markedly decreased PC9GT cell proliferation, compared with SFN or gefitinib administered alone (P<0.05). Western blot analysis revealed that the expression of SHH, Smoothened (SMO), zinc finger protein GLI1 (GLI1), GLI2, CD133 and CD44 were upregulated in PC9GT cells, as compared with in PC9 cells. Furthermore, SFN markedly inhibited the expression of SHH, SMO and GLI1 in PC9GT and PC9 cells in a dose dependent manner, and SFN combined with gefitinib markedly inhibited the expression of SHH, SMO, GLI1, CD133 and CD44 in PC9GT cells when compared with SFN or gefitinib monotherapy. The results of the present study demonstrated that SFN inhibits the proliferation of gefitinib-tolerant lung cancer cells via modulation of the SHH signaling pathway. Therefore, combined SFN and gefitinib therapy may be an effective approach for the treatment of lung cancer.

Chemoprevention with isothiocyanates - From bench to bedside

Isothiocyanates (ITCs) are naturally occurring hydrolization products from glucosinolates (GLSs) in brassicaceae and in epidemiological studies their intake has been weakly to moderately inversely correlated with the risk of colorectal cancer, prostate cancer and lung cancer. Numerous preclinical studies demonstrate chemopreventive mode of actions of ITCs, mainly related to a.) detoxification (induction of phase II enzymes), b.) anti-inflammatory properties by down-regulation of NFkappaB activity, c.) cyclin-mediated cell cycle arrest and d.) epigenetic modulation by inhibition of histone deacetylase activity. First prospective clinical trials were promising in patients with risk of prostate cancer recurrence. The glutathione-S-transferase gene expression seems to play a major role in the individual susceptibility towards ITCs. Safety issues are widely unclear and should be more addressed in future studies because ITCs can, in low concentrations, compromise the function of human immune cells and might impair genome stability.

MiR-21-Mediated Suppression of Smad7 Induces TGFβ1 and Can Be Inhibited by Activation of Nrf2 in Alcohol-Treated Lung Fibroblasts

BACKGROUND

We previously demonstrated that chronic alcohol ingestion augments TGFβ1 expression in the lung fibroblast and increases the risk of fibroproliferative disrepair in a mouse model of acute lung injury. The effect of alcohol on TGFβ1 is mitigated by treatment with sulforaphane (SFP), which can activate nuclear factor (erythroid-derived 2)-like 2 (Nrf2). However, the mechanisms by which alcohol amplifies, or SFP attenuates, TGFβ1 expression in the fibroblast are not known. MicroRNA (miR)-21 has been shown to inhibit Smad7, a TGFβ1 signaling inhibitor. In this study, we hypothesized that alcohol augments TGFβ1 expression through up-regulation of miR-21, which subsequently inhibits Smad7.

METHODS

Primary mouse lung fibroblasts were cultured ± alcohol ± SFP and assessed for gene expression of miR-21, and gene and/or protein expression of Nrf2, Nrf2-regulated antioxidant enzymes, Smad7, STAT3, and TGFβ1. NIH 3T3 fibroblasts were transfected with a miR-21 inhibitor and cultured ± alcohol. α-SMA, Smad7, and TGFβ1 protein expression were then assessed. In parallel, NIH 3T3 lung fibroblasts were transfected with Nrf2 silencing RNA (siRNA) and cultured ± alcohol ± SFP. Gene expression of miR-21, Nrf2, Smad7, and TGFβ1 was assessed.

RESULTS

MiR-21 gene expression was increased by 12-fold at 48 hours, and Smad7 gene expression and protein expression were reduced by ~30% in alcohol-treated fibroblasts. In parallel, inhibition of miR-21 attenuated alcohol-mediated decrease in Smad7 and increase in TGFβ1 and α-SMA protein expression. Treatment with SFP mitigated the effect of alcohol on miR-21, Smad7 and total and phosphorylated STAT3, and restored Nrf2-regulated antioxidant gene expression. Silencing of Nrf2 prevented the effect of SFP on miR-21, Smad7, and TGFβ1 gene expression in alcohol-treated NIH 3T3 fibroblasts.

CONCLUSIONS

Alcohol treatment increases TGFβ1 in fibroblasts, at least in part, through augmentation of miR-21, which then inhibits Smad7 expression. These effects can be attenuated by activation of Nrf2 with SFP.