cytochrome-c-t and sulforaphane

Sulforaphane, a natural isothiocyanate compound found in cruciferous vegetables, has been shown to exert cardioprotective effects during ischemic heart injury. However, the effects of sulforaphane on cardiotoxicity induced by doxorubicin are unknown. Thus, in the present study, H9c2 rat myoblasts were pre-treated with sulforaphane and its effects on cardiotoxicity were then examined. The results revealed that the pre-treatment of H9c2 rat myoblasts with sulforaphane decreased the apoptotic cell number (as shown by trypan blue exclusion assay) and the expression of pro-apoptotic proteins (Bax, caspase-3 and cytochrome c; as shown by western blot analysis and immunostaining), as well as the doxorubicin-induced increase in mitochondrial membrane potential (measured by JC-1 assay). Furthermore, sulforaphane increased the mRNA and protein expression of heme oxygenase-1 (HO-1, measured by RT-qPCR), which consequently reduced the levels of reactive oxygen species (ROS, measured using MitoSOX Red reagent) in the mitochondria which were induced by doxorubicin. The cardioprotective effects of sulforaphane were found to be mediated by the activation of the Kelch-like ECH-associated protein 1 (Keap1)/NF-E2-related factor-2 (Nrf2)/antioxidant-responsive element (ARE) pathway, which in turn mediates the induction of HO-1. Taken together, the findings of this study demonstrate that sulforaphane prevents doxorubicin-induced oxidative stress and cell death in H9c2 cells through the induction of HO-1 expression.

Topics: Animals; Anticarcinogenic Agents; Antioxidants; Apoptosis; bcl-2-Associated X Protein; Cardiotonic Agents; Caspase 3; Cell Line; Cytochromes c; Doxorubicin; Enzyme Activation; Heme Oxygenase-1; Intracellular Signaling Peptides and Proteins; Isothiocyanates; Kelch-Like ECH-Associated Protein 1; Membrane Potential, Mitochondrial; Myoblasts; NF-E2-Related Factor 2; Oxidative Stress; Rats; Reactive Oxygen Species; RNA, Messenger; Sulfoxides

Sulforaphane (SFN), an isothiocyanate that exists exclusively in cruciferous vegetables, may be the most promising preventive agent for bladder cancer (BC) to date. We previously observed that SFN dramatically inhibits human BC T24 cells in vitro. Our hypothesis is that SFN may attenuate BC growth. To test our hypothesis, we investigated the effect of SFN on human BC UM-UC-3 cell xenografts implanted into athymic mice. Sulforaphane extract was routinely prepared in our laboratory, and its content was measured with high-performance liquid chromatography. Athymic mice were injected subcutaneously with a UM-UC-3 cell suspension (2.0×10(6) cells/200 μL per mouse) and randomly divided into 2 groups. The positive control group was orally gavaged with water, and the treatment group was orally administered SFN from broccoli sprout (12 mg/kg body weight) for 5 weeks. At the end of the experiment, tumor tissues were harvested and processed for hematoxylin and eosin staining and immunohistochemistry. The average tumor volume decreased from 4.1±1.67 cm(3) in the positive control mice to 1.5±0.72 cm(3) in the SFN-treated mice, evidencing an inhibitory rate of 63%. The SFN extract also reduced the appearance of tumors, including karyopyknosis and angiogenesis. Sulforaphane extract induced caspase 3 and cytochrome c expression but reduced the expression of survivin. Sulforaphane extract retards the growth of UM-UC-3 xenografts in vivo, confirming its future potential in BC therapy.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Brassica; Caspase 3; Cell Line, Tumor; Cytochromes c; Humans; Inhibitor of Apoptosis Proteins; Isothiocyanates; Male; Mice; Mice, Nude; Phytotherapy; Plant Extracts; Repressor Proteins; Sulfoxides; Survivin; Thiocyanates; Thymus Gland; Urinary Bladder Neoplasms; Xenograft Model Antitumor Assays

Sulforaphane (SUL), an isothiocyanate naturally present in widely consumed vegetables, particularly broccoli, has recently attracted attention due to its inhibitory effects on tumor cell growth by inducing apoptosis. We investigated the ability of SUL to induce autophagy in human colon cancer cells and whether inhibition of autophagy could potentiate the proapoptotic effect of SUL.. The proliferation of cells treated with SUL was assessed by MTS assay and colony-forming assay. Apoptosis and caspases activity were investigated by flow cytometry. The formation of acidic vesicular organelles (AVOs) was detected in acridine-orange-stained cells by flow cytometry. Western blotting was used for the detection of light chain 3 (LC3). Localizations of LC3 and cytochrome c were analyzed by immunocytochemistry.. The proapoptotic effect was observed by treatment of cells with relatively high concentrations of SUL for long periods of time. After 16 h of treatment, evident formation of AVOs and recruitment of LC3 to autophagosomes, features of autophagy, were observed. Treatment of cells with a specific autophagy inhibitor (3-methyladenine) potentiated the proapoptotic effect of SUL, which was dependent on the activation of caspases and the release of cytochrome c to the cytosol.. The present results demonstrate induction of autophagy in colon cancer cells as a protective reaction against the proapoptotic effect of SUL, and consequently, the potentiation of the proapoptotic effect by autophagy inhibition. These findings provide a premise for use of autophagy inhibitors in combination with chemotherapeutic agents for treatment of colorectal cancer.

Topics: Adenine; Anticarcinogenic Agents; Apoptosis; Autophagy; Blotting, Western; Caspases; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Colony-Forming Units Assay; Cytochromes c; Flow Cytometry; Humans; Isothiocyanates; Sulfoxides; Thiocyanates

This work was designed to further study the mechanism by which sulforaphane (SFN) exerts a renoprotective effect against cisplatin (CIS)-induced damage. It was evaluated whether SFN attenuates the CIS-induced mitochondrial alterations and the impairment in the activity of the cytoprotective enzymes NAD(P)H: quinone oxidoreductase 1 (NQO1) and γ glutamyl cysteine ligase (γGCL). Studies were performed in renal epithelial LLC-PK1 cells and in isolated renal mitochondria from CIS, SFN or CIS+SFN treated rats. SFN effectively prevented the CIS-induced increase in reactive oxygen species (ROS) production and the decrease in NQO1 and γGCL activities and in glutathione (GSH) content. The protective effect of SFN on ROS production and cell viability was prevented by buthionine sulfoximine (BSO), an inhibitor of γGCL, and by dicoumarol, an inhibitor of NQO1. SFN was also able to prevent the CIS-induced mitochondrial alterations both in LLC-PK1 cells (loss of membrane potential) and in isolated mitochondria (inhibition of mitochondrial calcium uptake, release of cytochrome c, and decrease in GSH content, aconitase activity, adenosine triphosphate (ATP) content and oxygen consumption). It is concluded that the protection exerted by SFN on mitochondrial alterations and NQO1 and γGCL enzymes may be involved in the renoprotection of SFN against CIS.

Topics: Adenosine Triphosphate; Animals; Anticarcinogenic Agents; Antineoplastic Agents; Calcium Signaling; Cell Death; Cell Survival; Cisplatin; Cytochromes c; Enzyme Inhibitors; Glutamate-Cysteine Ligase; Glutathione; Isothiocyanates; Kidney; LLC-PK1 Cells; Membrane Potential, Mitochondrial; Mitochondria; Mitochondrial Diseases; NAD(P)H Dehydrogenase (Quinone); Oxygen Consumption; Rats; Sulfoxides; Swine; Thiocyanates

Sulforaphane (SUL) is an isothiocyanate naturally present in widely consumed vegetables, particularly in broccoli. SUL has recently been focused as a result of its inhibitory effects on tumor cell growth in vitro and in vivo. We used endothelial progenitor cells (EPCs) as an in vitro model to investigate the effect of SUL on the various steps of vasculogenesis and angiogenesis. Peripheral blood mononuclear cells from blood of normal human volunteers were plated on fibronectin-coated 100 mm dishes and incubated for 7 days. The viability of EPCs, treated with SUL at different doses, was assessed by MTS assay. Cell apoptosis was analyzed by flow cytometry. To determine the relative contributions of caspase-8 and caspase-9 pathways to SUL-induced apoptosis, the effect of caspase inhibitors was determined. The expression of apoptosis-related proteins (Bax, Bcl-2) was investigated by Western blot test. Finally, the effect of SUL on the ability of EPCs to form vascular-like structures on Matrigel was investigated. We clearly demonstrated that SUL induced the dose-dependent inhibition of EPCs' viability by induction of apoptosis. All caspases (caspase-3, -8, and -9) were activated during apoptosis induction by SUL, but the effect of caspase-9 was more prominent than that of caspase-8. Also, the expression of Bax was upregulated by SUL treatment. In addition to apoptosis induction, SUL dose-dependently inhibited the tube-like formation by EPCs on Matrigel. The present results demonstrate the antivasculogenic/antiangiogenic activity of SUL in vitro and open premise for the use of SUL as a multipotent anticancer agent that targets both cancer cells and the angiogenic endothelium.

Topics: Anticarcinogenic Agents; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Caspase 3; Caspase 8; Caspase 9; Cell Survival; Cells, Cultured; Collagen; Cytochromes c; Drug Combinations; Endothelial Cells; Endothelium, Vascular; Flow Cytometry; Humans; Isothiocyanates; Laminin; Lymphocytes; Monocytes; Proteoglycans; Proto-Oncogene Proteins c-bcl-2; Stem Cells; Sulfoxides; Thiocyanates

Despite the reported cytotoxicity and apoptosis-inducing properties of sulforaphane (SF) in colon cancer cells, the details concerning individual mechanisms and signaling cascades underlying SF-mediated apoptosis remain unclear. To understand different aspects of SF-induced proapoptic signaling in advanced colon carcinoma, we investigated its mechanisms in metastatic SW620 cell line. Our results indicate that in SW620 cells SF acts to induce multivariate cascades including DNA-damage response pathway whose proapoptotic signaling is nevertheless reduced owing to the mutant status of p53 and caspase-2-JNK pathway which seems to complement and enhance p53-dependent signaling, however only in wild-type p53. Furthermore, both pathways require the active role of mitochondria and do not depend on generation of ROS, making SF an attractive chemopreventive agent whose antitumor properties should be further investigated in colon cancer.

Topics: Anticarcinogenic Agents; Apoptosis; Caspase 2; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Cytochromes c; DNA Damage; Drug Screening Assays, Antitumor; Humans; Isothiocyanates; JNK Mitogen-Activated Protein Kinases; Membrane Potential, Mitochondrial; Oxidative Stress; Sulfoxides; Thiocyanates; Tumor Suppressor Protein p53

Sulforaphane, an isothiocyanate found in cruciferous vegetables, has been shown to induce phase 2 detoxication enzymes and inhibit the growth of chemically induced mammary tumors in rats, although the exact mechanisms of action of sulforaphane are not understood. In this study, we evaluated the effects of sulforaphane on cell growth and death in several human breast cancer cell lines and examined the hypothesis that sulforaphane acts as a histone deacetylase (HDAC) inhibitor in these cell lines. Sulforaphane treatment inhibited cell growth, induced a G(2)-M cell cycle block, increased expression of cyclin B1, and induced oligonucleosomal DNA fragmentation in the four human breast cancer cell lines examined, MDA-MB-231, MDA-MB-468, MCF-7, and T47D cells. Activation of apoptosis by sulforaphane in MDA-MB-231 cells seemed to be initiated through induction of Fas ligand, which resulted in activation of caspase-8, caspase-3, and poly(ADP-ribose) polymerase, whereas apoptosis in the other breast cancer cell lines was initiated by decreased Bcl-2 expression, release of cytochrome c into the cytosol, activation of caspase-9 and caspase-3, but not caspase-8, and poly(ADP-ribose) polymerase cleavage. Sulforaphane inhibited HDAC activity and decreased the expression of estrogen receptor-alpha, epidermal growth factor receptor, and human epidermal growth factor receptor-2 in each cell line, although no change in the acetylation of H3 or H4 was seen. These data suggest that sulforaphane inhibits cell growth, activates apoptosis, inhibits HDAC activity, and decreases the expression of key proteins involved in breast cancer proliferation in human breast cancer cells. These results support testing sulforaphane in vivo and warrant future studies examining the clinical potential of sulforaphane in human breast cancer.

Topics: Anticarcinogenic Agents; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Caspases; Cell Cycle; Cell Proliferation; Cyclin B; Cyclin B1; Cytochromes c; Cytosol; ErbB Receptors; Estrogen Receptor alpha; Fas Ligand Protein; Humans; Isothiocyanates; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Sulfoxides; Thiocyanates; Tumor Cells, Cultured

The present study reports a novel response to sulforaphane, a highly promising anticancer constituent of several edible cruciferous vegetables, in PC-3 and LNCaP human prostate cancer cells involving induction of autophagy. Exposure of PC-3 and LNCaP cells to sulforaphane resulted in several specific features characteristic of autophagy, including appearance of membranous vacuoles in the cytoplasm as revealed by transmission electron microscopy and formation of acidic vesicular organelles as revealed by fluorescence microscopy following staining with the lysosomotropic agent acridine orange. The sulforaphane-induced autophagy was associated with up-regulation, processing, and recruitment to autophagosomes of microtubule-associated protein 1 light chain 3 (LC3), which is a mammalian homologue of the yeast autophagy regulating protein Apg8/Aut7p. Treatment of cells with a specific inhibitor of autophagy (3-methyladenine) attenuated localization of LC3 to autophagosomes but exacerbated cytosolic release of cytochrome c as well as apoptotic cell death as revealed by analysis of subdiploid fraction and cytoplasmic histone-associated DNA fragmentation. In conclusion, the present study indicates that induction of autophagy represents a defense mechanism against sulforaphane-induced apoptosis in human prostate cancer cells. To the best of our knowledge, the present study is the first published report to convincingly document induction of autophagy by an isothiocyanate class of dietary chemopreventive agent.

Topics: Anticarcinogenic Agents; Apoptosis; Autophagy; Cell Line, Tumor; Cytochromes c; Humans; Isothiocyanates; Male; Microtubule-Associated Proteins; Prostatic Neoplasms; Sulfoxides; Thiocyanates

Sulforaphane, a constituent of many edible cruciferous vegetables, including broccoli, effectively suppresses proliferation of cancer cells in culture and in vivo by causing apoptosis induction, but the sequence of events leading to cell death is poorly defined. Here, we show that multidomain proapoptotic Bcl-2 family members Bax and Bak play a critical role in apoptosis induction by sulforaphane. This conclusion is based on the following observations: (a) sulforaphane treatment caused a dose- and time-dependent increase in the protein levels of both Bax and Bak and conformational change and mitochondrial translocation of Bax in SV40-transformed mouse embryonic fibroblasts (MEF) derived from wild-type mice to trigger cytosolic release of apoptogenic molecules (cytochrome c and Smac/DIABLO), activation of caspase-9 and caspase-3, and ultimately cell death; (b) MEFs derived from Bax or Bak knockout mice resisted cell death by sulforaphane, and (c) MEFs derived from Bax and Bak double knockout mice exhibited even greater protection against sulforaphane-induced cytochrome c release, caspase activation, and apoptosis compared with wild-type or single knockout cells. Interestingly, sulforaphane treatment also caused a dose- and time-dependent increase in the protein level of Apaf-1 in wild-type, Bax-/-, and Bak-/- MEFs but not in double knockout, suggesting that Bax and Bak might regulate sulforaphane-mediated induction of Apaf-1 protein. A marked decline in the protein level of X-linked inhibitor of apoptosis on treatment with sulforaphane was also observed. Thus, it is reasonable to postulate that sulforaphane-induced apoptosis is amplified by a decrease in X-linked inhibitor of apoptosis level, which functions to block cell death by inhibiting activities of caspases. In conclusion, the results of the present study indicate that Bax and Bak proteins play a critical role in initiation of cell death by sulforaphane.

Topics: Animals; Anticarcinogenic Agents; Apoptosis; Apoptosis Regulatory Proteins; Apoptotic Protease-Activating Factor 1; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; Carrier Proteins; Caspase 3; Caspase 9; Caspases; Cell Proliferation; Cells, Cultured; Chemoprevention; Complement Membrane Attack Complex; Complement System Proteins; Cytochromes c; Enzyme Activation; Epithelial Cells; Fibroblasts; Glycoproteins; Isothiocyanates; Male; Membrane Proteins; Mice; Mice, Knockout; Mitochondria; Mitochondrial Proteins; Prostate; Prostatic Neoplasms; Protein Conformation; Protein Transport; Proteins; Proto-Oncogene Proteins c-bcl-2; Sulfoxides; Thiocyanates

We have shown previously that sulforaphane (SFN), a constituent of many edible cruciferous vegetables including broccoli, suppresses growth of prostate cancer cells in culture as well as in vivo by causing apoptosis, but the sequence of events leading to cell death is poorly defined. Using PC-3 and DU145 human prostate cancer cells as a model, we now demonstrate, for the first time, that the initial signal for SFN-induced apoptosis is derived from reactive oxygen species (ROS). Exposure of PC-3 cells to growth-suppressive concentrations of SFN resulted in ROS generation, which was accompanied by disruption of mitochondrial membrane potential, cytosolic release of cytochrome c, and apoptosis. All these effects were significantly blocked on pretreatment with N-acetylcysteine and overexpression of catalase. The SFN-induced ROS generation was significantly attenuated on pretreatment with mitochondrial respiratory chain complex I inhibitors, including diphenyleneiodonium chloride and rotenone. SFN treatment also caused a rapid and significant depletion of GSH levels. Collectively, these observations indicate that SFN-induced ROS generation is probably mediated by a nonmitochondrial mechanism involving GSH depletion as well as a mitochondrial component. Ectopic expression of Bcl-xL, but not Bcl-2, in PC-3 cells offered significant protection against the cell death caused by SFN. In addition, SFN treatment resulted in an increase in the level of Fas, activation of caspase-8, and cleavage of Bid. Furthermore, SV40-immortalized mouse embryonic fibroblasts (MEFs) derived from Bid knock-out mice displayed significant resistance toward SFN-induced apoptosis compared with wild-type MEFs. In conclusion, the results of the present study indicate that SFN-induced apoptosis in prostate cancer cells is initiated by ROS generation and that both intrinsic and extrinsic caspase cascades contribute to the cell death caused by this highly promising cancer chemopreventive agent.

Topics: Acetylcysteine; Animals; Antioxidants; Apoptosis; BH3 Interacting Domain Death Agonist Protein; Carrier Proteins; Caspase 8; Caspases; Cell Line, Tumor; Cells, Cultured; Cytochromes c; Enzyme Activation; Humans; Isothiocyanates; Male; Membrane Potentials; Mice; Mice, Knockout; Mitochondria; Models, Biological; Prostatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Sulfoxides; Thiocyanates