cytochrome-c-t and Neoplasm-Metastasis

Triple-negative breast cancer (TNBC), defined as loss of estrogen, progesterone, and Her2 receptors, is a subtype of highly aggressive breast cancer with worse prognosis and poor survival rate. Macrophage migration inhibitory factor (MIF) is a pleiotropic pro-inflammatory cytokine aberrantly expressed in many solid tumors and known to promote tumor progression and metastasis. However, its role in TNBC progression and metastasis is unexplored. Here we have shown that in TNBC patients, MIF expression was significantly enriched in the tumor compared to adjacent normal tissue. Using publically available patient datasets, we showed that MIF overexpression correlates with worse survival in TNBC compared to other hormonal status. Orthotopic implantation of TNBC cells into MIF knockout mice showed reduced tumor growth compared to wild-type mice. In addition, we have shown that MIF downregulation inhibits TNBC growth and progression in a syngeneic mouse model. We further showed that CPSI-1306, a small-molecule MIF inhibitor, inhibits the growth of TNBC cells in vitro. Mechanistic studies revealed that CPSI-1306 induces intrinsic apoptosis by alteration in mitochondrial membrane potential, cytochrome c (Cyt c) release, and activation of different caspases. In addition, CPSI-1306 inhibits the activation of cell survival and proliferation-related molecules. CPSI-1306 treatment also reduced the tumor growth and metastasis in orthotopic mouse models of mammary carcinoma. CPSI-1306 treatment of tumor-bearing mice significantly inhibited TNBC growth and pulmonary metastasis in a dose-dependent manner. Histological analysis of xenograft tumors revealed a higher number of apoptotic cells in CPSI-1306-treated tumors compared to vehicle controls. Our studies, for the first time, show that MIF overexpression in TNBC enhances growth and metastasis. Taken together, our results indicate that using small molecular weight MIF inhibitors could be a promising strategy to inhibit TNBC progression and metastasis.

Topics: Animals; Apoptosis; Caspases; Cell Movement; Cell Survival; Cytochromes c; Disease Progression; Enzyme Activation; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; In Vitro Techniques; Inflammation; Intramolecular Oxidoreductases; Isoxazoles; Macrophage Migration-Inhibitory Factors; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; Morpholines; Neoplasm Metastasis; Neoplasm Transplantation; Treatment Outcome; Triple Negative Breast Neoplasms; Wound Healing

Ovarian cancer is the leading cause of gynaecology related cancer death worldwide. It is often diagnosed with an advanced stage. Apoptosis is a process of programmed cell death controlled by cell cycle machinery and several signaling pathways. Plant-derived compounds have received an increased interest in the treatment of cancer. Quercetin is a flavonoid present in fruits and vegetables which possess anticancer properties. Several studies have been demonstrated that quercetin induces apoptosis in various cancers. However, the apoptotic role of quercetin in metastatic ovarian cancer has not been extensively studied. In the present study, we investigated the apoptotic effect of quercetin on human metastatic ovarian cancer PA-1 cell line. Quercetin treatment (0-200 μM) for 24h decreases PA-1 cells viability in a dose-dependent manner. The effective dose was identified as 50 and 75 μM based on MTT assay. Quercetin induces apoptosis in metastatic ovarian cancer cells which were confirmed by AO/EtBr dual staining, DAPI staining and DNA fragmentation assay. Molecules involved in the intrinsic apoptotic pathway were altered by quercetin. Interestingly, antiapoptotic molecules such as Bcl-2, Bcl-xL were decreased while proapoptotic molecules such as caspase-3, caspase-9, Bid, Bad, Bax and cytochrome c were increased in the quercetin-treated PA-1 cells. Our results indicate that quercetin induces mitochondrial-mediated apoptotic pathway and thus it inhibits the growth of metastatic ovarian cancer cells.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 9; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cytochromes c; DNA Fragmentation; Female; Humans; Neoplasm Metastasis; Ovarian Neoplasms; Proto-Oncogene Proteins c-bcl-2; Quercetin

RBFOX3, an RNA-binding fox protein, plays an important role in the differentiation of neuronal development, but its role in the chemosensitivity of hepatocellular carcinoma (HCC) to 5-FU is unknown.. In this study, we examined the biological functions of RBFOX3 and its effect on the chemosensitivity of HCC cells to 5-FU in vitro and in a mouse xenograft model.. RBFOX3 was found to have elevated expression in HCC cell lines and tissue samples, and its knockdown inhibited HCC cell proliferation. Moreover, knockdown of RBFOX3 improved the inhibitory effect of 5-fluorouracil (5-FU) on cell proliferation, migration and invasion, and enhanced the apoptosis induced by 5-FU. However, overexpression of RBFOX3 reduced the inhibitory effect of 5-fluorouracil (5-FU) on cell proliferation, migration and invasion, and decreased the apoptosis induced by 5-FU. We further elucidated that RBFOX3 knockdown synergized with 5-FU to inhibit the growth and invasion of HCC cells through PI3K/AKT and epithelial-mesenchymal transition (EMT) signaling, and promote apoptosis by activating the cytochrome-c/caspase signaling pathway. Finally, we validated that RBFOX3 regulated 5-FU-mediated cytotoxicity in HCC in mouse xenograft models.. The findings from this study indicate that RBFOX3 regulates the chemosensitivity of HCC to 5-FU in vitro and in vivo. Therefore, targeting RBFOX3 may improve the inhibition of HCC growth and progression by 5-FU, and provide a novel potential therapeutic strategy for HCC.

Topics: Animals; Antigens, Nuclear; Apoptosis; Carcinoma, Hepatocellular; Caspases; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cytochromes c; Drug Resistance, Neoplasm; Epithelial-Mesenchymal Transition; Fluorouracil; Humans; Liver Neoplasms; Mice; Mice, Nude; Microscopy, Fluorescence; Neoplasm Metastasis; Nerve Tissue Proteins; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; RNA Interference; RNA, Small Interfering; Signal Transduction; Transplantation, Heterologous

Malignant glioma are linked to a high mortality rate. Therefore, it is necessary to explore and develop effective therapeutic strategy. Oroxyloside is a metabolite of oroxylin A. However, its inhibitory effects on cancer are little to be known. In the present study, we investigated the effects of oroxyloside on cell proliferation, migration, and apoptosis in vitro and in vivo in human glioma. The results indicated that oroxyloside significantly suppressed the proliferation of human glioma cells through inducing cell cycle arrest at G0/G1 phase through reducing Cyclin D1 and cyclin-dependent kinase 2 (CDK2) while enhancing p53 and p21 expressions. In addition, the migration of glioma cells was dramatically inhibited by oroxyloside in a dose-dependent manner, which was related to its modulation on extracellular matrix (ECM), as evidenced by up-regulated E-cadherin, and metastasis-associated protein 3 (MTA3), whereas down-regulated N-cadherin, Vimentin, Twist, alpha-smooth muscle actin (α-SMA) and Syndecan-2. Furthermore, oroxyloside treatment markedly induced apoptosis in glioma cells through improving Caspase-9, Caspase-3 and PARP cleavage, accompanied with high release of cytochrome c (Cyto-c) into cytoplasm and subsequently increase of apoptotic protease-activating factor 1 (Apaf-1). In vivo, oroxyloside administration significantly inhibited the glioma cell xenograft tumorigenesis through various signaling pathways, including suppression of Cyclin D1/CDK2 and ECM pathways, as well as potentiation of p53/p21 and Caspases pathways. Together, the findings above illustrated that oroxyloside, for the first time, was used as a promising candidate against human glioma.

Topics: Animals; Apoptosis; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cytochromes c; Disease Progression; Flavones; Glioma; Glucuronides; Humans; Male; Mice, Inbred BALB C; Mice, Nude; Neoplasm Metastasis; Signal Transduction; Xenograft Model Antitumor Assays

Doxycycline (DOX) exhibits anti-inflammatory, anti-tumor, and pro-apoptotic activity and is being tested in clinical trials as a chemotherapeutic agent for several cancers, including colon cancer.. In the current study, the chemotherapeutic activity of doxycycline was tested in a rat model of colon carcinogenesis, induced by colon specific cancer promoter, 1,2, dimethylhydrazine (DMH) as well as study the effect of DOX-alone on a separate group of rats.. Doxycycline administration in DMH-treated rats (DMH-DOX) unexpectedly increased tumor multiplicity, stimulated progression of colonic tumor growth from adenomas to carcinomas and revealed metastasis in small intestine as determined by macroscopic and histopathological analysis. DOX-alone treatment showed markedly enhanced chronic inflammation and reactive hyperplasia, which was dependent upon the dose of doxycycline administered. Moreover, immunohistochemical analysis revealed evidence of inflammation and anti-apoptotic action of DOX by deregulation of various biomarkers.. These results suggest that doxycycline caused chronic inflammation in colon, small intestine injury, enhanced the efficacy of DMH in tumor progression and provided a mechanistic link between doxycycline-induced chronic inflammation and tumorigenesis. Ongoing studies thus may need to focus on the molecular mechanisms of doxycycline action, which lead to its inflammatory and tumorigenic effects.

Topics: 1,2-Dimethylhydrazine; Animals; Body Weight; Carcinogenesis; Caspase 3; Caspase 9; Cell Proliferation; Chronic Disease; Colonic Neoplasms; Cytochromes c; Down-Regulation; Doxycycline; Immunohistochemistry; Inflammation; Intestine, Small; Male; Matrix Metalloproteinase 9; Neoplasm Metastasis; NF-kappa B; Rats, Sprague-Dawley; Tumor Suppressor Protein p53; Up-Regulation; Vascular Endothelial Growth Factor A

The therapeutic strategy for advanced nasopharyngeal carcinoma (NPC) is still challenging. It is an urgent need to uncover novel treatment targets for NPC. Therefore, understanding the mechanisms underlying NPC tumorigenesis and progression is essential for the development of new therapeutic strategies. Here, we showed that TP53-regulated inhibitor of apoptosis (TRIAP1) was aberrantly overexpressed and associated with poor survival in NPC patients. TRIAP1 overexpression promoted NPC cell proliferation and suppressed cell death in vitro and in vivo, whereas TRIAP1 knockdown inhibited cell tumorigenesis and enhanced apoptosis through the induction of mitochondrial fragmentation, membrane potential alteration and release of cytochrome c from mitochondria into the cytosol. Intersecting with our previous miRNA data and available bioinformatic algorithms, miR-320b was identified and validated as a negative regulator of TRIAP1. Further studies showed that overexpression of miR-320b suppressed NPC cell proliferation and enhanced mitochondrial fragmentation and apoptosis both in vitro and in vivo, while silencing of miR-320b promoted tumor growth and suppressed apoptosis. Additionally, TRIAP1 restoration abrogated the proliferation inhibition and apoptosis induced by miR-320b. Moreover, the loss of miR-320b expression was inversely correlated with TRIAP1 overexpression in NPC patients. This newly identified miR-320b/TRIAP1 pathway provides insights into the mechanisms leading to NPC tumorigenesis and unfavorable clinical outcomes, which may represent prognostic markers and potential therapeutic targets for NPC treatment.

Topics: Adult; Aged; Animals; Apoptosis; Carcinoma; Cell Line, Tumor; Cell Proliferation; Cell Transformation, Neoplastic; Cytochromes c; Cytosol; Disease Progression; Female; Gene Expression Regulation, Neoplastic; Humans; Intracellular Signaling Peptides and Proteins; Liver Neoplasms; Male; Membrane Potentials; Mice; Mice, Inbred BALB C; MicroRNAs; Middle Aged; Mitochondria; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Neoplasm Metastasis; Proportional Hazards Models; Signal Transduction

Monitoring the effects of treatment in malignant diseases is very important in study of the influence on the cell metabolism. Energy production in cancer cells is abnormally dependent on aerobic glycolysis. In addition to the dependency on glycolysis, cancer cells have other atypical metabolic characteristics. The purpose of the present study is to evaluation and analysis of the colon cancer cells under anti-angiogenic treatment, to establish the changes in the cellular energy metabolism and apoptotic potential. Anti-angiogenic drugs block the vascular endothelial growth factors, preventing the formation of new vessels.. We use immunohistochemical analysis of cytochrome c release and histoenzymatic analysis of adenosine triphosphatase (ATP-ase), succinate dehydrogenase (SDH), lactate dehydrogenase (LDH) enzymes. Colorectal tumor tissue samples were obtained by biopsy following the surgical procedures at the County Clinical Hospital of Oradea (Romania).. The obtained results show that the apoptotic potential of malignant cells increases during the anti-angiogenic treatment, in the same time the rate of glycolysis increases, due to installed hypoxia and reduced ATP synthesis. Our results have been confirmed by international studies too.. It was been demonstrated that the apoptotic potential of malignant cells increases significantly during anti-angiogenic treatment. There is growing evidence that cancer's "Achilles' heel" is tumor cell metabolism.

Topics: Adenosine Triphosphatases; Apoptosis; Colonic Neoplasms; Cytochromes c; Cytosol; Female; Humans; Immunohistochemistry; L-Lactate Dehydrogenase; Male; Middle Aged; Neoplasm Metastasis; Succinate Dehydrogenase

Bones are the most frequent site for breast cancer cells to settle and spread (metastasise); bone metastasis is considered to have a substantial impact on the quality of patients with common cancers. However, majority of breast cancers develop insensitivity to conventional chemotherapy which provides only palliation and can induce systemic side effects. In this study we evaluated the effect of free Dox and CaCO3/Dox nanocrystal on MCF-7 breast cancer using MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide), neural red, and lactate dehydrogenase colorimetric assays while DNA fragmentation and BrdU genotoxicity were also examined. Apoptogenic protein Bax, cytochrome C, and caspase-3 protein were analysed. Morphological changes of MCF-7 were determined using contrast light microscope and scanning and transmission electron microscope (SEM and TEM). The findings of the analysis revealed higher toxicity of CaCO3/Dox nanocrystal and effective cells killing compared to free Dox, morphological changes such as formation of apoptotic bodies, membrane blebbing, and absent of microvilli as indicated by the SEM analysis while TEM revealed the presence of chromatin condensation, chromosomal DNA fragmentation, cell shrinkage, and nuclear fragmentation. Results of TUNEL assay verified that most of the cells undergoes apoptosis by internucleosomal fragmentation of genomic DNA whereas the extent of apoptotic cells was calculated using the apoptotic index (AI). Therefore, the biobased calcium carbonate nanocrystals such as Dox carriers may serve as an alternative to conventional delivery system.

Topics: Antacids; Antibiotics, Antineoplastic; Apoptosis; Bone Neoplasms; Breast Neoplasms; Calcium Carbonate; Cell Line, Tumor; Cytochromes c; Doxorubicin; Drug Delivery Systems; Female; Humans; Mitochondrial Proteins; Nanoparticles; Neoplasm Metastasis; Neoplasm Proteins

Pancreatic cancer is one of the most malignant tumor diseases with the characters of aggressive growth and metastasis. With the inefficiency of the current therapeutics, new potential targets and new therapeutic agents for healing of pancreatic cancer are critically needed. We have previously found a small molecule, named 4-tert-butyl-2-[(cyclohexylamino) methyl]-6-methylphenol (TBMMP, NSC number: 48160), which can freeze the intermediate of Ras-GTP hydrolysis in the open non-signaling conformation with high affinity and high specificity in silico. In this work, we studied the effect and mechanism of TBMMP on two pancreatic cancer cell lines, CFPAC-1 and BxPC-3. The results showed that TBMMP could restrain the growth of the pancreatic cancer cells with IC(50) value 84.3 μM for CPFAC-1 and 94.5 μM for BxPC-3, respectively. Additionally, TBMMP increased cytochrome c release, reduced mitochondrial membrane potential, activated caspase-3, -9, elevated ROS and increased expression of the Bax in the pancreatic cancer cell lines. The results indicated that TBMMP induced the apoptosis of pancreatic cancer cells through the mitochondrial pathway. Further, we also found that TBMMP could suppress the metastasis of both pancreatic cancer cells in vitro. Taken together, we proposed that TBMMP might be a therapeutic potential lead for treating patients with pancreatic cancer.

Topics: Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Benzylamines; Cell Line, Tumor; Cell Survival; Cyclohexylamines; Cytochromes c; HEK293 Cells; Humans; Membrane Potential, Mitochondrial; Neoplasm Metastasis; Pancreatic Neoplasms; Reactive Oxygen Species; Wound Healing

Gambogic acid (GA) is considered a potent anti-tumor agent for its multiple effects on cancer cells in vitro and in vivo. Low concentrations of GA (0.3-1.2 µmol/L) can suppress invasion of human breast carcinoma cells without affecting cell viability. To get a whole profile of the inhibition on breast cancers, higher concentrations of GA and spontaneous metastatic animal models were employed. Treatment with GA (3 and 6 µmol/L) induced apoptosis in MDA-MB-231 cells and the accumulation of reactive oxygen species (ROS). Furthermore, GA induced PARP cleavage, activation of caspase-3, caspase-8, and caspase-9, as well as an increased ratio of Bax/Bcl-2. Moreover, the translocation of apoptotic inducing factor (AIF) and the release of cytochrome c (Cyt c) from mitochondria were observed, indicating that GA induced apoptosis through accumulation of ROS and mitochondrial apoptotic pathway. GA also inhibited cell survival via blocking Akt/mTOR signaling. In vivo, GA significantly inhibited the xenograft tumor growth and lung metastases in athymic BALB/c nude mice bearing MDA-MB-231 cells. Collectively, these data provide further support for the multiple effects of GA on human breast cancer cells, as well as for its potential application to inhibit tumor growth and prevent metastasis in human cancers.

Topics: Animals; Antineoplastic Agents; Apoptosis; Apoptosis Inducing Factor; bcl-2-Associated X Protein; Breast Neoplasms; Caspase 3; Caspase 8; Caspase 9; Cell Line, Tumor; Cell Survival; Cytochromes c; Female; Humans; Mice; Mice, Nude; Neoplasm Metastasis; Reactive Oxygen Species; Signal Transduction; Xanthones; Xenograft Model Antitumor Assays

We explored the mechanisms of apoptosis after Bcl-2 protein downmodulation in metastatic LNCaP-LN3 cells (LN3).. LNCaP, LNCaP-Pro5 (Pro5) and LN3 cells were cultured in 5% charcoal-stripped serum (CSS) or in R1881 (synthetic androgen) and bicalutamide (synthetic anti-androgen) and growth inhibition was assessed. Expression levels of androgen receptor (AR) and Bcl-2 were determined. LN3 cells were transfected with small interfering RNA Bcl-2 (siRNA Bcl-2) or control siRNA oligonucleotides. Rates of apoptosis and proliferation were obtained. Cytochrome c localization in treated and control cells was assessed +/- cyclosporine A (CsA). Caspases 9, 3, and poly (ADP-ribose) polymerase cleavage (PARP) were measured upon downmodulation of Bcl-2; and cell growth inhibition in vitro after Bcl-2 modulation combined with docetaxel chemotherapy was determined.. LN3 cells maintained growth under castrate conditions in vitro. AR protein amplification did not explain castrate-resistant LN3 cell growth. Bcl-2 protein levels in LN3 cells were significantly higher than in Pro5 cells, and were effectively downmodulated by siRNA Bcl-2. Subsequently increased apoptosis and decreased proliferation mediated by cytochrome c was noted and this was reversed by CsA. siRNA Bcl-2-transfected LN3 cells exhibited elevated levels of caspases 9, 3, and PARP cleavage. Exposure of LN3 cells to docetaxel led to increased apoptosis, and simultaneous downmodulation of Bcl-2 substantially enhanced this effect.. Downmodulation of Bcl-2 in metastatic castrate-resistant LNCaP-LN3 cells led to apoptosis via a cytochrome c-dependent pathway that was enhanced with docetaxel treatment.

Topics: Adenocarcinoma; Antineoplastic Agents; Apoptosis; Caspases; Cell Line, Tumor; Cell Proliferation; Cytochromes c; Docetaxel; Down-Regulation; Humans; Male; Neoplasm Metastasis; Poly(ADP-ribose) Polymerases; Prostatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Receptors, Androgen; RNA, Small Interfering; Signal Transduction; Taxoids

Metastatic breast cancers are hard to treat and almost always fatal. Chloroquine diphosphate, a derivative of quinine, has long been used as a potent and commonly used medicine against different human diseases. We therefore investigated the effects of chloroquine diphosphate on a highly metastatic mouse mammary carcinoma cell line. In vitro treatment of 4T1 mouse breast cancer cells with chloroquine diphosphate resulted in significant inhibition of cellular proliferation and viability, and induction of apoptosis in 4T1 cells in a time- and dose-dependent manner. Further analysis indicated that induction of apoptosis was associated with the loss of mitochondrial membrane potential, release of cytochrome c, and activation of caspase-9 and caspase-3, and cleavage of poly(ADP-ribose) polymerase. The effect of chloroquine diphosphate was then examined using a mice model in which 4T1 cells were implanted subcutaneously. Chloroquine diphosphate (25mg/kg and 50mg/kg, respectively) significantly inhibited the growth of the implanted 4T1 tumor cells and induced apoptosis in the tumor microenvironment. Moreover, the metastasis of tumor cells to the lungs was inhibited significantly and the survival of the mice enhanced. These data suggested that chloroquine diphosphate might have chemotherapeutic efficacy against breast cancer including inhibition of metastasis.

Topics: Animals; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Caspase 3; Caspase 9; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Chloroquine; Cytochromes c; Female; Mammary Neoplasms, Experimental; Membrane Potential, Mitochondrial; Mice; Mice, Inbred BALB C; Neoplasm Metastasis; Poly Adenosine Diphosphate Ribose; Xenograft Model Antitumor Assays

This study aimed to evaluate serum cytochrome c (cyto-c) levels as a novel role of tumor marker in patients with operable malignant tumors.. Serum cyto-c levels and lactate dehydrogenase (LD) activity were measured in a total of 257 cases (232 malignant and 25 benign). To identify the relationship between serum cyto-c and current tumor markers, six variables, such as gender, age, invasion, lymph node metastasis, distant metastasis, and LD, were analyzed by uni- and multivariate regression analysis methods. The test performance of serum cyto-c for the prediction of malignant behavior was evaluated by receiver operating characteristic (ROC) curves.. The serum cyto-c level was significantly higher in patients with malignant tumors than patients with benign tumors (20.6 vs. 15.5 ng/mL; P = 0.017, Mann-Whitney U test). No difference in the levels among subtypes of cancer was found, indicating that the change in serum cyto-c levels reflect cancer individually and not specific subtypes of cancer. The survival in patients with serum cyto-c levels over 40 ng/mL was poor (Kaplan-Meier test, P < 0.0001, Hazard ratio 16.76, 95% confidential interval 4.45-63.04). Multiple linear regression analyses disclosed the close association of serum cyto-c levels with invasion (P = 0.0004), metastasis (P = 0.0262) except for regional lymph node metastasis, and activity of serum LD (P < 0.0001), all of which are well known to represent malignant behavior. Conversely, the measurement of serum cyto-c was verified to have excellent diagnostic accuracy of 0.802 and 0.781 for the detection of invasion and metastasis (the area under curves of the constructed ROCs).. Serum cyto-c is a potent tumor marker as a predictor for malignant potential in cancers.

Topics: Aged; Biomarkers, Tumor; Carcinoembryonic Antigen; Cytochromes c; Disease Progression; Female; Humans; Lymph Nodes; Male; Middle Aged; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasms; Predictive Value of Tests; Treatment Outcome

Our study aimed to compare death signalling pathways triggered by lupulone in TRAIL-sensitive human colon cancer cells (SW480) and in their derived TRAIL-resistant metastatic cells (SW620). Lupulone (40 microg/ml) up-regulated expression of TRAIL DR4/DR5 death receptors at the cell surface of both cell lines, even in the absence of exogenous TRAIL ligand. Cell death induced by lupulone was inhibited in SW480 and SW620 cells exposed to blocking anti-DR4/DR5 antibodies. In SW480 cells, lupulone triggered cell death through a cross-talk between TRAIL-DR4/DR5 and the mitochondrial (intrinsic) pathways involving caspase-8 activation and Bid protein cleavage. As a consequence mitochondrial cytochrome c was released into the cytosol and activation of caspases-9 and -3 was observed. In the metastatic SW620 cells, lupulone restored the sensibility of these cells to TRAIL ligand and activated the extrinsic apoptotic pathway via DR4/DR5 death receptors and the involvement of the caspase-8/caspase-3 cascade. The demonstration that lupulone is able to activate TRAIL-death signalling pathways even in TRAIL resistant cancer cells highlights the potential of this natural compound for cancer prevention and therapy.

Topics: Antibodies, Blocking; Apoptosis; BH3 Interacting Domain Death Agonist Protein; Caspase Inhibitors; Caspases; Cell Line, Tumor; Colonic Neoplasms; Cytochromes c; Drug Screening Assays, Antitumor; Drug Synergism; Enzyme Inhibitors; Humans; Mitochondrial Membranes; Models, Biological; Neoplasm Metastasis; Oxidative Stress; Permeability; Reactive Oxygen Species; Receptors, TNF-Related Apoptosis-Inducing Ligand; Terpenes; TNF-Related Apoptosis-Inducing Ligand

Arsenic trioxide (As2O3) is an effective therapy in acute promyelocytic leukemia (APL), but its use in other malignancies is limited by the higher concentrations required to induce apoptosis. We have reported that trolox, an analogue of alpha-tocopherol, increases As2O3-mediated apoptosis in a variety of APL, myeloma and breast cancer cell lines, while non-malignant cells may be protected. In the present study, we extended previous results to show that trolox increases As2O3-mediated apoptosis in the P388 lymphoma cell line in vitro, as evidenced by decrease of mitochondrial membrane potential and release of cytochrome c. We then sought to determine whether this combination can enhance antitumor effects while protecting normal cells in vivo. In BDF1 mice, trolox treatment decreased As2O3-induced hepatomegaly, markers of oxidative stress and hepatocellular damage. In P388 tumor-bearing mice, As2O3 treatment prolonged survival, and the addition of trolox provided a further significant increase in lifespan. In addition, the combination of As2O3 and trolox inhibited metastatic spread, and protected the tumor-bearing mice from As2O3 liver toxicity. Our results suggest, for the first time, that trolox might prevent some of the clinical manifestations of As2O3-related toxicity while increasing its pro-apoptotic capacity and clinical efficacy in hematological malignancies.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Antioxidants; Apoptosis; Arsenic Trioxide; Arsenicals; Cell Line, Tumor; Chromans; Cytochromes c; Drug Synergism; Humans; Liver; Lymphoma; Membrane Potential, Mitochondrial; Mice; Neoplasm Metastasis; Neoplasm Transplantation; Oxides

Cell-cell adhesion is considered to be important in the development and maintenance of organ tissue. The spatial association between melanocytes and keratinocytes within human epidermis is achieved by homophilic interaction of E-cadherin molecules located on adjacent cells. In contrast, downregulation of E-cadherin expression in melanoma cells is considered as a key event in metastasis. Besides the adhesive properties, E-cadherin serves as a signal receptor linking to the cadherin-catenin signaling complex. As cadherins act as negative regulators of beta-catenin, a contribution to tumor formation seems likely. In the present study, it was tested whether ectopic expression of E-cadherin triggers apoptosis in human melanoma cell lines (G-361, JPC-298, SK-Mel-13). It was found that restoration of E-cadherin caused sensitization against drug-induced apoptosis. Particularly, the release of mitochondrial cytochrome c was increased in response to staurosporine. Moreover, activation of caspase-3 and caspase-8 was elevated. Similarly, DNA fragmentation, serving as a marker for advanced apoptosis, was amplified in cells transduced with E-cadherin. Interestingly, transduction with an E-cadherin construct lacking the extracellular domain showed no modified apoptosis. In conclusion, our findings suggest therapeutic strategies that enable expression of E-cadherin in order to sensitize human melanoma cells towards apoptosis.

Topics: Apoptosis; Cadherins; Caspase 3; Caspase 8; Catenins; Cell Adhesion; Cell Line, Tumor; Cytochromes c; Cytosol; DNA Fragmentation; Humans; Melanoma; Neoplasm Metastasis; Protein Structure, Tertiary; Staurosporine

Cell motility, growth, and proliferation are regulated by adhesion to the extracellular matrix. Detachment of adherent cells from extracellular matrix results in induction of apoptosis ("anoikis"). Transformed cells often show an anchorage-independent growth that enables them to acquire a motile, invasive phenotype. This phenotype has been associated with the altered expression and function of the integrin family of transmembrane proteins that mediate cell adhesion to the extracellular matrix. Although alpha4 integrin is normally expressed on leukocyte subpopulations, a number of metastatic melanomas and sarcomas express it as well. In this study, we demonstrated the expression of alpha4 integrins on the human osteosarcoma cell line SAOS and on metastatic osteosarcoma lesions from the lung and pericardium. We further demonstrated that alpha4 integrin is coupled to the beta1 subunit by biochemical analysis and by using a mAb directed against a combinatorial epitope unique to the alpha4beta1 molecule. SAOS cells undergo anoikis when adherence is denied. Anoikis involved the activation of caspase 3 and the release of cytochrome c from mitochondria. Treatment of non-adherent SAOS with an anti-alpha4 mAb increased anoikis while anti-beta1 integrin mAbs did not alter anoikis, thus indicating a novel function for the alpha4 subunit in the control of cell death. Since integrins can control cell migration, proliferation, and apoptosis these results demonstrate a potential role for alpha4 integrin during multiple aspects of osteosarcoma metastasis.

Topics: Anoikis; Antibodies, Monoclonal; Apoptosis; Cell Line; Cytochromes c; Heart Neoplasms; Humans; Integrin alpha4; Lung Neoplasms; Mitochondria; Neoplasm Metastasis; Osteosarcoma; Tumor Cells, Cultured