cytochrome-c-t and Pancreatic-Neoplasms

Pancreatic cancer is one of the fatal causes of global cancer-related deaths. Although surgery and chemotherapy are standard treatment options, post-treatment outcomes often end in a poor prognosis. In the present study, we investigated anti-pancreatic cancer and amelioration of radiation-induced oxidative damage by crocin. Crocin is a carotenoid isolated from the dietary herb saffron, a prospect for novel leads as an anti-cancer agent. Crocin significantly reduced cell viability of BXPC3 and Capan-2 by triggering caspase signaling via the downregulation of Bcl-2. It modulated the expression of cell cycle signaling proteins P53, P21, P27, CDK2, c-MYC, Cyt-c and P38. Concomitantly, crocin treatment-induced apoptosis by inducing the release of cytochrome c from mitochondria to cytosol. Microarray analysis of the expression signature of genes induced by crocin showed a substantial number of genes involved in cell signaling pathways and checkpoints (723) are significantly affected by crocin. In mice bearing pancreatic tumors, crocin significantly reduced tumor burden without a change in body weight. Additionally, it showed significant protection against radiation-induced hepatic oxidative damage, reduced the levels of hepatic toxicity and preserved liver morphology. These findings indicate that crocin has a potential role in the treatment, prevention and management of pancreatic cancer.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Carotenoids; Cell Cycle Proteins; Cell Line, Tumor; Cell Survival; Crocus; Cytochromes c; Female; Humans; Lipid Peroxidation; Liver Diseases; Mice; Mice, Nude; Pancreatic Neoplasms; Radiation Injuries; Signal Transduction; Transcriptome; Xenograft Model Antitumor Assays

To investigate apoptotic effects of berberine, a significant alkaloids component existing in Rhizoma coptidis, and its possible acting mechanism in insulinoma cells.. Different concentrations of berberine were used to treat mouse insulinoma (MIN6) cells for various period of time. The viability and apoptosis of the cells were analyzed using methylthiazolyldiphenvl-tetrazolium bromide assay, flow cytometry and enzyme-linked immuno sorbent assay. Changes in the relating pro- and anti-apoptosis proteins were detected by western-blotting.. High concentration (5 and 10 μmol/L) of berberine could induce the apoptosis of MIN6 cells through cytochrome C/Apaf-1/caspase-3 and apoptosis inducing factor (AIF) pathway.

Topics: Animals; Apoptosis; Apoptosis Inducing Factor; Apoptotic Protease-Activating Factor 1; Berberine; Caspase 3; Cell Survival; Cytochromes c; Dose-Response Relationship, Drug; Insulinoma; Mice; Pancreatic Neoplasms; Signal Transduction; Tumor Cells, Cultured

Tropomyosin-related kinase A (TrkA) plays important roles in tumor cell growth and survival signaling and contributes to chemo-resistance in pancreatic cancer. Therefore, we developed KK5101, a novel TrkA target inhibitor and assessed its anti-cancer effects and investigated underlying mechanism of action in pancreatic cancer. KK5101 was characterized to inhibit TrkA selectively and potently by protein binding assay. It effectively inhibited the growth and proliferation of pancreatic cancer cells. Also, KK5101 increased apoptosis with loss of mitochondrial membrane potential, as evidenced by increases of cytochrome c releases. It increased numbers of TUNEL-positive apoptotic cells, and cell death including early and late apoptosis by Annexin V assay. In addition, activation of the TrkA signaling cascades including p-AKT, p-MEK, and p-STAT3 were inhibited by KK5101 treatment in vitro, as well as ex vivo tumor spheroid models, resulting in potent induction of apoptosis. Importantly, KK5101 also significantly attenuated tumor growth of in vivo pancreatic cancer models. These findings indicate that KK5101 may exert antitumor effects by directly affecting cancer cell growth or survival via inhibition of TrkA signaling pathway. We therefore suggest that KK5101 is a novel therapeutic candidate for treating pancreatic cancer.

Topics: Animals; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cytochromes c; Gene Expression Regulation, Neoplastic; Humans; Membrane Potential, Mitochondrial; Mice; Pancreatic Neoplasms; Protein Kinase Inhibitors; Receptor, trkA; Recombinant Proteins; Signal Transduction; Xenograft Model Antitumor Assays

To investigate the effect of dihydroartemisinin on apoptosis of human pancreatic cancer cell line JF-305 and the role of reactive oxygen species(ROS) in the apoptosis of JF-305 cells induced by dihydroartemisinin. MTT assays were used to detect effect of different concentrations of dihydroartemisinin on cells proliferation of JF-305 lines. Cell cycle was detected by flow cytometry, and the apoptotic morphology was observed by Hoechst 333258 fluorescence staining. Annexin V fluorescence staining was used to detect the apoptosis changes of JF-305 cells, while DCFH-DA was used to detect the changes of ROS during apoptosis process. Western blot was used to detect the protein expression changes of Bax, Bcl-2, Cleaved caspase-3, Cleaved caspase-9 and Cyto C. As compared with the control group, the JF-305 cells proliferation was inhibited significantly(P<0.05) after treatment with different concentrations of dihydroartemisimin for 48 h; cell cycle was blocked in the G2/M phase; apoptotic morphology of nuclear condensation, aggregation, and fragmentation was found, and the apoptosis ratio was increased(P<0.05). DCFH-DA detection showed that the cell ROS was increased significantly after dihydroartemisinin treatment(P<0.05). Western blot results showed that the expression of Bcl-2 protein was down-regulated; the expression of Bax protein was up-regulated; the ration of Bax/Bcl-2 was increased and the protein expression levels of Cleaved caspase-3, Cleaved caspase-9 and Cyto C were increased after dihydroartemisinin treatment. Therefore, dihydroartemisinin could induce apoptosis of JF-305 cells, and the possible mechanism may be related to the formation and increasing of ROS.

Topics: Apoptosis; Artemisinins; bcl-2-Associated X Protein; Caspase 3; Caspase 9; Cell Proliferation; Cytochromes c; Humans; Pancreatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species

Pancreatic cancer has been found with abnormal expression or mutation in Ras proteins. Oncogenic Ras activation exploits their extensive signaling reach to affect multiple cellular processes, in which the mitogen-activated protein kinase (MAPK) signaling exerts important roles in tumorigenesis. Therapies targeted Ras are thus of major benefit for pancreatic cancer. Although small molecule APY606 has been successfully picked out by virtual drug screening based on Ras target receptor, its in-depth mechanism remains to be elucidated. We herein assessed the antitumor activity of APY606 against human pancreatic cancer Capan-1 and SW1990 cell lines and explored the effect of Ras-MAPK and apoptosis-related signaling pathway on the activity of APY606. APY606 treatment resulted in a dose- and time-dependent inhibition of cancer cell viability. Additionally, APY606 exhibited strong antitumor activity, as evidenced not only by reduction in tumor cell invasion, migration and mitochondrial membrane potential but also by alteration in several apoptotic indexes. Furthermore, APY606 treatment directly inhibited Ras-GTP and the downstream activation of MAPK, which resulted in the down-regulation of anti-apoptotic protein Bcl-2, leading to the up-regulation of mitochondrial apoptosis pathway-related proteins (Bax, cytosolic Cytochrome c and Caspase 3) and of cyclin-dependent kinase 2 and Cyclin A, E. These data suggest that impairing Ras-MAPK signaling is a novel mechanism of action for APY606 during therapeutic intervention in pancreatic cancer.

Topics: Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Cell Line, Tumor; Cytochromes c; Humans; MAP Kinase Signaling System; Pancreatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins p21(ras)

Previously, miR-345 was identified as one of the most significantly downregulated microRNAs in pancreatic cancer (PC); however, its functional significance remained unexplored.. miR-345 was overexpressed in PC cells by stable transfection, and its effect on growth, apoptosis and mitochondrial-membrane potential was examined by WST-1, Hoechst-33342/Annexin-V, and JC-1 staining, respectively. Gene expression was examined by quantitative reverse-transcription-PCR and/or immunoblotting, and subcellular fractions prepared and caspase-3/7 activity determined by commercially available kits. miR-345 target validation was performed by mutational analysis and luciferase-reporter assay.. miR-345 is significantly downregulated in PC tissues and cell lines relative to normal pancreatic cells, and its expression decreases gradually in PC progression model cell lines. Forced expression of miR-345 results in reduced growth of PC cells because of the induction of apoptosis, accompanied by a loss in mitochondrial membrane potential, cytochrome-c release, caspases-3/7 activation, and PARP-1 cleavage, as well as mitochondrial-to-nuclear translocation of apoptosis-inducing factor. These effects could be reversed by the treatment of miR-345-overexpressing PC cells with anti-miR-345 oligonucleotides. BCL2 was characterised as a novel target of miR-345 and its forced-expression abrogated the effects of miR-345 in PC cells.. miR-345 downregulation confers apoptosis resistance to PC cells, and its restoration could be exploited for therapeutic benefit.

Topics: Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 7; Cell Line, Tumor; Cell Nucleus; Cytochromes c; Down-Regulation; Gene Expression Regulation, Neoplastic; Humans; Membrane Potential, Mitochondrial; MicroRNAs; Mitochondria; Pancreatic Neoplasms; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases; Signal Transduction

Protein drugs as one of the most potent biotherapeutics have a tremendous potential in cancer therapy. Their application is, nevertheless, restricted by absence of efficacious, biocompatible, and cancer-targeting nanosystems. In this paper, we report that 2-[3-[5-amino-1-carboxypentyl]-ureido]-pentanedioic acid (Acupa)-decorated pH-responsive chimaeric polymersomes (Acupa-CPs) efficiently deliver therapeutic proteins into prostate cancer cells. Acupa-CPs had a unimodal distribution with average sizes ranging from 157-175 nm depending on amounts of Acupa. They displayed highly efficient loading of both model proteins, bovine serum albumin (BSA) and cytochrome C (CC), affording high protein loading contents of 9.1-24.5 wt.%. The in vitro release results showed that protein release was markedly accelerated at mildly acidic pH due to the hydrolysis of acetal bonds in the vesicular membrane. CLSM and MTT studies demonstrated that CC-loaded Acupa10-CPs mediated efficient delivery of protein drugs into PSMA positive LNCaP cells leading to pronounced antitumor effect, in contrast to their non-targeting counterparts and free CC. Remarkably, granzyme B (GrB)-loaded Acupa10-CPs caused effective apoptosis of LNCaP cells with a low half-maximal inhibitory concentration (IC50) of 1.6 nM. Flow cytometry and CLSM studies using MitoCapture™ revealed obvious depletion of mitochondria membrane potential in LNCaP cells treated with GrB-loaded Acupa10-CPs. The preliminary in vivo experiments showed that Acupa-CPs had a long circulation time with an elimination phase half-life of 3.3h in nude mice. PSMA-targeted, pH-responsive, and chimaeric polymersomes have appeared as efficient protein nanocarriers for targeted prostate cancer therapy.

Topics: Animals; Antigens, Surface; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Chemistry, Pharmaceutical; Cytochromes c; Dose-Response Relationship, Drug; Drug Carriers; Glutamate Carboxypeptidase II; Granzymes; Half-Life; Humans; Hydrogen-Ion Concentration; Inhibitory Concentration 50; Male; Membrane Potential, Mitochondrial; Mice, Nude; Nanoparticles; Pancreatic Neoplasms; Polyethylene Glycols; Polymers; Serum Albumin, Bovine; Solubility; Succinates

Gemcitabine is a first‑line chemotherapeutic agent used in the treatment of pancreatic cancer; however resistance of the disease to the drug often develops over time. Agents that can either enhance the effects of gemcitabine, or help to overcome the chemoresistance to the drug are needed for the successful treatment of pancreatic cancer. Oridonin is one such agent which is safe and multi‑targeted and has previously been shown to induce apoptosis in other tumor cells, through mitochondrial signaling pathways. The aims of the present study were to evaluate whether oridonin may enhance the effects of gemcitabine on pancreatic cancer in vitro and to investigate the possible mechanisms of this enhancement. In vitro studies have previously shown that oridonin can inhibit the proliferation of the Panc‑1 pancreatic cancer cell line, and potentiate gemcitabine‑induced apoptosis, which was shown to be associated with cell cycle arrest in the G1 phase. Western blot and quantitative polymerase chain reaction analyses demonstrated that the expression levels of the anti‑apoptotic gene Bcl‑2 and the Bcl‑2/Bax ratio in the oridonin and the oridonin plus gemcitabine groups were significantly downregulated as compared with the gemcitabine treatment and control groups. The expression levels of pro‑apoptotic genes Bax, cytochrome c (cyt c), and caspase‑3 and ‑9 in the oridonin and the combination groups were significantly upregulated as compared with the other two groups. The results suggested that oridonin improved the anti‑tumor effects of gemcitabine through the enhancement of gemcitabine‑induced apoptosis.This mechanism may be through the downregulation of Bcl‑2 expression and the upregulation of Bax expression, resulting in the reduction of the Bcl‑2/Bax ratio. These effects may promote the release of cyt c from the mitochondria into the cytoplasm thus triggering the mitochondrial apoptosis signaling pathway. Furthermore, caspase‑3 and ‑9 were shown to be activated as a result of the induction of apoptosis.

Topics: Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 9; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cytochromes c; Deoxycytidine; Diterpenes, Kaurane; Drug Synergism; G1 Phase Cell Cycle Checkpoints; Gemcitabine; Humans; Mitochondria; Pancreatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Signal Transduction

Antrodia camphorata is a fungus native to Taiwan, and it is considered a precious medicinal agent. We analyzed triterpenoids, polysaccharides and 1,3-β-D-glucan, three major effective components in A. camphorata extracts (ACE). ACE exhibited a selective cytotoxic effect on BxPC-3 human pancreatic cancer cells. ACE markedly inhibited the migration ability of BxPC-3 cells. Treatment of BxPC-3 cells with ACE resulted in the increase of cells in the sub-G1 phase and G2/M phase arrest. Apoptosis was confirmed by validating phosphatidylserine externalization, the observation of characteristic chromatin condensation, and nuclear DNA fragmentation. ACE induced apoptosis in BxPC-3 cells through a mitochondria-dependent pathway by triggering an appropriate balance of bax/bcl-2, cytochrome c release, activation of caspase-9 and -3, and poly(ADP-ribose) polymerase cleavage. ACE shows great therapeutic potential due to its cytotoxic effects against BxPC-3 cells which include inhibiting cell migration and inducing mitochondria-mediated apoptosis.

Topics: Antineoplastic Agents, Phytogenic; Antrodia; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Movement; Cytochromes c; DNA Fragmentation; Fruiting Bodies, Fungal; Glucans; Humans; Mitochondria; Pancreatic Neoplasms; Polysaccharides; Triterpenes

Gemcitabine is a first-line drug utilised in the chemotherapy of pancreatic cancer; however, this drug induces chemo-resistance and toxicity to normal tissue during treatment. Here, we firstly report that andrographolide (ANDRO) alone not only has anti-pancreatic cancer activity, but it also potentiates the anti-tumour activity of gemcitabine. Treatment with ANDRO alone inhibits proliferation of the pancreatic cancer cell lines in a dose- and time-dependent manner in vitro. Interestingly, ANDRO induces cell cycle arrest and apoptosis of pancreatic cancer cells by inhibiting STAT3 and Akt activation, upregulating the expression of p21(WAF1) and Bax, and downregulating the expression of cyclinD1, cyclinE, survivin, X-IAP and Bcl-2. Additionally, ANDRO combined with gemcitabine significantly induce stronger cell cycle arrest and more obvious apoptosis than each single treatment. The mechanistic study demonstrates that this synergistic effect is also dependent on the inhibition of STAT3 and Akt activations which subsequently regulates the pathways involved in the apoptosis and cell cycle arrest. Furthermore, both ANDRO alone and the combination treatments exhibit efficacious anti-tumour activity in vivo. Overall, our results provide solid evidence supporting that ANDRO alone or its combination with gemcitabine is a potential chemotherapeutic approach for treating human pancreatic cancer in clinical practice.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antimetabolites, Antineoplastic; Apoptosis; Blotting, Western; Cell Count; Cell Cycle; Cell Line, Tumor; Coloring Agents; Cytochromes c; Deoxycytidine; Diterpenes; Drug Synergism; Flow Cytometry; Gemcitabine; Gentian Violet; Humans; Ki-67 Antigen; Male; Mice; Mice, Inbred BALB C; Pancreatic Neoplasms; Proto-Oncogene Proteins c-akt; STAT3 Transcription Factor; Xenograft Model Antitumor Assays

Anti-apoptotic Bcl-2 family proteins have been reported to play an important role in apoptotic cell death of human malignancies. The aim of this study was to delineate the mechanism of anti-apoptotic Bcl-2 family proteins in pancreatic cancer (PaCa) cell survival. We first analyzed the endogenous expression and subcellular localization of anti-apoptotic Bcl-2 family proteins in six PaCa cell lines by Western blot. To delineate the functional role of Bcl-2 family proteins, siRNA-mediated knock-down of protein expression was used. Apoptosis was measured by Cell Death ELISA and Hoechst 33258 staining. In the results, the expression of anti-apoptotic Bcl-2 family proteins varied between PaCa cell lines. Mcl-1 knock-down resulted in marked cleavage of PARP and induction of apoptosis. Down-regulation of Bcl-2 or Bcl-xL had a much weaker effect. Simultaneous knock-down of Bcl-xL and Mcl-1 strongly induced apoptosis, but simultaneous knock-down of Bcl-xL/Bcl-2 or Mcl-1/Bcl-2 had no additive effect. The apoptosis-inducing effect of simultaneous knock-down of Bcl-xL and Mcl-1 was associated with translocation of Bax from the cytosol to the mitochondrial membrane, cytochrome c release, and caspase activation. These results demonstrated that Bcl-xL and Mcl-1 play an important role in pancreatic cancer cell survival. Targeting both Bcl-xL and Mcl-1 may be an intriguing therapeutic strategy in PaCa.

Topics: Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; Caspases; Cell Line, Tumor; Cytochromes c; Deoxycytidine; Enzyme Activation; Gemcitabine; Gene Knockdown Techniques; Humans; Mitochondria; Myeloid Cell Leukemia Sequence 1 Protein; Pancreatic Neoplasms

Pancreatic cancer is a highly aggressive malignant tumor. In the present study, we performed several methods, including CCK-8 assay, immunofluorescence technique, western blotting and flow cytometry, to determine the effects of VP16 (etoposide) on Panc-1 pancreatic cancer cells. The results demonstrated that VP16 inhibited the growth of and induced apoptosis in Panc-1 cells. Western blot analysis showed that VP16 inhibited the expression of Bcl-2 and enhanced the expression of Bax, caspases-3 and -9, cytochrome c and PARP. Notably, a strong inhibitory effect of VP16 on Panc-1 cells mainly occurred in non-CSCs. These data provide a new strategy for the therapy of pancreatic cancer.

Topics: Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 9; Cell Line, Tumor; Cytochromes c; Etoposide; Gene Expression Regulation, Neoplastic; Humans; Mitochondria; Neoplastic Stem Cells; Pancreatic Neoplasms; Signal Transduction

Oleanolic acid (OA), a pentacyclic triterpenoid, exhibits potential anti-tumor activity against many tumor cell lines. This study aims to examine the anti-tumor activity of OA on pancreatic cancer cells and its potential molecular mechanism. The results showed that the proliferation of Panc-28 cells was inhibited by OA in a concentration-dependent manner, with an IC50 (The half maximal inhibitory concentration) value of 46.35 µg ml(-1) , as determined by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The cell cycle was arrested in S phase and G2/M phase by OA. The study also showed that OA could induce remarkable apoptosis, evidenced by an increased percentage of early/late apoptotic cells, DNA ladder and nuclear morphology change. Further study revealed that OA could induce Reactive Oxygen Species (ROS) generation, mitochondrial depolarization, release of cytochrome C, lysosomal membrane permeabilization and leakage of cathepin B. The expression of apoptosis-correlated proteins was also affected in cells treated with OA, including activation of caspases-3/9 and cleavage of PARP. Further study confirmed that ROS scavenger vitamin C could reverse the apoptosis induced by OA in Panc-28 cells. Our results provide evidence that OA arrests the cell cycle and induces apoptosis, possibly via ROS-mediated mitochondrial and a lysosomal pathway in Panc-28 cells.

Topics: Apoptosis; Caspase 3; Caspase 9; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Membrane; Cell Proliferation; Cytochromes c; DNA Fragmentation; Humans; Lysosomes; Mitochondria; Oleanolic Acid; Pancreatic Neoplasms; Reactive Oxygen Species

Treatment of pancreatic cancer that cannot be surgically resected currently relies on minimally beneficial cytotoxic chemotherapy with gemcitabine. As the fourth leading cause of cancer-related death in the United States with dismal survival statistics, pancreatic cancer demands new and more effective treatment approaches. Resistance to gemcitabine is nearly universal and appears to involve defects in the intrinsic/mitochondrial apoptotic pathway. The bioactive sphingolipid ceramide is a critical mediator of apoptosis initiated by a number of therapeutic modalities. It is noteworthy that insufficient ceramide accumulation has been linked to gemcitabine resistance in multiple cancer types, including pancreatic cancer. Taking advantage of the fact that cancer cells frequently have more negatively charged mitochondria, we investigated a means to circumvent resistance to gemcitabine by targeting delivery of a cationic ceramide (l-t-C6-CCPS [LCL124: ((2S,3S,4E)-2-N-[6'-(1″-pyridinium)-hexanoyl-sphingosine bromide)]) to cancer cell mitochondria. LCL124 was effective in initiating apoptosis by causing mitochondrial depolarization in pancreatic cancer cells but demonstrated significantly less activity against nonmalignant pancreatic ductal epithelial cells. Furthermore, we demonstrate that the mitochondrial membrane potentials of the cancer cells were more negative than nonmalignant cells and that dissipation of this potential abrogated cell killing by LCL124, establishing that the effectiveness of this compound is potential-dependent. LCL124 selectively accumulated in and inhibited the growth of xenografts in vivo, confirming the tumor selectivity and therapeutic potential of cationic ceramides in pancreatic cancer. It is noteworthy that gemcitabine-resistant pancreatic cancer cells became more sensitive to subsequent treatment with LCL124, suggesting that this compound may be a uniquely suited to overcome gemcitabine resistance in pancreatic cancer.

Topics: Animals; Antimetabolites, Antineoplastic; Antineoplastic Agents; Apoptosis; Benzimidazoles; Blotting, Western; Carbocyanines; Cell Death; Cell Line, Tumor; Ceramides; Chromatography, High Pressure Liquid; Coloring Agents; Cytochromes c; Deoxycytidine; Female; Gemcitabine; Membrane Potential, Mitochondrial; Mice; Mice, Nude; Mitochondria; Oxygen Consumption; Pancreatic Neoplasms; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Spectrum Analysis; Xenograft Model Antitumor Assays

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

Alpinetin is a novel plant flavonoid derived from Alpinia katsumadai Hayata, found to possess strong anticancer effects. However, the antitumor effect of alpinetin on pancreatic cancer cells and the detailed mechanism remain unclear. The aim of this study was to investigate alpinetin's beneficial effect on pancreatic cancer and the possible molecular mechanism involved. Pancreatic cancer cell lines were treated with alpinetin at various doses and for different times, and the effect of alpinetin on cell growth inhibition, apoptosis and the cell cycle was determined. The expression of Bcl-2, Bcl-xL, XIAP and Bax, the activity of caspases and the levels of cytochrome c released were measured. The results showed that alpinetin inhibited the viability of three pancreatic cancer cell lines and induced apoptosis of BxPC-3 cells in a dose- and time-dependent manner. This was accompanied by regulation of the expression of Bcl-2, Bcl-xL, Bax and XIAP. Furthermore, alpinetin treatment led to the release of cytochrome c and activation of caspases-3, -8 and -9 proteins. Taken together, our studies indicate that alpinetin inhibited the proliferation of pancreatic cancer cells possibly through the regulation of the Bcl-2 family and XIAP expression, release of cytochrome c and the activation of caspases. Alpinetin may serve as a potential agent for the development of pancreatic cancer cell therapies.

Topics: Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; Caspase 3; Caspase 8; Caspase 9; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cytochromes c; Flavanones; Gene Expression Regulation, Neoplastic; Humans; Pancreatic Neoplasms; X-Linked Inhibitor of Apoptosis Protein

It has been previously shown that the naturally occurring antioxidant (-)-epigallocatechin-3-gallate (EGCG), found in green tea, and pterostilbene, a stilbenoid derived from blueberries, inhibit pancreatic cancer in vitro when used individually. We hypothesized that the combination of EGCG and pterostilbene would reveal additive effects in vitro.. Using the pancreatic cancer cell lines MIA PaCa-2 and PANC-1, efficacy and synergism were evaluated for cell proliferation and viability (3-(4,5-dimethyltiazol-2-y1)-2,5-diphenltetrazolium bromide assays, cell cycle analysis) and mitochondrial apoptosis (mitochondrial depolarization, cytochrome C release, caspase-3/7 activity, cell death detection using enzyme-linked immunosorbent assay).. Cell proliferation assays revealed significant additive antiproliferative effects with pterostilbene and EGCG in both cell lines at the later, 72-h, point (P < 0.05). MIA underwent S-phase arrest with the combination (10-12% increase); however, cell cycle arrest was not observed in PANC. The combination induced mitochondrial depolarization and upregulated cytochrome C (P < 0.05) in MIA, but these effects were not observed in PANC. EGCG increased caspase-3/7 in MIA; however, the combination did not significantly increase the activity in either cell line (P < 0.05). Apoptosis was only observed in PANC (P < 0.05). The reduction in proliferation in MIA in the 3-(4,5-dimethyltiazol-2-y1)-2,5-diphenltetrazolium bromide assays with the combination indicated that cell death occurs, possibly through another mechanism.. Our results are encouraging regarding the future use of EGCG and pterostilbene to improve traditional pancreatic cancer therapies. In conclusion, EGCG and pterostilbene have additive, antiproliferative effects in vitro and alter the apoptotic mechanisms in both cell lines by modulation at different points in the mechanism.

Topics: Anticarcinogenic Agents; Carcinoma; Caspases; Catechin; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cytochromes c; DNA Fragmentation; Drug Evaluation, Preclinical; Humans; Pancreatic Neoplasms; Stilbenes

Pancreatic cancer is considered a lethal and treatment-refractory disease. To obtain a potent anticancer drug, the cytotoxic effect of 2-(benzo[d]oxazol-3(2H)-ylmethyl)-5-((cyclohexylamino)methyl)benzene-1,4-diol, dihydrochloride (NSC48693) on human pancreatic cancer cells CFPAC-1, MiaPaCa-2, and BxPC-3 was assessed in vitro. The proliferation of CFPAC-1, MiaPaCa-2, and BxPC-3 is inhibited with IC(50) value of 12.9±0.2, 20.6±0.3, and 6.2±0.6 µM at 48 h, respectively. This discovery is followed with additional analysis to demonstrate that NSC48693 inhibition is due to induction of apoptosis, including Annexin V staining, chromatins staining, and colony forming assays. It is further revealed that NSC48693 induces the release of cytochrome c, reduces mitochondrial membrane potential, generates reactive oxygen species, and activates caspase. These results collectively indicate that NSC48693 mainly induces apoptosis of CFPAC-1, MiaPaCa-2, and BxPC-3 cells by the mitochondrial-mediated apoptotic pathway. Excitingly, the study highlights an encouraging inhibition effect that human embryonic kidney (HEK-293) and liver (HL-7702) cells are more resistant to the antigrowth effect of NSC48693 compared to the three cancer cell lines. From this perspective, NSC48693 should help to open up a new opportunity for the treatment of patients with pancreatic cancer.

Topics: Antineoplastic Agents; Apoptosis; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cytochromes c; Humans; Membrane Potential, Mitochondrial; Pancreatic Neoplasms; Reactive Oxygen Species

The antitumor activity of oleanolic (OA) has attracted attention due to its marked antitumor effects and pharmacological safety. In the present study, the effects of the combination of OA and 5-fluorouracil (5-FU) on Panc-28 human pancreatic cells were studied. The results showed that combined use of OA and 5-FU synergistically potentiated cell death effects on Panc-28 cells, and the pro-apoptotic effects were also increased. Further study revealed that the combined treatment could enhance mitochondrial depolarization, lysosomal membrane permeabilization (LMP) and leakage of cathepin D, while the release of cytochrome C did not display significant changes. The expression of apoptosis related proteins was also affected in cells treated with the combination of OA and 5-FU, including activation of caspases-3 and the expression of Bcl-2/Bax, survivin and NF-κB. Our results provide evidence that combination of OA and 5-FU may serve as a novel strategy for the treatment of pancreatic cancer.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Cathepsin D; Cell Proliferation; Cytochromes c; Drug Screening Assays, Antitumor; Fluorouracil; Humans; Inhibitor of Apoptosis Proteins; Intracellular Membranes; Lysosomes; NF-kappa B; Oleanolic Acid; Pancreatic Neoplasms; Permeability; Proto-Oncogene Proteins c-bcl-2; Survivin; Tumor Cells, Cultured

Pancreatic cancer is one of the leading cancer-related causes of death due to high chemo-resistance and fast metastasation. Nemorosone, a polycyclic polyprenylated acylphloroglucinol, has recently been identified as a promising anticancer agent. Here, we examine its growth-inhibitory effects on pancreatic cancer cells. Based on transcription profiling, a molecular mode of action is proposed.. Nemorosone cytotoxicity was assessed by the resazurin proliferation assay on pancreatic cancer cells and fibroblasts. Apoptosis was determined by Annexin V/propidium iodide staining as well as cytochrome c and caspase activation assays. Staining with the voltage-dependent dye JC-1 and fluorescence microscopy were used to detect effects on mitochondrial membrane potential. Total RNA was isolated from treated cell lines and subjected to microarray analysis, subsequent pathway identification and modelling. Gene expression data were validated by quantitative polymerase chain reaction and siRNA-mediated gene knock-down.. Nemorosone significantly inhibited cancer cell growth, induced cytochrome c release and subsequent caspase-dependent apoptosis, rapidly abolished mitochondrial membrane potential and elevated cytosolic calcium levels, while fibroblasts were largely unaffected. Expression profiling revealed 336 genes to be affected by nemorosone. A total of 75 genes were altered in all three cell lines, many of which were within the unfolded protein response (UPR) network. DNA damage inducible transcript 3 was identified as a key regulator in UPR-mediated cell death.. Nemorosone could be a lead compound for the development of novel anticancer drugs amplifying the already elevated UPR level in solid tumours, thus driving them into apoptosis. This study forms the basis for further investigations identifying nemorosone's direct molecular target(s).

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Base Sequence; Benzophenones; Calcium; Caspases; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cytochromes c; Drug Screening Assays, Antitumor; Endoplasmic Reticulum; Gene Expression Profiling; Humans; Membrane Potential, Mitochondrial; Oligonucleotide Array Sequence Analysis; Pancreatic Neoplasms; RNA Interference; RNA, Small Interfering; Stress, Physiological; Transcription Factor CHOP; Unfolded Protein Response

Gemcitabine is currently the best treatment available for pancreatic cancer, but causes high toxicity. Agents that can enhance the effects of gemcitabine with no or low toxicity are needed for the treatment of pancreatic cancer. Emodin, a natural anthraquinone derivative, is one such agent that has been shown to induce apoptosis in other tumor cells via down-regulation of Bcl-2/Bax and promoting the release of Cytochrome C (CytC), but with very low toxicity. The aim of this study was to evaluate whether emodin can enhance the effect of gemcitabine on pancreatic cancer in vitro and in vivo and to investigate the possible mechanisms of the enhancement. In vitro, emodin inhibited the proliferation of the SW1990 cell line and potentiated the apoptosis induced by gemcitabine, which was demonstrated by activation of caspase-3 in the combination group. In vivo, tumors from nude mice subcutaneously injected with SW1990 cells and treated with a combination of emodin (40 mg/kg) and gemcitabine (80 mg/kg) showed significant reductions in volume, Ki-67 proliferation index and expression of the Bcl-2/Bax ratio (compared with tumors from mice treated with sodium chloride, emodin alone (40 mg/kg) or gemcitabine alone (125 mg/kg), which induced increasing release of CytC from the mitochondria to the cytoplasm and triggered caspase-3 activation leading to apoptosis. Taken together, our results suggest that emodin improved the anti-tumor effect of gemcitabine, even at a lower dose of gemcitabine which could decrease the toxicity of chemotherapy, on transplanted tumors of the SW1990 cell line through the enhancement of apoptosis induced by gemcitabine, the mechanism of which may be through down-regulation of the Bcl-2/Bax ratio and promoting release of CytC from the mitochondria into the cytoplasm.

Topics: Animals; Antimetabolites, Antineoplastic; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Cell Line, Tumor; Cell Proliferation; Cytochromes c; Deoxycytidine; Drug Synergism; Emodin; Female; Gemcitabine; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Pancreatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Xenograft Model Antitumor Assays

Obacunone is one of the oxygenated triterpenoids found in rutaceae family. It has been demonstrated for various biological activities including inhibition of cancer cells proliferation and tumor. The current study is an attempt to understand the mode of cytotoxicity of obacunone using cultured pancreatic cancer (MDA Panc-28) cells. Obacunone exhibited dose and time dependant inhibition of Panc-28 cells proliferation . This was also associated with phosphatidylserine translocation from inner surface of plasma membrane to outer surface in the treated cells, suggesting the involvement of apoptosis. Analysis of cells treated with 50 and 100 μM of obacunone suggests activation of initiator caspase-9 and effector caspase-3, indicating involvement of caspases induced apoptosis. Obacunone upregulated expression of tumor suppressor protein p53, pro-apoptotic protein Bax and downregulated anti-apoptotic protein Bcl2. Furthermore, release of cytochrome-c into cytosol was observed in the cells treated with obacunone. It also resulted in down regulation of vital inflammatory mediators such as NFκB and Cox-2 suggesting the anti-inflammatory potential. For the first time, current study provides an evidence on activation of caspase dependant, cytochrome-c mediated intrinsic apoptosis and anti-inflammatory activity in Panc-28 cells by citrus obacunone. Induction of cytotoxicity and apoptosis was also confirmed by fluorescent tagged microscopic images of obacunone treated Panc-28 cells.

Topics: Anti-Inflammatory Agents; Apoptosis; Benzoxepins; Caspase 3; Caspase 9; Cell Line, Tumor; Cell Proliferation; Citrus; Cytochromes c; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; Humans; Inflammation Mediators; Limonins; Pancreatic Neoplasms; Time Factors

Oxymatrine, an isolated extract from traditional Chinese herb Sophora Flavescens Ait, has been traditionally used for therapy of anti-hepatitis B virus, anti-inflammation and anti-anaphylaxis. The present study was to investigate the anti-cancer effect of oxymatrine on human pancreatic cancer PANC-1 cells, and its possible molecular mechanism.. The effect of oxymatrine on the viability and apoptosis was examined by methyl thiazolyl tetrazolium and flow cytometry analysis. The expression of Bax, Bcl-2, Bcl-x (L/S), Bid, Bad, HIAP-1, HIAP-2, XIAP, NAIP, Livin and Survivin genes was accessed by RT-PCR. The levels of cytochrome c and caspase 3 protein were assessed by Western blotting.. Oxymatrine inhibited cell viability and induced apoptosis of PANC-1 cells in a time- and dose-dependent manner. This was accompanied by down-regulated expression of Livin and Survivin genes while the Bax/Bcl-2 ratio was upregulated. Furthermore, oxymatrine treatment led to the release of cytochrome c and activation of caspase-3 proteins.. Oxymatrine can induce apoptotic cell death of human pancreatic cancer, which might be attributed to the regulation of Bcl-2 and IAP families, release of mitochondrial cytochrome c and activation of caspase-3.

Topics: Alkaloids; Antineoplastic Agents; Apoptosis; Caspase 3; Cell Growth Processes; Cell Line, Tumor; Cytochromes c; Dose-Response Relationship, Drug; Humans; Inhibitor of Apoptosis Proteins; Pancreatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Quinolizines; RNA, Messenger

Pancreatic adenocarcinoma is one of the most common malignancies worldwide. Gemcitabine is currently the standard first-line chemotherapeutic agent for pancreatic cancer. However, gemcitabine can induce activation of Akt and nuclear factor-κB (NF-κB), which is associated with its chemoresistance. It has been reported that gemcitabine combination therapies result in improved survival outcomes in pancreatic cancer. Therefore, agents that can either enhance the effects of gemcitabine or overcome chemoresistance to the drug are needed for the treatment of pancreatic cancer. Emodin is an active component of Chinese medicinal herbs and can inhibit the activation of Akt and NF-κB. In this study, we investigated whether emodin could enhance the anticancer effect of gemcitabine on pancreatic cancer in vivo. We demonstrated that treatment of gemcitabine combined with emodin efficiently suppressed tumor growth in mice inoculated with pancreatic tumor cells. This treatment paradigm promoted apoptotic cell death and mitochondrial fragmentation. Furthermore, it reduced phosphorylated-Akt (p-Akt) level, NF-κB activation and Bcl-2/Bax ratio, increased caspase-9 and -3 activation, Cytochrome C (CytC) release occurred in combination therapy. Collectively, emodin enhanced the activity of gemcitabine in tumor growth suppression via inhibition of Akt and NF-κB activation, thus promoting the mitochondrial-dependent apoptotic pathway. Therefore, our findings may provide new insights into understanding the pharmacological regulation of emodin on gemcitabine-mediated proapoptosis in pancreatic cancer and may aid in the design of new therapeutic strategies for the intervention of human pancreatic cancers.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Body Weight; Caspase 3; Cell Line, Tumor; Cytochromes c; Emodin; Female; Humans; Mice; NF-kappa B; Pancreatic Neoplasms; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Rheum; Tumor Burden; Xenograft Model Antitumor Assays

Higd-1a (hypoxia induced gene domain family-1a) is a mitochondrial inner membrane protein with a conformation of N-terminal outside-C-terminal outside and loop inside. There are four Higd genes, Higd-1a, -1b, -1c and -2a, in the mouse. Higd-1a and -2a are expressed primarily in the brain, heart, kidney and leukocytes. HIF (hypoxia-inducible factor) overexpression induced the endogenous expression and promoter activity of Higd-1a. Mutation of the HRE (hypoxia-response element) site at -32bp in the Higd-1a promoter reduced the promoter activity, suggesting that transcription of Higd-1a is regulated by binding of the transcription factor HIF to the HRE. Higd-1a promoted cell survival under hypoxia. RAW264.7 cells stably transfected with Higd-1a underwent less apoptosis than control cells in a hypoxic condition, and hypoxia-induced apoptosis was strongly enhanced when endogenous Higd-1a was silenced by siRNA. The survival effect of Higd-1a was completely abolished by deletion of the 26 N-terminal amino acids, and we showed that Higd-1a increased survival by inhibiting cytochrome C release and reducing the activities of caspases. However, expression of Bcl-2, Bax, Bad, and BNIP3 and translocation of AIF were unaffected under the same conditions. Higd-2a also enhanced cell survival under hypoxia. Cells transfected with Higd-2a underwent less apoptosis than control cells in hypoxic conditions, and hypoxia-induced apoptosis increased when endogenous Higd-2a was depleted. Together these observations indicate that Higd-1a is induced by hypoxia in a HIF-dependent manner and its anti-apoptotic effect results from inhibiting cytochrome C release and reducing caspase activities.

Topics: Adenocarcinoma; Amino Acid Sequence; Animals; Apoptosis; Blotting, Western; Caspases; Cell Hypoxia; Cells, Cultured; Cytochromes c; DNA, Mitochondrial; Enzyme Activation; Flow Cytometry; HeLa Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Intracellular Signaling Peptides and Proteins; Macrophages; Membrane Proteins; Mice; Mitochondria; Mitochondrial Proteins; Molecular Sequence Data; Pancreatic Neoplasms; Real-Time Polymerase Chain Reaction; Response Elements; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sequence Homology, Amino Acid

Pancreatic cancer is a highly lethal disease and gemcitabine is considered to be the standard of care for the treatment of advanced pancreatic cancer. However, the outcome of the patients treated with gemcitabine is still unstatisfactory and further development of new treatments is required. We recently found that short wavelength ultra-violet (UV-C) suppresses cell proliferation with downregulation of epidermal growth factor receptor (EGFR) in human pancreatic cancer cells, but not in normal pancreatic epithelial (PE) cells. In this study, we investigated the effect of UV-C on apoptosis in several cell lines derived from the pancreas. UV-C induced poly(ADP-ribose) polymerase (PARP) cleavage, which is a marker of cells undergoing apoptosis, in Panc1, MiaPaca2, KP3 and BxPC3 pancreatic cancer cells, but not in PE cells. We also observed similar effects in Hoechst 33258 staining, which shows DNA fragmentation. While p53, a tumor suppressor protein, plays a critical role in UV-C-induced cell damage, we did not observe the correlation between the sensitivity to UV-C and p53 status. Thapsigargin, an agent that promotes endoplasmic reticulum (ER) stress by depletion of lumenal calcium stores, as well as cis-diamineplatinum (II) dichloride, a classical anti-cancer drug that causes DNA damage, induced PARP cleavage even in PE cells. Moreover, UV-C-induced apoptosis in Panc1 and KP3 cells was associated with the release of cytochrome c, indicating that it was mediated via mitochondrial pathway. Taken together, UV-C has a potent anti-cancer effect on pancreatic cancer cells without adverse effect on normal cells and it could be useful for the treatment of human pancreatic cancers.

Topics: Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cisplatin; Cytochromes c; DNA Fragmentation; Enzyme Inhibitors; Epithelial Cells; Humans; Mitochondria; Pancreas; Pancreatic Neoplasms; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Signal Transduction; Thapsigargin; Tumor Suppressor Protein p53; Ultraviolet Rays

The aim of this study was to investigate induction of apoptosis by the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and gemcitabine in the pancreatic cancer cell line SW1990. The sensitivity of SW1990 cells to TRAIL and/or gemcitabine-induced apoptosis and the rate of apoptosis were assessed by MTT assay and flow cytometry, respectively. We used Hoechst 33342 staining to observe apoptotic morphology and expression levels of proteins were analyzed by Western blottin. Growth inhibition and apoptosis rates on treatment with the combination of TRAIL and gemcitabine were significantly higher than with each drug alone (p<0.05). Pancreatic cancer cells exhibited a typical apoptosis morphology after treatment with TRAIL or gemcitabine. The levels of cellular apoptosis-associated proteins such as Smac/DIABLO, Cyto C, and the activated fragment of caspase-3 (P17) increased, but the expression of XIAP was significantly decreased after 24 h (p<0.05). SW1990 cells responded to TRAIL and/or gemcitabine-induction of apoptosis in a time and concentration-dependent manner. The mechanism of the apoptosis-sensitization effect appeared associated with significant up-regulation of Smac/DIABLO and cytochrome C, down-regulation of XIAP, and activation of caspase-3.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Caspase 3; Cell Line, Tumor; Cell Proliferation; Cytochromes c; Deoxycytidine; Down-Regulation; Gemcitabine; Humans; Intracellular Signaling Peptides and Proteins; Mitochondrial Proteins; Pancreatic Neoplasms; TNF-Related Apoptosis-Inducing Ligand; Up-Regulation; X-Linked Inhibitor of Apoptosis Protein

Rottlerin is a polyphenolic compound derived from Mallotus philipinensis. In the present study, we show that rottlerin decreased tumor size and stimulated apoptosis in an orthotopic model of pancreatic cancer with no effect on normal tissues in vivo. Rottlerin also induced apoptosis in pancreatic cancer (PaCa) cell lines by interacting with mitochondria and stimulating cytochrome c release. Immunoprecipitation results indicated that rottlerin disrupts complexes of prosurvival Bcl-xL with Bim and Puma. Furthermore, siRNA knockdown showed that Bim and Puma are necessary for rottlerin to stimulate apoptosis. We also showed that rottlerin and Bcl-2 and Bcl-xL inhibitor BH3I-2' stimulate apoptosis through a common mechanism. They both directly interact with mitochondria, causing increased cytochrome c release and mitochondrial depolarization, and both decrease sequestration of BH3-only proteins by Bcl-xL. However, the effects of rottlerin and BH3I-2' on the complex formation between Bcl-xL and BH3-only proteins are different. BH3I-2' disrupts complexes of Bcl-xL with Bad but not with Bim or Puma, whereas rottlerin had no effect on the Bcl-xL interaction with Bad. Also BH3I-2', but not rottlerin, required Bad to stimulate apoptosis. In conclusion, our results demonstrate that rottlerin has a potent proapoptotic and antitumor activity in pancreatic cancer, which is mediated by disrupting the interaction between prosurvival Bcl-2 proteins and proapoptotic BH3-only proteins. Thus rottlerin represents a promising novel agent for pancreatic cancer treatment.

Topics: Acetophenones; Adenocarcinoma; Animals; Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Bcl-2-Like Protein 11; bcl-Associated Death Protein; bcl-X Protein; Benzamides; Benzopyrans; Cell Line, Tumor; Cytochromes c; Disease Models, Animal; Enzyme Inhibitors; Humans; Membrane Proteins; Mice; Mice, Nude; Mitochondria; Neoplasm Transplantation; Pancreatic Neoplasms; Protein Kinase C-delta; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Tumor Suppressor Proteins; Xenograft Model Antitumor Assays

Small heterodimer partner (SHP) is an epigenetically regulated nuclear transcriptional repressor that suppresses the development of liver cancer by inhibiting cellular growth. Here we report a novel cytoplasmic function of SHP through its regulation of mitochondrial activity. SHP is a pivotal cell death receptor that targets mitochondria, where it binds with Bcl-2, disrupts Bcl-2/Bid interaction, and induces cytochrome c release. The apoptosis inducer AHPN {retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid} acts by regulating SHP gene expression and promotes the translocation of SHP from the nucleus to the mitochondria. Induction of apoptosis by SHP activation inhibits peritoneal pancreatic tumor growth. Our findings provide for the first time a mechanism by which SHP regulates cell survival, namely, by controlling mitochondrial function via modulating the activity of Bcl-2 through AHPN-mediated or AHPN-independent action. Thus, SHP regulates a mechanism by which apoptotic signals can mediate local control of mitochondrial function and apoptosis, which in turn may limit tumorigenesis.

Topics: Adamantane; Animals; Apoptosis; Cell Nucleus; Cell Proliferation; Cell Respiration; Cinnamates; Cytochromes c; Fibroblasts; Gene Deletion; Gene Expression Regulation; Hepatocyte Nuclear Factor 4; Hepatocytes; Mice; Mitochondria; Pancreatic Neoplasms; Protein Binding; Protein Stability; Protein Transport; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Receptors, Cytoplasmic and Nuclear; Receptors, Death Domain; Retinoids; Signal Transduction

Prosurvival Bcl-2 proteins inhibit the mitochondrial and death receptor-mediated apoptotic pathways. Obatoclax is a small-molecule antagonist of the BH3-binding groove of Bcl-2 proteins that may enhance tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) sensitivity and efficacy.. Human pancreatic cancer cell lines were incubated with obatoclax and/or TRAIL and cell viability, Annexin V labeling, caspase cleavage, and cytochrome c release were measured. In drug-treated cell lines, protein-protein interactions were studied by immunoprecipitation. Bax/Bak activation was analyzed using conformation-specific antibodies. Lentiviral short hairpin RNA was used to knockdown Bim, Bid, and apoptosis-inducing factor (AIF) expression.. Obatoclax reduced the viability of PANC-1 and BxPC-3 cell lines and synergistically enhanced TRAIL-mediated cytotoxicity. Obatoclax enhanced TRAIL-mediated apoptosis, as shown by Annexin V labeling, which was accompanied by caspase activation (caspase-8, -9, and -3) and cleavage of Bid. Obatoclax potentiated TRAIL-mediated Bax/Bak activation and the release of mitochondrial cytochrome c, Smac, and AIF. Mechanisms underlying the apoptotic effect of obatoclax include displacement of Bak from its sequestration by Bcl-x(L) or Mcl-1 and release of Bim from Bcl-2 or Mcl-1. Bid knockdown by short hairpin RNA attenuated caspase cleavage and cytotoxicity of obatoclax plus TRAIL. Bim knockdown failed to inhibit the cytotoxic effect of obatoclax alone or combined with TRAIL yet attenuated TRAIL-mediated cytotoxicity. AIF knockdown attenuated cytotoxicity of the drug combination.. Obatoclax potentiates TRAIL-mediated apoptosis by unsequestering Bak and Bim from Bcl-2/Bcl-x(L) or Mcl-1 proteins. This drug combination enhances Bid-mediated cross-talk between the mitochondrial and death receptor-mediated apoptotic pathways and may represent a novel therapeutic strategy against pancreatic cancer.

Topics: Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; BH3 Interacting Domain Death Agonist Protein; Caspases; Cell Line, Tumor; Cytochromes c; Humans; Indoles; Myeloid Cell Leukemia Sequence 1 Protein; Pancreatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Pyrroles; TNF-Related Apoptosis-Inducing Ligand

Clinical management of pancreatic cancer is a major problem, which is in part due to both de novo and acquired resistance to conventional therapeutics. Here, we present in vitro and in vivo preclinical evidence in support of chemosensitization of pancreatic cancer cells by 3,3-diindolylmethane (DIM), a natural compound that can be easily obtained by consuming cruciferous vegetables. DIM pretreatment of pancreatic cancer cells led to a significantly increased apoptosis (P < 0.01) with suboptimal concentrations of chemotherapeutic agents (cisplatin, gemcitabine, and oxaliplatin) compared with monotherapy. It is known that resistance to chemotherapy in pancreatic cancer is associated with constitutively activated nuclear factor-kappaB (NF-kappaB), which becomes further activated by chemotherapeutic drugs. Our data provide mechanistic evidence for the first time showing that DIM potentiates the killing of pancreatic cancer cells by down-regulation of constitutive as well as drug-induced activation of NF-kappaB and its downstream genes (Bcl-xL, XIAP, cIAP, and survivin). Most importantly, using an orthotopic animal model, we found reduction in tumor size (P < 0.001) when DIM was given in combination with oxaliplatin compared with monotherapy. This was accompanied by loss of phospho-p65 and down-regulation of NF-kappaB activity and its downstream genes (Bcl-xL, survivin, and XIAP), which correlated with reduced cell proliferation (as assessed by Ki-67 immunostaining of tumor specimens) and evidence of apoptosis [as assessed by poly(ADP-ribose) polymerase cleavage and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining]. These results provide strong in vivo evidence in support of our hypothesis that DIM could abrogate chemotherapeutic drug (cisplatin, gemcitabine, and/or oxaliplatin)-induced activation of NF-kappaB, resulting in the chemosensitization of pancreatic tumors to conventional therapeutics.

Topics: Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Survival; Cisplatin; Cytochromes c; Deoxycytidine; Drug Synergism; Gemcitabine; Humans; Indoles; NF-kappa B; Organoplatinum Compounds; Oxaliplatin; Pancreatic Neoplasms

Previous studies have shown biological activity of thymoquinone, an active compound extracted from Nigella sativa, in pancreatic cancer cells; however, preclinical animal studies are lacking. Here, we report, for the first time, the chemosensitizing effect of thymoquinone to conventional chemotherapeutic agents both in vitro and in vivo using an orthotopic model of pancreatic cancer. In vitro studies revealed that preexposure of cells with thymoquinone (25 mumol/L) for 48 h followed by gemcitabine or oxaliplatin resulted in 60% to 80% growth inhibition compared with 15% to 25% when gemcitabine or oxaliplatin was used alone. Moreover, we found that thymoquinone could potentiate the killing of pancreatic cancer cells induced by chemotherapeutic agents by down-regulation of nuclear factor-kappaB (NF-kappaB), Bcl-2 family, and NF-kappaB-dependent antiapoptotic genes (X-linked inhibitors of apoptosis, survivin, and cyclooxygenase-2). As shown previously by our laboratory, NF-kappaB gets activated on exposure of pancreatic cancer cells to conventional chemotherapeutic agents; interestingly, thymoquinone was able to down-regulate NF-kappaB in vitro, resulting in chemosensitization. In addition to in vitro results, here we show for the first time, that thymoquinone in combination with gemcitabine and/or oxaliplatin is much more effective as an antitumor agent compared with either agent alone. Most importantly, our data also showed that a specific target, such as NF-kappaB, was inactivated in animal tumors pretreated with thymoquinone followed by gemcitabine and/or oxaliplatin. These results provide strong in vivo molecular evidence in support of our hypothesis that thymoquinone could abrogate gemcitabine- or oxaliplatin-induced activation of NF-kappaB, resulting in the chemosensitization of pancreatic tumors to conventional therapeutics.

Topics: Animals; Antineoplastic Agents; Apoptosis; Benzoquinones; Caspases; Cell Cycle; Cell Division; Cell Line, Tumor; Cell Survival; Cytochromes c; Deoxycytidine; Dinoprostone; Drug Synergism; Female; Gemcitabine; Humans; Mice; Mice, Inbred ICR; Mice, SCID; NF-kappa B; Organoplatinum Compounds; Oxaliplatin; Pancreatic Neoplasms

To determine the effect of ellagic acid on apoptosis and proliferation in pancreatic cancer cells and to determine the mechanism of the pro-survival effects of ellagic acid.. The effect of ellagic acid on apoptosis was assessed by measuring phosphatidylserine externalization, caspase activity, mitochondrial membrane potential and DNA fragmentation; and proliferation by measuring DNA thymidine incorporation. Mitochondrial membrane potential was measured in permeabilized cells, and in isolated mitochondria. Nuclear factor kappa B (NF-kappa B) activity was measured by electromobility shift assay (EMSA).. We show that ellagic acid, a polyphenolic compound in fruits and berries, at concentrations 10 to 50 mmol/L stimulates apoptosis in human pancreatic adenocarcinoma cells. Further, ellagic acid decreases proliferation by up to 20-fold at 50 mmol/L. Ellagic acid stimulates the mitochondrial pathway of apoptosis associated with mitochondrial depolarization, cytochrome C release, and the downstream caspase activation. Ellagic acid does not directly affect mitochondria. Ellagic acid dose-dependently decreased NF-kappa B binding activity. Furthermore, inhibition of NF-kappa B activity using IkB wild type plasmid prevented the effect of ellagic acid on apoptosis.. Our data indicate that ellagic acid stimulates apoptosis through inhibition of the prosurvival transcription factor NF-kappa B.

Topics: Adenocarcinoma; Antineoplastic Agents, Phytogenic; Apoptosis; Caspases; Cell Line, Tumor; Cell Proliferation; Cytochromes c; Dose-Response Relationship, Drug; Ellagic Acid; Humans; I-kappa B Proteins; Membrane Potential, Mitochondrial; Mitochondria; NF-kappa B; Pancreatic Neoplasms

1,1-Bis(3'-indolyl)-1-(p-substituted phenyl)methanes, containing p-t-butyl (DIM-C-pPhtBu) and phenyl (DIM-C-pPhC(6)H(5)) substituents, are peroxisome proliferator-activated receptor gamma (PPARgamma) agonists; however, DIM-C-pPhtBu-induced growth inhibition and cell death in human HEC1A endometrial cancer cells is PPARgamma-independent. DIM-C-pPhtBu decreased mitochondrial membrane potential (MMP) and promoted the release of cytochrome c and caspase activation and nuclear uptake of endonuclease G leading to apoptosis of HEC1A cells. DIM-C-pPhtBu specifically targeted the mitochondrial permeability transition pore complex (PTPC) because the DIM-C-pPhtBu-induced pro-apoptotic responses were inhibited by atractyloside (Atra), a compound that specifically interacts with the inner mitochondrial membrane adenine nucleotide transport (ANT) proteins. At the dose of Atra used in this study (300 microM), this compound alone did not alter the PTPC but inhibited the mitochondriotoxic effects of DIM-C-pPhtBu. DIM-C-pPhtBu/DIM-C-pPhC(6)H(5) and Atra also differentially affected the ability of eosin-5-maleimide (EMA) to alkylate Cys160 in the ANT protein and Atra, but not DIM-C-pPhtBu, inhibited the exchange of ATP/ADP in isolated mitochondria suggesting that these pharmacophores act on different sites on the ANT protein. Results of this study show that the receptor-independent proapoptotic activity of DIM-C-pPhtBu and DIM-C-pPhC(6)H(5) were related to novel mitochondriotoxic activities involving inner mitochondrial ANT proteins.

Topics: Adenine Nucleotide Translocator 1; Adenosine Triphosphate; Alkylation; Apoptosis; Atractyloside; Blotting, Northern; Blotting, Western; Caspases; Cell Proliferation; Cytochromes c; Endometrial Neoplasms; Enzyme Activation; Enzyme-Linked Immunosorbent Assay; Female; Fluorescent Antibody Technique; Humans; Indoles; Membrane Potential, Mitochondrial; Pancreatic Neoplasms; PPAR gamma; Reverse Transcriptase Polymerase Chain Reaction; Tumor Cells, Cultured

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a promising candidate for cancer therapy because of its relative tumor selectivity. However, many cancers including pancreatic cancer remain resistant towards TRAIL. To develop TRAIL for cancer therapy of pancreatic carcinoma, it will therefore be pivotal to elucidate the molecular mechanisms of TRAIL resistance. Here, we identify X-linked inhibitor of apoptosis (XIAP) as a regulator of TRAIL sensitivity in pancreatic carcinoma cells. Full activation of effector caspases, loss of mitochondrial membrane potential and cytochrome c release following TRAIL treatment were markedly impaired in pancreatic carcinoma cell lines, which poorly responded to TRAIL (PaTuII, PancTu1, ASPC1, DanG), compared to TRAIL-sensitive Colo357 pancreatic carcinoma cells. Stable downregulation of XIAP by RNA interference significantly reduced survival and enhanced TRAIL-induced apoptosis in pancreatic carcinoma cells. Also, downregulation of XIAP significantly increased CD95-induced cell death. Importantly, knockdown of XIAP strongly inhibited clonogenicity of pancreatic cancer cells treated with TRAIL indicating that XIAP promotes clonogenic survival of pancreatic carcinoma cells. Thus, our findings for the first time indicate that targeting XIAP represents a promising strategy to enhance the antitumor activity of TRAIL in pancreatic cancer, which has important clinical implications.

Topics: Apoptosis; Caspases, Effector; Cytochromes c; Humans; Ligands; Membrane Potential, Mitochondrial; Pancreatic Neoplasms; Receptors, TNF-Related Apoptosis-Inducing Ligand; Retroviridae; TNF-Related Apoptosis-Inducing Ligand; Transfection; Tumor Cells, Cultured; Tumor Stem Cell Assay; X-Linked Inhibitor of Apoptosis Protein

We have previously shown that the leukotriene B4 receptor antagonist, LY293111 inhibits proliferation and induces apoptosis in human pancreatic cancer cells both in vitro and in vivo. In the current study, we investigated the molecular mechanisms of LY293111-induced apoptosis and cell cycle arrest. Two human pancreatic cancer cell lines were used in this study, MiaPaCa-2 and AsPC-1. Cell cycle analysis by flow cytometry showed a dramatic increase in the percentage of apoptotic cells as well as S-phase arrest after treatment with 250 nmol/l LY293111 for up to 48 h. Western blotting indicated that LY293111 treatment induced cytochrome c release from the mitochondria into the cytosol, accompanied by caspase-9, caspase-7 and caspase-3 activation, and cleavage of poly ADP-ribose polymerase. Caspase-8 was not activated by LY293111. A decrease was found in the expression of the antiapoptotic proteins, Bcl-2 and Mcl-1, and an increase in the proapoptotic protein, Bax. LY293111 reduced the expression of CDK2, cyclin A and cyclin E, consistent with the S-phase arrest observed in these cells. The expression of cyclin-dependent kinase inhibitors, p21 and p27 was not affected by LY293111 treatment. In conclusion, LY293111 induces apoptosis in human pancreatic cancer cells through the mitochondria-mediated pathway. LY293111 also induces S-phase arrest with downregulation of CDK2, cyclin A and cyclin E. Blockade of leukotriene B4 metabolic pathway may provide a novel treatment for human pancreatic cancer.

Topics: Apoptosis; bcl-2-Associated X Protein; Benzoates; Blotting, Western; Caspase 3; Caspase 7; Caspase 9; Cell Cycle; Cell Line, Tumor; Cyclin A; Cyclin E; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Cytochromes c; Enzyme Activation; Flow Cytometry; Genes, bcl-2; Humans; Leukotriene Antagonists; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasm Proteins; Pancreatic Neoplasms; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; Receptors, Leukotriene B4; S Phase

Pancreatic cancer is highly resistant to current chemotherapy agents. We therefore examined the effects of triptolide (a diterpenoid triepoxide) on pancreatic cancer growth and local-regional tumor spread using an orthotopic model of pancreatic cancer. We have recently shown that an increased level of HSP70 in pancreatic cancer cells confers resistance to apoptosis and that inhibiting HSP70 induces apoptosis in these cells. In addition, triptolide was recently identified as part of a small molecule screen, as a regulator of the human heat shock response. Therefore, our aims were to examine the effects of triptolide on (a) pancreatic cancer cells by assessing viability and apoptosis, (b) pancreatic cancer growth and local invasion in vivo, and (c) HSP70 levels in pancreatic cancer cells. Incubation of PANC-1 and MiaPaCa-2 cells with triptolide (50-200 nmol/L) significantly reduced cell viability, but had no effect on the viability of normal pancreatic ductal cells. Triptolide induced apoptosis (assessed by Annexin V, caspase-3, and terminal nucleotidyl transferase-mediated nick end labeling) and decreased HSP70 mRNA and protein levels in both cell lines. Triptolide (0.2 mg/kg/d for 60 days) administered in vivo decreased pancreatic cancer growth and significantly decreased local-regional tumor spread. The control group of mice had extensive local invasion into adjacent organs, including the spleen, liver, kidney, and small intestine. Triptolide causes pancreatic cancer cell death in vitro and in vivo by induction of apoptosis and its mechanism of action is mediated via the inhibition of HSP70. Triptolide is a potential therapeutic agent that can be used to prevent the progression and metastases of pancreatic cancer.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Caspase 3; Cell Growth Processes; Cell Line, Tumor; Cytochromes c; Diterpenes; Epoxy Compounds; HSP70 Heat-Shock Proteins; Humans; Mice; Mice, Nude; Pancreatic Neoplasms; Phenanthrenes; Xenograft Model Antitumor Assays

PS-341 (bortezomib) is a potent and reversible proteosome inhibitor that functions to degrade intracellular polyubiquitinated proteins. PS-341 induces apoptosis and has shown broad antitumor activity with selectivity for transformed cells. We studied the effect of PS-341 on lysosomal and mitochondrial permeabilization, including the role of caspase-2 activation in apoptosis induction in the BxPC-3 human pancreatic carcinoma cell line. PS-341 induced a dose-dependent apoptosis in association with reactive oxygen species generation and cleavage of caspase-2 to its 33- and 14-kDa fragments. PS-341 disrupted lysosomes with redistribution of cathepsin B to the cytosol, as shown using fluorescence confocal microscopy, that was blocked by the free radical scavenger tiron but not by a caspase-2 inhibitor (benzyloxycarbonyl (Z)-VDVAD-fluoromethyl ketone (FMK)). PS-341-induced caspase-2 activation was attenuated by a selective pharmacological inhibitor of cathepsin B (R-3032), suggesting that cathepsin B release occurs upstream of caspase-2. PS-341-induced mitochondrial depolarization was attenuated by Z-VDVAD-FMK, tiron, and an inhibitor of the mitochondrial permeability transition pore (bongkrekic acid). Regulation of mitochondrial permeability by caspase-2 was confirmed using caspase-2 small interfering RNA. PS-341-induced cytochrome c release and phosphatidylserine externalization were attenuated by Z-VDVAD-FMK and partially by R-3032. PS-341 activated the BH3-only proteins Bik and Bim and down-regulated Bcl-2 and Bcl-xL mRNA and protein expression. Taken together, PS-341 induces lysosomal cathepsin B redistribution upstream of caspase-2. Caspase-2 activation regulates PS-341-induced mitochondrial depolarization and apoptosis, suggesting that caspase-2 can serve as a link between lysosomal and mitochondrial permeabilization.

Topics: Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Bcl-2-Like Protein 11; bcl-X Protein; Boronic Acids; Bortezomib; Caspase 2; Cathepsin B; Cysteine Endopeptidases; Cytochromes c; Down-Regulation; Enzyme Inhibitors; Humans; Lysosomes; Membrane Proteins; Mitochondrial Membranes; Mitochondrial Proteins; Pancreatic Neoplasms; Permeability; Phosphatidylserines; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Pyrazines; Reactive Oxygen Species; RNA, Messenger; Tumor Cells, Cultured

Polyphenols such as epigallocatechin-3-gallate (EGCG) from green tea extract can exert a growth-suppressive effect on human pancreatic cancer cells in vitro. In pursuit of our investigations to dissect the molecular mechanism of EGCG action on pancreatic cancer, we observed that the antiproliferative action of EGCG on pancreatic carcinoma is mediated through programmed cell death or apoptosis as evident from nuclear condensation, caspase-3 activation and poly-ADP ribose polymerase (PARP) cleavage. EGCG-induced apoptosis of pancreatic cancer cells is accompanied by growth arrest at an earlier phase of the cell cycle. In addition, EGCG invokes Bax oligomerization and depolarization of mitochondrial membranes to facilitate cytochrome c release into cytosol. EGCG-induced downregulation of IAP family member X chromosome linked inhibitor of apoptosis protein (XIAP) might be helpful to facilitate cytochrome c mediated downstream caspase activation. On the other end, EGCG elicited the production of intracellular reactive oxygen species (ROS), as well as the c-Jun N-terminal kinase (JNK) activation in pancreatic carcinoma cells. Interestingly, inhibitor of JNK signaling pathway as well as antioxidant N-acetyl-L-cysteine (NAC) blocked EGCG-induced apoptosis. To summarize, our studies suggest that EGCG induces stress signals by damaging mitochondria and ROS-mediated JNK activation in MIA PaCa-2 pancreatic carcinoma cells.

Topics: Antioxidants; Apoptosis; Caspases; Catechin; Cell Proliferation; Cytochromes c; Cytosol; G2 Phase; Humans; JNK Mitogen-Activated Protein Kinases; Membrane Potentials; Mitochondria; Pancreatic Neoplasms; Signal Transduction; Tea

Pancreatic cancer is characterised by a highly malignant phenotype with a marked resistance to conventional therapies and to apoptotic activators. Here, we demonstrate that sodium butyrate (NaBt), an inhibitor of histone deacetylases, sensitises human pancreatic cancer cell lines to both mitochondria- and Fas-mediated apoptosis. The analysis of anti-apoptotic and pro-apoptotic members of the Bcl-2 family in untreated pancreatic cancer cell lines shows a generalised low expression of Bcl-2 and a strong expression of Bcl-xL. NaBt treatment results in a marked down-regulation of Bcl-xL expression, mitochondrial membrane depolarization, cytochrome c release from mitochondria, activation of caspase-9 and -3 and apoptosis induction. Furthermore, NaBt sensitises pancreatic cancer cells to Fas-mediated apoptosis as well. In fact, the combined treatment with NaBt and the agonistic antibody anti-Fas (CH11) is able to induce apoptosis at an early time, in which neither NaBt nor CH11 alone induce apoptosis. Down-regulation of FLIP and activation of caspase-8 allow apoptosis to occur. These findings suggest that sodium butyrate could represent a good candidate for the development of new therapeutic strategies aimed at improving chemotherapy and immunotherapy in pancreatic cancer.

Topics: Apoptosis; bcl-X Protein; Blotting, Western; Butyrates; Caspases; Cell Line, Tumor; Cytochromes c; DNA Primers; Flow Cytometry; Fluorescent Antibody Technique; Gene Expression Regulation, Neoplastic; Humans; Mitochondrial Membranes; Pancreatic Neoplasms; Polymerase Chain Reaction; Proto-Oncogene Proteins c-bcl-2; Tetrazolium Salts; Thiazoles

In pancreatic cancer, several important survival molecules such as EGFR, NF-kappaB, and Bcl-2 or Bcl-XL are highly activated. Thus, agents that inhibit NF-kappaB activation, together with agents that directly inhibit Bcl-2 or Bcl-XL protein function, may lead to enhanced cell killing. (-)-Gossypol, a natural polyphenolic compound isolated from cottonseeds, is a dual and potent small-molecule inhibitor of Bcl-2 and Bcl-XL proteins, with a Ki value in the 300-600 nM range for both proteins.. : The BxPC-3 human pancreatic cell line was used in this study. (-)-Gossypol was dissolved in DMSO at 20 mmol/L as stock solution, and genistein was dissolved in 0.1 M Na2CO3 to make a 10 mM stock solution. For cell viability, apoptosis, and NF-kappaB studies, MTT assay, histone/DNA ELISA, and Electrophoretic Mobility Shift Assay (EMSA) were used, respectively. Coimmunoprecipitation experiments were designed to study Bcl-XL/Bim heterodimerization, and Western blots to study cytochrome c release.. (-)-Gossypol showed a concentration-dependent growth inhibition effect against BxPC-3 pancreatic cancer cell line and induced apoptosis with no effect on normal peripheral blood lymphocytes. Results from coimmunoprecipitation experiments indicate that the effect of (-)-gossypol is mediated, at least, in part via disrupting the heterodimerization of Bcl-XL with Bim in BxPC-3 pancreatic cancer cells. (-)-Gossypol completely disrupts Bcl-XL/Bim heterodimerization with no change in the total Bcl-XL or Bim protein, indicating that (-)-gossypol treatment does not affect the levels of Bcl-XL and Bim proteins. We have previously shown that genistein, a prominent soy isoflavone, transcriptionally down-regulates Bcl-2, Bcl-XL, VEGF, MMP-9, and uPAR via inhibiting NF-kappaB activity. In this study, genistein down-regulated NF-kappaB DNA binding activity and inhibited the growth of BxPC-3 pancreatic cancer cells. In addition, the combination of (-)-gossypol with genistein showed significantly greater growth inhibition compared with either agent alone.. From these results, we conclude that inhibition of NF-kappaB activity and direct inhibition of Bcl-2 or Bcl-XL function should serve as a novel strategy for pancreatic cancer therapy.

Topics: Apoptosis; bcl-X Protein; Cell Line, Tumor; Cytochromes c; Drug Synergism; Genistein; Gossypol; Humans; NF-kappa B; Pancreatic Neoplasms; Proto-Oncogene Proteins c-bcl-2

Bortezomib (PS-341, Velcade) is a potent and selective inhibitor of the proteasome that is currently under investigation for the treatment of solid malignancies. We have shown previously that bortezomib has activity in pancreatic cancer models and that the drug induces endoplasmic reticulum (ER) stress but also suppresses the unfolded protein response (UPR). Because the UPR is an important cytoprotective mechanism, we hypothesized that bortezomib would sensitize pancreatic cancer cells to ER stress-mediated apoptosis. Here, we show that bortezomib promotes apoptosis triggered by classic ER stress inducers (tunicamycin and thapsigargin) via a c-Jun NH(2)-terminal kinase (JNK)-dependent mechanism. We also show that cisplatin stimulates ER stress and interacts with bortezomib to increase ER dilation, intracellular Ca(2+) levels, and cell death. Importantly, combined therapy with bortezomib plus cisplatin induced JNK activation and apoptosis in orthotopic pancreatic tumors resulting in a reduction in tumor burden. Taken together, our data establish that bortezomib sensitizes pancreatic cancer cells to ER stress-induced apoptosis and show that bortezomib strongly enhances the anticancer activity of cisplatin.

Topics: Animals; Anti-Bacterial Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Boronic Acids; Bortezomib; Calcium; Carcinogens; Caspase Inhibitors; Caspases; Cell Line, Tumor; Cisplatin; Cytochromes c; Drug Interactions; Endoplasmic Reticulum; Enzyme Activation; Humans; Immunoblotting; JNK Mitogen-Activated Protein Kinases; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Pancreatic Neoplasms; Pyrazines; RNA, Small Interfering; Thapsigargin; Tumor Stem Cell Assay; Tunicamycin

To study the effect of red oil A5 on pancreatic cancer cells and its possible mechanisms.. Effect of different concentrations of red oil A5 on proliferation of three pancreatic cancer cell lines, AsPC-1, MiaPaCa-2 and S2013, was measured by (3)H-methyl thymidine incorporation. Time-dependent effects of 1:32 000 red oil A5 on proliferation of three pancreatic cancer cell lines, were also measured by (3)H-methyl thymidine incorporation, and Time-course effects of 1:32 000 red oil A5 on cell number. The cells were counted by Z1-Coulter Counter. Flow-cytometric analysis of cellular DNA content in the control and red oil A5 treated AsPC-1, MiaPaCa-2 and S2013 cells, were stained with propidium iodide. TUNEL assay of red oil A5-induced pancreatic cancer cell apoptosis was performed. Western blotting of the cytochrome c protein in AsPC-1, MiaPaCa-2 and S2013 cells treated 24 hours with 1:32 000 red oil A5 was performed. Proteins in cytosolic fraction and in mitochondria fraction were extracted. Proteins extracted from each sample were electrophoresed on SDS-PAGE gels and then were transferred to nitrocellulose membranes. Cytochrome c was identified using a monoclonal cytochrome c antibody. Western blotting of the caspase-3 protein in AsPC-1, MiaPaCa-2 and S2013 cells treated with 1:32 000 red oil A5 for 24 hours was carried out. Proteins in whole cellular lysates were electrophoresed on SDS-PAGE gels and then transferred to nitrocellulose membranes. Caspase-3 was identified using a specific antibody. Western blotting of poly-ADP ribose polymerase (PARP) protein in AsPC-1, MiaPaCa-2 and S2013 cells treated with 1:32 000 red oil A5 for 24 hours was performed. Proteins in whole cellular lysates were separated by electrophoresis on SDS-PAGE gels and then transferred to nitrocellulose membranes. PARP was identified by using a monoclonal antibody.. Red oil A5 caused dose- and time-dependent inhibition of pancreatic cancer cell proliferation. Propidium iodide DNA staining showed an increase of the sub-G0/G1 cell population. The DNA fragmentation induced by red oil A5 in these three cell lines was confirmed by the TUNEL assay. Furthermore, Western blotting analysis indicated that cytochrome c was released from mitochondria to cytosol during apoptosis, and caspase-3 was activated following red oil A5 treatment which was measured by procaspase-3 cleavage and PARP cleavage.. These findings show that red oil A5 has potent anti-proliferative effects on human pancreatic cancer cells with induction of apoptosis in vitro.

Topics: Apoptosis; Caspase 3; Caspases; Cell Count; Cell Division; Cell Line, Tumor; Cytochromes c; Fish Oils; Humans; Pancreatic Neoplasms; Poly(ADP-ribose) Polymerases; Thymidine

Palliative chemotherapy with gemcitabine, a common mode of treatment of pancreatic cancer, has little influence on patients' survival. We investigated the impact of anti-apoptotic Bcl-xL protein and its antagonist Bax on gemcitabine-induced apoptosis in human pancreatic carcinoma cells in vitro and in vivo. The level of Bcl-xL and Bax expression was determined in 3 established pancreatic cancer cell lines that differ in their sensitivity to gemcitabine-mediated apoptosis. Bcl-xL and Bax genes were transduced into Colo357 cells by retroviral infection. In addition, cells were transfected with c-FLIP to assess involvement of CD95 and caspase-8. The impact of Bax/Bcl-xL expression on gemcitabine-sensitivity in vivo was evaluated in orthotopic Colo357 tumors in SCID mice. The apoptotic index revealed a strong inverse correlation between Bcl-xL expression and gemcitabine-induced apoptosis in the pancreatic carcinoma cell lines tested. Caspase-8 and Bid were cleaved in Colo357 cells exposed to gemcitabine, and there was no correlation with either Bcl-xL or with Bax expression. In contrast, the lack of mitochondrial transmembrane potential transition, release of cytochrome-c and absence of caspase-9- and PARP-cleavage showed a strong correlation with Bcl-xL expression. Expression of c-FLIP significantly increased the resistance towards gemcitabine. Orthotopically growing Colo357-bcl-xl tumors in SCID mice were refractory to gemcitabine treatment, and in contrast to the in vitro data, Colo357-bax tumors exhibited a 12-fold greater tumor regression than Colo357-wild-type tumors in the control group. Gemcitabine-induced apoptosis involves the mitochondria-mediated signaling pathway. A functional restoration of this pathway appears to be essential to overcome the resistance mechanisms of pancreatic tumor cells and to improve the response to therapy as demonstrated by Bax overexpression in a clinically relevant tumor model.

Topics: Animals; Antimetabolites, Antineoplastic; Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; BH3 Interacting Domain Death Agonist Protein; Carrier Proteins; CASP8 and FADD-Like Apoptosis Regulating Protein; Caspase 8; Caspase 9; Caspases; Cytochromes c; Deoxycytidine; Drug Resistance, Neoplasm; fas Receptor; Female; Gemcitabine; Intracellular Signaling Peptides and Proteins; Membrane Potentials; Mice; Mice, Inbred BALB C; Mice, SCID; Mitochondria; Pancreatic Neoplasms; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Retroviridae; Tumor Cells, Cultured

Most patients with pancreatic adenocarcinoma present with surgically incurable disease. Gemcitabine, the principal agent used to treat such patients, has little impact on outcome. Overexpression of carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 6, a feature of this malignancy, is associated with resistance to anoikis and increased metastasis. The purpose of this study was to determine the role of CEACAM6 in cellular chemoresistance to gemcitabine. CEACAM6 was stably overexpressed in Capan2 cells, which inherently express very low levels of the protein. Suppression of CEACAM6 expression was achieved in BxPC3 cells, which inherently overexpress CEACAM6, by stable transfection of a CEACAM6 small interfering RNA-generating vector. The effects of modulating CEACAM6 expression on gemcitabine-induced cytotoxicity were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cytotoxicity assay, flow cytometric apoptosis quantification, caspase profiling, and Western analysis of cytoplasmic cytochrome c release. The roles of Akt and c-Src kinases as downstream targets of CEACAM6 signaling were examined. Stable overexpression of CEACAM6 in Capan2 increased gemcitabine chemoresistance, whereas CEACAM6 gene silencing in BxPC3 markedly increased the sensitivity of these cells to gemcitabine. Differential expression of CEACAM6 modulates Akt activity in a c-Src-dependent manner, and CEACAM6 overexpression appears to protect cells from cytochrome c-induced caspase 3 activation and apoptosis.

Topics: Adenocarcinoma; Antigens, CD; Antigens, Neoplasm; Antimetabolites, Antineoplastic; Caspase 3; Caspases; Cell Adhesion Molecules; Cell Line, Tumor; CSK Tyrosine-Protein Kinase; Cytochromes c; Deoxycytidine; Drug Resistance, Viral; Enzyme Activation; Gemcitabine; Gene Silencing; GPI-Linked Proteins; Humans; Pancreatic Neoplasms; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; src-Family Kinases; Transfection

quinone oxidoreductase (NQO(1)) catalyzes the two-electron reduction of quinones to hydroquinones. This reaction is believed to prevent the one-electron reduction of quinones that would result in redox cycling with generation of superoxide (O(2)(.-)). We have recently demonstrated that inhibition of NQO(1) with dicumarol increases intracellular O(2)(.-) production and inhibits the in vitro malignant phenotype of pancreatic cancer cells (J. Cullen et al., Cancer Res., 63: 5513-5520, 2003). We hypothesized that inhibition of NQO(1) would increase cell killing, induce oxidative stress, and inhibit in vivo tumor growth.. In the human pancreatic cancer cell line MIA PaCa-2, dicumarol decreased cell viability, as measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and decreased clonogenic survival. Dicumarol increased the percentage of apoptotic cells in a time-dependent and dose-dependent manner as measured by 3,3'-diaminobenzidine staining and flow cytometry, which was associated with cytochrome c release and poly(ADP-ribose) polymerase cleavage. Dicumarol also induced oxidative stress as evidenced by increased total glutathione and oxidized glutathione, as well as sensitizing to cell killing mediated by menadione. In established orthotopic pancreatic tumors in nude mice, intratumoral injections of dicumarol slowed tumor growth and extended survival.. Inhibition of NQO(1) with dicumarol induces cell killing and oxidative stress in pancreatic cancer cells and speculate that dicumarol may prove to be useful in pancreatic cancer therapeutics.

Topics: Animals; Apoptosis; Blotting, Western; Cell Line, Tumor; Cell Survival; Cytochromes c; Dicumarol; Dose-Response Relationship, Drug; Electrons; Enzyme Inhibitors; Flow Cytometry; Glutathione; Humans; Hydroquinones; Mice; Mice, Nude; NAD(P)H Dehydrogenase (Quinone); Oxidative Stress; Oxygen; Pancreatic Neoplasms; Phenotype; Poly(ADP-ribose) Polymerases; Quinone Reductases; Time Factors; Uncoupling Agents; Vitamin K 3