UNIPROT:P10415 - FACTA Search

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Query: UNIPROT:P10415 (Bcl-2)
33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The prognosis of advanced pancreatic cancer is poor. Established chemotherapy shows only limited efficacy and significant side effects. We investigated how far a combination of trichostatin A (TSA) and gemcitabine synergizes to inhibit proliferation and promotion of apoptosis of pancreatic adenocarcinoma cells in vitro. The human pancreatic carcinoma cells YAPC, DANG and Panc-89 and primary human foreskin fibroblasts as non-malignant controls were cultured under standardized conditions and incubated with gemcitabine und TSA alone (10(-4) to 10(-8) M) or together (10(-6) to 10(-7) M). After 24-72 h the apoptotic rate was analyzed by flow cytometry (propidium iodide, FACS). DNA-synthesis was assessed using bromodeoxyuridine (BrdU) incorporation. Protein was separated for Western blotting against caspase-3 and -8, p21, bax and bcl-2. The combination of TSA und gemcitabine leads to better pro-apoptotic effects than the employment of single substances. Bcl-2, a mitochondrial protein, which protects against apoptosis, was not expressed. Bax, an apoptosis inducing protein, which destabilizes the mitochondrial membrane potential, was increasingly expressed. Combination of TSA and gemcitabine shows promise for treatment of pancreatic cancer in vivo.
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PMID:The combination of the histone-deacetylase inhibitor trichostatin A and gemcitabine induces inhibition of proliferation and increased apoptosis in pancreatic carcinoma cells. 1767 83

Neuropilin-1 (Np-1) is a coreceptor for vascular endothelial growth factor-A (VEGF-A), and both are expressed at high levels in pancreatic ductal adenocarcinomas (PDACs). While VEGF-A has been implicated in tumor angiogenesis, the role of Np-1 in PDAC is less clearly defined. Accordingly, PANC-1 pancreatic cancer cells, which express relatively high levels of Np-1, were transfected with the Np-1 antisense cDNA. By comparison with sham transfected cells, Np-1 antisense expressing clones (Np-1AS) exhibited decreased anchorage independent growth, adhesion and invasiveness, and prolonged doubling times. Np-1AS were also more sensitive to the pro-apoptotic actions of ActD, as evidenced by PARP cleavage, caspase 9 activation and annexin V staining. ActD decreased Bcl-xL and STAT5 levels in the antisense expressing cells, but not in sham-transfected cells, and did not alter STAT3, Bcl-2, phospho-AKT, AKT, Bad, Bax or Bak levels. Immunoprecipitation followed by immunoblotting revealed that Np-1 associated with integrin beta1 and integrin beta1 blockade attenuated adhesion. However, Np-AS expressing clones exhibited enhanced tyrosine phosphorylated focal adhesion kinase. Thus, Np-1 confers a growth and survival advantage to PANC-1 cells, and interacts with integrin beta1 to coordinate signaling events that promote cell adherence and invasiveness.
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PMID:Neuropilin-1 interacts with integrin beta1 and modulates pancreatic cancer cell growth, survival and invasion. 1772 69

Human pancreatic tumor cells are highly resistant to both tumor necrosis factor (TNF) and to chemotherapeutic agents. HER-2/neu expression has been proposed as a negative prognostic marker in pancreatic intraepithelial neoplasia. Our approach was to utilize HER-2/neu expression on the surface of tumor cells as a therapeutic target employing scFv23/TNF, immunocytokine composed of a single chain Fv antibody (scFv23) targeting the HER-2/neu and the cytokine TNF as the cytotoxic moiety, to deliver TNF directly to TNF-resistant pancreatic tumor cells. Using a panel of human pancreatic cell lines, which overexpress HER-2/neu, we evaluated the in vitro response of cells to TNF, scFv23/TNF, Herceptin, and a combination of scFv23/TNF with various chemotherapeutic agents. We found that all pancreatic cancer cell lines were highly resistant to the cytotoxic effects of TNF and that scFv23/TNF was highly cytotoxic to TNF-resistant HER-2/neu-expressing pancreatic cancer cell lines at levels rivaling that of conventional chemotherapeutic agents. Combination studies demonstrated a synergistic cytotoxic effect of scFv23/TNF with 5-fluorouracil (5-FU) in TNF-resistant pancreatic cancer cell lines. Mechanistic studies demonstrated that the 5-FU plus scFv23/TNF combination specifically resulted in a down-regulation of HER-2/neu, p-Akt and Bcl-2 and up-regulation of TNF-R1. In addition, the combination 5-FU plus scFv23/TNF induced apoptosis and this synergistic effect was dependent on activation of caspase-8 and caspase-3. Delivery of the cytokine TNF to HER-2/neu expressing pancreatic tumor cells, which are inherently resistant to TNF using scFv23/TNF may be an effective therapy for pancreatic cancer especially when utilized in combination with 5-FU.
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PMID:The immunocytokine scFv23/TNF targeting HER-2/neu induces synergistic cytotoxic effects with 5-fluorouracil in TNF-resistant pancreatic cancer cell lines. 1808 72

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to induce mitochondrial apoptotic signaling that can be negatively regulated by prosurvival Bcl-2 proteins. ABT-737 is a small-molecule BH3 mimetic that binds to and antagonizes Bcl-2/Bcl-x(L) but not Mcl-1. We show that ABT-737 can synergistically enhance TRAIL-mediated cytotoxicity in human pancreatic cancer cell lines. ABT-737 was shown to enhance TRAIL-induced apoptosis as shown by DNA fragmentation, activation of caspase-8 and Bid, and cleavage of caspase-3 and poly(ADP-ribose) polymerase. A Bax conformational change induced by TRAIL was enhanced by ABT-737. ABT-737 disrupted the interaction of Bak with Bcl-x(L) in both cell lines. Furthermore, ABT-737 untethered the proapoptotic BH3-only protein Bim from its sequestration by Bcl-x(L) or Bcl-2. Bim small hairpin RNA (shRNA) was shown to attenuate caspase-3 cleavage and to reduce the cytotoxic effects of TRAIL plus ABT-737 compared with shRNA control cells. Finally, Mcl-1 shRNA potentiated caspase-3 cleavage by ABT-737 and enhanced its cytotoxic effects. Taken together, ABT-737 augments TRAIL-induced cell killing by unsequestering Bim and Bak and enhancing a Bax conformational change induced by TRAIL. These findings suggest a novel strategy to enhance cross-talk between the extrinsic and intrinsic apoptotic pathways to improve therapeutic efficacy against pancreatic cancer.
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PMID:BH3 mimetic ABT-737 potentiates TRAIL-mediated apoptotic signaling by unsequestering Bim and Bak in human pancreatic cancer cells. 1841 64

Bcl-2 family of proteins plays critical roles in human cancers, including pancreatic cancer, suggesting that the discovery of specific agents targeting Bcl-2 family proteins would be extremely valuable for pancreatic cancer therapy. We have previously reported the synthesis and characterization of TW-37, which seems to be a negative regulator of Bcl-2. In this investigation, we tested our hypothesis whether TW-37 could be an effective inhibitor of cell growth, invasion and angiogenesis in pancreatic cancer cells. Using multiple cellular and molecular approaches such as MTT assay, apoptosis enzyme-linked immunosorbent assay, real-time reverse transcription-polymerase chain reaction, Western blotting, electrophoretic mobility shift assay for measuring DNA binding activity of NF-kappaB, migration, invasion and angiogenesis assays, we found that TW-37, in nanomolar concentrations, inhibited cell growth in a dose- and time-dependent manner. This was accompanied by increased apoptosis and concomitant attenuation of NF-kappaB, and downregulation of NF-kappaB downstream genes such as MMP-9 and VEGF, resulting in the inhibition of pancreatic cancer cell migration, invasion and angiogenesis in vitro and caused antitumor activity in vivo. From these results, we conclude that TW-37 is a potent inhibitor of progression of pancreatic cancer cells, which could be due to attenuation of Bcl-2 cellular signaling processes. Our findings provide evidence showing that TW-37 could act as a small-molecule Bcl-2 inhibitor on well-characterized pancreatic cancer cells in culture as well as when grown as tumor in a xenograft model. We also suggest that TW-37 could be further developed as a potential therapeutic agent for the treatment of pancreatic cancer.
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PMID:TW-37, a small-molecule inhibitor of Bcl-2, inhibits cell growth and invasion in pancreatic cancer. 2753 21

Pancreatic cancer (PC) remains the fourth most common cause of cancer related death in the United States. Therefore, novel strategies for the prevention and treatment are urgently needed. Numerous dietary and pharmacological agents have been proposed as alternative strategies for the prevention and/or treatment of PC. Isoflavone is a prominent flavonoid found in soy products and has been proposed to be responsible for lowering the incidence of PC in Asians. Similarly, curcumin, an active ingredient of turmeric, that inhibits growth of malignant neoplasms, has a promising role in the prevention and/or treatment of PC. Here we examined whether isoflavone together with curcumin could elicit a greater inhibition of growth of PC cells than either agent alone, and also sought to determine the molecular mechanism of action. We found that the inhibition of cell growth and induction of apoptosis was significantly greater in the combination group than that could be achieved by either agent alone. These changes were associated with decreased Notch-1 expression and DNA binding activity of NF-kappaB and its target genes such as Cyclin D1, Bcl-2, and Bcl-xL. Moreover, we found that the combination of four natural agents at lower concentration was much more effective. Collectively, our results suggest that diet containing multiple natural products should be preferable over single agents for the prevention and/or treatment of PC. The superior effects of the combinatorial treatment could partly be attributed to the inhibition of constitutive activation of Notch-1 and NF-kappaB signaling pathways.
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PMID:Synergistic effects of multiple natural products in pancreatic cancer cells. 1864 Jan 31

Role of prostate apoptosis response-4 (PAR-4) has been well described in prostate cancer. However, its significance in other cancers has not been fully elucidated. For the current study, we selected four pancreatic cancer cell lines (BxPC-3, Colo-357, L3.6pl, and HPAC) that showed differential endogenous expression of PAR-4. We found that nonpeptidic small-molecule inhibitors (SMI) of Bcl-2 family proteins (apogossypolone and TW-37; 250 nmol/L and 1 micromol/L, respectively) could induce PAR-4-dependent inhibition of cell growth and induction of apoptosis. Sensitivity to apoptosis was directly related to the expression levels of PAR-4 (R = 0.92 and R2 = 0.95). Conversely, small interfering RNA against PAR-4 blocked apoptosis, confirming that PAR-4 is a key player in the apoptotic process. PAR-4 nuclear localization is considered a prerequisite for cells to undergo apoptosis, and we found that the treatment of Colo-357 and L3.6pl cells with 250 nmol/L SMI leads to nuclear localization of PAR-4 as confirmed by 4',6-diamidino-2-phenylindole staining. In combination studies with gemcitabine, pretreatment with SMI leads to sensitization of Colo-357 cells to the growth-inhibitory and apoptotic action of a therapeutic drug, gemcitabine. In an in vivo setting, the maximum tolerated dose of TW-37 in xenograft of severe combined immunodeficient mice (40 mg/kg for three i.v. injections) led to significant tumor inhibition. Our results suggest that the observed antitumor activity of SMIs is mediated through a novel pathway involving induction of PAR-4. To our knowledge, this is the first study reporting SMI-mediated apoptosis involving PAR-4 in pancreatic cancer.
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PMID:Critical role of prostate apoptosis response-4 in determining the sensitivity of pancreatic cancer cells to small-molecule inhibitor-induced apoptosis. 1879 Jul 69

Resistance to apoptosis is a hallmark of pancreatic cancer, a leading cause of cancer deaths. Therefore, novel strategies are required to target apoptosis resistance. Here, we report that the combination of X-linked inhibitor of apoptosis (XIAP) inhibition and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an effective approach to trigger apoptosis despite Bcl-2 overexpression and to suppress pancreatic cancer growth in vitro and in vivo. Knockdown of XIAP by RNA interference cooperates with TRAIL to induce caspase activation, loss of mitochondrial membrane potential, cytochrome c release, and apoptosis in pancreatic carcinoma cells. Loss of mitochondrial membrane potential and cytochrome c release are extensively inhibited by a broad range or caspase-3 selective caspase inhibitor and by RNAi-mediated silencing of caspase-3, indicating that XIAP inhibition enhances TRAIL-induced mitochondrial damage in a caspase-3-dependent manner. XIAP inhibition combined with TRAIL even breaks Bcl-2-imposed resistance by converting type II cells that depend on the mitochondrial contribution to the death receptor pathway to type I cells in which TRAIL-induced activation of caspase-3 and caspase-9 and apoptosis proceeds irrespective of high Bcl-2 levels. Most importantly, XIAP inhibition potentiates TRAIL-induced antitumor activity in two preclinical models of pancreatic cancer in vivo. In the chicken chorioallantoic membrane model, XIAP inhibition significantly enhances TRAIL-mediated apoptosis and suppression of tumor growth. In a tumor regression model in xenograft-bearing mice, XIAP inhibition acts in concert with TRAIL to cause even regression of established pancreatic carcinoma. Thus, this combination of XIAP inhibition plus TRAIL is a promising strategy to overcome apoptosis resistance of pancreatic cancer that warrants further investigation.
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PMID:Targeting XIAP bypasses Bcl-2-mediated resistance to TRAIL and cooperates with TRAIL to suppress pancreatic cancer growth in vitro and in vivo. 1882 53

Pancreatic cancer cells are resistant to the growth-inhibitory and apoptosis-inducing effects of conventional chemotherapeutic agents. There are multiple genetic and epigenetic events during the process of carcinogenesis that enable the cancer cells to avoid normal growth constraints and apoptosis. Investigation of the mechanisms involved has led to multiple strategies that encourage cell death and apoptosis to occur. The pathways involved are summarized in this review, together with some recently developed strategies to promote cell death in this cancer and with a particular focus on the frondoside A, a novel triterpenoid glycoside isolated from the Atlantic sea cucumber, Cucumaria frondosa. Frondoside A inhibited proliferation of AsPC-1 human pancreatic cancer cells in a concentration- and time-dependent manner, as measured by (3)H-thymidine incorporation and cell counting. In concert with inhibition of cell growth, frondoside A induced significant morphological changes consistent with apoptosis. Propidium iodide DNA staining showed an increase of sub-G0/G1 cell population of apoptotic cells induced by frondoside A. Frondoside A-induced apoptosis was confirmed by annexin V binding and TUNEL assay. Furthermore, western blotting showed a decrease in expression of Bcl-2 and Mcl-1, an increase in Bax expression, activation of caspases 3, 7, and 9, and an increase in the expression of the cyclin-dependent kinase inhibitor, p21. These findings show that frondoside A induced apoptosis in human pancreatic cancer cells through the mitochondrial pathway and activation of the caspase cascade. Finally, a very low concentration of frondoside A (10 mug/kg/day) inhibited growth of AsPC-1 xenografts in athymic mice. In conclusion, new chemotherapeutic agents are desperately needed for pancreatic cancer because of the poor responsiveness to currently available treatment options. Frondoside A has potent growth inhibitory effects on human pancreatic cancer cells, and the inhibition of proliferation is accompanied by marked apoptosis. Frondoside A may be valuable for the treatment or chemoprevention of this devastating disease.
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PMID:Review of the apoptosis pathways in pancreatic cancer and the anti-apoptotic effects of the novel sea cucumber compound, Frondoside A. 1883 99

Increased expression of glucose transporters has been reported in many cancers. It is not known whether Sodium dependent GLucose Transporter 1 (SGLT1) is up-regulated in pancreatic cancer. We studied the expression of SGLT1, Bcl-2 and p53 in primary pancreatic adenocarcinomas related to survival. In primary tumors, mean SGLT1-Hscore (n = 83) was 4.24 (median 3.0, range 0.5-15.0). Patients with positive staining for Bcl-2 had higher mean SGLT1-Hscores than those without Bcl-2 expression: 5.87 vs. 3.07 (P = 0.025). No correlation was found between expression of p53 and SGLT1 (P = 0.881). On multivariate analysis TNM stage (P = 0.015) and SGLT1 (P = 0.030) showed prognostic value for disease free survival (DFS). For overall survival (OS), TNM stage (P<0.001) and chemotherapy (P = 0.048) were prognostic and SGLT1 showed a trend (P = 0.071). In a subgroup of younger patients (age < or = median, 63.9 y) who did not receive chemotherapy, SGLT1 was a very strong predictor of DFS (P = 0.005). We conclude that high SGLT1 expression (H score > median, 3.0) in pancreatic adenocarcinomas was significantly correlated with DFS and a trend was found for OS, especially in younger patients. High SGLT1 expression in primary tumors was correlated with high Bcl-2 expression, not with p53 expression. This supports our hypothesis that SGLT1 and Bcl-2 expression could serve as prognostic markers in pancreatic cancer.
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PMID:Expression of SGLT1, Bcl-2 and p53 in primary pancreatic cancer related to survival. 1885 13

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