Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Smac, a second mitochondria-derived activator of caspases, promotes caspase activation in the cytochrome c (cyto-c)/Apaf-1/caspase-9 pathway. Here, we show that treatment of multiple myeloma (MM) cells with dexamethasone (Dex) triggers the release of Smac from mitochondria to cytosol and activates caspase-9 without concurrent release of cyto-c and Apaf-1 oligomerization. Smac binds to XIAP (an inhibitor of apoptosis protein) and thereby, at least in part, eliminates its inhibitory effect on caspase-9. Interleukin-6, a growth factor for MM, blocks Dex-induced apoptosis and prevents release of Smac. Taken together, these findings demonstrate that Smac plays a functional role in mediating Dex-induced caspase-9 activation and apoptosis in MM cells.
 ...
PMID:Apaf-1/cytochrome c-independent and Smac-dependent induction of apoptosis in multiple myeloma (MM) cells. 1135 22

Interleukin-6 (IL-6) and insulin-like growth factor-1 (IGF-1) promote the proliferation of multiple myeloma (MM) cells and protect them against dexamethasone (Dex)-induced apoptosis. We have previously shown that Apo2 ligand/TNF-Related apoptosis inducing ligand (Apo2L/TRAIL) induces apoptosis of MM cells, including cells either sensitive or resistant to Dex and cytotoxic drugs, and overcomes the growth and survival effect of IL-6; conversely, NF-kappaB transcriptional activity attenuates their Apo2L/TRAIL-sensitivity. In the current study, we demonstrate that IGF-1 stimulates sustained activation of NF-kappaB and Akt; induces phosphorylation of the FKHRL-1 Forkhead transcription factor; upregulates a series of intracellular anti-apoptotic proteins including FLIP, survivin, cIAP-2, A1/Bfl-1, and XIAP; and decreases Apo2L/TRAIL-sensitivity of MM cells. In contrast, IL-6 does not cause sustained NF-kappaB activation, induces less pronounced Akt activation and FKHRL-1 phosphorylation than IGF-1, and increases the expression of only survivin. Forced overexpression of constitutively active Akt in MM-1S cells reduced their sensitivity to Apo2L/TRAIL and to doxorubicin (Doxo). In contrast, the Akt inhibitor IL-6-Hydroxymethyl-chiro-inositol 2-(R)-2-O-methyl-3-O-octadecylcarbonate induced cell death of both Dex- and Doxo-sensitive and -resistant cells; opposed the protective effect of constitutive Akt activity against Apo2L/TRAIL; and abrogated the NF-kappaB activation, increase of anti-apoptotic proteins and protection against Apo2L/TRAIL induced by IGF-1. These findings therefore define an important role of the Akt pathway in modulating tumor cell responsiveness to Apo2L/TRAIL, delineate molecular mechanisms for the survival effects of IGF-1, and characterize differential pathophysiologic sequelae of IGF-1 vs IL-6 on MM cells. Importantly, they provide the basis for future clinical trials in MM combining conventional or novel agents with strategies designed to neutralize IGF-1.
 ...
PMID:Activation of NF-kappaB and upregulation of intracellular anti-apoptotic proteins via the IGF-1/Akt signaling in human multiple myeloma cells: therapeutic implications. 1217 37

Interactions between pharmacologic NF-kappaB inhibitors (eg, Bay 11-7082, SN-50) and the checkpoint abrogator UCN-01 have been examined in human multiple myeloma (MM) cells. Exposure of U266 cells to Bay 11-7082 (Bay) in combination with UCN-01 resulted in the abrogation of NF-kappaB/DNA binding activity and the synergistic induction of apoptosis. Comparable synergism was observed in other MM cell lines and patient-derived CD138+ cells and between an inhibitory peptide of NF-kappaB (SN50) and UCN-01. Bay/UCN-01-mediated lethality involved mitochondrial dysfunction, caspase cleavage, and poly adenosine diphosphate-ribose polymerase (PARP) degradation. Although Bay modestly blocked UCN-01-induced extracellular signal-regulated kinase (ERK) phosphorylation, coadministration activated c-Jun N-terminal kinase (JNK) and cdc2/cdk1 and down-regulated Mcl-1, XIAP, and Bcl-xL. Transfection with a constitutively activated mitogen-activated protein kinase kinase (MEK1)/green fluorescent protein (GFP) construct failed to block apoptosis induced by Bay/UCN-01 but significantly attenuated MEK inhibitor (U0126)/UCN-01-induced lethality. Inhibiting JNK activation with SP600125 or D-JNKI1 peptide markedly reduced Bay/UCN-01-mediated mitochondrial dysfunction and apoptosis and the down-regulation of Mcl-1, XIAP, and Bcl-xL but not of cdc2/cdk1 activation. Stable transfection of cells with dominant-negative caspase-9 dramatically diminished Bay/UCN-01 lethality without altering JNK or cdc2/cdk1 activation. Neither interleukin-6 (IL-6)- nor fibronectin-mediated adherence conferred resistance to Bay/UCN-01-induced apoptosis. Together, these findings suggest that a strategy combining UCN-01 with disruption of the IkappaB kinase (IKK)/IkappaB/NF-kappaB pathway warrants attention in MM.
 ...
PMID:Interruption of the NF-kappaB pathway by Bay 11-7082 promotes UCN-01-mediated mitochondrial dysfunction and apoptosis in human multiple myeloma cells. 1464 3

Resveratrol has been proposed to act as a chemopreventive agent in numerous epidemiologic studies and has been shown to inhibit proliferation of various tumor cells in vitro. In the present study, we investigated the antitumor effects of resveratrol on multiple myeloma (MM) cells and the mechanisms involved. Our findings indicated that resveratrol inhibited proliferation of tumor cells in a dose- [corrected] dependent manner by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and [3H]thymidine incorporation assay. Resveratrol also enhanced the inhibitory effect of dexamethasone on the growth of MM cells by MTT assay. Flow cytometric analysis demonstrated that resveratrol arrested the cells at the G1 and S phases of the cell cycle. Because nuclear factor-kappaB (NF-kappaB) plays a key role in cell survival and proliferation of human MM cells, we tested the effect of resveratrol on NF-kappaB expression by Western blot analysis and immunofluorescence. NF-kappaB was constitutively active in all human MM cell lines examined, and resveratrol down-regulated NF-kappaB expression in all cell lines. Resveratrol also down-regulated the expression of NF-kappaB-regulated gene products by Western blot analysis, gelatin zymography, and enzyme-linked immunosorbent assay, including interleukin-6, Bcl-2, Bcl-xL, XIAP, c-IAP, vascular endothelial growth factor (VEGF), and matrix metalloproteinase-9 (MMP-9), which modulates an array of signals controlling cellular survival and proliferation and tumor promotion. Indeed, annexin V-fluoroisothyocyanate and Transwell invasion analyses revealed that incubation of MM cells with resveratrol resulted in apoptotic cell death and inhibition of invasion. In conclusion, these data suggest that resveratrol is an effective in vitro inhibitor of NF-kappaB in human MM cells. Resveratrol plays a role in suppressing the proliferation of MM cells and induces apoptosis, thus providing the molecular basis for the treatment of MM patients with this compound.
 ...
PMID:Resveratrol downregulates the constitutional activation of nuclear factor-kappaB in multiple myeloma cells, leading to suppression of proliferation and invasion, arrest of cell cycle, and induction of apoptosis. 1649 May 92

Fludarabine, a nucleoside analogue, plays a major role in the treatment of B-cell lymphocytic leukemia, hairy cell leukemia, and indolent lymphomas. There is a controversy about antitumor activity of fludarabine in multiple myeloma (MM). The aim of this study was to evaluate the activity of fludarabine against human myeloma cells both in vivo and in vitro. We demonstrated that myeloma cell line RPMI8226 was efficiently inhibited by fludarabine, concomitantly with decreased phosphorylation of Akt, down-regulation of the inhibitor of apoptosis proteins (IAP) family, including XIAP and survivin, and induction of apoptosis related to activation of caspase cascade. Contrary to dexamethasone, the effect of fludarabine on RPMI8226 cells was independent of interleukin-6. Fludarabine also induced cytotoxicity in dexamethasone-sensitive (MM.1S) and -resistant (MM.1R) cells at 48 h with IC50 of 13.48 microg/mL and 33.79 microg/mL, respectively. In contrast, U266 cells were resistant to fludarabine. Moreover, RPMI8226 myeloma xenograft model was established using severe combined immunodeficient mice. The tumors treated with fludarabine at 40 mg/kg increased less than 5-fold in 25 d comparing with approximately 10-fold in the control tumors, demonstrating the antitumor activity of fludarabine in vivo. These results suggest that fludarabine may be an important therapeutic option for MM patients who are resistant to dexamethasone.
 ...
PMID:Antitumor activity of fludarabine against human multiple myeloma in vitro and in vivo. 1797 86

Recent studies have shown that naturally occurring compounds can enhance the efficacy of chemotherapeutic drugs. The objectives of this study were to investigate the molecular mechanisms by which diallyl trisulfide (DATS) enhanced the therapeutic potential of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in prostate cancer cells in vitro and on orthotopically transplanted PC-3 prostate carcinoma in nude mice. DATS inhibited cell viability and colony formation and induced apoptosis in PC-3 and LNCaP cells. DATS enhanced the apoptosis-inducing potential of TRAIL in PC-3 cells and sensitized TRAIL-resistant LNCaP cells. Dominant-negative FADD inhibited the synergistic interaction between DATS and TRAIL on apoptosis. DATS induced the expression of DR4, DR5, Bax, Bak, Bim, Noxa, and PUMA and inhibited expression of Mcl-1, Bcl-2, Bcl-X(L), survivin, XIAP, cIAP1, and cIAP2. Oral administration of DATS significantly inhibited growth of orthotopically implanted prostate carcinoma in BALB/c nude mice compared with the control group, without causing weight loss. Cotreatment of mice with DATS and TRAIL was more effective in inhibiting prostate tumor growth and inducing DR4 and DR5 expression, caspase-8 activity, and apoptosis than either agent alone. DATS inhibited angiogenesis (as measured by CD31-positive and factor VIII-positive blood vessels and hypoxia-inducible factor-1alpha, vascular endothelial growth factor, and interleukin-6 expression) and metastasis [matrix metalloproteinase (MMP)-2, MMP-7, MMP-9, and MT-1 MMP expression], which were correlated with inhibition in AKT and nuclear factor-kappaB activation. The combination of DATS and TRAIL was more effective in inhibiting markers of angiogenesis and metastasis than either agent alone. These data suggest that DATS can be combined with TRAIL for the prevention and/or treatment of prostate cancer.
 ...
PMID:Diallyl trisulfide increases the effectiveness of TRAIL and inhibits prostate cancer growth in an orthotopic model: molecular mechanisms. 1872 80

Involvement of phosphatidylinositol 3-kinase/Akt-1 in cell survival and proliferation of multiple myeloma (MM) has been well established. In this study, we demonstrate that homoharringtonine (HHT), an antileukemic drug first isolated from the Chinese evergreen Cephalotaxus harringtonia, induces significant cytotoxicity in dexamethasone-sensitive and -resistant and chemotherapy-sensitive MM cell lines in a time and dose-dependent manner. HHT also triggers apoptosis in chemotherapy-resistant patient's myeloma cells. Contrary to dexamethasone, the cytotoxicity of HHT on myeloma is independent of interleukin-6. The mechanism of HHT cytotoxicity is related to down-regulation of Akt phosphorylation/activation and various target genes of Akt including nuclear factor kappa B, XIAP, cIAP and cyclin D1. Moreover, in vivo antitumor activity of HHT is demonstrated in RPMI8226 myeloma xenograft model. Importantly, an additive effect of antitumor is confirmed in the myeloma cells treated with HHT and bortezomib concomitantly with inhibition of phosphorylated Akt. Together, these findings obtained with HHT should give useful insights into a novel antimyeloma chemotherapy.
 ...
PMID:Homoharringtonine inhibits the AKT pathway and induces in vitro and in vivo cytotoxicity in human multiple myeloma cells. 1894 18

Aspirin has been reported to induce apoptosis in various cancer cell lines. However, the apoptotic effects of aspirin on human brain tumor cells are not well understood. Here, we have assessed the effect of aspirin on human gliobalstoma cell line A172 and found that aspirin induced the apoptosis of A172 cells, as determined by TUNEL assay, FACS analysis, and Hoechst staining. The underlying mechanism of this effect consists of reduction in the level of phosphorylated STAT3 (Tyr705), a transcription factor required for survival of A172 cells. Moreover, the expression of STAT3 target genes such as Cyclin D1, XIAP, and Bcl-2 that are essential for cell growth and survival was apparently attenuated after aspirin treatment. We also showed that the expression and secretion of interleukin-6 (IL-6), leading to STAT3 phosphorylation, was inhibited by aspirin. When administered exogenous IL-6 to aspirin-treated A172 cells, the phosphorylation of STAT3 and cellular apoptosis were restrained compared to aspirin only-treated cells. Taken together, our results indicate that aspirin causes apoptosis via down-regulation of IL-6-dependent STAT3 signaling, suggesting that aspirin could be therapeutically useful for a potential anti-glioblastoma therapeutic approach.
 ...
PMID:Aspirin induces apoptosis through the blockade of IL-6-STAT3 signaling pathway in human glioblastoma A172 cells. 1959 69

Interleukin-6 (IL-6) is an important growth factor for myeloma cells. IL-6 promotes the survival and proliferation of multiple myeloma (MM) cells through the phosphorylated proteins, including STAT3, MAPK, and Akt. Chemical components that suppress the signaling proteins' phosphorylation have a potential role for MM therapy. We recently identified that baicalein, a component of Scutellaria radix, suppressed proliferation and induced apoptosis of myeloma cells by blocking IkappaB-alpha degradation followed by down-regulating IL-6 and XIAP gene expression. In the present study of four myeloma cell lines, namely U266, NOP2, AMO1, and ILKM2, we demonstrated that baicalein not only inhibited IL-6-mediated phosphorylation of signaling proteins, such as Jak, STAT3, MAPK, and Akt, but also inhibited the expression of their target genes, such as bcl-xl. Finally, baicalein facilitated myeloma cell proliferation inhibited by dexamethasone. In contrast, baicalin, another major flavonoid derived from Scutellaria radix, had no significant effect on IL-6-mediated protein phosphorylation. Baicalein had no effect on Akt phosphorylation induced by the insulin-like growth factor-1 (IGF-1) in NOP2 cells. Compared with PD98059, an MAPK inhibitor, baicalein exhibited a stronger inhibitory effect on Erk(1/2) phosphorylation. Our results demonstrate that baicalein is a potent inhibitor of protein phosphorylation induced by IL-6, and thus may be a useful agent for the treatment of MM.
 ...
PMID:Inhibitory effect of baicalein on IL-6-mediated signaling cascades in human myeloma cells. 1987 71

NVP-BKM120 is a novel phosphatidylinositol 3-kinase (PI3K) inhibitor and is currently being investigated in phase I clinical trials in solid tumors. This study aimed to evaluate the therapeutic efficacy of BKM120 in multiple myeloma (MM). BKM120 induces cell growth inhibition and apoptosis in both MM cell lines and freshly isolated primary MM cells. However, BKM120 only shows limited cytotoxicity toward normal lymphocytes. The presence of MM bone marrow stromal cells, insulin-like growth factor, or interleukin-6 does not affect BKM120-induced tumor cell apoptosis. More importantly, BKM120 treatment significantly inhibits tumor growth in vivo and prolongs the survival of myeloma-bearing mice. In addition, BKM120 shows synergistic cytotoxicity with dexamethasone in dexamethasone-sensitive MM cells. Low doses of BKM120 and dexamethasone, each of which alone has limited cytotoxicity, induce significant cell apoptosis in MM.1S and ARP-1. Mechanistic study shows that BKM120 exposure causes cell cycle arrest by upregulating p27 (Kip1) and downregulating cyclin D1 and induces caspase-dependent apoptosis by downregulating antiapoptotic XIAP and upregulating expression of cytotoxic small isoform of Bim, BimS. In summary, our findings demonstrate the in vitro and in vivo anti-MM activity of BKM120 and suggest that BKM120 alone or together with other MM chemotherapeutics, particularly dexamethasone, may be a promising treatment for MM.
 ...
PMID:Novel phosphatidylinositol 3-kinase inhibitor NVP-BKM120 induces apoptosis in myeloma cells and shows synergistic anti-myeloma activity with dexamethasone. 2220 85


1 2 Next >>