Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proteinase inhibitor 9 (PI-9, SerpinB9) is the only known human intracellular granzyme B inhibitor. Whether expression of PI-9 is sufficient to block cytolysis induced by cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells remains controversial. To evaluate the roles of PI-9, we isolated and tested three lines of stably transfected HeLa cells expressing wild-type PI-9 and one line expressing an inactive mutant PI-9. Expressions of wild-type PI-9, but not the inactive mutant PI-9, inhibited cytolysis induced by human NK92 and NKL natural killer cells. Expression of high levels of PI-9 is therefore sufficient to protect human cells against NK cell-mediated cell death. Using two assays, we show that expressing wild-type PI-9, but not the inactive mutant PI-9, blocks Fas/Fas ligand (Fas/FasL)-mediated apoptosis. PI-9 expression has no effect on etoposide-induced apoptosis. HeLa cells exhibiting substantial resistance to Fas/FasL-mediated apoptosis contain 2- to 3-fold higher PI-9 levels than HCT116 human colon cancer cells and 2- to 3-fold lower PI-9 levels than MCF7/ERHA breast cancer cells, in which PI-9 is strongly induced by estrogens, and by tamoxifen. Expression of increasing levels of PI-9 in target cells may progressively inhibit immune surveillance by blocking NK and CTL-induced cytotoxicity through the perforin/granzyme pathway and then through the Fas/FasL pathway.
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PMID:Expression of high levels of human proteinase inhibitor 9 blocks both perforin/granzyme and Fas/Fas ligand-mediated cytotoxicity. 1749 Jun 28

Human monocyte-derived dendritic cells (DCs), stimulated with granulocyte-macrophage colony-stimulating factor and interleukin-4 for 1 week, major histocompatibility complex killed human tumor cells in 24-hour cytotoxicity assays. These immature DCs were >90% CD11c, major histocompatibility complex class II(+), but <1% were CD83(+) cells. Within 24 hours, these DCs ingested tumor membranes. The DC cells also lysed Jurkat lymphoma cells, but not Jurkat cells genetically knocked out of the Fas-associated death domain (FADD) or caspase-8. DC2.4, a cloned murine DC line, also displayed cytotoxicity toward U-251 cells, although these murine DCs were less potent than human DC. DC2.4 did not kill Jurkat cells, rat T9 glioma cells, or human Caco-2 colon cancer cells, suggesting that a unique receptor or ligand interaction exists between the DC and U-251 cells. This interaction was destroyed by the paraformaldehyde fixation of the tumor cells. Supernatants from the cultures of DC2.4 and tumor cells were analyzed by the Griess reaction for signs of nitric oxide (NO) production. Augmented NO production occurred in DC2.4/U-251 and DC2.4/Jurkat cultures but was not seen in the human DC/U-251 cultures. These studies suggest that DCs possess different mechanisms of tumoricidal activity.
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PMID:Human allogeneic and murine xenogeneic dendritic cells are cytotoxic to human tumor cells via two distinct pathways. 1797 70

Tumor cells strategically down-regulate Fas receptor expression to evade immune attack and up-regulate expression of Fas ligand to promote apoptosis of infiltrating T lymphocytes. Many pathways leading to apoptotic cell death require calcium release from inositol 1,4,5-trisphosphate receptors (IP3Rs). Here, we show that Fas-dependent killing of Jurkat T lymphoma cells by SW620 colon cancer cells requires calcium release from IP3R. General suppression of IP3R signaling significantly reduced SW620-mediated Jurkat cell apoptosis. Significantly, a specific inhibitor of apoptotic calcium release from IP3R strongly blocked lymphocyte apoptosis. Thus, selective pharmacological targeting of apoptotic calcium release from IP3R may enhance tumor cell immunogenicity.
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PMID:Requirement of inositol 1,4,5-trisphosphate receptors for tumor-mediated lymphocyte apoptosis. 1836 56

Considerable researches have been done about integrin alphanubeta6 and carcinomas, but little information has been shown about the relationship between integrin alphanubeta6 and apoptosis. In this study, we investigated the apoptosis and its related signal pathways to integrin alphavbeta6 in colon cancer cells. After we blocked the function of integrin alphavbeta6 in HT29 cells used the monoclonal antibody, the apoptotic cells increased markedly. Meanwhile, cytochrome C released from mitochondria into cytosol, Bcl-2 decreased while Bax increased significantly, and Fas and Fas-ligand had no change. The activities of caspase-3 and caspase-9 increased, while caspase-8 remained no change. Moreover, the expression of phosphorylated extracellular signal-related kinase (P-ERK) decreased. We confirmed that integrin alphavbeta6 acted as an important role in inhibiting apoptosis in colon cancer cells, and the signaling involved the mitochondrial pathway.
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PMID:Signaling and regulatory mechanisms of integrin alphavbeta6 on the apoptosis of colon cancer cells. 1838 Dec 32

Tanshinone IIA is the most abundant diterpene quinone in Danshen, Salviae miltiorrhizae Radix, a widely prescribed traditional herbal medicine that is used to treat cardiovascular and inflammatory diseases. Recently, tanshinone IIA was demonstrated to induce cell death and apoptosis in a variety of tumors. However, the effect of tanshinone IIA on human colon cancer cells is not clearly understood yet. In this study, the antigrowth and apoptosis-eliciting effects of tanshinone IIA, as well as its cellular mechanisms of actions, were investigated in Colo-205 human colon cancer cells. Tanshinone IIA reduced cell growth in a concentration-dependent manner, inducing apoptosis accompanied by an increase in TUNEL staining and by an increased percentage of cells in the sub-G1 fraction. The expression of p53 and p21 and mitochondrial cytochrome c release were increased in tanshinone IIA-treated cells. In addition, the expression of Fas proteins was up-regulated by tanshinone IIA. Tanshinone IIA-induced catalytic activation of caspases was confirmed by cleavage of caspase-8 and caspase-3. These findings suggest that tanshinone IIA induces apoptosis in Colo-205 cells through both mitochondrial-mediated intrinsic and Fas-mediated extrinsic caspase cell-death pathways. Accordingly, the chemotherapeutic potential of tanshinone IIA for colon cancer warrants further study.
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PMID:Growth inhibition and apoptosis induction by tanshinone IIA in human colon adenocarcinoma cells. 1862 3

Fas ligand (FasL/CD95L) is a member of the tumour necrosis factor superfamily that triggers apoptosis following crosslinking of the Fas receptor. Despite studies strongly implicating tumour-expressed FasL as a major inhibitor of the anti-tumour immune response, little is known about the mechanisms that regulate FasL expression in tumours. In this study, we show that the cyclooxygenase (COX) signalling pathway, and in particular prostaglandin E(2) (PGE(2)), plays a role in the upregulation of FasL expression in colon cancer. Suppression of either COX-2 or COX-1 by RNA interference in HCA-7 and HT29 colon tumour cells reduced FasL expression at both the mRNA and protein level. Conversely, stimulation with PGE(2) increased FasL expression and these cells showed increased cytotoxicity against Fas-sensitive Jurkat T cells. Prostaglandin E(2)-induced FasL expression was mediated by signalling via the EP1 receptor. Moreover, immunohistochemical analysis using serial sections of human colon adenocarcinomas revealed a strong positive correlation between COX-2 and FasL (r=0.722; P<0.0001) expression, and between EP1 receptor and FasL (r=0.740; P<0.0001) expression, in the tumour cells. Thus, these findings indicate that PGE(2) positively regulates FasL expression in colon tumour cells, adding another pro-neoplastic activity to PGE(2).
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PMID:Prostaglandin E2 stimulates Fas ligand expression via the EP1 receptor in colon cancer cells. 1864 68

In this study, we investigated the effects of DADS on human colon cancer cell line COLO 205 on cell cycle arrest and apoptosis in vitro. After 24 h treatment of COLO 205 cells with DADS, the dose- and time-dependent decreases of viable cells were observed and the IC50 was 22.47 microM. The decreased percentages of viable cells are associated with the production of ROS. Treatment of COLO 205 cells with DADS resulted in G2/M phase arrest and apoptosis occurrence through the mitochondrial-pathway (Bcl-2, Bcl-xL down-regulation and Bak, Bax up-regulation). DADS increased cyclin B, cdc25c-ser-216-9 and Wee1 but did not affect CDK1 protein and gene expression within 24 h of treatment. DADS-induced apoptosis was examined and confirmed by DAPI staining and DNA fragmentation assay. DADS promoted caspase-3, -8 and -9 activity and induced apoptosis were accompanied by increasing the levels of Fas, phospho-Ask1 and -JNK, p53 and decreasing the mitochondrial membrane potential which then led to release the cytochrome c, cleavage of pro-caspase-9 and -3. The COLO 205 cells were pre-treated with JNK inhibitor before leading to decrease the percentage of apoptosis which was induced by DADS. Inhibition of caspase-3 activation blocked DADS-induced apoptosis on COLO 205 cells.
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PMID:Diallyl disulfide induces apoptosis in human colon cancer cell line (COLO 205) through the induction of reactive oxygen species, endoplasmic reticulum stress, caspases casade and mitochondrial-dependent pathways. 1903 4

The plant sterol guggulsterone has recently been shown to have anti-tumorigenic potential. This study was designed to investigate the anti-tumor efficacy of guggulsterone and to elucidate its molecular mechanisms in colon cancer. Guggulsterone significantly increased apoptosis in HT-29 cells by activating caspases-3 and -8. Furthermore, guggulsterone decreased cIAP-1, cIAP-2, and Bcl-2 levels and increased the levels of truncated Bid, Fas, p-JNK, and p-c-Jun. The size of HT-29 xenograft tumors in guggulsterone-treated mice was significantly smaller than of the size of tumors in control mice. The present study suggests a potential therapeutic use for this compound in the treatment of colorectal cancer.
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PMID:Guggulsterone induces apoptosis in colon cancer cells and inhibits tumor growth in murine colorectal cancer xenografts. 1923 20

The human inducible nitric oxide synthase (hiNOS) gene is regulated by nuclear factor kappaB (NF-kappaB) and has recently been shown to be a target of the Wnt/beta-catenin pathway. In this study, we tested the hypothesis that Wnt/beta-catenin signaling might regulate cytokine- or tumor necrosis factor alpha (TNFalpha)-induced hiNOS expression through interaction with NF-kappaB. A cytokine mixture of TNFalpha + interleukin (IL)-1beta + IFNgamma induced a 2- to 3-fold increase in hiNOS promoter activity in HCT116 and DLD1 colon cells, but produced a 2-fold decrease in SW480 colon cancer cells. A similar differential activity was seen in liver cancer cells (HepG2, Huh7, and Hep3B). Overexpression of beta-catenin produced a dose-dependent decrease in NF-kappaB reporter activity and decreased cytokine mixture-induced hiNOS promoter activity. Gel shift for TNFalpha-induced hiNOS NF-kappaB activation showed decreased p50 binding and decreased NF-kappaB reporter activity in the beta-catenin-mutant HAbeta18 cells. Conversely, enhanced p50 binding and increased NF-kappaB reporter activity were seen in HAbeta85 cells, which lack beta-catenin signaling. Coimmunoprecipitation confirmed that beta-catenin complexed with both p65 and p50 NF-kappaB proteins. NF-kappaB-dependent Traf1 protein expression also inversely correlated with the level of beta-catenin. Furthermore, SW480 cells stably transformed with wild-type adenomatous polyposis coli showed decreased beta-catenin protein and increased TNFalpha-induced p65 NF-kappaB binding as well as iNOS and Traf1 expression. Finally, beta-catenin inversely correlated with iNOS and Fas expression in vivo in hepatocellular carcinoma tumor samples. Our in vitro and in vivo data show that beta-catenin signaling inversely correlates with cytokine-induced hiNOS and other NF-kappaB-dependent gene expression. These findings underscore the complex role of Wnt/beta-catenin, NF-kappaB, and iNOS signaling in the pathophysiology of inflammation-associated carcinogenesis.
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PMID:Wnt/beta-catenin signaling regulates cytokine-induced human inducible nitric oxide synthase expression by inhibiting nuclear factor-kappaB activation in cancer cells. 1938

Treatment of Jurkat T cells with Fas-activating antibody (CH-11) facilitated rapid cell death that was shown to be caspase-dependent apoptosis. The expression of miR-143 was up-regulated during the apoptosis with time. The increased expression of miR-143 emerged from 1 to 2h after the treatment, at which time the caspases-8 and -3 were also activated; and this increase was almost canceled by the pretreatment with an inhibitor of caspase-3 or -8. Furthermore, the transfection of Jurkat cells with mature miR-143 induced a significant growth suppression and enhancement of CH-11-induced apoptosis. On the contrary, an extracellular signal-regulated protein kinase 5 (ERK5), which was determined to be a target of miR-143 in colon cancer DLD-1 cells, was time-dependently down-regulated at the translational level after the treatment. During the apoptosis, the expression level of FasL was maintained and the level of nuclear-Foxo3a was increased in the early phase. These data suggest that the up-regulation of miR-143 could be related to the apoptosis in part by targeting ERK5, which leads to promotion of Foxo3a/FasL positive feedback loop.
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PMID:Role of microRNA-143 in Fas-mediated apoptosis in human T-cell leukemia Jurkat cells. 1946 56


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